Directed Evolution of a Selective and Sensitive Serotonin Sensor via Machine Learning.

Serotonin plays a central role in cognition and is the target of most pharmaceuticals for psychiatric disorders. Existing drugs have limited efficacy; creation of improved versions will require better understanding of serotonergic circuitry, which has been hampered by our inability to monitor serotonin release and transport with high spatial and temporal resolution. We developed and applied a binding-pocket redesign strategy, guided by machine learning, to create a high-performance, soluble, fluorescent serotonin sensor (iSeroSnFR), enabling optical detection of millisecond-scale serotonin transients. We demonstrate that iSeroSnFR can be used to detect serotonin release in freely behaving mice during fear conditioning, social interaction, and sleep/wake transitions. We also developed a robust assay of serotonin transporter function and modulation by drugs. We expect that both machine-learning-guided binding-pocket redesign and iSeroSnFR will have broad utility for the development of other sensors and in vitro and in vivo serotonin detection, respectively.

Altered TMPRSS2 usage by SARS-CoV-2 Omicron impacts infectivity and fusogenicity.

The SARS-CoV-2 Omicron BA.1 variant emerged in 20211 and has multiple mutations in its spike protein2. Here we show that the spike protein of Omicron has a higher affinity for ACE2 compared with Delta, and a marked change in its antigenicity increases Omicron's evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralizing antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralization. Importantly, the antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared with Delta. The differences in replication were mapped to the entry efficiency of the virus on the basis of spike-pseudotyped virus assays. The defect in entry of Omicron pseudotyped virus to specific cell types effectively correlated with higher cellular RNA expression of TMPRSS2, and deletion of TMPRSS2 affected Delta entry to a greater extent than Omicron. Furthermore, drug inhibitors targeting specific entry pathways3 demonstrated that the Omicron spike inefficiently uses the cellular protease TMPRSS2, which promotes cell entry through plasma membrane fusion, with greater dependency on cell entry through the endocytic pathway. Consistent with suboptimal S1/S2 cleavage and inability to use TMPRSS2, syncytium formation by the Omicron spike was substantially impaired compared with the Delta spike. The less efficient spike cleavage of Omicron at S1/S2 is associated with a shift in cellular tropism away from TMPRSS2-expressing cells, with implications for altered pathogenesis.

Lymphocyte Depleting and Modulating Therapies for Chronic Lung Allograft Dysfunction.

Chronic lung rejection, also called chronic lung allograft dysfunction (CLAD), remains the major hurdle limiting long-term survival after lung transplantation, and limited therapeutic options are available to slow the progressive decline in lung function. Most interventions are only temporarily effective in stabilizing the loss of or modestly improving lung function, with disease progression resuming over time in the majority of patients. Therefore, identification of effective treatments that prevent the onset or halt progression of CLAD is urgently needed. As a key effector cell in its pathophysiology, lymphocytes have been considered a therapeutic target in CLAD. The aim of this review is to evaluate the use and efficacy of lymphocyte depleting and immunomodulating therapies in progressive CLAD beyond usual maintenance immunosuppressive strategies. Modalities used include anti-thymocyte globulin, alemtuzumab, methotrexate, cyclophosphamide, total lymphoid irradiation, and extracorporeal photopheresis, and to explore possible future strategies. When considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin and total lymphoid irradiation appear to offer the best treatment options currently available for progressive CLAD patients. SIGNIFICANCE STATEMENT: Effective treatments to prevent the onset and progression of chronic lung rejection after lung transplantation are still a major shortcoming. Based on existing data to date, considering both efficacy and risk of side effects, extracorporeal photopheresis, anti-thymocyte globulin, and total lymphoid irradiation are currently the most viable second-line treatment options. However, it is important to note that interpretation of most results is hampered by the lack of randomized controlled trials.

Impact of Disease-Associated Mutations on the Deaminase Activity of ADAR1.

