<b>Comparison of Capnography and Arterial Blood Gases for Prediction of Early Extubation Patients Undergoing Coronary Artery Bypass Graft Surgery</b>

Background: Early extubation of the ICU after coronary artery bypass graft (CABG) surgery improves recovery and the length of stay. Capnography is a noninvasive device, which is applied to identify the appropriateness of extubation, but its predictability against arterial blood gases (ABG) is unclear. Methods: This study used 70 random postoperative CABG patients to be divided into Capnography (n=35) and ABG (n=35) groups. At baseline, trigger, extubation and post-extubation, demographics, comorbidities, ventilatory, arterial blood gas and hemodynamic parameters were recorded. Between-group comparisons were done using t -tests and chi -square tests with 95% confidence intervals (CI). To determine independent predictors of early extubation, logistic regression was used. Results: Mean time to extubation was significantly shorter in the Capnography group (180 ± 40 min) versus ABG group (230 ± 60 min; mean difference −50 min, 95% CI −76 to −24; p < 0.001). Early extubation occurred in 28/35 (80.0%) patients in the Capnography group versus 22/35 (62.9%) in the ABG group (p = 0.186). Capnography patients had lower PaCO₂ at extubation (41.2 ± 5.5 mmHg vs 44.8 ± 6.1 mmHg; mean difference −3.6 mmHg, 95% CI −6.4 to −0.8; p = 0.012) and higher pH (7.38 ± 0.04 vs 7.35 ± 0.05; mean difference 0.03, 95% CI 0.01–0.05; p = 0.007). They also experienced fewer alarms (1.8 ± 1.0 vs 3.1 ± 1.4; mean difference −1.3, 95% CI −1.9 to −0.7; p < 0.001), fewer manipulations (2.2 ± 1.1 vs 3.0 ± 1.5; mean difference −0.8, 95% CI −1.4 to −0.2; p = 0.013), and shorter ICU stay (2.1 ± 0.8 vs 2.8 ± 1.1 days; mean difference −0.7, 95% CI −1.1 to −0.3; p = 0.003). Logistic regression identified Capnography group (AOR 3.06; 95% CI 1.10–8.47; p = 0.031), normal PaCO₂ (AOR 2.67; 95% CI 1.01–7.02; p = 0.047), low alarms (AOR 3.18; 95% CI 1.21–8.29; p = 0.019), and short ICU stay (AOR 4.38; 95% CI 1.52–12.65; p = 0.006) as independent predictors of early extubation. Conclusion: Capnography is more effective than ABG in predicting early extubation after CABG surgery. It reduces time to extubation, improves ventilation parameters, minimizes alarms and manipulations, and is an independent predictor of successful early extubation