Monitoring of brain oxygenation during hypothermic CPR - A prospective porcine study.
Limited data are available concerning the impact of CPR interventions on cerebral oxygenation during hypothermic cardiac arrest. We therefore studied cerebral perfusion pressure (CPP), brain tissue oxygen tension (PbtO2), cerebral venous oxygen saturation (ScvO2) and regional cerebral oxygen saturation (rSO2) in an animal model of hypothermic CPR. We also assessed the correlation between rSO2 and CPP, PbtO2 and ScvO2 to clarify whether near-infrared spectroscopy (NIRS) may be used to non-invasively monitor changes in cerebral oxygenation during hypothermic CPR.



Nine pigs were surface-cooled to a core temperature of 28°C and underwent a period of asphyxia before cardiac arrest was induced. After 2min of untreated cardiac arrest they were resuscitated for 45min. CPP, PbtO2, ScvO2 and rSO2 were monitored after periods of stable external chest compression, a short interruption of CPR and after epinephrine administration.



During external chest-compressions before adrenalin administration CPP, PbtO2, ScvO2 and rSO2 increased in parallel and changes in rSO2 closely correlated with changes in CPP (r=.844; p<.001) and ScvO2 (r=.868; p<.001). After adrenaline administration CPP and PbtO2 increased, ScvO2 decreased and rSO2 values did not change and there was no significant correlation between rSO2 and CPP, PbtO2, or ScvO2.



In this animal model of hypothermic cardiac arrest adrenaline was associated with an increase in global cerebral oxygen extraction despite an increase in CPP. Discrepancies in the time course of PbtO2 and ScvO2 suggest differences in regional oxygen metabolism after adrenalin. rSO2 values correlated closely with CPP and ScvO2 only during periods of external chest compression without adrenaline administration.
Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria. Electronic address: gabriel.putzer@i-med.ac.at.
Gabriel
G
Putzer
Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria.
Patrick
P
Braun
Institute of Mountain Emergency Medicine at the European Academy, Bolzano, Italy.
Giacomo
G
Strapazzon
Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria.
Martha
M
Toferer
Department of Neurosurgery, Medical University of Innsbruck, Austria.
Miriam
M
Mulino
Department of Radiology, Medical University of Innsbruck, Austria.
Bernhard
B
Glodny
Inova Q GmbH, Brunico, Italy.
Markus
M
Falk
Institute of Mountain Emergency Medicine at the European Academy, Bolzano, Italy.
Hermann
H
Brugger
Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria; St Bartholomew's Hospital, Bart Health NHS, Queen Mary University of London, United Kingdom.
Peter
P
Paal
Department of Neurology, Medical University of Innsbruck, Austria.
Raimund
R
Helbok
Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria.
Peter
P
Mair
D000818:Animals; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D016887:Cardiopulmonary Resuscitation; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D004837:Epinephrine / Q000494:pharmacology; D006323:Heart Arrest / Q000378:metabolism* / Q000503:physiopathology; D007036:Hypothermia, Induced; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D011446:Prospective Studies; D012121:Respiration, Artificial; D013552:Swine
D002245:Carbon Dioxide; D010100:Oxygen; D004837:Epinephrine
Brain/metabolism; Cardiac arrest; Cardiopulmonary resuscitation; Epinephrine; Hypothermia; Near-infrared spectroscopy