A fixed nitrous oxide/oxygen mixture as an analgesic for trauma patients in emergency department: study protocol for a randomized, controlled trial

Acute pain is always the most common complaint in Emergency Department admissions and options for analgesia are limited. Nitrous oxide/oxygen possess many properties showing it may be an ideal analgesic method for the Emergency Department; it is quick-acting, well-tolerated, and does not mask signs and symptoms. The aim of this study is to evaluate the safety and analgesic effect of the fixed nitrous oxide/oxygen mixture for trauma patients in a busy emergency environment. The randomized, double-blind, prospective, placebo-controlled study will be carried out in the Emergency Department of General Hospital of Ningxia Medical University. The target research objects are trauma patients who present to the Emergency Department and report moderate to severe intensities of acute pain. A total of 90 patients will be recruited and randomly assigned into the treatment and control group. The treatment group will receive conventional pain treatment plus nitrous oxide/oxygen mixture and the control group will receive conventional pain treatment plus oxygen. Neither patients, nor investigators, nor data collectors will know the nature of the gas mixture in each cylinder and the randomization list. Outcomes will be monitored at baseline(T0), 5 min (T1), and 15 min (T2) after the beginning of intervention and at 5 min post intervention (T3) for each group. The primary outcome is the level of pain relief after the initial administering of the intervention at T1, T2, and T3. Secondary outcomes include adverse events, physiological parameters, total time of the gas administration, satisfaction from both patients and healthcare professionals, and the acceptance of patients. Our previous studies suggested that a fixed nitrous oxide/oxygen mixture was an efficacious analgesic for the management of burning dressing pain and breakthrough cancer pain. The results of this study will provide a more in-depth understanding of the effect of this gas. If this treatment proves successful, it could help to generate preliminary guidelines and be implemented widely in trauma patients with pain in Emergency Departments. Chinese Clinical Trial Register, ChiCTR-INR-16007807 . Registered on 21 January 2016.