Category Archives: Complications

Should I Apply Compression Devices To Patients With DVT?

December 4, 2020 The Trauma Pro Leave a comment

Everyone knows that venous thromboembolism (VTE) is a potential problem in hospitalized patients, and especially so in trauma patients. Several groups of them are at higher risk by virtue of the particular injuries they have sustained and the activity restriction caused.

Nearly every trauma program uses some form of screening and prophylaxis in an attempt to reduce the occurrence of this problem, which can result in deep venous thrombosis (DVT) and/or pulmonary embolism (PE). Screening looks at patient factors such as age, obesity, previous VTE as well as injury risk factors like spine and pelvic fractures, and decreased mobility.

Based on the screening protocol, prophylaxis may be prescribed depending upon level of VTE risk, which is then balanced with bleeding risk from brain, solid organ, or other injuries. The choices we have are primarily mechanical vs chemical and consist of compression devices (sequential or not) and various heparins.

An age old question surfaced on my own patient rounds recently. If a patient breaks through their prophylaxis and develops DVT, is it safe to apply compression devices to the extremity?

There has always been the fear that doing things that increase flow in the affected extremity may cause clots to dislodge and ultimately cause a PE. Seems logical right? But we know that often, our common sense about things is completely wrong. Couldn’t just moving around cause pieces to break off? A meta-analysis of 13 studies published in 2015 showed that early ambulation was not associated with a higher incidence of new PE. Furthermore, patients who suffered from pain in the affected extremity noted significant improvements with early ambulation.

If ambulation makes the pain better, could the veins be recanalizing more quickly? Another study examined a small group of 72 people with DVT receiving anticoagulants, half of whom were prescribed exercise and compression stockings and the other half stockings only. There was a huge amount of variability in the rates of recanalization, but ultimately there were no significant differences with or without exercise.

So just lying in bed is not good, and exercise/ambulation may actually make people feel better. But interestingly, bedrest alone does not appear to increase the likelihood of PE! It does decrease the risk of developing problems other than the VTE, like pulmonary complications.

But what about compression devices? Common sense would say that you are intermittently increasing pressures in the leg veins, which could dislodge any loose clots and send them flying to the lungs, right?

Unfortunately, I couldn’t find a paper from anyone who had the courage to try this. Or perhaps no institutional review board (IRB) would approve it. But the key fact is that every compression device manufacturer includes existing DVT as a contraindication in their product documentation. They don’t have any literature either, so I assume it’s an attempt to limit litigation, just in case.

Bottom line: Walking provides at least as much muscle compression as compression devices. But the simple truth is that we have no solid research that either supports or condemns the use of active compression devices in patients with known DVT. And we probably won’t, ever.

Compression stockings seem to be safe, but they really don’t do much. They are white, but don’t do much more than contribute to hospital clothing fashion. Since the manufacturers define existing DVT as a contraindication, application of their product would be considered an off-label use. So it looks like we cannot in good faith use these devices in patients with diagnosed DVT.

References:

Bed Rest versus Early Ambulation with Standard Anticoagulation in The Management of Deep Vein Thrombosis: A Meta-Analysis. PLOS One , April 10, 2015, https://doi.org/10.1371/journal.pone.0121388
Bed Rest or Ambulation in the Initial Treatment of Patients With Acute Deep Vein Thrombosis or Pulmonary Embolism: Findings From the RIETE Registry. Chest 127(5):1631-1636, 2005.
Does supervised exercise after deep venous thrombosis improve recanalization of occluded vein segments? A randomized study. J Thrombosis Thrombolysis 23:25-30, 2006.

Complications

NSAIDs And Fracture Healing Revisited

October 23, 2020 The Trauma Pro Leave a comment

Over the years, I’ve commented several times on the “myth” of NSAIDs causing problems with fracture healing. I still hear occasional comments from my orthopedic colleagues cautioning against the use of these drugs in patients who have had fracture repairs.

But is it true? In 2003, several papers brought to light possible interactions between these drugs and fracture healing. Specifically, there were questions about these drugs interfering with the healing process and of increasing the number of delayed unions or nonunions. But once again, how convincing were these papers, really?

