Measurement of arterial closing pressure

It has been suggested that certain artifacts in blood pressure measurement by auscultation stem from stiffness of the tissues underneath the pressure cuff, resulting in a component of cuff pressure being required to overcome resistance to brachial artery collapse. This paper describes a technique for measuring the pressure required to collapse a segment of the brachial artery which has been isolated from central arterial pressure. This measurement is termed the arterial closing pressure. In a study of eleven elderly subjects, the artery collapsed spontaneously (zero closing pressure) after being isolated from central pressure 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 may contribute to error in the measurement of blood pressure by auscultation. 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 closure.