Saturday, May 27, 2006

Hemodynamic Changes Induced by Recreational Scuba Diving

Dr. Howard Homler writes to let us know about an interesting article that he found in the Journal "Chest" concerning Hemodynamic Changes Induced by Recreational Scuba Diving* by Boussuges, Blanc and Carturan. The entire article cannot be seen without a subscription to the Journal or purchasing the material so we have published the abstract given below - since it is public record on Medline. The article pretty much supports what is already known about the cardiovascular effects of immersion, nitrogen saturation and bubbles upon decompression.

(Chest. 2006;129:1337-1343.)
© 2006 American College of Chest Physicians

Alain Boussuges, MD, PhD; François Blanc, PhD and Daniel Carturan, PhD

* From Institut de Médecine Navale du Service de Santé des Armées (Dr. Boussuges), Toulon Armées; and Université de la Méditerranée (Drs. Blanc and Carturan), Laboratoire de Physiopathologie et Action Thérapeutique des Gaz sous Pression, Faculté de Médecine Nord, Marseille, France.

Correspondence to: Alain Boussuges, MD, PhD, IMNSSA, B.P.610, 83800 Toulon; Toulon Armées, France; e-mail: alainboussuges@libertysurf.fr

Abstract

Objective: Cardiac changes induced by scuba diving were investigated using Doppler echocardiography.

Material and methods: Ten healthy scuba divers dove to a mean depth of 34.3 ± 2.7 m of sea water (113 ± 9 feet) and a mean duration of 25.3 ± 3.5 min.

Results: One hour after the dive, microbubbles could be detected in the right-heart chambers of all subjects. Left atrial and left ventricular (LV) diameters significantly decreased after the dive. Cardiac output, assessed by aortic blood flow, remained unchanged. Heart rate increased and stroke volume (SV) decreased after the dive. LV filling was assessed on transmitral profile. An increase of the contribution of the atrial contraction to LV filling was observed. Right cavity diameters were unchanged, but an increase of the right ventricular/right atrial gradient pressure was found.

Conclusion: The diving profile studied promotes a rather important bubble grade in all volunteers. A significantly reduced cardiac diameters and SV was found by our hemodynamic study 1 h after diving. Two factors can explain these results: low volemia secondary to immersion, and venous gas embolism induced by nitrogen desaturation. Consequently, restoration of the water balance of the body should be considered in the recovery process after diving.

Key Words: cardiac function • decompression • diving • Doppler • immersion • ultrasonography
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