We are asked about the first choice treatment for glaucoma. In the past, beta-blockers were the first choice, but nowadays they have been displaced by the group that lowers intraocular pressure the most: prostaglandins. Their efficacy and more convenient dosage (once a day) generally make them the group of choice. Beta-blockers would remain as a second choice in cases in which the side effects of prostaglandins (change in eye color, increase in eyelash size) make us initially leave them aside. Since the patient is asthmatic, we should rule out beta-blockers (wrong answer 2). Also, since we need a significant drop in intraocular pressure because the numbers are high (34 and 31), we can also rule out carbonic anhydrase inhibitors and alpha-2 agonists (options 1 and 3 incorrect). And opt for the group that can lower intraocular pressure the most. Answer 4 correct. And then a couple of nuances of the statement. It would be more correct to talk about intraocular pressure and not "ocular pressure". And the wording could be improved so as not to repeat the word "as" in the last sentence.

We are asked about the first choice treatment for glaucoma. In the past, beta-blockers were the first choice, but nowadays they have been displaced by the group that lowers intraocular pressure the most: prostaglandins. Their efficacy and more convenient dosage (once a day) generally make them the group of choice. Beta-blockers would remain as a second choice in cases in which the side effects of prostaglandins (change in eye color, increase in eyelash size) make us initially leave them aside. Since the patient is asthmatic, we should rule out beta-blockers ([HIDDEN]). Also, since we need a significant drop in intraocular pressure because the numbers are high (34 and 31), we can also rule out carbonic anhydrase inhibitors and alpha-2 agonists ([HIDDEN]). And opt for the group that can lower intraocular pressure the most. [HIDDEN]. And then a couple of nuances of the statement. It would be more correct to talk about intraocular pressure and not "ocular pressure". And the wording could be improved so as not to repeat the word "as" in the last sentence.

A 67-year-old man, diabetic and asthmatic, with primary open-angle glaucoma in both eyes. He has an ocular pressure of 34 mmHg in his right eye and 31 mmHg in his left eye. Which of the following pharmacological groups is the most indicated as first choice as hypotensive treatment?

[Evaluation of the effect of prostaglandin analogues and a carbonic anhydrase inhibitor/β-blocker combination on the ocular blood flow in patients with primary open-angle glaucoma].

To assess the effect of latanoprost and fixed combination of dorzolamide/timolol on ocular hemodynamics in patients with primary open-angle glaucoma (POAG). The study examined 34 patients (56 eyes) aged 51 to 69 years (average - 62.4±9.7 years) diagnosed with POAG in the initial (31 eyes) or advanced stage (25 eyes). Patients of the first group (20 patients, 36 eyes) were receiving latanoprost (Glauprost, Rompharm Company, Romania). The second group (14 patients, 20 eyes) was assigned to receive a fixed combination of dorzolamide/timolol (Dorzopt plus, Rompharm Company, Romania). Patient examination before and at 6 and 12 months included tonometry (ICare PRO), perimetry (Heidelberg Edge Perimeter), HRT and OCT of the optic nerve (Heidelberg Retina Tomograph 3 and Spectralis OCT2), as well as measurement of the density of surface (SVL) and deep (DVL) vascular plexus, and the Bruch's membrane opening minimum rim width (BMO-MRW). Additionally, we evaluated microcirculation in the choroid (MC) according to our original technique that uses Spectralis OCT2, and calculated rheographic index (RI) and stroke volume using transpalpebral rheoophthalmography. The decrease in IOP in the Latanoprost group was on average 27% and in the control group receiving timolol and dorzolamide - on average 22% and remained stable until the end of the study. The value of the area and volume of the disc rim band, BMO-MRW did not exhibit statistically significant changes in both groups by the 12th month of observation. A tendency to increase the RI from 51.5±24.5 to 62.2±19 (p=0.084) and the median of the index of microcirculation of the choroid (MC) from 16476 up to 23767 (p=0.062) in 1st group was observed. The study confirms the feasibility of using latanoprost and a fixed combination of dorzolamide and timolol in ocular hypotensive therapy of glaucoma thanks to their pronounced hypotensive effect. Patients were noted to have a tendency for improvement of ocular hemodynamics when using latanoprost.

Pharmacological management of primary open-angle glaucoma: second-line options and beyond.

Glaucoma is one of the leading causes of blindness worldwide. Increased intraocular pressure (IOP) is considered to be the most important risk factor. Major outcome studies from recent years have shown that lowering IOP is beneficial in primary open-angle glaucoma and ocular hypertension. The introduction of new classes of IOP-lowering drugs (alpha(2)-adrenoceptor agonists, topical carbonic anhydrase inhibitors and hypotensive lipids) in the last decade has contributed to a change in the drug prescription pattern. Together with beta-adrenoceptor antagonists (beta-blockers), these drugs are now considered to be first-choice classes, giving ophthalmologists ample opportunities to choose from a broad spectrum of IOP-lowering drugs. The number of possible medical treatment combinations has increased likewise.We review medical treatment combinations of two, three or four drugs from the four major first-choice glaucoma drug classes and provide an overview of the scientific evidence for IOP efficacy of second-line medical options when first-line therapy has been effective but additional IOP lowering is necessary. A systematic search of the literature initially revealed 2729 publications. After a thorough selection process, 42 studies were found to be eligible for inclusion in the review. Publications were excluded if the primary endpoint of the study was not IOP or if glaucoma topics other than IOP lowering of drugs were studied. In addition, studies that reported results for monotherapies only were excluded. The vast majority of study arms reported on combinations of a beta-blocker with either a carbonic anhydrase inhibitor or a hypotensive lipid. For a number of treatment combinations no eligible studies were available or could be included.This review shows that combining drugs from the different first-choice classes results in an additional IOP decrease. The exact magnitude of this additional decrease and the patients to whom it applies remain unclear. In many studies, no information on IOP before the run-in phase was available. However, such data are important in order to determine whether patients with high untreated IOP or patients non-responsive to the run-in drug(s) were preferentially included. Another issue that hampers interpretation is the fact that the timepoints of measurements of IOP before and after adding a drug should be related to the peak and trough times of the drugs. Finally, differences between concomitant use and fixed combined use of drugs may have consequences for the interpretation of results.

Glaucoma medication

An initial reduction in the intraocular pressure of 20% from baseline is suggested. However, reduction of IOP to the target pressure range does not guarantee that progression will not occur. Therefore, the target pressure range needs to be constantly reassessed and changed as dictated by IOP fluctuations, optic nerve changes, and/or visual field progression. Medical uses Medications are divided into several groups based on chemical structure and pharmacologic action. Agents in common clinical use include: Prostaglandin analogs Parasympathomimetic (miotic) agents, including cholinergic and anticholinesterase agents Carbonic anhydrase inhibitors (oral and topical) Adrenergic antagonists (nonselective and selective Beta1-antagonists) Alpha 2 agonists Hyperosmotic agents When comparing people with primary open-angle glaucoma and ocular hypertension, medical intraocular pressure lowering treatment slowed down the progression of visual field loss. Comparison table

Glaucoma and its treatment: a review.

A review of glaucoma and its treatment is presented. Glaucoma is a common eye disease that can cause irreversible blindness if left undiagnosed and untreated. Glaucoma is a leading cause of blindness in the United States and other industrialized countries. In most cases, the symptoms of early-stage glaucoma are minimal or nonexistent. There are several different types of glaucoma, and they have been classically divided into the categories of primary or secondary open-angle or angle-closure glaucoma. Secondary forms of glaucoma are caused by various ocular or systemic diseases. Every available treatment to prevent progressive glaucomatous optic neuropathy has potential adverse effects and involves a certain amount of risk and financial expense. Conventional first-line treatment of glaucoma usually begins with the use of a topical selective or nonselective beta-blocker or a topical prostaglandin analog. Second-line drugs of choice include alpha-agonists and topical carbonic anhydrase inhibitors. Parasympathomimetic agents, most commonly pilocarpine, are considered third-line treatment options. For patients who do not respond to antiglaucoma medications, laser trabeculoplasty and incisional surgery are further methods that can be used to lower intraocular pressure. The results of clinical trials have reaffirmed the utility of antiglaucoma medications in slowing the progression of the disease. Glaucoma is a common eye disease that is usually associated with an elevated intraocular pressure. Treatment options for patients with glaucoma include medications, laser therapy, and incisional surgery. The risks and benefits of each type of treatment must be carefully considered to maximize the treatment's benefits while minimizing adverse effects.

The one-eye trial and fellow eye response to prostaglandin analogues.

To determine if the intraocular pressure (IOP) reduction in one-eye trial correlates with the IOP reduction in the fellow eye when IOP variability during office hours is taken into account. This retrospective observational case series includes 50 high tension (primary open-angle glaucoma, exfoliative glaucoma and ocular hypertension; Group 1) and 21 normal tension (Group 2) glaucoma patients. Charts of bilateral open-angle glaucoma patients at Glaucoma Unit, School of Medicine, Adnan Menderes University who had pretreatment baseline office IOP measurements at 9:30, 11:30 and 15:30; were put on a one-eye trial with prostaglandin analogues, and then subsequently received the same medication in the fellow eye were reviewed. Pretreatment baseline office IOP measurements and reductions in the first and second eyes were compared to determine variability and correlation, respectively. Both groups showed significant variability in pretreatment baseline office IOP measurements. Peak IOP level was before noon in at least 70% of eyes in Group 1, 50% in Group 2. IOP dropped a mean of 8.8 +/- 4.8 mmHg (34%, P = < 0.0001) in Group 1 and 4.9 +/- 2.4 mmHg (30%, P = < 0.0001) in Group 2 during the one-eye trial. Following bilateral use of the medication a mean drop of 7.5 +/- 4.0 mmHg (31%, P = < 0.0001) in Group 1 and 2.9 +/- 1.9 mmHg (18%, P = < 0.0001) in Group 2 were obtained. The IOP reduction between fellow-eye pairs were significantly correlated in Group 1 (r = 0.541, P = < 0.0001) but not Group 2 (r =-0.310, P = 0.171). One-eye trial is a feasible method to determine the effectiveness of prostaglandin analogues and to predict the amount of IOP reduction in the fellow eye in patients with high tension glaucoma.

