Initial Validity Evidence for the American Board of Emergency Medicine Emergency Medical Services Certification Examination.

OBJECTIVES: The American Board of Emergency Medicine (ABEM) Emergency Medical Services Medicine (EMS) subspecialty was approved by the American Board of Medical Specialties on September 23, 2010. Subspecialty certification in EMS was contingent on two key elements-completing Accreditation Council for Graduate Medical Education (ACGME)-accredited EMS training and passing the subspecialty certification examination developed by ABEM. The first EMS certification examination was offered in October 2013. Meaningful certification requires rigorous assessment. In this instance, the EMS certification examination sought to embrace the tenets of validity, reliability, and fairness. For the purposes of this report, the sources of validity evidence were anchored on the EMS core content, the examination development process, and the association between fellowship training and passing the certification examination. METHODS: We chose to use validity evidence that included: 1) content validity (based on the EMS core content); 2) response processes (test items required intended cognitive processes); 3) internal structure supported by the internal relationships among items; 4) relations to other variables, specifically the association between examination performance and ACGME-accredited fellowship training; and 5) the consequences of testing. RESULTS: There is strong content validity evidence for the EMS examination based on the core content and its detailed development process. The core content and supporting job-task analysis was also used to define the examination blueprint. Internal structure support was evidenced by Cronbach's coefficient alpha, which ranged from 0.82 to 0.92. Physicians who completed ACGME-accredited EMS fellowship training were more likely to pass the EMS certification examination (chi square, p < 0.0001; Cramér's, V = 0.24). Finally, there were two sources of consequential validity evidence-use of test results to determine certification and use of the resulting certificate. CONCLUSIONS: There is substantial and varied validity evidence to support the use of the EMS certifying examination in making summative decisions to award certification in EMS. Of note, there was a statistically significant association between ACGME-accredited fellowship training and passing the examination.

Fixed dose ketamine for prehospital management of hyperactive delirium with severe agitation.

INTRODUCTION: Patients exhibiting signs of hyperactive delirium with severe agitation (HDSA) may require sedating medications for stabilization and safe transport to the hospital. Determining the patient's weight and calculating the correct weight-based dose may be challenging in an emergency. A fixed dose ketamine protocol is an alternative to the traditional weight-based administration, which may also reduce dosing errors. The objective of this study was to evaluate the frequency and characteristics of adverse events following pre-hospital ketamine administration for HDSA. METHODS: Emergency Medical Services (EMS) records from four agencies were searched for prehospital ketamine administration. Cases were included if a 250 mg dose of ketamine was administered on standing order to an adult patient for clinical signs consistent with HDSA. Protocols allowed for a second 250 mg dose of ketamine if the first dose was not effective. Both the 250 mg initial dose and the total prehospital dose were analyzed for weight based dosing and adverse events. RESULTS: Review of 132 cases revealed 60 cases that met inclusion criteria. Patients' median weight was 80 kg (range: 50-176 kg). No patients were intubated by EMS, one only requiring suction, three required respiratory support via bag valve mask (BVM). Six (10%) patients were intubated in the emergency department (ED) including the three (5%) supported by EMS via BVM, three (5%) others who were sedated further in the ED prior to requiring intubation. All six patients who were intubated were discharged from the hospital with a Cerebral Performance Category (CPC) 1 score. The weight-based dosing equivalent for the 250 mg initial dose (OR: 2.62, CI: 0.67-10.22) and the total prehospital dose, inclusive of the 12 patients that were administered a second dose, (OR: 0.74, CI: 0.27, 2.03), were not associated with the need for intubation. CONCLUSION: The 250 mg fixed dose of ketamine was not >5 mg/kg weight-based dose equivalent for all patients in this study. Although a second 250 mg dose of ketamine was permitted under standing orders, only 12 (20%) of the patients were administered a second dose, none experienced an adverse event. This indicates that the 250 mg initial dose was effective for 80% of the patients. Four patients with prehospital adverse events likely related to the administration of ketamine were found. One required suction, three (5%) requiring BVM respiratory support by EMS were subsequently intubated upon arrival in the ED. All 60 patients were discharged from the hospital alive. Further research is needed to determine an optimal single administration dose for ketamine in patients exhibiting signs of HDSA, if employing a standardized fixed dose medication protocol streamlines administration, and if the fixed dose medication reduces the occurrence of dosage errors.

