We have already reported that anxiety, restlessness, and laboured breathing associated with high altitude pulmonary cedema, which did not respond satisfactorily to oxygen therapy, were found to respond dramatically to intravenous morphine . Subsequently, hemodynamic studies in convalescents from high altitude pulmonary oedema suggested that the beneficial effect of intravenous morphine might partly result from reduction of the pulmonary blood volume due to redistribution of blood in the periphery (Roy et al., 1965).We now report that morphine also augments frusemide diuresis in high altitude pulmonary cedema and accelerates recovery. The probable mechanisms are discussed.
SUBJECTS AND METHODThere were 98 men, 18 to 38 years old, all plainsmen, of whom 22 were new arrivals at high altitude; 76 had been resident at high altitude for 4 to 17 months, and developed acute pulmonary cedema on their return to high altitude after a sojourn in the plains of 60 to 70 days; none had suffered from pulmonary cedema during their first trip to high altitude. Both new arrivals and former residents developed acute pulmonary cedema 24 to 96 hours after arrival at high altitude. The vulnerable altitude was 11,500 feet. There were 69 out of 98 who were also suffering from acute mountain sickness.All cases were treated locally at the same altitude (11,500 feet). Immediately on arrival at hospital, a pretreatment clinical and radiological examination of the chest was made, and was repeated every 24 hours until the chest was clear.The trial, which was controlled but not blind, then started. Treatment A was administered to 84, and Treatment B, to 14 from a random selection. Treatment A consisted of a single injection of morphine 15 mg. intravenously and frusemide 20 mg. intravenously every 12 hours on the first day, and frusemide 40 mg. orally every 12 hours on the second and third days. Treatment B consisted of Treatment A minus morphine.Received June 23, 1966. 709The patients remained in bed in the same environment throughout these three days. During this period fluid intake consisted of hot sweetened tea and milk from a fixed ration, and additional quantities of water as required. The caloric value (1200 calories) and sodium content (552 mg.) were constant for all patients. The intake of water could not be fixed on account of mountain sickness in the majority of cases.Urine collections were done under supervision and were carefully measured to the millilitre. The difference between the urinary output and the intake of fluid in ml. constituted the effective diuresis.More than one consideration, based on our previous experience, weighed with us in restricting the number in the control group on Treatment B. (1) Most of the cases of high altitude pulmonary cedema occurred under field conditions and were severe. Anxiety, restlessness, and laboured breathing, which had not responded to bed-rest and oxygen therapy, had been specifically relieved with morphine. When morphine was not used, or was used with restraint, there was an associated m...