Posted by Kendall Raine on May 14, 2001 at 11:22:42:
In Reply to: ? for those using CW doppler post dives.... posted by Kelpfish on May 13, 2001 at 17:21:53:
1) "...IS it purely subjective?"
2) "...what useful information are you gathering?"
1) It is subjective. Attempts to use computers to interpret (grade) post dive Doppler results have proven less than productive because of the difficulty of distinguishing heart, valve and other sounds from the sounds produced by bubbles. We do take baseline reads pre-dive. Getting a good bubble signal off the subclavial site isn't hard. That's not true for precordial.
2) I guess the answer depends on what you mean by useful. To me, any technique better than simply waiting to become symptomatic is useful. What is the nature of the utility? The Doppler is useful for detecting vascular bubbles. Vascular bubbles are correlated with decompression stress. Certain dive/deco profiles generate different levels of decompression stress. As such, the Doppler may prove useful for investigating the degree to which different deco schedules and deco gass mixes correlate with increased stress. I say "may" since many variables can affect Doppler results besides the dive profile itself.
Bottom Line:
1) It's not perfect
2) It's better than nothing
3) Will the data I'm collecting be used to "prove" that certain deco schedules are "safe?" No.
4) Will I and those I dive with use the results to influence the schedules we use, gasses we use and types of dives we do? Yes.