Photocell oscillometer for measuring systolic pressure in newborn.

Abstract

The difficulty in hearing Korotkow sounds and in palpating the pulse in the newborn has led to the development of several alternative methods of determining systolic blood pressure. Woodbury 1 and Haselhorst 2 have obtained intra-arterial pressures through the umbilical artery. The flush method 3,4 depends on the flush of the blanched limb as the end-point and gives values a little lower than actual systolic blood pressure. A number of methods for determining systolic pressure employ oscillometers of various types to detect arterial pulsation. Ashworth et al. 5 used a second forearm cuff connected to xylol beads to indicate the onset of the pulse. Rice and Posener 6 use a second forearm cuff to transmit pulsation to a diaphragm which deflects a light beam which may be photographed. Schaffer 7 used impedance plethysmography to detect pulsation. Morse 8 has reported a method which uses a small, sensitive microphone imbedded in