wow, very interesting suggestions! Thank you all very much. Unfortunately he couldn't wait for these suggestions and went to his absolute last resort remedy, olanzapine, the effects of which are like a temporary coma. He usually sleeps for 2 days after taking one of these and therefore it can cause serious disruption to his life. Will try the ice water if this happens again. Don O2: he uses a rebreather mask and had to crank the O2 up to a flow rate of 20 the other day, then it just stopped being effective altogether. Very scary.