Objectives: To evaluate both efficacy and safety parameters for insufflation through the bronchoscope as a method of recovery from sedation-induced hypoxia. To explore parameters applicable to use in human beings using an animal model.
Materials and methods: Two adult pigs were sedated enough to depress respiratory drive. The effects of insufflation at 15 l/min (the upper limits of flow that might be used clinically) were then evaluated. Pressure and volume responses to bronchoscopy during intubation and without an endotracheal tube in place were recorded. Several assays were performed for each scenario, with each animal acting as its own control. Recovery from hypoxemia using insufflation was compared with recovery using mechanical ventilation.
Results: Insufflation was effective, with rapid increases in fraction of inspired oxygen (FIO2), saturation, and partial pressure of arterial oxygen (PaO2). The rate of recovery using insufflation was faster than that from institution of mechanical ventilation. Insufflation in an intubated animal with cuff inflated led to a rapid and dangerous rise in pressure. With balloon deflated, there were no adverse pressure consequences from insufflation via the endotracheal tube at a rate of 15 l/min.
Conclusion: Insufflation through the bronchoscope for episodes of sedation-induced hypoxia should be safe and effective as long as not delivered within a closed system.
Keywords: bronchoscopy; hypoxemia; insufflation; sedation.