Erysod, erythrocyte superoxide dismutase preparation: effects on LPO processes and morphological changes in the viscera of rats with burns under conditions of delayed antishock infusion therapy

Biochemical and morphological changes in the kidneys, liver, heart, and lungs were studied in rats with deep burns of 20% body surface. Erysod (0.47 mg/kg/day) added to antishock therapy notably reduced the intensity of LPO processes in tissues both in cases when infusion therapy was started immediately (by 8-20% 12 h and by 5-24% 24 h after the injury) and when this therapy was 6 h delayed (by up about 36% after 12 h). This prevented injuries to visceral organs during the acute period of thermal injury and prevented the development of burn disease.

Sigmoid colonic reflectance pulse oximetry and tonometry in a porcine experimental hypoperfusion shock model

BACKGROUND

The objective of the present study was to determine if colonic endoluminal mucosal oxygen saturation, as determined by reflectance pulse oximetry, is an appropriate method to monitor colonic ischemia produced by a gradual partial constriction of the aorta in a porcine experimental model.

METHODS

Piglets were anesthetized and mechanically ventilated. A Nellcor RS-10 reflectance pulse oximeter probe was attached to a Foley balloon catheter and passed transanally to record the oxygen saturation of the sigmoid colonic mucosa. For comparison, a tonometry catheter was introduced into the sigmoid colon. Hypoperfusion shock was induced by partial gradual constriction of the aorta. The same measurements but no intervention was performed in the control group.

RESULTS

During one-third reduction of the aortic blood flow, the plethysmographic signal disappeared suddenly and the sigmoid colonic mucosa oxygen saturation (ScO2) measurements showed zero in seven out of the eight pigs. During two-thirds flow reduction, no plethysmographic signals were observed in any of the piglets. During the reperfusion period, ScO2 measurements with a good plethysmographic signal were obtained immediately after complete release of the aortic constriction in all pigs. Significantly decreased intramucosal pH and increased difference between the arterial and regional PCO2 (PCO2 gap) were observed during two-thirds blood flow reduction.

CONCLUSION

In contrast to the results of previous investigations, the sigmoid colonic pulse oximetry was not useful because the method proved to be overly sensitive and non-linear in relation to regional blood flow.

Effect of Erysod (erythrocyte superoxide dismutase) on blood concentration of reactive oxygen species in patients with severe burns and burn shock

The dynamics of blood concentrations of reactive oxygen species and LPO products in patients with thermal injuries of different severity was studied. Monitoring of these parameters by chemiluminescent and spectrophotometric techniques helps to predict the course of burn shock and prevent complications. Erysod (0.004% solution, 33-66 microg/min, daily dose 24-32 mg) added to antishock infusion therapy during the early periods after injury suppressed generation of free radicals (by 20% after 15 min and by 30-40% after 24 h), promoted normalization of their contents, and reduced damage to visceral organs during acute period of thermal injury.

Murine tumor necrosis factor-alpha sensitizes plasma corticosterone activity and the manifestation of shock: modulation by histamine

Murine tumor necrosis factor-alpha (mTNF-alpha) results in the sensitization of mechanisms underlying plasma corticosterone activity and sickness behavior, the latter being reminiscent of septic or anaphylactic shock. The mTNF-alpha induced a sensitization of sickness and corticosterone in mice that was attenuated by pretreatment with the combinations of histamine H(1) (diphenhydramine, mepyramine) and H(2) (cimetidine) antagonists. Likewise, coadministration of diphenhydramine and cimetidine prevented the mTNF-alpha-provoked rise of monoamine activity within the posterior hypothalamus. Although dexamethasone ameliorated the mTNF-alpha-induced sensitization of corticosterone, illness behavior was unaffected. It is suggested that mTNF-alpha-induced illness and the neuroendocrine sensitization are mediated by endogenous histamine.

Pancreatic involvement during the early phase of shock

BACKGROUND

There is a lack of data concerning pancreatic involvement during shock.

