Clifford M. Herman

Fat Release after Femur Nailing in the Dog

Internal fixation of fractures in the first few hours following injury has important advantages. It can diminish continued blood loss, improve patient mobility, and may help avoid pulmonary and cardiovascular complications of multiple trauma. Fear of increased risk of fat embolism has limited its use. We studied the release of fat during intramedullary reaming and nailing of the femur in dogs. Comparing fat release from an intact and a fractured femur in each dog, significantly more triglyceride was released from the intact bone than from the fractured femur. Thus, reaming a fractured bone produces minimal embolization. The presence of a fracture may decompress the pressure in the medullary canal, minimizing the release of fat into the circulation during acute internal fixation. This could help to explain the low incidence of clinical fat embolism syndrome associated with immediate intramedullary nailing of the femur.

Citrate anticoagulation and cell washing for intraoperative autotransfusion in the baboon

Extracorporeal citrate was used for anticoagulation during autotransfusion of baboons. A cell-washing plasmaphoresis procedure was added in one group of animals in order to remove activated clotting materials. Both groups became hypocoagulable, but the cell-washed group had less evidence of disseminated intravascular coagulation as well as lower plasma hemoglobin levels. Citrate anticoagulation plus cell washing is a potential alternative to heparinization for autotransfusion.

The role of peritoneal lavage in the management of stab wounds to the abdomen

In a 2 year period, 237 patients presented with stab wounds to the lower chest and anterior abdomen. Ninety-six patients were discharged from the emergency room after negative findings on wound exploration. There were no apparent missed injuries but two wound infections in this group for an overall morbidity of 2.1 percent. One hundred forty-one patients underwent exploratory laparotomy. Seventy-seven required emergency laparatomy because of hemodynamic signs of blood loss or peritonitis. Sixty-four patients whose only indication for laparotomy was penetration of the anterior abdominal wall fascia by local wound exploration underwent peritoneal lavage before laparotomy. If 50,000 red blood cells/mm3 in the lavage fluid had been used to select patients for observation, the incidence of negative laparotomy would have been reduced from 58 to 3.2 percent, and only one significant visceral injury would have been missed.

Benefits from improved oxygen delivery of blood in shock therapy.

Elevating erythrocyte 2,3-DPG and P50 has been proposed as a means of improving the delivery of oxygen by transfused blood. Fourteen baboons were resuscitated from hemorrhagic shock with either (A) 21-day-old blood with low P50 (20.2 mmHg ± SE 1.4) and 2,3-DPG (1.03 mm/liter ± 0.39), or (B) freshly shed autologous blood incubated 1 hr with pyruvate, inosine, glucose, phosphate, and adenine to elevate P50 (36.9 mmHg ± 1.2) and 2,3-DPG (5.00 mm/liter ± 0.33). Regressions of measured variables against P50 revealed: expected cardiac output down 18% for the observed increase in the P50 of the treated group; oxygen consumption up 9%; arterio-venous oxygen difference up 33%; and cardiac work down 24%. The P50 regression coefficients for these variables were different from zero (p < 0.05). It is concluded that administering blood with elevated 2,3-DPG and P50 furnished adequate tissue oxygenation at lower cardiac output and cardiac work than did 21-day-old blood.

Heparin versus citrate anticoagulation in autotransfusion.

Abstract Autotransfusion from controlled hemorrhage into a pelvic extraperitoneal pocket was performed in 19 baboons using a commercial autotransfusion apparatus. Nine heparinized animals (H) were compared to ten in which extracorporeal citrate plus cell-washing (CW) was employed. Serum hemoglobin levels were elevated in the H group but not in the CW group during autotransfusion. Elevated PT and PTT developed in both groups during autotransfusion with return to normal at 24 hr. Serum fibrinogen levels remained normal in the H group but were depressed in the CW group. Fibrin split products were more elevated in the H group than in the CW group. Interestingly, in the CW group total proteins were depressed with a disproportionate loss in the non-albumin fraction. The groups never differed from each other with respect to hematocrit, platelet aggregability, and serum total hemolytic complement levels. Both techniques provided adequate hypocoagulability for autotransfusion. The elevated PT, PTT , fibrin split products ( FSP ) and decreased fibrinogen represent a clear picture of disseminated intravascular coagulopathy in the H group. The lesser changes in the CW group suggest that the combination of citrate plus plasmaphoresis kept any intravascular coagulopathy at a more tolerable level in the CW group. The lower plasma hemoglobin levels in the CW group decreased the threat to renal function in the presence of marked hemolysis. These findings suggest that extracorporeal citrate plus cell-washing is an attractive alternative to heparinization of patients for autotransfusion.