The innate immune system relies on molecular sensors to detect distinctive molecular patterns, including viral double-stranded RNA (dsRNA), which triggers responses resulting in apoptosis and immune infiltration. Adenosine Deaminases Acting on RNA (ADARs) catalyze the deamination of adenosine (A) to inosine (I), serving as a mechanism to distinguish self from non-self RNA and prevent aberrant immune activation. Loss-of-function mutations in the ADAR1 gene are one cause of Aicardi Goutières Syndrome (AGS), a severe autoimmune disorder in children. Although seven out of the eight AGS-associated mutations in ADAR1 occur within the catalytic domain of the ADAR1 protein, their specific effects on the catalysis of adenosine deamination remain poorly understood. In this study, we carried out a biochemical investigation of four AGS-causing mutations (G1007R, R892H, K999N, and Y1112F) in ADAR1 p110 and truncated variants. These studies included adenosine deamination rate measurements with two different RNA substrates derived from human transcripts known to be edited by ADAR1 p110 (glioma-associated oncogene homologue 1 (hGli1), 5-hydroxytryptamine receptor 2C (5-HT2cR)). Our results indicate that AGS-associated mutations at two amino acid positions directly involved in stabilizing the base-flipped conformation of the ADAR-RNA complex (G1007R and R892H) had the most detrimental impact on catalysis. The K999N mutation, positioned near the RNA binding interface, altered catalysis contextually. Finally, the Y1112F mutation had small effects in each of the assays described here. These findings shed light on the differential effects of disease-associated mutations on adenosine deamination by ADAR1, thereby advancing our structural and functional understanding of ADAR1-mediated RNA editing.

The use of extracorporeal photopheresis in solid organ transplantation-current status and future directions.

Prevention and management of allograft rejection urgently require more effective therapeutic solutions. Current immunosuppressive therapies used in solid organ transplantation, while effective in reducing the risk of acute rejection, are associated with substantial adverse effects. There is, therefore, a need for agents that can provide immunomodulation, supporting graft tolerance, while minimizing the need for immunosuppression. Extracorporeal photopheresis (ECP) is an immunomodulatory therapy currently recommended in international guidelines as an adjunctive treatment for the prevention and management of organ rejection in heart and lung transplantations. This article reviews clinical experience and ongoing research with ECP for organ rejection in heart and lung transplantations, as well as emerging findings in kidney and liver transplantation. ECP, due to its immunomodulatory and immunosuppressive-sparing effects, offers a potential therapeutic option in these settings, particularly in high-risk patients with comorbidities, infectious complications, or malignancies.

Considerations in gender-affirming hormone therapy in transgender and gender diverse patients undergoing liver transplantation.

Liver transplantation is lifesaving for patients with end-stage liver disease. Similar to the role of transplantation for patients with end-stage liver disease, gender-affirming hormone therapy (GAHT) can be lifesaving for transgender and gender diverse (TGGD) patients who experience gender dysphoria. However, management of such hormone therapy during the perioperative period is unknown and without clear guidelines. Profound strides can be made in improving care for TGGD patients through gender-affirming care and appropriate management of GAHT in liver transplantation. In this article, we call for the transplant community to acknowledge the integral role of GAHT in the care of TGGD liver transplant candidates and recipients. We review the current literature and describe how the transplant community is ethically obligated to address this health care gap. We suggest tangible steps that clinicians may take to improve health outcomes for this minoritized patient population.

miRNA Expression in Fibroblastic Foci within Idiopathic Pulmonary Fibrosis Lungs Reveals Novel Disease-Relevant Pathways.

miRNAs are 22 nucleotides long and belong to a class of noncoding RNAs that plays an important role in regulating gene expression at a post-transcriptional level. Studies show aberrant levels of miRNAs to be associated with profibrotic processes in idiopathic pulmonary fibrosis (IPF). However, most of these studies used whole IPF tissue or in vitro monocultures in which fibrosis was artificially induced. The current study used laser microdissection to collect fibroblastic foci (FF), the key pathologic lesion in IPF, isolated miRNAs, and compared their expression levels with those found in whole IPF lung tissue and/or in vitro cultured fibroblast from IPF or normal lungs. Sequencing libraries were generated, and data generated were bioinformatically analyzed. A total of 18 miRNAs were significantly overexpressed in FF tissue when compared with whole IPF tissue. Of those, 15 were unique to FF. Comparison of FF with cultured IPF fibroblasts also revealed differences in miRNA composition that impacted several signaling pathways. The miRNA composition of FF is both overlapping and distinct from that of whole IPF tissue or cultured IPF fibroblasts and highlights the importance of characterizing FF biology as a phenotypically and functionally discrete tissue microenvironment.

