All posts by TheTraumaPro

Using MRI To Predict Outcome From Diffuse Axonal Injury (DAI)

Has this happened to you? A patient with a serious head injury is not waking up as expected. There were a few punctate hemorrhages seen on the initial CT scan. Your neurosurgery colleague orders an MRI to “provide a prognosis on the patient’s injury.”

Is this a legitimate request? Sure, MRI is very sensitive at detecting very small hemorrhages that may signal the presence of diffuse axonal injury (DAI). But do more abnormalities on MRI equal a poorer prognosis or longer recovery time?

A group from Vanderbilt presented their data from a retrospective cohort study at EAST earlier this year.  They reviewed 7 years of data from 2006 to 2012, including all patients with a head CT positive for intracranial injury and an MRI within 2 weeks. They excluded penetrating injuries and patients with psychiatric or neurologic disorders. They analyzed information on three year mortality, functional outcome, and quality of life.

Here are the factoids:

  • A total of 311 patients met all inclusion/exclusion criteria, with a median age of 40 and serious injury (average ISS 29, average ICU length of stay 6 days)
  • Functional status at discharge could be assessed in 240 patients, and only 118 could be contacted for long-term followup questions
  • Only 56% of patients with severe TBI had an MRI positive for DAI
  • Functional status was lower on discharge for patients positive for DAI on MRI
  • There was no difference in Glasgow Outcome Score, quality of life, or 3 year survival in patients with MRI evidence of DAI compared to those without

Bottom line: This is a relatively large study, but there are still several weaknesses that could skew the numbers a bit. However, it appears that MRI for prognostication of outcomes in patients with clinical DAI is not very helpful. First, only about half with a clinical picture of DAI showed it on MRI. And sure, MRI may tell us a little bit about their status when they are discharged from the hospital to rehab or transitional care. But is that information very useful? It certainly does not help predict their outcome in the longer term. So why order an expensive and difficult study (think restraints, sedation, lots of pumps and monitors) to tell us what we already know based on our experience with severe TBI?

Reference: Prognosis of diffuse axonal injury with traumatic brain injury. J Trauma 85(1):155-159, 2018

Systemic Air Embolism From Chest Trauma

Systemic air embolism (SAE) is an uncommonly encountered but potentially catastrophic complication that trauma professionals will probably see only once or twice in their career. In a couple of very old papers (30-35 years!), it was said to occur in 4 to 14% of patients with severe lung trauma. The pathognomonic finding is complete cardiovascular collapse shortly after intubation and positive pressure ventilation of a patient with significant chest trauma.

SAE can occur after major blunt or penetrating injury. Normally, pressure in the pulmonary arterial and venous branches of the lungs is higher than that of air in the bronchi. If lung parenchyma is torn by gunshot, stab, or blunt pulmonary laceration, then blood can leak into the smaller airways. Unless a major vessel is torn, the volume lost is not of much consequence. A small amount of hemoptysis may be present.

But if positive pressure is applied to the airways, air may be forced into those vascular structures. If the injury involves a pulmonary vein, the gas bubbles enter the left heart and and then the systemic circulation. Only a cc or two of air in the cerebral circulation or coronary arteries can cause a rapidly fatal condition.

How can a trauma professional suspect that a patient may be susceptible to SAE? Look for evidence of hemoptysis in patients with penetrating chest injury or severe blunt chest trauma. Unfortunately, this occurs in only a few patients and its absence is not helpful.

Always suspect SAE if your patient suffers circulatory collapse or arrest shortly after intubation and positive pressure ventilation. This is especially true in patients who were very stable up until that point. Ultrasound may be used to detect air bubbles in the left heart. Transesophageal echo is even better, but not readily available in the ED.

What can be done if your patient (nearly) arrests after intubation and you suspect SAE? The recommended treatment is single lung ventilation and thoracotomy on the injured side. The injured side is obvious in patients with unilateral penetrating injury, but much more difficult to determine in blunt trauma where either lung may be involved. A quick chest x-ray could be obtained, but may not localize the injured lung.

If the left lung is involved, push the endotracheal tube into the right mainstem bronchus to eliminate the abnormal pressure gradient in the injured lung. If the right lung in injured, a dual lumen endotracheal tube should be inserted for single-lung ventilation. Unfortunately, this requires fiberoptic tools and is not available in the field or most emergency departments.

If single-lung ventilation can be accomplished, this may buy some time to try to resuscitate your patient. A thoracotomy of the injured side can also be carried out to occlude the hilum of the lung in an attempt to stop any further embolism. Initial clamping should be carried out by hand, as using a crushing clamp commits the patient to an emergency pneumonectomy (if they survive beyond this point).

Overall survival is dismal. Old data suggests that more than 80% of blunt trauma victims with SAE die, as well as half of patients with penetrating injury. These numbers are even lower once the patient arrests. The key to survival is avoiding unnecessary intubation in patients with potential SAE, and moving to single-lung ventilation quickly in those who have developed it.

Opioids In Trauma Care: A Suggestion?

In my last post, I reviewed a paper that showed how disorganized we are at responsibly prescribing and providing instructions for use of opioid pain medications. Today, I’ll look at a paper that attempts to provide a bit more concrete guidance on what to do.