It would seem to make sense that NSAIDs could interfere with bone healing. The healing process relies heavily on the regulation of osteoblast and osteoclast function, which itself is regulated by prostaglandins. Since prostaglandins are synthesized by the COX enzymes, COX inhibitors like the NSAIDs should have the potential to impair this process. Indeed, animal studies in rats and rabbits seem to bear this out.

But as we have seen before, good animal studies don’t always translate well into human experience. Although a study from 2005 suggested that NSAID administration in older patients within 90 days of injury had a higher incidence of fracture nonunion, the study design was not a very good one. It was equally likely that patients who required these drugs in this age group may have been at higher risk for nonunion in the first place.

A meta-analysis of human studies was performed in 2011. Out of 558 potential studies, only 5 met criteria review. (This is yet another reminder of the sheer amount of sub-par research out there.) The authors found that short-term use (< 14 days) of normal dose NSAIDS was not associated with non-union. High doses of ketorolac (> 120mg/day) and diclofenac sodium (> 300mg total) did have an association. But remember, this does not show causation. There are many other factors that can impede healing (smoking, diabetes, etc).

A study from 2016 examined the effect of ketorolac administration on fracture healing in patients undergoing repairs of femoral and tibial fractures. It did not find an association between non-union and ketorolac, but did find one with smoking. Unfortunately, the study was small (85 patients given ketorolac, 243 controls without it). It probably does not have the statistical power to detect any difference with the NSAID. A power analysis was not provided in the methods section.

Bottom line: Once again, the animal data is clear and the human data less so. Although there are theoretical concerns about NSAID use and fracture healing, there is still not enough solid risk:benefit information to abandon short-term NSAID use in patients who really need them. NSAIDs can and should be prescribed in patients with short-term needs and simple fractures. But we now have evidence that high-dose NSAIDs may have some impact, so stick to the usual doses for just as long as they are needed for pain management.

References:

Effects of nonsteroidal anti-inflammatory drugs on bone formation and soft-tissue healing. J AM Acad Orthop Surg 12:139-43, 2004.
Effect of COX-2 on fracture-healing in the rat femur. J Bone Joint Surg Am 86:116-123, 2004.
Effects of perioperative anti-inflammatory and immunomodulating therapy on surgical wound healing. Pharmacotherapy 25:1566-1591, 2005.
Pharmacological agents and impairment of fracture healing: what is the evidence? Injury 39:384-394, 2008.
High dose nonsteroidal anti-inflammatory drugs compromise spinal fusion. Can J Anaesth 52:506-512, 2005.
Nonsteroidal Anti-Inflammatory Drugs and Bone-Healing: A Systematic Review of Research Quality. JBJS Rev 4(3), 2016.
High-dose ketorolac affects adult spinal fusion. Spine 36(7):E461-E468, 2011.
Ketorolac administered in the recovery room for acute pain management does not affect healing rates of femoral and tibial fractures. J Orthop Trauma 30(9):479-482, 2016.

Abstracts, Complications

Best Of AAST #9: Blunt Carotid And Vertebral Injuries

September 1, 2020 The Trauma Pro Leave a comment

Blunt carotid and vertebral artery injuries (BCVI) are an under-appreciated problem after blunt trauma. Several screening tools have been published over the years, but they tend to be unevenly applied at individual trauma centers. For an unfortunate few, the only indication of BCVI is a stroke while in hospital.

The overall incidence of BCVI is thought to be small, on the order of 1-2%. But how do we know? Well, the group at Birmingham retrospectively reviewed every CT angiogram (CTA) of they did in a recent two year period. They did this after adopting a policy of screening all their major blunt trauma patients. Each patient chart was also evaluated to see if they met any of the criteria for the three commonly used screening systems.

Here are the factoids:

5,634 of 6,800 blunt trauma patients underwent BCVI screening with CTA of the neck
471 patients (8.4%) were found to have BCVI
Here are the accuracy statistics for the three screening systems

Here are my comments: The authors found that the incidence of BCVI is about 8x what we previously thought. What we don’t know is the percentage of these patients that go on to cause stroke or other neurologic deficits. But this is somewhat frightening.