OPTIMAL: An OPTimized Imaging Mass cytometry AnaLysis framework for benchmarking segmentation and data exploration.

Analysis of imaging mass cytometry (IMC) data and other low-resolution multiplexed tissue imaging technologies is often confounded by poor single-cell segmentation and suboptimal approaches for data visualization and exploration. This can lead to inaccurate identification of cell phenotypes, states, or spatial relationships compared to reference data from single-cell suspension technologies. To this end we have developed the "OPTimized Imaging Mass cytometry AnaLysis (OPTIMAL)" framework to benchmark any approaches for cell segmentation, parameter transformation, batch effect correction, data visualization/clustering, and spatial neighborhood analysis. Using a panel of 27 metal-tagged antibodies recognizing well-characterized phenotypic and functional markers to stain the same Formalin-Fixed Paraffin Embedded (FFPE) human tonsil sample tissue microarray over 12 temporally distinct batches we tested several cell segmentation models, a range of different arcsinh cofactor parameter transformation values, 5 different dimensionality reduction algorithms, and 2 clustering methods. Finally, we assessed the optimal approach for performing neighborhood analysis. We found that single-cell segmentation was improved by the use of an Ilastik-derived probability map but that issues with poor segmentation were only really evident after clustering and cell type/state identification and not always evident when using "classical" bivariate data display techniques. The optimal arcsinh cofactor for parameter transformation was 1 as it maximized the statistical separation between negative and positive signal distributions and a simple Z-score normalization step after arcsinh transformation eliminated batch effects. Of the five different dimensionality reduction approaches tested, PacMap gave the best data structure with FLOWSOM clustering out-performing phenograph in terms of cell type identification. We also found that neighborhood analysis was influenced by the method used for finding neighboring cells with a "disc" pixel expansion outperforming a "bounding box" approach combined with the need for filtering objects based on size and image-edge location. Importantly, OPTIMAL can be used to assess and integrate with any existing approach to IMC data analysis and, as it creates .FCS files from the segmentation output and allows for single-cell exploration to be conducted using a wide variety of accessible software and algorithms familiar to conventional flow cytometrists.

Blood consumption in the Role 2 setting: A Department of Defense Trauma Registry analysis.

BACKGROUND: The Role 2 setting represents the most far-forward military treatment facility with limited surgical and holding capabilities. There are limited data to guide recommendations on blood product utilization at the Role 2. We describe the consumption of blood products in this setting. STUDY DESIGN AND METHODS: We analyzed data from 2007 to 2023 from the Department of Defense Trauma Registry (DODTR) that received care at a Role 2. We used descriptive and inferential statistics to characterize the volumes of blood products consumed in this setting. We also performed a secondary analysis of US military, Coalition, and US contractor personnel. RESULTS: Within our initial cohort analysis of 15,581 encounters, 17% (2636) received at least one unit of PRBCs or whole blood, of which 11% received a submassive transfusion, 4% received a massive transfusion, and 1% received a supermassive transfusion. There were 6402 encounters that met inclusion for our secondary analysis. With this group, 5% received a submassive transfusion, 2% received a massive transfusion, and 1% received a supermassive transfusion. CONCLUSIONS: We described volumes of blood products consumed at the Role 2 during recent conflicts. The maximum number of units consumed among survivors exceeds currently recommended available blood supply. Our findings suggest that rapid resupply and cold-stored chain demands may be higher than anticipated in future conflicts.

The employment of resuscitative endovascular balloon occlusion of the aorta in deployed settings.