AIM

To evaluate possible pancreatic alterations in the early phase of shock.

SETTING

Twelve consecutive patients with shock were studied within 2 hours from the onset of illness. Seven patients died during the hospital stay: 3 within 4 hours from admission, 3 within 4-8 hours and 1 within 12 hours.

MAIN OUTCOME MEASURES

Amylase, lipase, C-reactive protein, amyloid A, interleukin 6, procalcitonin and vascular cell adhesion molecule-1 serum concentrations were determined on admission and 4, 8, and 12 hours afterward. All patients underwent imaging studies of the pancreas.

RESULTS

None of the patients developed clinical signs or morphological alterations compatible with acute pancreatitis. Serum amylase levels were above the upper reference limit in 7 patients (58.3%) and serum lipase levels in 2 patients (16.7%; P=0.062). There were no significant differences found between survivors and non-survivors in the serum concentrations of all the proteins studied.

CONCLUSIONS

In patients with shock, amylase seems to be more frequently elevated than lipase. None of the patients showed pancreatic alterations at imaging techniques.

Procalcitonin and neopterin as indicators of infection in critically ill patients

BACKGROUND

: In critically ill patients, severe infection and systemic inflammation due to non-infectious causes produce very similar clinical presentations, and traditional infection markers do not always differentiate these two conditions. Both procalcitonin and neopterin have been suggested to aid in the early diagnosis of bacterial infections and in differentiating bacterial infections from systemic inflammatory, non-infectious diseases or from viral infections.

METHODS

: Procalcitonin (PCT) and neopterin were analyzed in 208 ICU patients who developed acute fever or septic shock. Blood samples were taken every 8th h within 48 h of the onset of fever or septic shock.

RESULTS

: A total 162/208 of patients had infection, the most common location being the respiratory tract. Mortality was higher in infected patients (31.4% vs. 10.9%; P < 0.01). The optimum cut-off levels in identifying patients with infection of daily peak PCT were 0.8 microg/L on day 1 and 0.9 microg/L on day 2, and both sensitivity (67.7% and 60.9%, respectively) and specificity (47.8% and 63%) were poor. Accordingly, the optimum cut-off values of peak neopterin were 18 and 16 pg/L. The sensitivity was 62.7% on day 1 and 69.3% on day 2, while specificity was correspondingly 78.3% and 67.9%. There were no significant differences between the markers in discriminating between patients with infection or inflammation. Both PCT and neopterin increased with the severity of infection. They were higher in non-survivors.

CONCLUSION

: PCT and neopterin were equally effective, although not very accurate in differentiating between infection and inflammation in critically ill patients. Neopterin was more specific than PCT, suggesting that neopterin is related to the activity of inflammatory response.

Administration of two macrophage-derived interferon-gamma-inducing factors (IL-12 and IL-15) induces a lethal systemic inflammatory response in mice that is dependent on natural killer cells but does not require interferon-gamma

Activation of macrophages by microbes results in the rapid production of monokines (e.g., interleukin-12 (IL-12), IL-15, and IL-18), which induce production of interferon-gamma (IFN-gamma) by natural killer (NK) cells. We examined the effects of administering IL-15 in combination with IL-12 in a murine toxicity model to determine how these two cytokines might contribute to the inflammatory state that accompanies infectious processes. The daily, simultaneous administration of IL-15 (3 x 10(5)U) and IL-12 (1 microg) to normal mice resulted in shock and 100% mortality within 3-7 days, whereas minimal toxicity was observed following the administration of IL-15 or IL-12 alone. Mice treated with IL-15 plus IL-12 exhibited lesions of the gastrointestinal tract, elevated serum levels of acute phase reactants and pro-inflammatory cytokines, and NK cell apoptosis. Neutralization of IFN-gamma, TNF-alpha, and IL-1beta was not protective in cytokine-treated mice, however, toxicity and death could be completely abrogated by depletion of NK cells. Mice deficient in the STAT4 transcription factor also exhibited complete protection while mice deficient in IFN-gamma or its downstream mediator, STAT1, did not. These findings suggest that cytokine- stimulated NK cells are able to promote systemic inflammation via the induction of STAT4-responsive genes other than IFN-gamma or TNF-alpha.

