A study of profound hypothermia by surface cooling

Abstract

Profound hypothermia below 20 ~ C achieved by surface cooling using simple ice water bath equipment and deep ether anaesthesia is used with the aid of autonomic nerve blocking agents to obtain cardiac arrest for periods of over one hour for open-heart surgery. Blood levels of ether were between 40.6 mgldl and 285.7 mg/dl during anaesthesia. No arrhythmia occurred and vital signs were quite stable. Hypocarbia throughout the procedure, severe base deficit after circulatory arrest, spontaneous recovery of metabolic acidosis, and a nearly normal cH + (pH) were observed. Catecholamine increased moderately after circulatory arrest, but was far below shock levels. Plasma renin activity was markedly elevated but angiotensin II stayed at non-significant levels throughout the procedure. Excess lactate showed no significant change. Hyperglycaemia was noted. The mortality rate was 7.7 per cent and neurological disorders occurred in less than 5.8 per cent of the recent 52 cases.UTILIZATION of total body hypothermia by simple surface cooling for the surgical repair of various cardiac lesions has recently been reevaluated, since bypass techniques pose a variety of problems to the haemodynamic and metabolic states of newborns and small infants. ~--6 Profound hypothermia by simple surface cooling tinder deep ether anaesthesia without bypass was carried out successfully at our institution for open-heart surgery in small infants and children to obtain cardiac arrest for periods of over one hour at a core temperature of below 2& C. Blood gases, acid-base balance and metabolism were studied during profound hypothermia by surface cooling under deep ether anaesthesia using specially devised equipment. Since 1962, 222 infants were operated upon under profound hypotherrnia by surface cooling at the hospital of the Kyoto Prefectural University of Medicine. The youngest patient was five months of age and the oldest six years, with a mean age of 29 months. Mean body weight was 11.8kg, and the smallest was 4.5 kg. The diagnoses are listed in Table I. Canad. Anaesth. Soc. J., vol. 27, no. 4, July 1980 promazine 0.4mg,kg -~. These were given intramuscularly one hour before anaesthesia and the patient was watched for 30 minutes. Atropine 0.015mg.kg-', diazepam 0.25mg.kg -1 and triflupromazine 0.4rag. kg -~ intramuscularly were added 30 minutes before induction. Heavy premedication is necessary to induce anaesthesia smoothly in a cyanotic infant.Anaesthesia was induced in infants by nitrous oxide, 50 to 67 per cent in oxygen with halothane 37O

Effect of temperature of insufflated CO2 during and after prolonged laparoscopic surgery

“…Plasma renin activity increases during hypothermia [13] and pneumoperitoneum [10,16]. In our study, plasma renin activity increased only during the warm pneumoperitoneum.…”