Quantification of physiological effect of respiration on automated measurement of blood pressure among normotensive adult individuals.

Background: Accurate blood pressure measurement necessitates meticulous methodology, as even minor variations like speaking or sitting can impact the readings. Additionally, respiration plays a role in blood pressure, exhibiting a dip during inhalation and a subsequent increase during exhalation. However, the influence of breathing patterns, duration, and rate on blood pressure remains largely unexplored.

Methods: In this study, we have attempted to quantify the changes in blood pressure and heart rate (HR) of normotensive individuals while performing predefined respiratory patterns - slow, medium, and fast (respiratory rates of 5, 10, and 20/m, respectively). For each respiratory pattern, age-matched and gender-matched (18-40 years) volunteered normotensive individuals were selected as volunteers. Baseline readings were recorded and each volunteer was randomly allotted a respiratory pattern. The volunteers performed the assigned respiratory pattern while the BP and HR were recorded.

Results: A fall in both SBP and DBP was observed in all three patterns of respiration. There was no inter-pattern difference in the blood pressure change. A novel finding in our study was a trend of respiratory rate and HR - the change in HR linearly increased with a rise in respiratory rate difference. We also proposed a linear regression equation for this increase in HR with the increase in respiratory rate which was statistically significant.

Conclusion: The findings suggest the decline in blood pressure is independent of the respiratory pattern employed. The study also demonstrates that the HR is a linear function of respiratory rate.