All posts by The Trauma Pro

General

Animals vs Cars: What To Do

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This is a bad time of year in much of the United States for striking animals on the road. In my part of the country, the deer are out in full force. Car vs animal can be challenging, and motorcycle vs animal is frequently deadly. What can our patients do to protect themselves?

  • Be especially vigilant when driving for the first few hours after sunset and just before sunrise. More animal activity occurs during these hours.
  • If one animal is spotted, look out for others.
  • Drive with high beams on as much as possible. In many animals, this will show reflections from their eyes. Some large animals, such as moose, don’t have glowing eyes.
  • Always where a seat belt in case an impact does occur.
  • If an animal is spotted, slow down quickly and blow the horn.

Most important! NEVER swerve or attempt to quickly change direction. This is one of the most common errors that results in serious injury or death. The driver swerves to avoid the animal and begins to leave the roadway. They then over-correct in the opposite direction, triggering a rollover. Always make gentle corrections, staying in the same lane.

For small animals, slowly adjust the steering wheel to straddle them with the wheels. For larger ones, try to plan the impact so it is in front of the unoccupied front passenger seat. If the seat is occupied, plan the strike in the middle of the hood. The idea is to keep the car occupants safe, but to assist with natural selection and remove the animal from the gene pool.

Abdomen

Do We Really Need To Admit Children With Low-Grade Solid Organ Injury?

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Over the years, we have slowly gotten wiser about solid organ injuries (SOI). Way back when, before CT and ultrasound, if there was a suspicion a patient had such an injury you were off to the operating room. We learned (from children, I might add) that these injuries, especially the minor ones, were not such a big deal.

However, we routinely admit adults and children with solid organ injury of any grade. Many centers have streamlined their practice guidelines so that these patients don’t spend very long in the hospital, but most are still admitted. A number of researchers from Level I pediatric centers in the US got together to see if this is really necessary.

They combed through 10 years worth of TQIP data for outcomes and timing of intervention in children with low-grade (grades 1 and 2) solid organ injury age 16 or less. Children with “trivial” extra-abdominal injuries were included to make the conclusions more generalizable.  Penetrating injuries and burns were excluded, as were those with “risk of hemorrhage” or need for abdominal exploration for reasons other than the SOI. The risk of hemorrhage was defined as a pre-existing condition or other injury that made it more likely that a transfusion might be necessary for other causes.

Here are the factoids:

  • A total of 1,019 children with low-grade SOI (liver, kidney, or spleen) were enrolled in the study, and 97% were admitted
  • There was an even distribution across age groups. Many studies over-represent teenagers; this was not the case here.
  • Median LOS was 2 days, and a quarter were admitted to the ICU
  • Only 1.7% required an intervention, usually on the first hospital day (transfusion, angiography, or laparotomy)
  • Pediatric trauma centers did not perform any of the 9 angiographic procedures, and they only performed 1 laparotomy of the 4 reported

The authors concluded that practice guidelines should be developed for adult centers caring for children to decrease the number of possibly unnecessary interventions, and that it may be feasible to manage many children with low-grade SOI outside of the hospital.

Bottom line: This is an intriguing study. The admission length and silly restrictions like bed rest, NPO, and multiple lab draws are finally approaching their end. Although this paper does have the usual limitations of using a large retrospective database, it was nicely done and thoughtfully analyzed. 

It confirms that adverse events in this population are very uncommon, and that adult centers are still too aggressive in treating children like adults. The recommendation regarding practice guidelines is very poignant and this should be a high priority.

Individual centers should determine if they have the infrastructure to identify low-risk children who have reliable families and live in proximity to a hospital with a general surgeon, or better yet, near a trauma center. Hopefully this study will help accelerate the adoption of such guidelines and practices, moving treatment for many children to the outpatient setting.

Reference: Hospital-based intervention is rarely needed for children with low-grade blunt abdominal solid organ injury: An analysis of the Trauma Quality Improvement Program registry. JTrauma 91(4):590-598, 2021.

Hospital

Adding A Hospitalist To The Trauma Service

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Hospitals are increasingly relying on a hospitalist model to deliver care to inpatients on medical services. These medical generalists are usually trained in general internal medicine, family medicine, or pediatrics and provide general hospital-based care. Specialists, both medical and surgical, may be consulted when needed.

