The Effect of Low Dose Ketamine on the Need for Morphine in Patients with Multiple Trauma in Emergency Department

Pain is one of the most frequent problems in patients visiting emergency departments (EDs) so that 70% of emergency visits are due to pain (1-3). Adequate analgesia following trauma is a central aspect of emergency medical treatment before and after hospital admission (4). Acute pain and trauma are often closely related to one another, as pain is induced by noxious stimuli at the site of tissue damage (1). Pain is also the main complaint of patients seeking help in emergency care. As a consequence, patients suffer pain unnecessarily, and adverse physiological and psychological effects occur (2). Trauma patients, report low satisfaction with their pain management (5). In addition, trauma patients who present with multiple injuries, substance abuse, delayed care, as well as psychological and emotional issues complicate the care process (5,6). Improved pain management is not only the patient right, but also it prompts early healing, reduces patient’s stress response, shortens hospital length of stay, lowers costs, diminishes risk of chronic pain due to neuroplasticity, and ultimately reduces morbidity and improve long-term outcomes (5-8). Abstract Aim: There are a few analgesic drugs (morphine, ketamine, Paracetamol, etc.) used for pain control in injury patients. Previous studies showed that low-dose ketamine (doses less than 1 mg/kg) promptly and satisfactorily resolved pain. This study aimed to compare the analgesic effects of morphine with placebo (MP group) to that of a combination of morphine with ketamine (MK group) for patients with multiple trauma (MT) in the emergency department (ED). Materials and Methods: This randomized, controlled, double-blinded clinical trial was conducted in the ED of two university teaching hospitals. Seventy multiple trauma patients aged between 16 and 50 years with a severe acute pain defined as a visual analog scale (VAS) score of at least 70 (between 0 and 100) were enrolled. Patients were randomly assigned to receive intravenous morphine (0.1 mg/kg) with placebo or morphine (0.05 mg/kg) with low-dose ketamine (0.3 mg/kg) for pain control. The pain intensity was evaluated before and 10, 20, 30, and 60 minutes after the intervention, and probable side effects were recorded. Efficient analgesia was defined as a VAS score not exceeding 30. If the VAS score was still above 30, additional morphine (3 mg) was administered for both groups. The primary outcome was the VAS score at 30 minutes. Results: Seventy patients were enrolled in this study. There was no difference between the groups in terms of demographic characteristics or vital signs and baseline pain scores. The pain intensity decreased significantly in both groups 30 minutes after the intervention. However, there was no significant difference between the mean VAS scores of the two groups before and after the intervention. Morphine consumption was significantly lower in the MK group versus the MP group (9.3±2.2 vs 6.1±2.7, p=0.01). In addition, there was no significant difference between the two groups in terms of complications (p>0.05). Conclusion: Low-dose ketamine in combination with morphine significantly reduced the need for an additional dose of morphine without increasing the complication rate related to morphine alone.