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been often used in place of open aortic occlusion for management of hemorrhagic shock in trauma. There is a paucity of data evaluating REBOA usage in military settings. STUDY DESIGN AND METHODS: We queried the Department of Defense Trauma Registry (DODTR) for all cases with at least one intervention or assessment available within the first 72 h after injury between 2007 and 2023. We used relevant procedural codes to identify the use of REBOA within the DODTR, and we used descriptive statistics to characterize its use. RESULTS: We identified 17 cases of REBOA placed in combat settings from 2017 to 2019. The majority of these were placed in the operating room (76%) and in civilian patients (70%). A penetrating mechanism caused the injury in 94% of cases with predominantly the abdomen and extremities having serious injuries. All patients subsequently underwent an exploratory laparotomy after REBOA placement, with moderate numbers of patients having spleen, liver, and small bowel injuries. The majority (82%) of included patients survived to hospital discharge. DISCUSSION: We describe 17 cases of REBOA within the DODTR from 2007 to 2023, adding to the limited documentation of patients undergoing REBOA in military settings. We identified patterns of injury in line with previous studies of patients undergoing REBOA in military settings. In this small sample of military casualties, we observed a high survival rate.

A survey of low titer O whole blood use within the trauma quality improvement program registry.

INTRODUCTION: The use of low titer O whole blood (LTOWB) has expanded although it remains unclear how many civilian trauma centers are using LTOWB. METHODS: We analyzed data on civilian LTOWB recipients in the American College of Surgeons Trauma Quality Improvement Program (TQIP) database 2020-2021. Unique facility keys were used to determine the number of centers that used LTOWB in that period. RESULTS: A total of 16,603 patients received LTOWB in the TQIP database between 2020 and 2021; 6600 in 2020, and 10,003 in 2021. The total number of facilities that reported LTOWB use went from 287/779 (37%) in 2020 to 302/795 (38%) in 2021. Between 2020 and 2021, among all level 1-3 designated trauma facilities that report to TQIP LTOWB use increased at level-1 centers (118 to 129), and level-2 centers (81 to 86), but decreased in level-3 facilities (9 to 4). Among pediatric and dual pediatric-adult designated hospitals there was a decrease in the number of pediatric level-1 centers (29 to 28) capable of administering LTOWB. Among centers with either single or dual level-1 trauma center designation with adult centers, the number that administered LTOWB to injured pediatric patients also decreased from 17 to 10, respectively. CONCLUSIONS: There was an increase in the number of facilities transfusing LTOWB between 2020 and 2021. The use of LTOWB is underutilized in children at centers that have it available. These findings inform the expansion of LTOWB use in trauma.

A Split-Lung Ex Vivo Perfusion Model for Time- and Cost-Effective Evaluation of Therapeutic Interventions to the Human Donor Lung.

With the ongoing shortage of donor lungs, ex vivo lung perfusion (EVLP) offers the opportunity for objective assessment and potential therapeutic repair of marginal organs. There is a need for robust research on EVLP interventions to increase the number of transplantable organs. The use of human lungs, which have been declined for transplant, for these studies is preferable to animal organs and is indeed essential if clinical translation is to be achieved. However, experimental human EVLP is time-consuming and expensive, limiting the rate at which promising interventions can be assessed. A split-lung EVLP model, which allows stable perfusion and ventilation of two single lungs from the same donor, offers advantages scientifically, financially and in time to yield results. Identical parallel circuits allow one to receive an intervention and the other to act as a control, removing inter-donor variation between study groups. Continuous hemodynamic and airway parameters are recorded and blood gas, perfusate, and tissue sampling are facilitated. Pulmonary edema is assessed directly using ultrasound, and indirectly using the lung tissue wet:dry ratio. Evans blue dye leaks into the tissue and can quantify vascular endothelial permeability. The split-lung ex vivo perfusion model offers a cost-effective, reliable platform for testing therapeutic interventions with relatively small sample sizes.

Interventions associated with survival after prehospital intubation in the deployed combat setting.

