Safety and Speed of Onset of a Fixed Dose of Intravenous Hydromorphone in the Treatment of Adult Patients Presenting to the Emergency Department With Acute Severe Pain

Introduction and Background: Pain is cited as the most frequent reason for visits to emergency departments (EDs) (McCaig, 2001). It can be estimated from the National Hospital Ambulatory Medical Care Survey, an annual survey of a representative sample of visits to US EDs, that there are 17 million visits per year to US EDs for specific complaints of pain, 29 million visits including "back symptoms" and "injuries not otherwise specified" as well as specific mentions of pain. However it is widely acknowledged that pain is seriously under-treated in the ED as well as in other health care settings (Ducharme, 1996; Selbst, 1990; Wilson, 1989). The concern regarding under-treatment is reflected in new standards for pain management developed by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) requiring assessment of pain at triage in the ED and referring to pain measurement as the "fifth vital sign" (Philips, 2000).

Proper pain management is a tremendous challenge to ED physicians as pain is not only a noxious experience but also a symptom of injury and disease that needs to be understood and appropriately treated. Further complicating pain management is the large interpersonal variability in pain perception and expression reflecting cultural, contextual, and individual differences between people. Reasons for under-treating pain include concern over side effects of opioids, perception of pain complaints as possible drug-seeking behavior, under-staffing, concern that analgesics will mask symptoms or delay early diagnosis and treatment, and contribute to risks of tolerance and dependence in vulnerable patients.

Morphine has long been considered the gold standard in pain control. Hydromorphone is another powerful opioid that has been used extensively for the management of post-operative pain and morphine-resistant cancer-related pain. A recent Cochrane review on the use of hydromorphone found 32 studies that focused on acute pain (Quigley, 2003). Of these 32 studies, only 9 involved intravenous forms of hydromorphone (Coda, 1997; Collins, 1996; Deutsch, 1968; Jasani, 1994; Liu, 1995; Mahler, 1975; Rapp, 1996; Searle, 1994; Urquhart, 1988). Of these 8 studies, 5 involved patient controlled analgesia, and only 1 study compared IV hydromorphone to IV morphine (Mahler, 1975). The Cochrane review concludes that there are substantial gaps in the understanding of the efficacy and potency of hydromorphone.

We have recently completed a study in non-elderly adult patients (IRB 04-08-225) that showed that weight-based IV hydromorphone provides better pain relief than weight-based IV morphine. This result was both statistically and clinically significant. We also demonstrated in this same study that IV hydromorphone has a faster onset and also provided statistically significant improvement in pain relief at 5 minutes as compared to IV morphine.

Although weight-based dosing of medications is common in pediatrics, most emergency physicians use whole integer amounts of pain medications. IV hydromorphone is more potent than IV morphine, so the dosages given are much smaller. We therefore wish to give a standard 2 mg dose of IV hydromorphone to all non-elderly adult patients weighing at least 150 lbs presenting to the ED with acute severe pain. We wish to examine the safety and speed of onset of hydromorphone using such a protocol.