Changes in lung volume with three systems of endotracheal suctioning with and without pre-oxygenation in patients with mild-to-moderate lung failure

Objective: To compare changes in lung volume. oxygenation, airway pressure, and hemodynamic effects induced by suctioning with three systems in critically ill patients with mild-to-moderate lung disease, and also to evaluate the effects of hyperoxygenation applied prior to the maneuver as suggested by some guidelines. Design: Prospective crossover study. Setting: General intensive care department of a university-affiliated hospital. Patients: Ten mechanically ventilated patients with mild-to-moderate acute respiratory failure. Interventions: Patients were ventilated in volume control mode with a mean tidal volume of 490 88 ml, PEEP 7+/-4 cmH2O and FiO(2) 0.36+/-0.05. Suctioning was performed with a quasi-closed system, with an open system 10 min later, and finally with a closed system. Thereafter, pure oxygen was applied for 2 min and the whole suctioning sequence was repeated in reverse order. Measurements and main results: Patients' mean PaO2/FiO(2) ratio was 273+/-28 mmHg. The reductions in lung volume during suctioning were similar with the quasi-closed (386+/-124 ml) and closed system (497+/-338 ml), but significantly higher with the open system (1281+/-656 ml, P=0.022). We found no significant hemodynamic adverse effects, and no significant SpO(2) reductions with all the studied suctioning techniques. Pre-oxygenation with pure oxygen did not induce additive effects in lung volume changes. With and without pre-oxygenation, lung volume returned to baseline in every patient within 10 min. Conclusions: Suctioning with closed and quasi-closed systems reduces the substantial losses in lung volume observed with the open system. Nevertheless, in patients without severe lung disease these changes were transient and rapidly reversible.