Nuclear factor-kappaB as a target of cyclosporin in acute hypovolemic hemorrhagic shock

BACKGROUND

Cyclosporin is an immunosuppressive drug that blocks Nuclear Factor kappaB (NF-kappaB) activation. We investigated the role of NF-kappaB in acute hypovolemic hemorrhagic (Hem) shock and the effects of cyclosporin in this model of experimental shock.

METHODS

Hem shock was induced in male anesthetized rats by intermittently withdrawing blood from an iliac catheter over a period of 20 min (bleeding period) until mean arterial blood pressure (MAP) fell and stabilized within the range of 20-30 mmHg. Two minutes after bleeding cessation, animals received intravenously cyclosporin (1 mg kg(-1)) or its vehicle. Survival rate and survival time were evaluated for 120 min after bleeding was discontinued. Plasma TNF-alpha levels were investigated at different time points after bleeding cessation. Moreover we investigated levels of TNF-alpha mRNA in the liver, vascular reactivity, liver NF-kappaB binding activity and levels of the inhibitory protein IkappaBalpha in the cytoplasm.

RESULTS

Hemorrhagic shocked rats died in 27+/-6 min following the cessation of bleeding, experienced a marked hypotension (mean arterial blood pressure=20-30 mmHg) and had enhanced plasma levels of Tumor Necrosis Factor-alpha (208+/-22 pg ml(-1), 20 min after the end of bleeding). Furthermore, aortas taken 20 min after bleeding from hemorrhagic shocked rats showed a marked hypo-reactivity to phenylephrine (PE: 1 nM-10 microM) compared with aortas harvested from sham shocked rats. Hem shocked rats also had increased levels of TNF-alpha mRNA in the liver (15-20 min after the end of bleeding). Electrophoretic mobility shift assay showed that liver NF-kappaB binding activity increased in the nucleus 10 min after the end of hemorrhage and remained elevated until the death of animals. Western blot analysis suggested that the levels of inhibitory protein IkappaBalpha in the cytoplasm decreased at 5 min after the end of bleeding. Cyclosporin inhibited the loss of IkappaBalpha protein from the cytoplasm and prevented NF-kappaB binding activity in the nucleus. Furthermore, cyclosporin increased survival time (118+/-7 min; P<0.01) and survival rate (vehicle=0% and cyclosporin=80%, at 120 min after the end of bleeding), reverted the marked hypotension, decreased liver mRNA for TNF-alpha, reduced plasma TNF-alpha (28+/-7 pg ml(-1)), and restored to control values the hypo-reactivity to PE.

CONCLUSIONS

Our results suggest that acute blood loss (50% of the estimated total blood volume over a period of 20 min) causes early activation of NF-kappaB which triggers an inflammatory cascade leading to a fatal outcome. Cyclosporin blocks NF-kappaB activation and protects against hypovolemic hemorrhagic shock.

Central venous oxygen saturation monitoring in the critically ill patient

In the initial treatment of a critically ill patient, blood pressure, heart rate, urine output, and central venous pressure guide resuscitative efforts. Despite normalization of these variables, global tissue hypoxia may still persist and has been implicated in the development of multiorgan failure and increased mortality. Definitive management includes intensive care unit admission, pulmonary artery catheterization using mixed venous oxygen saturation (SvO2), and hemodynamic optimization. In the absence of or before definitive management, hemodynamic optimization can be performed using central venous oxygen saturation (ScvO2) as a surrogate. The physiology, technology, clinical uses, and rationale for ScvO2 monitoring are reviewed, including issues regarding physiologic equivalence to SvO2. The clinical use of ScvO2 monitoring, evidence-based outcome implications, and limitations of ScvO2 monitoring will also be examined.

