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-IO2 + 0.20 above baseline and hyperoxygenation with F-IO2 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-IO2 <= 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-IO2 (F-IO2 + 0.20) and 1.0 hyperoxygenation (F-IO2 1.0). Oxygenation was assessed via oxygen saturation as measured by pulse oximetry (S-pO2), and changes in lung ventilation were measured via alveolar gas volume ((V) over dot(A)), alveolar minute volume ((V) over dot(A) min), carbon dioxide (CO2) production ((V) over dot(CO2)), mixed exhaled partial pressure of CO2 (P-(E) over bar CO2), exhaled tidal CO2 volume (VTCO2), end-tidal CO2 (P-ETCO2), 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-pO2 levels were significantly higher within interventions (F-IO2 + 0.20 and 1.0) 1 min before and after suction. Also, there was a significant increase in P-ETCO2, P-ECO2, heart rate, and mean arterial pressure immediately after the procedure compared with baseline, and in VTCO2, only for F-IO2 + 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-IO2 + 0.20 above baseline prevents hypoxemia. Also, transient changes in pulmonary ventilation with open circuit suctioning were confirmed by volumetric capnography analysis.