Assessing experts' perspectives on challenges in substance misuse prevention, harm reduction, and treatment to shape funding priorities in New York State.

BACKGROUND: Drug overdose is a leading cause of death and opioid-related deaths increased by more than 300% from 2010 to 2020 in New York State. Experts holding a range of senior leadership positions from across New York State were asked to identify the greatest challenges in substance misuse prevention, harm reduction, and treatment continuum of care. Expert input was used to shape funding priorities. METHOD: Individual semi-structured interviews of sixteen experts were conducted in April and May 2023. Experts included academics, medical directors, leaders of substance misuse service agencies, administrators of a state agency, a county mental health commissioner, the president of a pharmacy chain, and a senior vice president of an addiction-related national non-profit. Zoom interviews were conducted individually by an experienced qualitative interviewer and were recorded, transcribed, and coded for content. An initial report, with the results of the interviews organized by thematic content, was reviewed by the research team and emailed to the expert interviewees for feedback. RESULTS: The research team identified five major themes: 1. Siloed and fragmented care delivery systems; 2. Need for a skilled workforce; 3. Attitudes towards addiction (stigma); 4. Limitations in treatment access; and 5. Social and drug related environmental factors. Most experts identified challenges in each major theme; over three-quarters identified issues related to siloed and fragmented systems and the need for a skilled workforce. Each expert mentioned more than one theme, three experts mentioned all five themes and six experts mentioned four themes. CONCLUSIONS: Research, educational, and programmatic agendas should focus on identified topics as a means of improving the lives of patients at risk for or suffering from substance use-related disorders. The results of this project informed funding of pilot interventions designed to address the identified care challenges.

Does Mixing Activated Charcoal With Cola Improve Tolerability Without Affecting Pharmacokinetics? A Randomized Controlled Crossover Trial.

INTRODUCTION: Activated charcoal is the most common form of gastrointestinal decontamination used for the poisoned patient. One limitation to its use is patient tolerability due to palatability. Some recommend mixing activated charcoal with cola to improve palatability. An important question is whether mixing activated charcoal with cola affects the ability of the activated charcoal to adsorb xenobiotic. METHODS: This was a prospective randomized controlled crossover trial. Five healthy adults aged 18 to 40 years were recruited. Participants received 45 mg/kg acetaminophen rounded down to the nearest whole tablet. One hour later, they were randomized to receive 50 g of an activated charcoal-water premixture alone or mixed with cola. Acetaminophen levels were collected. The area under the curve of acetaminophen concentrations over time was measured as a marker for degree of absorption. Participants also completed an appeal questionnaire in which they rated the activated charcoal preparations. Participants would then return after at least 7 days to repeat the study with the other activated charcoal preparation. RESULTS: Four male participants and 1 female participant were recruited. There was no statistical difference in preference score for activated charcoal alone versus the cola-activated charcoal mixture. There was no statistical difference in the area under the curve of acetaminophen concentrations over time between activated charcoal alone and the cola-activated charcoal mixture. Of note, the study is limited by the small sample size, limiting its statistical power. DISCUSSION: The absorption of acetaminophen in an overdose model is no different when participants received activated charcoal alone or a cola-activated charcoal mixture as suggested by area under the curve. In this small study, there was no difference in preference for activated charcoal alone or a cola-activated charcoal mixture across a range of palatability questions. On an individual level, some participants preferred the activated charcoal-cola mixture, and some preferred the activated charcoal alone.

A Qualitative Analysis of the Experiences of EMS Clinicians in Recognizing and Treating Witnessed Cardiac Arrests.