Eye drop

Glaucoma Eye drops used in managing glaucoma help the eye's fluid to drain better and decrease the amount of fluid made by the eye which decreases eye pressure. They are classified by their active ingredient and they include: prostaglandin analogs, beta blockers, alpha agonists, and carbonic anhydrase inhibitors. There are also combination drugs available for those patients who require more than one type of medication. Mydriatic eye drops These make the eye's pupil widen to maximum, to let an optometrist have the best view inside the eyeball behind the iris. Afterwards in sunny weather they can cause dazzling and photophobia until the effect of the mydriatic has worn off.

Glaucoma

Diagnosis is made by looking for cupping of the optic nerve. Prostaglandin agonists work by opening uveoscleral passageways. Beta-blockers, such as timolol, work by decreasing aqueous formation. Carbonic anhydrase inhibitors decrease bicarbonate formation from ciliary processes in the eye, thus decreasing the formation of aqueous humor. Parasympathetic analogs are drugs that work on the trabecular outflow by opening up the passageway and constricting the pupil. Alpha 2 agonists (brimonidine, apraclonidine) both decrease fluid production (via inhibition of AC) and increase drainage. Developmental glaucoma Developmental glaucoma (Q15.0) Primary congenital glaucoma Infantile glaucoma Glaucoma associated with hereditary or familial diseases

Prostaglandin analogues in the treatment of glaucoma.

Prostaglandin (PG) analogues are a new class of ocular hypotensive drugs that have been developed for the treatment of open angle glaucoma. Two of these drugs, latanoprost and unoprostone, are presently commercially available. Latanoprost was introduced in 1996 in the US and Europe. Presently it enjoys the most widespread use and is the most well documented drug of this group. It reduces the intraocular pressure (IOP) by a mechanism of action different from other drugs; namely by increasing the uveoscleral outflow. The aqueous inflow is not affected. The optimal dose regimen is one drop of 50 microg/ml once daily, which reduces the IOP by approximately 30% in patients with glaucoma. A more pronounced ocular hypotensive effect is demonstrated when latanoprost is combined with other glaucoma therapies, including beta-blockers, adrenergic and cholinergic agonists or carbonic anhydrase inhibitors. Latanoprost is well tolerated. The drug reaches a plasma concentration below that needed for stimulation of the FP-receptor, which may explain its favourable systemic tolerability profile. The major ocular adverse effect is increased iris pigmentation, which is due to increased synthesis of melanin in the melanocytes of the iris stroma. It is most frequently seen in green-brown eyes and it is probably permanent. A low frequency of cystoid macular oedema has also been reported, predominantly in predisposed eyes. Unoprostone was launched in Japan in 1994, but there is little experience with this drug outside the Japanese market and the documentation is more limited. Its main mechanism of action is on outflow, but this is not yet fully elucidated. The recommended dosage regimen is 1 drop of 1.2 mg/ml twice daily. No comparative studies in humans between the 2 drugs have yet been published.

[Efficacy and tolerability of 2 presentations of eyedrops combining carteolol 2% and pilocarpine 2% in primary open-angle glaucoma and simple ocular hypertension].

The aim of the study was to compare 2 combinations of eye drops containing 2% carteolol and 2% pilocarpine: LCM 1010: ready to use eye drops CBS 341A: eye drops to be reconstituted (freeze-dried powder + solvent). Ninety-seven patients with primary open angle glaucoma or simple ocular hypertension were included in a randomized, double-blind multicentric study comparing 2 parallel groups of treatment. Intra-ocular pressure was greater than 21 mmHg with beta-blocker alone. One instillation of 2% carteolol-2% pilocarpine combination was given twice a day for one month. Before and after this treatment, intra-ocular pressure was measured at 9 am (12 hours after evening instillation) and at 11 am (2 hours after morning instillation). Both treatments reduced intra-ocular pressure by a comparable amount and there was no significant difference between groups at either measure: at 9 am: 2.11 +/- 2.39 mmHg (mean +/- SD) for LCM 1010 1.79 +/- 1.73 mmHg for CBS 341 A p = 0.25 at 11 am: 3.75 +/- 3.83 mmHg for LCM 1010 3.40 +/- 1.69 mmHg for CBS 341 A p = 0.42. Both eye drops were generally well tolerated. Efficacy and safety of ready to use eye drops 2% carteolol-2% pilocarpine combination proved to be comparable to that of eye drops to be reconstituted in the treatment of ocular hypertension poorly controlled by beta-blocker eye drops alone.

Bimatoprost/timolol

Bimatoprost/timolol, sold under the brand name Ganfort, is a medication for the treatment of certain conditions involving high pressure in the eyes, specifically open angle glaucoma and ocular hypertension. It is available as eye drops. It was approved for medical use in the European Union in May 2006. Medical uses Bimatoprost/timolol is used for the treatment of open angle glaucoma or ocular hypertension in people for whom single-component eye drops such as prostaglandin analogs or beta blockers are insufficient. Contraindications Because of the timolol component, which is a beta blocker, the drops are contraindicated in people with lung problems such as asthma or severe chronic obstructive pulmonary disease, or with heart problems such as sinus bradycardia (slow heartbeat), sick sinus syndrome, sino-atrial block, or severe atrioventricular block.

Timolol

In its eye drop form it is used to treat open-angle and, occasionally, secondary glaucoma. The mechanism of action of timolol is probably the reduction of the formation of aqueous humor in the ciliary body in the eye. It was the first beta blocker approved for topical use in treatment of glaucoma in the United States (1978). When used by itself, it depresses intraocular pressure (IOP) 18–34% below baseline within first few treatments. However, there are short-term escape and long-term drift effects in some people. That is, tolerance develops. It may reduce the extent of the diurnal IOP curve up to 50%. The IOP is higher during sleep. Efficacy of timolol in lowering IOP during the sleep period may be limited. It is a 5–10× more potent β-blocker than propranolol. Timolol is light-sensitive; it is usually preserved with 0.01% benzalkonium chloride (BAC), but also comes BAC-free. It can also be used in combination with pilocarpine, carbonic anhydrase inhibitors or prostaglandin analogs.

Pharmacology_Katzung

is associated with acute and painful increases of pressure, which must be controlled on an emergency basis with drugs or prevented by surgical removal of part of the iris (iridectomy). The open-angle form of glaucoma is a chronic condition, and treatment is largely pharmacologic. Because intraocular pressure is a function of the balance between fluid input and drainage out of the globe, the strategies for the treatment of open-angle glaucoma fall into two classes: reduction of aqueous humor secretion and enhancement of aqueous outflow. Five general groups of drugs—cholinomimetics, α agonists, β blockers, prostaglandin F2α analogs, and diuretics—have been found to be useful in reducing intraocular pressure and can be related to these strategies as shown in Table 10–3. Of the five drug groups listed in Table 10–3, the prostaglandin analogs and the β blockers are the most popular. This popularity results from convenience (onceor twice-daily dosing) and relative lack of adverse effects

Ocular hypertension

Ocular hypertension is the presence of elevated fluid pressure inside the eye (intraocular pressure), usually with no optic nerve damage or visual field loss. For most individuals, the normal range of intraocular pressure is between 10 mmHg and 21 mmHg. Elevated intraocular pressure is an important risk factor for glaucoma. One study found that topical ocular hypotensive medication delays or prevents the onset of primary open-angle glaucoma. Accordingly, most individuals with consistently elevated intraocular pressures of greater than 21mmHg, particularly if they have other risk factors, are treated in an effort to prevent vision loss from glaucoma. Pathophysiology The pressure within the eye is maintained by the balance between the fluid that enters the eye through the ciliary body and the fluid that exits the eye through the trabecular meshwork.

InternalMed_Harrison

Chronic angle-closure glaucoma and chronic open-angle glaucoma are usually asymptomatic. Only acute angle-closure glaucoma causes a red or painful eye, from abrupt elevation of intraocular pressure. In all forms of glaucoma, foveal acuity is spared until end-stage disease is reached. For these reasons, severe and irreversible damage can occur before either the patient or the physician recognizes the diagnosis. Screening of patients for glaucoma by noting the cup-to-disc ratio on ophthalmoscopy and by measuring intraocular pressure is vital. Glaucoma is treated with topical adrenergic agonists, cholinergic agonists, beta blockers, and prostaglandin analogues. Occasionally, systemic absorption of beta blocker from eyedrops can be sufficient to cause side effects of bradycardia, hypotension, heart block, bronchospasm, or depression. Topical or oral carbonic anhydrase inhibitors are used to lower intraocular pressure by reducing aqueous production. Laser treatment of the trabecular

Brimonidine/timolol

Brimonidine/timolol, sold under the brand name Combigan, is a fixed-dose combination medication eye drop indicated for the treatment of glaucoma. It is a combination of brimonidine (an α2 adrenergic agonist) and timolol (a β adrenergic blocker), in concentrations of 0.2% and 0.5% respectively. Both substances work by decreasing the synthesis of aqueous humor. Combigan is marketed and sold by Allergan. It has been approved by regulatory authorities in Europe, Canada, and the United States for reduction of intraocular pressure (IOP) in patients with glaucoma or ocular hypertension. Although clinical studies showed that the IOP-lowering effect was slightly greater (1-2 mmHg) with concomitant administration of 0.5% timolol twice daily and 0.2% brimonidine tartrate three times daily than with Combigan twice daily, the safety profile of latter was more favorable.

