Tag Archives: EMS

Prehospital

What Is The Safest Extrication Method From A Car Crash?

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

Car crashes account for a huge number of injuries world-wide. About 40% of people involved in them are initially 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 the use of 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 movement of the patient, stuff happens. Large and forceful movement is considered high risk, but smaller movement do occur. This is of particular concern in patients who might have a spine injury.

There have been a number of 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 methods of extrication in healthy volunteers.

The authors wanted to find out 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 very small changes in 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 that it 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 a variety of 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 car.

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

Prehospital

Uber / Lyft For Medical Transport???

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In this day and age of ride sharing apps like Uber and Lyft, it is possible to get a cheap ride virtually anywhere there is car service and a smart phone. And of course, some people have used these services for transportation to the hospital in lieu of an ambulance ride. What might the impact be of ride services on patient transport, for both patient and EMS?

Ambulance rides are expensive. Depending on region, they may range from $500-$5000. And although insurance may reduce the out of pocket cost, it can still be expensive. So what are the pros vs the cons of using Uber or Lyft for medical transport?

Pros:

  • Ride shares are inexpensive compared to an ambulance ride
  • They may arrive more quickly because they tend to circulate around an area, as opposed to using a fixed base
  • Riders may select their preferred hospital without being overridden by EMS (although it may be an incorrect choice)
  • May reduce EMS usage for low acuity patients

Cons:

  • No professional medical care available during the ride
  • May end up being slower due to lack of lights and siren
  • Damage fees of $250+ for messing up the car

A very interesting paper suggests that ambulance service calls decreased by 7% after the introduction of UberX rides.  The authors mapped out areas where UberX rides were launching, and examined emergency response data in these areas. They used a complex algorithm to examine trends over time in over 700 cities in the US, and used several techniques to try to account for other factors. Here is a chart of the very fascinating results:

Bottom line: Uber and Lyft are just another version of the “arrival by private vehicle” paradigm. Use of these services relies on the customer/patient having very good judgment and insight into their medical conditions and care needs. And from personal experience, this is not always the case. I would not encourage the general public to use these services for medical transport, and neither do the companies themselves!

Reference: Did UberX Reduce Ambulance Volume? Health Econ 28(7)L817-829, 2019.

Prehospital

Trauma Activation vs Stroke Code

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Let’s look at an uncommon scenario that crops up from time to time. Most seasoned trauma professionals have seen this one a time or two:

An elderly male is driving on a sunny afternoon, and crashes his car into a highway divider at  25 miles per hour. EMS responds and notes that he has a few facial lacerations, is awake but confused. They note some possible facial asymmetry  and perhaps a bit of upper extremity weakness. No medical history is available. Witnesses state that he was driving erratically before he crashed. Medics call the receiving trauma center in advance to advise them that they have a stroke code.

Is this a reasonable request? Stroke centers pride themselves on the speed of their stroke teams in assessing, scanning, and when appropriate, administering thrombolytics to resolve the problem. But if there are suspicions of stroke in a trauma patient, which diagnosis wins? Trauma team or stroke team?

Lets analyze this a bit further, starting with diagnosis. Remember the first law of trauma:

Any anomaly in your trauma patient is due to trauma, no matter how unlikely it may seem.

Could the symptoms that the paramedics are observing be due to the car crash? Absolutely! The patient could have a subdural or epidural hematoma that is compressing a cranial nerve. There might be a central cord injury causing the arm weakness. His TBI might be the source of his confusion. The facial asymmetry could be due to a pre-existing Bell’s palsy, or he could have had a stroke years ago from which he has only partially recovered.

If the stroke team is called for the patient, they will focus on the neuro exam and the brain. They will not think about trauma. They will follow the patient to CT scan looking for the thing that they do best with. If they don’t see it, the patient will return to the ED for (hopefully) a full trauma workup. If there are occult injuries in the abdomen, then the patient may have been bleeding for an hour by then. This elderly patient will then be way behind the eight ball.

And let me pose the worst case scenario. The patient is taken to CT by the stroke team, and lo and behold he has a thrombotic stroke!  This patient had a stroke, which caused him to lose control of his car and explains most of his findings. Again, the stroke team will do what they are trained to do and give a thrombolytic. They are still not thinking about trauma. Within minutes the patient becomes hypotensive and his abdomen appears a bit more distended. He is rushed back to the ED (remember, no CT in hypotensive patients even if you are in the scanner) and a FAST exam is very positive for free fluid throughout the abdomen. Imagine the look you will get from the surgeon as they run to the OR to perform a splenectomy on this fully anticoagulated patient!

