Prehospital pain: epidemiology and management in Victoria, Australia

Abstract

Pain is a commonly encountered condition in the prehospital and emergency medicine settings, and is associated with significant burden of disease. This thesis explores the epidemiology of pain in the Victorian prehospital setting, and factors associated with the likelihood of clinically important pain severity reduction were identified from the interrogation of a large patient record database. Seven factors were found to be associated with the likelihood of clinically important pain reduction following multivariate analyses. These included: age, time criticality of the patient, pain aetiology, initial pain severity, analgesic agent or combination administered to the patient, scene time, and transport time. In 2007, ketamine was trialled in the prehospital setting as an analgesic agent. In this prospective, randomised controlled trial, the administration of morphine followed by ketamine was found to be superior to morphine alone in the reduction of pain intensity in adult patients with moderate to severe pain following trauma in the prehospital setting. Intravenous ketamine provided safe and effective analgesia to adult patients following injury. After accounting for differences between trial cluster sites, patients in the ketamine group had a mean verbal numerical rating scale (VNRS) pain reduction of 5.6 points compared with the M-group of 3.2 points (p<0.0001). This study followed participants up to 12 months following enrolment into the ketamine study, identified those who continued to suffer from persistent pain, and assessed their health-related quality of life using the SF-36 questionnaire. Statistically and clinically, there was no difference in the long term follow up between study groups with respect to the summary measures, subscale measures or global pain score. In light of the superiority of intravenous ketamine over morphine to reduce pain intensity in patients with moderate to severe traumatic injury, this agent warrants consideration by all emergency medical services (EMS) who have appropriate training and clinical governance. Furthermore, ketamine was administered in a safe manner in this non-physician EMS setting. It is likely that this work will result in Ambulance Victoria introducing ketamine as an alternative analgesic agent for the prehospital management of moderate to severe pain in trauma patients, and has the potential to influence change in EMS and emergency medicine practice nationally and internationally. In time, hopefully, these studies will make a major contribution to the early management of injured patients. Improved early management of pain and interventions aimed at other related factors could lead to more efficient rehabilitation, demonstrable decreases in morbidity, and improved quality of life.