Polysomnographic assessment of respiratory disturbance during deep propofol sedation for endoscopic submucosal dissection of gastric tumors

Abstract

Aim: To investigate that polysomnographic monitoring can accurately evaluate respiratory disturbance incidence during sedation for gastrointestinal endoscopy compare to pulse oximetry alone.

Methods: This prospective observational study included 10 elderly patients with early gastric cancer undergoing endoscopic submucosal dissection (ESD) under propofol sedation. Apart from routine cardiorespiratory monitoring, polysomnography measurements were acquired. The primary hypothesis was tested by comparing the apnea hypopnea index (AHI), defined as the number of apnea and hypopnea instances per hour during sedation, with and without hypoxemia; hypoxemia was defined as the reduction in oxygen saturation by ≥ 3% from baseline.

Results: Polysomnography (PSG) detected 207 respiratory disturbances in the 10 patients. PSG yielded a significantly greater AHI (10.44 ± 5.68/h) compared with pulse oximetry (1.54 ± 1.81/h, P < 0.001), thus supporting our hypothesis. Obstructive AHI (9.26 ± 5.44/h) was significantly greater than central AHI (1.19 ± 0.90/h, P < 0.001). Compared with pulse oximetry, PSG detected the 25 instances of respiratory disturbances with hypoxemia 107.4 s earlier on average.

Conclusion: Compared with pulse oximetry, PSG can better detect respiratory irregularities and thus provide superior AHI values, leading to avoidance of fatal respiratory complications during ESD under propofol-induced sedation.

Keywords: Endoscopic submucosal dissection; Hypoxemia; Polysomnography; Propofol; Pulse oximetry; Sedation.

Figure 1

Representative polysomnographic recording of a long central apnea episode occurring soon after a bolus injection of propofol (2 mg/kg) and pentazocine (7.5 mg), followed by continuous infusion of propofol (2 mg/kg per hour) in a 67-year-old female. Chin-lift airway maneuver (shown by an arrowhead) restored breathing once; however, central apnea redeveloped, resulting in severe hypoxemia (SaO₂, 67%); the hypoxemia reversed gradually with improvement in breathing efforts. Polysomnography could detect apnea 40 s before the observed decrease in SaO₂ levels.

Figure 2

Representative polysomnograph of periodic obstructive apnea that occurred during endoscopic submucosal dissection under propofol sedation. Thoraco-abdominal respiratory movements showed obstructive disturbance represented by paradoxical movements. Despite these long apneas lasting more than one minute, SaO₂ levels remained > 95%.

Figure 3

Typical polysomnograph of an obstructive hypopnea that occurred during endoscopic submucosal dissection under propofol sedation. Obstructive hypopnea episodes were diagnosed based on paradoxical thoraco-abdominal wall movements and flattened nasal pressure waves and resolved spontaneously with gradual increase in airflow caused by an increase in breathing effort.

Figure 4

Frequency of respiratory disturbances detected by pulse oximetry and polysomnography. All patients experienced respiratory disturbances during propofol sedation (total AHI: 10.44 ± 5.68/h). Total apnea hypopnea index (AHI) was significantly greater with polysomnography than with pulse oximetry (1.54 ± 1.81/h, P < 0.001). Obstructive AHI (9.26 ± 5.44/h) was significantly greater than central AHI (1.19 ± 0.90/h, P < 0.001).