CHAPTER 14 Surface Supplied Mixed Gas Diving Procedures
Change A 14-13
presented here. Topside supervisory personnel must take whatever action they
deem necessary to bring the casualty under control.
Follow these procedures when the diver is convulsing at the 90-60 fsw water
Shift both divers to air if this action has not already been taken.
Have the unaffected diver ventilate himself and then ventilate the stricken
If only one diver is in the water, launch the standby diver immediately and
have him ventilate the stricken diver.
Hold the divers at depth until the tonic-clonic phase of the convulsion has sub-
sided. The tonic-clonic phase of a convulsion generally lasts 1 to 2 minutes.
At the end of the tonic-clonic phase, have the dive partner or standby diver
ascertain whether the diver is breathing. The presence or absence of breath
sounds will also be audible over the intercom.
If the diver appears not to be breathing, have the dive partner or standby diver
attempt to reposition the head to open the airway. Airway obstruction will be
the most common reason why an unconscious diver fails to breathe.
If the affected diver is breathing, have the dive partner or standby diver tend
the stricken diver and decompress both divers on air following the original
schedule. Shift the divers to 50% helium 50% oxygen upon arrival at 50 fsw.
Surface decompress upon completion of the 40 fsw water stop.
If it is not possible to verify that the affected diver is breathing, leave the unaf-
fected diver at the stop to complete decompression, and surface the affected
diver and the standby diver at 30 fsw/min. Shift the unaffected diver back to
his 50/50 mixture for completion of decompression. The standby diver should
maintain an open airway on the stricken diver during ascent. On the surface
the affected diver should receive any necessary airway support and be imme-
diately recompressed and treated for arterial gas embolism and missed
decompression in accordance with Table 21-5 and Figure 21-5.
CNS Oxygen Toxicity Systems (Nonconvulsive) at 30 and 20 fsw Water Stops.
If the diver develops symptoms of CNS oxygen toxicity at the 30 or 20 fsw water
stops, take the following action:
Shift the console to air and initiate surface decompression.
If surface decompression is not feasible, ventilate both divers with air and
complete decompression in the water on air. Compute the remaining stop