Effect of peripheral edema on cuff-based/ oscillometric blood pressure measurements accuracy

Abstract

Introduction: Blood pressure( BP )measurement is essential for epidemiological studies and clinical decisions . It seems that tissue characters can effect on BP  resultso and we try to find edema effect on BP measured  by three methods of oscillometric , auscultation and arterial . Method and materials:  Blood pressure of 55 children candidated  for open heart surgery were  measured  and compared with three methods : Arterial as standard and reference  ,oscillometric and auscultatory . Peripheral edema as an tissue character which defined as  higher than +2 as  marked edema and equal or lower than +2  considered as no edema . statistical  method :Data expressed by Mean (95% of confidence interval(CI 95%). Comparison between two group was done by T independent test and ANOVA test for more than two groups. Mann whitney U and paired T test test used for serially comparisons of methods  . P less than 0.05 is significant. Results: 55 children  aged  29.4±3.9 months ,they divided to two groups 10 children with  peripheral edema beyond 2+ and  45 cases without edema. Oscillometric method overestimate systolic BP  the Mean (CI 95%) difference of arterial to oscillomeric was 4.8(8/-1 , p 0.02) in edematous and 4.2(7/1 p 0.004) in non edematous. In diastolic BP oscillometric method underestimate -9(-1.8/-16.5, p0.03) in edematous group and 2.6(-0.7/+5,p 0.2) in non edematous. Conclusion : Oscillometric device standards can not cover all special clinical conditions and age groups .It  underestimate diastolic BP significantly in edematous children,  it was 9.2 mmHg in average as our study.

Keywords: Oscillometric, edema, Auscultatory