Prehospital Surgical Cricothyrotomy in a Ground-Based 9-1-1 EMS System: A Retrospective Review.

BACKGROUND: Airway management is a cornerstone in the prehospital care of critically ill or injured patients. Surgical cricothyrotomy offers a rapid and effective solution when oxygenation and ventilation fail using less-invasive techniques. However, the exact indications, incidence, and success of prehospital surgical cricothyrotomy are unknown, with variable rates reported in the literature. This study aimed to examine prehospital indications and success rates for surgical cricothyrotomy within a large, suburban, ground-based Emergency Medical Services (EMS) system. METHODS: This is a retrospective analysis of 31 patients who underwent paramedic performed surgical cricothyrotomy from 2012 through 2022. Key demographic parameters were analyzed, including the incidence of cardiac arrest, call type (trauma versus medical), initial airway management attempts, number of endotracheal intubation (ETI) attempts before surgical airway, and average time to the establishment of a surgical airway in relation to the number of ETI attempts. Surgical cricothyrotomy success was defined as the acquisition of four-phase end-tidal capnography reading. The primary data sources were the EMS electronic medical records, and descriptive statistics were calculated. RESULTS: A total of 31 patients were included in the final analysis. Of those who received a surgical cricothyrotomy, 42% (13/31) occurred in the trauma setting, while 58% (18/31) were medical calls. In all patients who underwent surgical cricothyrotomy, the median (IQR) time to the procedure was 17 minutes (IQR = 11-24). In trauma patients, the median time to surgical cricothyrotomy was 12 minutes (IQR = 9-19) versus 19 minutes (IQR = 14-33) in medical patients. End-tidal carbon dioxide (ETCO2) detection and placement success was confirmed in 94% (29/31) of patients. Endotracheal intubation was attempted in 55% (17/31) before subsequent surgical cricothyrotomy, with 29% (9/31) receiving more than one ETI attempt. The median time to surgical cricothyrotomy when multiple prior intubation attempts occurred was 33 minutes (IQR = 23-36) compared to 14.5 minutes (IQR = 6-19) in patients without a preceding intubation attempt. CONCLUSION: Prehospital surgical airway can be performed by paramedics with a high degree of success. Identification of the need for surgical cricothyrotomy should be determined as soon as possible to allow for rapid securement of the airway and to ensure adequate oxygenation and ventilation.

Isothermal titration calorimetry and surface plasmon resonance methods to probe protein-protein interactions.

Isothermal titration calorimetry (ITC) and surface plasmon resonance (SPR) are two commonly used methods to probe biomolecular interactions. ITC can provide information about the binding affinity, stoichiometry, changes in Gibbs free energy, enthalpy, entropy, and heat capacity upon binding. SPR can provide information about the association and dissociation kinetics, binding affinity, and stoichiometry. Both methods can determine the nature of protein-protein interactions and help understand the physicochemical principles underlying complex biochemical pathways and communication networks. This methods article discusses the practical knowledge of how to set up and troubleshoot these two experiments with some examples.

Safety of prehospital intravenous bolus dose nitroglycerin in patients with acute pulmonary edema: A 4-year review.

Background: Intravenous nitrates are a primary therapy for hypertensive congestive heart failure (CHF) with acute pulmonary edema (APE) in the hospital setting. Historically, sublingual nitrates are the mainstay of emergency medical services (EMS) pharmacologic therapy for these patients. We aimed to evaluate the safety of prehospital bolus dose intravenous nitroglycerin in patients with APE. Methods: This is a retrospective evaluation of EMS data between March 15, 2018, and March 15, 2022, where CHF with APE was suspected and bolus-dose intravenous nitroglycerin was administered. Protocol inclusion criteria were hypertension (systolic blood pressure [SBP] >160 mmHg) and acute respiratory distress, with a presumption of decompensated CHF with APE. These patients received 1 mg intravenous nitroglycerin, with the option to repeat once for ongoing distress if the SBP remained >160 mmHg. The primary outcomes were adverse events, defined as hypotension (SBP <90 mmHg), syncope, vomiting, or dysrhythmia. Results: The final analysis included 235 patients. In patients receiving intravenous bolus nitroglycerin, the median (interquartile range [IQR]) initial and final EMS SBP values decreased from 198 mmHg (180-218) to 168 (148-187), respectively. The median (IQR) pulse decreased from 108 (92-125) to 103 (86-119), and the median oxygen saturation increased from 89% (82-95) to 98% (96-99). Three episodes (1.3%) of asymptomatic hypotension occurred, and none required intervention. Conclusion: This study supports a favorable safety profile for prehospital bolus-dose intravenous nitroglycerin for decompensated CHF with APE. Blood pressure, heart rate, and oxygen saturation improvements are also demonstrated. Further, prospective studies are needed to confirm these findings.

