1. Comparison of law enforcement officer – versus emergency medical services – placed tourniquets. Shukla D, Shapiro G, Smith ER, Sarani B. J Trauma Acute Care Surg. 2024;97:552–556.
2. Cost Savings of Whole Blood Versus Component Therapy at a Community Level 1 Trauma Center. Murphy RC, Johnson TW, Mack TJ, et al. Amer Surg 2024;90:2156-2159.
3. Traditional Spinal Immobilization versus Spinal Motion Restriction in Cervical Spine Movement; a Randomized Crossover Trial. Nuanprom P, Yuksen C, Tienpratarn W, Jamkrajang P. Arch Acad Emerg Med. 2024;12(1):e36. Full text available on-line at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11088786/
4. The Association of Prehospital End-Tidal Carbon Dioxide with Survival Following Out-of-Hospital Cardiac Arrest. Smida T, Menegazzi JJ, Crowe RP, Salcido DD, Bardes J, Myers B. Prehosp Emerg Care 2024;28:478-484.
International Prehospital Medicine Institute Literature Review, October 2024
1. Comparison of law enforcement officer – versus emergency medical services – placed tourniquets. Shukla D, Shapiro G, Smith ER, Sarani B. J Trauma Acute Care Surg. 2024;97:552–556.
Tourniquet placement for extremity hemorrhage is now an accepted treatment by prehospital and public safety personnel and is routine part of prehospital protocols. Patients with life-threatening extremity bleeding have improved mortality if a prehospital tourniquet is placed prior to the onset of shock. However, overuse of tourniquets is recognized as a problem since tourniquet placement usually results in transport to a trauma center and full activation of the trauma team. This results in overtriage, increasing the burden on already busy trauma centers. Increasingly, law enforcement officers (LEOs) are placing tourniquets. However, a study from 2015 showed only 49% of LEOs had received tourniquet-specific training. Additionally, many EMS agencies do not allow for removal of a tourniquet once it is placed.
This study assessed the differences in proper indications for tourniquet placement between LEOs and EMS. The authors hypothesized that LEOs are more liberal with the placement of tourniquets than EMS. This was a retrospective, single-center study of adult trauma patients who received a prehospital tourniquet between 2016 and 2023. The data were stratified based on the type of provider who placed the tourniquet (LEO vs EMS).
A total of 192 patients were included in the study. Of these 192 patients, 77 (40%) were placed by a LEO and 120 (62.5%) were placed by EMS. Five patients had more than one tourniquet placed. All patients arrived by ambulance. The median time from arrival of EMS on-scene to the trauma bay was 20 minutes. The authors were not able to determine the time of tourniquet placement by either LEO or EMS. All tourniquets were commercially available tourniquets. All patient variables (age, sex, injury severity, etc) were similar between the groups. The majority of tourniquets placed by both groups were on the thigh (LEO 43%, EMS 36%). The majority of tourniquets placed by both groups were removed in the trauma bay, indication the bleeding wasn’t actually severe. However, LEO-placed tourniquets were significantly more likely to be removed in the trauma bay (83% vs 73%). Of the 64 tourniquets placed by LEO and removed in the trauma bay, only 12.5% had recurrent bleeding, while in the EMS group 18.4% had recurrent bleeding. Tourniquets placed by EMS were more likely to require operative control of hemorrhage, although the total was low in both groups (EMS 23% vs LEO 6%). There were no complications noted at discharge from tourniquets placed by either group.
This study has several limitations. It is a single-center study so results may not correlate with other trauma systems. It is subject to the dataset limitations of a retrospective study and because it was retrospective the authors were unable to determine if a tourniquet was placed correctly. The authors were unable to determine the time of tourniquet placement as it was inconsistently recorded.
