KH Wesseling | PubMed Health

PubMed1997

Increasing observer objectivity with audio-visual technology: the Sphygmocorder.

The most fallible component of blood pressure measurement is the human observer. The traditional technique of measuring blood pressure does not allow the result of the measurement to be checked by independent observers, thereby leaving the method open to bias. In the Sphygmocorder, several components used to measure blood pressure have been combined innovatively with audio-visual recording technology to produce a system consisting of a mercury sphygmomanometer, an occluding cuff, an automatic inflation-deflation source, a stethoscope, a microphone capable of detecting Korotkoff sounds, a camcorder and a display screen. The accuracy of the Sphygmocorder against the trained human observer has been confirmed previously using the protocol of the British Hypertension Society and in this article the updated system incorporating a number of innovations is described.

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PubMed1996

The elevation of forearm arterial blood pressureduring Riva-Rocci-Korotkoff measurements.

OBJECTIVE: To investigate why the forearm pressure rises above the systemic blood pressure upon the release of occluding cuff pressure during Riva-Rocci-Korotkoff blood pressure measurements and whether this overshoot could, as has been suggested, be used to predict the accuracy of Riva-Rocci-Korotkoff measurements in a certain patient. DESIGN AND METHODS: Finger arterial pressure was measured during Riva-Rocci-Korotkoff measurements on the same arm. Riva-Rocci-Korotkoff measurements were performed with different cuff deflation rates and after elevation of the arm, to study the nature of the overshoot reaction. Intra-arterial blood pressure was measured contralaterally. Vascular rigidity was measured by impedance plethysmography. RESULTS: Both diastolic and systolic blood pressure overshoots increased with increasing blood pressure, filling of the forearm circulation, pulse pressure, age and vascular rigidityh. They increased when lower, and decreased when higher, cuff deflation rates were used or when the arm was elevated before and during cuff inflation. Riva-Rocci-Korotkoff measurements were accurate, but finger pressures tended to underestimate the intra-arterial blood pressure in patients with high blood pressure overshoots. CONCLUSION: These findings are consistent with the hypothesis that the diastolic blood pressure overshoot results from increased filling of the forearm vasculature during Riva-Rocci-Korotkoff measurements. The systolic blood pressure overshoot probably results from pulse wave amplification in the partially occluded artery underneath the upper arm cuff. The overshoot phenomenon was not related to Riva-Rocci-Korotkoff errors.

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