Comparison of Intraoperative Ketamine vs. Fentanyl Use Decreases Postoperative Opioid Requirements in Trauma Patients Undergoing Cervical Spine Surgery.

BACKGROUND Postoperative airway compromise following cervical spine surgery is a potentially serious adverse event. Residual effects of anesthesia and perioperative opioids that can cause both sedation and respiratory depression further increase this risk. Ketamine is an N-methyl-d-aspartate (NMDA) receptor antagonist that provides potent analgesia without noticeable respiratory depression. We investigated whether intraoperative ketamine administration could decrease perioperative opioid requirements in trauma patients undergoing cervical spine surgery. METHODS We retrospectively reviewed anesthesia records identifying cervical spine surgeries performed between March 2014 and February 2015. All patients received a balanced anesthetic technique utilizing sevoflurane 0.5 minimum alveolar concentration (MAC) and propofol infusion (50-100 mcg/kg/min). For intraoperative analgesia, one group of patients received ketamine (N=25) and a second group received fentanyl (N=27). Cumulative opioid doses in the recovery room and until 24 hours postoperatively were recorded. RESULTS Fewer patients in the ketamine group (11/25 [44%] vs. 20/27 [74%], respectively; p = 0.03) required analgesics in the recovery room. Additionally, the total cumulative opioid requirements in the ketamine group decreased postoperatively at both 3 and 6 hours (p = 0.01). CONCLUSION Ketamine use during cervical spine surgery decreased opioid requirements in both the recovery room and in the first 6 hours postoperatively. This may have the potential to minimize opioid induced respiratory depression in a population at increased risk of airway complications related to the surgical procedure.