Identifying Changes in Ventilation Leading to Oxygen Desaturation During Procedural Sedation

The Leonardo Event Center

Nurse administered moderate sedation of patients undergoing colonoscopy is commonly used in the United States as it increases the patient’s comfort and tolerance of the procedure. Moderate sedation is defined as a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either issued alone or accompanied by light tactile stimulation. Despite the presence of trained personnel who observe recommendations to monitor the adequacy of pulmonary ventilation and respiratory rate (RR), at least one episode of hypoxemia (oxygen saturation ≤ 90%) occurs in 44-70% of patients depending on the level of sedation, patient population, and type of endoscopic procedure.1 Qadeer et al. 1 found that 35% of hypoxemic events during procedural sedation for endoscopy were not preceded by apnea or changes from baseline in RR or end-tidal CO2. We analyzed data collected from patients undergoing moderate sedation for colonoscopies to learn whether hypoxemic events could be explained by previous changes in RR, reduced tidal volume (Vt), or both.