Brinzolamide

Brinzolamide (trade names Azopt, Alcon Laboratories, Befardin, Fardi Medicals, ) is a carbonic anhydrase inhibitor used to lower intraocular pressure in patients with open-angle glaucoma or ocular hypertension. Brinzolamide was approved as a generic medication in the United States in November 2020. Chemistry Brinzolamide is a carbonic anhydrase inhibitor (specifically, carbonic anhydrase II). Carbonic anhydrase is found primarily in erythrocytes (but also in other tissues including the eye). It exists as a number of isoenzymes, the most active of which is carbonic anhydrase II (CA-II). Indications Use for the treatment of open-angle glaucoma and raised intraocular pressure due to either excess aqueous humor production or inadequate drainage of the humor via the trabecular meshwork.

Steroid-Induced Glaucoma -- Treatment / Management

Medical management : medical management of this condition is similar to that of primary open-angle glaucoma. The agents which may be used include beta-blockers, prostaglandin analogs, alpha-2 agonists, and carbonic anhydrase inhibitors. Beta-blockers tend to be the first-line agents in this condition. [45]

Prognostic factors for hypotensive effects of isopropyl unoprostone in eyes with primary open-angle glaucoma.

It has been reported that isopropyl unoprostone, a prostaglandin-related compound, has potent effects in lowering intraocular pressure and that its hypotensive effect is an increase of uveoscleral outflow. In the present study, we investigated the clinical characteristics of the hypotensive effects of this novel antiglaucoma drug in 115 primary open-angle glaucoma (POAG) eyes. The mean intraocular pressure (+/- standard deviation) before the addition of isopropyl unoprostone to the current regimens was 21.3 +/- 4.4 mmHg. The values at 1 month, 3 months, and 6 months after treatment were, respectively, 20.2 +/- 3.9 mmHg, 19.4 +/- 3.4 mmHg, and 18.4 +/- 2.5 mmHg. In POAG, the outflow pressure difference (delta OP), which is determined as (pretreatment pressure - posttreatment pressure)/(pretreatment pressure - 10) x 100 (%), was reduced by more than 20% in 36 (31%) of 115 eyes, 35 (36%) of 97 eyes, and 33 (53%) of 62 eyes, respectively at 1, 3, and 6 months. We defined the "early success" group as eyes with a significant reduction in delta OP (> or = 20%) at 1-month posttreatment. To identify the prognostic factors related to the significant reduction in intraocular pressure occurring after the administration of this drug, we carried out a statistical analysis by logistic regression analysis. Statistical analysis revealed significant prognostic factors: history of cataract surgery (P = 0.0084) and pretreatment pressure levels (P = 0.0105) at 1-month posttreatment. Also, further statistical analysis showed a significant influence of pretreatment pressure levels (P = 0.0010) at 3 months posttreatment. Our study shows an interindividual difference in the responsiveness of hypotensive effects on POAG eyes and some prognostic factors (history of cataract surgery and pretreatment pressure levels) prior to the use of this drug.

Medication

For pain The main classes of painkillers are NSAIDs, opioids and local anesthetics. For consciousness (anesthetic drugs) Some anesthetics include benzodiazepines and barbiturates. For musculo-skeletal disorders The main categories of drugs for musculoskeletal disorders are: NSAIDs (including COX-2 selective inhibitors), muscle relaxants, neuromuscular drugs, and anticholinesterases. For the eye General: adrenergic neurone blocker, astringent. Diagnostic: topical anesthetics, sympathomimetics, parasympatholytics, mydriatics, cycloplegics. Antibacterial: antibiotics, topical antibiotics, sulfa drugs, aminoglycosides, fluoroquinolones. Antiviral drugs. Anti-fungal: imidazoles, polyenes. Anti-inflammatory: NSAIDs, corticosteroids. Anti-allergy: mast cell inhibitors. Anti-glaucoma: adrenergic agonists, beta-blockers, carbonic anhydrase inhibitors/hyperosmotics, cholinergics, miotics, parasympathomimetics, prostaglandin agonists/prostaglandin inhibitors, nitroglycerin.

Ciliary body

Alpha-adrenergic agonists work by decreasing production of fluid and increasing drainage. Brimonidine and Apraclonidine are two commonly prescribes alpha agonists for glaucoma treatment. Alphagan P uses a purite preservative, which is better tolerated those who have allergic reactions than the older BAK preservative in other eye drops. Furthermore, less selective alpha agonists such as [epinephrine] may decrease the production of aqueous humor through vasoconstriction of the ciliary body (only for open-angle glaucoma). Carbonic anhydrase inhibitors also decrease fluid production. They are available as eye drops (Trusopt and Azopt) and pills (Diamox and Neptazane). This may be helpful if using more than one type of eye medication.

[Initial combination therapy for primary open-angle glaucoma].

To study the efficacy and safety of initial combination therapy in patients with primary open-angle glaucoma (POAG). The study included 111 patients (161 eyes) with stages II-III b-c of POAG aged 46 to 89 years (mean age 70.8±8.5 years). In the test group, therapy began with a fixed combination of prostaglandin (PG) (latanoprost) and beta-blocker (BB) (timolol). In patients of the control group, POAG therapy began with administration of the analogue of prostaglandin (latanoprost). When the target IOP was not achieved, a second drug was added to the treatment - instillations of 0.5% solution of timolol maleate 2 times a day. In patients of the test group the treatment started with a combination of BB + PG, the target IOP in the 'worst' eyes was achieved in 33 cases (64%) in 1.5±0.6 visits, and in the 'best' eyes - in 17 cases (81%), in 1.2±0.4 visits. In the control group with a 'step-by-step' selection of antihypertensive therapy, the target IOP in the 'worst' eyes was achieved in 35 cases (59%), in 2.5±0.7 visits, and in the 'best' eyes - in 22 cases (76%), in 2.2±0.5 visits (p<0.05). In both study groups, there were no cases of drug withdrawal attributed to their side effects. Patients noted conjunctival hyperemia in 5% (4 eyes) and 7% (6 eyes) of cases in the test group and the control group, respectively (p>0.05). Hyperemia decreased significantly in 2 weeks of latanoprost administration or fixed combination and did not cause withdrawal. Initial combination therapy is possible in patients with newly diagnosed POAG in some clinical situations, namely in stages II-III POAG with high IOP, unavailability of regular observation of patients for various social and economic reasons, absence of somatic and local contraindications to individual components of the combined treatment, etc.

Dorzolamide

Medical uses Dorzolamide hydrochloride is used to lower excessive intraocular pressure in open-angle glaucoma and ocular hypertension. This drug is able to cross the cornea, reach the ciliary body of the eye, and produce systemic effects on the carbonic anhydrase enzyme within the eye. Side effects Ocular stinging, burning, itching and bitter taste. It causes shallowing of the anterior chamber and leads to transient myopia. As a second generation carbonic anhydrase inhibitor, Dorzolamide avoids systemic effects associated with first generation carbonic anhydrase inhibitors such as Acetazolamide, Methazolamide, and Dichlorphenamide. Pharmacodynamics It lowers IOP by about 20%. Carbonic Anhydrase can convert H2CO3 into HCO3 (bicarbonate) and H+. The H+ is then exchanged for sodium (Na) which allows you to make aqueous humor. By blocking carbonic anhydrase, the Na/H exchanger can't work, which will decrease Na in the cell and prevent aqueous humor production.

[Ocular hypotensive effect of systemic beta-blockers in patients with primary glaucoma and arterial hypertension].

to evaluate the ocular hypotensive efficacy of systemic beta-blockers in primary glaucoma patients suffering from arterial hypertension (AH). The study included 29 patients with POAG (58 eyes) aged from 47 to 83 years. Patients with stage I-III POAG received instillations of prostaglandin analogs and carbonic anhydrase inhibitors. All POAG patients also suffered from arterial hypertension and were prescribed selective beta-blockers (metoprolol, bisoprolol, or nebivalol) as monotherapy or as part of combination therapy (if the target arterial pressure had not been achieved under the initial treatment). After the start of oral beta-blockers therapy, the patients were re-examined at 2 and 4 weeks, 3 months, 6 months, and 1 year. A clinically significant reduction of IOP in the most seriously affected eye - by 3.3 mmHg (p<0.05), or 14% - occurred four weeks after the start of selective beta-blockers. Over three months of combination therapy, IOP in the 'worst' eye decreased by 4.4 mmHg (18.5%). At 1 year, IOP in the 'worst' eye was 6.2 mmHg (26%) lower than at baseline (p<0.05). Aged and senile patients with primary glaucoma usually suffer from polypathy (on average, they have 6.3±0.6 concurrent somatic diseases). To reduce the risk of polypharmacy and the frequency of side effects in the treatment of POAG and AH patients, it is advised that the treatment includes oral selective beta-blockers able to provide target levels of arterial pressure and IOP. In this study, oral beta-blockers in POAG and AH patients enabled IOP reduction as great as 18.5%-26% of baseline values over a 1-year follow-up period.

Carbonic anhydrase inhibitors as fourth drug in primary glaucomas: Is it worth it?

