The effect of albumin or crystalloid resuscitation on bacterial translocation and endotoxin absorption following experimental burn injury.

Burn injury induces immune suppression and increases susceptibility to infection. Hypoalbuminemia is an early and consistent finding following thermal injury and is independently associated with gastrointestinal dysfunction and increased rates of infectious morbidity. This study assessed the effects of albumin resuscitation on burn-induced immunosuppression, bacterial translocation, and absorption of gut endotoxin. Male Sprague-Dawley rats, presensitized to keyhole limpet hemocyanin (KLH), underwent a 20% dorsal scald burn injury, followed by laparotomy and IVC catheterization for fluid resuscitation. Animals were randomized to one of three resuscitative regimens: Ringer's lactate 3 ml/kg/% burn, Ringer's lactate 9 ml/kg/% burn, or 5% human albumin 3 ml/kg/% burn. Delayed hypersensitivity (DTH) responses to KLH were depressed 24 hr following injury (preburn 8.9 +/- 0.2 mm, post-burn 3.1 +/- 0.3 mm, P less than 0.001) and were significantly lower in animals in whom gram-negative bacterial translocation had occurred (2.3 +/- 0.4 vs 3.6 +/- 0.2 mm, P less than 0.005). Serum albumin levels were lower and rates of gram-negative bacterial translocation higher for those animals receiving low volume crystalloid resuscitation; animals resuscitated with albumin or high volume crystalloid experienced similar degrees of postinjury hypoalbuminemia and bacterial translocation. Uptake of radiolabeled endotoxin was maximal in animals resuscitated with albumin. Bacterial translocation is believed to be responsible for a significant number of late nosocomial infections following trauma. These data suggest that the adequacy of early resuscitation rather than the type of resuscitative solution is the more important factor in minimizing translocation.     

Critical Evaluation of Hypertonic and Hypotonic Solutions to Resuscitate Severely Burned Children: A Prospective Study

Children with thermal burns covering 30% or more of the body surface area were alternately resuscitated with either hypertonic lactated saline (HLS) or lactated Ringer's solution (LRS). Parameters sequentially measured and calculated included: 1) serum and urine electrolyte concentrations, 2) serum and urine osmolalities, 3) arterial blood gases, 4) total and fractional serum proteins, 5) blood urea nitrogen, complete blood count and blood sugar concentration, 6) changes in body weight, 7) sodium, potassium and water balance. The water load received by the HLS group was significantly less through 48 hours postburn (49% at 8 hours, 44% at 24 hours and 38% at 48 hours postburn). Although the HLS group received significantly more sodium than the LRS group, there was no difference in sodium balance at 48 hours postburn. This is explained by the fact that the HLS group, at 48 hours postburn, retained significantly less of the administered sodium load (69% vs. 83%). Positive water balance was significantly greater in the LR group for the first 48 hours postburn. This study suggests that current hypotonic fluid regimens for burn resuscitation contain water in excess of that required for proper resuscitation. Severely burned children may be safely and efficiently resuscitated with conventional salt loads and one-third less than usual water loads.     

Hypertonic saline attenuates end-organ damage in an experimental model of acute pancreatitis

BACKGROUND: Hypertonic saline (HTS) has been noted previously to reduce neutrophil activation. The aim of this study was to elucidate the effect of hypertonic resuscitation on the development of end-organ damage in an animal model of pancreatitis. METHODS: Pancreatitis was induced in Sprague-Dawley rats by intraperitoneal injection of 20 per cent L-arginine. Animals were randomized into four groups (each n = 8): controls; pancreatitis without intervention; pancreatitis plus intravenous resuscitation with normal saline (0.9 per cent sodium chloride 2 ml/kg) at 24 and 48 h; or HTS (7.5 per cent sodium chloride 2 ml/kg) at these time points. Pulmonary endothelial leakage was assessed by measurement of lung wet : dry ratios, bronchoalveolar lavage protein and myeloperoxidase activity. RESULTS: Animals that received HTS showed less pancreatic damage than those resuscitated with normal saline (1.0 versus 3.0; P = 0.04). Lung injury scores were also significantly diminished in the HTS group (1.0 versus 3.5; P = 0.03). Pulmonary neutrophil sequestration (myeloperoxidase activity 1.80 units/g) and increased endothelial permeability (bronchoalveolar lavage protein content 1287 microgram/ml) were evident in animals resuscitated with normal saline compared with HTS (1.22 units/g and 277 microgram/ml respectively; P < 0.02). CONCLUSION: HTS resuscitation results in a significant attenuation of end-organ injury following a systemic inflammatory response to severe pancreatitis.     

