The effect of leucodepletion on leucocyte activation, pulmonary inflammation and respiratory index in surgery for coronary revascularisation: a prospective randomised study.
OBJECTIVE
Leucocyte activation is central to end-organ damage that occurs during cardiac surgery under cardiopulmonary bypass (CPB). Exhaled nitric oxide (NO) increases in inflammatory lung conditions and has been proposed as a marker of pulmonary inflammation during CPB. This study examined the effect of leucodepletion on leucocyte activation, pulmonary inflammation and oxygenation in patients undergoing coronary revascularisation.


METHODS
Fifty low-risk patients undergoing first time coronary artery bypass graft (CABG) were randomised to two groups. Twenty-five patients had an arterial line leucocyte-depleting filter and 25 controls had a standard filter. Arterial blood samples were taken before CPB, 5 and 30 min on CPB, 5 min after aortic clamp removal and 6 h post-operatively. Activated leucocytes were identified with Nitroblue Tetrazolium staining. NO was sampled via an endotracheal teflon tube 15 min after median sternotomy before CPB and 30 min after discontinuation of CPB using a real-time chemiluminescense analyser. Respiratory index (alveolar-arterial oxygenation index, AaOI) was calculated before CPB, 1, 2, 4, 8 and 18 h post-operatively. Clinical outcome end-points were also recorded.


RESULTS
Total and activated leucocyte counts were significantly lower following leucodepletion during CPB (P < 0.0001). Exhaled NO rose significantly after CPB in the control group (3.8+/-1 ppb/s before CPB vs 5.6+/-2 ppb/s after CPB (P = 0.003) but not in the leucodepleted group (3.7+/-1 ppb/s before CPB vs 3.9+/-1 ppb/s after CPB (P = 0.051). AaOIs were consistently lower after leucodepletion (anova, P = 0.001). The duration of mechanical ventilation, the intensive care and hospital stay and the frequency of cardiac and respiratory complications were similar in the two groups.


CONCLUSIONS
Leucodepletion reduces the numbers of circulating activated leucocytes and the pulmonary inflammation during CPB. This appears to limit lung injury and improve oxygenation in low-risk patients undergoing CABG surgery. Larger numbers of patients are required to evaluate the effect of continuous arterial line leucodepletion on the clinical outcome.
Alexiou
Christos
C
Department of Cardiac Surgery, The General Hospital, Southampton, UK. alexiou486@aol.com
Tang
Augustine A T
AA
Sheppard
Stuart V
SV
Smith
David C
DC
Gibbs
Roz
R
Livesey
Steven A
SA
Monro
James L
JL
Haw
Marcus P
MP
D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000032:analysis; D002315:Cardiopulmonary Bypass; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology / Q000503:physiopathology; D007958:Leukocyte Count / Q000379:methods; D007962:Leukocytes / Q000502:physiology*; D008171:Lung Diseases / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization / Q000379:methods; D009569:Nitric Oxide / Q000032:analysis; D010100:Oxygen / Q000502:physiology; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D011650:Pulmonary Alveoli / Q000276:immunology* / Q000503:physiopathology; D013997:Time Factors
D015415:Biomarkers; D009569:Nitric Oxide; D010100:Oxygen