Tag Archives: EMS

Prehospital

Prehospital Lactate: Ready For Prime Time?

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A few months ago, I started to notice a new piece of information coming across on my trauma activation pages: point of care lactate level. I had heard nothing about this prior to these pages, and was curious to know whether this was a new policy/practice, or some study that was in progress. So, of course, I had to do a little bit of reading to find out what was up with that. I’ll share that with you today.

Serum lactate has been used since forever in the inpatient setting, especially in the ICU. It is used as a surrogate for tissue hypoxia and/or metabolic acidosis. A number of studies have found that hypoperfusion is frequently underappreciated, since we tend to use crude vital signs (BP and pulse) which may look normal in early hypovolemia. Serum lactate guided therapy has been shown to improve survival in some studies, and can indicate that resuscitation is proceeding appropriately. Patients who do not show early improvement in their lactate levels are more likely to be refractory to resuscitation, and have higher mortality.

So it would make sense that if prehospital trauma professionals could identify occult tissue hypoperfusion in the field, appropriate resuscitation could start earlier. And nowadays, one can find a point of care device to measure just about anything. Thus, the extra tidbit of information on my trauma pages.

But remember, just because something makes sense doesn’t mean that it actually works. Thus, a group at the University of Birmingham (in the UK) did a systematic review of the literature through 2015, looking specifically at lactate levels obtained in the prehospital setting.

Here are the factoids:

  • Of the 2,415 articles screened, only 7 were suitable for analysis
  • These studies were judged to be of “low” or “very low” quality
  • The methods by which the lactate level were obtained (venous vs capillary), timing, and documentation were highly variable
  • The authors concluded that there is not yet enough data to support point of care lactate in the field

Bottom line: Point of care lactate drawn in the field would seem to be a good idea. Unfortunately, there aren’t any studies yet that are good enough to make this a standard practice. As with any new technique, if there’s no data then you MUST participate in a well designed study so it can be shown, yea or nay, that the practice is a good one. So join up!

Reference: Prehospital point-of-care lactate following trauma: a systematic review. J Trauma 81(4):748-755, 2016.

Prehospital

Validation Of The Air Medical Prehospital Triage Score (AMPT)

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Unneeded use of helicopter emergency medical services (HEMS) air transport is a problem around the world. This scarce and valuable resource tends to be over-utilized, resulting in unnecessary costs to patients and the health care system in general. Unfortunately, good and objective criteria for HEMS transport have been hard to come by.

A group at the University of Pittsburgh published a study earlier this year, developing an objective scoring system based on a huge dataset from the National Trauma Databank. They used a portion of the data to develop a model, and the remainder to test it. They developed the AMPT, which identified patients that showed a survival benefit with helicopter transport:

AAST2016-Oral23

For this AAST abstract,  they sought to validate the scoring system using an entirely different database, the Pennsylvania Trauma Systems Foundation registry. They used 14 years of data, and reviewed nearly a quarter million records. Once again, the authors were looking at in-hospital survival.

Here are the factoids:

  • 20% of patients were transported by air
  • But only 11% were predicted to benefit by using AMPT
  • For patients with an AMPT score < 2, transport by air did not increase survival
  • For patients who had an AMPT score >2 and were actually transported by air, survival was improved by 31% (!)

Bottom line: It looks like the AMPT score is a good predictor of improved survival for patients transported by air. But wait, it’s not that cut and dried. These statistics are based on populations; they cannot predict exactly which individual patient will benefit. What about those patients who actually died? Perhaps if they had gotten to the hospital a little faster, they would have done better? This is certainly a nice new tool to use in the decision-making process, but it can’t be the only one. 

References:

  • The air medical prehospital triage score: external validation supports ability to identify injured patients that would benefit from helicopter transport. AAST 2016, Paper #23.
  • Development and validation of the air medical prehospital triage score for helicopter transport of trauma patients. Ann Surg 264(2):378-385, 2016.
General

Prehospital Lift-Assist Calls

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Here’s something I was completely unaware of until just a few years ago. A number of 9-1-1 calls (quite a few, I am told) are made, not for injury or illness, but because the caller needs help getting back into bed, chair, etc. It is also common that prehospital providers are frequently called back to the same location for the same problem, or a more serious one, within hours or days.

Yet another study from Yale looked at the details of lift-assist calls in one city in Connecticut (population 29,000) during a 6 year period. The town has a fire department based EMS system with both basic and advanced life support, and they respond to 4,000 EMS calls per year.