BACKGROUND: Survival from out of hospital cardiac arrest (OHCA) increases when effective cardiopulmonary resuscitation (CPR) and defibrillation are performed early. Patients who suffer OHCA in front of emergency medical services (EMS) clinicians have greater likelihood of survival, but little is known about how EMS clinicians think about and experience those events. We sought to understand how EMS clinicians assessed patients who devolved to cardiac arrest in their presence and uncover the perceived barriers and facilitators associated with recognizing and treating witnessed OHCAs. METHODS: EMS clinicians who had attended an EMS-witnessed OHCA and consented to participate were interviewed within 72 hours of the index case. Transcripts of the interviews were coded through the consolidated framework for implementation research to understand enabling and constraining factors involved and the predictability and anticipation of OHCA and subsequent management of patient care. Utstein data points, interventions, and associated times were extracted from the medical records. RESULTS: We interviewed 29 EMS clinicians who attended 27 EMS-witnessed OHCAs. Twenty-six (96.3%) of the EMS-witnessed OHCAs were preceded by prodromal symptoms and were classified as predictable. Of the predictable cases, clinicians anticipated 53.8% of them and attributed the prodromes of other cases to serious but not peri-arrest etiologies. Participants described various environmental, crew, and intrapersonal enabling and constraining factors associated with recognizing and treating EMS-witnessed OHCAs. Environmental elements included issues of safety and physical locations, crew elements included familiarity with their partners and working with them in the past, and intrapersonal elements included abilities to collect information and stress associated with responding to and managing the calls. CONCLUSION: Recognition and treatment of EMS-witnessed OHCAs are influenced by numerous environmental, crew, and intrapersonal factors. Future training and education on OHCA should include diverse locations, situations, and crew make-up, along with nontraditional patient complaints to broaden experiences associated with cardiac arrest management.

Transport Rates and Prehospital Intervals for an EMS Telemedicine Intervention.

INTRODUCTION: Emergency medical services (EMS) facilitated telemedicine encounters have been proposed as a strategy to reduce transports to hospitals for patients who access the 9-1-1 system. It is unclear which patient impressions are most likely able to be treated in place. It is also unknown if the increased time spent facilitating the telemedicine encounter is offset by the time saved from reducing the need for transport. The objective of this study was to determine the association between the impressions of EMS clinicians of the patients' primary problems and transport avoidance, and to describe the effects of telemedicine encounters on prehospital intervals. METHODS: This was a retrospective review of EMS records from two commercial EMS agencies in New York and Tennessee. For each EMS call where a telemedicine encounter occurred, a matched pair was identified. Clinicians' impressions were mapped to the corresponding category in the International Classification of Primary Care, 2nd edition (ICPC-2). Incidence and rates of transport avoidance for each category were determined. Prehospital interval was calculated as the difference between the time of ambulance dispatch and back-in-service time. RESULTS: Of the 463 prehospital telemedicine evaluations performed from March 2021 to April 2022, 312 (67%) avoided transports to the hospital. Respiratory calls were most likely to result in transport avoidance (p = 0.018); no other categories had statistically significant transport rates. Four hundred sixty-one (99.6%) had matched pairs identified and were included in the analysis. When compared to the matched pair, telemedicine without transport was associated with a prehospital interval reduction in 68% of the cases with a median reduction of 16 min; this is significantly higher than telemedicine with transport when compared to the matched pair with a median interval increase in 27 min. Regardless of transport status, the prehospital interval was a median of 4 min shorter for telemedicine encounters than non-telemedicine encounters (p = 0.08). CONCLUSION: In this study, most telemedicine evaluations resulted in ED transport avoidance, particularly for respiratory issues. Telemedicine interventions were associated with a median four-minute decrease in prehospital interval per call. Future research should investigate the long-term effects of telemedicine on patient outcomes.

Eating and Physical Activity Patterns in Day and Night Shift EMS Clinicians.

Objective: EMS clinicians work in shifts to provide 24-hour care. Shift work is linked with metabolic disease and over 70% of EMS clinicians report having overweight or obesity. Inability to store food in their vehicles combined with limited overnight dining establishments, and unpredictable job demands leads to reliance on convenience and fast foods. The objective of this study was to describe the eating and physical activity patterns among EMS clinicians on days on and off shift.Methods: EMS clinicians throughout the United States participated in a study involving four 24-hour monitoring periods. Participants wore activity monitors to measure physical activity level and remote food photography was used to collect dietary data on two work days and two days off. Repeated measures analysis of variance was conducted to compare energy and macronutrient intake and activity levels in day and night workers on and off shift.Results: We analyzed data from 39 EMS clinicians (29.7 + 8.5yrs old). Controlling for sex, those working night shifts consumed more kilocalories (p=.037) and total fat (p=.043) compared to day shift workers. Night shift workers had fewer steps (p = 0.045), more sedentary time (p = 0.053), and less moderate activity (p = 0.037) during a shift compared to day workers.Conclusion: Among EMS clinicians, night shift is associated with greater energy intake, and decreased physical activity during shifts. This may contribute to positive energy balance and weight gain overtime, increasing risk for metabolic disease.

The EMS Modified Early Warning Score (EMEWS): A Simple Count of Vital Signs as a Predictor of Out-of-Hospital Cardiac Arrests.

