Tag Archives: prehospital

Can Prehospital Providers Accurately Estimate Blood Loss?

EMS providers are the trauma professional’s eyes and ears when providing transportation from the scene of an accident. We rely on their assessment of the mechanism of injury and the amount of blood lost. We tend to believe in the accuracy of those assessments.

A study was carried out that tested EMS personnel on their ability to accurately estimate specific amounts of blood that were left at a simulated accident scene. The blood volumes tested were 500cc, 1000cc, 1500cc and 2100cc. A total of 92 professionals participated, and there was an even split into basic EMTs (34%), intermediate/critical care EMTs (33%) and paramedics (31%). Experience levels were as follows: 0-5 years 43%, 6-10 years 30%, >10 years 31%.

The results were as follows:

  • 87% underestimated the quantity of blood
  • 9% overestimated
  • 4% guessed the exact amount
  • Experience or credentialing level did not matter

Only 8% of the subjects were within 20% of the actual volume, and an additional 19% were within 50%. In general, most medics underestimated the amount of blood lost, and their guesses were worse with higher volumes. The median guess for the 2100cc loss group was only 700cc!

EMS Blood Loss Estimates

Bottom line: Visual estimates of blood loss are extremely inaccurate, and are most likely  underestimates. Physicians in the ED should rely on exam and physiology to help determine the amount of blood loss. For safe measure, multiply the reported blood loss of the EMT or paramedic by 2 or 3 to get a realistic number.

Reference: Patton et al. Accuracy of Estimation of External Blood Loss by EMS Personnel. J Trauma 50(5), 914, 2001.

Validation Of The Air Medical Prehospital Triage Score (AMPT)

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:


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 >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. 


  • 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.

The EMS Second IV In Trauma

One of the critical maneuvers that EMS providers perform is establishing initial vascular access. This IV is important for administering medications and for initiating volume resuscitation in trauma patients. Prehospital Trauma Life Support guidelines state that every trauma patient should receive two large bore IV lines. But is this really necessary?

The upside of having two IVs in the field is that the EMS provider can give lots of volume. However, a growing body of literature tells us that pushing systolic blood pressure up to “normal” levels in people (or animals) with an uncontrolled source of bleeding can increase mortality and hasten coagulopathy.

The downside of placing two lines is that it is challenging in a moving rig, sterility is difficult to maintain, and the chance of a needlestick exposure is doubled. So is it worth it?

A group at UMDNJ New Brunswick did a retrospective review of 320 trauma patients they received over a one year period who had IV lines established in the field. They found that, as expected, patients with two IVs received more fluid (average 348ml) before arriving at the hospital. There was no increase in systolic blood pressure, but there was a significant increase in diastolic pressure with two lines. The reason for this odd finding is not clear. There was no difference in the ultimate ISS calculated, or in mortality or readmission.

Bottom line: This study is limited by its design. However, it implies that the second field IV is not very useful. The amount of extra fluid infused was relatively small, not nearly enough to trigger additional bleeding or coagulopathy. So if another IV does not deliver significant additional fluid and could be harmful even if it did, it’s probably not useful. Prehospital standards organizations should critically look at this old dogma to see if it should be modified.


  • Study of placing a second intravenous line in trauma. Prehospital Emerg Care 15:208-213, 2011.

Prehospital Lift-Assist Calls

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. 

Some interesting results:

  • 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, online ahead of print, September 2012.

Bystander CPR For People Not In Cardiac Arrest

CPR has increased the survival rate of patients suffering cardiac arrest, and early bystander CPR has been shown to double or triple survival. The sad truth is that CPR is not frequently performed by the general public. The American Heart Association has attempted to simplify CPR to the point that even untrained bystanders can administer chest compressions without a pulse check and without rescue breathing.

Bystander CPR

But what happens if that well-intentioned bystander starts CPR in someone who has not arrested? How often does this happen? Can the patient be injured?

The Medical College of Wisconsin reviewed the charts of all patients who received bystander CPR in Milwaukee County over a six year period. There were 672 incidents of bystander CPR. Of those cases, 77 (12%) were not in arrest when assessed by EMS personnel, and the researchers focused on those patients.

EMS response time averaged 5 minutes, and was greater than 10 minutes in only 2 cases. Average patient age was 43(!). The male/female ratio was just about 50:50, and the majority of the incidents took place in the home or residence.

Hospital records were available for further analysis in 72 of the patients. A quarter were sent home, a quarter admitted to a ward bed, and half were admitted to an ICU. Only 12 (17%) had a cardiac-related discharge diagnosis. The next most common discharge diagnoses were near-drowning, respiratory failure and drug overdose. Younger patients (<19) were usually near-drowning victims, and older patients (>54) were most commonly diagnosed with syncope. Five patients did not survive. Only one CPR injury was identified, which was charted as rhabdomyolysis “secondary to having received CPR” (a weak injury diagnosis, in my opinion).

Bottom line: The potential benefit of bystander CPR outweighs the risk of injury or performing it on a victim who is not in arrest. This study shows that, although these patients may not need CPR, they are generally very ill. Given the rapid EMS response times and the younger average age of the victims, no real injuries occurred. The new American Heart Association recommendations are beneficial and should be distributed widely.

Reference: The frequency and consequences of cardiopulmonary resuscitation performed by bystanders on patients who are not in cardiac arrest. Prehosp Emerg Care 15:282-287, 2011.