End-tidal-to-arterial PCO2 ratio as a prognostic value in mechanically ventilated patients at respiratory intensive care unit

Abstract

Background Dead space refers to the part of each tidal volume that does not contribute to gas exchange. It serves as an indicator of lung function efficiency. Aim To evaluate the end-tidal-to-arterial PCO2 ratio and Acute Physiological and Chronic Health Assessment (APACHE IV) scoring system as prognostic values in mechanically ventilated patients at the respiratory intensive care unit (ICU). Patients and methods This prospective cohort research was done on 40 mechanically ventilated patients due to different respiratory causes who were admitted at the respiratory ICU at Ain Shams University hospitals. Results This study found that decreasing end tidal PCO2 (PETCO2)/arterial carbon dioxide (PaCO2) is associated with higher mortality amongst mechanically ventilated cases in respiratory ICU. A significant negative association between APACHE IV score and end-tidal to arterial PCO2 ratio following 1 h and after 24 h of mechanical ventilation. APACHE IV score showed a significant relation with mortality, being higher in survivors than nonsurvivors. Conclusion PETCO2/PaCO2 is a relevant prognostic value that reflects dead space ventilation among mechanically ventilated patients in respiratory ICU. APACHE IV score is a good mortality predictor in respiratory ICU.