Military Antishock Trousers Research Articles

Guidelines for the Management of a Pregnant Trauma Patient.

Abstract Objective Physical trauma affects 1 in 12 pregnant women and has a major impact on maternal mortality and morbidity and on pregnancy outcome. A multidisciplinary approach is warranted to optimize outcome for both the mother and her fetus. The aim of this document is to provide the obstetric care provider with an evidence-based systematic approach to the pregnant trauma patient. Outcomes Significant health and economic outcomes considered in comparing alternative practices. Evidence Published literature was retrieved through searches of Medline, CINAHL, and The Cochrane Library from October 2007 to September 2013 using appropriate controlled vocabulary (e.g., pregnancy, Cesarean section, hypotension, domestic violence, shock) and key words (e.g., trauma, perimortem Cesarean, Kleihauer-Betke, supine hypotension, electrical shock). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies published in English between January 1968 and September 2013. Searches were updated on a regular basis and incorporated in the guideline to February 2014. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technologyrelated agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. Values The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). Benefits, harms, and costs This guideline is expected to facilitate optimal and uniform care for pregnancies complicated by trauma

Use of pelvic hemostasis belt to control lethal pelvic arterial hemorrhage in a swine model.

Hemorrhage is the leading cause of death for both civilian and battlefield injuries. Hemorrhage from pelvic vascular wounds is of concern since it is difficult to control before surgical intervention. This has resulted in renewed interest in developing presurgical endovascular approaches to hemorrhage control. However, it is likely that other short-term techniques may be needed as a bridge to such approaches. We tested a prototype device called the pelvic hemostasis belt (PHB) for its ability to reduce or halt blood flow in a lethal model of pelvic arterial injury. Seventeen male swine, 42 (5.2)kg were anesthetized, instrumented, and then randomized into three groups (control, military antishock trousers [MAST], and PHB). Animals underwent laparotomy with placement of a 4-0 stainless steel monofilament suture through the right iliac artery. The laparotomy was closed, and the iliac suture was exteriorized. Hemorrhage was produced by pulling the suture through the iliac artery. In both PHB and MAST groups, the devices were applied over the pelvis and lower abdomen for 60 minutes, followed by release and monitoring for 30 minutes or until the animal expired. Hetastarch (500 mL) was infused immediately after commencement of hemorrhage. All PHB group animals and only two from the MAST group survived for 60 minutes. Mean (SD) survival time for the control group was 13 (12.3) minutes. Log-rank (Mantel-Cox) survival analysis demonstrated a significant difference in survival time when comparing all groups (p < 0.0001) as well as when comparing PHB and MAST groups (p = 0.018). Significant differences were noted between groups in mean arterial pressure, lactate, and central venous hemoglobin oxygen saturation levels. The PHB was successful in improving survival for 60 minutes after a lethal vascular injury. Such a device may be helpful to bridge endovascular methods of hemorrhage control.

Abstract 177: Testing of a Novel Pelvic Hemostasis Belt to Control Lethal Pelvic Arterial Hemorrhage

Objectives: Hemorrhage is the leading cause of death for both battlefield and injuries civilian. Hemorrhage caused by pelvic vascular injuries is of particular concern since it is challenging to manage or control prior to surgical intervention. Recently, there has been renewed interest in developing pre-surgical endovascular interventions to control such hemorrhage. However, other short-term techniques may be needed as a conduit to such endovascular approaches. Attempts at external tamponade of these complex injuries as a bridge to definitive surgical care of such injuries is not new. We tested a prototype device called the Pelvic Hemostasis Belt (PHB) for its ability to reduce or stop blood flow in a lethal model of pelvic arterial injury. Methods: Twelve male swine, 43(5.6) kg were utilized in this study. Animals were anesthetized, instrumented then randomized into two groups, Military Anti Shock Trousers group (MAST) and Pelvic Hemostasis Belt group (PHB). Through laparotomy, a stainless-steel monofilament suture was placed through the right iliac artery, the abdomen was closed and the suture was exteriorized. Hemorrhage was produced by pulling the suture through the iliac artery. In both groups, the hemostasis devices (MAST or BHP) were applied over the pelvis and lower abdomen for 60 minutes followed by release and monitoring for 30 minutes or until the animal expired. An infusion of 500 mL of hetastarch was started immediately after initiation of hemorrhage. Results: All animals in the PHB group and only two from the MAST group survived for 60 minutes. Average survival time for the rest of the MAST group was 44(17.9) minutes. The log-rank (Mantel-Cox) survival analysis demonstrated a significant difference in survival time between PHB and MAST group (p = 0.018). Significant differences were noted between the two groups in mean arterial pressure, lactate and central venous hemoglobin oxygen saturation levels. Conclusion: The PHB was successful in improving survival for 60 minutes after a lethal vascular injury. The Pelvic Hemostasis Belt might be helpful to bridge endovascular methods of hemorrhage control.