INTRODUCTION: Airway compromise is the second leading cause of potentially preventable death on the battlefield. Prehospital airway management is often unavoidable in a kinetic combat environment and expected to increase in future wars where timely evacuation will be unreliable and air superiority not guaranteed. We compared characteristics of survivors to non-survivors among combat casualties undergoing prehospital airway intubation. MATERIALS AND METHODS: We requested all Department of Defense Trauma Registry (DODTR) encounters during 2007-2023 with documentation of any airway intervention or assessment within the first 72-h after injury. We conducted a retrospective cohort study of all casualties with intubation documented in the prehospital setting. We used descriptive and inferential statistical analysis to compare survivors through 7 days post injury versus non-survivors. We constructed 3 multivariable logistic regression models to test for associations between interventions and 7-day survival after adjusting for injury severity score, mechanism of injury, and receipt of sedatives, paralytics, and blood products. RESULTS: There were 1377 of 48,301 patients with documentation of prehospital intubation in a combat setting. Of these, 1028 (75%) survived through 7 days post injury. Higher proportions of survivors received ketamine, paralytic agents, parenteral opioids, and parenteral benzodiazepines; there was no difference in the proportions of survivors versus non-survivors receiving etomidate. The multivariable models consistently demonstrated positive associations between 7-day survival and receipt of non-depolarizing paralytics and opioid analgesics. CONCLUSIONS: We found an association between non-depolarizing paralytic and opioid receipt with 7-day survival among patients undergoing prehospital intubation. The literature would benefit from future multi-center randomized controlled trials to establish optimal pharmacologic strategies for trauma patients undergoing prehospital intubation.

Characterizing emergency department surgical airway placement in the setting of trauma.

INTRODUCTION: Airway management is a key intervention during the resuscitation of critically ill trauma patients. Emergency surgical airway (ESA) placement is taught as a backup option when endotracheal intubation (ETI) fails. We sought to (1) describe the incidence of the emergency department (ED) ESA, (2) compare ESA versus ETI-only recipients, and (3) determine which factors were associated with receipt of an ESA. METHODS: We searched within the Trauma Quality Improvement Program datasets from 2017 to 2022 for all emergency department surgical airway placement and/or endotracheal intubations recipients. We compared ESA versus ETI-only recipients. RESULTS: From 2017 to 2022, there were 6,477,759 within the datasets, of which 238,128 met inclusion for this analysis. Within that, there were 236,292 ETIs, 2264 ESAs, with 428 (<1 %) having documentation of both. Of the ESAs performed, there were 82 documented in children <15 years of age with the youngest being 1 year of age. The ETI-only group had a lower proportion serious injuries to the head/neck (52 % versus 59 %), face (2 % versus 8 %), and skin (3 % versus 6 %). However, the ETI-only group had a higher proportion of serious injuries to the abdomen (15 % versus 9 %) and the extremities (19 % versus 12 %). Survival at 24-h was higher in the ETI-only group (83 % versus 76 %) as well as survival to discharge (70 % versus 67 %). In the subanaysis of children <15 years (n = 82), 34 % occurred in the 1-4 years age group, 35 % in the 5-9 years age group, and 30 % in the 10-14 years age group. In our multivariable logistic regression analysis, serious injuries to the head/neck (odds ratio [OR] 1.37, 95 % CI 1.23-1.54), face (OR 3.41, 2.83-4.11), thorax (OR 1.19, 1.06-1.33), and skin (OR 1.53, 1.15-2.05) were all associated with receipt of cricothyrotomy. Firearm (OR 3.62, 3.18-4.12), stabbing (2.85, 2.09-3.89), and other (OR 2.85, 2.09-3.89) were associated with receipt of ESA when using collision as the reference variable. CONCLUSIONS: ESA placement is a rarely performed procedure but frequently used as a primary airway intervention in this dataset. Penetrating mechanisms, and injuries to face were most associated with ESA placement. Our findings reinforce the need to maintain this critical airway skill for trauma management.

ADAR activation by inducing a syn conformation at guanosine adjacent to an editing site.

