The impact of an hematocrit of 20% during normothermic cardiopulmonary bypass for elective low risk coronary artery bypass graft surgery on oxygen delivery and clinical outcome--a randomized controlled study [ISRCTN35655335].
BACKGROUND
Cardiopulmonary bypass (CPB) induces hemodilutional anemia, which frequently requires the transfusion of blood products. The objective of this study was to evaluate oxygen delivery and consumption and clinical outcome in low risk patients who were allocated to an hematocrit (Hct) of 20% versus 25% during normothermic CPB for elective coronary artery bypass graft (CABG) surgery.


METHODS
This study was a prospective, randomized and controlled trial. Patients were subjected to normothermic CPB (35 to 36 degrees C) and were observed until discharge from the intensive care unit (ICU). Outcome measures were calculated whole body oxygen delivery, oxygen consumption and clinical outcome. A nonparametric multivariate analysis of variance for repeated measurements and small sample sizes was performed.


RESULTS
In a total of 54 patients (25% Hct, n = 28; 20% Hct, n = 26), calculated oxygen delivery (p = 0.11), oxygen consumption (p = 0.06) and blood lactate (p = 0.60) were not significantly different between groups. Clinical outcomes were not different between groups.


CONCLUSIONS
These data indicate that an Hct of 20% during normothermic CPB maintained calculated whole body oxygen delivery above a critical level after elective CABG surgery in low risk patients. The question of whether a transfusion trigger in excess of 20% Hct during normothermic CPB is still supported requires a larger prospective and randomized trial.
von Heymann
Christian
C
Department of Anesthesiology and Intensive Care Medicine, Charité-University Hospital Berlin, Charité Campus Mitte, Berlin, Germany. christian.von_heymann@charite.de
Sander
Michael
M
Foer
Achim
A
Heinemann
Anja
A
Spiess
Bruce
B
Braun
Jan
J
Krämer
Michael
M
Grosse
Joachim
J
Dohmen
Pascal
P
Dushe
Simon
S
Halle
Jürgen
J
Konertz
Wolfgang F
WF
Wernecke
Klaus-Dieter
KD
Spies
Claudia
C
D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis / Q000379:methods; D002315:Cardiopulmonary Bypass / Q000379:methods; D001026:Coronary Artery Bypass / Q000379:methods; D017558:Elective Surgical Procedures / Q000379:methods; D005260:Female; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010865:Pilot Projects; D011446:Prospective Studies; D012307:Risk Factors; D016896:Treatment Outcome