Comparison of Nebulized Ketamine to Intravenous Sub-Dissociative Dose Ketamine for Pain

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA)/glutamate receptor complex antagonist that decreases pain by diminishing central sensitization, hyperalgesia, and "wind-up" phenomenon at the level of the spinal cord (dorsal ganglion) and central nervous system (1). Ketamine administration in sub-dissociative doses (SDK) of 0.1-0.3 mg/kg in pre-hospital settings and in the ED results in effective pain relief in patients with acute traumatic and non-traumatic pain, chronic non-cancer and cancer pain, and in patients with opioid-tolerant pain by virtue of providing anti-hyperalgesia, anti-allodynia, and anti-tolerance (2-4). Two commonly utilized routes of SDK administration in the ED include an intravenous route (intravenous push dose or short infusion) and intranasal route. In the situation when intravenous access is not readily available or unobtainable, and intranasal route is not feasible, another non-invasive route of ketamine administration such as inhalation via Breath-Actuated Nebulizer (BAN) is coming into the play. The BAN allows a controlled patient-initiated delivery of analgesics in titratable fashion. Nebulized administration of ketamine has been studied in the areas of acute postoperative pain management (post-intubational sore throat), in anesthesia (pre-medication for general anesthesia,) and in managing cancer pain, and status asthmaticus therapy. However, our research team has published a case series of 5 patients receiving nebulized ketamine for a variety of acute painful conditions and has recently completed a randomized double-blind trial of 120 adult patients that evaluated analgesic efficacy and safety of nebulized ketamine at three different dosing regimens for acute pain in the ED. Currently, we are conducting two additional studies evaluating the role of nebulized ketamine in pediatric ED and pre-hospital arena. In this study the investigators hypothesize that intravenous sub-dissociative-dose ketamine of 0.3 mg/kg will provide b