To evaluate the effectiveness of carbonic anhydrase inhibitors as the fourth drug regarding intraocular pressure (IOP) control in patients with primary glaucomas. Single-centre, prospective study. Twenty-five eyes from 25 patients with primary glaucomas treated concomitantly with a topical prostaglandin analogue, a β-blocker, an α-adrenergic agonist, and a carbonic anhydrase inhibitor. Patients followed at the Federal University of São Paulo were enrolled from August to November 2013 and were initially submitted to an ophthalmologic examination where the IOP was measured at 8 am, 10 am, and 12 pm. Afterward, patients underwent a 15-day washout of the carbonic anhydrase inhibitor and had their IOP measured again. Most patients were female, white, and with a mean age of 66.4 ± 9.7 years. The removal of the fourth drug had a statistically significant effect on the IOP peak (increase of 1.20 mm Hg, p < 0.01) and mean (increase of 1.23 mm Hg, p < 0.01), but it did not interfere significantly with morning fluctuation of the IOP (p = 0.83). After discontinuation of the fourth drug, the IOP increased ≥2 mm Hg in 32% of the patients, and there was a significant increase of the IOP (defined as an IOP change ≥20%) in only 5 patients (20%). Age older than 60 years was associated with 20% of the documented IOP change (R(2) = 0.19, p = 0.03). The removal of a fourth medication does not appear to have a clinically significant impact on IOP control in most patients with glaucoma. However, 32% of the patients experienced an IOP increase ≥2 mm Hg, with age older than 60 years being the only significant predictive factor.

[New medical treatments of glaucoma. New strategies?].

Several new classes of ocular hypotonia medications have recently become available. These include the topical treatments carbonic anhydrase inhibitors, the alpha-2 agonists, the prostaglandin analogues, and a fixed combination of beta-blockers and carbonic anhydrase inhibitors. With an equal or superior efficacy than beta-blockers, these new treatments must be reconsidered as first-line therapy in glaucoma. The long-term safety profile of antiglaucomatous drugs plays an important role in the new trends of medical treatment. These data, better known and detailed over time by clinical experience, are changing our habits and advancing therapeutic strategies for a more effective treatment, better suited to the individual, thus allowing the best quality of life possible.

Intraocular pressure changes in the contralateral eye after topical treatment: does an "ophthalmotonic consensual reaction" exist?

The existence of "ophthalmotonic consensual reaction," a contralateral change in intraocular pressure in the fellow eye induced by treatment of the first eye only, was suggested in 1924. Since then, the validity of this mechanism has been controversial. To assess intraocular pressure changes in the contralateral fellow eyes of patients treated with IOP-lowering medication in one eye, and investigate the existence of an ophthalmotonic consensual reaction. The study population included 38 patients with newly diagnosed bilateral ocular hypertension or early open angle glaucoma. One eye of each patient was randomly treated with one of five compounds: prostaglandin analogues, beta-blockers, alpha-2 agonists, carbonic anhidrase inhibitors and a combination therapy: dorzolamide hydrochloride-timolol maleate (Cosopt, Merck Sharpe & Dohme). The eye with the higher baseline IOP was selected to be the treated eye. After 3 weeks a masked examiner measured the IOP in both the treated and untreated eye. Mean IOP of the treated eyes at baseline was 26.1 +/- 4.2 mmHg and at follow-up 20.2 +/-2.9 mmHg, a reduction of IOP from baseline of -6 +/- 3.8 mmHg, a mean percent reduction of -22 +/- 10.1%. In the contralateral eyes, the mean IOP at baseline was 24.2 +/- 3 mmHg and 23.1 +/- 3.1 mmHg at follow-up; IOP reduction from baseline was -1.2 +/- 1.8 mmHg, or mean percent reduction -4.7 +/- 7.1%. A major contralateral IOP decrease was seen only in the beta-blockers and the combination (Cosopt) treatment groups (-6.1 +/- 8.3% and -12.3 +/- 8.3% mean percent reduction, respectively, P < 0.05). The contralateral eyes in the prostaglandin analogues, CAI or alpha2-agonist groups showed only a small change in IOP (-2.6 +/- 4.6%, -3.2 +/- 2.6%, +0.7 +/- 3.3%, mean percent reduction, respectively, P < 0.05). The existence of an ophthalmotonic consensual reaction was not supported.

Intraocular pressure-lowering combination therapies with prostaglandin analogues.

Intraocular pressure (IOP) reduction is currently the only therapeutic approach demonstrated to preserve visual function in patients with glaucoma. The first line of glaucoma treatment consists of topical IOP-lowering medications, usually initiated as monotherapy. A significant proportion of patients require more than one medication to reach a target IOP at which optic nerve damage will not progress. As prostaglandin analogues (PGAs) are the most effective class for reducing IOP, one of the other commonly used classes (β-adrenoceptor antagonist [β-blocker], carbonic anhydrase inhibitor or α(2)-adrenoceptor agonist) is frequently combined with a PGA. In the last decade, the use of fixed combinations containing two medications in a single bottle has steadily increased. Fixed combinations have the potential to simplify the dosing regimen, increase patient adherence, avoid the washout effect of the second drop on the first medication instilled, decrease exposure to preservatives and, sometimes, reduce the cost of treatment. Clinical trials have evaluated PGA-based fixed combinations versus unfixed combinations (individual components administered concomitantly) or versus individual monotherapies; however, any advantage that the fixed combinations may have in terms of IOP-lowering efficacy is still debated. For these reasons, the PGA-based fixed combinations are not approved by regulatory authorities in some countries, such as the US. We review the published studies evaluating the efficacy and tolerability of the IOP-lowering unfixed and fixed combination therapies with PGAs. Regarding unfixed combinations, the review shows that α(2)-adrenergic agonists-PGA and carbonic anhydrase inhibitor-PGA combinations seem to be at least as effective at reducing IOP as the β-blocker-PGA combinations. As for the fixed combinations, the review shows that the three PGA-timolol fixed combinations are more effective than their component medications used separately as monotherapy and are better tolerated than the three respective prostaglandins. The three PGA-timolol fixed combinations are less effective at reducing IOP than the unfixed combinations but are better tolerated. The advantage of the fixed combinations in terms of patient adherence and persistence is supported by a very small number of studies and remains to be more accurately determined. Most studies, but not all, seem to show that PGA-timolol fixed combinations are more effective than other available β-blocker fixed combinations (dorzolamide-timolol fixed combinations) at reducing IOP and are similarly tolerated.

Uveitis–Glaucoma–Hyphema syndrome

Treatment Initially, topical and systemic medication to control inflammation and raised IOP is appropriate, but the definitive treatment is an IOL reposition or exchange. Topical corticosteroids may be used to control anterior inflammation. Raised IOP can be lowered using topical and systemic anti-glaucoma medications such as prostaglandin analogs, beta-adrenergic antagonists, alpha-adrenergic agonists, and carbonic anhydrase inhibitors etc. History The UGH Syndrome was originally described by Ellingson in 1978 and classically included uveitis, glaucoma, and hyphaema in the setting of an anterior chamber IOL. References Glaucoma Disorders of iris and ciliary body Syndromes affecting the eyes

Peripheral vascular disease - a new vascular disease associated with normal tension glaucoma: a case report.

Normal-tension glaucoma is known as a multifactorial optic neuropathy. A number of lines of evidence suggested that vascular factors played a significant role in the development of normal-tension glaucoma. The mechanisms underlying the abnormal ocular blood flow in normal-tension glaucoma are still not clear. Peripheral vascular disease seems to be associated with glaucoma populations independent of other cardiovascular risk factors. We found this presentation, for the first time, to our knowledge, as another probable vascular abnormality related to our patient with normal-tension glaucoma, although it is necessary to confirm its pathological effect in future studies. Our patient was a 48-year-old Spanish man without any personal and family history of interest except for circulatory problems of the lower limbs with repetitive ulcers at the frontal and lateral aspects of his legs. His chief complaint was vision loss when he came to consult us. In exploration, his best corrected visual acuity was 20/20 in both eyes; initial intraocular pressure in the right eye was 14-16 mmHg and in the left eye was 16-18 mmHg, with a mild sclerosis of the lens in slit-lamp examination. No inflammation or pigmented lesion was detected in the anterior chamber. Open angle confirmed by Goldman four quadrants gonioscopy. Funduscopic examination revealed a vertical cup disc ratio of 0.6 in the right eye and 0.8 in the left eye. The patient's neuroretinal rim was normal in the right eye, and superior thinning in the left eye was determined. Examination of the patient's visual field showed inferior mild probable nasal scotoma in the right eye and an inferior deep arcuate scotoma defect in the left eye. His optical coherence tomography examination revealed thinning of the peripapillary nerve fiber layer thickness in the left eye and superior loss of macular retinal ganglion cells in the left eye. Normal intraocular pressure values were measured on the intraocular pressure curve without treatment (maximum value, 18-20 mmHg), discarding higher intraocular pressures measured out of office. Ultrasonic pachymetry measured 515/520 μm, and normal intraocular pressure measured with a PASCAL tonometer ruled out probable corneal biomechanical underestimations. The patient's polysomnography study was normal and excluded sleep apnea syndrome. The patient's serial mean blood pressure was normal, especially in the lower limbs (mean value, 125/70 mmHg), ruling out the possibility of systemic hypotension. Thyroidal and coagulation abnormalities, autoimmune disease, and inflammatory disease were excluded. Normal immunologic study and normal vascular biopsy were observed, as well as normal brain magnetic resonance imaging and a normal carotid vascular study. The primary diagnosis was moderate medium peripheral arterial disease in the lower limbs, which was confirmed by echography after ruling out other probable vascular abnormalities related to normal-tension glaucoma. After ruling out other systemic diseases and vascular abnormalities related to normal-tension glaucoma, we found peripheral arterial disease as a probable vascular abnormality related to normal-tension glaucoma in our patient. To our knowledge, this is the first time such a case has been reported. Thus, further research is needed to determine the relevance of these results to the general population.

How prostaglandins have changed the medical approach to glaucoma and its costs: an observational study of 2228 patients treated with glaucoma medications.

