V. Ly1, J. Sharib1, L. Chen2, K. Kirkwood1 2University Of California – San Francisco,Anesthesia,San Francisco, CA, USA 1University Of California – San Francisco,Surgical Oncology,San Francisco, CA, USA
Introduction:
Epidural analgesia following pancreatectomy has become widely adopted; however, high epidural rates are often associated with early hypotensive events that require rate reduction and fluid resuscitation. It is unclear which patients are most at risk for such events. Continuous subanesthetic ketamine infusion reduces opioid consumption after major abdominal surgery. The effects of ketamine added to epidural analgesia have not been well studied in patients undergoing pancreatectomy. This study evaluates the safety and postoperative analgesic requirements in patients who received continuous ketamine infusion as an adjunct to epidural analgesia following pancreatectomy.
Methods:
A retrospective data analysis was conducted on 234 patients undergoing pancreaticoduodenectomy (n=165) or distal pancreatectomy (n=69) at UCSF Medical Center between January 2014 and January 2017. Patient demographics, including history of prior opiate use, along with perioperative fentanyl-ropivacaine epidural and continuous intravenous ketamine rates were collected. Oral morphine equivalents (OME) and visual analogue pain scales (VAS) were recorded at post op day 0, 1, 2, 3, and 4. To assess for safety, epidural rate decreases due to hypotension within the first 24 hours post op and ketamine-related adverse events were recorded.
Results:
Epidural (n=197) and other opiate analgesia (n=234) were administered perioperatively per surgeon preferences and institutional standards. Continuous ketamine infusion was given intraoperatively, postoperatively, or both in 71 patients, with a trend toward preferential use in patients with prior opiate exposure. Ketamine infusion was not associated with hypotensive events, daily maximum epidural rates, or significant epidural rate changes on postoperative days 0-4. OMEs and VAS were similar between groups, regardless of prior opiate use. Patients with American Society of Anesthesia (ASA) class 3 or 4 (n=111) were more likely to require epidural rate decreases (OR 2.37, 95%CI 1.3-4.2, p = 0.003) and associated interventions in the first 24 hours post op. Three patients reported ketamine-related adverse events such as unpleasant dreams and hallucinations.
Conclusion:
Subanesthetic ketamine infusion as an adjunct to epidural analgesia for pancreatic surgery patients is safe. Patients with ASA classification 3 or 4 experience more hypotensive events which require epidural rate decreases in the first postoperative day following pancreatectomy. Further study is required to assess whether ketamine infusion allows for use of lower epidural rates, reduces post op opioid consumption, or improves pain score in the early postoperative period.