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Biomedical subjects

M Rocha e Silva

Publications and source records attributed to M Rocha e Silva.

At least 19 recordsLinked to original sources
PubMed2006

Systemic and regional hemodynamic effects of enalaprilat infusion in experimental normotensive sepsis.

Angiotensin-converting enzyme inhibitors have been shown to improve splanchnic perfusion in distinct shock states. We hypothesized that enalaprilat potentiates the benefits of early fluid resuscitation in severe experimental sepsis, particularly in the splanchnic region. Anesthetized and mechanically ventilated mongrel dogs received an intravenous infusion of live Escherichia coli over a period of 30 min. Thereafter, two interventions were performed: fluid infusion (normal saline, 32 mL/kg over 30 min) and enalaprilat infusion (0.02 mg kg(-1) min(-1) for 60 min) in randomized groups. The following groups were studied: controls (fluid infusion, N = 4), E1 (enalaprilat infusion followed by fluid infusion, N = 5) and E2 (fluid infusion followed by enalaprilat infusion, N = 5). All animals were observed for a 120 min after bacterial infusion. Mean arterial pressure, cardiac output (CO), portal vein blood flow (PVBF), systemic and regional oxygen-derived variables, and lactate levels were measured. Rapid and progressive reductions in CO and PVBF were induced by the infusion of live bacteria, while minor changes were observed in mean arterial pressure. Systemic and regional territories showed a significant increase in oxygen extraction and lactate levels. Widening venous-arterial and portal-arterial pCO2 gradients were also detected. Fluid replacement promoted transient benefits in CO and PVBF. Enalaprilat after fluid resuscitation did not affect systemic or regional hemodynamic variables. We conclude that in this model of normotensive sepsis inhibition of angiotensin-converting enzyme did not interfere with the course of systemic or regional hemodynamic and oxygen-derived variables.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2005

Active spleno-femoral shunt avoids splanchnic congestion during portal triad occlusion: an experimental study.

UNLABELLED: Portal triad occlusion (PTO) is often performed during hepatic resections for trauma or malignancies to minimize intraoperative blood loss. The pringle maneuver is also regularly required during liver transplantation. This maneuver leads to temporary hepatic ischemia and may be associated with splanchnic blood flow congestion, promoting undesirable hemodynamic disturbances in some patients. Veno-venous bypass is a useful, easily performed technique that may avoid those deleterious hemodynamic effects of PTO. We tested the hypothesis that an active spleno-femoral shunt maintains hemodynamic stability and promotes complete decompression of the mesenteric bed, avoiding intestinal mucosal blood congestion, during PTO. METHODS: Seven dogs (17.2 +/- 0.9 kg) were subjected to 45 minutes of hepatic ischemia during which there was an active spleno-femoral shunt. Systemic hemodynamics were evaluated through Swan-Ganz and arterial catheters. Splanchnic perfusion was assessed by portal vein blood flow and hepatic artery blood flow (PVBF and HABF, ultrasonic flowprobe), intestinal mucosal-arterial pCO(2) gradient (D(t-a)pCO(2), tonometry), and regional O(2)-derived variables. RESULTS: No significant changes in systemic and regional parameters were observed during the ischemia period. During reperfusion, a significant decrease in mean arterial pressure, PVBF, and arterial pH was observed. A significant increase in ALT and D(t-a)pCO(2) (4.8 +/- 2.5 to 18.9 +/- 3 mm Hg) was also observed following hepatic blood flow restoration. CONCLUSION: Spleno-femoral shunt maintains systemic hemodynamic stability, with an effective decompression of the splanchnic bed during portal triad occlusion. The deleterious hemodynamic and metabolic effects observed during reperfusion period, such as transitory hypotension, high D(t-a)pCO(2), and acidemia, were associated with an isolated hepatic ischemia-reperfusion injury, not with the blood congestion in the splanchnic bed.

Animals↗
PubMed2005

Hepatic arterial buffer response fails to restore hepatic oxygenation after temporary liver dearterialization in canines.