Viewpoint

Viewpoint

Medical reversal: What are you doing wrong for your patient today?

Medical reversal: What are you doing wrong for your patient today?

Understanding Commonly Encountered Limitations in Clinical Research: An Emergency Medicine Resident's Perspective

The breadth of emergency medicine and the rapid growth in relevant research makes an ability to assess new research findings particularly important for emergency physicians. Improvements in the treatment of acute myocardial infarction, evolution of thrombolytic use in acute stroke, and the demise of military antishock trousers for traumatic shock provide examples of the dynamic relationship between emergency medicine research and clinical practice. The purpose of this article is to provide an overview of common research limitations and flaws relevant to emergency medicine. We explain and provide published examples of problems related to external validity, experimenter bias, publication bias, straw man comparisons, incorporation bias, randomization, composite outcomes, clinical importance versus statistical significance, and disease-oriented versus patient-oriented outcomes. For residents, familiarity with these concepts will allow for better interpretation of evidence-based lectures and improved understanding and participation during journal clubs. For those who learn best from review articles, textbooks, or other summaries of primary literature, awareness of these issues is needed to understand critiques raised by reviewers. For all readers, knowledge of these commonly encountered methodological problems will improve the emergency provider’s ability to determine whether and how new scientific developments serve to inform clinical practice. By necessity, this article is only a starting point for learning about these subjects, many of which are complex. Readers are encouraged to refer to questions and answers from the Annals of Emergency Medicine Journal Club series. Available topics from this series are described in Appendix E1, available online at http://www.annemergmed.com.

Posterior Thigh Compartment Syndrome as a Result of a Basketball Injury

Acute compartment syndrome of the thigh is a serious although rare occurrence that was sparsely documented in the orthopedic literature until Schwartz et al reported on a series of 21 cases. Although classically associated with high-energy femur fracture, thigh contusion, or the use of military anti-shock trousers, compartment syndrome of the thigh has recently been diagnosed in seemingly low-energy injuries. A complete hamstring avulsion from its ischial origin during routine ambulation and rupture of the quadriceps tendon after a low-energy fall have been shown to result in compartment syndrome. In light of the potential medicolegal ramifications surrounding the diagnosis of compartment syndrome, emergency room consultations to rule out compartment syndrome are on the rise. Specifically, the time to fasciotomy was found to be linearly related to indemnity payment, and a fasciotomy performed within 8 hours was uniformly associated with a successful defense. This article describes a case of a 29-year-old healthy man who developed posterior thigh compartment syndrome as a result of an intrasubstance tear of the biceps femoris muscle sustained while attempting a lay-up during a recreational basketball game. His posterior thigh compartment pressure measured 70 mm Hg and he required emergent posterior thigh compartment fasciotomy.

Management of Hemorrhage in Life-threatening Pelvic Fracture

Emergent life-saving treatment is required for high-energy pelvic fracture with associated hemorrhage and hemodynamic instability. Advances in prehospital, interventional, surgical, and critical care have led to increased survival rates. Pelvic binders have largely replaced military antishock trousers. The availability and precision of interventional angiography have expanded considerably. External pelvic fixation can be rapidly applied, often reduces the pelvic volume, and provides temporary fracture stabilization. Pelvic packing, popularized in Europe, is now used in certain centers in North America. The use of standardized treatment algorithms may improve decision making and patient survival rates. Active involvement of an experienced orthopaedic surgeon in the evaluation and care of these critically injured patients is essential.

Military anti-shock garment: Historical relic or a device with unrealized potential?

Military anti-shock trousers represents a medical device which has engendered very divergent views, even up to today. From the time the concept was formulated in 1903 by surgeon George W Crile, there have been significant swings in opinion and evidence. The guidelines, where available, are often kept relatively general and cautious. As a spin-off to the mechanism and technology, several alternative devices have been proposed or developed over the years. This include the auto-transfusion torniquet, the non pneumatic anti-shock garment (Life Wrap) and the non inflatable antishock garment, which are discussed in this paper.

