Objective: To evaluate the ability of central venous-to-arterial carbon dioxide pressure difference, to detect extubation failure in critically ill patients.
Study design: Prospective observational study
Materials and methods: 64 critically ill patients who received mechanical ventilation for more than 48 hours and passed spontaneous breath trials (SBT) with pressure support ventilation for 60 minutes were enrolled for the study. Arterial blood gas and central venous blood gas analysis was performed immediately before SBT and 60 minutes after SBT and venoarterial carbon dioxide pressure difference (ΔPCO2) was calculated. Extubation was performed after successful SBT. Extubation failure was defined as reintubation within 48 hours of extubation.
Results: Extubation failure was noted in 16 patients. ΔPCO2 value increased in the extubation failure group and decreased in the success group (p <0.001). Changes in ΔPCO2 (Δ – ΔPCO2) during spontaneous breathing trials was independently associated with extubation failure (p <0.001). The mean number of ICU days was greater in the failure group [6.96±2.82] compared to the success group [5.00±1.22] (p=0.009). The average number of days spent on a ventilator was considerably more in the failure group [3.98±2.24] compared to the success group [3.01±1.14] (p=0.025).
Conclusion: We found that ΔPCO2 and Δ – ΔPCO2 during spontaneous breathing trials, were good predictors of weaning outcomes and they can be used to predict extubation failure and thereby reduce extubation failure rate.