Prehospital Surgical Airway Management: An NAEMSP Position Statement and Resource Document

Bag-valve-mask ventilation and endotracheal intubation have been the mainstay of prehospital airway management for over four decades. Recently, supraglottic device use has risen due to various factors. The combination of bag-valve-mask ventilation, endotracheal intubation, and supraglottic devices allows for successful airway management in a majority of patients. However, there exists a small portion of patients who are unable to be intubated and cannot be adequately ventilated with either a facemask or a supraglottic airway. These patients require an emergent surgical airway. A surgical airway is an important component of all airway algorithms, and in some cases may be the only viable approach; therefore, it is imperative that EMS agencies that are credentialed to manage airways have the capability to perform surgical airways when appropriate. The National Association of Emergency Medical Services Physicians (NAEMSP) recommends the following for emergency medical services (EMS) agencies that provide advanced airway management.A surgical airway is reasonable in the prehospital setting when the airway cannot be secured by less invasive means.When indicated, a surgical airway should be performed without delay.A surgical airway is not a substitute for other airway management tools and techniques. It should not be the only rescue option available.Success of an open surgical approach using a scalpel is higher than that of percutaneous Seldinger techniques or needle-jet ventilation in the emergency setting.

Pain is common after sexual assault and posttraumatic arousal/reactivity symptoms mediate the development of new or worsening persistent pain

ABSTRACT

Clinically significant new or worsening pain (CSNWP) is a common, yet often overlooked, sequelae of sexual assault. Little is known regarding factors influencing the development of CSNWP in sexual assault survivors. The current study used data from a recently completed prospective study to evaluate whether posttraumatic alterations in arousal and reactivity in the early aftermath of sexual assault influence the transition from acute to clinically significant new or worsening persistent pain. Women ≥ 18 years of age (n = 706) presenting for emergency care after sexual assault to 13 emergency care sites were enrolled in the study. Women completed assessments at the time of presentation as well as at 1 week (n = 706, 100%) and 6 weeks (n = 630, 91%). Nearly 70% of women reported CSNWP at the time of emergency care (n = 475, 69%), which persisted to 6 weeks in approximately 2 in 5 survivors (n = 248, 41%). A structural equation model adjusted for age, race, past trauma exposure, and preassault pain levels suggested that posttraumatic alterations in arousal/reactivity symptoms 1 week after assault partially mediated the transition from acute to persistent CSNWP. A significant portion (41%) of women sexual assault survivors develop CSNWP 6 weeks postassault. Posttraumatic arousal/reactivity symptoms in the early aftermath of assault contribute to CSNWP development; such symptoms are potential targets for secondary preventive interventions to reduce chronic postassault pain.

Perceived Care Quality Among Women Receiving Sexual Assault Nurse Examiner Care: Results From a 1-Week Postexamination Survey in a Large Multisite Prospective Study

INTRODUCTION

This study examined the perspectives of female patients who had been sexually assaulted regarding the quality of care provided by sexual assault nurse examiners, including whether the patients' perspectives varied by their demographic characteristics and health status before the assault.

METHODS

A total of 695 female patients who received care from sexual assault nurse examiners at 13 United States emergency care centers and community-based programs completed standardized surveys 1 week after receiving sexual assault nurse examiners' care for sexual assault.

RESULTS

Most patients strongly agreed that the sexual assault nurse examiners provided high-quality care, including taking patients' needs/concerns seriously, not acting as though the assault was the patient's fault, showing care/compassion, explaining the sexual assault examination, and providing follow-up information. The perceptions did not vary by the patients' demographic characteristics or preassault health status.

DISCUSSION

Female patients who had been sexually assaulted and who were evaluated at 13 widely geographically distributed sexual assault nurse examiners' programs consistently reported that the sexual assault nurse examiners provided high-quality, compassionate care.

A comparison of three conducted electrical weapons in a surrogate swine cardiac safety model

We used a previously described methodology in a swine model to compare the relative cardiac safety of the Axon T7 Conducted Electrical Weapon (CEW), released in October of 2018, to two prior generations of Axon CEWs to include the X2 and the X26E. A total of 5 swine (252 total CEW exposures) were tested by alternating the three weapons at each chest exposure location. Our testing, using systemic hypotension as the quantitative surrogate for cardiac capture, demonstrated that the T7 and X2 were not statistically different. Both were superior, in terms of reduced hypotension during exposure, to the X26E. This study is important as it demonstrates that the newly released weapon is non-inferior to the X2 and superior to the X26E using this surrogate safety model. It is also important because it is the first study to examine the cardiac effects of simultaneous multi-bay exposures. Our prior study compared the X2 to the X26E but examined only single bay exposures from the X2. Lastly, we feel we have improved the methodology for studying the comparative cardiac effects of CEWs.

