Age > 65, broad spectrum antibiotics, female sex, duration of mechanical ventilation, and a high acute physiology and APACHE II have all been related to the development of NP post CABG. Yet, none of these investigations has examined the reasons for the increased risk of NP post cardiac surgery in the elderly. The purpose of this study is to identify modifiable risk factors of nosocomial pneumonia (NP) in elderly patients post cardiac surgery.
We conducted a case-control study in a postoperative intensive care unit of a University affiliated hospital.Seventy three case-control pairs were identified. Controls subjects were matched for age, gender, type of surgery, forced expiratory volume in one second (FEV1), and ejection fraction.Baseline sociodemograpahic information, Charlson Comorbidity Index, intra-and postoperative data were collected. When suspected, the presence of NP was confirmed by quantitative culture of protected bronchoalveolar lavage fluid ≥103 colony forming unit/ml or positive blood/pleural fluid culture identical to that recovered from respiratory samples.
The incidence of NP in elderly post heart surgery was 8.3%. The mean duration after heart surgery to the occurrence of pneumonia was 7.2+/- 4.9 days. Four variables were found to be significantly related to the development of NP by multivariate analysis: Charlson Index > 2 (adjusted odds ratio [AOR] 4.7; 95% confidence interval [CI], 1.9-11.4; p < 0.001), reintubation (AOR 6.2; 95% CI, 1.1-36.1; p=0.04), transfusion ≥ 4 units of PRBC (AOR 2.8; 95% CI, 1.2-6.3; p=0.01), and the mean equivalent daily dose of morphine (AOR 4.6; 95% CI, 1.4-14.6; p=0.01).
This study has identified three potentially modifiable risk factors that are responsible for the occurrence of NP in the elderly population post cardiac surgery: reintubation, PRBC transfusion, and excessive use of narcotics.
Although there are limited effective measures to lessen the burden of comorbidities, avoiding reintubation, finding a substitute to allogenic blood transfusion, and improved assessment of pain management could reduce the rate of NP in the post operative period of cardiac surgery in the elderly population.
Ali El Solh, None.