Even more frightening is that the screening systems that we rely on fare so poorly. The Denver and Modified Memphis criteria have a true positive rate that is the same as a coin toss. And even if the patient meets none of the criteria in any system, about 5% BCVI will sneak through (NPV 95%).

So the question becomes, do we all perform universal screening for blunt trauma? Or do we still use one of the three systems and keep our fingers crossed that the ones we miss will not progress? Or maybe just give everybody an aspirin a day for a while. And still keep our fingers crossed!

Here are some questions for the presenter and authors:

Why did you decide to implement a universal screening protocol in the first place? Bad experience(s)?
Do you have any screening recommendations other than to screen everybody? How do you decide which blunt trauma patients to screen? Every car crash? What level of fall? The devil is in the details!

This is an easy to follow paper with a solid analysis and real world implications. Excellent work!

Abstracts, Complications

Best Of AAST #8: Duplex Screening For DVT

August 31, 2020 The Trauma Pro Leave a comment

To screen on not to screen, that is the question. If you do more testing, you will find more cases. But does it make a difference clinically? Sounds like some of the questions coming up in our current discussion of the Coronavirus. But that’s what we really need to know.

The group at Intermountain Medical Center in Salt Lake City performed a 2 ½ year randomized, prospective study of screening duplex ultrasound of the lower extremities vs no screening study. They used the Risk Assessment Profile (RAP) developed by Greenfield, first published in 2000. Any patient at moderate or higher risk for DVT (RAP score >5) was enrolled in the study. They were randomized into two groups: a screening group who received duplex scans on days 1, 3, 7, and then weekly, and a “no routine screening” group. All patients received chemoprophylaxis per the trauma service’s existing protocol.

The RAP score is a 17 factor scale that assigns a specific number of points based on underlying medical conditions, iatrogenic factors like central lines or transfusions, injury-related factors, and age.

Here are the factoids:

A total of 3,236 trauma patients were identified, and the 1,989 who were at moderate or higher risk for DVT were evenly randomized to screening vs no screening
There were no differences in age, sex, BMI, mechanism, ISS, or length of stay between the two groups
The incidence of DVT was 15% in the screened group vs 1.7% in the no screening group

The authors concluded that screening diagnoses more DVT, most of which is below the knee. And they also noted that screening identified DVT more often than clinical exam alone, but does not result in fewer PE or deaths. They suggest that more work needs to be done to identify exactly who benefits from duplex screening the most.

Here are my comments:

Finally, an easy to follow and well-designed study! But I think some of the results may be missing from the abstract. That section cuts off in the middle of some of the statistics, and there is no mention of the clot location or PE/mortality rates mentioned in the conclusion.

I also worry that a thousand patients in each group may not be enough. We are working with low incidence end points like PE and death, and this is an association study with many potential confounders/factors that may not have been recorded. I generally like to see the ability to detect a minimum of a 2x effect. So if the incidence of PE is 1.5%, I like to see the ability to detect a difference if the other group is 3%.

And speaking of study size. The RAP score was first described in 1997 and was a pilot study. They drew their conclusions from only 53 patients, and the only risk factor that they could show that was a statistically significant predictor of DVT was age. They concluded that surveillance of patients with RAP > 5 was warranted. This abstract builds upon this work, but is trying to say that maybe we don’t need to do duplex scans.

Here are my questions for the presenter and authors:

Is there some text missing from the end of the results section of the abstract? It seems to end unexpectedly, and some things are mentioned in the conclusions that are not in the results.
Why did you choose the RAP score? There are other risk assessment tools available out there. What is so special about RAP?
Is your sample size large enough to detect differences in incidence of PE or death? My back of the envelope calculations suggest at least 1,500 patients would be needed in each group.
How long did you follow patients to determine if they had PE or death? Until they were discharged? Later than that? This makes a big difference in the eventual incidence of these outcomes.
Based on what you found, is there any value to treating asymptomatic proximal DVT? It sounds like you are saying that screening is not needed at all because PE and death are the same. Isn’t there value in treating proximal DVT if you find it?