Neither Basic Life Support knowledge nor self-efficacy are predictive of skills among dental students

AIM

Basic life support (BLS) is considered a core competence for the graduating dentist. This study aimed to measure BLS knowledge, self-efficacy and skills of undergraduate dental students in Dublin.

METHODS

This study consisted of a cross-sectional survey measuring BLS knowledge and self-efficacy, accompanied by a directly observed BLS skills assessment in a subsample of respondents. Data were collected in January 2014. Bivariate correlations between descriptive and outcome variables (knowledge, self-efficacy and skills) were tested using Pearson's chi-square. We included knowledge and self-efficacy as predictor variables, along with other variables showing association, into a binary logistic regression model with BLS skills as the outcome measure.

RESULTS

One hundred and thirty-five students participated. Almost all (n = 133, 98.5%) participants had BLS training within the last 2 years. One hundred and four (77%) felt that they were capable of providing effective BLS (self-efficacy), whilst only 46 (34.1%) scored >80% of knowledge items correct. Amongst the skills (n = 85) subsample, 38.8% (n = 33) were found to pass the BLS skills assessment. Controlling for gender, age and skills assessor, the regression model did not identify a predictive relationship between knowledge or self-efficacy and BLS skills.

CONCLUSIONS

Neither knowledge nor self-efficacy was predictive of BLS skills. Dental students had low levels of knowledge and skills in BLS. Despite this, their confidence in their ability to perform BLS was high and did not predict actual competence. There is a need for additional hands-on training, focusing on self-efficacy and BLS skills, particularly the use of AED.

Breast nodularity and ulceration: diffuse dermal angiomatosis a corticosteroid responsive disease

Diffuse dermal angiomatosis of the breast (DDAB) is an uncommon ulcerative angiomatosis, which occurs in middle aged women with large pendulous breasts, a history of cigarette smoking, and risk factors for atherosclerosis. Based on its rarity, no well-defined therapeutic regimen has been elucidated. We report a case of DDAB in a woman with no history of smoking or radiographic evidence of occluded vasculature who presented with ulceration and pain-associated breast nodularity. She had a complete reproducible response to oral corticosteroids.

Dementia is associated with open-angle glaucoma: a population-based study

PURPOSE

Previous epidemiologic studies that focused on the association between open-angle glaucoma (OAG) and dementia showed inconsistent results. In the present study, we explored the association between OAG and dementia in an ethnic Chinese (i.e., Taiwanese) population using a population-based data set.

METHODS

We retrieved data on study subjects for this case-control study from the Longitudinal Health Insurance Database 2000. We identified 7770 patients who had a diagnosis of dementia as cases, and 7770 subjects matched in terms of sex and age, which were randomly extracted as controls. A conditional logistic regression conditioned on age group, sex, and index year was used to assess the association of dementia with previously diagnosed OAG among the sampled patients.

RESULTS

Of 15,540 patients, 1.70% had prior OAG, including 2.02% of the dementia group and 1.38% of the controls. After adjusting for patient socioeconomic characteristics and comorbid medical disorders, dementia patients were more likely to have had prior OAG than controls (odds ratio (OR): 1.44; 95% confidence interval (CI): 1.12-1.85; P<0.01). In addition, female dementia patients were more likely to have had prior OAG than controls (OR: 1.93; 95% CI: 1.35-2.77; P<0.001), whereas no statistical difference in prior OAG between male dementia patients and controls was found.

CONCLUSIONS

Female dementia patients were associated with a higher proportion of prior OAG than were the controls.

Conducted electrical weapons within healthcare: a comprehensive use of force model

Healthcare settings are experiencing increased amounts of violent activity that are challenging to the health care security profession. There is difficulty in addressing this issue completely. Some of this difficulty is because of factors that include inexperienced and untrained clinicians and administrators that are often the decision-makers in the health care setting. As part of an effective solution, we propose that a security plan, including a comprehensive use of force program incorporating conducted electrical weapons, is a necessary and best-practice goal. This paper outlines the background of the problem and discusses the challenges we encountered in reaching this goal as well as the benefits we have discovered along the way. This paper will be beneficial to any healthcare security professional that is interested in enhancing or improving their current health care security use of force model to further counter the increasing violent activity in their respective healthcare setting.

