Effects of transcutaneous electrical acupuncture point stimulation on peripheral capillary oxygen saturation in elderly patients undergoing colonoscopy with sedation: a prospective randomized controlled trial

Introduction: This study investigated whether transcutaneous electrical acupuncture point stimulation (TEAS) at PC6 can reduce the proportion of elderly patients experiencing a drop of > 4% in peripheral capillary oxygen saturation (SpO(2)) while undergoing colonoscopy under sedation. Methods: A total of 32 elderly patients (aged > 65 years) scheduled for colonoscopy were randomly assigned in a 1:1 ratio to receive either real or sham TEAS (treatment or control groups, respectively). Each patient received oxygen (2 L/min) delivered routinely via nasal cannula. The treatment group was given TEAS at PC6 for 20 min at 2 Hz frequency and 6 mA intensity; the control group underwent the same procedures but with zero frequency/intensity. SpO(2) and other physiological parameters were measured prior to sedation and colonoscopy (baseline) and at seven other timepoints through departure from recovery. Depth of anesthesia was measured using a Narcotrend monitor. Results: Significantly fewer patients in the treatment group experienced a > 4% decrease from baseline SpO(2) (2/16) than patients in the control group (10/16; p = 0.004). The two groups were comparable with regard to respiratory rate, systolic and diastolic blood pressures, mean arterial pressure, and heart rate. Conclusion: TEAS applied at PC6 with 2 Hz frequency was feasible and may be helpful in reducing the rate of hypoxia in elderly patients during colonoscopy.