This study confirms previous studies that most prehospital tourniquets are not necessary and are removed in the trauma bay. This was more common with tourniquets placed by LEO. Many EMS systems do not allow for removal of a tourniquet once it is placed. The authors note that changes in prehospital protocols to allow for EMS providers to remove tourniquets placed by LEO to reassess for major hemorrhage could result in less overtriage to trauma centers and over-activation of trauma teams. Additionally this study supports increased training of LEOs in hemorrhage recognition and hemorrhage control techniques.
2. Cost Savings of Whole Blood Versus Component Therapy at a Community Level 1 Trauma Center. Murphy RC, Johnson TW, Mack TJ, et al. Amer Surg 2024;90:2156-2159.
More and more EMS agencies are exploring the use of prehospital blood products. Currently there are two major resuscitation protocols, blood component only resuscitation (CORe) and Whole Blood (WB). CORe resuscitation involves a 1:1:1 transfusion process of packed red blood cells, fresh frozen plasma, and platelets in an attempt to replicate whole blood. EMS medical directors and leaders need to consider many things when deciding which protocol to follow. The first is survival advantage for the patient. Additionally, the type and availability of blood products in the service area needs to be considered. As stewards of the blood supply, blood banks and providers need to do what they can to reduce waste. Lastly, the cost of blood products also needs to be considered.
The authors of this single center, institutional review board approved, retrospective study of adult trauma patients, treated at a community trauma center, attempted to compare the total hospitalization costs of WB versus CORe. Additionally, they looked at their number of massive transfusion protocol (MTP) activations, blood product waste, patient mortality and the length of ICU stays including ventilator days. It should be noted that blood component and whole blood storage and administrative fees, including type and cross match, were included in the cost of analysis. Waste was determined by the blood bank and defined as any unused blood product that was deployed and not returned to the blood bank in time for redeployment.
Trauma patient charts treated between 1 January 2017 and 31 December 2021 were included for review. Prior to 2019, CORe protocols were the institution’s sole blood resuscitation option. In 2019 WB resuscitation (low titer O+) was included in the resuscitation protocol. Five hundred and seventy-six patients were included in the study (201 in the WB group and 375 in the CORe group). Injury severity scores were closely matched between the two groups (24.4 vs 25.6).
The authors found a survival advantage in the WB group (OR 1.49, P=.0371). There was no difference in the length ICU stays or ventilator days. There was 44% increase in patient volume between 2018 and 2022 and a 21% reduction in mortality. The authors reported a $3.39 million cost savings over four years ($846,923 annual) following the use of WB. There was a 38.7% reduction of blood product waste following adoption of WB resuscitation. WB also resulted in a 56.3% reduction in MTP activations.
Limitations of this study include its single center, retrospective design. The sample size was also small. This was a hospital only study and results, especially regarding waste, may not transfer to the prehospital environment.
This relatively small study demonstrated whole blood resuscitation resulted in greater patient survival over blood component resuscitation while reducing the cost of care. This study should be repeated in an EMS setting to see if the results can be duplicated.
3. Traditional Spinal Immobilization versus Spinal Motion Restriction in Cervical Spine Movement; a Randomized Crossover Trial. Nuanprom P, Yuksen C, Tienpratarn W, Jamkrajang P. Arch Acad Emerg Med. 2024;12(1):e36. Full text available on-line at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11088786/
Although spinal immobilization practices have been evolving over time, optimal spinal immobilization techniques for out-of-hospital patients with suspected Traumatic Spinal Cord Injury (TSCI) remains the subject of ongoing debate. The authors of this study sought to compare the Range of Motion (ROM) and the immobilization time between Traditional Spinal Immobilization (TSI) and Spinal Motion Restrictions (SMR).
Healthy, adult volunteers were randomly assigned to one of two groups. Group AB underwent TSI as the initial method followed by SMR. Group BA experienced SMR first and then TSI. TSI involved logrolling a supine patient 90o onto their side, positioning a backboard next to them and then logrolling onto the board, followed by immobilizing them on the board. SMR involved the use of a scoop stretcher, logrolling the patient approximately 15-20o, placing one half of the split scoop stretcher under the patient, and then repeating the procedure on the other side. Straps are then placed to minimize any cervical or head movement. Inertial measurement devices were placed on the subjects’ forehead and chest to measure motion during the procedures.
