COPD Patients on Angiotensin Converting Enzyme Inhibitors undergoing Cardiopulmonary Bypass are More Likely to be Extubated within 24h

Long term treatment with ACEIs in COPD patients may be associated with shorter times to extubation. In specific populations, an association has also been reported with enhanced recovery from pneumonia and ARDS in COPD patients.

To test for a possible relationship between COPD and ACEIs, we conducted a retrospective analysis of 1992 CT surgery patients at a tertiary care hospital.

Interactions between COPD, smoking, and extubation by 24h were assessed using predicted probability and multivariate logistic regression. Models were examined for fit with ROC curves, and Sensitivity / Specificity tables.

Tables 1 a, b, and c illustrate the relationships of predictor variables across ACEI, COPD and smoking history. In Table 2a, for COPD patients that were not extubated, 6% were on ACEIs, and 29% were not (p=0.001). Three-way interactions in table 2b yielded a p-value of 0.01 for COPD non-smokers; In this category, 100% of patients taking ACEI were extubated successfully. In non-COPD patients who were smokers, the χ² p value was 0.08, but in COPD / Smokers, 9% of those on ACEIs were not extubated vs. 28% not on ACEI (p=0.04). Figure 2 illustrates predicted probabilities and Figure 3 lists a multivariate model. Across the continuous predictors, COPD patients on ACEI consistently demonstrate a higher overall probability of extubation by 24h. ARB’s did not demonstrate this relationship, and there was no effect with off pump CABG cases.

In our sample, COPD patients undergoing CPB who were taking ACEI, were associated with a higher probability of successful extubation by 24h.