Physiologic effects of a new-generation conducted electrical weapon on human volunteers

BACKGROUND

Conducted electrical weapons (CEWs) are used by law enforcement to restrain or repel potentially violent persons. The TASER X2 CEW is a next-generation device with new technology, including new electrical waveform and output specifications. It has not previously been studied in humans.

OBJECTIVE

The objective of this study was to evaluate the human physiologic effect of a new-generation CEW.

METHODS

This was a prospective, observational human study. Volunteers received a 10-s exposure via deployed probes from an X2 CEW in the abdomen and upper thigh. Measured data included vital signs; 12-lead electrocardiograms; and blood serum biomarkers before, immediately after, and 24 h post exposure. Biomarkers measured included pH, lactate, potassium, creatine kinase (CK), and troponin-I. Real-time spirometry and echocardiography were performed before, during, and after the exposure.

RESULTS

Ten volunteers completed the study. There were no important changes in vital signs or potassium. Median increase in lactate as a consequence of the exposure was 1.2 mg/dL (range 0.6-2.8 mg/dL). Median change in pH was -0.031 (range -0.011 to -0.067). No subject had a positive troponin. Median change in CK at 24 h was 313 ng/mL (range -40 to 3418 ng/mL). There was no evidence of respiratory impairment. Baseline median minute ventilation was 14.2 L/min, increased to 21.6 L/min intra-exposure (p = 0.05), and remained elevated at 21.6 L/min post exposure (p = 0.01).

CONCLUSIONS

There was no evidence of dangerous physiology found in the measured parameters. The physiologic effects of the X2 CEW are similar to older-generation CEWs. We encourage further study to validate these results.

Randomized clinical trial of the effect of supplemental opioids in procedural sedation with propofol on serum catecholamines

OBJECTIVES

The objective was to assess the effect on stress biomarkers of supplemental opioid to a standard propofol dosing protocol for emergency department (ED) procedural sedation (PS). The hypothesis was that there is no difference in the change in serum catecholamines between PS using propofol with or without supplemental alfentanil.

METHODS

This was a randomized, nonblinded pilot study of adult patients undergoing PS in the ED for the reduction of fractures and dislocations. Patients with pain before the procedure were treated with intravenous (IV) morphine sulfate until their pain was adequately treated for at least 20 minutes before starting the procedure. Patients were randomized to receive either 10 μg/kg alfentanil followed by 1 mg/kg propofol, followed by 0.5 mg/kg every 3 minutes as needed, or propofol only, dosed in similar fashion without supplemental alfentanil. Doses, vital signs, nasal end-tidal CO2 (ETCO2), pulse oximetry, and bispectral electroencephalogram (EEG) analysis scores were recorded. Subclinical respiratory depression was defined as a change in ETCO2 > 10 mm Hg, an oxygen saturation of < 92% at any time, or an absent ETCO2 waveform at any time. Clinical events related to respiratory depression were noted during the procedure, including the addition of or increase in the flow rate of supplemental oxygen, the use of a bag-valve-mask apparatus, airway repositioning, or stimulation to induce breathing. Blood was drawn 1 minute prior to the administration of the medications for PS and again 1 minute after completion of the procedure for which the patient was sedated. Serum was tested for total catecholamines, epinephrine, norepinephrine, and dopamine. Postprocedure, patients were asked to report any pain perceived during the procedure. Data were analyzed using descriptive statistics, Wilcoxon rank sum tests, and chi-square tests, as appropriate.

RESULTS

Twenty patients were enrolled; 10 received propofol and 10 received propofol with alfentanil. No clinically significant complications were noted. Subclinical respiratory depression was seen in four of 10 (40%) patients in the propofol group and five of 10 (50%) patients in the propofol/alfentanil group (effect size = -10%, 95% confidence interval [CI] = -53% to 33%). There was no difference in the rate of clinical signs of respiratory depression between the two groups. Pain during the procedure was reported by two of 10 (20%) patients in the propofol group and five of 10 (50%) patients in the propofol/alfentanil group (effect size = -30%, 95% CI = -70% to 10%). Recall of some part of the procedure was reported by 0 of 10 (0%) patients in the propofol group and five of 10 (50%) of patients in the propofol/alfentanil group (effect size = -50%, 95% CI = -81% to -19%). There was no difference in the baseline or postprocedure catecholamine levels between the groups.