The aim of the present study was to investigate how the medical treatment of glaucoma changed between 1997 and 2002, since the advent of prostaglandin derivatives, with regard to drug prescriptions and pharmaceutical costs. A study was made of medical prescriptions for 2228 patients with glaucoma and/or ocular hypertension, in order to investigate the following: (i) the antiglaucoma drugs most commonly prescribed in 1997 and 2002, and any differences between the drugs prescribed in these 2 years; (ii) the number of drugs used per patient in 1997 and 2002, respectively, and (iii) any increase in the prescribing of antiglaucoma drugs and their relative costs from 1997 to 2002. From 1997 to 2002 there was a sharp drop in the prescribing of beta-blockers (79% in 1997 and 55% in 2002). A marked increase in the use of prostaglandin derivatives (0% in 1997 and 18% in 2002) was registered and a marked increase in the prescribing of carbonic anhydrase inhibitors (5% in 1997 and 14% in 2002) was also noted. From 1997 to 2002 there was a trend towards drug addition rather than substitution, so that the number of drugs used per patient increased. The number of patients treated increased enormously (by 98%) from 1997 to 2002. The cost of medical therapy from 1997 to 2002 rose dramatically, with an increase of 148.9% per patient. The availability of prostaglandin derivatives has strongly influenced the medical approach to glaucoma. This class of drugs will soon become the type most commonly prescribed for patients with glaucoma and/or ocular hypertension. The increased number of treatments also suggests that the approach of ophthalmologists towards these diseases has changed. Ocular hypertension, as well as glaucoma, is now treated more aggressively. Given the increase in the prescription of prostaglandin derivatives, the pharmaceutical cost of treatment has risen dramatically.

Glaucoma

still today - despite numerous new innovations in diagnostics - is considered the gold standard of determining this crucial pathogenic factor. In the late 20th century, further pathomechanisms beyond elevated IOP were discovered and became the subject of research like insufficient blood supply – often associated with low or irregular blood pressure – to the retina and optic nerve head. The first drug to reduce IOP, pilocarpine, was introduced in the 1870s; other major innovations in pharmacological glaucoma therapy were the introduction of beta blocker eye drops in the 1970s and of prostaglandin analogues and topical (locally administered) carbonic anhydrase inhibitors in the mid-1990s.. Early surgical techniques like iridectomy and fistulating methods have recently been supplemented by less invasive procedures like small implants, a range of options now widely called MIGS (micro-invasive glaucoma surgery).

Carbonic anhydrase inhibitor

Methazolamide is also a carbonic anhydrase inhibitor. It has a longer elimination half-life than acetazolamide and is less associated with adverse effects to the kidney. Dorzolamide is a sulfonamide and topical carbonic anhydrase II inhibitor. It is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension and who are insufficiently responsive to beta-blockers. Inhibition of carbonic anhydrase II in the ciliary processes of the eye decreases aqueous humor secretion, presumably by slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport.


Technically the patient is in a grade II hemorrhage according to the ATLS classification, in principle this means a loss of between 750 and 1500mL of blood and the indicated action is resuscitation with crystalloids; however, in the guidelines for the care of severe polytraumatized patients, the early use of blood products is increasingly recommended, especially in borderline cases like this one, and in young patients, who may not be able to translate the severity of the blood loss until it becomes much more significant. I would therefore hesitate between options 1 and 2.

An 18-year-old man arrives at the hospital emergency department transported by a basic life support unit. He has been hit by a car while riding a bicycle. On arrival he has a heart rate of 115 bpm, a blood pressure of 110/75 mmHg, a palpable radial pulse, a capillary refill of 2.5 seconds and a respiratory rate of 25 rpm. What do these data tell us:

The patient has lost 15 to 30% of blood volume and requires volume replacement.

She has lost more than 30% of volemia and needs volume and blood replacement.

He has lost more than 40% of blood volume and will require surgical treatment.

Has lost more than 50% of volemia and requires volume and blood replacement.

Surgery_Schwartz

blood volume. However, substantial volumes of blood may be lost before the classic clinical manifestations of shock are evident. Thus, when a patient is significantly tachycardic or hypotensive, this represents both significant blood loss and physiologic decompensation. The clinical and physiologic response to hemorrhage has been classified according to the magnitude of volume loss. Loss of up to 15% of the circulat-ing volume (700 to 750 mL for a 70-kg patient) may produce little in terms of obvious symptoms, while loss of up to 30% of the circulating volume (1.5 L) may result in mild tachycar-dia, tachypnea, and anxiety. Hypotension, marked tachycardia (i.e., pulse greater than 110 to 120 bpm), and confusion may not be evident until more than 30% of the blood volume has been lost; loss of 40% of circulating volume (2 L) is immedi-ately life threatening and generally requires operative control of bleeding (Table 5-5). Young healthy patients with vigor-ous compensatory mechanisms may

Hypovolemic shock

Class 1: Volume loss up to 15% of total blood volume, approximately 750 mL. Heart rate is minimally elevated or normal. Typically, there is no change in blood pressure, pulse pressure, or respiratory rate. Class 2: Volume loss from 15% to 30% of total blood volume, from 750 mL to 1500 mL. Heart rate and respiratory rate become elevated (100 BPM to 120 BPM, 20 RR to 24 RR). Pulse pressure begins to narrow, but systolic blood pressure may be unchanged to slightly decreased. Class 3: Volume loss from 30% to 40% of total blood volume, from 1500 mL to 2000 mL. A significant drop in blood pressure and changes in mental status occur. Heart rate and respiratory rate are significantly elevated (more than 120 BPM). Urine output declines. Capillary refill is delayed.

Volume expander

A volume expander is a type of intravenous therapy that has the function of providing volume for the circulatory system. It may be used for fluid replacement or during surgery to prevent nausea and vomiting after surgery. Physiology When blood is lost, the greatest immediate need is to stop further blood loss. The second greatest need is replacing the lost volume. This way remaining red blood cells can still oxygenate body tissue. Normal human blood has a significant excess oxygen transport capability, only used in cases of great physical exertion. Provided blood volume is maintained by volume expanders, a rested patient can safely tolerate very low hemoglobin levels, less than 1/3 that of a healthy person.

Shock Resuscitation -- Indications

In Class 2 shock, the patient has lost 750 mL to 1500 mL of blood (between 15% and 30% of total blood volume) and is beginning to become symptomatic. They may start to appear more pale or diaphoretic, with mild tachycardia (100-120 bpm), the respiratory rate may increase slightly (20-30 bpm), and their urine output may drop slightly (20-30 mL/hr). It is important to note that even outside the realm of shock management, urine output remains the single most important indicator for monitoring fluid status in a patient. Additionally, blood pressure cannot be adequately relied upon to detect the beginning of shock, as the body’s compensatory mechanisms will keep blood pressure typically within normal limits until up to 30% of total blood volume has already been lost. Finally, the Class 2 shock patient may demonstrate a slight decrease in pulse pressure, which may be the first sign of the body failing to compensate for the sudden blood loss.

Efficacy of acute normovolemic hemodilution assessed as a function of fraction of blood volume lost.

It has been recommended that intraoperative acute normovolemic hemodilution (ANH) be considered for patients expected to experience surgical blood loss of 20% or more of their blood volume. Previous mathematical analyses have not evaluated the potential efficacy of ANH in terms of fraction of blood volume lost. Since decrease of oxygen-carrying capacity is a function of erythrocyte loss relative to blood volume, the purpose of this analysis was to provide an assessment of ANH applicable to all blood volumes and to determine whether this recommendation is appropriate. Equations were developed to describe the fractional blood volume loss (blood volume loss/blood volume; VReM/VBld) required to reduce hematocrit below a "trigger" hematocrit with maintenance of isovolemia. This is also the minimum fractional blood volume loss required for initial erythrocyte savings by any conservation technique. Equations were also developed to describe the fractional surgical blood volume loss for which ANH will obviate the need for transfusion of erythrocytes from any source other than those removed by ANH, and the fractional surgical blood volume loss required for ANH to save a defined volume of erythrocytes. Acute normovolemic hemodilution can extend the allowable fractional surgical blood loss before erythrocyte transfusion is required. The VRem/VBld required to initiate erythrocyte savings is approximately 0.5-0.9. The efficacy of ANH in terms of erythrocytes saved cannot be expressed as a function of the fractional blood volume lost alone. To save 1 unit of erythrocytes requires a fractional surgical blood loss of approximately 0.7-1.2 for the usual surgical patient when the transfusion trigger hematocrit is 0.18-0.21. This analysis suggests that surgical blood loss should be 0.50 or more for ANH to begin to "save" erythrocytes and 0.70 or more of the patient's blood volume for ANH to save 1 unit erythrocytes, for the usual surgical patient with an initial hematocrit of 0.32-0.36 and a transfusion "trigger" hematocrit (the value at which transfusion is initiated) of 0.18-0.21.

Volume expander

The body detects the lower hemoglobin level, and compensatory mechanisms start up. The heart pumps more blood with each beat. Since the lost blood was replaced with a suitable fluid, the now diluted blood flows more easily, even in the small vessels. As a result of chemical changes, more oxygen is released to the tissues. These adaptations are so effective that if only half of the red blood cells remain, oxygen delivery may still be about 75 percent of normal. A patient at rest uses only 25 percent of the oxygen available in their blood. In extreme cases, patients have survived with a hemoglobin level of 2 g/dl, about 1/7 the normal, although levels this low are very dangerous.

Bleeding

Class III Hemorrhage involves loss of 30-40% of circulating blood volume. The patient's blood pressure drops, the heart rate increases, peripheral hypoperfusion (shock) with diminished capillary refill occurs, and the mental status worsens. Fluid resuscitation with crystalloid and blood transfusion are usually necessary. Class IV Hemorrhage involves loss of >40% of circulating blood volume. The limit of the body's compensation is reached and aggressive resuscitation is required to prevent death.

