Ketamine, propofol and low dose remifentanil versus propofol and remifentanil for ERCP outside the operating room: is ketamine not only a "rescue drug"?

BACKGROUND: Endoscopic retrograde cholangiopancreatography ERCP is a painful and long procedure requiring transient deep analgesia and conscious sedation. An ideal anaesthetic that guarantees a rapid and smooth induction, good quality of maintenance, lack of adverse effects and rapid recovery is still lacking. This study aimed to compare safety and efficacy of a continuous infusion of low dose remifentanil plus ketamine combined with propofol in comparison to the standard regimen dose of remifentanil plus propofol continuous infusion during ERCP.

MATERIAL/METHODS: 322 ASAI-III patients, 18-85 years old and scheduled for planned ERCP were randomized. Exclusion criteria were a predictable difficult airway, drug allergy, and ASA IV-V patients. We evaluated Propofol 1 mg/kg/h plus Remifentanil 0.25 µg/kg/min (GR) vs. Propofol 1 mg/kg/h plus Ketamine 5 µg/kg/min and Remifentanil 0.1 µg/kg/min (GK). Main outcome measures were respiratory depression, nausea/vomiting, quality of intraoperative conditions, and discharge time. P≤0.05 was statistically significant (95% CI).

RESULTS: Respiratory depression was observed in 25 patients in the GR group compared to 9 patients in the GK group (p=0.0035). ERCP was interrupted in 9 cases of GR vs. no cases in GK; patients ventilated without any complication. Mean discharge time was 20±5 min in GK and 35±6 min in GR (p=0.0078) and transfer to the ward delayed because of nausea and vomiting in 30 patients in GR vs. 5 patients in GK (p=0.0024). Quality of intraoperative conditions was rated highly satisfactory in 92% of GK vs. 67% of GR (p=0.028).

CONCLUSIONS: The drug combination used in GK confers clinical advantages because it avoids deep sedation, maintains adequate analgesia with conscious sedation, and achieves lower incidence of postprocedural nausea and vomiting with shorter discharge times.