Abstract
Inert gas bubbles frequently occur in SCUBA divers’ vascular systems, eventually leading
to decompression accidents. Only in professional settings, dive profiles can be adjusted
on individual basis depending on bubble grades detected through ultrasonography. A
total of 342 open-circuit air dives following sports diving profiles were assessed
using echocardiography. Subsequently, (Eftedal-Brubakk) bubble grades were correlated
with dive and individual parameters. Post-dive cardiac bubbles were observed in 47%
of all dives and bubble grades were significantly correlated with depth (r=0.46),
air consumption (r=0.41), age (r=0.25), dive time (r=0.23), decompression diving (r=0.19),
surface time (r=− 0.12). Eftedal-Brubakk categorical bubble grades for sports diving
with compressed air can be approximated by bubble grade = (age*50−1 – surface time*150−1+maximum depth*45−1+air consumption*4500−1)2 (units in years, hours, meter, and bar*liter; R2=0.31). Thus, simple dive and individual parameters allow reasonable estimation of
especially relevant medium to higher bubble grades for information on relevant decompression
stress after ascent. Echo bubble grade 0 is overestimated by the formula derived.
However, echo might fail to detect minor bubbling only. The categorical prediction
of individual decompression stress with simple bio and dive data should be evaluated
further to be developed towards dive computer included automatic ex-post information
for decision-making on individual safety measures.
Key words
decompression - bubble grade - SCUBA diving - Doppler ultrasound - risk management
