Static Immersion and Negative Static Lung Load-Induced Right Ventricle Systolic Function Adaptation: A Risk Factor for Immersion Pulmonary Edema.

ABSTRACT

BACKGROUND: Immersion pulmonary edema (IPE) is a form of hemodynamic edema likely involving individual susceptibility. RESEARCH QUESTION Can assessing right ventricle (RV) systolic adaptation during immersion be a marker for IPE susceptibility? STUDY DESIGN AND METHODS: Twenty-eight divers participated 15 study participants with a history of IPE (IPE group; mean ± SD age, 40.2 ± 8.2 years; two women) and 13 control participants (no IPE group; mean ± SD age, 43.1 ± 8.5 years; two women) underwent three transthoracic echocardiography studies under three different conditions dry (participants were in the supine position on an examination table without immersion), surface immersion (participants were floating prone on the water's surface and breathing through a snorkel), and immersion and negative static lung load (divers were submerged 20 cm below the water's surface in the prone position using a specific snorkel connected to the surface for breathing). Echocardiographic measurements included tricuspid annular plane systolic excursion (TAPSE), tissue S' wave, and right ventricle global strain (RVGLS). RESULTS: For all divers, immersion increased RV preload. In the no IPE group, the increase in RV preload induced by immersion was accompanied by an improvement in the contractility of the RV, as evidenced by increases in TAPSE (17.08 ± 1.15 mm vs 20.89 ± 1.32 mm), S' wave (14.58 ± 2.91 cm/s vs. 16.26 ± 2.77 cm/s), and RVGLS (25.37 ± 2.79 % vs. 27.09 ± 2.89 %). Negative SLL amplified these RV adaptations. In contrast, among divers with IPE, the increase in RV preload did not coincide with an improvement in RV contractility, indicating altered adaptive responses. In the IPE group, the TAPSE values changed from 17.19 ± 1.28 mm to 21.69 ± 1.67 mm and then to 23.55 ± 0.78 mm, respectively, in the dry, surface immersion, and immersion and negative SLL conditions. The S' wave values changed from 13.42 ± 2.94 cm/s to 13.26 ± 2.96 cm/s and then to 12.49 ± 0.77 cm/s, respectively, and the RVGLS values changed from -24.09% ± 2.91% to -23.99% ± 3.38% and then to -21.96% ± 0.55%, respectively. INTERPRETATION: Changes in RV systolic function induced by immersion (especially with the addition of negative static lung load) vary among divers based on the history of IPE. Analyzing ventricular contractility during immersion, particularly RVGLS, could help to identify individual susceptibility in divers. These findings provide insights for the development of preventive strategies. TRIAL REGISTRY Comité de Protection des Personnes; No. 21.05.05.35821; Recherche Impliquant la Personne Humaine de type 1 (RIPH1) HPS; No. 2021-A01225-36.