Quantitative assessment of a circulating depolarizing factor in shock

Sustained depolarization of cell membranes and cellular edema are known to accompany various forms of circulatory shock and probably contribute to hypovolemia and cellular dysfunction. It has been proposed that a circulating protein is responsible for these effects. In the present study we have confirmed the existence of a circulating depolarizing factor (CDF) in hemorrhagic shock, burn shock, sepsis, and cardiopulmonary bypass. Plasma samples from pigs or sheep in shock were quantitatively assayed for depolarizing activity using a microelectrode method on rat diaphragm in vitro. The depolarizing effect of CDF in vitro was similar in magnitude to that of shock in situ. We conclude that CDF can entirely account for membrane depolarization during shock. The depolarizing effect of CDF was dose-dependent and saturable; it could be reversed by rinsing the diaphragm with Ringer's or control plasma. CDF activity was detectable in plasma within 5 min after a severe scald and gradually increased over the next 25 min. Resuscitation of hemorrhaged pigs, but not burned sheep, eliminated plasma CDF activity.

Blood viscosity, hemodynamics and vascular hindrance in a rat model of acute controlled bleeding and volume restitution with blood or Haemaccel

BACKGROUND

Hemorrhage and volume restitution with commercially available solutions is followed by reduced blood viscosity. Consequent hemodynamic changes may arise not only from the reduced viscosity itself but also from changes in vascular geometry induced by autoregulation processes. Vascular hindrance reflects the contribution of vascular geometry to flow. Our aim was to explore the possible effects of blood volume restitution with Haemaccel or blood, on regional blood flow and vascular geometry.

METHODS

Under ketamine anesthesia, blood was withdrawn at a rate of 0.3 ml/min for 15 min followed by 15 min of stabilization. The shed blood or Haemaccel was infused at the same rate and volume as used for withdrawal. Hemodynamic measurements were performed using radioactive microspheres. Blood viscosity was measured with an Ostwald viscometer. Vascular hindrance was calculated as the resistance/viscosity ratio.

RESULTS

Volume replacement with Haemaccel (n=10), compared to blood (n=10), was followed by increased cardiac output and portal venous inflow (37.1 +/- 9.0 and 3.1 +/- 0.5 vs 25.9 +/- 6.8 and 2.2 +/- 0.9 ml x min(-1) x 100 g bw(-1), respectively; P<0.05), decreased viscosity (2.8 +/- 1.3 vs 3.7 +/- 1.3, respectively; P<0.01) and decreased peripheral and splanchnic arteriolar resistance (3.8 +/- 1.1 and 40.9 +/- 7.6 vs 5.2 +/- 1.7 and 61.1 +/- 29.5 mmHg x ml(-1) x min x 100 g bw, respectively; P<0.05). No significant differences between the groups were observed in vascular hindrance and cardiac output distribution.

CONCLUSION

Volume replacement with Haemaccel, compared to blood, induced increase in systemic and splanchnic blood flows, reflecting mainly changes in viscosity and not in blood vessel geometry. These results suggest no significant difference in overall activation of autoregulation process between volume restitution with blood or Haemaccel.

Protein S-100beta in brain and serum after deep hypothermic circulatory arrest in rabbits: relationship to perivascular astrocytic swelling

