All posts by The Trauma Pro

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Best Of EAST #10: (F)utility Of ICP Monitoring In Geriatric Patients?

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Patients with severe TBI are typically managed using staged protocols based on the Brain Trauma Foundation (BTF) guidelines for ICP monitoring. There have been a number of papers over the past six years that question the utility of ICP monitoring, at least using the procedures in the BTF guidelines.  Most of these studies do not specifically break out elderly patients.

The group at the Westchester Medical Center in NY used the TQIP database to review the impact of ICP monitoring for severe TBI in patients > 65 years old. They performed a four year database study on these patients with an isolated head injury (no other body regions with AIS > 2), initial GCS < 8, and a length of stay > 24 hours. The examined the presence or absence of an ICP monitor, AIS head score, GCS, and a number of outcome measures.

Here are the factoids:

  • A total of 4,433 patients met the above criteria, and 17% had an ICP monitor placed
  • After propensity matching for those with and without an ICP monitor, mortality was nearly identical in both groups at 49%
  • ICU length of stay, hospital length of stay, and ventilator days were significantly longer in the monitor group

The authors concluded that ICP monitoring in this elderly group of patients did not improve survival and increased length of time in the ICU, hospital, and on the ventilator. The recommend that the current guidelines be improved to recognize these facts.

Bottom line: This is a nice, simple study that sought to answer just a few nice, simple questions. The mortality results are convincingly equal between the groups with and without an ICP monitor. The lengths of stay and ventilator days are statistically significantly longer with p values < 0.001. However, the actual numbers are not provided. I have seen many studies where statistically different numbers are not clinically relevant.

There are a number of papers that have come to similar conclusion on other or broader groups of TBI patients. Although we have specific guidelines on who gets a monitor and what we do with the numbers, there is growing doubt that their use actually helps. Perhaps it is time for us to review the data and make appropriate revisions!

Here are my questions for the authors and presenter:

  • Tell us about your propensity score matching. This will help us understand how similar the patient groups really were, with the exception of their ICP monitors.
  • Please provide the actual numbers for your lengths of stay and ventilator days. We need to be sure these are clinically and/or financially significant.
  • Have the results of this work prompted you to rework your own practice guidelines for treatment of severe TBI? I’m always interested if the group feels strongly enough about their work that they would consider changing their practice based on it.

Reference: ROLE OF ICP MONITORING IN GERIATRIC TRAUMA PATIENTS. EAST 35th ASA, oral abstract #33.

 

Head, Imaging

Best Of EAST #9: Routine Repeat Head CT For TBI Patients On Antithrombotic Agents

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The data we use as guidance for repeat head CT in elderly patients who sustain mild TBI while taking antithrombotic therapy remains limited. There is a slowly growing consensus that the need is limited, but there is still a very wide variation in practice patterns.

The group at HCA Healthcare Nashville collected data from 24 system hospitals on this very specific cohort of patients: elderly (age > 55), head trauma with GCS 14-15, an initial head CT, and no other injuries with AIS > 2. They divided these patients into two groups based on whether they were currently taking antithrombotic (AT) therapy. Rate of delayed intracranial hemorrhage (ICH), need for neurosurgical intervention, and mortality were compared.

Here are the factoids:

  • About 3,000 patients were enrolled and only 10% had a repeat head CT
  • Of those who were rescanned, 10% of patients on meds had a new ICH vs 6% in those not taking meds (not statistically significant)
  • Extrapolating those numbers to all patients, the rate of delayed ICH would be 0.7% in patients not taking AT vs 1.0% for those who were (also not significant)
  • Mortality attributable to a head bleed occurred in only one patient who was made comfort care
  • There were no neurosurgical procedures performed in either group

The authors concluded that this specific subset of patients has a very low rate of delayed ICH, and that there are minimal clinical consequences in those that do. They do not support repeat head CT.

Bottom line: This abstract adds to the growing body of literature that shows little benefit to repeat head CT scan after a negative initial study, even if the patient is on blood thinners. Many previous studies involve only a single center and/or have smaller numbers. This one is larger because of the size of the HCA trauma system, and answers a simple set of questions on a limited subgroup of patients: elderly, mild TBI, with limited other injuries.

My back of the envelope power calculations show the authors may be a little short of the number of subjects to be able to show that the difference in the number of delayed ICH (0.7% vs 1.0%) is statistically significant. But the numbers are close enough and the p value so large (0.3) that they are probably right. This is completely offset by the absence of necessary neurosurgical interventions and the single attributable death.

Many trauma centers, including my own, have adopted a “no repeat scan” policy after a negative initial scan, even on thinners. In fact, unless the patient has some other injury that requires admission, they are discharged home with a responsible adult.

Here are my questions for the authors and presenter:

  • Did you do any type of power analysis to determine if the large number of patients included was actually large enough?
  • The term “antithrombotic therapy” is used broadly; which agents were considered in this category? Traditional warfarin therapy? Aspirin and other antiplatelet agents? DOACS?
  • Have you changed your system guidelines to reflect your work?