Resuscitation with albumin using BET formula keeps at bay fluid administration in burned patients. An observational study

BET (Biological Engineering Technology) formula uses fluids with high albumin concentration to resuscitate burn patients. It estimates fluid resuscitation as a function of Body Burned Surface Area (BBSA) (ml/h = BBSA (m²) × 220) and administers it through a combination of lactated ringer and 20% Albumin starting at a 1:1 relationship. The proportion of albumin is decreased every 8 h, and infusion rate is modified according to urinary output. The study’s purpose was to review resuscitation related variables of all burned patients treated in our unit using BET formula. We retrospectively analyzed all patients admitted to our critical care burn unit during a five year period. Only those admitted within the first 12 h post-burn injury were considered. 40 patients met all inclusion criteria. Resuscitation volume during the first 24 h was 2.58 ml/kg/%BBSA, significantly less than Parkland’s estimation (4 ml/kg/%BBSA; P < 0.05). Patients were successfully resuscitated showing a significant base excess increase and lactate clearance during the resuscitation period (base excess 120%; lactate 29%; P < 0.05). Burn related complications where: ARDS 27%, renal dysfunction 53%, wound deepening 20%, abdominal compartment syndrome 4.5%. In conclusion, BET formula is capable of resuscitating burn patients successfully, limiting fluid administration.     

Fluid requirements of severely burned children up to 3 years old: hypertonic lactated saline vs. Ringer''s lactate-colloid

Children with burns 30 per cent of the body surface area were entered into a prospective fluid resuscitation protocol using hypertonic lactated saline (HLS) or Ringer's lactate-colloid. The two resuscitation groups were subdivided into patients 3 years old and children >3 vears old.

The children under 3 years old required significantly more fluid and sodium during the first 48 h when calculations were made using body weight as the indexing factor. When fluid and sodium needs of paediatric age groups were calculated using body surface area as the indexing factor, significant differences in fluid and sodium requirements were no longer present between age groups. This suggests that these observed differences may reflect the difference in surface area to mass ratio for these age groups.

Children resuscitated with HLS require 23 per cent less fluid in the first 24h. If body weight is used for estimating fluid needs, clinicians should be aware of the differences in fluid requirements for children 3 years old compared with older paediatric patients. Formulas for estimating fluid needs are presented.     

Hypertonic lactated saline resuscitation reduces the risk of abdominal compartment syndrome in severely burned patients

BACKGROUND: Secondary abdominal compartment syndrome is a lethal complication after resuscitation from burn shock. Hypertonic lactated saline (HLS) infusion reduces early fluid requirements in burn shock, but the effects of HLS on intraabdominal pressure have not been clarified. METHODS: Patients admitted to our burn unit between 2002 and 2004 with burns > or =40% of the total body surface area without severe inhalation injury were entered into a fluid resuscitation protocol using HLS (n = 14) or lactated Ringer's solution (n = 22). Urine output was monitored hourly with a goal of 0.5 to 1.0 mL/kg per hour. Hemodynamic parameters, blood gas analysis, intrabladder pressure as an indicator of intraabdominal pressure (IAP), and the peak inspiratory pressure were recorded. Pulmonary compliance and the abdominal perfusion pressure were also calculated. RESULTS: In the HLS group, the amount of intravenous fluid volume needed to maintain adequate urine output was less at 3.1 +/- 0.9 versus 5.2 +/- 1.2 mL/24 h per kg per percentage of total body surface area, and the peak IAP and peak inspiratory pressure at 24 hours after injury were significantly lower than those in the lactated Ringer's group. Two of 14 patients (14%) in the HLS group and 11 of 22 patients (50%) developed IAH within 20.8 +/- 7.2 hours after injury. CONCLUSION: In patients with severe burn injury, a large intravenous fluid volume decreases abdominal perfusion during the resuscitative period because of increased IAP. Our data suggest that HLS resuscitation could reduce the risk of secondary abdominal compartment syndrome with lower fluid load in burn shock patients.     