BACKGROUND: Hepatic artery thrombosis is a rare but extremely troublesome condition after liver transplantation. Recently, urgent arterial revascularization has been used as rescue therapy, leading to improved graft and patient survivals. Hepatic artery ligation produces a progressive reduction in portal vein blood flow. Theoretically, a hyperemic response may be expected following hepatic artery reperfusion (hepatic artery buffer response, HABR). In this study, we tested the hypothesis that HABR can maintain adequate liver oxygenation after temporary liver dearterialization. METHODS: Seven dogs (19.7 +/- 1.2 kg) subjected to 60 minutes of hepatic artery occlusion were observed for 120 minutes thereafter. Systemic hemodynamics was evaluated through Swan-Ganz and arterial catheters, and splanchnic perfusion by portal vein and hepatic artery blood flows (PVBF and HABF) via an ultrasonic flowprobe. Liver enzymes (ALT and LDH) and systemic and hepatic oxygen delivery (DO2hepat) were calculated using standard formulae. RESULTS: Hepatic artery occlusion induced a progressive reduction in PVBF and DO2hepat. A complete restoration of HABF after hepatic artery declamping was observed; however, the DO2hepat (33.3 +/- 5.9 to 16.5 +/- 5.9 mL/min) did not return to the baseline levels. CONCLUSION: Temporary hepatic artery occlusion induced a progressive decrease in portal vein blood flow during ischemia, an effect that continued during the reperfusion period. The hepatic artery blood flow was promptly restored after declamping. However, HABR was not able to restore hepatic oxygen delivery to baseline levels during the reperfusion period.

Animals↗
PubMed2003

Effects of hypertonic sodium chloride solution on the electrophysiologic alterations caused by bupivacaine in the dog heart.

The effects of various hypertonic solutions on the intraventricular conduction, ventricular repolarization and the arrhythmias caused by the intravenous (iv) injection of bupivacaine (6.5 mg/kg) were studied in sodium pentobarbital-anesthetized mongrel dogs. Hypertonic solutions, given iv 5 min before bupivacaine, were 7.5% (w/v) NaCl, 5.4% (w/v) LiCl, 50% (w/v) glucose (2,400 mOsm/l, 5 ml/kg), or 20% (w/v) mannitol (1,200 mOsm/l, 10 ml/kg). Bupivacaine induced severe arrhythmias and ventricular conduction and repolarization disturbances, as reflected by significant increases in QRS complex duration, HV interval, IV interval and monophasic action potential duration, as well as severe hemodynamic impairment. Significant prevention against ventricular electrophysiologic and hemodynamic disturbances and ventricular arrhythmias was observed with 7.5% NaCl (percent increase in QRS complex duration: 164.4 +/- 21.8% in the non-pretreated group vs 74.7 +/- 14.1% in the pretreated group, P<0.05; percent increase in HV interval: 131.4 +/- 16.1% in the non-pretreated group vs 58.2 +/- 7.5% in the pretreated group, P<0.05; percent increase in monophasic action potential duration: 22.7 +/- 6.8% in the non-pretreated group vs 9.8 6.3% in the pretreated group, P<0.05; percent decrease in cardiac index: -46 6% in the non-pretreated group vs -28 +/- 5% in the pretreated group, P<0.05). The other three hypertonic solutions were ineffective. These findings suggest an involvement of sodium ions in the mechanism of hypertonic protection.

Anesthetics, Local↗
PubMed2001

Radioisotope blood volume measurement in uncontrolled retroperitoneal haemorrhage induced by a transfemoral iliac artery puncture.

Standard-of-care, large volume crystalloid infusion, in the setting of uncontrolled bleeding, has been challenged and it is not known if fluid resuscitation increases retroperitoneal hemorrhage. We developed an experimental model of retroperitoneal haemorrhage to correlate haemodynamic and metabolic alterations with the blood volume loss. Anaesthetised, spontaneously breathing dogs (17.1+/-0.56 kg) were randomised to unilateral (UL, n=11) or bilateral (BL, n=11) iliac artery puncture, using a metallic device introduced through the femoral arteries and followed for 120 min. Initial and final blood volumes were determined using radioactive tracers, 99mTC and 51Cr, respectively. UL was associated with a stable arterial pressure and a moderate decrease in cardiac output and oxygen delivery. BL induced an abrupt and sustained decrease in mean arterial pressure, from 131.9+/-5.9 to 88.6+/-10.8 mmHg, and a much greater reduction in cardiac output, oxygen delivery and consumption than UL throughout the experiment. Total retroperitoneal blood loss after BL was 36.8+/-3.2 ml/kg, while after UL was 25.1+/-3.4 ml/kg (P=0.0262). We conclude that a transfemoral bilateral iliac artery puncture produces a clinically relevant model of uncontrolled retroperitoneal haemorrhage, with hypotension and low flow state, while a unilateral iliac artery lesion causes a compensated shock state.

