lamont
Contributor
I've seen it asked before if anyone has oxtox'd at less than 2.0 or 1.8 ppo2 and found a couple accounts yesterday, from http://www.iucrr.org/aa_misc.htm:
Pompano Beach, Florida USA
93OCT-A diver experienced what appeared to be the first onslaught of a CNS oxygen toxicity hit during an air dive to 228 fsw/70 msw on the RV Johnson, was able to make a rapid ascent to about 105 fsw/32 msw and survived. The diver and two others descended towards the wreck in order to set the anchor. Missing the wreck, and being deeper than they had planned, the divers began a hard swim at about 228 fsw/70 msw (PO2 = 1.66 atm) for about five minutes out of what was planned to be a 10 minute bottom time. He reached the mast at 190 fsw and tied off the anchor.
As he was working he got a severe pain in his molar, his lip began twitching and his jaw started chattering. Feeling a convulsion coming on, he held his regulator in his mouth, tried to signal to his partners and hit his BCD inflator just as he began to lose his vision and experience a mild convulsion. They symptoms began to clear during the rapid ascent and he was able to regain control about 115-120 fsw/35-37 msw and stopped himself at about 105 feet/32 meters. The diver was then able to pull himself together. He completed his scheduled decompression and included a 20 fsw/6 msw oxygen "hedge" stop on EAN 80 (80% O2, balance N2). He surfaced without incident. An extenuating factor may have been the prescription decongestant, Entex LA. The drug had been used by the diver at recommended doses during the preceding week of diving. He had previously bought a regulator retaining by "forgot" to bring it that day. According to the Divers Alert network (DAN) there is no data to link the drug to the incident.
Sydney, Australia
93AUG-A wreck diver lost consciousness during a 15 minute deep air dive to 78 msw/254 fsw on the paddle tug, Koputai, and drowned. The diver lost consciousness while returning to the anchor line after a 15 minute planned bottom time to make his ascent. Though his three partners attempted to ascend with the diver in tow, they were unable to maintain a regulator in his mouth and he subsequently drowned. The team preceded to lift the unconsciousness diver to 15 msw/50 fsw and released him to surface. Surface support personnel initiated EAR and radioed for emergency assistance/evacuation. The diver did not regain consciousness and was pronounced dead a short time later. Though the Coroners report has not been released, CNS toxicity (working PO2 = 1.85 atm) compounded by possible CO2 build-up and narcosis-characteristic of deep air dives-is suspected as the primary causal factor. The incident raised government concerns about local deep diving practices. Though mix training has just gotten started in Australia, most deep dives are still conducted on air.
-Submitted by Richard Taylor, Sydney, Australia.+
Pompano Beach, Florida USA
93OCT-A diver experienced what appeared to be the first onslaught of a CNS oxygen toxicity hit during an air dive to 228 fsw/70 msw on the RV Johnson, was able to make a rapid ascent to about 105 fsw/32 msw and survived. The diver and two others descended towards the wreck in order to set the anchor. Missing the wreck, and being deeper than they had planned, the divers began a hard swim at about 228 fsw/70 msw (PO2 = 1.66 atm) for about five minutes out of what was planned to be a 10 minute bottom time. He reached the mast at 190 fsw and tied off the anchor.
As he was working he got a severe pain in his molar, his lip began twitching and his jaw started chattering. Feeling a convulsion coming on, he held his regulator in his mouth, tried to signal to his partners and hit his BCD inflator just as he began to lose his vision and experience a mild convulsion. They symptoms began to clear during the rapid ascent and he was able to regain control about 115-120 fsw/35-37 msw and stopped himself at about 105 feet/32 meters. The diver was then able to pull himself together. He completed his scheduled decompression and included a 20 fsw/6 msw oxygen "hedge" stop on EAN 80 (80% O2, balance N2). He surfaced without incident. An extenuating factor may have been the prescription decongestant, Entex LA. The drug had been used by the diver at recommended doses during the preceding week of diving. He had previously bought a regulator retaining by "forgot" to bring it that day. According to the Divers Alert network (DAN) there is no data to link the drug to the incident.
Sydney, Australia
93AUG-A wreck diver lost consciousness during a 15 minute deep air dive to 78 msw/254 fsw on the paddle tug, Koputai, and drowned. The diver lost consciousness while returning to the anchor line after a 15 minute planned bottom time to make his ascent. Though his three partners attempted to ascend with the diver in tow, they were unable to maintain a regulator in his mouth and he subsequently drowned. The team preceded to lift the unconsciousness diver to 15 msw/50 fsw and released him to surface. Surface support personnel initiated EAR and radioed for emergency assistance/evacuation. The diver did not regain consciousness and was pronounced dead a short time later. Though the Coroners report has not been released, CNS toxicity (working PO2 = 1.85 atm) compounded by possible CO2 build-up and narcosis-characteristic of deep air dives-is suspected as the primary causal factor. The incident raised government concerns about local deep diving practices. Though mix training has just gotten started in Australia, most deep dives are still conducted on air.
-Submitted by Richard Taylor, Sydney, Australia.+