Wouter Sterk

Doppler Bubble Grades After Diving and Relevance of Body Fat

BACKGROUND From the literature on venous gas embolism (VGE) and decompression sickness (DCS), it remains unclear whether body fat is a predisposing factor for VGE and DCS. Therefore, this study analyses body fat (range 16-44%) in relation to precordial VGE measured by Doppler bubble grades. Also examined is the effect of age (range 34-68 yr), body mass index (BMI; range 17-34 kg x m(-2)), and a model estimate of VO2(max) (maximal oxygen uptake; range 24-54 ml x kg(-1) x min(-1)). METHODS Bubble grades were determined in 43 recreational divers after an open sea air dive of 40 min to 20 m. Doppler bubble grade scores were transformed to the logarithm of the number of bubbles/cm2, logB, and the logarithm of the Kissman Integrated Severity Score (KISS) to allow numerical analysis. Statistical analyses were performed with Pearsons regular and partial correlations, and uni- and multivariate linear regressions. RESULTS For divers in their midlife (and older), the analyses indicate that neither body fat nor BMI stimulate bubble formation, since correlations were nonsignificant. In contrast, age and especially VO2(max) appeared to determine VGE. For these types of dives it was found that logB = -1.1 + 0.02 age - 0.04Vo2(max). CONCLUSION Based on these data we conclude that body fat and BMI seem less relevant for diving. We recommend that medical examinations pay more attention to VO2(max) and age, and that international dive institutions come to a consensus regarding VO2(max) criteria.