Here are the factoids:

  • Average crew time was about 20 minutes
  • 10% of cases required additional fire department equipment, either for forced entry or for assistance with bariatric patients
  • About 5% of all calls were for lift-assist, involving 535 addresses
  • Two thirds of all calls went to one third of those addresses (174 addresses)
  • There were 563 return calls to the same address within 30 days (usual age ~ 80)
  • Return calls were for another lift-assist (39%), a fall (8%), or an illness (47%)

Bottom line: It looks to me that we are not doing our elderly patients any favors by picking them up and putting them back in their chair/bed. Lift-assist calls are really a sentinel event for someone that is getting sick or who has crossed the threshold from being able to live independently to someone who needs a little more help (assisted living, etc). Prehospital personnel should systematically look at and report the home environment, and communities should automatically involve social services to help ensure the health and well being of the elder. And a second call to the same location should mandate a medical evaluation in an ED before return to the home.

Reference: A descriptive study of the “lift-assist” call. Prehospital Emergency Care 17(1):51-56, 2013.

General

EAST 2016: Pain And Tourniquet Efficacy

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Ischemia hurts. And tourniquets induce ischemia
on purpose. So logically, tourniquet application should hurt. In a hospital
setting, Doppler ultrasound is used to confirm loss of arterial inflow to the
extremity. In the field, the usual end point is cessation of bleeding. The idea
is to stop tightening the moment that bleeding stops. Unfortunately, this is
not very exact. So the next question is, can pain after tourniquet application
be used to predict how well it is working?

The group at Cook County in Chicago measured
pressures, arterial occlusion, and pain in various extremities in a group of
healthy volunteers (!!). Fortunately for them, complete occlusion was only
maintained for a minute.

Here are the factoids:

  • Three tourniquet systems were used: an
    in-hospital pneumatic tourniquet, the CAT™, and the SWAT™
  • Readings were taken on left and right upper
    arms, the forearms, legs, and the right thigh
  • Using a pain scale of 0-10, tourniquet
    application did not generally induce severe pain
  • Pain scores were 1-3 in the upper arms and forearms,
    3-4 in the thigh, and 2-3 in the leg

Bottom
line: Strangely enough, tourniquet application did not produce severe pain in
any of the subjects. Thigh application tended to be more painful. But,
generally speaking, pain cannot be used as an indicator of effective
application. In the field, cessation of bleeding is the best indicator. And in
the hospital, Doppler ultrasound confirmation should be the standard. In any
case, if the patient is experiencing undue pain after application, check the tourniquet and its positioning.
Something else might be wrong!

Reference:
Pain is an accurate predictor of tourniquet efficacy. EAST 2016 Poster abstract
#23.

General

EAST 2016: Scene Time And Mortality

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The old “scoop and run” vs “stay and play” debate has gone on for years. It would seem to be intuitive that trauma patients, who should be assumed to be bleeding to death, would do better with shorter prehospital times and quicker transport to definitive care. 

However, several studies have not shown worse outcomes in the “stay and play” patients. Once again, mortality is a very crude indicator of “worse” outcomes, and may not be a good enough measure. Nonetheless, the debate continues to rage. A group at the University of Pittsburgh used the Pennsylvania Trauma Registry to review a huge number of EMS transports, looking at mortality as the measure of interest.

Recognizing that total prehospital time can be influenced by delays in specific phases (response, scene, or transport), they analyzed the impact of problems in each. If one particular phase represented more that 50% of the total prehospital time, it was considered a delay. Logistical regression was used to match patients to try to control for any confounding issues.

Here are the factoids:

  • Over 164,000 records with prehospital times were reviewed over a 14 year period.
  • There was a statistically significant increase in mortality if the scene time phase was prolonged.
  • No differences in mortality were noted with longer response or transport times.
  • Prolonged extrication and intubation had a tendency to prolong scene time, and were independently associated with higher mortality.
  • Lengthy scene time without extrication or intubation was not associated with higher mortality.

Bottom line: This registry-based study has helped us to slice and dice the prehospital time issue a little bit better. As with other studies, the times themselves may not necessarily be the problem. It’s what is causing the delay that matters. Extrication and intubation tend to indicate sicker trauma patients, but they are also somewhat unavoidable. Prehospital trauma professionals will need to focus on tools and exercises that save time during these critical interventions.

Reference: Not all prehospital time is equal: influence of scene time on mortality. EAST 2016 Oral abstract #9, resident research competition.