Objective: For patients at risk for out-of-hospital cardiac arrest (OHCA) after Emergency Medical Services (EMS) arrival, outcomes may be mitigated by identifying impending arrests and intervening before they occur. Tools such as the Modified Early Warning Score (MEWS) have been developed to determine the risk of arrest, but involve relatively complicated algorithms that can be impractical to compute in the prehospital environment. A simple count of abnormal vital signs, the "EMS Modified Early Warning Score" (EMEWS), may represent a more practical alternative. We sought to compare to the ability of MEWS and EMEWS to identify patients at risk for EMS-witnessed OHCA.Methods: We conducted a retrospect analysis of the 2018 ESO Data Collaborative database of EMS encounters. Patients without cardiac arrest before EMS arrival were categorized into those who did or did not have an EMS-witnessed arrest. MEWS was evaluated without its temperature component (MEWS-T). The performance of MEWS-T and EMEWS in predicting EMS witnessed arrest was evaluated by comparing receiver-operating characteristic curves.Results: Of 369,064 included encounters, 4,651 were EMS witnessed arrests. MEWS-T demonstrated an area under the curve (AUC) of 0.79 (95% CI: 0.79 - 0.80), with 86.8% sensitivity and 51.0% specificity for MEWS-T ≥ 3. EMEWS demonstrated an AUC of 0.74 (95% CI: 0.73 - 0.75), with 81.3% sensitivity and 53.9% specificity for EMEWS ≥ 2.Conclusions: EMEWS showed a similar ability to predict EMS-witnessed cardiac arrest compared to MEWS-T, despite being significantly simpler to compute. Further study is needed to evaluate whether the implementation of EMEWS can aid EMS clinicians in anticipating and preventing OHCA.

Ultrasonographic Inferior Vena Cava Measurement is More Sensitive Than Vital Sign Abnormalities for Identifying Moderate and Severe Hemorrhage.

BACKGROUND: Ultrasound inferior vena cava (IVC) diameter has been shown to decrease in response to hemorrhage. IVC diameter cut points to identify moderate and severe blood loss have not been established. OBJECTIVES: This study sought to find ultrasound IVC diameter cut points to identify moderate and severe hemorrhage and assess the performance of these cut points vs. vital sign abnormalities. METHODS: This is a secondary analysis of data from a study that described changes in vital signs and sonographic measurements of the IVC during a lower body negative pressure model of hemorrhage. Using receiver operator curve analyses, optimal cut points for identifying moderate and severe hemorrhage were identified. The ability of these cut points to identify hemorrhage in patients with no vital sign abnormalities was then assessed. RESULTS: In both long- and short-axis views, maximum and minimum IVC diameters (IVCmax and IVCmin) were significantly lower than baseline in severe blood loss. The optimal cut point for IVCmax in both axes was found to be ≤ 0.8 cm. This cut point is able to distinguish between no blood loss vs. moderate blood loss, and no blood loss vs. severe blood loss. The optimal cut point for IVCmin was variable between axes and blood loss severity. IVC diameter cut points obtained were able to identify hemorrhage in patients with no vital sign abnormalities. CONCLUSION: An ultrasound IVCmax of ≤ 0.8 cm may be useful in identifying moderate and severe hemorrhage before vital sign abnormalities are evident.

Physical symptoms provoked by normobaric hot and humid disabled pressurized rescue module scenarios.

We tested the hypothesis that thermal discomfort will be greater, mood will be worse, and physical symptoms of heat illness will be exacerbated with elevations in dry bulb temperature during exposure to >95% relative humidity disabled pressurized rescue module simulation. On three occasions, 15 healthy males (23 ± 3 years) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C or 35.0 ± 0.1°C, and 95 ± 2% relative humidity normobaric environments for eight hours. Thermal discomfort (visual analog scale), mood (profile of mood states), and physical symptoms of heat illness, ear-nose-throat, and muscle discomfort (environmental symptoms questionnaire) were assessed before and following each hour of exposure. Thermal discomfort was greater throughout the exposure in 35°C versus both 32°C and 33°C (p ≥ 0.03) and did not differ between the latter conditions (p ≥ 0.07). Mood worsened over time in all trials (p ≺ 0.01) and was worse in 35°C compared to 32°C and 33°C after five hours of exposure (p ≤ 0.05). Heat illness symptoms increased over time in all trials and was greater in 35°C versus 32°C and 33°C throughout the exposure (p ≤ 0.04). Ear-nose-throat and muscle discomfort symptoms increased over time in all trials (p < 0.01) and were higher in 35°C versus 32°C and 33°C after the sixth hour of exposure (p ≤ 0.02). In support of our hypothesis, mood was worse, physical symptoms of heat illness, and ear-nose-throat and muscle discomfort symptoms were exacerbated, and thermal discomfort was greater with elevations in dry bulb temperature during an eight-hour exposure to a >95% relative humidity disabled PRM simulation.