Animals↗
PubMed2001

Increases in fines and driver licence withdrawal have effectively reduced immediate deaths from trauma on Brazilian roads: first-year report on the new traffic code.

Road accidents are a major cause of death in Brazil, with rates increasing steadily for years. Our objective here is to report the impact of the new Brazilian Traffic Code, introduced in 1998. Its main new features include a large increase in fines and a rigid penalty scoring system that leads to driver license withdrawal. Speed limits have actually been raised on many roads, but adherence to the rules has been monitored more closely. We compare the incidence of injured patients and immediate deaths in road accidents and emergency room admissions to a level I trauma centre in downtown São Paulo between January and December 1998 with corresponding data from between January and December 1997. There was an overall 21.3% reduction in the number of accidents and a 24.7% reduction in immediate deaths, saving 5962 lives on Brazilian highways. Tickets issued fell by 49.5% (601977 during 1997 to 304785 during 1998). Motor vehicle accident-related emergency room admissions decreased by 33.2%. We conclude that very costly tickets and threatened driver licences have proved very effective in decreasing immediate deaths from trauma. Further advances in educational programmes associated with road and vehicle safety measures are likely to provide the much needed further reduction in the still high trauma mortality on Brazilian roads and streets.

Accidents, Traffic↗
PubMed2000

Myocardial reperfusion: leukocyte accumulation in the ischemic and remote non-ischemic regions.

Neutrophil accumulation in the first hour of myocardial reperfusion was assessed in dog hearts submitted to ischemia with and without necrosis. In anesthetized dogs, the left anterior descending coronary artery was occluded for 20 min (group IS-20 n = 7) and for 90 min (group IS-90 n = 6). Immediately after reperfusion, 99m Tc-Ceretec (Exametazime-Amersham) labeled neutrophils were injected into a central vein and 60 min later the dogs were killed. The left ventricle was isolated, weighed, and sliced. Six sections, 3 from normal and 3 from reperfused regions, were divided into endocardial and epicardial layers. Myocardial and blood radiometry were used to evaluate the neutrophil accumulation during reperfusion. The differences between leukocyte accumulation in both groups were assessed comparing the ischemic/normal relations in the endocardial and epicardial layers. A second comparison considered myocardium/blood relations to allow the evaluation of differences between remote normal myocardial areas of the two experimental groups. In dogs submitted to 20 min of ischemia, leukocytes accumulated significantly more (P < 0.01) in the reperfused myocardium as compared with the non-ischemic region. The increase occurred both in the endocardial (1.49+/-0.20) and epicardial (1.48+/-0.29) regions. After 90 min ischemia, leukocyte accumulation was more intense and predominant in endocardium where there was a 4-fold (3.97+/-1.28) increase over the non-ischemic region, while in the epicardium this relation was only 2.5-fold (2.56+/-0.98). In the remote non-ischemic myocardium, leukocyte accumulation was greater in dogs submitted to 90 min of ischemia compared to the 20 min group (P < 0.01), without distinction between endocardial and epicardial layers. This accumulation in territories of non-culprit coronary arteries may be related to the blood flow abnormalities and matrix structure changes that occur in these regions during the development of an acute myocardial infarction and its natural repair.

Animals↗
PubMed2000

Hypertonic saline and pentoxifylline prevent lung injury and bacterial translocation after hemorrhagic shock.

Previous reports have shown beneficial effects of pentoxifylline (PTX) and hypertonic saline (HS) in the treatment of hemorrhagic shock. We compared the effects of these solutions to those of conventional lactated Ringer's (LR) treatment on bacterial translocation (BT), lung injury and total and differential cell count in the bronchoalveolar lavage fluid (BAL) after hemorrhagic shock. Rats (280-330 g) were bled to a MAP of 35 mmHg for 1 h and then randomized into 4 groups: LR (3x shed blood); HS (7,5% NaCl, 4 mL/kg); LR+PTX (25 mg/kg) and SHAM (no shock, no treatment). Additionally, total shed blood was reinfused. At 24 h lung injury was analyzed by a pathologist blinded to the groups, and a score was calculated. BT was determined by microbiological cultures of mesenteric lymph node complex. BAL was performed on a separate set of animals that received the same treatments. Lung score was significantly higher in LR group (11.5+/-1.4) as compared to HS (6.8+/-0.9), and PTX treated animals (7.2+/-0.9). The percentage of neutrophils in the BAL of LR animals (15.8%) was also significantly higher as compared with HS (5.25%) and PTX groups (9.72%). BT was noted in 50% of rats for LR group, 30% for PTX, 10% for HS and 0% for sham group. HS and PTX reduced BT and lung injury after hemorrhage. Attenuation of lung injury could be the result of less neutrophil infiltration into the lungs of HS and PTX treated animals. LR resuscitation caused pronounced lung injury and BT.

