Ventilation during cardiopulmonary bypass: impact on neutrophil activation and pulmonary sequestration.
BACKGROUND
Cardiopulmonary bypass (CPB) is associated with neutrophil activation, pulmonary sequestration, and release of inflammatory mediators leading to pulmonary dysfunction. We investigate the effect of continuous ventilation during cardiopulmonary bypass on neutrophil activation and pulmonary sequestration.


METHODS
Forty-six patients undergoing coronary artery bypass grafting with cardiopulmonary bypass were prospectively randomized to continuous ventilation and nonventilation groups. Blood samples were collected, and bronchoalveolar lavage (BAL) was performed following induction of anesthesia and at 4 hr after aortic declamping. Differential white cell count was measured, and flow cytometry to determine cell count numbers and quantify CD45 and CD11b leukocyte cell surface adhesion molecule expression was performed on the blood and BAL samples.


RESULTS
Twenty-three patients were randomized to standard nonventilated CPB and 23 patients to ventilation throughout CPB. Significant increases in blood and BAL neutrophil numbers were detected at 4 hr following aortic declamping in both groups (Blood: NV p < .0001, V p < .0001; BAL: NV p = .017, V p = .0007). No significant inter-group differences in BAL and blood neutrophil numbers were found. Significantly higher blood neutrophil CD11b mean fluorescent intensity levels were present 4 hr following declamping compared with baseline in both groups (NV Blood, p = .021; V Blood p < .0001). No significant inter- or intragroup differences in BAL neutrophil CD11b mean fluorescent intensity levels were found. There was no death or major complication.


CONCLUSIONS
Cardiopulmonary bypass during coronary artery bypass grafting is associated with increased neutrophil pulmonary sequestration, and blood neutrophil CD11b activation. Continuous ventilation during cardiopulmonary bypass does not significantly reduce neutrophil pulmonary sequestration or activation.
Division of Cardiothoracic Surgery, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong. calvinng@surgery.cuhk.edu.hk
Calvin S H
CS
Ng
Song
S
Wan
Innes Y P
IY
Wan
Connie W C
CW
Hui
Randolph H L
RH
Wong
Anthony M H
AM
Ho
Malcolm J
MJ
Underwood
D000368:Aged; D001998:Bronchopulmonary Sequestration / Q000150:complications / Q000517:prevention & control; D039481:CD11b Antigen / Q000502:physiology; D002315:Cardiopulmonary Bypass / Q000009:adverse effects / Q000379:methods*; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D007430:Intraoperative Care / Q000379:methods*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D018375:Neutrophil Activation; D009504:Neutrophils / Q000166:cytology; D012121:Respiration, Artificial / Q000379:methods*
D039481:CD11b Antigen; C509295:ITGAM protein, human