Shock Resuscitation -- Indications

In Class 3 hemorrhagic shock, the patient has lost 1500-2000 mL of blood (30-40% total blood volume), they will be clearly symptomatic, confused and will be tachycardic (120-140 bpm), tachypneic (30-40 breaths/min), with blood pressure and pulse pressure decreased causing a drop in renal perfusion (urine output decreased to 5-15 mL/hr). Class 4 shock is the most severe case with acute blood loss of over 2000 mL (or over 40% total blood volume). The patient’s heart rate will be tachycardic, over 140 bpm, with nonpalpable or thready peripheral pulses. Their respiratory rate will have increased to over 35 breaths/min, and their blood pressure and pulse pressure will subsequently be severely decreased. Urine output will be negligible, and symptomatically they will be more lethargic with a likely altered mental status.

[The hemodynamic effects of various hydroxyethyl starch solutions in heart surgery patients].

Blood conservation is gaining more and more interest because of the increasing risks involved in homologous blood transfusions. Acute normovolemic hemodilution (ANH) is becoming an established technique even in cardiac surgery patients. The "optimal" kind of volume replacement, however, is still controversial. Thus, this study was carried out to investigate the hemodynamic response of 6 different hydroxyethyl starch (HES) solutions as volume replacement. METHODS. In 60 patients undergoing elective aortocoronary bypass surgery, acute, preoperative hemodilution was performed (10 ml/kg) and HES with different concentrations, molecular weight, and substitution was infused according to a randomized sequence: 1. 6% HES 450,000/0.7; 2. 10% HES 200,000/0.5; 3. 3% HES 200,000/0.5%; 4. 6% HES 40,000/0.5; 5. 6% HES 200,000/0.5; 6. 6% HES 200,000/0.62. All patients were monitored using a new pulmonary artery catheter that allows measurement of the right ventricular ejection fraction (RVEF), right ventricular enddiastolic volume (RVEDV), and right ventricular end systolic volume (RVESV) in addition to standard hemodynamic parameters. RESULTS. Immediately after finishing ANH the typical hemodynamic changes of hemodilution (HD) were apparent (decrease in peripheral resistance and increase in cardiac index (CI]. All 6 solutions investigated were effective in hemodynamic stabilization (no changes in mean arterial pressure (MAP), filling pressures (PCP, RAP), or heart rate (HR]. Forty min after ANH, however (before beginning extracorporeal circulation (ECC], there were significant differences between the groups: in groups 3 and 4 the increase in CI had already disappeared, and SVI in group 3 was even lower than the baseline values (-8%). In the other groups, a higher CI level remained even 40 min after ANH, which was most pronounced in groups 2 (+40%) and 5 (+43%). Right ventricular performance was not changed by ANH (RVEF unchanged in all groups). Forty min after hemodilution RVEDVI (-8%) and RVESVI (-16%) decreased significantly only in group 4, whereas in the other groups these parameters were still elevated. The most pronounced positive fluid balance after the end of ECC was found in group 4 (+850 ml); in these patients paO2 decreased significantly (-150 mmHg). CONCLUSIONS. The guarantee of stable hemodynamic conditions is a prerequisite when performing ANH in coronary surgery patients. The different physiochemical attributes of various HES solutions seem to be important, thus influencing their hemodynamic response. In this study, low-concentration (3% HES 200/0.5) and low-molecular (6% HES 40/0.5) HES solutions were less effective in stabilizing hemodynamics until the beginning of ECC. Additionally, their negative influence on fluid balance during ECC, followed by a deterioration in pulmonary function led to the conclusion that other solutions are preferable; in particular, 10% HES seems to be of advantage in these situations.

Don't Cry for Me, Albuquerque

Mary is rushed to the hospital; she has lost a large volume of blood, is unconscious and goes into cardiac arrest in the ambulance; though she is revived, she does not regain consciousness due to low blood volume. Marshall is the first to arrive as she is being wheeled into emergency, and he pleads with her not to die; after being barred from coming into the trauma room with her, he crumples to the floor in tears as Stan arrives, sobbing that she still wasn't breathing.

Hypovolemia

Medical personnel should immediately supply emergency oxygen to increase efficiency of the patient's remaining blood supply. This intervention can be life-saving. The use of intravenous fluids (IVs) may help compensate for lost fluid volume, but IV fluids cannot carry oxygen the way blood does—however, researchers are developing blood substitutes that can. Infusing colloid or crystalloid IV fluids also dilutes clotting factors in the blood, increasing the risk of bleeding. Current best practice allow permissive hypotension in patients suffering from hypovolemic shock, both avoid overly diluting clotting factors and avoid artificially raising blood pressure to a point where it "blows off" clots that have formed. Hospital treatment Fluid replacement is beneficial in hypovolemia of stage 2, and is necessary in stage 3 and 4. See also the discussion of shock and the importance of treating reversible shock while it can still be countered.

Hypovolemia

Stages Untreated hypovolemia can lead to shock (see also: hypovolemic shock). Most sources state that there are 4 stages of hypovolemia and subsequent shock; however, a number of other systems exist with as many as 6 stages. The 4 stages are sometimes known as the "Tennis" staging of hypovolemic shock, as the stages of blood loss (under 15% of volume, 15–30% of volume, 30–40% of volume and above 40% of volume) mimic the scores in a game of tennis: 15, 15–30, 30–40 and 40. It is basically the same as used in classifying bleeding by blood loss. The signs and symptoms of the major stages of hypovolemic shock include: Treatment Field care The most important step in treatment of hypovolemic shock is to identify and control the source of bleeding. Medical personnel should immediately supply emergency oxygen to increase efficiency of the patient's remaining blood supply. This intervention can be life-saving.

[Control of the ratio of the flow rate of the substitution fluid to the blood removal rate during preoperative normovolemic hemodilution].

Twenty-one patients (mean age 46 +/- 13 years) due to undergo abdominal or ENT surgery, presumed to give rise to an important blood loss were included in this study. None had any contra-indication to the use of normovolaemic haemodilution (NH). Mean initial haematocrit was 40.3 +/- 1.8%. Their estimated total blood volume was 4,867 +/- 857 ml. The patients were anaesthetized with thiopentone, fentanyl, vecuronium or atracurium. Maintenance was carried out with isoflurane (0.5% during NH). Usual haemodynamic monitoring was used throughout. The required haematocrit was decided on before starting NH. The amount of blood to be removed was calculated with usual mathematical formulae. A radial artery cannula (n = 7), or a subclavian or femoral venous cannula (n = 14) was used to remove blood, which was collected within a bag containing CPC-adenine. Six % hydroxyethyl starch (Elohes) was given through a short venous cannula some distance from the first one. An antiparallel double line set in a roller pump was used to carry out the NH. A mean 1,341 +/- 405 ml of blood were withdrawn so as to reach a mean haematocrit of 30.6 +/- 2.4%. NH was completed within 17 +/- 6 min. No major haemodynamic changes occurred during the procedure. No significant differences were observed between expected and observed final haematocrits. There was no effect of the volume of blood withdrawn on the error of haematocrit prediction (0.5 +/- 0.3%). However, a higher rate of blood removal could increase this error. This easy-to-use device seems to provide fast and identical rates of blood removal and replacement. The expected haematocrit may thus be reached reliably, even if this must be checked for the sake of safety.

Hemorrhage -- Pathophysiology

In a healthy adult, there is an average of 4.5 to 5.5 liters or 70 to 90 ml/kg of blood circulating at any given time. Most adults can tolerate losing up to 14% of their blood volume without physical symptoms or deviations in their vital signs. The severity of hemorrhage is divided into a class system organized by the percent of blood volume loss. Up to 15% of blood volume loss classifies as a Class I hemorrhage. The patient is generally asymptomatic, and vital signs are within normal limits. Class II hemorrhage is a loss of 15 to 30% of total blood volume. Common manifestations include complaints of nausea and fatigue. On physical exam, there will be pallor and cooling of the extremities. Vital signs will start to deviate from normal, with tachycardia being the first vital sign to increase (100 to 120 beats per minute), followed by an increased respiratory rate (20-24 breaths per minute). Class III hemorrhage is 30 to 40% of total blood volume loss. Common manifestations include delayed capillary refill (greater than two seconds) and changes in mental status. Drastic blood pressure deviations (less than 90 mm Hg) are generally not seen until 30% of the blood volume is lost. Vital signs may reflect a systolic less than 90 mmHg or 20 to 30% of original measurement; HR is greater than 120; changes in mental status; and narrow pulse pressure (less than 25 mm Hg). These changes represent the body attempting to maintain perfusion to the vital organs by constricting peripheral blood vessels. Class IV hemorrhage is defined as greater than 40% of total blood volume loss. There is commonly a lack of urine output, absent peripheral pulses, and further deviations in vital signs. Severe hemorrhaging can lead to shock, which occurs when the blood loss becomes significant enough that it is unable to meet the oxygen demands of the tissue. Cellular aerobic metabolism shuts down, and anaerobic metabolism begins, leading to the production of lactic acid and, ultimately, metabolic acidosis. [10] The risk is very high for organ failure, coma, and death, absent the timely implementation of life-saving interventions.

Hemodynamics

Hemodilution can be normovolemic, which implies the dilution of normal blood constituents by the use of expanders. During acute normovolemic hemodilution (ANH), blood subsequently lost during surgery contains proportionally fewer red blood cells per milliliter, thus minimizing intraoperative loss of the whole blood. Therefore, blood lost by the patient during surgery is not actually lost by the patient, for this volume is purified and redirected into the patient. On the other hand, hypervolemic hemodilution (HVH) uses acute preoperative volume expansion without any blood removal. In choosing a fluid, however, it must be assured that when mixed, the remaining blood behaves in the microcirculation as in the original blood fluid, retaining all its properties of viscosity. In presenting what volume of ANH should be applied one study suggests a mathematical model of ANH which calculates the maximum possible RCM savings using ANH, given the patients weight Hi and Hm.

