Respiratory waveform variation can prevent pulsus paradoxus measurement by sphygmomanometry

Abstract

Background: Pulsus paradoxus (PP) represents increased fluctuation of systolic pressure during the respiratory cycle. PP increases in pathologic conditions, including asthma and other obstructive airways diseases. Respiratory waveform variation (RWV) represents arterial-waveform baseline variability resulting from intra-pleural pressure changes during the respiratory cycle in the presence of airway obstruction. It is not known whether RWV influences manual PP measurement using a sphygmomanometer and stethoscope. Methods: We performed an observational study in six healthy adults. Participants performed tidal-breathing through a breathing apparatus with pre-determined inspiratory (0–45.6 cm H₂O) and expiratory (0–24.4 cm H₂O) resistance levels for a total of 23 data sets per participant. PP was measured from continuous radial artery pressure recordings as the absolute difference between maximum and minimum systolic pressure levels during a complete respiratory cycle. Results: In this study, PP values measured without applied airway resistance exceeded 10 mmHg, the traditional definition of PP, in five of the six participants. Manual measurement of PP would not be possible at greater RWV because the maximum diastolic pressure exceeded minimum systolic pressure during RWV. Conclusions: PP in normal adults may exceed 10 mmHg, and RWV may be of sufficient magnitude to preclude manual PP measurement.

Keywords:

• Pathophysiology
• physiological disorders
• pulsus paradoxus
• blood pressure.

Disclosure statement

Dr. Arnold holds patent US 6,869 402 B2 licensed to Vanderbilt University by Precision Pulsus, Inc., assignee of the patent, and has an equity interest in Precision Pulsus, Inc. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

Dr. Arnold has grants from National Heart, Lung, and Blood Institute of the National Institutes of Health, outside the submitted work. Mr. Pologe reports grants from National Heart, Lung, And Blood Institute of the National Institutes of Health, during the conduct of the study. Ms. Wolley reports grants from National Heart, Lung, and Blood Institute of the National Institutes of Health, during the conduct of the study.