PERIPHERAL BLOOD FLOW IN INFANTS WITH HYALINE MEMBRANE DISEASE

Blood flow was studied by venous occlusion plethysmography in 13 infants requiring either continuous positive airway pressure (CPAP) or assisted ventilation for hyaline membrane disease. Infants were studied at one to 5 days of age. Individual infants were studied on up to 4 different days. The system used consisted of a blood pressure cuff applied to the thigh and a mercury strain gauge applied circumferentially to the mid-calf (Kidd et al, 1966). Arterial blood pressure (BP) was measured directly. Venous occlusion was accomplished by inflating the cuff to a pressure below that of the diastolic BP. Blood flow ranged from 3.8 to 14.3 ml/100 gm of tissue/ minute. For each infant, values were reproducible on a given day, but labile from day to day. The observed values were higher than those reported by Kidd et al, possibly because of changing practices regarding intravenous fluids and blood transfusion. Changes in blood flow could not be predicted from changes in BP, central hematocrit, or volume of blood withdrawn for laboratory studies. Blood lactate, base deficit or requirements for intravenous bicarbonate could not be predicted from blood flow. CPAP at pressures up to 6 cm H2O did not significantly reduce blood flow. A low blood flow in the first 24 hours suggested that blood transfusion was morelikely to be required subsequently during the course of the disease.