CONCLUSIONS

No difference in serum catecholamines was detected immediately after PS between patients who receive propofol with and without supplemental opioid in this small pilot study. PS using propofol only without supplemental opioid did not appear to induce markers of physiologic stress in this small pilot study.

Acidosis and catecholamine evaluation following simulated law enforcement "use of force" encounters

OBJECTIVES

Law enforcement authorities are often charged with controlling resisting suspects. These encounters sometimes result in the sudden and unexpected death of the suspect. Drug intoxication, excited delirium syndrome, or excessive uses of force are factors that are often blamed, but sometimes the mechanism of these deaths is not fully understood. It is possible that worsening acidosis or excessive catecholamine release play a part. The objective of this study was to determine the effect on markers of acidosis and catecholamines of various tasks intended to simulate common arrest-related situations.

METHODS

Subjects were assigned to one of five task groups: 1) a 150-meter sprint and wall hurdle (simulated flight from arrest); 2) 45 seconds of striking a heavy bag (simulated physical resistance); 3) a 10-second TASER X26 electronic control device exposure; 4) a fleeing and resistance exercise involving a law enforcement dog (K-9); or 5) an oleoresin capsicum (OC) exposure to the face and neck. Baseline serum pH, lactate, potassium, troponin I, catecholamines, and creatine kinase (CK) were evaluated. Serum catecholamines, pH, lactate, and potassium were sampled immediately after the task and every 2 minutes for 10 minutes posttask. Vital signs were repeated immediately after the task. Serum CK and troponin I were evaluated again at 24 hours posttask.

RESULTS

Sixty-six subjects were enrolled; four did not complete their assigned task. One subject lost the intravenous (IV) access after completing the task and did not have data collected, and one subject only received a 5-second TASER device exposure and was excluded from the study, leaving 12 subjects in each task group. The greatest changes in acidosis markers occurred in the sprint and heavy bag groups. Catecholamines increased the most in the heavy bag group and the sprint group and increased to a lesser degree in the TASER, OC, and K-9 groups. Only the sprint group showed an increase in CK at 24 hours. There were no elevations in troponin I in any group, nor any clinically important changes in potassium.

CONCLUSIONS

The simulations of physical resistance and fleeing on foot led to the greatest changes in markers of acidosis and catecholamines. These changes may be contributing or causal mechanisms in sudden custodial arrest-related deaths (ARDs). This initial work may have implications in guiding applications of force for law enforcement authorities (LEAs) when apprehending resisting subjects.

Effect of an electronic control device exposure on a methamphetamine-intoxicated animal model

OBJECTIVES

Because of the prevalence of methamphetamine abuse worldwide, it is not uncommon for subjects in law enforcement encounters to be methamphetamine-intoxicated. Methamphetamine has been present in arrest-related death cases in which an electronic control device (ECD) was used. The primary purpose of this study was to determine the cardiac effects of an ECD in a methamphetamine intoxication model.

METHODS

Sixteen anesthetized Dorset sheep (26-78 kg) received 0.0 mg/kg (control animals, n = 4), 0.5 mg/kg (n = 4), 1.0 mg/kg (n = 4), or 1.5 mg/kg (n = 4) of methamphetamine hydrochloride as a slow intravenous (IV) bolus during continuous cardiac monitoring. The animals received the following exposures in sequence from a TASER X26 ECD beginning at 30 minutes after the administration of the drug: 1) 5-second continuous exposure, 2) 15-second intermittent exposure, 3) 30-second intermittent exposure, and 4) 40-second intermittent exposure. Darts were inserted at the sternal notch and the cardiac apex, to a depth of 9 mm. Cardiac motion was determined by thoracotomy (smaller animals, < or = 32 kg) or echocardiography (larger animals, > 68 kg). Data were analyzed using descriptive statistics and chi-square tests.

RESULTS

Animals given methamphetamine demonstrated signs of methamphetamine toxicity with tachycardia, hypertension, and atrial and ventricular ectopy in the 30-minute period immediately after administration of the drug. Smaller animals (n = 8, < or = 32 kg, mean = 29.4 kg) had supraventricular dysrhythmias immediately after the ECD exposures. Larger animals (n = 8, > 68 kg, mean = 72.4) had only sinus tachycardia after the exposures. One of the smaller animals had frequent episodes of ventricular ectopy after two exposures, including runs of delayed onset, nonsustained six- to eight-beat unifocal and multifocal ventricular tachycardia that spontaneously resolved. This animal had significant ectopy prior to the exposures as well. Thoracotomy performed on three smaller animals demonstrated cardiac capture during ECD exposure consistent with previous animal studies. In the larger animals, none of the methamphetamine-intoxicated animals demonstrated cardiac capture. Two control sheep showed evidence of capture similar to the smaller animals. No ventricular fibrillation occurred after the exposure in any animal.

