Comparing the Effects of Two Different Levels of Hyperoxygenation on Gas Exchange During Open Endotracheal...

Endotracheal suctioning is required for mechanically ventilated patients to maintain a patent airway. Studies show that open endotracheal suctioning affects respiratory mechanics and gas exchange. The aim of this study was to compare the effectiveness of hyperoxygenation with F_IO + 0.20 above baseline and hyperoxygenation with F_IO 1.0 in preventing hypoxemia, and to determine the impact of open endotracheal suctioning on the pulmonary ventilation of critical subjects receiving mechanical ventilatory support.

This prospective randomized crossover study was conducted in the ICU. Sixty-eight mechanically ventilated subjects with F_IO ≤ 0.6 and requiring endotracheal suctioning were included in this study. Open endotracheal suctioning was performed using 2 different intervention sequences: hyperoxygenation of 0.20 above baseline F_IO (F_IO + 0.20) and 1.0 hyperoxygenation (F_IO 1.0). Oxygenation was assessed via oxygen saturation as measured by pulse oximetry (S_pO ), and changes in lung ventilation were measured via alveolar gas volume (V̇_A), alveolar minute volume (V̇_{A min}), carbon dioxide (CO₂) production (V̇_CO ), mixed exhaled partial pressure of CO₂ (P_̄ECO ), exhaled tidal CO₂ volume (V_TCO₂), end-tidal CO₂ (P_ETCO ), anatomical dead space to tidal volume ratio (V_D/V_T), and anatomical dead space volume of each breath (V_D) using volumetric capnography, and breathing frequency (f), heart rate, and mean arterial pressure using a multiparameter monitor.

S_pO levels were significantly higher within interventions (F_IO + 0.20 and 1.0) 1 min before and after suction. Also, there was a significant increase in P_ETCO , P_̄ECO , heart rate, and mean arterial pressure immediately after the procedure compared with baseline, and in V_TCO₂, only for F_IO + 0.20. Baseline values were not found to be significantly different between the groups in case of any dependent variable.

In mechanically ventilated adult subjects, hyperoxygenation with F_IO + 0.20 above baseline prevents hypoxemia. Also, transient changes in pulmonary ventilation with open circuit suctioning were confirmed by volumetric capnography analysis. (Trial registration: ClinicalTrials.gov NCT02440919).