A single open sea air dive increases pulmonary artery pressure and reduces right ventricular function in professional divers
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After decompression from dives, bubbles are frequently observed in the right ventricular outflow tract and may lead to vascular damage, pulmonary arterial hypertension and right ventricular overload. No data exist on the effect of open sea diving on the pulmonary artery pressure (PAP). Eight professional divers performed an open sea air dive to 30 msw. Before and postdive a Doppler echocardiographic study was undertaken. Systolic pulmonary artery pressure (SPAP) was estimated from measurement of peak flow velocity of the tricuspid regurgitant jet; the ratio between pulmonary artery acceleration times (AccT) and right ventricular ejection time (RVET) was used as an estimate of the mean PAP. No evidence of either patent foramen ovale or intra-pulmonary shunt was found in any subject postdive after performing a Valsalva maneuver. SPAP increased from 25 ± 3 to 33 ± 2 mmHg and AccT/RVET ratio decreased from 0.44 ± 0.04 to 0.3 ± 0.02 20 min after the dive, respectively. Pulmonary vascular resistance increased from 1.2 ± 0.1 to 1.4 ± 0.1 Woods Units. Postdive right ventricle end-diastolic and end-systolic volumes were increased for about 19% (P = 0.001) and 33% (P = 0.001) and right ejection fraction decreased about for 6% (P = 0.001). Cardiac output decreased from 4.8 ± 0.9 (l min−1) to 4.0 ± 0.6 at 40 min postdive due to decreases in heart rate and stroke volume. This study shows that a single open sea dive may be associated with right heart overload due to increased pressure in the pulmonary artery.
KeywordsDiving Pulmonary artery pressure Professional Cardiac output Gas bubbles
This study was supported by the Croatian Ministry of Science, Education and Sports, Grant No. 216006 and by the Norwegian Petroleum Dierctorate, Norsk Hydro, Esso Norge and Statoil under the ‘Dive contingency contract no 4600002328’ with Norwegian Underwater Intervention. Authors would like to thank Aleksandra Mišak for the editing of the manuscript.
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