Quantitative analysis of the effect of clothing on the oscillometric waveform envelope and oscillometric blood pressure measurements

Abstract

Purpose To ensure accurate blood pressure (BP) measurement, it is important to follow guidelines, such as wearing the cuff on the bare arm. However, this recommendation is often challenging due to patients being dressed. This study quantitatively evaluates how wearing a cuff over clothing impacts BP accuracy using oscillometric waveform analysis. Methods BP was measured under three conditions: thick sleeve (3.5 mm), thin sleeve (1.5 mm), and bare arm. Oscillometric waveform envelopes (OMWE) were analyzed to extract features like maximum amplitude, width, and slope for each condition. BP measurements and extracted features from the bare arm condition were compared with those from each sleeve condition. Results The mean systolic blood pressure (SBP) and pulse pressure (PP) increased by 11.73 and 10.04 mmHg under thick sleeve conditions. These also increased by 4.308 and 4.731 mmHg under thin sleeve conditions (Thick: p < 0.001, Thin: p < 0.05). The mean of mean arterial pressure (MAP) and OMWE width increased by 5.039 and 5.059 mmHg under thick sleeve conditions (Thick: p < 0.025). The mean of maximum amplitude of OMWE under thick and thin sleeves decreased by 0.9428 and 0.4017 mmHg (Thick, Thin: p < 0.001). Diastolic blood pressure (DBP) increased under thick sleeve conditions; however, this was not statistically significant. Conclusion Wearing the cuff over clothing altered OMWE morphology, resulting in a lower, flatter shape similar to that seen in hypertensives. This significantly affected BP readings, particularly SBP. Therefore, following guidelines for cuff placement on bare arms is crucial for accurate BP measurement.