The apnea test for brain death determination: an alternative approach.
BACKGROUND
Problems associated with the standard apnea test relate to overshooting or undershooting the target PaCO2, potentially compromising the viability of organs for transplantation or invalidating the test.


METHODS
In 60 adult patients, the authors used an alternative method using exogenously administered CO2 and measurement of end-tidal CO2.


RESULTS
All patients achieved an adequate respiratory stimulus (mean increase in PaCO2 was 28+/-3 mmHg, postapnea test pH was 7.20+/-.02). There was a clinically insignificant reduction in arterial blood pressure during testing, but no other complications occurred. Multiple regression analysis demonstrated a correlation between the predicted PaCO2 (predicted from the end-tidal CO2) and measured PaCO2 (64+/-9 versus 67+/-9; r=.75169, p<0.0001).


CONCLUSIONS
Exogenously administered CO2 as an alternative method for the standard apnea test was a reliable and safe method, with minimal complications that offers several advantages over the standard method.
Sharpe
Michael D
MD
Department of Anesthesia and Perioperative Medicine, University of Western Ontario, London Health Sciences Centre-University Campus, London, Ontario, Canada. michael.sharpe@lhsc.on.ca
Young
G Bryan
GB
Harris
Chris
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D001049:Apnea; D001784:Blood Gas Analysis; D001926:Brain Death / Q000175:diagnosis*; D001944:Breath Tests; D002245:Carbon Dioxide / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D012119:Respiration; D012129:Respiratory Function Tests / Q000379:methods*
D002245:Carbon Dioxide