Abstract
Introduction: Previous studies have suggested that the circulatory system was involved in the production of circulatory bubbles after diving. This study was designed to research the cardio-vascular function characteristics related to the production of high bubble grades after diving.Methods: Thirty trained divers were investigated both at baseline and after a 30-msw SCUBA dive. At baseline, the investigations included blood pressure measurement, echocardiography, and assessment of aerobic fitness using VO2 peak measurement. Blood samples were taken at rest, to measure the plasma concentration of NOx and endothelin-1. After diving, circulating bubbles were detected in the pulmonary artery by pulsed Doppler at 20-min intervals during the 90 min after surfacing. The global bubble quantity production was estimated by the KISS index.Results: Divers with a high bubble grade (KISS > 7.5) had systolic blood pressure, pulse pressure, weight, and height significantly higher than divers with a low bubble grade. By contrast, total arterial compliance, plasma NOx level, and percentage of predicted value of peak oxygen uptake were significantly lower in divers with a high bubble grade. Cardiac dimensions, left ventricular function, and plasma endothelin-1 concentration were not significantly different between groups. The multivariate analysis identified blood pressure as the main contributor of the quantity of bubble production. The model including pulse pressure, plasma NOx level, and percentage of predicted value of peak oxygen uptake has an explanatory power of 49.22%.Conclusion: The viscoelastic properties of the arterial tree appeared to be an important contributor to the circulating bubble production after a dive.
Highlights
MethodsThirty trained divers were investigated both at baseline and after a 30-msw SCUBA dive
Previous studies have suggested that the circulatory system was involved in the production of circulatory bubbles after diving
Total arterial compliance, plasma NOx level, and percentage of predicted value of peak oxygen uptake were significantly lower in divers with a high bubble grade
Summary
Thirty trained divers were investigated both at baseline and after a 30-msw SCUBA dive. The investigations included blood pressure measurement, echocardiography, and assessment of aerobic fitness using VO2 peak measurement. After diving, circulating bubbles were detected in the pulmonary artery by pulsed Doppler at 20-min intervals during the 90 min after surfacing. The subjects spent 3 min at rest to reach a steady-state gas exchange condition. Thereafter, all participants carried out a 4-min warm-up running session at 8 km h−1 with an elevation of 2%, after which the treadmill speed was increased by 1 km h−1 every 1 min until volitional fatigue was reached. The criteria indicating maximal exercise were as follows: plateauing of oxygen consumption, respiratory gas exchange ratio ≥1.1, and heart rate (HR) ≥95% age-predicted maximal HR. No diver was considered to be overweight, according to the formula: weight (kg) > 0.79 × height (cm) − 60.7
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