Safety of Hydromorphone in 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.

Our general thought is that to develop more evidence based practice, we need to generate more practice based evidence. This study attempts to do this as it is practiced based and very practical. We wish to take the drug as it comes (2mg Dilaudid in an ampule) and use all of it, thus alleviating the need to waste the excess opioid (and alleviating the need to find a second person to witness the wasting). We also wish to use a weight cutoff that everyone can remember (150 lbs). We believe that this protocol will provide greater pain relief and help address the issue of inadequate pain treatment, or "oligoanalgesia", that is prominent in the literature (Sobel 2002, Wilson, 1989, Goldfrank 2000).

Finally, in our multiple studies of pain conducted in the ED, we have found a relatively high rate of refusal to receive pain medication. We think this may represent a component to the problem of oligoanalgesia that is widespread in the ED. We wish to investigate the reasons for patient refusal to receiving parental opioid medications (fear of addiction, side effects, etc).

Inclusion criteria

• Age greater than 21 years
• Age less than 65 years of age
• Pain with onset within 7 days
• ED attending physician's judgment that patient's pain warrants use of morphine
• Normal mental status

Exclusion criteria

• Prior use of methadone
• Use of other opioids or tramadol within past seven days
• Prior adverse reaction to hydromorphone.
• Chronic pain syndrome
• Alcohol intoxication
• SBP <90 mm Hg
• Use of MAO inhibitors in past 30 days
• C02 measurement greater than 46