Urine Output and Fluid Therapy During Anaesthesia and Surgery

To try to determine whether fluid therapy during surgery should be on a large or a small scale 23 patients and six control subjects were studied. The control subjects were fasted and transfused with 2 litres of Ringer-lactate solution in one hour, the volume of urine output being measured at intervals for four hours. The patients were transfused similarly under varying conditions of anaesthesia and surgery. The characteristic urine output during abdominal hysterectomy followed a low, irregular pattern, and this occurred whether or not substantial amounts of fluid were transfused. In two patients anaesthesia and minimal trauma were associated with oliguria. An established diuresis was altered by anaesthesia and inhibited by surgery. These results indicate that excess Ringer-lactate solution administered during surgery may not be excreted and that overtransfusion could easily occur.     

Screening for Malignant Hyperpyrexia

The methods used to screen patients for malignant hyperpyrexia at present are not sufficiently accurate. This paper reports more specific methods of detecting patients liable to develop malignant hyperpyrexia. A motor-point muscle biopsy is performed for histopathological examination and to detect muscle contracture in vitro after exposure to halothane and suxamethonium.     

Procaine in Malignant Hyperpyrexia

The caffeine contracture of normal human muscle, which has been used as a model for malignant hyperpyrexia, is greatly potentiated by halothane. Prior administration of procaine markedly reduces the halothane-potentiated caffeine contracture, and procaine given at the height of the contracture induces relaxation. Lignocaine, on the other hand, produces a variable response and sometimes increases the contracture.The muscle from a patient with an inherited susceptibility to malignant hyperpyrexia contracted spontaneously with halothane alone, and this contracture was reversed by procaine.These experiments support the therapeutic use of procaine in malignant hyperpyrexia.