DEPT. OF ANESTHESIOLOGY AND INTENSIVE CARE AND ANESTHESIOLOGY RESEARCH CENTER, SHAHID BEHESHTI UNIVERSITY, M.C. TEHRAN, IRAN
Introduction: Cardiopulmonary bypass (CPB) in patients undergoing coronary artery bypass graft surgery (CABG) carries a number of drawbacks, namely its inflammatory effects on the lung parenchyma due to both the mechanical and inflammatory effects of the bypass circuit. The arterial oxygenation status is a marker that can demonstrate the alveolar performance and the possible detrimental effects on the lung tissue. This study was designed and executed to assess the effects of CPB on the lung oxygenation status.
Methods: In a before-after study, 370 cases among a population of 2000 patients undergoing elective CABG were studied. All the patients were compared with themselves in such a way that there was no need to match them before and after the exposure to the bypass circuit. The partial pressure of arterial oxygen before and after the operation and also the saturation of the oxygen in the arterial blood were checked before and after the operation on the final postoperative day of ICU stay. The Chi-square and non-parametric tests were used for data analysis. A P-value less than 0.05 was considered significant. SPSS software (version 11.5) was used for data analysis.
Results: Among the factors assessed, pump time and age had statistically significant effects on the oxygenation status of the patients undergoing CABG with bypass. Other variables, including the number of the grafts and ejection fraction before the operation were effective, but their effect was not statistically significant.
Discussion: A decreased pump time, especially in the elderly cases and those with an underlying disease, is highly recommended. Further studies regarding other respiratory markers including pulmonary function tests are recommended.