William Gill

Repeated Freeze–Thaw Cycles in Cryosurgery

FREEZING temperatures have been in use in surgery for many years as a means of local tissue destruction. Recent experimental investigation has shown that such freezing will give a reproducible area of cell death provided factors such as the temperature and the duration of application are constant. Additional virtues have been claimed for repeated, as opposed to single, freeze–thaw cycles in terms of the degree of tissue destruction. In his discussion on cryotherapy for oral cancer Gage1 states “repetition of the freeze will increase the certainty of cell destruction” and similar comments2,3 are frequent in the literature.

ALCOHOL INTOXICATION AND SERUM OSMOLALITY

The relation between serum osmolality and blood-alcohol was studied prospectively in 565 acute trauma patients. The two measurements were closely correlated. It is therefore possible to estimate the blood-alcohol from serum osmolality to assist in the clinical management of acutely injured patients.

INDICATIONS FOR EARLY HÆMODIALYSIS IN MULTIPLE TRAUMA

Abstract Renal function in 751 cases of multiple trauma was studied to define a level of function compatible with ultimate survival. Established definitions of renal failure were ignored. A daily renal index was calculated using urine volume, serum-creatinine, and blood-urea-nitrogen (B.U.N.). The data for 3600 patient-days were analysed on a computer. Probability of survival was less than 0.1 in patients with a creatinine >4 mg. per 100 ml. or a B.U.N. >80 mg. per 100 ml. or a renal index >3 on one occasion or >2 on two consecutive days. The renal index provided an earlier and more accurate prognosis in a significant number of patients when compared with the other variables. The impairment of renal function associated with death in the patient studied is considerably less than currently accepted criteria for haemodialysis. Dialysis to within the levels shown to be compatible with survival offers a method of reducing the high mortality. Clinical application of the renal index as an indication for early haemodialysis in major trauma is proposed.

A mathematical model for volume replacement in bleeding patients

Patients with massive hemorrhage of diverse etiology are still associated with a high mortality rate despite reaching hospital alive. A multitude of factors contribute to this disappointing outcome and include delayed diagnosis, difficult technical surgery, surgical inexpertise, a lack of dedicated operating rooms, and inadequate or inappropriate resuscitatory measures. Other problems may be encountered which are specifically related to massive transfusion. Anemia from inadequate red-cell replacement, bleeding diatheses, and serious hypothermia may occur. If these hurdles are surmounted the patient may still develop organ failure syndromes and sepsis with a grave prognosis. Daily encounters with exsanguinating injuries from blunt trauma have resulted in rigid resuscitation protocols based on predetermined proportions of blood components to form a composite infusate compatible with life. This permits essential surgical attention to be directed elsewhere in the early critical management. Previous mathematic approaches to transfusion have concentrated on exchange transfusions and have assumed constant blood volumes [lo]. For therapeutic value in a

Use of the umbilical vein to study the splanchnic and portal beds in shock and trauma: II. Metabolic studies.

Perumbilical portal vein catheters and arterial and central venous catheters were inserted in 16 patients recovering from trauma or other shock-producing events, and in 5 patients who later developed shock. This permitted serial measurement of blood gases, pH, and the levels of ammonia, lactate and certain other metabolites in all three circulatory systems simultaneously. Nine of the trauma patients were never in shock, had no liver disease or injury and consequently formed a baseline group for comparison with the shock patients. In the shock patients there was a significant degree of hypoxemia in the portal venous blood and an increase in the arterialportal oxygen saturation difference. Their portal venous blood showed a lower pH and a higher pCO(2) than did the portal blood of the patients who had never been in shock. In 3 of the 4 shock patients who died, the total blood lactate showed a greater increase in portal venous than in the arterial or central venous blood. In shock there was also an increase in portal venous blood ammonia which was later accompanied by increments in arterial and central venous blood ammonia. This suggests impairment of hepatic urea synthesis, allowing escape of ammonia through the liver. These phenomena, when added to the finding previously reported of an elevated portal venous pressure in some shock patients, lend support to the hypothesis that in certain cases of shock there is increased impedance to flow of portal blood through the liver with resultant stasis in the portal-splanchnic bed and ischemichypoxic hepatocellular injury.