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Supplemental oxygen for pulmonary embolism (SO-PE): study protocol for a mechanistic, randomised, blinded, cross-over study

Lyhne MD, Liteplo AS, Zeleznik OA, Dudzinski DM, Andersen A, Shokoohi H, Al Jalbout N, Eke OF et al.

BMJ open, 2024

80 participants · 2 citations

Abstract

Background: Acute pulmonary embolism (PE) mortality is linked to abrupt rises in pulmonary artery (PA) pressure due to mechanical obstruction and pulmonary vasoconstriction, leading to right ventricular (RV) dilation, increased RV wall tension and oxygen demand, but compromised right coronary artery oxygen supply. Oxygen is a known pulmonary vasodilator, and in preclinical animal models of PE, supplemental oxygen reduces PA pressures and improves RV function. However, the mechanisms driving these interactions, especially in humans, remain poorly understood. The overall objective of the supplemental oxygen in pulmonary embolism (SO-PE) study is to investigate the mechanisms of supplemental oxygen in patients with acute PE.

Methods and analysis: This randomised, double-blind, cross-over trial at Massachusetts General Hospital will include adult patients with acute PE and evidence of RV dysfunction but without hypoxaemia (SaO2 ≥90% on room air). We will enrol 80 patients, each serving as their own control, with 40 randomised to start on supplemental oxygen, and 40 randomised to start on room air. Over 180 min, patients will alternate between supplemental oxygen delivered by non-rebreather mask (60% FiO2) and room air (21% FiO2). The primary outcome will be the difference in pulmonary artery systolic pressure with and without oxygen. Secondary outcomes include additional echocardiographic measures, metabolomic profiles, vital signs and dyspnoea scores. Echocardiographic data…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 80 participants or records.

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