The aim of this study was to evaluate the relationship between the kinetic patterns of the protein S-100beta, an astroglial cell marker, and its immunohistochemical expression in the brain in rabbits that underwent cardiopulmonary bypass with deep hypothermic circulatory arrest. Fourteen New Zealand rabbits (weight, 3.1+/-0.25 kg) were anaesthetised, intubated and mechanically ventilated. Four animals were not connected to the cardiopulmonary bypass and served as controls. Ten animals were perfused according to a uniform protocol. After systemic cooling, deep hypothermic circulatory arrest was induced for 60 minutes. After reperfusion and rewarming, the animals were weaned from bypass and sacrificed. In the brain, astrocyte reactivity for S-100beta was evaluated immunocytochemically (DPC Immustain) and the serum concentrations of S-100beta were analysed using a commercially available immunoluminometric kit (Byk-Sangtec, Dietzenbach, Germany). In all experimental animals a significant increase of the serum concentration of the protein S-100beta was found immediately after reperfusion and the termination of cardiopulmonary bypass. In comparison with the control animals, increased staining of S-100beta was found in the astroglial cells and swollen astrocytic end-feet in the perivascular regions. There were fewer signs of neuronal cell injury of neurones in the hippocampus structure. In conclusion, astrocytic activation and S-100beta overexpression seems to precede the neurodegeneration following deep hypothermic circulatory arrest. The marked perivascular cell swelling may support the assumption of reperfusion injury of the astroglial cell complex that forms the blood-brain barrier, which may be indicative of the source of the released S-100beta into the blood stream.

Plasma activation during splanchnic arterial occlusion shock

During circulatory shock, activating factors for cells in the microcirculation can be detected in plasma. But the source of such activators has remained uncertain. We have demonstrated recently that homogenates derived from the pancreas but not other peritoneal organs activate naive leukocytes. Production of such activating factors can be blocked by a serine protease inhibitor. Thus, factors generated by pancreatic proteases may possibly produce cellular activation in vivo. Rats were subjected to 90 min of superior mesenteric and celiac artery occlusion followed by reperfusion (SAO shock). In addition, rats were subjected to SAO shock for 120 min, after a 60-min pretreatment prior to occlusion with either saline or the serine protease inhibitor Futhan (nafamostat mesilate, 3.3 mg/kg b.w.). A sham SAO protocol was carried out as a control. Cellular activation was tested by neutrophil pseudopod formation and NBT reduction. Plasma from SAO-shocked animals but not sham shock rats exhibited a significant increase (P < 0.001) in the activation of naive leukocytes. Futhan-treated animals subjected to SAO shock exhibited a significantly higher post-reperfusion blood pressure than non-treated animals (P < 0.005 for all time points greater than 120 minutes), as well as significantly greater survival (P < 0.001). Neutrophil pseudopod formation and plasma peroxide production, an additional index of cellular activation, were significantly lower in Futhan-treated SAO shock plasma (P < 0.05) than levels in non-treated SAO shock animals. These results demonstrate that activating factors for leukocyte are released in SAO shock and can be mitigated by pretreatment with the serine protease inhibitor Futhan. Proteolytically derived plasma factors released during SAO shock may contribute to leukocyte activation and ensuing organ dysfunction.

Transcutaneous oxygen and CO2 as early warning of tissue hypoxia and hemodynamic shock in critically ill emergency patients

BACKGROUND

Although cardiac and pulmonary function can be measured precisely, evaluation of tissue perfusion remains elusive because it usually is inferred from subjective symptoms and imprecise signs of shock. The latter are indirect criteria used to assess the overall circulatory status as well as tissue perfusion but are not direct quantitative measures of perfusion. However, noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) tensions, which directly measure skin oxygenation and CO2 retention, may be used to objectively evaluate skin oxygenation and perfusion in emergency patients beginning with resuscitation immediately after hospital admission.

OBJECTIVE

This study was a preliminary evaluation of tissue oxygenation and perfusion by objective PtcO2 and PtcCO2 patterns in severely injured surviving and nonsurviving patients; specifically, the aim was to describe time patterns that may be used as early warning signs of circulatory dysfunction and death.

DESIGN

Prospective descriptive study of a consecutive series of severely injured emergency patients.

SETTING

University-affiliated Level I trauma center and intensive care unit.

PATIENTS AND METHODS

Forty-eight consecutive severely injured patients were prospectively monitored by PtcO2 and PtcCO2 sensors immediately after emergency admission.

RESULTS

Compared with survivors, patients who died had significantly lower PtcO2 and higher PtcCO2 values beginning with the early stage of resuscitation. All patients who maintained PtcO2 >150 torr (19.99 kPa) throughout monitoring survived. Periods of PtcO2 <50 torr (6.66 kPa) for >60 mins or PtcCO2 >60 torr (8.00 kPa) for >30 mins were associated with 90% mortality and 100% morbidity.