Biophysical evolution of the receptor-binding domains of SARS-CoVs.

With hundreds of coronaviruses (CoVs) identified in bats that can infect humans, it is essential to understand how CoVs that affected the human population have evolved. Seven known CoVs have infected humans, of which three CoVs caused severe disease with high mortalities: severe acute respiratory syndrome (SARS)-CoV emerged in 2002, Middle East respiratory syndrome-CoV in 2012, and SARS-CoV-2 in 2019. SARS-CoV and SARS-CoV-2 belong to the same family, follow the same receptor pathway, and use their receptor-binding domain (RBD) of spike protein to bind to the angiotensin-converting enzyme 2 (ACE2) receptor on the human epithelial cell surface. The sequence of the two RBDs is divergent, especially in the receptor-binding motif that directly interacts with ACE2. We probed the biophysical differences between the two RBDs in terms of their structure, stability, aggregation, and function. Since RBD is being explored as an antigen in protein subunit vaccines against CoVs, determining these biophysical properties will also aid in developing stable protein subunit vaccines. Our results show that, despite RBDs having a similar three-dimensional structure, they differ in their thermodynamic stability. RBD of SARS-CoV-2 is significantly less stable than that of SARS-CoV. Correspondingly, SARS-CoV-2 RBD shows a higher aggregation propensity. Regarding binding to ACE2, less stable SARS-CoV-2 RBD binds with a higher affinity than more stable SARS-CoV RBD. In addition, SARS-CoV-2 RBD is more homogenous in terms of its binding stoichiometry toward ACE2 compared to SARS-CoV RBD. These results indicate that SARS-CoV-2 RBD differs from SARS-CoV RBD in terms of its stability, aggregation, and function, possibly originating from the diverse receptor-binding motifs. Higher aggregation propensity and decreased stability of SARS-CoV-2 RBD warrant further optimization of protein subunit vaccines that use RBD as an antigen by inserting stabilizing mutations or formulation screening.

Prehospital Treatment of Benzodiazepine-Resistant Pediatric Status Epilepticus with Parenteral Ketamine: A Case Series.

We report the initial six pediatric patients treated with ketamine for benzodiazepine-resistant status epilepticus in an urban, ground-based emergency medical services (EMS) system. Evidence for ketamine as a second-line agent for both adult and pediatric refractory seizure activity in the hospital setting has increased over the past decade. The availability of an inexpensive and familiar second-line prehospital anti-epileptic drug option is extremely desirable. We believe these initial data demonstrate promising seizure control effects without significant respiratory depression, indicating a potential role for ketamine in the EMS treatment of pediatric benzodiazepine-refractory seizures.

Nebulized Ketamine for Analgesia in the Prehospital Setting: A Case Series.

We report the initial seven patients treated with nebulized ketamine for moderate to severe pain, via breath-actuated nebulizer, in an urban, ground-based emergency medical services (EMS) system. Ketamine for analgesia in the emergency setting has become widespread over the past decade. The addition of a non-parenteral, inexpensive, and well-tolerated ketamine delivery option is extremely desirable. We believe these initial data demonstrate promising pain reduction coupled with minimal side effects, indicating a potential role for nebulized ketamine in EMS.

Treatment of Presumed Hyperkalemia in the Prehospital Setting.