Vascular Air Embolism: Lung Injury and Its Pathophysiology Also Need to Be Considered

Vascular Air Embolism: Lung Injury and Its Pathophysiology Also Need to Be Considered

The Circumferential Antishock Sheet

Hemorrhage control in patients with pelvic ring disruptions remains problematic. To decrease bleeding, efforts have been made to acutely reduce and stabilize the pelvis. The goals of rapid pelvic reduction and stabilization are restoration of normal pelvic volume, protection of the early clot, and improved patient comfort. The use of military antishock trousers, hip spica casts, external fixators, antishock pelvic clamps, early open reduction/internal fixation, and open packing have been reported in the literature. A simple temporary technique of reduction is reported using a circumferential bed sheet. The sheet is placed between the iliac crests and the greater trochanters, encircling the pelvis. The circumferential sheet provides stabilization for transportation and allows transfemoral angiographic embolization or exploratory laparotomy at the receiving hospital. Definitive fixation can then be accomplished.

Role of Impaired Lower-Limb Venous Innervation in the Pathogenesis of the Chronic Fatigue Syndrome

In patients with acute orthostatic hypotension, there is excessive pooling of blood in the legs, which may result from the strikingly subnormal compliance that is demonstrable in the pedal veins during norepinephrine infusion. The common occurrence of delayed orthostatic hypotension and/or tachycardia in the chronic fatigue syndrome (CFS) led to the present studies of foot vein compliance in CFS patients with a linear variable differential transformer. Seven patients with CFS were compared with 7 age- and gender matched healthy control subjects in their blood pressure, heart-rate, and plasma norepinephrine responses to prolonged standing and in measurements of their foot vein contractile responses to intravenous norepinephrine infusions with the linear variable differential transformer. Excessive, delayed (usually after 10 min) orthostatic reductions in systolic and diastolic blood pressure (P < 0.01) and inconsistently excessive increases in heart rate were found in the CFS patients, in whom venous compliance in response to infused norepinephrine was significantly reduced (P < 0.05). In these patients with CFS, delayed orthostatic hypotension was clearly demonstrable, and, as in previously reported patients with orthostatic hypotension of acute onset, this was associated with reduced pedal vein compliance during norepinephrine infusion, implying impaired sympathetic innervation of foot veins. The rapid symptomatic improvement demonstrated in previous studies of CFS patients during correction of orthostatic venous pooling by inflation of military antishock trousers (MAST) to 35 mm Hg may suggest that excessive lower body venous pooling, perhaps by reducing cerebral perfusion, is involved in the orthostatic component of fatigue in these patients.

The roles of orthostatic hypotension, orthostatic tachycardia, and subnormal erythrocyte volume in the pathogenesis of the chronic fatigue syndrome.

Orthostatic hypotension during upright tilt is an important physical disorder in patients with chronic fatigue syndrome. We have tested its occurrence during prolonged standing, whether it is correctable, and whether reduced circulating erythrocyte volume is present. Fifteen patients were randomly selected from a large population of patients with chronic fatigue syndrome, studied, and observed for several years (by DSB). Blood pressure (BP) and heart rate (HR) measured with Dinamap every minute for 30 minutes supine and 60 minutes standing were compared with these findings in 15 healthy age- and gender-matched control subjects and later during lower body compression with military antishock trousers (MAST). Plasma catecholamines and circulating erythrocyte and plasma volumes were also measured by isotopic dilution methods. Abnormal findings in the patients included excessive orthostatic reductions in systolic (P < 0.001) and diastolic BP (P < 0.001) and excessive orthostatic tachycardia (P < 0.01), together with presyncopal symptoms in 11 of the 15 patients and in none of the control subjects after standing for 60 min. Lower body compression with the MAST restored all orthostatic measurements to normal and overcame presyncopal symptoms within 10 min. Circulating erythrocyte but not plasma volumes were subnormal in the 12 women (P < 0.01) and plasma norepinephrine concentration rose excessively after standing for 10 min. Delayed orthostatic hypotension and/or tachycardia caused by excessive gravitational venous pooling, which is correctable with external lower-body compression, together with subnormal circulating erythrocyte volume, are very frequent, although not invariably demonstrable, findings in moderate to severe chronic fatigue syndrome. When present, they may be involved in its pathogenesis.

