Good afternoon. My name is Dr. Jonathan Trager, and I am an attending physician in the Departments of Emergency Medicine and Critical Care Medicine at St. Luke's University Hospital in Bethlehem, Pennsylvania. I am also the Medical Director of our hospital's Emergency and Transport Program, as well as our Critical Care Transport Division, and a practicing pre-hospital physician in Pennsylvania. I'm going to speak to you today on the topic of pre-hospital care and initial stabilization and transfer of the critically ill patient. I have no disclosures at this time. The objectives of this talk are to review literature related to pre-hospital critical care interventions, and the focus of this topic will be on stop the bleeding or hemorrhage control options. The article that I have chosen to review is pre-hospital whole blood reduces early mortality in patients with hemorrhagic shock by Dr. Maxwell Braverman and his colleagues. Whole blood transfusion has been experiencing a resurgence of interest, mostly after our recent conflicts in Iraq and Afghanistan, where resuscitation with whole blood was implemented in practice in essentially all phases of care for the injured soldiers, and has also been incorporated into the guidelines for tactical combat casualty care as a first-line agent of hemorrhagic shock resuscitation. It's also preferred because of its ease of administration compared to standard therapy, which has been component therapy, or as most of us are familiar with, the one-to-one-to-one ratio of packed with blood cells to fresh frozen plasma and platelets. Furthermore, our pre-hospital colleagues do have limited therapeutic capabilities when treating trauma patients, especially those with significant hemorrhage and or penetrating injuries, and this therapy will provide them with an additional option that may actually have benefits in saving their patients who are injured. The study objectives, as outlined in the paper, are to determine if pre-hospital low titer O-hole blood, LTOWB transfusions, compared to no pre-hospital LTOWB transfusions, improve survival in three distinct groups of trauma patients, those receiving in-hospital transfusions only, those sustaining pre-hospital cardiac arrest, and those patients with development of shock physiology in the field. Not yet ready for prime time in the United States necessarily, but perhaps opportunities for the future, especially in situations of mass casualty incidents or mass gathering events, would be implementation of what the 75th Ranger Regiment was able to accomplish using a walking blood bank known as their ROLO program or Ranger Olo Titer program for battlefield blood transfusions by identifying the most ideal candidates for donation and pulling blood from them on the battlefield for rapid transfusion. To conduct this study, the Institutional Trauma Registry at a specified academic level and trauma center was queried from the years 2015 to 2019 for consecutive adult patients who underwent blood transfusions after their arrival to the emergency department. Incomplete records were defined as those that had no documented pre-hospital vital signs or incomplete pre-hospital vital signs that were required for the comparative analysis or those for whom a pre-hospital paper record was unavailable, thus rendering assessment and evaluation of the blood pressure and other vital signs impossible. Patients were then stratified based on receiving pre-hospital low titer O-hole blood identified as PHT or no pre-hospital low titer O-hole blood identified as the NT group. Patients in the NT group either received crystalloid infusion or no infusions while en route to the trauma center. A variety of data was compared to include patient demographics, injury characteristics, pre-hospital vital signs, and arrival vital signs, as well as the mortality in the emergency department at 6 hours, 12 hours, and overall length of stay. Comparisons were also made between the incidence of either massive transfusions defined as greater than 10 units of product transfused in 24 hours or the incidence of transfusion of greater than three units of product in one hour, otherwise identified as Cat 3+. The team also compared the transfusion volumes in the emergency department versus over the total length of stay. Pre-hospital vital signs were defined by the nadir heart rate and systolic blood pressures throughout transport and the corresponding shock index, with shock being defined as a systolic blood pressure less than or equal to 90 millimeters of mercury. The initiation of pre-hospital low titer O-hole blood transfusion was based on specific previously published criteria. The previously published criteria can be found in an alternative paper, the use of pre-hospital blood products in the resuscitation of trauma patients, a review of pre-hospital transfusion practices, and a description of our regional whole blood program in San Antonio, Texas, published in 2019. The left side of the screen depicts the setup and organization of the regional whole blood program, and the right side of the screen, table 2, lists the transfusion criteria in San Antonio for pre-hospital use of low titer O-hole blood. Paramedic guidelines show that whole blood can be administered for patients with systolic blood pressures less than 70 millimeters of mercury, or systolic blood pressure less than 90 with a heart rate greater than 110 beats per minute, or an untitled CO2 less than 25, or witnessed cardiac arrest less than five minutes prior to provider arrival, and continuous CPR throughout, downtime or age greater than or equal to 65 years, and a systolic blood pressure less than 100, and a heart rate greater than 100 beats per minute. They do list relative contraindications to include patients less than six years old, the need to consult medical direction if a patient is in hemorrhagic shock and less than six years old, the medical director may elect to give blood in patients less than six, and of course for religious objections to receiving whole blood. During the study period, a total of 803 patients who underwent transfusion after hospital arrival were identified, with 538 patients remaining for analysis after exclusion of 265 patients due to missing pre-hospital data. Of the 538 patients undergoing transfusion upon arrival, 107 patients received pre-hospital transfusion, with 431 patients in the non-transfusion group. The group was further subdivided into those who sustained pre-hospital cardiac arrest, totaling 40, and a propensity mesh group for patients with pre-hospital shock, totaling 214 patients, of whom 58 received pre-hospital blood transfusion. Table 1 shows the demographics and injury characteristics for all patients undergoing transfusion upon arrival to the trauma bay, and reveals that the pre-hospital transfusion group had a higher incidence of male patients, more penetrating trauma, and a lower median ISS or injury severity score. Table 2 depicts the pre-hospital arrival vital signs, mortality, massive transfusion rates, transfusion volumes upon arrival to the emergency department, and length of stay transfusion volumes for all patients on arrival to the trauma bay. Pre-hospital transfusion patients had a lower pre-hospital nadir systolic blood pressure, higher median heart rate, and a higher nadir shock index compared to the non-transfusion patients. The