SMR led to statistically significantly lower ROM in measuring flexion-extension and lateral bending compared to TSI (11o vs 14o) but there was no significant difference in rotational movement between the two procedures. They did note that it took slightly longer to perform SMR than TSI (11.8 seconds) which was statistically significant but not felt to be clinically significant.
The authors cited the small sample size, the use of healthy volunteers over actual trauma patients, and the fact there were additional measurements they did not make, i.e. patient comfort, as limitations of their study. Also the lack of blinding of the participants and researchers could introduce observer bias. Lastly, no information for the specific angle of cervical spine movement resulting in unfavorable neurological outcomes was available.
The authors concluded that SMR utilizing scoop stretchers “demonstrated greater efficacy in limiting patient cervical spine movement compared to TSI using a LSB.” While the amount of movement was statistically significant it is unknown if this 3o difference would be clinically significant. They stated that the increased amount of time needed for SMR over TSI was not significant. They noted that further investigation on actual trauma patients and evaluating long-term effects of SMR using a scoop stretcher is recommended.
4. The Association of Prehospital End-Tidal Carbon Dioxide with Survival Following Out-of-Hospital Cardiac Arrest. Smida T, Menegazzi JJ, Crowe RP, Salcido DD, Bardes J, Myers B. Prehosp Emerg Care 2024;28:478-484.
End-tidal carbon dioxide (ETCO2) measurements have long been used in the prehospital environment, first to assess advanced airway placement and then as a clinical tool to assess the patient’s perfusion and respiratory status. Past studies have suggested that patients with a low ETCO2 level (less than 10 mmHg) after 20 minutes of resuscitation had a 100 percent sensitivity for mortality. Many EMS services include the use of ETCO2 as a part of the decision tree used to terminate resuscitation.
The authors of this retrospective review examined patients in cardiac arrest prior to EMS arrival. The goal of the study was to determine the association between prehospital ETCO2 production pre- and post-ROSC and survival to hospital discharge. Data was obtained from 2018-2021 utilizing the ESO Data Collaborative.
A total of 286,192 patients with out-of-hospital cardiac arrest (OOHCA) were identified. After exclusion criteria, 117,991 patients were enrolled in the study.
The authors noted that, “Low and high prehospital ETCO2 values were associated with increased mortality in this large dataset.” The authors of this study found that low ETCO2 had high specificity but low sensitivity for survival, possibly due to improved resuscitation techniques like continuous chest compressions (“pit crew CPR”) and other enhancing changes in cardiac arrest care. However, a secondary analysis did not fully replicate earlier studies, which suggested that ETCO2 values below 10 mmHg at 20 minutes post-ALS initiation were highly predictive of mortality and survival. The study confirmed the findings of a 1997 study that observed a similar U-shaped association of ETCO2 with survival using the French National Cardiac Arrest Registry. The authors go on to state “Contemporary resuscitation practices may make low ETCO2 values uncommon, and field termination decision algorithms should not use ETCO2 values in isolation.”
The authors note that this study’s main limitations include missing covariables of interest, such as the time of initiation of ALS and the administration of certain drugs that could affect the ETCO2. Furthermore, the actual capnography waveforms were not available for review to assess for equipment issues and sampling errors. This study also used some patients and data obtained during the COVID-19 epidemic, which could skew the data.
The widespread use of waveform capnography is one of the great advancements in prehospital resuscitation efforts in the last two decades. While this study replicates earlier studies showing that both low and high ETCO2 values are associated with higher mortality, it is important to consider that the population, the underlying causes of cardiac arrest such as the opioid epidemic, and the management of OOHCA have changed over time. ETCO2 values alone should not be used when making field termination decisions.