In most higher level trauma centers in the US (I and II), major trauma patients are admitted to a surgical service (Trauma), and other nonsurgical specialists are consulted based on the needs of the patients and the competencies of the surgeons managing the patients. As our population ages, more and more elderly patients are admitted for traumatic injury, with more and more complex medical comorbidities.

Is there a benefit to adding medical expertise to the trauma service? A few studies have now looked at this, and I will review them over the next few days. The Level I trauma center at Christiana Care in Wilmington, Delaware embedded a trauma hospitalist (THOSP) in the trauma service. They participated in the care of trauma patients with coronary artery disease, CHF, arrhythmias, chronic diseases of the lung or kidneys, stroke, diabetes, or those taking anticoagulants.

The THOSP was consulted on appropriate patients upon admission, or during admission if one of the conditions was discovered later. They attended morning and afternoon sign-outs, and weekly multidisciplinary rounds. A total of 566 patients with hospitalist involvement were matched to controls, and ultimately 469 patients were studied.

Here are the factoids:

  • Addition of the THOSP resulted in a 1 day increase in hospital length of stay
  • Trauma readmissions decreased significantly from 2.4% to 0.6%
  • The number of upgrades to ICU status doubled, but ICU LOS remained the same
  • Mortality decreased significantly from 2.9% to 0.4%
  • The incidence of renal failure decreased significantly
  • Non-significant decreases in cardiovascular events, DVT/PE and sepsis were also noted
  • There was no difference in the number of medical specialty consults placed (cardiology, endocrinology, neurology, nephrology)

Bottom line: This paper shows some positive impact, along with some puzzling mixed results. The decrease in mortality and many complications is very positive. Was the increase in ICU transfers due to a different care philosophy in medical vs surgical personnel? And the failure to decrease the number of specialty consults was very disappointing to me. I would expect that having additional medical expertise on the team should make a difference there.

Was the THOSP really “embedded” if they were not involved in the regular daily rounds? In this case, they were present only for handoffs and for weekly multidisciplinary rounds. I believe that having them on the rounding team daily would be of huge benefit, allowing the surgeons and hospitalists to learn from each other. Plus, there should be a benefit to the residents in a Level I center, helping them broaden their ability to care for these complicated patients.

Reference: Embedding a trauma hospitalist in the trauma service reduces mortality and 30-day trauma-related readmissions. J Trauma 81(1):178-183, 2016.

Head, Prehospital

Hitting The Brakes May Increase Intracranial Pressure During The Ambulance Ride!

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One of the most common injuries encountered by trauma professionals is blunt head trauma, and it’s one of the leading causes of death in young people. Keeping the level of intracranial pressure (ICP) within a specified range is one of the basic tenets of critical neurotrauma care in these patients. Most trauma centers have sophisticated algorithms that provide treatment guidance for various levels of ICP or cerebral perfusion.

The vast majority of patients with severe head injuries are transported to the hospital in some type of ambulance. Obviously, the exact ICP level is not known during transport because no monitoring device is present. We can sometimes infer that ICP is elevated if the patient has a Cushing response (wide pulse pressure and bradycardia) or unequal pupils. But for the most part, we assume that ICP is in a steady state during the ambulance ride.

But here’s something I never considered before: can ambulance acceleration or deceleration change the ICP through shifting of the brain or cerebrospinal fluid?

Patients are generally loaded into ambulances head-first, with their feet toward the back door. Frequently, they must be positioned supine in consideration of possible thoracic or lumbar spine injury. This position itself may lead to an increase in ICP. But what happens when the ambulance is hitting the brakes as it approaches a light or stop sign? As the patient’s weight shifts toward the top of the head, so does the CSF, spinal cord, and brain. Couldn’t this, too, increase ICP?

The anesthesiology group at the Erasmus Medical Center in Rotterdam, Holland performed a very novel study to assess this very thing. They recruited twenty participants in whom they evaluated ICP in various positions during acceleration and deceleration.
No, the subjects did not have an actual invasive ICP monitor inserted.