Blood volume changes of the anaesthetized rat to a large burn or mock burn injury measured using a continuous measuring circuit

A scald burn injury of 40-60 per cent body surface area was applied to the sodium pentobarbitone anaesthetized rat. The cardiac output of the burn injury rats fell from 39.5 +/- 2.1 to 27.7 +/- 1.5 ml/min (P less than 0.001) while heart rate, mean arterial blood pressure and central venous pressures were little changed but the total peripheral resistance rose significantly. Cardiovascular function was unchanged in control, mock-burned rats. The blood volume was measured continuously using an extracorporeal circuit and was observed to fall significantly by 0.78 +/- 0.36 ml in 5 min (P less than 0.05) and 1.65 +/- 0.38 ml in 60 min (P less than 0.001) after burn injury. The falls in blood volume and cardiac output were virtually simultaneous, and had occurred by 5 min. It is proposed however that this fall in blood volume is not sufficient to cause the observed changes in cardiac output and that additional factors such as cardiac impairment may be responsible for these changes postburn.     

Fluid distribution and pulmonary dysfunction following burn shock

Respiratory function and body fluid changes were measured in 46 burned patients for up to 7 days postburn (DPB). The patients in this prospective study were divided into an HLS group [n = 17, burn size 61 +/- 0.5% BSA (mean +/- SEM), resuscitated with hypertonic lactated saline] and an iso-Na group (n = 29, burn size 60 +/- 4.5% BSA, resuscitated with lactated Ringer's solution). During DPB 3 to 5, the Respiratory Index (A-aDO2/PaO2), functional extracellular fluid volume (f-ECFV), an ratio of plasma volume to interstitial fluid volume (PV/ISFV) were increased in the iso-Na group compared with the HLS group. During the same period, the Respiratory Index and PV/ISFV correlated significantly; respiratory dysfunction was less in the HLS group. Nearly 50% of the iso-Na group required endotracheal intubation. Sodium loads were the same in both groups; the HLS group required less water. These results suggest that extracellular fluid distribution differs between the two treatments; HLS may be associated with ameliorated respiratory function not only because of less volume loading during resuscitation, but also because the PV/ISFV ratio is less than when lactated Ringer's is administered.     

高密度脂蛋白对严重烫伤大鼠肺功能的保护作用

目的了解高密度脂蛋白（HDL）对严重烫伤大鼠肺功能的作用及其机制。方法将Wistar大鼠分为对照组（15只）、烫伤组（60只）和HDL组（60只）。对照组大鼠不作处理；其余2组均造成30％TBSAIII度烫伤，伤后常规补液，其中HDL组伤后立即经尾静脉注入HDL（80mg／kg）。检测2组烫伤大鼠伤后12、24、48、72h血清胞间黏附分子1（ICAM—1）及肿瘤坏死因子α（TNF—α）的含量，并检测其动脉血二氧化碳分压（PCO2）氧分压（PO2）；观察大鼠伤后各时相点肺组织病理学变化。另检测对照组上述指标。结果与对照组比较，烫伤组大鼠伤后各时相点ICAM—1、TNF—α的含量及PCO，均显著升高（P〈0．05或P〈0．01），PO，显著降低（P〈0．05）。HDL组上述指标与对照组比较，差异无统计学意义（P〉0．05）；但与烫伤组比较，各时相点ICAM—1、TNF—α含量均显著降低（P〈0，05或P〈0．01）。伤后48h，烫伤组ICAM-1、TNF—α分别为（3．42±0．25）μg／L、（4．04±0．28）ng／L，明显高于HDL组[（2．24±0．14）μg／L、（3．35±0．22）ng／L，P〈0．05或P〈0．01]。烫伤组大鼠伤后48h肺小血管周围炎性细胞浸润，肺内血管扩张出血，部分小血管管腔内红细胞淤滞凝集，形成“假血栓”；肺毛细血管内皮细胞连接松弛，内皮细胞水肿。HDL组肺内小血管周围炎性细胞浸润明显减轻；肺毛细血管内皮细胞连接较紧密。结论HDL对严重烫伤大鼠肺功能具有保护作用，可能与其抑制ICAM—1、TNF—α表达有关。     

