Lung mucociliary clearance after anesthesia with spontaneous and controlled ventilation

Anesthesia and controlled ventilation for 2 h delays mucociliary clearance from the lung. To elucidate the contribution of controlled ventilation, mucociliary clearance was assessed by tantalum bronchography and serial chest roentgenograms in 6 dogs. After an induction dose of 25 mg of thiopental/kg of body weight, tantalum insufflation, and immediate recovery from anesthesia, 7 +/- 7 per cent of the tantalum remained in peripheral airways at 6 h. This was not significantly different from the 16 +/- 7 per cent remaining at 6 hours when the dogs had breathed humidified air spontaneously through an endotracheal tube during 2 hours of anesthesia with thiopental (total, 40 mg/kg of body weight). However, when ventilation was controlled during 2 h of anesthesia with 40 mg of thiopental/kg, with a tidal volume of 10 ml/kg or 30 ml/kg, and with a partially deflated endotracheal tube cuff, 43 +/- 11 per cent and 48 +/- 9 per cent of the tantalum, respectively, remained in peripheral airways at 6 h. We conclude that peripheral lung mucociliary clearance is delayed by mechanical ventilation through an endotracheal tube, even with an inspiratory air leak, independent of the tidal volume chosen.