Comparing the Effects of Two Different Levels of Hyperoxygenation on Gas Exchange During Open Endotracheal Suctioning: A Randomized Crossover Study

BACKGROUND: 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 2 + 0.20 above baseline and hyperoxygenation with F IO 2 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. METHODS: This prospective randomized crossover study was conducted in the ICU. Sixty-eight mechanically ventilated subjects with F IO 2 ≤ 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 2 (F IO 2 + 0.20) and 1.0 hyperoxygenation (F IO 2 1.0). Oxygenation was assessed via oxygen saturation as measured by pulse oximetry (S pO 2 ), and changes in lung ventilation were measured via alveolar gas volume (V̇ A ), alveolar minute volume (V̇ A min ), carbon dioxide (CO 2 ) production (V̇ CO 2 ), mixed exhaled partial pressure of CO 2 (P ̄ECO 2 ), exhaled tidal CO 2 volume (V T CO 2 ), end-tidal CO 2 (P ETCO 2 ), 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. RESULTS: S pO 2 levels were significantly higher within interventions (F IO 2 + 0.20 and 1.0) 1 min before and after suction. Also, there was a significant increase in P ETCO 2 , P ̄ECO 2 , heart rate, and mean arterial pressure immediately after the procedure compared with baseline, and in V T CO 2 , only for F IO 2 + 0.20. Baseline values were not found to be significantly different between the groups in case of any dependent variable. CONCLUSIONS: In mechanically ventilated adult subjects, hyperoxygenation with F IO 2 + 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).