Incerteza de Medição do Manômetro Usado em Esfigmomanômetros

Abstract

There is a growing interest on the measurement uncertainty determination for the conformity evaluation and quality assurance, mainly in the enviroment, safety and health sectors. In these areas the measurement result is considered critical since they deal directly with human beings. For the blood pressure measurement, according to studies accomplished in Australia, England and Brazil, a great concern is observed with the reliability of the results obtained by aneroid sphygmomanometers. In these studies, errors of up to 4,4 kPa (33 mmHg) were detected in the appraised sphygmomanometers, against the maximum value of 0,5 kPa (4 mmHg) standardized by OIML recommendation (R-16-1:2002). These errors result in a reduction of the sensitivity of hypertension diagnosis, with normal blood pressure patients being classified as hypertensive and vice versa. According to R-16, the evaluation of the reliability of these sphygmomanometers for medical diagnosis is obtained through the error measurement, and the uncertainty measurement is not required.

With the objective of contributing with an additional parameter to ensure metrological reliability of aneroid sphygmomanometers, it was developed a model for determination of the measurement uncertainty of the manometer used in these instruments. Based on the developed model, 15 aneroid sphygmomanometers were analyzed and the uncertainty of measurement of their manometers was determined. It was observed that, even when the error was within the allowed value of 0,5 kPa (4 mmHg), depending on the measurement uncertainty this limit could be exceeded, what can lead to incorrect clinical diagnosis.