Thermoregulation during a six-hour exposure to warm, humid hyperbaric conditions.

Purpose: In a disabled submarine scenario, a pressurized rescue module (PRM) may be deployed to rescue survivors. If the PRM were to become disabled, conditions could become hot and humid exposing the occupants to heat stress. We tested the hypothesis that the rise in core temperature and fluid loss from sweating would increase with rising dry bulb temperature. Methods: Twelve males (age 22 ± 3 years; height 179 ± 7 cm; mass 77.4 ± 8.3 kg) completed this study. On three occasions, subjects were exposed to high humidity and either 28-, 32-, or 35˚C for six hours in a dry hyperbaric chamber pressurized to 6.1 msw. Changes in core temperature (Tc) and body mass were recorded and linear regression lines fit to estimate the predicted rise in Tc and loss of fluid from sweating. Results: Heart rate was higher in the 35°C condition compared to the 28°C and 32°C conditions. Tc was higher in the 32°C condition compared to 28°C and higher in 35°C compared to the 28˚°C and 32°C conditions. Projected fluid loss in all of the tested conditions could exceed 6% of body mass after 24 hours of exposure endangering the health of sailors in a DISSUB or disabled PRM. A fluid intake of 1.0 to 3.5 L would be required to limit dehydration to 2% or 4% of initial mass depending upon condition. Conclusions: Prolonged exposure to 35°C conditions under pressure results in uncompensable heat stress. 32°C and 35°C exposures were compensable under these conditions but further research is required to elucidate the effect of increased ambient pressure on thermoregulation.

Carotid body chemosensitivity is not attenuated during cold water diving.

Tonic carotid body (CB) activity is reduced during exposure to cold and hyperoxia. We tested the hypotheses that cold water diving lowers CB chemosensitivity and augments CO2 retention more than thermoneutral diving. Thirteen subjects [age: 26 ± 4 yr; body mass index (BMI): 26 ± 2 kg/m2) completed two 4-h head-out water immersion protocols in a hyperbaric chamber (1.6 ATA) in cold (15°C) and thermoneutral (25°C) water. CB chemosensitivity was assessed with brief hypercapnic ventilatory response ([Formula: see text]) and hypoxic ventilatory response ([Formula: see text]) tests before dive, 80 and 160 min into the dive (D80 and D160, respectively), and immediately after and 60 min after dive. Data are reported as an absolute mean (SD) change from predive. End-tidal CO2 pressure increased during both the thermoneutral water dive [D160: +2 (3) mmHg; P = 0.02] and the cold water dive [D160: +1 (2) mmHg; P = 0.03]. Ventilation increased during the cold water dive [D80: 4.13 (4.38) and D160: 7.75 (5.23) L·min-1; both P < 0.01] and was greater than the thermoneutral water dive at both time points (both P < 0.01). [Formula: see text] was unchanged during the dive (P = 0.24) and was not different between conditions (P = 0.23). [Formula: see text] decreased during the thermoneutral water dive [D80: -3.45 (3.61) and D160: -2.76 (4.04) L·min·mmHg-1; P < 0.01 and P = 0.03, respectively] but not the cold water dive. However, [Formula: see text] was not different between conditions (P = 0.17). In conclusion, CB chemosensitivity was not attenuated during the cold stress diving condition and does not appear to contribute to changes in ventilation or CO2 retention.

Inferior Vena Cava Diameter is an Early Marker of Central Hypovolemia during Simulated Blood Loss.

