Category Archives: Equipment

The IVC Filter In Trauma: Why?

December 12, 2016 The Trauma Pro Leave a comment

The inferior vena cava (IVC) filter has been around in one form or another for over 40 years. One would think that we would have figured everything about it out by now. But no! The filter has evolved through a number of iterations and form factors over the years. The existing studies, in general, give us piecemeal information on the utility and safety of the device.

One of the major innovations with this technology came with the development of a removable filter. Take a look at the product below. Note the hook at the top and the (relatively) blunt tips of the feet. This allows a metal sheath to be slipped over the filter while in place in the IVC. The legs collapse, and the entire thing can be removed via the internal jugular vein.

ivc-filter-complications1

The availability of the removable filter led the American College of Chest Physicians to recommend their placement in patients with known pulmonary embolism (PE) or proximal deep venous thrombosis (DVT) in patients with contraindications to anticoagulation. Unfortunately, this has been generalized by some trauma professionals over the years to include any trauma patients at high risk for DVT or PE, but who don’t actually have them yet.

One would think that, given the appearance of one of these filters, they would be protective and clots would get caught up in the legs and be unable to travel to the lungs as a PE. Previous studies have taught us that this is not necessarily the case. Plus, the filter can’t stop clots that originate in the upper extremities from becoming an embolism. And there are quite a few papers that have demonstrated the short- and long-term complications, including clot at and below the filter as well as post-phlebitic syndrome in the lower extremities.

A new study from Boston University reviewed their own experience retrospectively over a 9 year period. This cohort study looked at patients with and without filters, matching them for age, sex, race, and injury severity. The authors specifically looked at mortality, and used four study periods during the 9 year interval.

Here are the factoids:

Over 18,000 patients were admitted during the study period, resulting in 451 with an IVC filter inserted and 1343 matched controls
The patients were followed for an average of 4 years after hospitalization
Mortality was identical between patients with filters vs the matched controls

dvt-study

There was still no difference in mortality, even if the patients with the filter had DVT or PE present when it was inserted
Only 8% ever had their “removable” filter removed (!)

Bottom line: Hopefully, it’s becoming obvious to all that the era of the IVC filter has come and gone. There are many studies that show the downside of placement. And there are several (including this one) that show how forgetful we are about taking them out when no longer needed. And, of course, they are expensive. But the final straw is that they do not seem to protect our patients like we thought (hoped?) they would. It’s time to reconsider those DVT/PE protocols and think really hard about whether we should be inserting IVC filters in trauma patients at all.

Related post:

PE and DVT in trauma

Reference: Association Between Inferior Vena Cava Filter Insertion
in Trauma Patients and In-Hospital and Overall Mortality. JAMA Surg, online ahead of print, September 28, 2016.

Equipment

Why Is My Trauma Patient On Oxygen?

November 29, 2016 The Trauma Pro Leave a comment

How many times has this happened to you? You walk into a young, healthy trauma patient’s room and discover that they have nasal prongs and oxygen in place. Or better yet, these items appear overnight on a patient who never needed them previously. And the reason? The pulse oximeter reading had been “low” at some point.

loc-0424-cs-belding-pet-masks-11-1024x6821

This phenomenon of treating numbers without forethought has been one of my pet peeves for years. Somehow, it is assumed that an oximetry value less than the standard “normal” requires therapy. This is not the case.

In young, healthy people the peripheral oxygen saturation values (O2 sat) are typically 96-100% on room air. As we age, the normal values slowly decline. If we abuse ourselves (smoking, working in toxic environments, etc), lung damage occurs and the values can be significantly lower. Patients with obstructive sleep apnea will have much lower numbers intermittently through the night.

So when does a trauma inpatient actually need supplemental oxygen? Unfortunately, the literature provides little guidance on what “normal” really is in older or less healthy patients. Probably because there is no norm. The key is that the patient must need oxygen therapy.

But how can you tell? Examine them! Talk to them! If the only abnormal finding is patient annoyance due to the persistent beeping of the machine, they don’t need oxygen. If they feel anxious, short of breath, or have new onset tachycardia, they probably do. Saturations in the low 90s or even upper 80s can be normal for the elderly and smokers.

Bottom line: Don’t get into the habit of treating numbers without thinking about them. There are lots of reasons for the oximeter to read artificially low. There are also many reasons for patients to have a low O2 sat reading which is not physiologically significant. So listen, talk, touch and observe. Set the alarm level to 90%, or even lower. And if your patient is comfortable and has no idea that their O2 sat is low, turn off the oxygen and toss the oximeter out the window.

Equipment

What’s The Best Pelvic Binder? Part 2

July 8, 2016 The Trauma Pro Leave a comment

Yesterday, I detailed some pelvic binders commonly available in the US. Today, I’ll go through the (little) science there is regarding which are better than others.

There are a number of factors to consider when choosing one of these products. They are:

Does it work?
Does it hurt or cause skin damage?
Is it easy to use?
How much does it cost?

It’s difficult to determine how well binders work in the live, clinical setting. But biomechanical studies can serve as a surrogate to try to answer this question. One such cadaver study was carried out in the Netherlands a few years ago. They created one of three different fracture types in pelvis specimens. Special locator wires were placed initially so they could measure bone movement before and after binder placement. All three of the previously discussed commercial binders were used.

Here are the factoids:

In fracture patterns that were partially stable or unstable, all binders successfully closed the pelvic ring.
None of the binders caused adverse displacements of fracture fragments.
Pulling force to achieve complete reduction was lowest with the T-POD (40 Newtons) and highest with the SAM pelvic sling (120 Newtons). The SAM sling limits compression to 150 Newtons, which was more than adequate to close the pelvis.

