Wierd Scenario

diverrob

Thought I would share this interesting scenario I was involved with this week. Once a week we give Pressure Tolerance Tests (PTT) to candidates who want to become divers, this test required us to pressurize them to 99FSW for a bottom time of usually less than 10min.This week we had two candidates show up at the chamber for such test and we proceeded to administer the PTT. I must first explain that all of the candidates who show up must have first gone through a complete Diving Medical, physical test as well as a dental check. The PTT went as planned and all divers were on the surface :9::36min after they left surface. After exiting the chamber one of the candidates complained of blurry/double vision. The dive supervisor quickly sat him down and further investigated his symptoms. He started to deteriorate quickly and within a few min the decision was made to recompress to 60FSW on O2 and conduct a trial of pressure. By this time the patient was having trouble speaking and had severe weakness in his legs. Upon arrival at 60FSW on 100% O2 all of his symptoms had been resolved and he was feeling good. At this time we decided to treat him on a Treatment Table 6 (TT6). The treatment was completed without any reoccurrence of any symptoms and after the treatment was examined by an Advanced Diving Medical Doctor (ADMO) and was found well enough to be released but was told to stay with someone for the night. During the night he was woken up with an extreme head ache and feeling nauseated, he vomited a few times and finally told his friend who took him to the hospital and then to the chamber where we did another TT6. He exited the chamber feeling well and the ADMO had arranged for a CT scan at the local hospital. The scan reveled that the member had suffered a stroke and that he had damage to the right side of his brain but had no signs or symptoms of having a stroke. He was released form the hospital the next day. I am curious as to why he does not have any deficiencies from the stroke? Would it be because we treated him so quickly after the first symptoms showed? He is a young fit individual who does not fit the usual parameters for a stroke and yet the CT scan and the doctors say he had suffered one. Could the PTT be a catalyst for a stroke? I don’t know the answers so I thought I would see if any of you may. I can’t give out any specifics about him as that is confidential so I have kept things as general as possible. Let me know if you have any thoughts on this



Rob

ScubaDadMiami

I am not a doctor, and I don't play one on TV. However, I have always had an interest in this subject. So, from a non-expert perspective . . .

I some places (my understanding is that this is the case in places in Europe), they actually keep chambers in ambulances for stroke victims, taking them to the hospital under pressure while administering oxygen. This is done to keep more cells from damage due to lack of oxygen delivery during the stroke episode.

Beyond the immediate area of the stroke, cells around the site can be rendered to a sort of no-man's-land condition, where they are not dead but not functioning from the initial trauma. If deprived of blood flow and oxygen for long enough, they can die. However, if given sufficient oxygen, they can recover from this dormant state, lessening the damage from the stroke and causing improvement in the patient once the cells awaken and resume a more normal function. This is the reason for using hyperbaric treatment for stroke victims.

This being said, it is possible that your subject suffered a stroke in a location that did not cause a significant deficit in the first place. It is also possible that there would have been more serious effects had the subject not received immediate hyperbaric oxygen. It's anyone's guess.

As to the cause of the stroke being related to the pressurization, that goes beyond my limited knowledge. This almost sounds like a classic emolism type of event.

__________________
Howard Packer
IANTD CCR Instructor
Miami Beach, Florida
CCRDiveTraining.com

diverrob

I agree with you on the "classic embolism" My initial reaction was a bubble in the brain because of the symptoms and how fast they set in. Still it is a strange case and one I would like to follow up on.

babar

I think you're probobly right about the location. In general once they show on the ct scan they're there for good.

It sounds like he failed the test.

__________________
Babar
Evolution Plus
Sport kiss

Sutty

Sounds like cerebral arterial gas embolus. It would be interesting to have a CT lung to look for bullae. I presume there were no problems on ascent?

Obviously the individual shouldn't dive.

Neil

__________________
Never forget that life is a finite resource.

diverrob

No problem on assent was reported and I think he will probably have a complete medical work up in the coming weeks.

Rob

Simon Mitchell

Right on the money.

Unless this was a stunning coincidence, the chest x-ray (or CT even better) will likely be revealing. As Sutty suggests, I would expect to see a lesion that would predispose to pulmonary barotrauma.

The history of a quick and complete response to recompression is also strongly supportive of this event being related to CAGE during ascent from the initial "pressure test".

Scubadad,

The use of hyperbaric oxygen in treatment of "stroke" that is not caused by bubbles is much more controversial than portrayed. Indeed, stroke is not on the list of accepted indications for HBO published by the UHMS because at present there is no good evidence that it works. While it makes some sense that administration of HBO might help arrest the course of an evolving stroke, it has not been demonstrated convincingly in practice. Theories about "idling neurones' being resurrected by HBO are often repeated by those who make money from such treatments, but there is no proof that it actually happens. It is a space to watch, but at this stage its a bit disappointing. The response to HBO reported in the above case would be unusual in a stroke caused by thrombosis or a solid embolus.

Warm regards,

Simon M