Safety of Propofol for Conscious Sedation During Endoscopic Procedures in High-Risk Patients–A Prospective, Controlled Study Ludwig T. Heuss, M.D., M.B.A., Patrizia Schnieper, M.D., Juergen Drewe, M.D., Eric Pflimlin, R.N., and Christoph Beglinger, M.D. Department of Gastroenterology and Department of Clinical Pharmacology, University Hospital Basel, Basel, Switzerland OBJECTIVE: Propofol, a rapidly-acting hypnotic agent, is increasingly being used for endoscopic sedation. Serious adverse effects, including respiratory and cardiovascular depression, make many endoscopists reluctant to use propo- fol in critically ill patients. This study characterizes propo- fol’s safety profile in consecutive high-risk patients (Amer- ican Society of Anesthesiologists [ASA] classes III and IV) compared with matched subjects (ASA classes I and II). METHODS: During a 19-month period, 1370 at risk-patients were sedated with propofol, of whom 47% (614 ASA III, 28 ASA IV) were age matched with 642 consecutive patients of the same gender and age assigned to ASA classes I and II and undergoing the same endoscopic procedures (395 gas- troscopies, 201 colonoscopies, 14 combined). Registered nurses performed all sedations by propofol dose titration while carefully monitoring arterial oxygen saturation, heart rate, and blood pressure. RESULTS: No major complications occurred among the crit- ically ill patients. There was, however, an increased risk for a short relevant oxygen desaturation (90%) of 3.6% for ASA III and IV versus 1.7% for ASA I and II (p = 0.036). In four versus one case, short mask ventilation was neces- sary. Also, a greater proportion of patients showed a 5% oxygen saturation decrease. There was no pronounced in- fluence on arterial pressure or heart rate and no perforations in 336 colonoscopies. CONCLUSIONS: With careful monitoring, propofol sedation during GI endoscopies is safe, even for high-risk patients. Considering their higher comorbidity and tendency toward oxygen desaturation, they need particularly careful moni- toring, and the required dose is, on mean, 10 –20% lower than in ASA classes I and II. (Am J Gastroenterol 2003;98: 1751–1757. © 2003 by Am. Coll. of Gastroenterology) INTRODUCTION GI endoscopies are widely perceived as being uncomfort- able examinations, and physicians find themselves con- fronted with a growing number of patients requesting seda- tion during the procedure. Since the 1980s, this has typically been undertaken with i.v. benzodiazepines, such as diaze- pam and midazolam, and opiates (1–3). These compounds are generally well tolerated; however, significant morbidity has been reported using these agents (4, 5). Although seda- tion with benzodiazepines, especially midazolam, exerts anxiolytic and amnesic effects (both desirable for endosco- py), these compounds also have certain disadvantages, such as a long duration of action, antegrade amnesia, and pro- longed recovery (6, 7). Because it induces conscious seda- tion, propofol, an ultrashort-acting i.v. hypnotic agent, is increasingly being used for endoscopic procedures. There are several advantages to propofol: it has a short half-life (t 1 /2 distribution 2– 4 min) compared with midazolam (about 30 min), and thus recovery from sedation is much faster than for midazolam. This makes it especially suitable in an out- patient setting as it remarkably reduces the need for post- procedure surveillance (8 –10). However, as is the case with the benzodiazepines, propofol also has unwanted effects. Likewise, especially when used by personnel who are not specially trained with this agent, there are certain doubts concerning the safety of propofol, specifically, the risk of respiratory depression and the risk of hypotension and bra- dycardia (11). In contrast to the benzodiazepines, there is no antidote for propofol. In cases of overdose, the patient has to be stabilized with artificial bag ventilation until spontaneous respiration reappears. Doubts concerning the safety of propopfol, especially the concern that there is a greater susceptibility to these serious unwanted effects (12), have made many endoscopists most reluctant to use propofol in critically ill patients (8, 11, 13–20). However, a major proportion of GI patients who require endoscopic intervention have multiple concomitant diseases or are in a critical state of health. Using a cautious titration protocol, this study characterizes the safety profile of propofol in consecutive high-risk patients stratified into American Society of Anesthesiologists (ASA) classes III and IV and compares it with matched patients from ASA classes I and II. THE AMERICAN JOURNAL OF GASTROENTEROLOGY Vol. 98, No. 8, 2003 © 2003 by Am. Coll. of Gastroenterology ISSN 0002-9270/03/$30.00 Published by Elsevier Inc. doi:10.1016/S0002-9270(03)00447-7