The Relationship of Circulating Endogenous Endotoxin to Hemorrhagic Shock in the Baboon

Experiments were carried out to test the hypothesis that during hemorrhagic shock endotoxin enters the circulation from ischemic bowel by way of the portal venous system and is then associated with irreversibility of the hemorrhagic shock state. After placement of sampling catheters in the portal vein, right atrium, and aorta, 14 awake, restrained baboons were subjected to 1 hour of hemorrhagic shock at a mean arterial pressure (MAP) of 60 torr followed by a second hour at 40 torr MAP. Six animals were resuscitated with Ringers lactate and their shed blood; 8 were maintained hypotensive until death. Serial blood samples were analyzed for the presence of endotoxin. Endotoxemia was found infrequently, with no greater incidence (p > 0.6) in portal venous samples than in systemic blood, so these data were pooled for further analysis. Furthermore, endotoxemia was no more frequent (p > 0.6) late in shock than it was in early shock or during the baseline period. Autopsy showed no evidence of ischemic damage to the splanchnic viscera. It was concluded that spontaneous endogenous entotoxemia is not a common feature of hemorrhagic shock in baboons and is not related to the duration or degree of severity of hemorrhagic shock in this subhuman primate species.

Comparison of inulin and chromium-EDTA spaces in the nephrectomized baboon.

Summary The volumes of distribution of 14C-labeled inulin and Cr-EDTA have been compared in the nephrectomized baboon. The volume of distribution of inulin averaged 18.5 (±2.3)% of body weight with a range from 14.1 to 23%. Similar volumes for Cr-EDTA averaged 21.4 (±3.7)% of body weight with a range from 14.4 to 26.6%. No significant (p > 0.05) difference between the inulin and Cr-EDTA volumes was demonstrated. Plasma concentration of the isotope did not level off but continued to fall during the experiment. The gradual falling plasma-concentration curve was extrapolated to zero time in order to calculate extracellular fluid volume. It is concluded that when the extrapolation technique is used, the volumes of distribution of both inulin and Cr-EDTA adequately reflect the extracellular fluid volume in the nephrectomized baboon.

A critical appraisal of the effectiveness of scientific presentations.

Abstract A critical review was undertaken of onethird of the scientific presentations at the 1974 Annual Meeting of the Association for Academic Surgery. The purpose of this review was to determine the frequency with which scientific presentations failed to transmit information effectively. The data demonstrated that more than 50% of the surveyed presentations failed to transmit scientific data effectively.

Gastric Secretory Response to Acute Isotonic Hypervolemia.

Summary The effects of acute isotonic extracellular fluid volume expansion were studied in conditioned, anesthetized dogs who underwent pyloric ligation and creation of an external gastric fistula. A hypervolemic state was produced with intravenous Ringers lactate solution. The canine stomach responded as a “third-kidney” by significantly increasing gastric juice volume (528 per cent) and gastric acid output (696 per cent). This occurred paradoxically in the presence of a lactate load and a metabolic alkalosis.

The effect of sedation and awakening on energy substrates and hormonal relationships in the subhuman primate

Abstract Fifteen adult baboons were tranquilized with 1-(1-phenylcyclohexyl) piperidine hydrochloride (Sernylan) early in the morning and changes in hormonal levels and energy substrates were determined as the animal awoke. Serum-free fatty acids and plasma cortisol rose during the 4-hr observation period. This was accompanied by a similar rise in urinary catecholamines and 11-hydroxycorticosteroids. An elevation in serum glucose and a decrease in serum insulin were observed but these changes did not achieve statistical significance. Serum growth hormone decreased during the experimental period. These changes are discussed in relation to the use of the awake baboon for experimental shock studies.