Alternative sedation for the higher risk endoscopy: a randomized controlled trial of ketamine use in endoscopic retrograde cholangiopancreatography

Abstract

Objective. Sedation for endoscopy carries an element of cardiorespiratory risk, more significant for certain procedures and in certain patient groups. Ketamine has features which make it an attractive agent for sedation during the higher risk endoscopy; the objectives of this pilot trial were to assess the effectiveness and tolerability of ketamine as a primary agent for sedation during endoscopy. Methods. The study was a prospective randomized controlled trial, in which American Society of Anesthesiologists’ (ASA) class 1–3 patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) received either conventional sedation with midazolam and pethidine or a combination of midazolam and ketamine. Patients were monitored physiologically and in respect to depth of sedation (Modified Observer’s Assessment of Alertness/Sedation score) and were observed post procedure for evidence of emergence reactions or other complications. After full recovery, patients completed a questionnaire on their experiences, with particular emphasis on vivid dreaming or other complications attributable to ketamine. Results. Demographically, control (n = 18) and study (n = 19) groups were similar in makeup. Median midazolam dose was 2 mg (interquartile range [IQR] = 1–3) and 2 mg (IQR = 2–3), respectively (p = 0.98); median procedure duration was 25.5 min (IQR = 17–30) and 21.0 min (IQR = 15–34) (p = 0.92). Median satisfaction with sedation (scored from 0 to 4) was 3.5 (range 1–4) and 4 (range 2–4) respectively (p = 0.88). No patient in either group experienced emergence reactions, dysphoria, or vivid dreaming. Conclusion. In this pilot study, sedation for endoscopy with ketamine and midazolam was as effective as conventional sedation, as acceptable to patients, and was not associated with dysphoric events. Ketamine may have potential as an agent for sedation in higher risk patients.

Key Words:

• capnography
• endoscopic retrograde cholangiopancreatography
• ketamine
• sedation

Acknowledgments

The authors would like to thank Boston Scientific, Breakspear Park, Breakspear Way, Hemel Hempstead, Hertfordshire, HP2 4TZ, UK, and Ferring Pharmaceuticals Ltd, The Courtyard, Waterside Drive, Langley, Slough, Berkshire, SL3 6EZ, UK, for financial support, and Datascope Patient Monitoring, Mindray (UK) Ltd, for the loan of monitoring equipment. The authors would also like to thank the Research and Development Department at the Royal Albert Edward Infirmary for all their help and support throughout, Elizabeth Connors, Department of Social and Psychological Sciences, Edgehill University, Ormskirk, Lancashire, L39 4QP, UK, for her assistance with randomization and with statistics in general, and Catherine Fullwood, Medical Statistican, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, NIHR Manchester Biomedical Research Centre, for additional advice on data analysis and presentation.

Declaration of interests: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.