INTRODUCTION: Inferior vena cava (IVC) diameter decreases under conditions of hypovolemia. Point-of-care ultrasound (POCUS) may be useful to emergently assess IVC diameter. This study tested the hypothesis that ultrasound measurements of IVC diameter decreases during severe simulated blood loss. METHODS: Blood loss was simulated in 14 healthy men (22 ± 2 years) using lower body negative pressure (LBNP). Pressure within the LBNP chamber was reduced 10 mmHg of LBNP every four minutes until participants experienced pre-syncopal symptoms or until 80 mmHg of LBNP was completed. IVC diameter was imaged with POCUS using B-mode in the long and short axis views between minutes two and four of each stage. RESULTS: Maximum IVC diameter in the long axis view was lower than baseline (1.5 ± 0.4 cm) starting at -20 mmHg of LBNP (1.0 ± 0.3 cm; p < 0.01) and throughout LBNP (p < 0.01). The minimum IVC diameter in the long axis view was lower than baseline (0.9 ± 0.3 cm) at -20 mmHg of LBNP (0.5 ± 0.3 cm; p < 0.01) and throughout LBNP (p < 0.01). Maximum IVC diameter in the short axis view was lower than baseline (0.9 ± 0.2 cm) at 40 mmHg of LBNP (0.6 ± 0.2; p = 0.01) and the final LBNP stage (0.6 ± 0.2 cm; p < 0.01). IVC minimum diameter in the short axis view was lower than baseline (0.5 ± 0.2 cm) at the final LBNP stage (0.3 ± 0.2 cm; p = 0.01). CONCLUSION: These data demonstrate that IVC diameter decreases prior to changes in traditional vital signs during simulated blood loss. Further study is needed to determine the view and diameter threshold that most accurate for identifying hemorrhage requiring emergent intervention.

The Association of Death Notification and Related Training with Burnout among Emergency Medical Services Professionals.

INTRODUCTION: Death notification is a difficult task commonly encountered during prehospital care and may lead to burnout among EMS professionals. Lack of training could potentiate the relationship between death notification and burnout. The first objective of this study was to describe EMS professionals' experience with death notification and related training. The secondary objective was to assess the associations between death notification delivery, training, and burnout. Methods: We administered an electronic questionnaire to a random sample of nationally-certified EMS professionals. Work-related burnout was measured using the validated Copenhagen Burnout Inventory. Analysis was stratified by certification level to basic life support (BLS) and advanced life support (ALS). The association between the number of adult (≥18 years) patient death notifications delivered in the prior 12 months and burnout was assessed using multivariable logistic regression to adjust for confounding variables. Multivariable logistic regression modeling was used to assess the adjusted association between training and burnout among those who reported delivering at least one death notification in the prior 12 months. Adjusted odds ratios (aOR) and 95% confidence intervals are reported (95% CI). Results: We received 2,333/19,330 (12%) responses and 1,514 were included in the analysis. Most ALS respondents (77%) and one-third of BLS respondents (33%) reported at least one adult death notification in the past year. Approximately half of respondents reported receiving death notification training as part of their initial EMS education program (51% BLS; 52% ALS) and fewer reported receiving continuing education (30% BLS; 44% ALS). Delivering a greater number of death notifications was associated with increased odds of burnout. Among those who delivered at least one death notification, continuing education was associated with reduced odds of burnout. Conclusion: Many EMS professionals reported delivering at least one death notification within the past year. Yet, fewer than half reported training related to death notification during initial EMS education and even fewer reported receiving continuing education. More of those who delivered death notifications experienced burnout, while continuing education was associated with reduced odds of burnout. Future work is needed to develop and evaluate death notification training specifically for EMS professionals.

Changes in Field Termination of Resuscitation and Survival Rates After an Educational Intervention to Promote on Scene Resuscitation for Out-of-Hospital Cardiac Arrest.

BACKGROUND: Emergency medical services (EMS) agencies with higher field termination-of-resuscitation (TOR) rates tend to have higher survival rates from out-of-hospital cardiac arrest (OHCA). Whether EMS agencies can improve survival rates through efforts to focus on resuscitation on scene and optimize TOR rates is unknown. OBJECTIVE: The goal of this study was to determine if an EMS agency's efforts to enhance on-scene resuscitation were associated with increased TOR and OHCA survival with favorable neurologic outcome. METHODS: A single-city, retrospective analysis of prospectively collected 2017 quality assurance data was conducted. Patient demographics, process, and outcome measures were compared before and after an educational intervention to increase field TOR. The primary outcome measure was survival to hospital discharge with favorable neurologic status. RESULTS: There were 320 cases that met inclusion criteria. No differences in age, gender, location, witnessed arrest, bystander cardiopulmonary resuscitation, initial shockable rhythm, or presumed cardiac etiology were found. After the intervention, overall TOR rate increased from 39.6% to 51.1% (p = 0.06). Among subjects transported without return of spontaneous circulation (ROSC), average time on scene increased from 26.4 to 34.2 min (p = 0.02). Rates of sustained ROSC and survival to hospital admission were similar between periods. After intervention, there was a trend toward increased survival to hospital discharge rate (relative risk [RR] 2.09; 95% confidence interval [CI] 0.74-5.91) and an increase in survival with favorable neurologic status rate (RR 5.96; 95% CI 0.80-44.47). CONCLUSION: This study described the association between an educational intervention focusing on optimization of resuscitation on scene and OHCA process and outcome measures. Field termination has the potential to serve as a surrogate marker for aggressively treating OHCA patients on scene.

