Capnography Monitoring During Procedural Sedation: A Prospective Assessment

Procedural sedation performed outside the operating room has traditionally relied on pulse oximetry and intermittent clinical observation to detect respiratory compromise, but both lag behind the actual onset of hypoventilation or apnea, particularly when patients receive supplemental oxygen. Capnography, which continuously measures exhaled carbon dioxide, detects apnea, hypoventilation, and airway obstruction well before saturation begins to fall, and this review synthesizes the prospective and randomized evidence for its use across endoscopic, emergency department, dental, obstetric, and pediatric sedation settings. Across these contexts, capnography-guided monitoring is consistently associated with earlier recognition of ventilatory abnormalities and, in most trials, a reduced incidence of oxygen desaturation and hypoxemia relative to standard monitoring alone. Evidence that earlier detection translates into a reduction in rarer, more serious outcomes such as unplanned intubation remains less mature, constrained by low baseline event rates and modest individual trial sizes, and practical concerns including signal artifact and alarm fatigue temper unqualified enthusiasm for the technology. We conclude that the physiologic case for capnography during moderate and deep procedural sedation is now well supported, and that thoughtful implementation with adequate staff training is the more pressing remaining question rather than whether the monitor detects respiratory compromise earlier than pulse oximetry.