Animals↗
PubMed1999

Thermal filament continuous thermodilution cardiac output delayed response limits its value during acute hemodynamic instability.

BACKGROUND: It has been suggested that measurement of continuous cardiac output (CCO) is an advancement in the management of critically ill patients. Our objective was to determine the accuracy of CCO during the rapid hemodynamic changes induced by hemorrhage and resuscitation. METHODS: In 12 anesthetized dogs (20.2+/-0.9 kg), pulmonary artery blood flow, our "gold standard" cardiac output, was measured with an sonographic flowprobe, whereas CCO, intermittent bolus cardiac output (ICO), and mixed venous oxygen saturation were measured with a thermodilution fiberoptic pulmonary artery catheter with a thermal filament. A graded hemorrhage (20 mL/min) was produced to a mean arterial pressure of 40 mm Hg, which was maintained at this level for 30 minutes. Total shed blood volume (701+/-53 mL) was retransfused at a rate of 40 mL/min, over 30 minutes, after which a massive hemorrhage (100 mL/min) was produced over 10 minutes. RESULTS: Hemorrhage induced significant decreases in mean arterial pressure, mixed venous oxygen saturation, and oxygen delivery, which were all restored during early resuscitation. However, CCO showed a delayed response after hemorrhage and resuscitation, compared with pulmonary blood flow, throughout the study (r = 0.549), matching only at baseline and at the end of both graded hemorrhage and resuscitation periods. There was a good correlation between ICO and pulmonary artery blood flow (r = 0.964) and no significant differences between them throughout the study. CONCLUSION: CCO has a delayed response during acute hemodynamic changes induced by hemorrhage and resuscitation. When sudden changes in mean arterial pressure or in mixed venous oxygen saturation are detected, cardiac output must be estimated by the standard bolus thermodilution technique, not by CCO.

Animals↗
PubMed1998

Use of pentastarch solution in the treatment of patients with hemorrhagic hypovolemia: randomized phase II study in the emergency room.

This study evaluates the hemodynamic effects of the administration of 10% pentastarch solution (PS) during the initial treatment of hypovolemia in trauma patients. This prospective randomized phase II study included trauma patients admitted to the emergency room with hemorrhagic hypovolemia: systolic blood pressure (SBP) < 90 mmHg. Upon admission, the patients were randomized to receive 10% PS (n = 12) or isotonic 0.9% NaCl solution (IS) (n = 11), infused intravenously in 250-ml boluses, repeated until SBP > 100 mmHg. Blood pressure, infused volumes necessary to maintain SBP, and overall survival rates were determined and compared between groups. SBP increased significantly following either IS (from 64.4 +/- 9.2 mmHg to 111.1 +/- 6.3 mmHg), or PS (from 63.7 +/- 10.6 mmHg to 108.1 +/- 9.8 mmHg) when compared to admission values (p < 0.05). Endovenous volumes infused were greater (p = 0.001) in IS patients (1420 +/- 298 ml) than in PS patients (356 +/- 64 ml). No blood was transfused into PS patients, compared to 370 +/- 140 ml of red blood cells transfused into IS patients (p = 0.015). Mortality rates were similar in the two groups (p = 0.725). We concluded that PS is a safe, efficient method for inducing hemodynamic recovery of hypovolemic trauma patients, with a clear reduction in the intravenous volumes required for acute resuscitation.

Adolescent↗
PubMed1998

Hemodynamic and metabolic effects of CO2 pneumoperitoneum in an experimental model of hemorrhagic shock due to retroperitoneal hematoma.

