Acurácia e efetividade da medida de pressão arterial de consultório em condições ideais e não ideais de medição: ensaio clínico randomizado de equivalência entre os métodos auscultatório e oscilométrico

Abstract

The study aimed to evaluate the impact of non-ideal measurement conditions on the accuracy The study aimed to evaluate the impact of non-ideal measurement conditions on the accuracy of the office blood pressure measurement (BP) obtained in the auscultatory and oscillometric methods and to compare the effectiveness of the methods to classify BP and identify hypertension. Randomized clinical trial of equivalence conducted with 282 adults, between August 2019 and March 2020, in Fortaleza, Ceara. The arms were composed of three protocol deviations from the standardized BP measurement protocol, which, in this study, were called non-ideal measurement conditions: noisy environment, use of standard adult cuff size regardless of the patient's indication and combination of both. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) control measures were those obtained in the auscultatory method, fully following the standardized protocol. SBP and DBP measurements in the test condition were obtained by inserting protocol deviations during the measurement performed in the auscultatory methods, with an aneroid sphygmomanometer, and oscillometric, with automated monitor for clinical use. Auscultatory measurements were performed simultaneously by two observers and checked by a third, those with differences of less than 5 mmHg being considered valid. For each participant, six sequential measurements were obtained, interspersing aneroid and monitor, of which the first two were in ideal conditions and the next one in non-ideal. Mean difference tests were used in order to compare BP values obtained in the auscultatory and oscillometric methods. Bland-Altman plots were adopted to assess equivalence between methods. The protocol deviations had a greater impact on the auscultatory method and on the DBP (SBP: 0.57 mmHg x 0.20 mmHg; DBP: 3.29 mmHg x -0.92 mmHg, respectively for auscultatory and oscillometric). Use of a standard adult cuff resulted in a greater reduction in accuracy in both methods, compared to noisy environment. Smaller than adequate size generated similar overestimation of SBP between the methods and of greater DBP in the auscultatory. The automatic monitor met, under ideal and non-ideal conditions, the assumptions of equivalence, being as accurate as the manual sphygmomanometer when the BP measurement protocol is fully followed, as well as in situations where there are deviations related to cuff size and the presence of noise. Although auscultatory and oscillometric methods are equivalent, differences in accuracy naturally exist. In view of the protocol deviations, the accuracy of the auscultatory to classify BP values was 75.18% and the oscillometric, 74.82%; the effectiveness for identifying hypertension was 95.15% and 95.52%, respectively. In all test conditions, the oscillometric showed better diagnostic measures. It is concluded that automatic monitors and sphygmomanometers have equivalent accuracy in ideal and not ideal measurement conditions. In the face of protocol deviations, the methods showed similar effectiveness to classify BP values and identify hypertension. In these conditions, both methods have a greater predictive capacity for identifying individuals truly not hypertensive, to the detriment of identifying people with the disease. Identification in the Brazilian Clinical Trials Registry: U1111-1238-5001