This study was performed at Dartmouth, and consisted of a questionnaire sent to a group of patients who had undergone an inpatient general surgical procedure during a 6-month period. These were not trauma procedures, but included gastric bypass, sleeve gastrectomy, lap or open ventral hernia repair, laparoscopic fundoplication, hepatectomy, lap or open pancreatectomy, and lap, open, or robotic colectomy. The authors specifically looked at opioid use before discharge, length of stay and complications, and opioid prescriptions and refills.

After excluding patients who had preop opioid use or abuse, and those who developed postop complications, there were 234 study patients. Here are the factoids:

  • Overall, 85% patients were given opioid prescriptions, and only 38% of the medication prescribed was taken
  • Patients discharged on postop day 1 had different requirements from those who were discharged later, and were studied separately
  • 88% of patients discharged on day 1 had their opioid needs satisfied by 15 pills
  • For patients discharged after day 1, there was a very strong correlation with home needs and the amount of opioid required on the before discharge
  • 41% of patients took no pills the day prior to discharge, 33% took 1 to 3, and 26% took more than 4
  • Proper disposal of unused meds was extremely variable

Based on this information, the authors calculated that 85% of patients’ home opioid use would be met by using the following guideline:

  • If no pills were used the day prior to discharge, none were prescribed
  • If 1-3 were taken, 15 were prescribed
  • If 4 or more were taken, 30 were prescribed

The authors estimated that, if these guidelines had been followed in the patients reviewed, the number of pills prescribed would have decreased by about 40%.

Bottom line: This is an interesting attempt to answer our questions about opioid use after discharge. Of course, there are limitations in extrapolating this to the trauma population. The pain patterns in patients with fractures, chest trauma, or multiple injuries are very different than those with abdominal general surgical procedures,  especially those performed with a laparoscope  or robot. But it does demonstrate some key concepts:

  • It should be possible to systematize discharge prescribing in a significant number of patients
  • We need to provide guidelines and expectations to our patients to help them minimize their use of opioids after discharge
  • We also need to make sure that our patients know what to do if they run out of medication
  • These guidelines must include safe disposal instructions for unused meds so they can’t be diverted for inappropriate use

I’m looking forward to more papers that help quantify these concepts. In the meantime, I guess I’ll hit the drawing board and start sketching out an interim guideline to tide me over until that happens!

Opioids In Trauma Care: Some Data

Yesterday I shared a TED Talk that outlined one person’s experience navigating the system (or lack thereof) for people trying to kick their addiction to medically prescribed narcotics. Today, I’ll share some new data that describes prescribing patterns and patient usage. This information was collected on patients after surgical procedures, not necessarily trauma, so this data may not be completely applicable. But it’s a start.

This paper is from the University of Vermont, and reviewed two datasets regarding opioid prescriptions. The first was a retrospective look at prescriptions written over a one year period after various surgical procedures in either an inpatient or outpatient setting at their center. This was used to design a patient telephone questionnaire containing questions about narcotic prescriptions and how much was used. The survey was administered about 1 week postop for patients having procedures over a 9 month period.

Here are the factoids:

  • Over 10,000 patients were identified in the retrospective arm of the study (!), of which 5100 were orthopedic procedures and 3100 were general surgery
  • 65% of patients were given only narcotic prescriptions on discharge, 24% were give no opioids, 3% were given only a Tramadol prescription, and 8% were given both
  • Residents wrote the vast majority of prescriptions at this academic medical center (63%), with 24% written by advanced practice providers and 13% by the attending surgeon
  • Drugs commonly prescribed in the retrospective data were oxycodone (44%, avg 30 pills), hydromorphone (31%, 25 pills), Tramadol (13%, 50 pills), and hydrocodone (8%, 20 pills)
  • There were considerable variations in prescribing patterns, drugs prescribed, and morphine equivalent doses provided across specialties
  • In the prospective data, the median amount of prescribed narcotic (in morphine equivalents) that was used was only 27%
  • Procedures associated with the highest amount of narcotic use were orthopedic in nature, particularly knee and shoulder operations

Bottom line: There is a huge amount of variability in prescribing patterns at one academic medical center, and this is probably true at most hospitals. There are a number of factors that contribute: the type of prescriber, local customary practices, type of surgery, and many more. Prescribers are not very experienced in predicting patient needs, and patients do not always do a good job communicating their needs to the clinicians.

In the next post, I’ll describe a suggested practice guideline that seeks to bring some sense to this complex topic.

Reference: Post-discharge opioid prescribing and use after common surgical procedures. J Am Coll Surg 226(6):1004-1013, 2018.

Opioids In Trauma Care: Food For Thought

Here’s something I ran across during my reading last week. In the “old days”, I used to encourage my trainees to be generous with pain medicine prescriptions for patients being discharged from the hospital. I would routinely send people home with 60, 75, or more pills. I got a hint of the folly of this just a few years ago when I underwent an outpatient procedure (biceps tendon repair).

The orthopedic surgeon prescribed 15 narcotic pain pills for me to take home. I scoffed at the low number, although I didn’t tell him that. But once I got home and the regional block wore off, how many do you think I took? Exactly one. I (safely) disposed of the rest. This prompted me to start rethinking our role in the opioid problem here in the US.

Tomorrow, I’ll write about a recently published paper and guideline for discharge opioid prescriptions. But today, watch the TED talk embedded below. It reveals the inadequacies within our health care system for those who, one way or another, have developed a dependence on these medications. It was an eye-opener for me.