Letter to the Editor: Low-dose ketamine for pain control in patients with multiple rib fractures

摘要

To the Editor In a randomized control trial by Carver and colleagues1 assessing ketamine infusion for pain control in adult patients with multiple rib fractures, they showed that low-dose ketamine failed to decrease numeric pain score (NPS) or oral morphine equivalent (OME) within the overall cohort, but a decrease in OME was noted in patients with an Injury Severity Score greater than 15. Many things of this study were correctly done. The authors used a prospective, randomized, double-blind placebo-controlled trial with a consistent study subjects (multiple rib fractures). Furthermore, they attempted to control most factors affecting the pain control, such as age, gender, Injury Severity Score, and others. All of these are strengths in the study. Other than the limitations described in the discussion, however, we noted several issues in this study that were not addressed well. First, the area under the curve for NPS was used as primary endpoint for group comparison. Besides, the pain regimen was not standardized; however, the authors did not clearly describe whether an NPS goal of satisfied pain control was included in their design. Given that the mean areas under the curve for NPS at 12 hours to 24 hours and 24 hours to 48 hours were greater than 5 in both groups, we were concerned that a satisfied pain control was not achieved in all patients. Most importantly, it was unclear how opiate and non-opiate-based medical treatments were given and if two groups were comparable with patients' satisfaction for pain control. Thus, we argue that no significant difference in NPS for overall cohort should be attributable to the lack of standardized pain regimen and satisfied pain control goal, rather than failure of low-dose ketamine for pain control.