Category Archives: Prehospital

Trauma Patient Mortality In ALS vs BLS Prehospital Transport

There is a presumption that more education and attainment of more advanced skills lead to greater expertise in just about any field. The same argument holds true for prehospital provider training. Training to be an ALS provider (advanced EMT or paramedic) should add extra value in patient care over and above BLS training (emergency medical responder or EMT).

One way to measure that added value is by comparing trauma patient mortality across those levels of training. Paradoxically, many studies have shown either no benefit or an actual increase in mortality. How does this make sense? Some have speculated that the advanced training leads providers to “stay and play” and use the skills that they have learned. Other possibilities include study design issues (low subject numbers) or failure to consider some unknown variables that impact mortality.

A paper published just this month from Hennepin County Medical Center in Minneapolis examined this phenomenon more closely to determine whether this effect is real or whether other factors are involved. They performed a retrospective study of a nationwide database of prehospital ground transports, selecting records that involved only injured patients. Only patients with documented ALS or BLS providers who were transported to Level I or II trauma centers were included. The ratio of ALS to BLS transports was about 15:1, so propensity matching was performed to create equal groups for comparison.

Here are the factoids:

  • A total of 1,154 matched pairs were available for study,
  • Overall, mortality was significantly lower in the patient group transported by ALS providers
  • Mortality was also significantly lower in older patients (age > 50) and those with mechanisms other than falls
  • There was no statistical difference in patients with falls or in those with prolonged transport times

The authors concluded that more advanced prehospital training is associated with survival. They recognized that there are many factors in the care process that are not captured in the usual databases that may have an impact on survival.

Bottom line: This study was nicely designed and well-executed. It has the largest subject pool of any of the papers published on this topic. It shows that survival is higher when ALS providers transport the patient. But keep in mind that it does not show causality. We don’t know exactly why this is true. It could certainly be the advanced education, but there is still the possibility of other variables that we either haven’t thought of or are not captured in the available databases. But until we know better, we should encourage all EMS providers to up their game, and skill level! 

Reference: Emergency medical services level of training is associated with mortality in trauma patients: A combined prehospital and in-hospital database analysis. Journal of Trauma and Acute Care Surgery ():10.1097/TA.0000000000004540, January 9, 2025.

What Is The Safest Extrication Method From A Car Crash?

Today’s post is directed to all those prehospital trauma professionals out there.

Car crashes account for a huge number of injuries worldwide. About 40% of people involved are trapped in the vehicle. And unfortunately, entrapped individuals are much more likely to die.

There are four basic groups (and their category in parentheses) of trapped car occupants:

  • those who can self-extricate or extricate with minimal assistance (self-extrication)
  • individuals who cannot self-extricate due to pain or their psychological response to the event but can extricate with assistance (assisted extrication)
  • people who are advised or choose not to self-extricate due to concern for exacerbating an injury, primarily spine (medically trapped)
  • those who are physically trapped by the wreckage who require disentanglement (disentanglement and rescue)

Prehospital providers have several choices to help extricate patients in the second and third categories: encourage self-extrication, rapid extrication without tools, or traditional extrication, where the vehicle is cut away to allow egress. The fourth category always requires tools for extrication.

Although rescue services try to minimize or mitigate unnecessary patient movement, stuff happens. Large and forceful movement is considered high risk, but smaller movements do occur. This is of particular concern in patients who might have a spine injury.

There have been several recent papers suggesting there might be greater benefits to self-extrication. A group of authors in the UK and South Africa designed a biomechanical study to test these extrication methods in healthy volunteers.

The authors wanted to determine exactly how much movement occurred using the various extrication techniques. The volunteers were fitted with an Inertial Measurement Unit, which measures the orientation of the head, neck, torso, and sacrum in real-time.  The IMU can detect even minimal changes in the orientation of the body. The volunteers were placed in a standard 5-door hatchback sedans that were prepared for each type of extrication, as seen above.

Here are the factoids:

  • A total of 230 extrications were performed for analysis
  • The smallest amount of maximal and total movement of body segments was seen in the self-extrication group
  • The greatest amount of movement was found in the rapid extrication group, with 4x to 5x the movement in the self-extrication group
  • The difference in body movement between the self-extrication group and all others was significant
  • In general, movement increased as extrication techniques progressed from roof removal to B post removal to rapid extrication

The authors concluded that self-extrication resulted in the smallest amount of movement and the fastest extrication time and should be the preferred technique.

Bottom line: This is the first study that specifically evaluated spinal movement occurring with commonly used extrication techniques. Other similar studies have used various measurement techniques, none of which are as precise as this. One potential weakness with this one is that it used healthy volunteers. But obviously, it is not practical to attempt anything like this with real, injured patients. 

Since we know that patients trapped in cars are more likely to die, time is of the essence. This study shows that self-extrication is both fast and safe with respect to spinal movement. The information will assist our prehospital colleagues in making the best decisions possible when faced with patients trapped in their cars.

Reference: Assessing spinal movement during four extrication methods: a biomechanical study using healthy volunteers. Scand J Trauma  open access 30: article 7, 2022.

Field Amputation Part 6: The Procedure

Preparation and planning will get you just so far. But then, you actually have to act. There are four phases in this procedure. I’ll break them down one by one.

Patient preparation. The area should be shielded from curious onlookers and to control any airborne contaminants (dust, debris) at the scene. Portable monitors should be attached. Good IV/IO access needs to be in place, and the airway controlled via intubation. Adequate anesthesia, analgesia, and sedation must be provided. In addition to pain medication, broad-spectrum antibiotics should be considered, and tetanus toxoid given at some point.

