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!
The 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.
EMS policy and the trauma center verification process requires that all trauma patients delivered to a trauma center must have a copy of the EMS run sheet. Two parameters that are commonly used to monitor performance improvement (PI) in EMS are:
- accurate record of scene physiology (SBP, HR, RR, GCS)
- request by on-scene BLS for ALS assistance
The study looked at the impact of those criteria on patient survival. A total of 4744 patients from the National Trauma Data Bank were analyzed.
Physiologic data: About 28% had at least one missing physiologic data point, with respiratory rate being most commonly missed. They found that the mortality in the group with missing data was over twice as high (10.3%) as it was in the group with complete date (4.5%).
BLS call for ALS assistance: This assist was called for in 17% of cases. These cases were less likely to involve penetrating injuries and more likely to involve car or motorcycle crashes. Injury Severity Score was the same. Eventual patient mortality was the same for BLS calling ALS and ALS response alone.
So why does failure to record physiologic data translate into higher mortality? The initial response may be that the patient was sicker, and so they needed more intense care during transport with less time to record vitals. However, the researchers controlled for this and found it was not a factor. Other issues that may be a factor are EMS training and proficiency, leadership at the scene and enroute, and available staff and resources, among other things.
The researchers speculate that documentation might be a good global measure of appropriate or inappropriate prehospital care that rolls all of these possible factors into one easily identifiable audit filter. They recommend that this be used to focus performance improvement efforts and hopefully improve survival.
I recommend that the results of this study be taken to heart and used to help persuade EMS programs to get religious about recording complete vital signs and leaving the run sheet at the trauma center every time a patient is delivered. Documentation should be evaluated regularly, and all cases with any missing vital signs should be reviewed closely. Trauma Center PI programs should work with EMS to analyze this data and look for the patterns that increase mortality.
Reference: Lack of Emergency Medical Services documentation is associated with poor patient outcomes: a validation of audit filters for prehospital trauma care. Journal of the American College of Surgeons, 210(2):220-227, 2010.
EMS is very good about immobilizing the spine in trauma patients prior to transporting them to the Emergency Department. Healthcare personnel in the ED are not as good about getting people off of those rigid boards.
As always, it boils down to a risk and benefit assessment. What is the risk of keeping someone on a board, especially if they may have a spine injury? There is a well-known downside to spine immobilization: skin breakdown, which can occur in as little as 2 hours. Less appreciated is the fact that it is very uncomfortable lying on one’s back on any type of board, be it a spine board or even a simple plastic slider board.
What is the risk to the spine if it is indeed injured? In a cooperative patient, essentially zero. Think about it this way: what are spine-injured patients placed on once they are admitted to the hospital? A regular bed with a standard hospital mattress! They are kept on logroll precautions until they have an operative procedure or receive a brace.
The bottom line: All patients should be moved off the EMS spine board onto the ED cart unless they are being transferred to another hospital within an hour or less. The ED cart should have a regular mattress, but the patient must be cooperative. If they cannot or will not cooperate, and the probability of spine injury is high, they may need to be chemically restrained. A plastic slider board may be placed under the patient when they are ready to go to diagnostic studies, and should be removed immediately when they are complete. No board of any kind should ever be left under a patient for more than 2 hours.