An analysis thread for the Jeff Thompson incident

[RN]

Jimmy Herbert, Jeff's dive partner during the week preceding the incident, has offered in this thread to provide details from his log book so we can analyze the incident a little better informed. So taking his cue, I've started this thread for that purpose. Hopefully this will help us learn from this incident and help us prevent something similar happening if it can be prevented.

[jimmy herbert]

I was Jeff’s buddy on all dive but those noted with an *, so our profiles over the week should be very similar. I was not diving with him on his last dive, therefore I can only offer second hand information.

Peacock

Dive 1 52’ max 94 min 32%/32% deco
Surface interval 2 hrs

Dive 2 65’ max 87 min 32%/32% deco
Surface interval 18.25 hrs

Dive 3 67’max 76 min 32%/32% deco
Surface interval 3 hrs

Dive 4 60’ max 84 min 32%/32% deco
Surface interval 19 hrs

Little River

Dive 5 104’ max 61 min 32%/100% deco
Surface interval 2.75 hrs

Dive 6 103’ max 66 min 32%/100% deco
Surface interval 19 hrs

Manatee

Dive 7 * 92’ max 71 min 32%/100% deco
Surface interval 2.75 hrs

Dive 8 * 91’ max 78 min 32%/100% deco
Surface interval 19 hrs

Madison

Dive 9 85’ max 71 min 32%/32% deco
Surface interval 2.25 hrs

Dive 10 70’ max 72 min 32%/32% deco
Surface interval 19 hrs

Ginnie

Dive 11* 88’ max 45 min 32%/32% deco


It should be noted that Jeff was not a smoker and drank no alcohol. He was well rested, well hydrated and well prepared for the dives.

All dives were executed exactly as planned, no surprises and zero stress. We all (6-8 divers) filled at the same location, at the same time. We all analyzed our gas with our own analyzers and compared results.

I think it’s worth mentioning that Jeff and I were both experiencing mild headaches. It wasn’t until the end of day two that I mentioned my headaches, and he confirmed that he too was having them. By the time we dove Madison, I no longer had any headache whatsoever, but Jeff still did. These were mild and diminished after a couple hours.

If there’s any other info that may be useful that I may have omitted, please let me know. If I have the info I’ll certainly share it.

[mgersch]

First, let me say I am very sorry for your loss, and thank you for your willingness to answer some questions to help find the cause.

1. So the fatal dive was dive 12 in the series? Do you have any info (2nd hand or otherwise) on the surface interval and profile of that dive?

2. So the partner that was with him on the last 2 dives...which of the other dives did he go on?

3. You mentioned you both had been having headaches, and also that you did not do dive 12. Did you not do dive 12 because you were not feeling well, or was it just a matter of having to head back ect....?

4 Had Jeff ever had an episode of bends or taken a chamber ride to your knowledge?

5. Had Jeff ever commented to you (in the past or that week) about any symptoms that might, only in retrospect, have been at least consistent with mild O2 symptoms such as tunnel vision, numbness, tingling, vertigo, dizziness ect...???

Hopefully, some good can come from this thread. Thanks again for your willingness to discuss this tragic event.
Sincerely,
-Mike Gersch

[FW]

I think it’s worth mentioning that Jeff and I were both experiencing mild headaches. It wasn’t until the end of day two that I mentioned my headaches, and he confirmed that he too was having them. By the time we dove Madison, I no longer had any headache whatsoever, but Jeff still did. These were mild and diminished after a couple hours.

If there’s any other info that may be useful that I may have omitted, please let me know. If I have the info I’ll certainly share it.

Did you get your gas analyzed, for CO, CO2, etc?

[jimmy herbert]

First, let me say I am very sorry for your loss, and thank you for your willingness to answer some questions to help find the cause.

1. So the fatal dive was dive 12 in the series? Do you have any info (2nd hand or otherwise) on the surface interval and profile of that dive?

2. So the partner that was with him on the last 2 dives...which of the other dives did he go on?

3. You mentioned you both had been having headaches, and also that you did not do dive 12. Did you not do dive 12 because you were not feeling well, or was it just a matter of having to head back ect....?

4 Had Jeff ever had an episode of bends or taken a chamber ride to your knowledge?

5. Had Jeff ever commented to you (in the past or that week) about any symptoms that might, only in retrospect, have been at least consistent with mild O2 symptoms such as tunnel vision, numbness, tingling, vertigo, dizziness ect...???

Hopefully, some good can come from this thread. Thanks again for your willingness to discuss this tragic event.
Sincerely,
-Mike Gersch

1. Jeff's incident happened during dive #11.

2. His buddy at the time had dove with the group on all dives but day 1 at Peacock as he was a day behind us in travel. The three of us dove together at Madison the day before.

4. not to the best of my knowledge.

5. He never mentioned anything to me, but I've since learned that he mentioned some symptoms (tingling in his lips and blurred vision) during deco on O2 after long, deep dives. Most of the lake diving I'd done with him he used 50% for deco.

Did you get your gas analyzed, for CO, CO2, etc?

No, I haven't gotten the unused gas analyzed yet.

[mgersch]

Did you get your gas analyzed, for CO, CO2, etc?

Really great idea.
Although, I don't think that either of these would explain the incident unfortuately.

CO2 in the gas would raise the PaCO2 in the blood some. THe normal PaCO2 in the blood is about 40mmHg. Acute elevations of PaCO2 generally causes somulence and can cause respiratory depression but , generally not seizures. There is a case report of a seizure after high CO2 levels in 1 patient, but I think that was likely related to other causes, chiefly hypoxia.

CO intoxication should be easily detectable on the autopsy by checking methemaglobin levels, especially in a non-smoker. I would imagine that was done, but I don't know.

[RN]

5. He never mentioned anything to me, but I've since learned that he mentioned some symptoms (tingling in his lips and blurred vision) during deco on O2 after long, deep dives. Most of the lake diving I'd done with him he used 50% for deco.

This is the first I've heard this and is interesting. Did he have any of these symptoms the week before the incident? Or was this on previous trips/dives?

[FW]

Did you get your gas analyzed, for CO, CO2, etc?

Really great idea.
Although, I don't think that either of these would explain the incident unfortuately.

I was thinking more about the headaches earlier in the week, than the last dive.

[jimmy herbert]

This is the first I've heard this and is interesting. Did he have any of these symptoms the week before the incident? Or was this on previous trips/dives?

Not that he mentioned to any of the group.

[DogDiver]

Did you get your gas analyzed, for CO, CO2, etc?

I would be very concerned about hydrocarbon contamination. This test can only be done at specific labs.

http://www.analox.net/site/content_video/HyperGas.mpg