CONCLUSIONS

In smaller animals (32 kg or less), ECD exposure exacerbated atrial and ventricular irritability induced by methamphetamine intoxication, but this effect was not seen in larger, adult-sized animals. There were no episodes of ventricular fibrillation after exposure associated with ECD exposure in methamphetamine-intoxicated sheep.

The physiologic effects of multiple simultaneous electronic control device discharges

OBJECTIVES

Law enforcement and military personnel use electronic control devices to control non-compliant and actively resistive subjects. The TASER((R)) Shockwave is a new electronic control device designed specifically as an area denial device capable of delivering multiple simultaneous discharges. This is the first study to examine the effects of multiple simultaneous device discharges in humans.

METHODS

Volunteers were exposed to multiple (two to three), simultaneous 5-second discharges from the Shockwave device to the chest, back, chest to abdomen, or thighs. Blood was analyzed before and after discharge for pH, lactate, potassium, creatine kinase (CK), and troponin. Continuous spirometry was performed before, during, and after the discharge. In addition, electrocardiograms (ECGs) before and after discharge were recorded, and echocardiography was used to determine the rhythm during discharge.

RESULTS

Small elevations of lactate occurred. Moderate increases in CK at 24 hours occurred and appeared to be related to the number of simultaneous discharges. There was a trend to a decrease in minute ventilation in the volunteers exposed to two simultaneous discharges, but it did not reach statistical significance. ECG changes only reflected an increase in vagal tone, and there was no evidence of capture by echocardiography. Five-second, simultaneous, multiple exposures to the TASER Shockwave device were reasonably tolerated by our human volunteers.

CONCLUSION

Our study suggests that this device may have a reasonable risk/benefit ratio when used to protect an area from a threat.

Prolonged TASER use on exhausted humans does not worsen markers of acidosis

OBJECTIVE

There are safety concerns about TASER conducted electrical weapon (CEW) use on humans, and there have been media reports of adverse human outcomes after CEW exposure. Conducted electrical weapons are often used on physically exhausted subjects. A single CEW application of a CEW is generally accepted to be 5 seconds of exposure. Some exposures in reality involve more than 5 seconds. We sought to determine if a prolonged (15 seconds) CEW exposure on exhausted humans caused acidosis, hyperkalemia, serum lactate change, or troponin change.

METHODS

This was a prospective study of generally healthy human volunteers. Medical histories and baseline serum values were obtained, and several of the volunteers did have acute or chronic medical problems. Subjects underwent an exercise protocol until subjective exhaustion. Exhaustion was defined by the volunteer no longer being able to perform the exercise at a given pace. Blood was drawn immediately (defined as within 20 seconds) after exercise and was immediately followed by a 15-second CEW exposure. Blood was drawn immediately after exposure and again at 16 to 24 hours after exposure. Blood was analyzed for pH, pco(2), potassium, lactate, and troponin. Data were compared using Wilcoxon signed rank tests.

RESULTS

There were 38 subjects enrolled with an average age of 39 years. The following health conditions were reported among the volunteers: hypertension (2), gastritis/reflux (2), active respiratory tract infections (3), asthma (2), chronic muscular pain conditions (4), pituitary adenoma (1) and glaucoma (1). Sixteen volunteers reported use of prescription medication at the time of their participation. The median initial pH of 7.38 (interquartile range [IQR], 7.35-7.40) decreased to 7.23 (IQR, 7.19-7.31) immediately after exercise. Immediately after exposure, median pH was 7.22 (IQR, 7.18-7.25). It was 7.39 (IQR, 7.37-7.43) at 24 hours. The pCO2 increased from 46.3 (IQR, 43.0-54.5) to 57.4 (IQR, 49.9-67.7) immediately after exercise, decreased to 51.3 (IQR, 44.4-65.0) immediately after exposure, and was 46.3 (IQR, 42.7-51.7) at 24 hours. Lactate increased from a median of 1.65 (IQR, 1.14-2.55) to 8.39 (IQR, 6.98-11.66) immediately after exercise, increased to 9.85 (IQR, 7.70-12.87) immediately after exposure, and was 1.02 (IQR, 0.91-1.57) at 24 hours. Serum potassium increased from 3.9 (IQR, 3.8-4.4) to 4.2 (IQR, 4.0-4.9) immediately after exercise, decreased to 3.8 (IQR, 3.7-4.4) immediately after exposure, and was 4.1 (IQR, 3.9-4.6) at 24 hours. No troponin elevations were detected.