ADARs (adenosine deaminases acting on RNA) can be directed to sites in the transcriptome by complementary guide strands allowing for the correction of disease-causing mutations at the RNA level. However, ADARs show bias against editing adenosines with a guanosine 5' nearest neighbor (5'-GA sites), limiting the scope of this approach. Earlier studies suggested this effect arises from a clash in the RNA minor groove involving the 2-amino group of the guanosine adjacent to an editing site. Here we show that nucleosides capable of pairing with guanosine in a syn conformation enhance editing for 5'-GA sites. We describe the crystal structure of a fragment of human ADAR2 bound to RNA bearing a G:G pair adjacent to an editing site. The two guanosines form a Gsyn:Ganti pair solving the steric problem by flipping the 2-amino group of the guanosine adjacent to the editing site into the major groove. Also, duplexes with 2'-deoxyadenosine and 3-deaza-2'-deoxyadenosine displayed increased editing efficiency, suggesting the formation of a Gsyn:AH+anti pair. This was supported by X-ray crystallography of an ADAR complex with RNA bearing a G:3-deaza dA pair. This study shows how non-Watson-Crick pairing in duplex RNA can facilitate ADAR editing enabling the design of next generation guide strands for therapeutic RNA editing.

Implementing Tourniquet Conversion Guidelines for Civilian EMS and Prehospital Organizations : A Case Report and Review.

Since the first documented use of a tourniquet in 1674, the popularity of tourniquets has waxed and waned. During recent wars and more recently in Emergency Medical Services systems, the tourniquet has been proven to be a valuable tool in the treatment of life-threatening hemorrhage. However, tourniquet use is not without risk, and several studies have demonstrated adverse events and morbidity associated with tourniquet use in the prehospital setting, particularly when left in place for more than 2 h. Consequently, the US military's Committee on Tactical Combat Casualty Care has recommended guidelines for prehospital tourniquet conversion to reduce the risk of adverse events associated with tourniquets once the initial hemorrhage has been controlled. Emergency Medical Services systems that operate in rural, frontier, and austere environments, especially those with transport times to definitive care that routinely exceed 2 h, may consider implementing similar tourniquet conversion guidelines.

Downregulation of MALAT1 is a hallmark of tissue and peripheral proliferative T cells in COVID-19.

T cells play key protective but also pathogenic roles in COVID-19. We studied the expression of long non-coding RNAs (lncRNAs) in COVID-19 T-cell transcriptomes by integrating previously published single-cell RNA sequencing datasets. The long intergenic non-coding RNA MALAT1 was the most highly transcribed lncRNA in T cells, with Th1 cells demonstrating the lowest and CD8+ resident memory cells the highest MALAT1 expression, amongst CD4+ and CD8+ T-cells populations, respectively. We then identified gene signatures that covaried with MALAT1 in single T cells. A significantly higher number of transcripts correlated negatively with MALAT1 than those that correlated. Enriched functional annotations of the MALAT1- anti-correlating gene signature included processes associated with T-cell activation such as cell division, oxidative phosphorylation, and response to cytokine. The MALAT1 anti-correlating gene signature shared by both CD4+ and CD8+ T-cells marked dividing T cells in both the lung and blood of COVID-19 patients. Focussing on the tissue, we used an independent patient cohort of post-mortem COVID-19 lung samples and demonstrated that MALAT1 suppression was indeed a marker of MKI67+ proliferating CD8+ T cells. Our results reveal MALAT1 suppression and its associated gene signature are a hallmark of human proliferating T cells.

A Contemporary Analysis of Combat-related Urological Injuries: Data From the Department of Defense Trauma Registry.