BACKGROUND: Diagnostic laparoscopy has been used in abdominal trauma patients, although its role is not well defined. The safety of laparoscopic evaluation in trauma patients with severe intraabdominal hemorrhage has not yet been analyzed. The purpose of this study is to evaluate the hemodynamic and metabolic effects of CO2 pneumoperitoneum (COI) in hemorrhaged animals through a retroperitoneal hematoma (RH). METHODS: Twenty-two 15-20-kg mongrel dogs were monitored for systemic and pulmonary hemodynamics, inferior vena cava pressure, and arterial blood gases. After 1 h of baseline, all animals were submitted to a RH. After 45 min the dogs were randomized into two groups. Control (CTR): dogs were submitted only to a RH; pneumoperitoneum (PN): dogs were submitted to a RH and 45 min later they were insufflated to an intraabdominal pressure of 10 mmHg with medical-grade CO2 gas for 30 min. Echocardiography was performed, only in PN animals, at baseline, 45 and 60 min after RH. RESULTS: RH induced a shock condition with low, sustained levels of arterial pressure, cardiac index, left ventricular stroke index, base excess, and oxygen delivery which were further depressed following COI. Three deaths occurred in the PN group, all of them toward the end of COI. During COI, hypercapnia was observed in one animal. COI did not impair systolic function or ejection fraction. CONCLUSIONS: COI with an IAP of 10 mmHg may be deleterious in animals with hemorrhagic shock due to an intraabdominal lesion. These findings could be clinically significant in abdominal trauma patients.

Animals↗
PubMed1998

Is aortic occlusion advisable in the management of massive hemorrhage? Experimental study in dogs.

Occlusion of the thoracic aorta is meant to improve cerebral and cardiac perfusion in the moribund, exsanguinating trauma patient. Yet clinical and experimental experience shows no evident benefit from this critical maneuver, and hind limb paralysis (HLP) is a feared complication. Our study is intended to verify whether aortic occlusion can decrease further blood loss and therefore be useful during treatment of hemorrhagic shock. Four groups of 10 dogs were submitted to hemorrhagic shock and treated with blood (40 mL/kg) and saline (35 mL/kg). Group I was then submitted to intermittent intra-aortic occlusion (IIAO), Groups II and III to IIAO and to a second bleeding (rebleeding), and Group IV to rebleeding only, without IIAO. All dogs received volume replacement during this rebleeding phase and were kept alive for 8 days. Five dogs died and seven had HLP in the three groups submitted to IIAO. Death and HLP occurred even in the dogs of Group I, which were not submitted to a second bleeding. IIAO reduced blood loss from 139 mL/kg to 48 mL/kg. There were no complications or deaths among the 10 dogs in Group IV. Although efficient in reducing blood loss, IIAO was associated with a 16% mortality and 23% of HLP, whereas volume replacement alone was tolerated without complications or death. We conclude that IIAO is dangerous while treating severe hemorrhagic shock even after volume replacement and hemodynamic stabilization.

Animals↗
PubMed1998

Hypertonic saline resuscitation.

Treatment of severe hemorrhage offers few theoretical problems, but in practice, severe blood loss usually occurs out of hospital, often in more or less inaccessible scenarios. Controversy rages over ideal fluid, ideal volume, and minimum O2 carrying capacity, but all agree that pre-hospital, isotonic resuscitation is unfeasible. The effects of highly hypertonic 7.5% NaCl (HS) was first described in 1980, when we showed that it induced immediate and long lasting hemodynamic restoration. The addition of 6% dextran-70 to (HSD) significantly enhances the duration and intensity of volume expansion, with no loss of hemodynamic effects. HS/HSD restores cardiac output, arterial pressure, base excess and oxygen availability, induce pre-capillary vasodialtion, moderate hyperosmolarity and hypernatremia, reversal of high glucose and lactate. It interferes with endocrine secretions when administered to animals in hemorrhagic hypotension. HS acts through transient plasma volume expansion, positive inotropic effect on cardiac contractility, precapillary vasodilation through a direct action on vascular smooth muscle. Expansion of circulating volume is part of the mechanism, the extra volume coming from the intracellular compartment fluid, especially from endothelial and red blood cells, which facilitate microcirculatory flow. The new field of interactions of hypertonicity with the immune mechanisms may provide insight into the long lasting effects of hypertonic solutions. Randomized double blind prospective studies on the effects of HS, or HSD, used as first treatment of shock show that both are safe and free from collateral, toxic effects. These studies show an early significant rise in arterial blood pressure and a non-significant trend towards higher levels of survival. HSD administration to patients about to undergo cardiopulmonary bypass for cardiac surgery results in higher cardiac output before, and immediately following cardiopulmonary bypass, as well as zero fluid balance.