This abstract certainly got me thinking! I am looking forward to the presentation and discussion of this abstract!

Reference: Head in the sand? The value of routine duplex ultrasound screening for venous thromboembolism in the trauma patient: a randomized Vanguard trial. AAST 2020, Oral Abstract #16.

Complications

Early Antibiotic Administration In Open Fractures

June 15, 2020 The Trauma Pro Leave a comment

Recommendations for open fracture management has evolved over the past 20 years. The old-timey rule used to be: all open fractures need to be treated within 8 hours. This treatment could be washout and ORIF, washout and external fixation, or just washout alone. The washout was the constant across all types of management.

Then the orthopedics literature began to suggest that “lesser” fractures (Gustilo I – II) could go a bit longer. Some centers extended their required time to washout up to 12 or even 16 hours. Subsequently, the value of early IV antibiotics was recognized, and the time to washout started to change again.

Now, we have recommendations for early IV antibiotics competing with the old recommendations for prompt washout. Who is winning?

There are two recent papers that seem to provide conflicting recommendations regarding antibiotics. The first is in process for publication by the ortho group at San Francisco General Hospital. They studied 230 open fracture patients at their Level I Trauma center over a five-year period. They monitored for surgical site infection that occurred during the first 90 days after injury.

Here are the factoids:

It took 450 consecutive patients to find the 230 study patients due to these exclusion criteria: missing documentation of antibiotic administration, delayed presentation, and loss to followup
There were 169 Gustilo Type I or II fractures and 61 Type III fractures
They noted a trend (p = 0.053) toward infection in patients who had antibiotic administration an average of 83 minutes after arrival vs those who received them within one hour
Patients who received their antibiotics 2 hours after arrival had a 2.4x increase in likelihood for infection within 90 days

But there was another paper published in the same journal this year that shows the opposite result. This one is from the University of Bristol in the UK. This one reviewed only Gustilo Type III fractures and observed changes in the deep infection rate, before and after the National Health Service guidance on antibiotic administration changed from within three hours to one hour post-injury.

Some more factoids for you:

A total of 176 patients were identified at a single center, and only 152 were left after the usual exclusions
Average time to antibiotic administration decreased from 180 minutes to 160 minutes after the new guidance was issued (60 minutes(!))
Only 12 patients developed deep infections with a median followup of 26 months
On regression analysis, no obvious factors for increased risk were identified

Bottom line: So what gives? Two different answers: antibiotics given after 2 hours is associated with an increased risk of infection, vs no difference?

No, not really. Talk about apples to bananas. The first study looks at all open fractures, not just the most severe. It does not really define “surgical site infection,” so can we assume it was any infection? We don’t know. The second study looked only at deep infections.

The sample sizes are marginal in both studies, although the first was able to show a significant result despite this. And, of course, these are association studies, so other factors could be at play to manifest an infection or not. Both groups showed an 8-11% infection rate of some kind in their Gustilo Grade III fractures.

But the biggest issue with the second study is that, despite guidance that antibiotics should be given within an hour, the average time decreased from 3 hours to only 2:40. This is still beyond the two hour threshold to higher infection rates suggested in the first paper.

So what do I make of all of this? The UK paper is lacking the power and enough of a treatment change to be taken seriously. The San Francisco paper shows borderline results with a 2.4x increase in all infections if antibiotics are given after 2 hours.

So until we have better data and larger series, 1 hour antibiotic administration seems like a painless way to decrease the likelihood of an infection. But whether that can safely delay the time to washout remains to be seen.

References:

Delay of Antibiotic Administration Greater than 2 Hours Predicts Surgical Site Infection in Open Fractures. Injury, in press, May 29, 2020.
Time to intravenous antibiotic administration (TIbiA) in severe open tibial fractures: Impact of change to national guidance. Injury 51:1086-1090, 2020.

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