CONCLUSION

PtcO2 and PtcCO2 monitoring continuously evaluate tissue perfusion and serve as early warning in critically injured patients during resuscitation immediately after hospital admission.

Time-pattern of lactate and lactate to pyruvate ratio in the first 24 hours of intensive care emergency admissions

Blood lactate elevation in critically ill patients commonly is taken as a sign of impaired tissue perfusion. Simultaneous elevation of lactate to pyruvate ratio (L/P ratio) may be helpful in discriminating between different mechanisms of hyperlactatemia and thus in determining the relevance of the finding. We studied prospectively the prevalence and the time pattern of hyperlactatemia and simultaneous L/P ratio elevation in 98 consecutive emergency admission patients in a 23-bed surgical-medical University Hospital intensive care unit. Blood lactate, L/P ratio, and blood gases were measured at 2-h intervals during the initial 24 h of intensive care unit admission. Hyperlactatemia (blood lactate over 2 mmol/L) was found in 48 (49%) patients, and the median peak value of the non-survivors was higher than that of the survivors [5.3 (interquartile range 1.9-7.5) vs. 1.9 (1.3-2.9) mmol/L, respectively, p = 0.003]. Hyperlactatemia at admission (n = 31) was associated with a higher hospital mortality than hyperlactatemia developing later (n = 17) (29.0% vs. 5.9%, P = 0.003). Sustained admission hyperlactatemia (>6 h) was associated with higher mortality than short-lasting hyperlactatemia (36.8% vs. 0%, P = 0.008). Simultaneously elevated L/P ratio (L/P ratio > 18; n = 16) was associated with higher mortality than hyperlactatemia with normal L/P ratio (n = 32; 37.5% vs. 12.5%, respectively, P = 0.03) and was found mainly in patients who had severe circulatory failure. The hyperlactatemia of patients with sepsis was not associated with L/P ratio elevation. We conclude that hyperlactatemia is common in emergency admission patients. Hyperlactatemia with L/P ratio elevation and lactic acidosis is likely to be associated with inadequate tissue perfusion. Hyperlactatemia persisting more than 6 h and simultaneous elevation of L/P ratio are associated with increased mortality.

Risks of intravenous administration of hypotonic fluids for pediatric patients in ED and prehospital settings: let's remove the handle from the pump

Fluid resuscitation of infants and children is a common management problem in prehospital and emergency department care. We present two cases of children who received 5% dextrose in water as the initial resuscitation fluid. Bolus administration of hypotonic fluid contributed to fatal outcomes in these cases. Recommendations are made for eliminating hypotonic fluids as stock items in both the prehospital and emergency department settings.

[Serum lactate level as a indicator of tissue hypoxia in severely ill patients]

Adequate oxygen supply to the tissues is of vital importance to survive critical illness and trauma. Shock can be defined as an imbalance between oxygen demand and oxygen supply. Clinical features of shock, like hypotension, tachycardia, cold clammy skin et cetera, are poorly correlated with presence of tissue hypoxia. A high lactate level is an early sign of tissue hypoxia. In severely ill patients tissue hypoxia is the most important cause of increased lactate levels. Increased blood lactate levels are related to increased mortality. Optimizing oxygen supply by fluid resuscitation is the intervention of first choice.

