Sub-Dissociative Ketamine Use in the Emergency Department for Treatment of Suspected Acute Nephrolithiasis: The SKANS Study

CONTEXT: Currently, there is no standard therapy for treatment of acute renal colic. With the increased scrutiny and controversy now surrounding opioids, the authors identified a need to investigate an alternative medication for pain control. As such, they sought to determine the efficacy of sub-dissociative (i.e., low) doses (0.3 mg/kg) of ketamine in providing Emergency Department (ED) patients acute pain management for renal colic secondary to nephrolithiasis. METHODS: After institutional review board (IRB) approval, the authors conducted a non-blinded, prospective clinical study. A convenience sample of n = 34 patients from the ED of a Western Michigan-based health system with suspected renal colic received one intravenous dose of ketorolac, 30 mg if over 50 kg body weight or 15 mg if under 50 kg In patients weighing greater than 50 kg, up to two doses of sub-dissociative ketamine were then given to further control pain. Pain was assessed at times 0, 30, 60, 90 and 120 minutes. RESULTS: There was a statistically significant pain reduction with administration of sub-dissociative ketamine, with 24 (69.2%) patients reporting an average reduction in pain score > 30% (t = 3.16, p = 0.004). Initial average pain scores for patients receiving sub-dissociative ketamine averaged 7.76 (SD = 2.55) on the 11-point verbal Pain Numeric Rating Scale. After a first dose of ketamine, patients’ average pain score was 3.56 (SD = 0.74) at 30 minutes. After two hours, patients’ average score was 2.56 (SD = 0.65), indicating that pain control was still effective over time with no statistically significant change in pain scores. Additionally, there was no statistically significant difference in pain reduction observed between genders (t = -0.192, p = 0.850). CONCLUSIONS: Based on these results, sub-dissociative ketamine may be considered a reasonable and effective supplemental non-opiate treatment option for suspected renal colic in otherwise healthy 18-70-year-old patients and could provide an effective alternative to traditional therapies. Further studies utilizing this methodology with larger, more generalizable samples are needed to further validate these findings.