Incidence and Nature of Respiratory Events in Patients Undergoing Bronchoscopy Under Conscious Sedation

Background: During diagnostic bronchoscopies, conscious sedation improves patient tolerance, but it can contribute to hypercapnia and hypoxia by various mechanisms including depression of ventilatory drive. This prospective study was undertaken to determine the frequency of respiratory events and associated oxygen desaturations during bronchoscopy with conscious sedation. Patients and Methods: The Nox-T3 monitoring system was placed before starting the bronchoscopy and remained in place for 30 minutes following the procedure. The primary endpoint was the occurrence of obstructive and central apneic events during bronchoscopy under conscious sedation. Results: Obstructive events (apnea and hypopnea) occurred in 100% of patients (n=31), and central apneas occurred in 58% of patients (n=18) during the procedure with a median of 9 and 2 events per patient, respectively. During recovery, a significant proportion of patients had detectable obstructive (86%) and central (36%) events. Higher body mass index was associated with oxygen desaturation to <90% and with the need for escalation of care. Furthermore, a conscious sedation regimen that included propofol was significantly associated with central apneic events. Conclusion: Respiratory events are common during and immediately postprocedure after conscious sedation for bronchoscopy. Most events are obstructive, and the use of propofol predisposes to central apneas during the procedure. Both types of events are associated with a higher body mass index. Oxygen desaturation to <90% triggers escalation of care. A further prospective study will be required to determine the clinical significance of these apneic events and whether alleviating these events will improve the safety and outcomes of bronchoscopic procedures performed under conscious sedation.