Background: Ketamine is gaining acceptance as an agent for prehospital pain control, but the associated risks of agitation, hallucinations and sedation have raised concern about its potential to prolong emergency department (ED) length of stay (LOS). This study compared ED LOS among EMS patients who received prehospital ketamine, fentanyl or morphine specifically for pain control. We hypothesized ED LOS would not differ between patients receiving the three medications.
Methods: This retrospective observational study utilized the 2018 ESO Research Database, which includes more than 7.5 million EMS events attended by more than 1,200 agencies. Inclusion criteria were a 9-1-1 scene response; age ≥ 18 years; a recorded pain score greater than 4; an initial complaint or use of a treatment protocol indicating a painful condition; prehospital administration of ketamine, fentanyl or morphine; and ED LOS data available. Patients were excluded if they received a combination of the medications, or if there were indications that medication administration could have been for airway management (i.e., altered mental status, head injury, respiratory distress/depression) or agitation control (e.g., behavioral complaints). Kruskal-Wallis test was used to compare ED LOS among patients receiving each of the three medications. Post-hoc evaluations of between-group differences were conducted using Wilcoxon Rank Sum test and a Bonferroni-corrected alpha value of 0.017.
Results: Of 9,548 patients who met the inclusion criteria, 119 received ketamine, 1,359 received morphine, and 8,070 received fentanyl. Patient and event characteristics did not significantly differ between the three groups. Median (IQR) ED LOS was 3.5 (2.5-6.1) hours for patients who received ketamine, 4.0 (2.7-6.1) hours for patients who received morphine, and 3.7 (2.6-5.4) hours for patients who received fentanyl (p = 0.002). In post-hoc pairwise comparisons, patients who received morphine had significantly longer ED LOS than patients who received fentanyl (p < 0.001); there was no significant difference in ED LOS for patients who received ketamine vs. morphine (p = 0.161) or for patients who received ketamine vs. fentanyl (p = 0.809).
Conclusion: ED LOS is not longer for patients who receive prehospital ketamine, versus morphine or fentanyl, for management of isolated painful non-cardiorespiratory conditions.
Keywords: emergency medical services; ketamine; pain management.