Changes in plasma fibronectin levels in burn patients

Plasma fibronectin was determined in 180 healthy individuals. No significant difference was found between males and females: therefore the values were pooled. The mean value was 286.94 +/- 51.35 micrograms/ml. In 24 patients with burns covering 30-95 per cent of the total body surface area (TBSA), plasma fibronectin was determined sequentially. There was a significant lowering in plasma fibronectin (FN) values in all cases on post-burn day 1 (112.56-185.85 micrograms/ml) and post-burn day 2 (44.03-298.0 micrograms/ml). The concentrations returned to within the normal range in 19 survivors within 3-6 days. In five non-survivors, plasma FN levels fell progressively until death. In another nine patients with burns ranging from 3 per cent to 25 per cent TBSA, plasma FN level was found to be normal on post-burn day 1. The likely causes of the reduced concentrations of plasma fibronectin in patients with burn injuries are briefly discussed. It seems that the level of plasma fibronectin may be used as a prognostic index in burn patients.     

High-dose vitamin C therapy for extensive deep dermal burns.

We studied the haemodynamic effects of antioxidant therapy with high-dose vitamin C administration (170 mg/kg/24 h) in guinea-pigs with 70 per cent body surface area deep dermal burns. The animals were divided into three groups of six animals each. Group 1 was resuscitated with Ringer's lactate solution according to the Parkland formula; group 2 with 25 per cent of the Parkland formula with vitamin C; and group 3 with 25 per cent of the Parkland formula without vitamin C. There were no significant differences in heart rates or in blood pressures between the groups throughout the 24-h study period. Group 3 showed significantly higher haematocrit values at 3 h postburn and thereafter as compared with those of group 2. The cardiac output values of group 2 were significantly higher than those of group 3, but equivalent to those of group 1. The water content of the burned skin in group 2 was significantly lower than that in the other groups, indicating that increased postburn capillary permeability was minimized by the administration of vitamin C. With adjuvant high-dose vitamin C administration, we were able to reduce the 24-h resuscitation fluid volume from 4 ml/kg/per cent burn to 1 ml/kg/per cent burn, while maintaining adequate cardiac output.     

Hypertonic sodium resuscitation is associated with renal failure and death.

OBJECTIVE: The use of hypertonic sodium solutions (HSS) and lactated Ringer's (LR) solution in the resuscitation of patients with major burns was compared. SUMMARY BACKGROUND DATA: Hypertonic sodium solutions have been recommended for burn resuscitation to reduce the large total volumes required with isotonic LR solution and their attendant complications. METHODS: To evaluate the efficacy of this therapy in our adult burn center, we resuscitated 65 consecutive patients with HSS (290 mEq/L Na) between July 1991 and June 1993 and compared them with 109 burn patients resuscitated with LR (130 mEq/L Na) between July 1986 and June 1988 (LR-1). A subsequent 39 patients were resuscitated with LR between September 1993 and August 1994 (LR-2). RESULTS: Patients receiving hypertonic sodium solutions versus LR-1 were similar with respect to age (46.0 vs. 43.6 years), total burn size (39.2% vs. 39.9%), incidence of inhalation injury (41.5% vs. 47.7%), and predicted mortality (34.6% vs. 30.2%). Total resuscitation volumes during the first 24 hours were lower among patients treated with HSS than those in the LR-1 group (3.9 +/- 0.3 vs. 5.3 +/- 0.2 mL/kg/% body surface area [BSA], p < 0.05). After 48 hours, however, cumulative fluid loads were similar (6.6 +/- 0.6 vs. 7.5 +/- 0.3 mL/kg/%BSA), and total sodium load was greater with the HSS group (1.3 +/- 0.1 vs. 0.9 +/- 0.1 mEq/kg/%BSA, p < 0.002). During the first 3 days after burn, serum sodium concentrations were moderately elevated in the HSS patients (153 +/- 2 vs. 135 +/- 1 mEq/L, p < 0.001). Patients resuscitated with HSS had a fourfold increase in renal failure (40.0 vs. 10.1%, p < 0.001) and twice the mortality of LR-1 patients (53.8 vs. 26.6%, p < 0.001). In patients resuscitated with HSS, renal failure was an independent risk factor (p < 0.001, by logistic regression). Analysis of these results prompted a return to LR resuscitation (LR-2). Age (41.6 +/- 2.9 years), burn size (37.8 +/- 3.9 %BSA), and incidence of inhalation injury (51.3%) were similar to the earlier groups. Total sodium load was less among LR-2 patients than the HSS group (0.7 +/- 0.1 mEq/kg/%BSA, p < 0.01), but similar to the LR-1 patients. Renal failure developed in only 15.4%, and 33.3% died, similar to the LR-1 group and significantly lower than patients treated with HSS (p < 0.001 and p < 0.05, respectively). CONCLUSION: Hypertonic sodium solution resuscitation of burn patients did not reduce the total resuscitation volume required. Furthermore, it was associated with an increased incidence of renal failure and death. The use of HSS for burn resuscitation may be ill advised.     