Role of bradykinins and nitric oxide in the AT2 receptor-mediated hypotension

Footshocks increases mean arterial pressure and heart rate. Systemic or intracerebroventricular (IVT) administration of losartan, a specific angiotensin AT1 receptor antagonist, not only inhibited the pressor response to footshocks but resulted in vasodepression. Peripheral or IVT administration of PD 123319, a specific angiotensin AT2 receptor antagonist, did not alter the haemodynamic response to footshocks. However, simultaneous blockade of angiotensin AT1 and AT2 receptors by combined systemic or central administration of losartan and PD 12319, eliminated the vasodepressor response to footshocks unmasked in losartan pretreated rats. Our data suggest that activation of peripheral or brain angiotensin AT2 receptor mediated the vasodepressor response to footshocks in the presence of angiotensin AT1 receptor antagonist. We studied the role of kinins and nitric oxide in the vasodepressor response observed after footshocks. The decrease in mean arterial pressure observed after footshocks in losartan treated rats was blunted by systemic or IVT administration of icatibant (HOE 140) or N(G)-nitro-L-arginine-methyl ester, indicating that peripheral or brain kinins and nitric oxide are involved in the hypotensor response to footshocks during angiotensin AT1 receptor blockade. Our results suggest a role for angiotensin AT2 receptor in the regulation of arterial blood pressure, possibly through the release of vasodilator autacoids such as bradykinins and nitric oxide.

Generation of in vivo activating factors in the ischemic intestine by pancreatic enzymes

One of the early events in physiological shock is the generation of activators for leukocytes, endothelial cells, and other cells in the cardiovascular system. The mechanism by which these activators are produced has remained unresolved. We examine here the hypothesis that pancreatic digestive enzymes in the ischemic intestine may be involved in the generation of activators during intestinal ischemia. The lumen of the small intestine of rats was continuously perfused with saline containing a broadly acting pancreatic enzyme inhibitor (6-amidino-2-naphthyl p-guanidinobenzoate dimethanesulfate, 0.37 mM) before and during ischemia of the small intestine by splanchnic artery occlusion. This procedure inhibited activation of circulating leukocytes during occlusion and reperfusion. It also prevented the appearance of activators in portal venous and systemic artery plasma and attenuated initiating symptoms of multiple organ injury in shock. Intestinal tissue produces only low levels of activators in the absence of pancreatic enzymes, whereas in the presence of enzymes, activators are produced in a concentration- and time-dependent fashion. The results indicate that pancreatic digestive enzymes in the ischemic intestine serve as an important source for cell activation and inflammation, as well as multiple organ failure.

Hypertonic saline dextran produces early (8-12 hrs) fluid sparing in burn resuscitation: a 24-hr prospective, double-blind study in sheep

OBJECTIVE

Resuscitation of large burn injuries must quickly restore and maintain cardiovascular function and fluid balance while minimizing secondary edema-related damage. We tested the hypothesis that two 4-mL x kg(-1) doses of hypertonic saline dextran (HSD; 7.5% NaCl/6% dextran-70) can produce prolonged reduction in fluid requirements after burn injury.

DESIGN

Prospective, pseudo randomized, double-blind study.

SETTING

Animal research laboratory.

SUBJECTS

Female adult Merino sheep (n = 12).

INTERVENTIONS

Sheep were given a 40% total body surface area full-thickness flame burn under halothane anesthesia. One hour after the burn, the conscious animals received an initial dose of 4 mL x kg(-1) HSD (n = 6) or normal saline (NS; NaCl 0.9%) (n = 6) intravenously during 30 mins. This was followed by lactated Ringer's solution, infused to a target urine output of 1 mL x kg(-1) x hr(-1) throughout the 24-hr study. A second 4-mL x kg(-1) dose of HSD or NS was started at 12 hrs, and infused during 5 hrs.

MEASUREMENTS AND MAIN RESULTS

Hourly urine output measurements were used to guide the infusion rate of the lactated Ringer's. The initial infusion of HSD 1 hr after the burn injury promptly restored cardiac index, promoted diuresis, and reduced fluid requirements compared with the NS controls (73% reduction for HSD relative to NS at 8 hrs). Subsequent rebound fluid accumulation resulted in similar net fluid balances in both groups within 12 hrs after the burn. The second dose of HSD, given at 12 hrs, was without effect on hemodynamics and fluid balance.

CONCLUSIONS

We conclude a considerable initial, but not sustained fluid-sparing effect of early HSD, and no effect of a late, slowly infused HSD dose in this two-dose regimen.