Variability in venous gas emboli following the same dive at 3,658 meters.

Exposure to a reduction in ambient pressure such as in high-altitude climbing, flying in aircrafts, and decompression from underwater diving results in circulating vascular gas bubbles (i.e., venous gas emboli [VGE]). Incidence and severity of VGE, in part, can objectively quantify decompression stress and risk of decompression sickness (DCS) which is typically mitigated by adherence to decompression schedules. However, dives conducted at altitude challenge recommendations for decompression schedules which are limited to exposures of 10,000 feet in the U.S. Navy Diving Manual (Rev. 7). Therefore, in an ancillary analysis within a larger study, we assessed the evolution of VGE for two hours post-dive using echocardiography following simulated altitude dives at 12,000 feet. Ten divers completed two dives to 66 fsw (equivalent to 110 fsw at sea level by the Cross correction method) for 30 minutes in a hyperbaric chamber. All dives were completed following a 60-minute exposure at 12,000 feet. Following the dive, the chamber was decompressed back to altitude for two hours. Echocardiograph measurements were performed every 20 minutes post-dive. Bubbles were counted and graded using the Germonpré and Eftedal and Brubakk method, respectively. No diver presented with symptoms of DCS following the dive or two hours post-dive at altitude. Despite inter- and intra-diver variability of VGE grade following the dives, the majority (11/20 dives) presented a peak VGE Grade 0, three VGE Grade 1, one VGE Grade 2, four VGE Grade 3, and one VGE Grade 4. Using the Cross correction method for a 66-fsw dive at 12,000 feet of altitude resulted in a relatively low decompression stress and no cases of DCS.

Variability in venous gas emboli following the same dive at 3,658 meters.

Exposure to a reduction in ambient pressure such as in high-altitude climbing, flying in aircrafts, and decompression from underwater diving results in circulating vascular gas bubbles (i.e., venous gas emboli [VGE]). Incidence and severity of VGE, in part, can objectively quantify decompression stress and risk of decompression sickness (DCS) which is typically mitigated by adherence to decompression schedules. However, dives conducted at altitude challenge recommendations for decompression schedules which are limited to exposures of 10,000 feet in the U.S. Navy Diving Manual (Rev. 7). Therefore, in an ancillary analysis within a larger study, we assessed the evolution of VGE for two hours post-dive using echocardiography following simulated altitude dives at 12,000 feet. Ten divers completed two dives to 66 fsw (equivalent to 110 fsw at sea level by the Cross correction method) for 30 minutes in a hyperbaric chamber. All dives were completed following a 60-minute exposure at 12,000 feet. Following the dive, the chamber was decompressed back to altitude for two hours. Echocardiograph measurements were performed every 20 minutes post-dive. Bubbles were counted and graded using the Germonpré and Eftedal and Brubakk method, respectively. No diver presented with symptoms of DCS following the dive or two hours post-dive at altitude. Despite inter- and intra-diver variability of VGE grade following the dives, the majority (11/20 dives) presented a peak VGE Grade 0, three VGE Grade 1, one VGE Grade 2, four VGE Grade 3, and one VGE Grade 4. Using the Cross correction method for a 66-fsw dive at 12,000 feet of altitude resulted in a relatively low decompression stress and no cases of DCS.

Respiratory muscle training and exercise ventilation while diving at altitude.