A qualitative and quantitative analysis of protein loss in human burn wounds

INTRODUCTION: It is well known that in patients suffering from major burn injuries of more than 15% of total body surface area (TBSA), capillary leak and loss of proteins including immunoglobulins (Ig) lead to cardiovascular failure and significantly elevated risk of infections. However, knowledge of the resulting protein profiles is limited. In order to elucidate quantitative and qualitative protein loss in human burn wounds we compared wound fluid (WF) protein content with serum protein levels. MATERIAL AND METHODS: Eleven patients suffering from second degree burns of 18-68% TBSA were enrolled in the study. Immediately after admission burn wounds were enclosed in cutaneous vinyl wound chambers covering a 2.25 cm(2) wound surface area. WF and serum samples were harvested every 8 h with a follow up of 48 h and analyzed for total protein content, albumin and the immunoglobulins A, E, G and M. RESULTS: Protein levels in serum were significantly lower as compared to physiological levels while WF protein levels were elevated and remained high. Total protein (TP) and albumin (AL) accumulated in high concentrations on the wound surface (average accumulation on 10% burnt TBSA within 8 h: TP=16.59+/-8.86 g; AL=12.39+/-5.87 g). The albumin fraction in WF showed increasing values (24 h: 69%; 32 h: 86%) although the serum albumin fraction remained nearly unchanged (55%). Peak values were initially found for all immunoglobulins both in serum and WF. IgA, E and M reached a steady state 32 h post-trauma, whereas IgG continuously decreased until 40 h. IgG values in serum were significantly below physiological levels at all time points. CONCLUSIONS: This study qualifies and quantifies a significant protein loss in second degree burn wounds. Protein concentrations in wound fluid correlate highly with serum concentrations until 48 h post-burn. A patient's entire amount of serum proteins accumulates in wound fluid in a 20% TBSA burn within approximately 24h. In contrast to capillary leak theory proteins and immunoglobulins extravasate to wound fluid even after 48 h post-trauma.     

Sepsis and antithrombin III, prekallikrein, and fibronectin levels in surgical patients

Antithrombin (AT), prekallikrein (PK), and fibronectin (FN) were measured in the plasma of 400 patients with a variety of disease states seen at Detroit Receiving Hospital from October 1983 through June 1987. The average lowest AT measured in these 400 patients was 69 +/- 19 per cent (SD) (Normal = 75-120%). The average lowest AT level in 152 septic patients (50 +/- 17%) was significantly lower than in the 248 patients without sepsis (79 +/- 22%) (P less than 0.001). The average lowest PK levels measured in 132 patients was 52 +/- 19 (Normal = 80-120%). The average PK level in 64 septic patients (34 +/- 17%) was significantly lower than in 68 who were not septic (69 +/- 21%) (P less than 0.001). The average lowest FN levels measured in 109 patients was 230 +/- 118 mcg/ml (Normal = 200-350 mcg/ml). The average FN level in 47 septic patients (162 +/- 88 mcg/ml) was significantly lower than in the 62 nonseptic patients (285 +/- 138) mcg/ml. AT or PK levels less than 50 per cent or FN levels less than 150 mcg/ml during the first 24 to 48 hours after severe trauma or burns were associated with a development of later sepsis in 90 per cent, 77 per cent, and 70 per cent, respectively. Thus, low or falling levels of AT, PK, and FN may be of great help in predicting sepsis or providing an early diagnosis in critically ill or injured patients.     