The authors used a novel way to infer pressures: optic nerve sheath diameter (ONSD). The optic nerves are direct extensions of the brain, and CSF travels freely in the nerve sheath. As ICP rises, the diameter of the nerve sheath increases. The subjects were fitted with a special helmet with two devices mounted on it. The first was a 7.5 Mhz ultra-sound probe focused on the back of the eye. The second was an arm with an orange dot on the end. This was adjusted so that the ultrasound probe was pointing at the optic nerve sheath when the other eye was focused on the dot. Subjects just watched the dot and measurements streamed in! Crude but very effective.

Baseline measurements were taken without acceleration or deceleration, then repeated when accelerating to 50 km/hr and decelerating to a stop.

Here are the factoids:

  • A total of 20 subjects were tested, and their oxygen saturation, blood pressure, and pulse were identical pre- and post-test
  • Baseline ONSD was about 5mm; a relevant change in diameter was determined to be more than 0.2 mm
  • Lying supine, the ONSD in nearly all subjects increased from an average 4.8 to 6.0 mm during deceleration
  • With the head raised to 30º, most values remained steady (from 4.8 to 4.9 mm) during deceleration

The left block shows the increase in size of the optic disk with braking while supine. The right one demonstrates that this effect is neutralized by elevating the head 30º.

Bottom line: This is a small, simple, and creative study, yet the results are very interesting! It is clear that optic nerve sheath diameter increases significantly during deceleration in patients who are supine. And this effect is eliminated if the head of bed is elevated 30º.

Unfortunately, we have no idea how the change in ONSD corresponds to absolute values of, or relative increases in, ICP. Does a change of 1.2mm indicate a 5 torr increase in ICP? A 5% increase? Is it proportional to the absolute ICP? We just don’t know.

But the data is clear that a measurable change does occur. Until better data is available, it may be desirable to transport patients with serious head injuries with the head elevated to 30º if there are no concerns for lower spine injury. Or failing that, make sure the driver does not have a lead foot!

Reference: Ambulance deceleration causes increased intra cranial pressure in supine position: a prospective observational prove of principle study. Scand J Trauma Open Access 29:87, 2021.

Complications

TXA, Thromboembolic Events, And Mortality

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I’ve visited several hundred trauma centers over the past 25 years, and recently I’ve begun to appreciate that there are two camps  when it comes to the use of tranexamic acid: the TXA believers and the TXA hesitant.

There have been a number of large studies that seem to suggest a benefit with respect to survival from major hemorrhage, particularly if given soon after injury (CRASH-2, MATTERs). This drug is dirt cheap and has been around a long time, so it has a clearly defined risk profile.

However, many of those hesitant to use it point to the possibility of thromboembolic events that have been sporadically reported. Several years ago, I did my own literature review and found that the number of thrombotic events from TXA was nearly identical to that of transfusing plasma.

JAMA Surgery just published a large systematic review, meta-analysis, and meta-regression that sought to examine the association between thromboembolic events (TE) in patients of any age and involving all medical disciplines, not just trauma.

The anesthesia group at the University Hospital Frankfurt in German did a systematic search of the Cochrane Central Register of Controlled Trials, as well as MEDLINE, for randomized controlled trials involving TXA. They covered all published studies through December 2020.

The authors adhered to standard guidelines for conducting reviews and meta-analysis (PRISMA). They specifically searched for outcomes involving TEs, such as venous thromboembolism, myocardial infarction or ischemia, limb ischemia, mesenteric thrombosis, and hepatic artery thrombosis. They also tallied the overall mortality, bleeding mortality, and non-bleeding mortality.

Here are the factoids:

  • A total of 216 eligible trials were identified that included over 125,000 patients (!)
  • Total TEs in the TXA group were 1,020 (2.1%) vs 900 (2.0%) in the control group
  • Studies at lowest risk for selection bias showed similar results

Bottom line: The authors concluded that IV TXA, irrespective of the dose, does not increase the risk of thromboembolic events. Period.

Hopefully, this is the final study needed to convince the TXA hesitant that it is safe to administer. They may still argue the efficacy, but at less than $100 per vial it is becoming impossible to ignore.

Reference: Association of Intravenous Tranexamic Acid With Thromboembolic Events and Mortality A Systematic Review, Meta-analysis, and Meta-regression. JAMA Surgery 156(6):3210884, 2021.