Determination of pump flow rate during cardiopulmonary bypass in obese patients avoiding hemodilution.
OBJECTIVE
During cardiopulmonary bypass the pump flow is usually set on 2.4 L/min/m(2) of body surface area (BSA) to guarantee adequate tissue perfusion without differences for patient constitutional type. The present study attempts to evaluate the adequacy of pump flow rate in obese patients, considering the ideal weight instead of the real one, avoiding the overflow side effects and hemodilution.


METHODS
Obese patients with body mass index (BMI) > 30 presented for cardiac surgery were randomized in two groups: in one the cardiopulmonary bypass was led traditionally, in the other, pump flow rate was calculated on ideal BMI of 25.


RESULTS
Demographics, preoperative tests, and monitoring data were registered. Mortality at hospital discharge and 30 days after were analyzed. The pump flow rate between the groups was different (4.46 vs. 4.87; p = 0.004); there were no differences in organ perfusion (SvO(2); diuresis) and mortality, but the study group presented fewer complications and blood transfusions.


CONCLUSIONS
The BSA is widely used as the biometric unit to normalize physiologic parameters included pump flow rate, but it is disputable if this practice is correct also in obese patients. The study group, in which pump flow rate was set on ideal BSA, presented no difference in diuresis and mixed venous saturation but fewer complications and fewer perioperative blood transfusions.
Department of Cardiac Surgery, Civil Hospital, Via Candiani 2, 20025, Legnano, Italy. salamina2003@libero.it
Luisa
L
Santambrogio
Cristian
C
Leva
Giorgio
G
Musazzi
Piergiorgio
P
Bruno
Andrea
A
Vailati
Franco
F
Zecchillo
Germano
G
Di Credico
D015992:Body Mass Index; D002315:Cardiopulmonary Bypass / Q000295:instrumentation*; D000075202:Contraindications; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006331:Heart Diseases / Q000150:complications / Q000378:metabolism / Q000601:surgery*; D006355:Heart-Lung Machine; D006438:Hemodilution; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology*; D012189:Retrospective Studies; D016896:Treatment Outcome