[First aid and initial medical care in injuries of the large blood vessels].

Nowhere as in emergency medicine results of a well done first aid can be more obvious as in the cases of big blood vessels injuries. Properly done first aid and first medical aid at big blood vessels injuries save the life of the patient. The following example is the case of MM patient The patient was received in the Emergency ward after an explosive injury of the big artery vessels and badly done first aid and be was without any signs of life. The patient was treated with: Adrenalin hydrochloride 1 ml intracardial Hydrocortisone amp a 1000 mg i.v. Sol Haemaccel 3 x 500, o ml i.v. Sol Hartman 3 x 500 ml i.v. Na-bicarbonate amp a 40 mg i.v. (2 x 20 mg) 9 bottles of fresh blood (300 ml each) After the intensive cardiopulmonal reanimation the patient after 3 hours he was in a stable general condition and sent to the operation theatre. For proper first aid the methods and activities are very simple but they should be known and implemented. In the opposite case a patient can lose all the blood and die in a hemorrhagic state.

Hypovolemic shock

Class 4: Volume loss over 40% of total blood volume. Hypotension with narrow pulse pressure (less than 25 mmHg). Tachycardia becomes more pronounced (more than 120 BPM), and mental status becomes increasingly altered. Urine output is minimal or absent. Capillary refill is delayed.

[The demand for blood in open-heart surgery (author's transl)].

Because of the continous increase of utilization of open heart surgery, whenever possible a more conservative use of blood is desirable. During 1977, 262 consecutive patients were operated upon using the hemodilution technique of cardiopulmonary bypass. Thirtyone operative deaths occurred (11.8%) and were not related to lack of blood administration. Mean hematocrit values were 32.4% two hours after surgery and between 31 and 32.5% in the following postoperative course. Hemoglobin concentration averaged from 9.9 to 10.4 g/100 ml during the first postoperative week. The estimated amount of blood transfused averaged 872 +/- 66 ml (+/- SE) per patient. Sixtyone patients (23%) didn't receive any transfusion. A conservative attitude towards blood administration is justified by transfusion related many risks and by the current shortage of blood.

[Compensation for circulating blood volume in fatal blood loss].

Despite the extended potentials of modern medicine, noncompensated blood loss remains one of the leading causes of death in the able-bodied population all over the world. At present, there is no uniform policy of transfusion maintenance and intensive care in victims with severe decompensated blood loss. The purpose of the study was to assess the results of compensation for acute blood loss in victims with concomitant injury and wounds at various sites, which were attended by the loss of a circulating blood volume (CBV) with the use of new technologies. The authors retrospectively assessed the specific features of the course of anesthesia and compensation for blood loss in 66 male victims (mean age 37 +/- 1.5 years) with concomitant injury and various wounds complicated by acute CBV loss. CBV was compensated for by the currently available infusion media; globular blood volume deficit was restored via intraoperative instrumental reinfusion of autoblood and donor blood. The proposed procedure for infusion-transfusion therapy made it possible to stabilize the patient's condition and to perform emergency surgical treatment in victims with fatal blood loss. Total mortality in the chosen intensive care modality was 62.1%.

Volume therapy in the critically ill: is there a difference?

There are still several concerns about the extensive and prolonged use of hydroxyethylstarch solution (HES) in critically ill patients. The effects of volume replacement with HES over 5 days on hemodynamics, laboratory data, and organ function were compared with volume therapy using human albumin (HA). Prospective, randomized study. Clinical investigations on a surgical intensive care unit (ICU) of a university hospital. 150 traumatized patients (injury severity score > 15) and 150 postoperative patients with sepsis were analyzed. Either 10% low-molecular weight HES (HES-trauma, n = 75; HES-sepsis, n = 75) or 20% HA (HA-trauma, n = 75; HA-sepsis, n = 75) was given for 5 days to maintain the pulmonary capillary wedge pressure (PCWP) between 12 and 15 torr. The entire management of therapy of the patients was performed by physicians who were not involved in the study and blinded to the infusion regimen. In addition to extensive cardiorespiratory monitoring, several routine laboratory parameters for assessing pulmonary, renal, hepatic, and coagulation function were analyzed from arterial blood samples on the day of admission to the ICU and on the day of sepsis diagnosis, respectively ("baseline" value) and daily over the following 5 days. Mortality during and after the study did not differ significantly between the infusion groups. There were also no differences between the incidence of pulmonary, renal, or hepatic failure in the two subgroups. Mean arterial pressure, heart rate, and PCWP were similar in both subgroups, whereas cardiac index, oxygen delivery index, oxygen consumption index, and the ratio between the partial pressure of oxygen in arterial blood and fractional inspired oxygen were higher in the HES- than in the HA-treated groups. Standard coagulation parameters did not differ, albumin concentration increased significantly in both HA groups, and lactate concentrations decreased only in the HES-sepsis patients (from 2.8 +/- 0.5 to 1.5 +/- 0.4 mg/dl). Volume replacement using albumin was significantly (p < 0.001) more costly than therapy with HES. Volume therapy with 10% HES for 5 days in the ICU patient showed no disadvantages compared with an infusion regimen using 20% albumin. Volume replacement using HES may even be associated with improved hemodynamics. HES appears to be a valuable and significantly cheaper alternative to albumin--even for prolonged volume therapy in the critically ill patient.

[A case of acute right ventricular infarction and life-saving right ventricular assistance following emergency coronary revascularization and resection of a left ventricular aneurysm--discussion of indication and proper assist flow volume].

Right ventricular assistance (RVA) using centrifugal pump in combination with IABP was used to treat a patient who was difficult to wean from a cardiopulmonary bypass following emergency coronary revascularization and resection of a ventricular aneurysm performed to treat acute right ventricular infarction due to a PTCA complication. After 131 hours of RVA at 3.2 to 4.8 l/min, it was possible to remove the pump. No heparin was administered during this time, changing the pump head twice, was used for 64 and 50 hour period, no thrombi were detected either time. After being weaned from RVA, the patient developed severe respiratory dysfunction, but on the 10th postoperative day (POD) IABP was weaned, and on the 13th POD the artificial respirator was withdrawn. The results of the postoperative cardiac catheterization were favorable, the patient was discharged on the 57th POD, and has returned to society at the present time. The indications for RVA include a central venous pressure > 20 mmHg and a cardiac index < 1.8 l/min/m2, and tissue perfusion pressure and general preoperative condition should severe as guides. The higher the assisted flow volume the more efficacious in relieving ventricular load, but, since there is a limit to how much the left ventricle and lungs can withstand, it should not exceed levels which ensure the maintainance of cardiac output and tissue perfusion pressure.

[Preoperative normvolemic hemodilution in heart surgery. Pulmonary changes with the use of new technics].

Interest in preoperative hemodilution (HD) has intensified perceptibly again, because of the increasing risk of adverse reactions to donor blood. However, in coronary surgery patients the use of HD is still the subject of controversy, as it may possibly influence organ function and especially lung water content. New techniques, including membrane oxygenation, extracorporeal circulation (ECC) with only "partial" bypass due to 2-stage cannulation, and hemoconcentration with cell separators, have significantly modified patient management in the field of cardiac surgery. Therefore, the influence of moderate hemodilution (12 ml/kg) on extravascular lung water (EVLW) was investigated under these conditions in 45 patients with coronary artery disease. Volume replacement was performed either with hydroxyethyl starch solution (HD-HES group, n = 15, ratio of replacement 1:1) or with Ringer's lactate (HD-RL-group, n = 15, ratio 2.5:1); 15 patients not subjected to HD served as controls. ECC was carried out with membrane oxygenators only in partial bypass. Both during and after ECC, blood was concentrated by means of a cell-saving system allowing separation and reinfusion of the red cells while the plasma is discarded. EVLW was measured using a double-indicator dilution technique with indocyanine green. Starting from comparable baseline values, EVLW was not significantly changed by hemodilution. After ECC, however, the HD-RL group showed a significant increase in lung water content (means: +2.49 ml/kg equal 42.6%), whereas this was not significantly changed in the other groups. By 5 h after ECC, the lung water content had returned to baseline values and no more differences could be observed between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Blunt trauma

Recently, criteria have been defined that might allow patients with blunt abdominal trauma to be discharged safely without further evaluation. The characteristics of such patients include: absence of intoxication no evidence of lowered blood pressure or raised pulse rate no abdominal pain or tenderness no blood in the urine. To be considered low risk, patients would need to meet all low-risk criteria. Treatment When blunt trauma is significant enough to require evaluation by a healthcare provider, treatment is typically aimed at treating life-threatening injuries, which requires ensuring the patient is able to breathe and preventing ongoing blood loss. If there is evidence that the patient has lost blood, one or more intravenous lines may be placed and crystalloid solutions and/or blood will be administered at rates sufficient to maintain the circulation. Some patients may require a surgical operation called an exploratory laparotomy to repair internal injuries.

[A volume-variable reservoir-pump for a manually operated cardiopulmonary bypass circuit for emergency].