Pulmonary air embolism.

Pulmonary air embolism is a well-known consequence of surgery, trauma, diving, and aviation. This article reviews the physiological effects, means of detection and methods of prevention and treatment of pulmonary air embolism. The primary physiological effects are elevated pulmonary artery pressures, increased ventilation-perfusion inhomogeneity, and right ventricular failure. The degree of physiological impairment depends on the volume of gas entrained, the rate of entrainment, the type of gas entrained, and the position of the patient when the embolism occurs. Transesophageal echocardiography is the most sensitive method of detection, but it is invasive. Precordial Doppler ultrasound is almost as sensitive and poses no risk to the patient. End-tidal carbon dioxide monitoring is used on all patients and is a moderately sensitive method of detection, which is useful during surgeries that have a low incidence of air embolism. For high-risk procedures, precordial Doppler ultrasound and a multi-orifice right heart catheter should be used to detect and treat pulmonary air embolism. Prevention measures include volume expansion, careful positioning, positive end-expiratory pressure, military anti-shock trousers, and jugular venous compression. Treatment of pulmonary air embolism includes flooding the surgical site with saline, controlling sites of air entry, repositioning the patient with the surgical site below the right atrium, aspiration of air from a central venous catheter, cessation of inhaled nitrous oxide, and resuscitation with oxygen, intravenous fluids, and inotropic agents. Some hypotheses on the effects of air in the pulmonary vasculature and investigational treatment options are discussed.

Civilian Versus Military Trauma Dogma: Who Do You Trust?

Combat trauma differs from its peacetime counterpart by involving a different spectrum of injuries, occurring in austere environments, dealing with mass casualties, and embodying inherent treatment delays. Thus, civilian trauma practices may be inappropriate in certain combat settings. A review of historical as well as current vivilian and military data is presented for four trauma topics (military antishock trousers, wound debridement, colon wounds, fluid resuscitation) in which civilian and military principles have clashed. The following recommendations are made. (1) Military antishock trousers are still useful in a combat setting. (2) Soft-tissue wound management should be directed by the wound rather than by the weapon. (3) Cautious avoidance of colostomy may be indicated in certain wartime colon wounds. (4) The majority of combat casualties require early vigorous fluid resuscitation. When civilian trauma experience challenges military dogma, it must be carefully considered before being applied to a combat setting.

A New Approach to Teaching Prehospital Trauma Care to Paramedic Students

Study objective: A modification of the standard Department of Transportation student paramedic curriculum encouraging individualized patient assessment decreases inappropriate on-scene procedures (OSPs) and scene time, measured on simulated patients. Methods: Scenario-based testing from 1991 through 1993 was videotaped for all students. A new trauma curriculum was introduced in 1992, individualizing patient assessment and prioritization of OSPs. Recorded OSPs included spinal immobilization, application of military antishock trousers, endotracheal intubation, cricothyrotomy, intravenous catheter insertion, and needle thoracostomy. Twenty videotaped random student performances of the 1991 class was compared with a similar sample of 20 from the 1993 class; scene times and the OSP numbers were measured. Two board-certified independent emergency physicians unfamiliar with the students or the new curriculum reviewed all 40 tests on a master videotape. Patient assessment appropriateness, scene time, OSPs, scenario difficulty, and number of inappropriate OSPs were evaluated using a linear analog scale. Data are presented as means with confidence intervals (CIs), analyzed by Student’s t test and the Mann-Whitney 2-sample test. Results: Scene time from 1991 to 1993 decreased overall with a mean of 4.3 minutes (95% CI 2.8 to 5.8 minutes), as did the number of OSPs: 3.1 versus 1.7 (mean difference, 1.45 OSPs per scenario; 95% CI .91 to 1.99). Physician reviewers noted improvements in the appropriateness of patient assessment, scene time, and OSPs from 1991 to 1993. There was no significant difference in scenario difficulty for 1991 compared with 1993. Inappropriate OSPs done on scene declined. Physician 1 indicated a mean of inappropriate procedures of 1.6 in 1991 versus .5 in 1993. Physician 2 indicated a mean of 1.4 in 1991 versus .3 in 1993. Conclusion: This new paramedic curriculum decreased on-scene time and inappropriate use of procedures in stabilizing the condition of patients with simulated critical trauma. [Johnson DR, Macias D, Dunlap A, Hauswald M, Doezema D: A new approach to teaching prehospital trauma care to paramedic students. Ann Emerg Med January 1998;33:51-55.]

