Oxygen desaturation during sedation for colonoscopy in elderly patients

BAGKGROUND/AIMS: Conscious sedation increases the tolerance of patients to endoscopic examination, but arterial oxygen desaturation during endoscopy h as often been reported. Elderly patients are considered to be at special ri sk. However, sedation-induced changes in cardiovascular function in the eld erly have not been well investigated. Therefore, this study examined the ef fects of sedation on pulse rate, systolic blood pressure, and arterial oxyg en saturation in elderly patients. METHODOLOGY: Twenty patients aged less than 60 years and 20 patients aged 6 0 years or more, scheduled to undergo colonoscopic removal of colorectal po lyps, received 0.05 or 0.025 mg/kg body weight, respectively, of midazolam intravenously. Before, during, and after endoscopy, pulse rate, systolic bl ood pressure, and arterial oxygen saturation were recorded every 5min with a pulse oximeter. RESULTS: Administration of midazolam had no significant effect on pulse and arterial systolic blood pressure in either group. In contrast, midazolam s ignificantly reduced the levels of arterial oxygen saturation during and af ter endoscopy in both age groups. However, although patients aged 60 years or more received midazolam at half dosage, arterial oxygen saturation durin g endoscopy was significantly lower and the incidence of 5% or more oxygen desaturation was significantly higher than in the patients aged less than 6 0 years. CONCLUSIONS: Midazolam increases the tolerance of elderly patients to endos copy, but it significantly lowers the level of arterial oxygen saturation a nd increases the incidence of desaturation. Continuous monitoring is especi ally valuable during endoscopy in the elderly.