 mean ph low temperatur extra-corpor circul review temperatur gradient occur profound hypothermia regard acid base chang gener ph read conclud term 'bodi' 'mean' 'averag' 'core' temperatur discard temperatur quot refer site measur main circumst blood ph measur temperatur blood equilibr respiratori gase review describ chang occur tonometri experi fundament chang understood consid complic sequenc event place live bodi alter occur concentr protein bicarbon ion blood cool review influenc 'correct factor' reason factor appli blood live bodi undergo hypothermia involv extra-corpor circul discuss exampl numer valu blood ph main method produc profound hypothermia autogen lung perfus pump-oxygen refer influenc pco2 valu exist method acid-base measur appear accur reflect metabol compon profound hypothermia 