We developed a manually operated portable cardiopulmonary bypass circuit for resuscitation. The circuit is composed of, in turn, a venous drainage catheter, one-way valve, self-inflating reservoir, one-way valve, artificial lung, and an arterial catheter. These components are interlocked with conducting tubes with quick connectors. The priming volume of the circuit is about 300 ml including the self-inflating reservoir of 120 ml in capacity. For a patient with small stature, stroke volume is easily controlled by changing manual compression of the reservoir, but dilution of circulating blood with the priming solution is inevitable. For a controllable reduction of the reservoir volume, we incorporated a thin-walled balloon, which is inflatable from the outside, into the room of the reservoir. If the balloon is inflated with some amount of liquid, the same volume of functional capacity of the reservoir is lost. Thus the reservoir volume is adjusted, the hemodilution with a priming solution is minimized, and an excessive stroke volume with an inadvertent compression of the reservoir-pump is prevented as well. This innovation will make our standard size bypass circuit applicable to almost all patients, except for a newborn or infant who requires a special size of bypass circuit, and improve the survival rate of cardiopulmonary resuscitation.

[Comparison of volume substitutes 5 percent human albumin and 6 percent hydroxyethyl starch (40,000/0.5) in pediatric anesthesia].

Human albumin 5% (HA), frequently used in paediatric anaesthesia as a human plasma substitute, could be replaced by hydroxyethyl starch 6% (HES) 40,000/0.5 provided its use would not entail any disadvantages but rather advantages instead. This problem was studied by examining 30 children (mean body weight 32.5 kg) in general anaesthesia. During about 3 hours of surgery the patients lost up to 15 per cent (approx. 400 ml) of blood volume. In a randomised study the blood loss was compensated either via HA or HES with 14 ml/kg body weight each, respectively. Blood pressure and pulse rate remained within the normal range. Haemodilution was represented by a drop in the erythrocyte count to about 3 million/microliter, haematocrit (HCT) to about 30% and haemoglobin to approx. 10 g/100 ml. Slight metabolic acidosis (Bodansky unit = -4 mmol/l) was found to be statistically not significant (= n.s.) with both methods, as was the difference in serum albumin and during serum electrophoresis. Serum [Na+] was reduced in those children who had been treated with HES, to 137.33 +/- 33.30 mmol/l; however, in those children who received HA with low sodium content (statistically significant difference = s.s.) the corresponding level was 134.15 +/- 2.36 mmol/l. Serum creatinine rose in each case from 60 to 80 mmol/l (s.s.), renal function being slightly impaired probably due to the anaesthesia and surgery. The value according to Quick's test and the partial thromboplastin time (PTT) remained in the normal range both with HA and HES treatment (in each case over 70% and below 25s, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamics

For example, if Hi is 0.30 or less it is not possible to save a red cell mass equivalent to two units of homologous PRBC even if the patient is hemodiluted to an Hm of 0.15. That is because from the RCM equation the patient RCM falls short from the equation giving above. If Hi is 0.40 one must remove at least 7.5 units of blood during ANH, resulting in an Hm of 0.20 to save two units equivalence. Clearly, the greater the Hi and the greater the number of units removed during hemodilution, the more effective ANH is for preventing homologous blood transfusion. The model here is designed to allow doctors to determine where ANH may be beneficial for a patient based on their knowledge of the Hi, the potential for SBL, and an estimate of the Hm. Though the model used a 70 kg patient, the result can be applied to any patient. To apply these result to any body weight, any of the values BLs, BLH and ANHH or PRBC given in the table need to be multiplied by the factor we will call T

Venipuncture

The volume of the blood sample collection is very important in experimental animals. All nonterminal blood collection without replacement of fluids is limited up to 10% of total circulating blood volume in healthy, normal, adult animals on a single occasion and collection may be repeated after three to four weeks. In case repeated blood samples are required at short intervals, a maximum of 0.6 ml/kg/day or 1.0% of an animal's total blood volume can be removed every 24 hours. The estimated blood volume in adult animals is 55 to 70 ml/kg body weight. Care should be taken for older and obese animals. If blood collection volume exceeds more than 10% of total blood volume, fluid replacement may be required. Lactated Ringer's solution (LRS) is recommended as the best fluid replacement by National Institutes of Health (NIH). If the volume of blood collection exceeds more than 30% of the total circulatory blood volume, adequate care should be taken so that the animal does not suffer from

[Not Available].

Bulb suction drains have long been used in various surgical procedures. The purpose of this study was to evaluate 4 commonly used bulb suction devices in vitro to explore the nonlinear changes in draining ability and efficiency along with the conformation changes of the device throughout the draining processes. Under a designed simulated scenario using pure water as the desired draining substance, the relative function of the J-VAC 100 cc (JV100) (Ethicon, Inc, Somerville, USA); the EVACUATOR 125cc (EP125) (Pacific Hospital Supply, Taiwan); the Bulb Reservoir 150 cc (BH150) (Hosmed, Inc, Miami, FL); and the HemoVac 400 cc (HV400) (Zimmer, Inc, Warsaw, IN) drains were compared. The maximum collection capacities and the dead space at maximum compression of each bulb drain were recorded and compared. The collected fluid weight was recorded along with time, and collection speeds were calculated and compared. The maximum collected weight of the 4 drains were 110.07 ± 0.54 g (JV100), 122.7 ± 06.51 g (EP125), 140.8 ± 03.78 g (BH150), and 335.07 ± 04.24 g (HV400). The dead spaces under maximum compression were 15.63 ± 01.32 ml, 19.80 ± 03.37 ml, 34.23 ± 06.77 ml, and 82.83 ± 05.51 ml, respectively. The collecting speed-volume curves were generated from the authors' tested devices. Although slightly different individually, typical characteristics, such as tendency to reach maximum collection speed at the very beginning of the collection phase; rapid decline to about 65% of peak collection speed when approximately 30% of the total collection volume had been achieved; and inefficient collection speed in the later collection phase were noted. Among all the bulb drains tested in this study, all of them performed well in vitro. Although using bulb drains continues to be an effective and economic draining method after operation, clinicians should be aware of the nonlinear features of suction efficiency during the drainage process to avoid unexpected function deterioration. .

Blood pressure measurement

Palpation A minimum systolic value can be roughly estimated by palpation, most often used in emergency situations, but should be used with caution. It has been estimated that, using 50% percentiles, carotid, femoral and radial pulses are present in patients with a systolic blood pressure > 70 mmHg, carotid and femoral pulses alone in patients with systolic blood pressure of > 50 mmHg, and only a carotid pulse in patients with a systolic blood pressure of > 40 mmHg. A more accurate value of systolic blood pressure can be obtained with a sphygmomanometer and palpating the radial pulse. Methods using constitutive models have been proposed to measure blood pressure from radial artery pulse. The diastolic blood pressure cannot be estimated by this method. The American Heart Association recommends that palpation be used to get an estimate before using the auscultatory method. Auscultatory

One thousand dollar assist heart pump for patients from developing countries.

In spite of continuous improvements in device design and applications, the profound use of heart pump has been limited because of its high price. The available clinically applied heart pump costs mostly about 100 thousands US Dollars. The author has since long tried to develop a heart pump costing only 1000 Dollars for recovery or bridge to heart transplantation therapies. The device is a radially driven centrifugal pump with a brush-less DC motor and a streamlined impeller. Its bearing is rolling bearing using 4 to 6 needles, manufactured by special wear-proof polythene with super-high-molecular weight, thus the service life achieves more than 10 years. To avoid thrombus formation, a special purge system is introduced to the bearing, allowing the saline with heparin to be infused through the bearing into the pump. The bearing, therefore, keeps working in the saline, and absolutely no thrombus will be formed along the bearing. Animal experiments demonstrated that a 30 mL fluid infusion per hour is enough to prevent thrombus formation. With these improvements, the impeller pump has continuously run for 14 months in the laboratory, and no bearing wear can be measured. The device, weighing 150 g, is fully implantable, consumes approximately 9.6 W, delivers a 9Lmin-1 blood flow against a 120 mmHg mean pressure, and reaches a highest total efficiency of 24.7% for the motor (including the controller) and the pump. The device has been used in animal experiments together with an American artificial lung for more than one month in the University of Texas and also in human trials in the Taiwan University.

Surgery_Schwartz

response, and eye opening. Scores range from 3 (the lowest) to 15 (normal).Table 7-4Signs and symptoms of advancing stages of hemorrhagic shockCLASS ICLASS IICLASS IIICLASS IVBlood loss (mL)Up to 750750–15001500–2000>2000Blood loss (% BV)Up to 15%15%–30%30%–40%>40%Pulse rate<100>100>120>140Blood pressureNormalNormalDecreasedDecreasedPulse pressure (mmHg)Normal or increasedDecreasedDecreasedDecreasedRespiratory rate14–20>20–3030–40>35Urine output (mL/h)>30>20–305–15NegligibleCNS/mental statusSlightly anxiousMildly anxiousAnxious and confusedConfused and lethargicBV = blood volume; CNS = central nervous system.Brunicardi_Ch07_p0183-p0250.indd 19210/12/18 6:17 PM 193TRAUMACHAPTER 7patients have a progressive increase in circulating blood volume over gestation; therefore, they must lose a relatively larger vol-ume of blood before manifesting signs and symptoms of hypo-volemia (see “Special Populations”).Based on the initial response to fluid resuscitation, hypo-volemic injured

Hemothorax

When a hemothorax occurs, blood enters the pleural cavity. The blood loss from the circulation has several effects. Firstly, as blood builds up within the pleural cavity, it begins to interfere with the normal movement of the lungs, preventing one or both lungs from fully expanding and thereby interfering with the normal transfer of oxygen and carbon dioxide to and from the blood. Secondly, blood that has been lost into the pleural cavity can no longer be circulated. Hemothoraces can lead to significant blood loss – each half of the thorax can hold more than 1500 milliliters of blood, representing more than 25% of an average adult's total blood volume. The body may struggle to cope with this blood loss, and tries to compensate by maintaining blood pressure by forcing the heart to pump harder and faster, and by squeezing or constricting small blood vessels in the arms and legs. These compensatory mechanisms can be recognised by a rapid resting heart rate and cool fingers and toes.