Análise comparativa da pressão arterial sistêmica por meio de três aparelhos distintos

Abstract

Introduction: Measurement of blood pressure is a common practice in clinical evaluation, independent of the specialty of care, recommended by the Brazilian Society of Hypertension in any and all health evaluations through validated and calibrated equipment. The purpose of this study is to analyze whether there are differences in systemic blood pressure values obtained by digital arm and pulse pressure devices when compared to the mercury column blood pressure device. Method: This is a cross-sectional, almost experimental, study carried out with servers of the rectory of two public universities. The simple random sample consisted of 223 individuals, aged 18 years or older, whose arm circumference measures between 18 to 36 cm and that of the wrist between 13.5 to 21.4 cm. For each participant, five blood pressure measurements were performed: three measurements with a mercury column sphygmomanometer, one with the digital arm and one with the digital pulse apparatus, according to the technique established by the VII Brazilian Hypertension Guidelines and the manufacturer of digital devices. Data collection took place between January and March of 2018, performed by a research team duly trained and blind to each other in relation to readings of BP measurement. The data were organized in the Statistical Package for Social Sciences (SPSS) version 21.0 and the statistical analyzes were done using the Minitab 17 program. Initially descriptive analyzes were carried out using the absolute (n) and relative frequency (%) for the categorical variables. In the analysis of the quantitative data, the mean and the standard deviation (Dp) were calculated for the variables that presented normal distribution through the Shapiro-Wilk test. In the rejected hypotheses of normality the median, quartiles (Q1 and Q3) and the interquartile range, which is the difference between Q3 (75%) and Q1 (25%), were calculated. The non-parametric test of Mann-Whitney and Kruskal-Wallis was applied in the comparison of medians. In order to evaluate the relationship between the quantitative variables that did not present a normal distribution, the Spearman correlation coefficient was applied and the t-student test was applied to verify the correlation hypothesis equal to zero. For the analysis of the limits of agreement between the values of systolic blood pressure (SBP) and diastolic arterial (DBP), determined by the different methods of blood pressure measurement, the Bland and Altman method was used. Results: The study included 223 participants, with a median age of 35 years, most of them women (61.9%). The analysis showed that the median SBP was similar between arm and wrist digital apparatus compared to the mercury column sphygmomanometer. However, there was a statistically significant difference in the DBP for the digital pulse apparatus greater than 4 mmHg compared to the mercury column sphygmomanometer (p <0.001). The correlation and agreement between the digital arm and pulse apparatus were strongly positive, (p <0.001), however, the readings obtained with the digital arm device presented greater similarity with the readings of the mercury column sphygmomanometer. The absolute difference of the readings within 5 mmHg between the arm digital apparatus and the mercury column were 52% and 71% for SBP and DBP, respectively. While the absolute difference of the readings within 5 mmHg between the digital pulse apparatus was 55.2% for SBP and 48.9% for DBP. A variability of 2 to 3 mmHg was observed between the readings for both in the participants with high BP. Conclusion: The study revealed that the digital devices tested showed strong positive correlation and high agreement with the sphygmomanometer mercury column. In the readings of both devices tested, it suggests that health professionals should exercise caution in the use of digital devices in the case of individuals with high BP, avoiding the use of the wrist device, even if these devices offer portability and convenience.