INTRODUCTION: Hyperkalemia (HK) is common and potentially a life-threatening condition. If untreated, HK can progress to ventricular arrhythmia and cardiac arrest. Early treatment reduces mortality in HK. This study evaluates a novel protocol for identification and empiric management of presumed HK in the prehospital setting. METHODS: This was a retrospective, observational chart review of a single, large, suburban Emergency Medical Services (EMS) system. Patients treated for presumed HK, with both a clinical concern for HK and electrocardiogram (ECG) changes consistent with HK, from February 2018 through February 2021 were eligible for inclusion. Patients were excluded if found to be in cardiac arrest on EMS arrival. Empiric treatment of HK included administration of calcium, sodium bicarbonate, and albuterol. Post-treatment, patients were placed on cardiac monitoring and adverse events recorded enroute to receiving hospital. Protocol compliance was assessed by two independent reviewers. Serum potassium (K) level was obtained from hospital medical records. RESULTS: A total of 582 patients were treated for HK, of which 533 patients were excluded due to cardiac arrest prior to EMS arrival. The remaining 48 patients included in the analysis had a mean age of 56 (SD = 20) years and were 60.4% (n = 29) male with 77.1% (n = 37) Caucasian, 10.4% (n = 5) African American, and 12.5% (n = 6) Hispanic. Initial blood draw at the receiving facilities showed K >5.0mEq/L in 22 (45.8%), K of 3.5-5.0mEq/L in 23 (47.9%), and K <3.5mEq/L in three patients (6.3%). Independent review of the EMS ECG found the presence of hyperkalemic-related change in 43 (89.6%) cases, and five (10.4%) patients did not meet criteria for treatment due to lack of either appropriate ECG findings or clinical suspicion. No episodes of unstable tachyarrhythmia or cardiac arrest occurred during EMS treatment or transport. CONCLUSION: The study evaluated a novel protocol for detecting and managing HK in the prehospital setting. It is feasible for EMS crews to administer this protocol, although a larger study is needed to make the results generalizable.

Antibody-Dependent Complement Responses toward SARS-CoV-2 Receptor-Binding Domain Immobilized on "Pseudovirus-like" Nanoparticles.

Many aspects of innate immune responses to SARS viruses remain unclear. Of particular interest is the role of emerging neutralizing antibodies against the receptor-binding domain (RBD) of SARS-CoV-2 in complement activation and opsonization. To overcome challenges with purified virions, here we introduce "pseudovirus-like" nanoparticles with ∼70 copies of functional recombinant RBD to map complement responses. Nanoparticles fix complement in an RBD-dependent manner in sera of all vaccinated, convalescent, and naïve donors, but vaccinated and convalescent donors with the highest levels of anti-RBD antibodies show significantly higher IgG binding and higher deposition of the third complement protein (C3). The opsonization via anti-RBD antibodies is not an efficient process: on average, each bound antibody promotes binding of less than one C3 molecule. C3 deposition is exclusively through the alternative pathway. C3 molecules bind to protein deposits, but not IgG, on the nanoparticle surface. Lastly, "pseudovirus-like" nanoparticles promote complement-dependent uptake by granulocytes and monocytes in the blood of vaccinated donors with high anti-RBD titers. Using nanoparticles displaying SARS-CoV-2 proteins, we demonstrate subject-dependent differences in complement opsonization and immune recognition.

Convergent Evolution of Multiple Mutations Improves the Viral Fitness of SARS-CoV-2 Variants by Balancing Positive and Negative Selection.

