Doppler-echocardiography study of cardiac function during a 36 atm (3,650 kPa) human dive
Lafay, V.; Boussuges, A.; Ambrosi, P.; Barthelemy, P.; Frances, Y.; Gardette, B.; Jammes, Y.
Undersea and Hyperbaric Medicine Journal of the Undersea and Hyperbaric Medical Society Inc 24(2): 67-71
1997
ISSN/ISBN: 1066-2936 PMID: 9171465 Document Number: 473565
To determine the influence of a saturation dive on cardiac function, Doppler-echocardiographic measurements were compared at sea level and during a 36 atm (3,650 kPa) He-O-2 dive (gas density: 7 g/liter) in four healthy men. Left ventricular systolic function was studied from time-motion measurements. Transmitral flow (E:A ratio) and isovolumetric relaxation time were used to assess left ventricular diastolic function. Cardiac output was derived from systolic pulmonary and aortic valvular flows. Cardiac output decreased 4.4 +- 0.8 vs. 5.9 +- 1.2 liter/min at sea level) whereas stroke volume, left ventricular ejection fraction, atria and ventricular diameters remained unchanged. Thus, the decrease in cardiac output was attributed to bradycardia (56 +- 8 vs. 73 +- 9 beats/min at sea level) which probably resulted from the slight hyperoxia (PI-O-2 0.4 atm). We found no evidence of left ventricular diastolic dysfunction. nor did we find valvular regurgitation or pulmonary hypertension. We conclude that Doppler-echocardiography can be used safety to investigate cardiac function during human saturation dives. Our results suggest that a 36 atm He-O-2 dive does not modify cardiac or systolic and diastolic function except for a slight decrease in cardiac output correlated to bradycardia.