HEAfORRHAGIC SHOCK-OVKRTON and Dk BAKEY 



383 



80 r 



No survivors 

 No animals 



trol Cooling Chlorpromozine Chlorpromazine Chlorpromoz.ne Chlorjpromozme 



5mg. 5 mg 50 mg 50mg. 



+ Cooiing ♦Cooling 



P 05 P. 05 P .01 P.OOI P. 001 



Fig. 1. — Immediate survival in experimental hemorrhagic shock. 



larger doses. These results are valid statistically at P values of <.05 significance 

 level for cooling alone and for 5 mg. of chlorpromazine alone, <.01 for combined 

 cooling and 5 mg. dosage of chlorpromazine, and <.001 for 50 mg. dosage of 

 chlorpromazine either alone or combined with cooling. 



A protective mechanism is also suggested by the increased tolerance to duration 

 of hypotension, or duration of shock, before the 40 per cent end-point was reached. 

 Whereas in only 8 per cent of the control animals was the blood pressure maintained 

 at 30 mm. Hg for eight hours without having to retake 40 per cent of their maxi- 

 mum bleeding volume, among the treated animals this figure was significantly 

 greater. Particularly striking in this connection is the high proportion of "tolerance" 

 hypotension among those treated by the combined use of hypothermia and chlor- 

 promazine (fig. 3). At arbitrary completion at eight hours the control animals were 

 61.8 per cent short of the 40 per cent end-point, whereas the hypothermic dogs 

 were 40.3 per cent, the 5 mg. chlorpromazine-treated 17 per cent, the 50 mg. chlor- 

 promazine treated 79 per cent, the cooled and 5 mg. chlorpromazine-treated 72 

 per cent, and the cooled and 50 mg. chlorpromazine-treated were 80.3 per cent. 

 This may be considered a further reflection of compensation to hypotension without 

 necessity for replacement. 



Additional support of tolerance is manifested by the average duration of hypo- 

 tension, including the animals that were arbitrarily terminated at eight hours. The 