CONCLUSION

Prolonged CEW application on exhausted humans was not associated with worsening change in pH or troponin. Decreases in pCO2 and potassium and a small increase in lactate were found. Worsening acidosis theories due to CEW use in this population are not supported by these data.

Unexpected arrest-related deaths in america: 12 months of open source surveillance

INTRODUCTION

Sudden, unexpected arrest-related death (ARD) has been associated with drug abuse, extreme delirium or certain police practices. There is insufficient surveillance and causation data available. We report 12 months of surveillance data using a novel data collection methodology.

METHODS

We used an open-source, prospective method to collect 12 consecutive months of data, including demographics, behavior, illicit substance use, control methods used, and time of collapse after law enforcement contact. Descriptive analysis and chi-square testing were applied.

RESULTS

There were 162 ARD events reported that met inclusion criteria. The majority were male with mean age 36 years, and involved bizarre, agitated behavior and reports of drug abuse just prior to death. Law enforcement control techniques included none (14%); empty-hand techniques (69%); intermediate weapons such as TASER((R)) device, impact weapon or chemical irritant spray (52%); and deadly force (12%). Time from contact to subject collapse included instantaneous (13%), within the first hour (53%) and 1-48 hours (35%). Significant collapse time associations occurred with the use of certain intermediate weapons.

CONCLUSION

This surveillance report can be a foundation for discussing ARD. These data support the premise that ARDs primarily occur in persons with a certain demographic and behavior profile that includes middle-aged males exhibiting agitated, bizarre behavior generally following illicit drug abuse. Collapse time associations were demonstrated with the use of TASER devices and impact weapons. We recommend further study in this area to validate our data collection method and findings.

Human research review of the TASER electronic control device

TASER Electronic Control Devices have become mainstream methods of applying electricity to control unruly suspects. There has been speculation that they may be associated with worsening human physiology or death. The lay impressions that these devices are unsafe are not founded on known human research findings. This presentation briefly reviews the most pertinent human research on this subject.

Echocardiographic evaluation of a TASER-X26 application in the ideal human cardiac axis

OBJECTIVES

TASER electronic control devices (ECDs) are used by law enforcement to subdue aggressive persons. Some deaths temporally proximate to their use have occurred. There is speculation that these devices can cause dangerous cardiac rhythms. Swine research supports this hypothesis and has reported significant tachyarrhythmias. It is not known if this occurs in humans. The objective of this study was to determine the occurrence of tachyarrhythmias in human subjects subjected to an ECD application.

METHODS

This was a prospective, nonblinded study. Human volunteers underwent limited echocardiography before, during, and after a 10-second TASER X26 ECD application with preplaced thoracic electrodes positioned in the upper right sternal border and the cardiac apex. Images were analyzed using M-mode through the anterior leaflet of the mitral valve for evidence of arrhythmia. Heart rate (HR) and the presence of sinus rhythm were determined. Data were analyzed using descriptive statistics.

RESULTS

A total of 34 subjects were enrolled. There were no adverse events reported. The mean HR prior to starting the event was 108.7 beats/min (range 65 to 146 beats/min, 95% CI = 101.0 to 116.4 beats/min). During the ECD exposure, the mean HR was 120.1 beats/min (range 70 to 158 beats/min, 95% CI = 112.2 to 128.0 beats/min) and a mean of 94.1 beats/min (range 55 to 121 beats/min, 95% CI = 88.4 to 99.7 beats/min) at 1 minute after ECD exposure. Sinus rhythm was clearly demonstrated in 21 (61.7%) subjects during ECD exposure (mean HR 121.4 beats/min; range 75 to 158 beats/min, 95% CI = 111.5 to 131.4). Sinus rhythm was not clearly demonstrated in 12 subjects due to movement artifact (mean HR 117.8 beats/min, range 70 to 152 beats/min, 95% CI = 102.8 to 132.8 beats/min).

CONCLUSIONS

A 10-second ECD exposure in an ideal cardiac axis application did not demonstrate concerning tachyarrhythmias using human models. The swine model may have limitations when evaluating ECD technology.