Predictor of respiratory disturbances during gastric endoscopic submucosal dissection under deep sedation

Abstract

Background: Sedation is commonly performed for the endoscopic submucosal dissection (ESD) of early gastric cancer. Severe hypoxemia occasionally occurs due to the respiratory depression during sedation.

Aim: To establish predictive models for respiratory depression during sedation for ESD.

Methods: Thirty-five adult patients undergoing sedation using propofol and pentazocine for gastric ESDs participated in this prospective observational study. Preoperatively, a portable sleep monitor and STOP questionnaires, which are the established screening tools for sleep apnea syndrome, were utilized. Respiration during sedation was assessed by a standard polysomnography technique including the pulse oximeter, nasal pressure sensor, nasal thermistor sensor, and chest and abdominal respiratory motion sensors. The apnea-hypopnea index (AHI) was obtained using a preoperative portable sleep monitor and polysomnography during ESD. A predictive model for the AHI during sedation was developed using either the preoperative AHI or STOP questionnaire score.

Results: All ESDs were completed successfully and without complications. Seventeen patients (49%) had a preoperative AHI greater than 5/h. The intraoperative AHI was significantly greater than the preoperative AHI (12.8 ± 7.6 events/h vs 9.35 ± 11.0 events/h, P = 0.049). Among the potential predictive variables, age, body mass index, STOP questionnaire score, and preoperative AHI were significantly correlated with AHI during sedation. Multiple linear regression analysis determined either STOP questionnaire score or preoperative AHI as independent predictors for intraoperative AHI ≥ 30/h (area under the curve [AUC]: 0.707 and 0.833, respectively) and AHI between 15 and 30/h (AUC: 0.761 and 0.778, respectively).

Conclusion: The cost-effective STOP questionnaire shows performance for predicting abnormal breathing during sedation for ESD that was equivalent to that of preoperative portable sleep monitoring.

Keywords: Deep sedation; Endoscopic submucosal dissection; Polysomnography; Respiratory depression; STOP questionnaire; Sleep apnea syndrome.

Figure 1

Receiver operating characteristic curves. When the intraoperative apnea-hypopnea index (AHI) outcome was < 30 and ≥ 15 (sleep apnea syndrome: Moderate criteria), if a preoperative AHI of 5.9 is taken as the cutoff value, the sensitivity is 76.9% and the specificity is 68.2%. Similarly, for a STOP questionnaire score of 2 used as the cutoff value, the sensitivity was 75% and the specificity was 73.7%. Preoperative AHI showed an area under the curve of 0.778 and the STOP questionnaire score showed a nearly equivalent area under the curve of 0.761; the difference was not statistically significant (P = 0.8921). AUC: Area under the curve.

Figure 2

Receiver operating characteristic curves. When the intraoperative apnea-hypopnea index (AHI) outcome was ≥ 30 (sleep apnea syndrome: Severe criteria) and if a preoperative AHI of 8.3 was taken as the cutoff value, the sensitivity was 100% and the specificity was 69.7%. Similarly, for a STOP questionnaire score of 2 used as the cutoff value, the sensitivity was 100% and the specificity was 58.6%. Preoperative AHI showed an area under the curve of 0.833 and the STOP questionnaire score showed an area under the curve of 0.707. Preoperative AHI showed higher estimates and the diagnostic ability was greater; however, the difference was not statistically significant (P = 0.4450). AUC: Area under the curve.