Introduction: Pre-dive altitude exposure may increase respiratory fatigue and subsequently augment exercise ventilation at depth. This study examined pre-dive altitude exposure and the efficacy of resistance respiratory muscle training (RMT) on respiratory fatigue while diving at altitude. Methods: Ten men (26±5 years; VO2peak: 39.8±3.3 mL• kg-1•min-1) performed three dives; one control (ground level) and two simulated altitude dives (3,658 m) to 17 msw, relative to ground level, before and after four weeks of resistance RMT. Subjects performed pulmonary function testing (e.g., inspiratory [PI] and expiratory [PE] pressure testing) pre- and post-RMT and during dive visits. During each dive, subjects exercised for 18 minutes at 55% VO2peak, and ventilation (VE), breathing frequency (ƒb,), tidal volume (VT) and rating of perceived exertion (RPE) were measured. Results: Pre-dive altitude exposure reduced PI before diving (p=0.03), but had no effect on exercise VE, ƒb, or VT at depth. At the end of the dive in the pre-RMT condition, RPE was lower (p=0.01) compared to control. RMT increased PI and PE (p<0.01). PE was reduced from baseline after diving at altitude (p<0.03) and this was abated after RMT. RMT did not improve VE or VT at depth, but decreased ƒb (p=0.01) and RPE (p=0.048) during the final minutes of exercise. Conclusion: Acute altitude exposure pre- and post-dive induces decrements in PI and PE before and after diving, but does not seem to influence ventilation at depth. RMT reduced ƒb and RPE during exercise at depth, and may be useful to reduce work of breathing and respiratory fatigue during dives at altitude.

Human thermoregulation during prolonged exposure to warm and extremely humid environments expected to occur in disabled submarine scenarios.

Military and civilian emergency situations often involve prolonged exposures to warm and very humid environments. We tested the hypothesis that increases in core temperature and body fluid losses during prolonged exposure to warm and very humid environments are dependent on dry bulb temperature. On three occasions, 15 healthy males (23 ± 3 yr) sat in 32.1 ± 0.1°C, 33.1 ± 0.2°C, or 35.0 ± 0.1°C and 95 ± 2% relative humidity normobaric environments for 8 h. Core temperature (telemetry pill) and percent change in body weight, an index of changes in total body water occurring secondary to sweat loss, were measured every hour. Linear regression models were fit to core temperature (over the final 4 h) and percent changes in body weight (over the entire 8 h) for each subject. These equations were used to predict core temperature and percent changes in body weight for up to 24 h. At the end of the 8-h exposure, core temperature was higher in 35°C (38.2 ± 0.4°C, P < 0.01) compared with 32°C (37.2 ± 0.2°C) and 33°C (37.5 ± 0.2°C). At this time, percent changes in body weight were greater in 35°C (-1.9 ± 0.5%) compared with 32°C (-1.4 ± 0.3%, P < 0.01) but not 33°C (-1.6 ± 0.6%, P = 0.17). At 24 h, predicted core temperature was higher in 35°C (39.2 ± 1.4°C, P < 0.01) compared with 32°C (37.6 ± 0.9°C) and 33°C (37.5 ± 0.9°C), and predicted percent changes in body weight were greater in 35°C (-6.1 ± 2.4%) compared with 32°C (-4.6 ± 1.5%, P = 0.04) but not 33°C (-5.3 ± 2.0%, P = 0.43). Prolonged exposure to 35°C, but not 32°C or 33°C, dry bulb temperatures and high humidity is uncompensable heat stress, which exacerbates body fluid losses.

Non-Auto-Injector Epinephrine Administration by Basic Life Support Providers: A Literature Review and Consensus Process.

Anaphylaxis is a life-threatening condition with a known effective prehospital intervention: parenteral epinephrine. The National Association of EMS Physicians (NAEMSP) advocates for emergency medical services (EMS) providers to be allowed to carry and administer epinephrine. Some states constrain epinephrine administration by basic life support (BLS) providers to administration using epinephrine auto-injectors (EAIs), but the cost and supply of EAIs limits the ability of some EMS agencies to provide epinephrine for anaphylaxis. This literature review and consensus report describes the extant literature and the practical and policy issues related to non-EAI administration of epinephrine for anaphylaxis, and serves as a supplementary resource document for the revised NAEMSP position statement on the use of epinephrine in the out-of-hospital treatment of anaphylaxis, complementing (but not replacing) prior resource documents. The report concludes that there is some evidence that intramuscular injection of epinephrine drawn up from a vial or ampule by appropriately trained EMS providers-without limitation to specific certification levels-is safe, facilitates timely treatment of patients, and reduces costs.