Multiple mutations have been seen to undergo convergent evolution in SARS-CoV-2 variants of concern. One such evolution occurs in Beta, Gamma, and Omicron variants at three amino acid positions K417, E484, and N501 in the receptor binding domain of the spike protein. We examined the physical mechanisms underlying the convergent evolution of three mutations K417T/E484K/N501Y by delineating the individual and collective effects of mutations on binding to angiotensin converting enzyme 2 receptor, immune escape from neutralizing antibodies, protein stability, and expression. Our results show that each mutation serves a distinct function that improves virus fitness supporting its positive selection, even though individual mutations have deleterious effects that make them prone to negative selection. Compared to the wild-type, K417T escapes Class 1 antibodies and has increased stability and expression; however, it has decreased receptor binding. E484K escapes Class 2 antibodies; however, it has decreased receptor binding, stability, and expression. N501Y increases receptor binding; however, it has decreased stability and expression. When these mutations come together, the deleterious effects are mitigated due to the presence of compensatory effects. Triple mutant K417T/E484K/N501Y has increased receptor binding, escapes both Class 1 and Class 2 antibodies, and has similar stability and expression as that of the wild-type. These results show that the convergent evolution of multiple mutations enhances viral fitness on different fronts by balancing both positive and negative selection and improves the chances of selection of mutations together.

Biophysical Fitness Landscape of the SARS-CoV-2 Delta Variant Receptor Binding Domain.

Among the five known SARS-CoV-2 variants of concern, Delta is the most virulent leading to severe symptoms and increased mortality among infected people. Our study seeks to examine how the biophysical parameters of the Delta variant correlate to the clinical observations. Receptor binding domain (RBD) is the first point of contact with the human host cells and is the immunodominant form of the spike protein. Delta variant RBD contains two novel mutations L452R and T478K. We examined the effect of single as well as the double mutations on RBD expression in human Expi293 cells, RBD stability using urea and thermal denaturation, and RBD binding to angiotensin converting enzyme 2 (ACE2) receptor and to neutralizing antibodies using isothermal titration calorimetry. Delta variant RBD showed significantly higher expression compared to the wild-type RBD, and the increased expression is due to L452R mutation. Despite their non-conservative nature, none of the mutations significantly affected RBD structure and stability. All mutants showed similar binding affinity to ACE2 and to Class 1 antibodies (CC12.1 and LY-CoV016) as that of the wild-type. Delta double mutant L452R/T478K showed no binding to Class 2 antibodies (P2B-2F6 and LY-CoV555) and a hundred-fold weaker binding to a Class 3 antibody (REGN10987), and the decreased antibody binding is determined by the L452R mutation. These results indicate that the immune escape from neutralizing antibodies, rather than increased receptor binding, is the main biophysical parameter that determined the fitness landscape of the Delta variant RBD.

Feasibility of prehospital esmolol for refractory ventricular fibrillation.

Background: Esmolol may increase survival for patients with refractory ventricular fibrillation (RVF); however, information related to esmolol use in the prehospital environment is limited. We aimed to assess the feasibility of prehospital bolus dose esmolol for patients with RVF treated by a high-volume, ground-based emergency medical services (EMS) agency. Methods:  Esmolol (0.5 mg/kg single bolus) was added to the RVF protocol on December 10, 2018. Feasibility was defined as esmolol administration in >75% of RVF cases. Secondarily, we compared the proportion of patients with prehospital return of spontaneous circulation (ROSC), 24-hour survival, and survival to hospital discharge during the intervention period (December 10, 2018-June 10, 2020) to a historical control period (June 10, 2017-December 9, 2018) using chi-square tests. Results: Before the protocol change, 63 patients with RVF were identified. After esmolol was added, 70 patients with RVF were identified and 61 (87%) received esmolol. Prehospital ROSC was higher in the esmolol group compared to the historical control group, though statistical significance was not reached (38% versus 24%, P = 0.09). Overall, few patients survived to 24 hours (esmolol n = 15, pre-esmolol n = 16) and fewer survived to hospital discharge (esmolol n = 5, pre-esmolol n = 5), precluding stable statistical comparisons. Conclusion: Collectively, these findings suggest that EMS clinicians are able to accurately identify RVF and administer esmolol in the prehospital setting and that ROSC may be increased. Further large-scale studies are needed to determine the effect of prehospital esmolol for RVF as it relates to neurologically intact hospital discharge.

Prehospital Sinus Node Dysfunction and Asystole in a Previously Healthy Patient with COVID-19.

