230 PHYSIOLOGY OF INDUCED HYPOTHERMIA 



TABLE I 



Effect of Hypothermia on Livp:r Respiration 



Oxygen consuniiition Carbon dioxide production 



ml./hr./lOOgm. _ ml./hr./lOO gni. 



Time after perfusion started, hrs. 



Temperature 1234 1234 



37° C 162± 4 140±11 133±9 131±10 111±8 n3±8 120±10 110±8 



24° C 68±10 63± 7 55±7 47± 8 59±7 54±0 44± 2 39±3 



All values + standard deviation of the mean. 



TABLE II 

 Effect of Hypothermia on the RQ of the Isolated Perfused Liver 



Time after perfusion started, hrs. 



Temperature 1 



37° C 0.70±.04 



24° C 0.85 + .09'' 



All values + standard deviation of mean. 



a P< 0.025 when compared to 1 hr. RQ at 37° C. 



the result of the demand for energy at 37° C. heing greater than that at 24° C. and 

 consequently the liver, heing unable to metabolize carbohydrate efficiently, burns 

 fat in an attempt to supply the necessary calories. However, at 24° C. the liver is 

 capable of meeting the limited energy demands by oxidizing an amount of glucose 

 sufficient for its needs. Apparently the liver is soon capable of utilizing the avail- 

 able carbohydrate more efficiently and in the second hour of perfusion at 37° C, 

 the RQ returns to normal. 



There is a marked efifect of hypothermia as well as that of l)arl)iturate on the 

 ability of liver to detoxify morphine. The biologic half-life for the loss of free 

 morphine from the plasma at 37" C. is 3.7 minutes; 94 minutes at 24° C. ; in the 

 presence of pentothal at 37° C, 14.7 minutes. Table III summarizes these figures 

 and, in addition, gives the biologic half-life of thiopental. 



Figure 3 illustrates the effect of hypothermia on morphine conjugation. Figure 4 

 is the portion of the curve from 1-2 hours and shows that following the injection ot 

 morphine at 24° C, the maximum value of free morphine is not reached for ap- 

 proximately 12 minutes and falls off quite slowly. Figure 5 is that portion of the 

 figure from 5-6 hours and shows that following the injection of morphine at 37° C, 

 the maximum concentration in the perfusion fluid is reached in 3 minutes and falls 



TABLE III 

 Effect of Hypothermia on Drug Detoxification by Liver 



No. of Exp. Half-Life (Minutes) 



37° C. 24° C. 37° C. 24° C. 



Morphine 8 4 3.7 94" 



Morphine ( witli pciitdtlial ) 4 — 14.7" — 



Pentothal 5 2 46 530 



185 



" P<0.05 when compared to morphine alone. 



'' P< 0.001 when compared to morphine at 37° C. 