Limb preparation. Expose the extremity, especially the entire area around the amputation site. Wash gross debris off with saline. Place a tourniquet at least 2 inches proximal to the amputation site so it does not interfere with the procedure. Do not tighten until ready to begin. Then prep with betadine or other antiseptic.

The amputation. If that has not been done, administer anesthesia, and tighten the tourniquet. Choose an amputation point as distal as practical to preserve as much future function as possible. Generally speaking, a guillotine amputation is performed; nothing fancy here. Use large blades on the skin, and have plenty of extra blades. It is likely that the blades will get dull quickly in the scene environment. Cut through muscles next, saving the neurovascular bundles until last. These tend to retract when cut, so it is recommended that they be tied first.

Identify the spot where the bone will be cut, and scrape away the periosteum with the scalpel blade. Use an appropriate saw to actually separate the bone. Battery-powered hand-held saws are convenient and reduce the work. However, they may not readily fit into the space available, so a flexible wire (Gigli) saw may be preferred.

Always ensure that someone has been assigned to monitor the patient during the procedure. They need to ensure that everyone is aware of any adverse change in vital signs so that proper adjustments can be made.

Once the amputation is complete, inspect for bleeding, clamping anything that is a problem. It may not be possible to suture and tie given space limitations, so leaving the clamps in place works just fine. Then apply a bulky and compressive dressing, and get out of the way so the EMS providers can do their thing.

The aftermath. Once the patient has been extricated, double check the patient’s ABCs. Make sure the airway is well-placed and secure, or provide one now. Ensure adequate ventilation, and double-check for any bleeding from the amputation site or anywhere else. Then get the patient to definitive care so the trauma team can get to work.

But wait, what about the amputated part? If possible, it should be “dry-packed” in ice (remember the old bag within a bag?) and sent with the patient or soon after. Have you ever wondered why we do that? There is no hope for reimplantation, even if the amputation went flawlessly. There is little real return of function for extremities amputated above the fingers/toes. However, we can use skin and soft tissue from the lost part to help reconstruct the lost limb.

Click this link for a bibliography for this series.

Field Amputation Part 5: The Equipment

We’ve covered all the preparation for field amputation. Now, it’s time to do it! But wait, exactly what equipment is needed? There are two principles that you must adhere to: figure it all out in advance, and keep it simple.

It is crucial that the trauma program design and assemble equipment and drug packs in advance, otherwise critical equipment may not make it to the field. The pack needs to be conveniently located, have fresh instruments and batteries for the equipment, and should have essential anesthetics included. I have included a link to a sample equipment at the end of the newsletter, and I encourage you to download and modify it to suit your needs.

Paralytics, sedatives and analgesics are essential. I prefer vecuronium, midazolam and fentanyl, but there are many other choices. I would discourage the use of propofol because it is difficult to titrate outside the hospital and may contribute to hypotension.

The patient should be intubated prior to starting the procedure. This airway may be difficult due to patient positioning, so be prepared to perform a surgical airway. Ketamine is a good drug in cases where intubation is not possible. Finally, don’t assume that the patient will be conveniently positioned supine. Rescue workers may need to support the patient (or you) if he or she is in an awkward position.

Finally, don’t assume that you will accompany the patient (and possibly their limb) back to the hospital. Based on the specific aircraft used, there may not be room available. You may return by ground transportation or another aircraft. That’s why the backup surgeon needs to be mobilized!

Click this link to a sample equipment list.

The next and final post will review the field amputation procedure.

Field Amputation Part 4: Logistics

Now it’s time to look at the logistics involved in carrying out a field amputation/dismemberment. There are two main considerations here: getting the right people and equipment to the scene and keeping them safe. The following presumes that the procedure will be done by a physician who is based at a trauma center. It will be different if performed by other trauma professionals.

Getting there includes an obvious problem: what happens when the physician leaves the hospital? For emergency physicians, there are generally several on duty, so one will not be missed too much. For surgeons, it’s a bit different. Other surgeons may be available in the hospital during the daytime, although they may have other responsibilities keeping them busy. At night, it becomes much more of an issue, as there may be only one surgeon (or ED physician, for that matter) available for the hospital. They will probably be unavailable for several hours once they are involved in the field amputation process.

The easiest solution is to utilize the backup trauma surgeon. All Level I and II centers must have one available within a “reasonable” time frame, typically 30 minutes. There are two possibilities: the in-house trauma surgeon leaves, the backup proceeds to the hospital for coverage (if in-house is required), or the backup surgeon is transported to the scene, leaving the on-call surgeon to manage as usual.

The choice is up to the trauma center, but this issue needs to be considered in advance. The best solution takes geography into consideration. Since most transports to the scene will be made by helicopter, it is easier to use the trauma center’s helipad to pick up the on-call surgeon. If an in-house surgeon is not used, consideration must be given to the nearest safe landing zone, and this may mean that an out-of-house surgeon would have to travel to the hospital for pick-up.

Once on scene, the physician must ascertain that the area of the incident is safe. This is important for the well-being of the patient, the rescue crews, and the patient. If the scene cannot be made safe, it is impossible to render care, even if the patient is in grave trouble.

Bottom line: Each trauma program and EMS agency must think through these details in advance and develop a policy for who goes to the scene and how they get there. And safety for all is of paramount importance.

The next post will review the equipment needed for field amputation.