MEASUREMENT OF ARTERIAL CLOSING PRESSURE

It has been suggested that certain artifacts in blood pressure measure ment by auscultation stem from stiffness of the tissues underneath the pressure cuff, resulting in a component of cuff pressure being requir ed to overcome resistance to brachial artery collapse. This paper desc ribes a technique for measuring the pressure required to collapse a se gment of the brachial artery which has been isolated from central arte rial pressure. This measurement is termed the arterial closing pressur e. In a study of eleven elderly subjects, the artery collapsed spontan eously (zero closing pressure) after being isolated from central press ure in seven subjects. The remaining four required external pressures ranging from 4.6 to 10.7 kPa (35 to 81 mmHg) in order to collapse the artery. Thus arterial closing pressure may frequently be a significant fraction of arterial blood pressure in the elderly population, and ma y contribute an error in the measurement of blood pressure by ausculta tion. Arterial closing pressure may be a useful tool for investigating the origin of differences between indirect and direct blood pressure measurements, and also in the investigation of spontaneous arterial cl osure.