We report a case of a previously healthy 47-year-old female with syncope due to multiple episodes of nodal dysfunction and asystole. During these brief episodes, she was hypoxic in the mid-80's as a result of COVID-19 pneumonia. The patient was admitted and treated for viral pneumonia and found to have normal electrocardiograms (ECG's), normal troponin levels and a normal echocardiogram during her hospital stay. As she recovered from COVID-19, no further episodes of bradycardia or bradyarrhythmia were noted. This case highlights a growing body of evidence that arrhythmias, specifically bradycardia, should be anticipated by prehospital providers as a potential cardiac complication of SARS-CoV-2 infection.

Association between sleep characteristics, ideal cardiovascular health, and systemic inflammation, NHANES 2017-2018.

There is conflicting evidence regarding the associations between sleep deprivation and inflammatory biomarkers indicative of cardiovascular disease risk, such as high-sensitivity C-reactive protein (hsCRP). The association between sleep habits and hsCRP was quantified in a nationally representative sample of adults in the United States and mediation by ideal cardiovascular health metrics was explored. A cross-sectional analysis of cardiovascular disease-free participants aged 20-79 years from the 2017-2018 National Health and Nutrition Examination Survey was conducted. The primary exposures were self-reported sleep duration, sleep debt (difference between the average weekday and weekend sleep duration), and ideal cardiovascular health (11-14 points). The primary outcome was hsCRP (high-risk ≥ 3.0 mg/L). Multivariable robust Poisson models were used to estimate prevalence ratios after multiple imputation. A subgroup analysis of shift workers was also conducted. Of 4027 participants included (mean age 46 years; 52% female; 41% shift workers), the prevalence of sleeping <6 h on weekdays was 9%, with 40% sleeping ≥9 h on weekends. One-quarter had a high (≥2 h) sleep debt, 82% had poor cardiovascular health, and 34% had high-risk hsCRP. There were no significant associations between weekday sleep duration or sleep debt with high-risk hsCRP, even among shift workers. Mediation analysis was not conducted. Ideal cardiovascular health was associated with a lower prevalence of high-risk hsCRP (prevalence ratios, 0.60, 95% CI, 0.48-0.75). The lack of significant associations suggests a complex interrelationship of hsCRP with factors beyond sleep duration. Examination of populations at highest risk of chronic sleep deprivation could help to elucidate the association with systemic inflammation-related outcomes.

Harnessing Pseudomonas protegens to Control Bacterial Panicle Blight of Rice.

Bacterial panicle blight of rice is a seedborne disease caused by the bacterium Burkholderia glumae. This disease has affected rice production worldwide and its effects are likely to become more devastating with the continuous increase in global temperatures, especially during the growing season. The bacterium can cause disease symptoms in different tissues and at different developmental stages. In reproductive stages, the bacterium interferes with grain development in the panicles and, as a result, directly affects rice yield. Currently, there are no methods to control the disease because chemical control is not effective and completely resistant cultivars are not available. Thus, a promising approach is the use of antagonistic microorganisms. In this work, we identified one strain of Pseudomonas protegens and one strain of B. cepacia with antimicrobial activity against B. glumae in vitro and in planta. We further characterized the antimicrobial activity of P. protegens and found that this activity is associated with bacterial secretions. Cell-free secretions from P. protegens inhibited the growth of B. glumae in vitro and also prevented B. glumae from causing disease in rice. Although the specific molecules associated with these activities have not been identified, these findings suggest that the secreted fractions from P. protegens could be harnessed as biopesticides to control bacterial panicle blight of rice.

Prehospital Efficacy and Adverse Events Associated with Bolus Dose Epinephrine in Hypotensive Patients During Ground-Based EMS Transport.

