For better pain control, add a benzo? (Part 1 - Trauma)

If a patient is in pain, should we also be treating their anxiety more aggressively? Some medical practitioners feel strongly that we should be.  In part 1, I'll discuss the evidence for using "benzos" (e.g. midazolam, lorazepam) for traumatic pain. The (forthcoming) part 2 will discuss using benzos to treat the pain of cardiac ischemia. 

Bourbon, for example, can treat the anxiety of MI.
Source: Not the NEJM

Trauma, pain, and benzos
Many paramedics believe that they could control traumatic pain better, and reduce morphine or fentanyl dosing, if they were allowed to add a benzodiazepine, like midazolam or Ativan. Different reasons are offered for this approach, such as the role of anxiety, the spasming of muscles in trauma, or the difficulty in controlling pain quickly with just opioids. An interesting new EMS study adds some evidence to this discussion.

The French authors of  "Does midazolam enhance pain control in prehospital management of traumatic severe pain?" enrolled patients who had a traumatic injury, and who described their pain as at least a "6" on a 10-point scale. 

All of the patients got morphine, and good doses too! The first dose was 0.1 mg/kg, and then repeat doses of 3 mg PRN every 3 minutes were administered, until the pain was down to a “3.” 

Half of these patients also received 0.04 mg/kg IV of midazolam at the same time as the initial dose of morphine, while the other half received a placebo injection.

So, did adding the benzo help? It appears not. Surprisingly, the patients who received midazolam had about the same pain relief as the placebo group. 

Unsurprisingly, they also had much higher rates of sedation: 44%, versus only 7% for the placebo group. They also found a strong trend for more hypoxia in the benzo group: 13% versus 2% for placebo. Lastly, there was no difference in the total doses of morphine given.

So, unless you're looking to "snow" more patients, this isn't a good approach!


How does this agree with other studies?

Pretty well. For example, an ED study done with kids with fractured arms also looked at morphine ± midazolam for pain control. Similar to the present study, they found no advantage in pain control, but more "drowsiness." (In the graph, "VAS" means pain level.)

The Bottom Line
When I interviewed medics for a study I did a few years ago, I was surprised to hear that many medics, from both rural and urban locations across New England, felt strongly about giving benzos for acute traumatic pain.  Here's a sample quote from one of the subjects:

Ref.

Despite having personally worked as a medic at a few of the places I visited, I was surprised to hear this perspective. Adding benzos for pain control is not common (or usually even permitted) in the emergency departments where these medics trained. 

Unless we are trying to sedate a patient, severe pain is probably best controlled with opioids only.