Effect of Dazmegrel (UK-38,485) on immune function in a burned guinea-pig model

We investigated the effects of Dazmegrel, a highly effective and selective thromboxane synthetase inhibitor, on the immune system in a bilateral 5 per cent total body surface area (TBSA) deep partial thickness scald in a guinea-pig model. The animals were randomized into two groups: one received Dazmegrel at 3.4 mg kg-1 day-1 by i.m. injection; the other received the same volume of saline. Cell-mediated immunity was evaluated by the response to the hapten dinitrofluorobenzene (DNFB), as measured by ear swelling in response to cutaneous application. The ear swelling of the Dazmegrel-treated group was 52.8 +/- 3.8 per cent, compared to 41.4 +/- 2.4 per cent for the control group (P less than 0.02). Neutrophil bactericidal function was determined on post-burn day (PBD) 7 and opsonic function on both post-burns days 7 and 22. The serum opsonic indices were nearly identical at both times, but the Dazmegrel-treated animals had a significantly improved neutrophil bactericidal index (1.15 +/- 0.05 v. 1.68 +/- 0.17, P less than 0.01). Dazmegrel exerted a stimulating effect on the immune system in this burn model, improving neutrophil antibacterial function and cell-mediated immunity.     

Influences of different resuscitation regimens on acute early weight gain in extensively burned patients

Dissatisfaction with the massive weight gain that commonly followed crystalloid resuscitation of extensively burned patients dictated the need for a study to determine if acute weight gain could be minimized with an alternative form of resuscitation. Three groups of ten patients each with statistically similar age and burn size (mean BSA 46 per cent) were resuscitated with lactated Ringer's solution (LR), hypertonic saline solution (HPT), or fresh frozen plasma (FFP). The volume of infused fluid and the patient weight gain were measured over the first 48 h of treatment. The mean urine output of the three groups was comparable (P greater than 0.05). The volume of infused resuscitation fluid to maintain urine output was a mean of 4.8 ml/kg/per cent BSA in the LR group, 3.16 in the HPT group and 2.68 in the FFP group. The difference in infusion rate between the FFP group and the LR group was statistically significant (P less than 0.01). All patients gained weight with resuscitation. The median percentage weight gain at the end of the first day of treatment was 10.69 per cent in the LR group, 7.88 per cent in the HPT group and 2.38 per cent in the FFP group. Weight gain at the end of the second day of treatment was 13.9 per cent in the LR group, 11.99 per cent in the HPT group, and 4.37 per cent in the FFP group. The differences between FFP, HPT and LR groups were statistically significant (P less than 0.01). In our study the use of fresh frozen plasma for resuscitation of extensively burned patients has been associated with minimal weight gain and minimal oedema. We believe that fresh frozen plasma resuscitation is an attractive alternative to crystalloid infusion and that further comparative studies should be performed.     

Maternal and fetal effects of prophylactic hydration with crystalloids or colloids before epidural anesthesia

Prophylactic intravenous hydration decreases the incidence and severity of hypotension due to obstetric epidural anesthesia. This study assesses whether infusion of normal serum albumin (NSA) offers any advantages over Ringer's lactate (RL) solution. Sixty patients scheduled for elective cesarean sections were divided into three equal groups. Group 1 received 1200 ml of RL; group 2, 700 ml of RL plus 500 ml of 5% NSA; and group 3, 1000 ml of RL plus 200 ml of 25% NSA. In group 1, the concentrations of serum albumin (SA) decreased from 3.5 +/- 0.3 (mean +/- SD) to 3 +/- 0.2 g/dL (P less than 0.01) and plasma oncotic pressure (POP) from 20 +/- 3 to 17 +/- 3 torr (P less than 0.005) immediately after hydration. In group 2, SA remained unchanged, but POP decreased from 21 +/- 2 to 19 +/- 2 torr (P less than 0.005). In group 3, SA increased from 3.6 +/- 0.5 to 3.9 +/- 0.3 g/dL (P less than 0.01) and POP from 19 +/- 2 to 21 +/- 2 torr (P less than 0.0025). Neither SA nor POP levels differed among the groups 24 h later; however, both SA and POP were significantly lower than preinfusion values in all groups at 24 h. The incidence of maternal hypotension, neonatal Apgar scores, and acid-base status also were comparable among the groups (X2 analysis). Because low POP may predispose to postoperative pulmonary morbidity, the incidence of this complication was studied in the mothers by using a point scoring system (based on the presence of symptoms and physical signs) and also by measuring AaDO2 gradients. Neither pulmonary morbidity scores nor AaDO2 gradients differed significantly in the three groups. It is concluded that both crystalloid and colloid prehydration produce equally satisfactory maternal and fetal outcomes.     