Animals↗
PubMed1997

Prognostic factors to predict outcome following the administration of hypertonic/hyperoncotic solution in hypovolemic patients.

Hypertonic solutions effectively improve hemodynamic parameters in patients admitted to the emergency room. However, no significant differences in outcome were observed compared with standard isotonic treatment in most previously published studies. This study evaluates pretreatment prognostic factors that predict a beneficial effect of hypertonic solution in patients admitted to the emergency room with hemorrhagic hypovolemia in a prospective double-blind fashion. The patients (n = 212) were randomized upon admission to receive 250 mL intravenous (i.v.) bolus of hypertonic 7.5% NaCl + 6% dextran (HSD, n = 101), or isotonic 0.9% NaCl solutions (IS, n = 111) as the first treatment, followed by standard resuscitation. Pretreatment factors assessed were sex, age, cause of hypovolemia, revised trauma score (RTS), Glasgow index, and mean arterial pressure (MAP) on admission. Both groups were compared for survival at 24 h and 30 days postadmission. Infused volumes were registered. HSD administration significantly increased MAP and reduced i.v. crystalloid infusions to maintain hemodynamic parameters, compared with IS. There was no difference between groups in the number of blood transfusions administered. Overall complication rates in both groups were similar (24%). There was a significant difference (p < .03) in overall (30 days) survival rate between HSD (73%) and IS (64%) groups. The 24 h survival rate was significantly lower in IS (72%) compared with HSD (87%); p < .01. Multivariate analyses showed that RTS and MAP were identified as independent predictors for 24 h survival in the group that received HSD. When evaluated for overall survival rate, hypertonic infusion benefited significantly only patients with MAP < 70 mmHg (p < .01).

Adolescent↗
PubMed1993

Isochloremic hypertonic solutions for severe hemorrhage.

Two different hypertonic (2400 mOsm/L) isochloremic dextran solutions (sodium acetate, HAD; and sodium lactate, HLD; in 0.9% NaCl + 6% dextran 70) were compared with HSD (2400 mOsm/L NaCl + 6% dextran 70) as initial treatment for severe uninterrupted arterial bleeding. The substitution of dextran 70 for lactated Ringer's solution as the maintenance isotonic infusion fluid was also analyzed. Experiments were performed in pentobarbital-anesthetized dogs. A recently developed model, pressure-driven hemorrhage (PDH), which mimics uninterrupted arterial bleeding, was employed. It was found that (1) the substitution of dextran 70 for lactated Ringer's as isotonic fluid makes no difference in hemodynamic terms; (2) isochloremic hypertonic solutions are similar in their hemodynamic resuscitative effect, representing an improvement over hypertonic NaCl in terms of cardiac output, O2 delivery and O2 consumption; (3) HAD proved superior to HLD in terms of O2 consumption and correction of pH/base excess.

Acetates↗
PubMed1993

[Early hemodynamic effects of the rapid infusion of sodium chloride Dextran-70 hypertonic solution as treatment for hemorrhagic shock in dogs].

PURPOSE: To study the early hemodynamic effects of the rapid infusion of 7.5g/dl NaCl/ 6g/dl dextran-70 solution in dogs submitted to hemorrhagic shock. METHODS: Mongrel dogs were anesthetized with pentobarbital and a electromagnetic flowmeter probe was placed around the ascending aorta or the portal vein. By external bleeding the arterial pressure was lowered to 40mmHg and held for 30min. The animals received a 4ml/kg infusion of the hypertonic solution in 90s. Arterial blood pressure and flow were registered continuously during 3min and the derived hemodynamic variables were calculated at regular time intervals. RESULTS: The total plasma protein concentration decreased and the cardiac output showed a continuous elevation during the infusion. The arterial blood pressure showed two oscillations and then decreased during a short period of time. This moment was coincident with the initial increase of the portal flow and preceded the elevation of the systemic vascular resistance and the arterial pressure. CONCLUSION: The rapid infusion of hypertonic NaCl/dextran solution to dogs in hemorrhagic shock determines immediate and intense hemodynamic effects. During the infusion period there is volemic expansion and the cardiac output increases rapidly. The arterial pressure shows oscillations and decreases as a consequence of visceral arterial dilation before starting its final elevation that occurs as the vascular resistance increases.

Animals↗