Partitioning of exhaled NO in ventilated patients undergoing cardiac surgery.
The change in exhaled NO after cardio-pulmonary bypass remains controversial. The aims were to determine whether exhaled NO sources (alveolar or bronchial) are modified after bypass, and whether mechanical ventilation (MV) settings during bypass modify exhaled NO changes. Thirty-two patients were divided into three groups: without MV during bypass and positive end-expiratory pressure (PEEP) (n=12), dead space MV without PEEP (n=10) and dead space MV with PEEP (n=10). Alveolar NO concentration and bronchial NO flux were calculated before and 1h after surgery using a two-compartment model of NO exchange developed in spontaneous breathing patients. Whereas a significant decrease in bronchial NO was found after bypass in the two groups without PEEP during bypass, this decrease was not observed in patients with dead space ventilation with PEEP. Alveolar NO was not significantly modified whatever the ventilation settings. In conclusion, the impairment of bronchial NO seemed related to airway closure since dead space mechanical ventilation with PEEP prevented its decrease.
Tadié
Jean-Marc
JM
Université Paris Descartes, Paris, France.
Zegdi
Rachid
R
Trinquart
Ludovic
L
Kurdi
Okba
O
Journois
Didier
D
Latremouille
Christian
C
Diehl
Jean-Luc
JL
Louis
Bruno
B
Fagon
Jean-Yves
JY
Fabiani
Jean-Noël
JN
Delclaux
Christophe
C
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001980:Bronchi / Q000378:metabolism*; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D045853:Exhalation; D005260:Female; D006801:Humans; D055370:Lung Injury / Q000209:etiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D011175:Positive-Pressure Respiration / Q000379:methods; D011650:Pulmonary Alveoli / Q000378:metabolism*; D012121:Respiration, Artificial / Q000379:methods; D012126:Respiratory Dead Space
D015415:Biomarkers; D009569:Nitric Oxide