PURPOSE: There has been little to no literature published on combat-related genitourinary injuries beyond 2013. With the goal of enhancing medical readiness prior to deployment and making recommendations to improve the long-term rehabilitation of service members as they become civilians, we sought to describe the incidence of combat-related genitourinary injuries and interventions from January 1, 2007, to March 17, 2020. MATERIALS AND METHODS: We conducted a retrospective analysis of the Department of Defense Trauma Registry, which is a prospectively maintained database, for the time between 2007 and 2020. We used predefined search criteria to primarily identify any casualties that arrived at a military treatment facility with urological-based injuries. RESULTS: The registry contained 25,897 adult casualties, of which 7.2% sustained urological injuries. The median age was 25. Explosive injuries (64%) and firearms (27%) predominated. The median injury severity score was 18 (IQR 10-29). Most patients survived until hospital discharge (94%). The most frequently injured organs were the scrotum (60%), testes (53%), penis (30%), and kidneys (30%). Massive transfusion protocols were activated in 35% of all patients who sustained a urological injury and accounted for 28% of all protocols between 2007 and 2020. CONCLUSIONS: The incidence of genitourinary trauma persistently increased for both military and civilian personnel as the U.S. remained actively engaged in major military conflicts during this period. Patients with genitourinary trauma in this data set were often associated with high injury severity scores and required an increased number of immediate and long-term resources for survival and rehabilitation.

A prospective assessment of the time required to obtain one unit of fresh whole blood by civilian phlebotomists and Army laboratory technicians (68 K).

BACKGROUND: Resuscitation with blood products improves survival after major hemorrhage. Blood product administration at or near the point-of-injury (POI) amplifies this benefit. Size, weight, and cold-chain management challenges all limit the amount of blood medics can carry. Warm fresh whole blood (WFWB) transfusions from a pre-screened donor within the unit represent an alternative source of blood at the POI. We measured the time required for civilian and Army technicians performing phlebotomy frequently to obtain one unit of blood to serve as a goal metric for combat medics being trained in this skill. METHODS: We gathered demographic and experience data along with proportion of first intravenous cannulation attempt success, time to blood flow initiated, and time to unit draw complete. RESULTS: We prospectively enrolled 12 civilian phlebotomy technicians and 10 Army laboratory technicians performing whole blood collections on 50 and 68 donors respectively. The mean time from setup to needle insertion was 3.7 min for civilians versus 4.2 min for Army technicians. The mean time from blood flowing to the bag being full was 10.7 min versus 8.4 min for civilians versus Army technicians respectively. The mean bag weights were 514 g versus 522 g. First-pass intravenous cannulation success was 96% versus 98% respectively. CONCLUSIONS: We found a high first intravenous cannulation attempt success among both the civilian and Army technicians. Medians times were <5 min to obtain venipuncture and <11 min to obtain one unit. These findings provide time-based benchmarks for potential use during transfusion training among military medics.

A prospective assessment of the medic autologous blood transfusion skills for field transfusion preparation.

BACKGROUND: Data demonstrate the benefit of blood product administration near point-of-injury (POI). Fresh whole blood transfusion from a pre-screened donor provides a source of blood at the POI when resources are constrained. We captured transfusion skills data for medics performing autologous blood transfusion training. METHODS: We conducted a prospective, observational study of medics with varying levels of experience. Inexperienced medics were those with minimal or no reported experience learning the autologous transfusion procedures, versus reported experience among special operations medics. When available, medics were debriefed after the procedure for qualitative feedback. We followed them for up to 7 days for adverse events. RESULTS: The median number of attempts for inexperienced and experienced medics was 1 versus 1 (interquartile range 1-1 for both, p = .260). The inexperienced medics had a slower median time to needle venipuncture access for the donation of 7.3 versus 1.5 min, needle removal after clamping time of 0.3 versus 0.2 min, time to bag preparation of 1.9 versus 1.0 min, time to IV access for reinfusion of 6.0 versus 3.0 min, time to transfusion completion of 17.3 versus 11.0 min, and time to IV removal of 0.9 versus 0.3 min (all p < .05). We noted one administrative safety event in which an allogeneic transfusion occurred. No major adverse events occurred. Qualitative data saturated around the need for quarterly training. CONCLUSIONS: Inexperienced medics have longer procedure times when training autologous whole blood transfusion skills. This data will help establish training measures of performance for skills optimization when learning this procedure.