BACKGROUND: The utility and efficacy of bolus dose vasopressors in hemodynamically unstable patients is well-established in the fields of general anesthesia and obstetrics. However, in the prehospital setting, minimal evidence for bolus dose vasopressor use exists and is primarily limited to critical care transport use. Hypotensive episodes, whether traumatic, peri-intubation-related, or septic, increase patient mortality. The purpose of this study is to assess the efficacy and adverse events associated with prehospital bolus dose epinephrine use in non-cardiac arrest, hypotensive patients treated by a single, high-volume, ground-based Emergency Medical Services (EMS) agency. METHODS: This is a retrospective, observational study of all non-cardiac arrest EMS patients treated for hypotension using bolus dose epinephrine from September 12, 2018 through September 12, 2019. Inclusion criteria for treatment with bolus dose epinephrine required a systolic blood pressure (SBP) measurement <90mmHg. A dose of 20mcg every two minutes, as needed, was allowed per protocol. The primary data source was the EMS electronic medical record. RESULTS: Forty-two patients were treated under the protocol with a median (IQR) initial SBP immediately prior to treatment of 78mmHg (65-86) and a median (IQR) initial mean arterial pressure (MAP) of 58mmHg (50-66). The post-bolus SBP and MAP increased to 93mmHg (75-111) and 69mmHg (59-83), respectively. The two most common patient presentations requiring protocol use were altered mental status (55%) and respiratory failure (31%). Over one-half of the patients treated required both advanced airway management (62%) and multiple bolus doses of vasopressor support (55%). A single episode of transient severe hypertension (SBP>180mmHg) occurred, but there were no episodes of unstable tachyarrhythmia or cardiac arrest while en route or upon arrival to the receiving hospitals. CONCLUSION: These preliminary data suggest that the administration of bolus dose epinephrine may be effective at rapidly augmenting hypotension in the prehospital setting with a minimal incidence of adverse events. Paramedic use of bolus dose epinephrine successfully increased SBP and MAP without clinically significant side effects. Prospective studies with larger sample sizes are needed to further investigate the effects of prehospital bolus dose epinephrine on patient morbidity and mortality.

Feasibility, Effectiveness and Safety of Prehospital Intravenous Bolus Dose Nitroglycerin in Patients with Acute Pulmonary Edema.

Introduction: The necessity of rapid preload and afterload reduction in patients with decompensated congestive heart failure (CHF) and acute pulmonary edema (APE) is well established. In the hospital setting, intravenous (IV) nitroglycerin demonstrates improved patient morbidity and mortality. However, prehospital treatment is typically limited to sublingual nitroglycerin at doses that often do not affect afterload. In this study, we assessed feasibility, safety and effectiveness of prehospital IV bolus nitroglycerin in decompensated CHF patients with APE. Methods: This was a retrospective chart review of all emergency medical services (EMS) and ED patient care records of subjects treated for presumed decompensated CHF with APE with bolus-dose IV nitroglycerin between March 15, 2018 and March 15, 2019 by a large, suburban, county-based EMS service in Texas. Inclusion criteria for treatment included both hypertension (systolic blood pressure [SBP] > 160 mmHg) and acute respiratory distress with a paramedic clinical impression of decompensated CHF with APE. Treatment consisted of a 1 mg nitroglycerin bolus, repeated in 5 minutes if SBP > 160 mmHg. Results: During the study period, 48 patients were treated with IV bolus nitroglycerin. Initially, the median (IQR) SBP was 211.0 mmHg (190.0-229.5), 5-minutes post IV NTG was 177.0 mmHg (155.0-199.0), and upon ED arrival was 181.5 mmHg (157.0-207.0). 5 minutes after IV nitroglycerin, the median pulse decreased from 113 (96-124) to 103 (85-117) beats per minute and the median oxygen saturation increased from 86% (74-89) to 98% (96-99). Based on hospital records review, 45/48 (94%) of patients treated with IV nitroglycerin were found to have CHF with APE. A single episode of transient hypotension, which resolved without treatment, did occur during EMS transport. Conclusion: This case series found that patients who were treated by paramedics with IV NTG had improved systolic blood pressure and oxygen saturation upon ED arrival as compared to their initial presentation. Over 90% of these patients were correctly identified by paramedics as having CHF with APE based on ED evaluation. Only one patient had an adverse event, which was transient hypotension that did not require intervention.