Elevation of albumin synthesis rates in nephrotic patients measured with [1-13C]leucine.

Eight patients with a nephrotic syndrome and a histologically-proven kidney disease were compared to age- and sex-matched healthy volunteers. Albumin synthesis rates were measured after injection of 13C-labelled leucine (57 mg/kg body wt, 19.4 atoms%). Plasma volume was determined with 125I-albumin. The fractional synthesis rate of albumin was 7.9 +/- 0.4%/day in control subjects in comparison with a marked elevation to 18.4 +/- 2.0%/day (P less than 0.001) in nephrotic patients. The absolute synthesis rate was 145 +/- 9 mg/kg/day in control subjects compared with 213 +/- 17 mg/kg/day (P = 0.005) in the nephrotic patients. There was a statistically significant correlation between ASR and urinary albumin loss (P = 0.035) and serum cholesterol concentration (P = 0.007). The calculated oncotic pressure was significantly lower in the nephrotic group than in the controls (P less than 0.001), but was without correlation with ASR.     

Atrial natriuretic polypeptide after burn injury: blood levels and physiological role in rats

To define the relationship between atrial natriuretic polypeptide and the physiological changes of water and electrolytes after burns, the changes in plasma hormonal levels, including atrial natriuretic polypeptide, and urinary water and sodium excretions were examined in burned rats. Further, to elucidate the physiological significance of atrial natriuretic polypeptide after burns, the effects of a specific antiserum against atrial natriuretic polypeptide were determined in burned rats. Plasma atrial natriuretic polypeptide levels in rats following 30 per cent BSA full skin thickness burns were elevated for sustained periods (432.3 +/- 156.5 pg/ml, P less than 0.01 on day 1 postburn, 244.5 +/- 73.7 pg/ml, P less than 0.05 on day 3 postburn). Urine volume and sodium excretion decreased significantly during the first 72 h after burns. On day 3 postburn, urine volume and sodium excretion began to increase significantly. Specific rabbit antiserum against atrial natriuretic polypeptide was injected into the burned rats during this diuretic phase. Significant inhibition of diuresis and natriuresis was observed after the injection of antiserum (27.5 +/- 2.4 per cen decrease in urine volume, 57.1 +/- 10.4 per cent decrease in sodium excretion). These results suggest that atrial natriuretic polypeptide plays a physiological role in the regulation of urinary water and sodium excretion after burns.     

U-74,500A inhibition of burn-induced cardiac dysfunction.

Our previous studies suggest that oxygen-derived free radicals, particularly the hydroxyl radical, play a major role in cardiac dysfunction which is characteristic of burn injury. In this present study, we examined the effects of U-74,500A (U7), a 21-aminosteroid, nonglucocorticoid on ventricular contraction and relaxation recovery from burn injury. Parameters measured included left ventricular pressure (LVP) and the maximal rate of LVP rise (+dP/dt max) and fall (-dP/dt max). Full-thickness burns comprising 45% of the total body surface area (burn groups, N = 69) or 0% for controls (Group 1, N = 8) were produced in guinea pigs. In Group 2, 20 burned guinea pigs were not fluid resuscitated (vehicle only) and served as untreated burns; in Group 3, 11 burned guinea pigs received U7 alone (2.5 mg/kg in 0.01 N HCl iv). Eleven burned guinea pigs were resuscitated with vehicle plus 4 ml lactated Ringer's (LR)/kg/% burn for 24 hr (Group 4); in Group 5, 14 guinea pigs were treated with U7 as described for Group 3 followed immediately by LR for 24 hr as described for Group 4. In Group 6, U7 was administered immediately postburn as described for Group 3; and LR resuscitation, begun 1 hr postburn, was continued for 24 hr (N = 14). Compared to controls, untreated burn injury significantly impaired cardiac function as indicated by a fall in LVP (74 +/- 3 vs 60 +/- 4 mm Hg, P less than 0.05) and +/- dP/dt max (1126 +/- 51 vs 1011 +/- 39 and 1159 +/- 53 vs 993 +/- 59 mm Hg/sec, P less than 0.05, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)