This is important and practical work! I’m looking forward to hearing all the details.

Reference: ROUTINE REPEAT BRAIN CT SCANNING IS UNNECESSARY IN OLDER PATIENTS WITH GCS 14-15 AND A NORMAL INITIAL BRAIN CT SCAN REGARDLESS OF PREINJURY ANTITHROMBOTIC USE: A MULTICENTER STUDY OF 3033 PATIENTS. EAST 35th ASA, oral abstract #31.

Complications, Imaging

Best Of EAST #8: Timing Of Reimaging For BCVI

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There are still many questions regarding optimal management of blunt carotid and vertebral arterial injury (BCVI). We know that they may ultimately result in a stroke. And we kind of know how to manage them to try to avoid this. We also know that the grade may change over time, and many vascular surgeons recommend re-imaging at some point.

But when? There are still many questions. A multi-center trial has been collecting observational data on this issue since 2018. The group reviewed three years of data to examine imaging characteristics and stroke rate during the study period.

Here are the factoids:

  • A total of 739 cases were identified at 16 trauma centers
  • The median number of imaging studies was 2, with a range of 1-9 (!). Two thirds received only one study.
  • Injury grade distribution was as follows:
    • Grade 1 – 42%
    • Grade 2 – 30%
    • Grade 3 – 10%
    • Grade 4 – 18%
    • Grade 5 – <1%
  • About 30% changed in grade during the hospitalization, with 7% increasing and 24% decreasing.
  • Average time to change in grade was 7 days
  • Nearly 75% of those that decreased actually resolved. All of the grade 1 lesions resolved.
  • Stroke tended to occur after about one day after admission, although the grade 1 lesions took longer at 4 days
  • Strokes occurred much earlier than grade change

The authors concluded that there should be further investigation about the utility of serial imaging for stroke prevention.

Bottom line: This is basically a “how we did it” study to tease out data on imaging and stroke after BCVI. It’s clear that there is no consensus across trauma centers regarding if and when repeat imaging is done. And it’s not really possible to make any recommendations about repeat imaging based on this study.

However, it does uncover one important fact. It takes a week for the injury grade on CT to change, but strokes occur much earlier and usually within 24 hours! This is important because it makes it clear that it’s crucial to actually make the diagnosis early. Average stroke occurrence was 9% overall. Grade 1 injuries had only a 3% rate, but grades 2-4 were in the 12-15% range. Grade 5 had a 50% stroke rate!

These facts reinforce the importance of identifying as many of these BCVI as possible during the initial evaluation. The abstract I reviewed yesterday confirmed that the existing screening criteria (Memphis, Denver) will miss too many. More liberal imaging is probably indicated. If you missed the post, click here to view it in a new window.

Here are my comments for the authors and presenter:

  • The “change in BCVI grade over time” charts in the abstract are not readable. Please provide clear images during your presentation and explain what they mean. I was confused!
  • Based on your data, do you have any recommendations regarding the utility of re-imaging? Is it necessary in the same hospitalization at all? These patients will receive treatment anyway, and it doesn’t appear to have any impact on stroke rate.
  • Do you have any recommendations regarding the (f)utility of existing screening systems given the early occurrences of stroke in the study? Are you a fan of using energy / mechanism rather than a bullet list of criteria?

This is important work and I can’t wait to look at the data up close.

Reference: BLUNT CEREBROVASCULAR INJURIES: TIMING OF CHANGES TO INJURY GRADE AND STROKE FORMATION ON SERIAL IMAGING FROM AN EAST MULTI-INSTITUTIONAL TRIAL. EAST 35th ASA, oral abstract #34.

Complications, Imaging

Best Of EAST #7: Routine Screening vs Denver Criteria For BCVI

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Currently, blunt carotid and vertebral artery injury (BCVI) is diagnosed using CT angiography of the great vessels and neck. This study is typically ordered when there is some degree of clinical suspicion based on the application of an established screening system. There are currently two such systems in use, Denver and Memphis.

I dedicated a week to BCVI earlier in the year. If you’d like to read the series, click here.

Both screening systems have been updated over the years. There is now a modified Memphis and an expanded Denver system. The reason for the modifications is simple: some patients were not flagged as at risk by the original versions of the systems. Does this mean we should screen more, or even screen everybody?

To answer this question, it’s important to have an idea of the number of patients who actually sustain the injury. This means having a liberal screening policy in place in the first place. The trauma group at Ascension St. Vincent Hospital in Indianapolis liberalized their criteria in 2012 and first published their experience in 2015. In this abstract, they examined their experience in screening all high-energy patients and reviewing how many patients would have been screened using the expanded Denver criteria.