Bottom line: If you have a patient who is trauma vs stroke, trauma always wins! Remember the first law and try to find traumatic reasons for all signs and symptoms. Perform your standard trauma workup and incorporate the appropriate head scans into your evaluation. Then and only then should the stroke team be called.

Prehospital

How Long Does It Take EMS To Get To A Scene?

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How long does it take for EMS to get to the scene of an emergency? That’s a loaded question, because there are many, many factors that can impact this timing. If you look at the existing literature, there are few, if any, articles that have actually looked at this successfully.

A group from Aurora, IL and Wake Forest reviewed EMS records from across the country, spanning 485 agencies over a one year period. Only 911 responses were reviewed, and outliers with arrival times of more than 2 hours and transport times of 3 hours were excluded. Over 1.7 million records were analyzed, and 625 were excluded for this reason.

Here are the factoids:

  • In 71% of cases, the patient was transported to a hospital. In one quarter of cases, they were evaluated but not transported. 1% were dead on arrival, and in 2% no patient was found at the scene (!)
  • 4% of patients were transported in rural zip codes, 88% in suburban ones, and 8% from urban locations
  • Overall response time averaged 7 minutes
  • Median response times were 13 minutes for rural locations, and 6 minutes for both suburban and urban locations
  • Nearly 1 in 10 patients waited 30 minutes for EMS response in rural locations

Bottom line: There is an obvious difference in EMS response times between rural and urban/suburban locations. And there are many potential reasons for this, including a larger geographic area to be covered, volunteer vs paid squads, etc. Many of these factors are difficult, if not impossible to change. The simple fact that it takes longer to reach these patients increases their potential morbidity and mortality. Remember, time is of the essence in trauma. The patient is bleeding to death until proven otherwise. It is far easier and cost-effective to equip bystanders with the skills to assist those in need (basic first aid, CPR, Stop the Bleed, etc) while waiting for EMS to arrive.

Reference: Emergency Medical Services Response Times in Rural, Suburban, and Urban Areas.  JAMA Surg 152(10): 983–984, 2017.

Prehospital

Can Prehospital Providers Accurately Estimate Blood Loss? Part 2

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I’ve previously written about the difficulties estimating how much blood is on the ground at the trauma scene. In general, EMS providers underestimated blood loss 87% of the time. The experience level of the medic was of no help, and the accuracy actually got worse with larger amounts of blood lost!

A group in Hong Kong developed a color coded chart (nomogram) to assist with estimation of blood loss at the scene. It translated the area of blood on a non-absorbent surface to the volume lost. A convenience study was designed to judge the accuracy that  could be achieved using the nomogram. Sixty one providers were selected, and estimated the size of four pools of blood, both before and after a 2 minute training session on the nomogram.

Here’s what it looks like:

Note the areas across the bottom. In addition to colored square areas, the orange block is a quick estimate of the size of a piece of paper (A4 size since they’re in Hong Kong!)

Here are the factoids:

  • The 61 subjects had an average of 3 years of experience
  • Four scenarios were presented to each: 180ml, 470ml, 940ml, and 1550ml. These did not correspond exactly to any of the color blocks.
  • Before nomogram use, underestimation of blood loss increased as the pool of blood was larger, similar to the previous study
  • There was a significant increase in accuracy for all 4 scenarios using the nomogram, and underestimation was significantly better for all but the 940ml group
  • Median percentage of error was 43% before nomogram training, vs only 23% after. This was highly significant.

Bottom line: This is a really cool idea, and can make estimation of field blood loss more accurate. All the medic needs to do is know the length of their shoe and the width of their hand in cm. They can then estimate the length and width of the pool of blood and refer to the chart . Extrapolation between colors is very simple, just look at the line. The only drawback I can see occurs when the blood is on an irregular or more absorbent surface (grass, inside of a car). 

Related posts:

Reference:  Improvement of blood loss volume estimation by paramedics using a pictorial nomogram: a developmental study. Injury article in press Oct 2017.