Statistics from Altmetric.com
Normal breathing will cause fluctuations of left ventricular stroke volume and blood pressure due to changes in intrathoracic pressure during the breathing cycle. Pulsus paradoxus is defined as a decrease in systolic blood pressure of more than 10 mm Hg during inspiration. A severe exacerbation of asthma, tension pneumothorax or cardiac tamponade can result in pulsus paradoxus. We are all taught to look for pulsus paradoxus as a measure of severity, but we rarely perform this part of the examination because it is not easy to measure accurately; it is subjective with poor inter-rater reliability and is simply not practical. Even with a high-fidelity electronic stethoscope and audio video recording, manually measured pulsus paradoxus does not correlate with severity of acute asthma in children1 because of poor inter-rater reliability.
Pulse oximetry is now routinely used in acute medicine. Can this bedside tool help us assess the severity of an asthma exacerbation? Krishnan S et al have examined 285 patients with exacerbations of their asthma and have assessed the role of pulse oximetry in evaluating the presence of pulsus paradoxus.2 There are a number of criticisms of this paper, but it should make us refocus on this old sign. The research team trained triage nurses in the determination of presence of pulsus paradoxus. In this study, it was taken as qualitatively present if there …
Contributors We have both contributed to the concept and the writing of this editorial. RM wrote the initial article after discussion with CP and then the article was completed and edited by CP.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Commissioned; internally peer reviewed.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.