Here are the factoids:

  • This is a single-center, retrospective study carried out over 5.5 years
  • A total of about 17,000 blunt trauma patients were seen, and about 30% underwent CTA neck for BCVI screening
  • About 1% of total patients screened were found to have BCVI, which was about 3% of those who underwent CTA
  • Sixteen percent of patients who actually had BCVI did NOT meet any of the expanded Denver criteria
  • Ten percent of patients with grades III-V injury did not meet any of the criteria

The authors concluded that using the expanded Denver criteria alone will result in missed injuries and that liberalized screen should be considered to decrease risk.

Bottom line: Once again, this is a paper that conforms to my own bias and experience, so I have to work to be critical of it. We have seen delayed diagnoses of this injury at our center using the standard criteria. For that reason, we recently implemented a guideline to add CTA neck on any patient with a mechanism sufficient to warrant CTA chest (we are not automatic pan-scanners).

This is a straightforward descriptive study at a center that has had a liberal BCVI screening guideline for nearly a decade. The only opportunity for bias lies in the specifics of the screening criteria. In St. Vincent’s case, it is simple: any patient with a mechanism sufficient to require CT cervical spine or chest received CTA neck as well.

I would argue that this might be a bit too liberal. There are many elderly patients who fall that require cervical spine CT, but the mechanism should be insufficient to sustain a BCVI. It can be an add-on study if fracture patterns are seen that fall within the Denver or Memphis criteria.

Here are my questions for the authors and presenter:

  • Why choose the Denver criteria? Why not look at Memphis, too? I’m sure you will find similar issues.
  • Did you analyze your elderly falls patients who got their CTA based on your cervical CT criterion? It seems like this could result in substantial overtriage. Did you actually detect any BCVI in this group if they didn’t have one of the classic fracture patterns?

This is an important abstract, and I’m looking forward to hearing all the specifics! It looks like it may be time to seriously consider the energy of the mechanism, if not ditch the criteria altogether.

Reference: ROUTINE CT SCREENING FOR BLUNT CEREBROVASCULAR INJURY IDENTIFIES INJURIES MISSED BY CLINICAL RISK FACTORS. EAST 35th ASA, oral abstract #35.

Complications, Pharmacy

Best Of EAST #6: How Long Does Risk For VTE Last After Spine Fracture?

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Most trauma centers use an existing venous thromboembolism (VTE) guideline or have developed their own injury-specific one. These include risk factors, contraindications, specific agent, and dosing recommendations. But one thing most do not include is duration of prophylaxis!

The length of time a patient is at risk for VTE is not well delineated yet. The group at the University of Arizona decided to tackle this program using the National Readmission Database. This dataset is a comprehensive resource for critically analyzing patients who are discharged and readmitted, even for multiple occurrences. It covers 30 states and almost two thirds of the population.

The authors focused on VTE occurring during the first six months after injury. Patients who died on the initial admission, were taking anticoagulants, had spinal surgery, or sustained a spinal cord injury were excluded. Over 41,000 records from the year 2017 met these criteria.

Here are the factoids:

  • The average age was 61, which shows the skew toward the elderly with these injuries
  • Spine areas injured were cervical in 20%, thoracic in 19%, lumbar in 29%, sacrococcygeal in 11%, and multiple levels in 21%.
  • During the initial admission, 1.5% developed VTE: 0.9% were DVT and 0.7% were PE
  • Within 1 month of discharge, 0.6% of patients were readmitted for VTE: 0.4% DVT and 0.3% PE
  • In the first 6 months, 1.2% had been readmitted: 0.9% DVT and 0.6% PE
  • Mortality in the first 6 months was 6.7%
  • Factors associated with readmission for VTE included older age, discharge to a skilled nursing facility, rehab center, or care facility

The authors concluded that VTE risk remains high up to 6 months after conservatively managed spinal fractures. They recommend further study to determine the ideal prophylactic agent and duration.

Bottom line: This is a creative way of examining a difficult problem. We know that VTE risk does not stop when our patient is discharged. This is one of the few ways to get a sense of readmissions, even if it is not to the same hospital. And remember, this is an underestimate because it’s possible for a patient living near a state border to be re-hospitalized in a state not in this database.

This study might prompt us to prescribe up to six months of prophylaxis, particularly in seniors who are discharged to other care facilities.

Here are my questions for the author and presenter:

  • Is there any way to extrapolate your data to the entire population of the US, or to compensate for the “readmission over state lines” problem?
  • Is the odds ratio of 1.01 for risk of VTE in the elderly age group significant in any way? It seems like a very low number that would be easily overwhelmed by the “noise” in this data set.
  • Is the mortality number for all causes, or just VTE?

This is an intriguing study, and one that should influence the VTE guidelines in place at many trauma centers!

Reference: THE LONG-TERM RISKS OF VENOUS THROMBOEMBOLISM AFTER NON-OPERATIVELY MANAGED SPINAL FRACTURE. EAST 35th ASA, oral abstract #28.