Prehospital interventions in children

Objectives. Frequently performing procedures assists in skill maintenance. This study was conducted to characterize the frequency and types of basic and advanced prehospital interventions performed on children. Methods. A retrospective study was conducted over a three-month period from emergency medical services (EMS) units working in central Michigan. Data were collected for age, sex, at-scene time, total run time, basic procedures (e.g., spinal immobilization), and advanced procedures (e.g., venous access). Results. A total of 535 EMS runs were reviewed. Runs were excluded for transport refusal (105) and site-to-site transfer (6). Of the remaining 424 children, 287 received an intervention (group 1) and 137 did not (group 2). Group 1 (9.5 ± 5.6 years) was older (p <0.001) than group 2 (6.0 ± 5.8 years). There was no gender predominance between group 1 and group 2 (p = 0.06). In group 1 there were 104 patients who received multiple procedures. Basic procedures (n = 328) included spinal immobilization (149), oxygen administration (123), splinting (27), wound care (24), use of military anti-shock trousers (4), and cardiopulmonary resuscitation (1). Advanced procedures (n = 112) included venous access (65), medications of all routes (26), and cardiacoximetry monitoring (21). No child had an intraosseous line started and no child was successfully intubated. Only 82 of the 424 children (19.3%) had an advanced procedure. Group 1 at-scene times (16.1 ± 8.1 min) were longer (p <0.001) than those of group 2 (11.1 ± 6.6 min). Total run times for group 1 (35.7 ± 15.5 min) were longer (p <0.001) than those for group 2 (26.7 ±11.3 min). Conclusions. Advanced EMS procedures were performed on only 19.3% of children. Opportunities to perform critical interventions (e.g., intubation) were rarely present. Children receiving procedures were older and had longer scene and run times.

Right Ventricular Function in Human Sepsis: A Thermodilution Study

To assess the relations among right ventricular (RV) pressures and volumes in sepsis. Prospective study. ICU. Eighteen patients with sepsis who were in hemodynamically stable condition. Stepwise increases and decreases in RV end-diastolic volume (EDV) as induced by military antishock trousers (MAST) inflation of 0, 15, 30, 50 and then 0 mm Hg over 15-min intervals. RV volumes and pressures were measured using a rapid response thermistor pulmonary arterial catheter based on RV ejection fraction (RVEF) calculations. RV EDV was estimated as stroke volume (SV)/RVEF, while RV end-systolic volume (ESV) was estimated as EDV-SV. Right atrial pressure (Pra) was taken as end-diastolic pressure, and pulmonary artery pressures (Ppa), both mean and end-systolic, were used as RV ejection pressures. MAST inflation to 15 mm Hg had no measurable effects on the measured variables. However, inflation to 30 and 50 mm Hg increased Pra, both mean and end-systolic Ppa, EDV, and ESV, whereas SV and RVEF remained unchanged. The relation between either Pra and EDV (r=0.33) or the change in Pra and EDV, mean or end-systolic Ppa and ESV (r=0.5 and 0.28, respectively), or the change in mean or end-systolic Ppa and ESV for both the group and individual subjects was poor. Furthermore, SV correlated poorly with EDV (r=0.32), while RVEF correlated better with both EDV and ESV (r=-0.41 and -0.69, respectively), although it showed no definable relation to mean or end-systolic Ppa. However, both absolute and relative changes in EDV corresponded closely with respective ESV values (r=0.93). During sepsis, RV EDV and ESV vary independently of changes in Pra and ejection pressure. These data can be explained by assuming that the RV is a highly compliant chamber during filling, such that changes in RV EDV do not alter RV wall stress (preload) or ejection efficiency (RVEF). Thus, changes in RV EDV should proportionally alter RV ESV. Furthermore, the slope of the ESV/EDV relation should be inversely proportional to ejection efficiency.