change in shock index, depicted as delta SI, from nadir to arrival was reduced more significantly in the pre-hospital transfusion group compared to the non-transfusion group. Mortality between the two groups at all time points was not statistically different, however. Although the number of patients in the PHT and NT groups were similar with regard to incidence of massive transfusion, the pre-hospital transfusion group had fewer patients undergoing massive transfusion, defined as greater than 10 units in 24 hours, compared to the non-transfusion group. Overall, pre-hospital transfusion patients required less blood product volume in the emergency department, but ultimately received the same total volume of transfusion over the course of their hospital stay compared to non-transfusion patients. The pre-hospital transfusion group did receive significantly less pre-hospital crystalloid compared to the non-transfusion group, certainly a benefit of providing whole blood. A propensity-matched cohort for patients with pre-hospital shock included a total of 214 patients, 58 of whom received pre-hospital transfusion and 156 who did not. The cohorts were overall similar in demographics and injury characteristics, with a similar median injury severity score, similar median age for both groups. The pre-hospital transfusion patients had a higher percentage of male gender and a higher incidence of penetrating trauma, however. The pre-hospital transfusion and non-transfusion patients had similar median major systolic blood pressures, but the PHT group had a higher median heart rate with a trend towards a higher median shock index prior to transfusion. On arrival to the trauma bay, the patients undergoing pre-hospital transfusion had a lower median heart rate, a trend towards a higher median systolic blood pressure, and a greater improvement in median shock index compared to the non-transfusion patients. Overall, ED mortality was reduced in the pre-hospital transfusion group with a trend towards lower 6-hour mortality. 24-hour mortality and length-of-stay mortality were similar between both groups. There was no difference in incidence of massive transfusion or cat 3 plus transfusion between the groups. Pre-hospital transfusion patients had an overall lower median volume of blood products transfused in the ED on arrival, but ultimately required a larger transfusion volume over their entire hospital stay compared to the non-transfusion patients. One benefit, however, was that the pre-hospital transfusion group also received a significantly lower volume of crystalloid compared to the non-transfusion group. Despite the limitations of the study, the recent addition of whole blood and trauma resuscitation algorithms has led to the potential for improved survival in civilians. For some of the more severely injured patients, earlier reversal of shock physiology has a potential benefit to improve both short- and long-term outcomes. This study illustrates a potential impact of pre-hospital transfusion with low-titer oval blood in the more severely injured patients with hemorrhagic shock. When examining all of the patients transfused upon arrival, despite their higher degree of shock as defined by lower nadir systolic blood pressure and a higher shock index, those that received pre-hospital transfusion exhibited a greater improvement in shock index upon arrival with a resultant reduction in subsequent massive transfusion. In those patients with the most severe shock physiology in the pre-hospital environment, the pre-hospital transfusion cohort demonstrated an overall reduction in trauma-based mortality and a substantial improvement in shock after a low-titer oval blood transfusion compared to those who do not receive blood transfusion. Two downsides, however, was that there was no observed benefit in long-term mortality outcomes between the groups, and there overall did not appear to be a difference in the incidence of massive transfusion based on whether the patient received transfusion or did not. One major benefit of pre-hospital transfusion with blood products, and in this case low-titer oval blood, was the overall reduction of the volume of pre-hospital crystalloids administered to the patients. As has been determined, crystalloid administration should really only be used for patients in shock who require additional volume to improve perfusing pressures and not those who are in hemorrhagic shock. The overall limitations of this particular study are that it is retrospective in nature and overall had a small sample size. Analysis of the original data revealed a significant difference between injury severity and the transfused population across the entire service area. The transfusion decision is also a multifactorial one and allows for significant provider discretion and clinical judgment despite having guidelines to follow. And transfusions were also administered to a variety of patients, not those who were deemed to be in shock. Additional limitations of the study include the lack of available transfusion triggers to the pre-hospital providers at the start of the study period prior to the initiation of the pre-hospital low-titer oval blood program. As a result, a propensity-matched cohort was necessary to allow for appropriate comparisons. This group, while reflective of severely injured patients, does not reflect the entire cohort of transfused patients who undergo pre-hospital transfusion across the service area. Additionally, a large portion of the original study cohort was excluded based on missing pre-hospital records. Nationally, seen vital signs are defined as vital signs obtained prior to leaving the scene of injury. As would be expected, a large number of patients are initially hemodynamically normal and progress towards shock while en route to the hospital, leading to the use of the nadir systolic blood pressure in this study as it more closely reflects the patient's vital signs at the time of transfusion. Unfortunately, some of these records were not universally available or in some cases were incomplete, and thus did not allow for accurate comparisons of these groups, leading to a significant number of exclusions. Despite the limiting factors in this study, the administration of low-titer oval blood by our pre-hospital providers showed a greater improvement in shock index and a reduction in early mortality in those patients arriving at the trauma bay. Currently, our providers have a limited arsenal of therapies which they can use to help those patients suffering from traumatic injury and specifically hemorrhagic shock, and this tool certainly looks like it would be beneficial. Moving forward, however, additional studies will need to be completed, preferably those from a prospective nature involving multiple institutions and multiple EMS jurisdictions. I have listed here additional studies on this topic of pre-hospital blood transfusion that are worthy of your review. I would like to thank you for your undivided attention. I am happy to answer any questions. Please feel free to email me, and I would like to give a shout out to my exemplary EMS and critical care transport crew at St. Luke's Emergency and Transport Services. Thank you very much. Have a great day.

pre-hospital care

hemorrhage control

whole blood transfusions

shock index

early mortality

Emergency Medicine and EMS Care