So what about harm? A healthy volunteer study was used to test each binder for tissue pressure levels. The 80 volunteers were outfitted with a pressure sensing mat around their pelvis, and readings were taken with each binder in place.

Here are the additional factoids:

The tissue damage threshold was assumed to be 9.3 kPa sustained for more than 2-3 hours based on the 1994 paper cited below.
All binders exceeded the tissue damage threshold at the greater trochanters and sacrum while lying on a backboard. It was highest with the Pelvic Binder and lowest with the SAM sling.
Pressures over the trochanters decreased significantly after transfer to a hospital bed, but the Pelvic Binder pressures remained at the tissue damage level.
Pressures over the sacrum far exceeded the tissue damage pressure with all binders on a backboard and it remained at or above this level even after transfer to a bed. Once again, the Pelvic Binder pressures were higher. The other splints had similar pressures.

And finally, the price! Although your results may vary due to your buying power, the SAM sling is about $50-$70, the Pelvic Binder $140, and the T-POD $125.

Bottom line: The binder that performed the best (equivalent biomechanical testing, better tissue pressure profile) was the SAM sling. It also happens to be the least expensive, although it takes a little more elbow grease to apply. In my mind, that’s a winning combo. Plus, it’s narrow, which allows easy access to the abdomen and groins for procedures. But remember, whichever one you choose, get them off as soon as possible to avoid skin complications.

References:

Comparison of three different pelvic circumferential compression devices: a biomechanical cadaver study. JBJS 93:230-240, 2011.
Randomised clinical trial comparing pressure characteristics of pelvic circumferential compression devices in healthy volunteers. Injury 42:1020-1026, 2011.
Pressure sores. BMJ 309(6959):853-857, 1994.

Equipment

What’s The Best Pelvic Binder? Part 1

July 7, 2016 The Trauma Pro Leave a comment

Several products for compressing the fractured pelvis are available. They range from free and simple (a sheet), to a bit more complicated and expensive. How to decide which product to use? Today, I’ll discuss the four commonly used products. Tomorrow, I’ll look at the science.

First, let’s dispense with the sheet. Yes, it’s very cheap. But it’s not easy to use correctly, and more difficult to secure. Click here to see my post on its use.

There are three commercial products that are commonly used. First is the Pelvic Binder from the company of the same name (www.pelvicbinder.com). It consists of a relatively wide belt with a tensioning mechanism that attaches to the belt using velcro. One size fits all, so you may have to cut down the belt for smaller patients. Proper tension is gauged by being able to insert two fingers under the binder.

Next is the SAM Pelvic Sling from SAM Medical Products (http://www.sammedical.com). This device is a bit fancier, is slimmer, and the inside is more padded. It uses a belt mechanism to tighten and secure the sling. This mechanism automatically limits the amount of force applied to avoid problems with excessive compression. It comes in three sizes, and the standard size fits 98% of the population, they say.

Finally, there is the T-POD from Pyng Medical (http://www.pyng.com/products/t-podresponder). This one looks similar to the Pelvic Binder in terms of width and tensioning. It is also a cut to fit, one size fits all device. It has a pull tab that uses a pulley system to apply tension. Again, two fingers must be inserted to gauge proper tension.

So those are the choices. Tomorrow, I’ll go over some of the data and pricing so you can make intelligent choices about selecting the right device for you.

Equipment, Surgery

Pelvic Binder Orthosis vs Pelvic External Fixation

July 6, 2016 The Trauma Pro Leave a comment

Yesterday, I wrote about the open book, A-P compression mechanism, pelvic fracture. In the “old” days, the recommended management for an unstable pelvis like these was application of an external fixator. In some textbooks, it was even suggested that this should be done (by orthopedics) in the resuscitation room. High volume trauma centers with ortho residents could actually pull this off, but not many others.

As the idea of pelvic orthotic binders caught on (T-POD, sheeting, etc) and was adopted by prehospital providers, and then trauma teams, the use of initial external fixation dropped off. But the idea that external fixation was the most desirable or most effective lingered on. A study from Memphis finally sheds some light on the answer to this question.

A 10 year retrospective review was carried out on patients presenting with multiple or severe pelvic ring fractures who had early stabilization of the pelvis. Stabilization consisted of external fixation early on, and gradually shifted to pelvic orthotic devices over the study period. They ultimately analyzed outcomes for 93 patients in each treatment group.

The authors found that transfusion needs were dramatically reduced with the orthotic devices (5 units vs 17 units at 24 hours) compared to the orthotics. About a quarter of patients in each group went to angiography, and even in those patients the transfusion need remained lower in the orthotic device group. Hospital length of stay was also significantly shorter in this group (17 vs 24 days). There was no difference in mortality.

Bottom line: Although this is a small, retrospective study it easily showed significant results and will probably never be repeated. Use of a pelvic orthotic device (POD) resulted in less blood replacement and shorter stays in hospital. This technique is simple, cheap and quick, an ideal combination. But does a sheet count as an orthotic device? We don’t know. It’s really cheap, but probably a bit less controlled than a POD. If you have a real POD in your ED or your ambulance, use it. If not, apply the sheet, which will be described tomorrow with other binders.

Tomorrow: what’s the “best” pelvic binder?

Reference: Emergent pelvic fixation in patients with exsanguinating pelvic fractures. JACS 204:935-942, 2007.

Home of the Trauma Professional's Blog