CONTROVERSIES IN SHOCK RESEARCH: HYPERTONIC RESUSCITATION—PROS AND CONS

The proper fluid resuscitation of hemorrhagic shock is still controversial. Hypertonic saline has been suggested for prehospital resuscitation of hemorrhagic shock, because of its superior ability to expand blood volume and elevate systemic blood pressure and cardiac output in a small volume and during a short time period. We have defined two types of hemorrhagic shock: controlled hemorrhagic shock (CHS), where the bleeding source is immediately occluded following hemorrhage, and uncontrolled hemorrhagic shock (UCHS), where bleeding is induced by injury to blood vessels that are left unoccluded. It was observed that hypertonic saline (HTS) treatment of controlled hemorrhagic shock leads to an increase in blood pressure and cardiac output, while HTS treatment of UCHS leads to increased bleeding from injured blood vessels, hemodynamic deterioration, and increased mortality. Conversion of UCHS to CHS by tourniquet, military antishock trousers, or surgical hemostasis prevented excessive bleeding and mortality following HTS. Several clinical studies have used hypertonic saline dextran (HSD) or hypertonic saline (HS) for treatment of trauma casualties, but to date no significant improvement in mortality has been demonstrated by either HS or HSD. A more favorable effect but still not statistically significant effect has been demonstrated in patients with a Glasgow Coma Scale of 8 or less. The efficacy of HS has not clearly been established in clinical trials, in all of which HS was used in combination with conventional crystalloid therapy. Further human trials are required to better define the patient population that would benefit most from the prehospital administration of HS.

Hypertonic saline infusion in hemorrhagic shock treated by military antishock trousers (MAST) in awake sheep

To determine the effect of military antishock trousers (MAST) combined with hypertonic saline in controlled hemorrhagic shock in an awake sheep model. Prospective, randomized, controlled study. University research laboratory. Healthy adult sheep (21 to 33.5 kg) were studied in four experimental groups. Sheep underwent cannulation of the jugular vein and the carotid artery. An indwelling catheter was also inserted into their bladders. Mean arterial, pulmonary arterial, pulmonary artery occlusion, and central venous pressures, cardiac and stroke volume indices, systemic and pulmonary vascular resistances, PaO2 and PaCO2, and serum lactate and hemoglobin concentrations were measured at baseline, after induction of hemorrhagic shock, and subsequently during resuscitative treatments of normal saline, MAST, hypertonic saline, and the combination of MAST and hypertonic saline. Controlled hemorrhagic shock was induced by arterial bleeding of 40 mL/kg in all animals. The sheep were randomized into four groups. In group 1 (n = 5), controlled hemorrhagic shock was treated by 5 mL/kg sodium chloride 0.9% (isotonic saline). In group 2 (n = 6), controlled hemorrhagic shock was treated by 5 mL/kg sodium chloride 7.5% (hypertonic saline). In group 3 (n = 5), controlled hemorrhagic shock was treated by MAST inflated to 40 mm Hg followed by 5 mL/kg sodium chloride 0.9%. In group 4, controlled hemorrhagic shock was treated by MAST (40 mm Hg) followed by 5 mL/kg of hypertonic saline. Arterial bleeding was followed by significant decreases in mean arterial pressure (87 +/- 1 to 41 +/- 4 mm Hg; p < .001), cardiac index (4.6 +/- 0.4 to 2.0 +/- 0.2 L/min/m2; p < .001), and urine output (102 +/- 30 to 13.0 +/- 7 mL/hr; p < .001), and an increase in systemic vascular resistance (1517 +/- 130 to 2601 +/- 370 dyne.sec/cm5; p < .001). MAST inflation in group 3 increased systemic vascular resistance to 3018 +/- 399 dyne.sec/cm5 (p < .05) and mean arterial pressure to 79 +/- 5 mm Hg (p < .05), while cardiac index, urine output, and lactate concentration remained unchanged. Infusion of hypertonic saline after MAST inflation (group 4) resulted in an increase in mean arterial pressure to 99 +/- 4 mm Hg (p < .001), an increase in cardiac index to 4.1 +/- 0.4 L/min/m2 (p < .001), an increase in urine output to 221 +/- 93 mL/hr (p < .001), and a decrease in systemic vascular resistance to 1847 +/- 175 dyne.sec/cm5 (p < .005). In hemorrhagic shock, the combination of MAST and hypertonic saline increases mean arterial pressure, improves cardiac output and tissue perfusion during the application of MAST, and also prolongs for > 2 hrs the short beneficial effect of hypertonic saline on mean arterial pressure.