Performance of the RACE Score for the Prehospital Identification of Large Vessel Occlusion Stroke in a Suburban/Rural EMS Service.

Introduction: Emergency Medical Services (EMS) providers may identify and preferentially transport patients experiencing large vessel occlusion (LVO) stroke to appropriate treatment centers. The Rapid Arterial oCclusion Evaluation (RACE) scale was created for prehospital LVO detection, yet few studies have evaluated its function in real-world EMS settings. Our objective was to assess the prehospital performance of the RACE scale for detecting LVO stroke following implementation at a large suburban/rural agency in the United States. Methods: In this retrospective analysis, all 9-1-1 patients with an EMS provider primary or secondary impression of stroke treated by the agency between June 1, 2016 and November 1, 2017 were eligible for inclusion. Patient data were abstracted using a standardized form completed by receiving hospitals. Performance for LVO detection at each RACE cutoff value was evaluated using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). A receiver operating characteristic (ROC) curve was used to evaluate the discrimination of the RACE scale overall. A secondary analysis of RACE for patients experiencing strokes best treated at comprehensive stroke centers (LVO and intracerebral hemorrhage [ICH]) was conducted. Results: There were 440 patients with a documented RACE score and hospital outcome data included in the analysis. About half (51%, n = 220) were female and the median age was 70 years (IQR: 59-81). Last known well time was under 4.5 hours for 76% of patients (n = 261). Over half (61%, n = 269) had a hospital discharge diagnosis of stroke and 64/440 (15%) were classified as LVO. The ROC curve demonstrated adequate discrimination with a c-statistic of 0.72. Performance for identifying LVO in the prehospital setting was greatest for RACE scores ≥5 with a sensitivity of 66% and specificity of 72%, PPV of 29%, and NPV of 93%. A RACE score ≥5 for both LVO and ICH demonstrated sensitivity: 63%, specificity: 77%, PPV: 47% and NPV: 86%. Conclusion: The RACE scale demonstrated acceptable discrimination, yet the sensitivity and positive predictive value were lower in this cohort of EMS professionals in the United States than in the original validation study conducted in Spain. Further work is needed to determine the optimal prehospital screening tool for identification of LVO.

Emergency Medical Services Simple Thoracostomy for Traumatic Cardiac Arrest: Postimplementation Experience in a Ground-based Suburban/Rural Emergency Medical Services Agency.

BACKGROUND: Tube thoracostomy has long been the standard of care for treatment of tension pneumothorax in the hospital setting yet is uncommon in prehospital care apart from helicopter emergency medical services. OBJECTIVE: We aimed to evaluate the performance of simple thoracostomy (ST) for patients with traumatic cardiac arrest and suspected tension pneumothorax. METHODS: We conducted a retrospective case series of consecutive patients with traumatic cardiac arrest where simple thoracostomy was used during the resuscitation effort. Data were abstracted from our Zoll emergency medical record (Zoll Medical Corp., Chelmsford, MA) for patients who received the procedure between June 1, 2013 and July 1, 2017. We collected general descriptive characteristics, procedural success, presence of air or blood, and outcomes for each patient. RESULTS: During the study period we performed ST on 57 patients. The mean age was 41 years old (range 15-81 years old) and 83% were male. Indications included 40 of 57 (70%) blunt trauma and 17 of 57 (30%) penetrating trauma. The presenting rhythm was pulseless electrical activity 65%, asystole 26%, ventricular tachycardia/fibrillation 4%, and nonrecorded 5%. Eighteen of 57 (32%) had air return, 14 of 57 (25%) return of spontaneous circulation, with 6 of 57 (11%) surviving to 24 h and 4 of 57 (7%) discharged from the hospital neurologically intact. Of the survivors, all were blunt trauma mechanism with initial rhythms of pulseless electrical activity. There were no reported medic injuries. CONCLUSIONS: Our data show that properly trained paramedics in ground-based emergency medical services were able to safely and effectively perform ST in patients with traumatic cardiac arrest. We found a significant (32%) presence of pneumothorax in our sample, which supports previously reported high rates in this patient population.