Do Saliva-Saturated Spit Hoods Interfere With Ventilation?

ABSTRACT: Spit hoods are used by law enforcement, officers in correctional facilities, and medical personnel during the restraint of agitated subjects that are actively spitting to prevent the transmission of droplet-transmitted pathogens. We could find no studies reporting on the time course of normal breathing to clear saliva from such a saturated spit hood. We purchased samples of 3 popular spit hood models and applied a section over the output of a pneumatic test system. We used a digital anemometer, digital manometer, and an inline controllable fan for back pressure and flow. The pressure was 3 mm Hg to match quiet breathing. The tested area was saturated with artificial saliva, and air pressure was applied while we recorded the pressure and airflow. Within 5 seconds, the spit hoods all cleared sufficient artificial saliva to allow 1 m/s of airflow, which exceeds that of an N95 mask with similar pressure. Commonly used spit hoods offer very low resistance to breathing even after being initially saturated with artificial saliva. Our results do not support the hypothesis that a saliva-filled spit hood might contribute to death.

The Mechanism of Death in Electrocution: A Historical Review of the Literature.

ABSTRACT: Our present understanding of electrocution followed a long path of detours and speculation. It is now hard to appreciate how mysterious was an unexpected sudden death-without visible trauma-and we should be sympathetic to the surprising theories that came from well-intentioned attempts to find something in the autopsy of an electrocution victim.The early hypotheses (1880s) tended to favor effects on the central nervous system, but the emphasis switched to arterial and hematological mechanisms as well as respiratory arrest (ie, asphyxia) along with a widespread publication debate. While careful animal experimentation slowly established that electrocution was due to the induction of VF (ventricular fibrillation), the older hypotheses held sway for many decades. Even today, the neurogenic and asphyxial explanations reappear occasionally.Despite 170 years of research, the phenomenon of electrocution continues to generate new hypotheses for its mechanism.

Homicide Manner-of-Death Classification in Arrest-Related Death.

ABSTRACT: Multiple studies have documented various factors that influence or determine forensic pathologist classification of manner of death. There do not appear to be any published studies on manner of death classification specifically regarding arrest-related deaths (ARDs). The goal of this study was to consider a large body of cases of nonfirearm ARDs to analyze the homicide classification with regards to numerous decedent and practitioner (medical examiner/coroner [ME/C]) variables. We analyzed 1145 US autopsy reports from the years 2006-2020, inclusive, and considered decedent variables of age, ethnicity, height, weight, body mass index, toxicology, and mention of a conducted electrical weapon and ME/C influence variables of gender, country region, and year. We found that the homicide classification likelihood increased by a factor of 1.04-1.05 per year, 1.34-1.37 for a female medical examiner, and 1.4-1.5 going from Southern states to Western states. There is an increasing trend for ME/C to label nonfirearm ARDs as homicides in the United States. The homicide classification is more common in Western states and less common in Southern states, and it was more common with a female ME/C.

Pneumatic Impedance of Spit Socks and N95 Masks: The Applicability to Death Investigation.

INTRODUCTION: Restrained subjects often spit on law enforcement and corrections officers and medical responders. Based on the droplet-transmitted risk of COVID-19, such spitting could be considered a potentially life-threatening assault. Officers commonly use "spit socks" over the head and neck of spitting subjects to reduce this risk. The pneumatic impedance of such socks has not been published, so this remains an open issue for arrest-related death investigation. METHODS: We purchased samples of 3 popular spit sock models, 3 insect-protecting "bug" socks and hats, 3 N95 masks, a standard 3-ply surgical mask, and a common dust mask. We used a BTmeter model BTN8468 digital anemometer, an HTI model HT-1890 digital manometer, and an AC Infinity Cloudline model S6 inline controllable fan to measure air flow versus pressure drop. We compared the curves graphically and also calculated a pneumatic pseudo-impedance by dividing the pressure drop by the air velocity. RESULTS: The spit and bug socks allowed nearly maximum airflow with minimal pressure (≤1 mm Hg), whereas none of the masks allowed greater than 2 m/s of airflow at maximum pressure of 3 mm Hg. All of the spit and bug masks were grouped together with the lowest pneumatic impedances, whereas all of the N95 masks were grouped together with the highest values. The dust mask and surgical mask were in between with the dust mask closer to the spit and bug masks, whereas the surgical mask was closer to the N95 masks in impedance. CONCLUSIONS: Commonly used spit socks offer nearly zero resistance to breathing. The highest resistance spit sock was still 100 times better than the best N95 mask for airflow during inhalation. Our results do not support the occasional hypothesis that spit socks might contribute to an arrest-related death.

Confusion between firearms and electrical weapons as a factor in police shootings.

Conducted electrical weapons (CEW) have risks including trauma associated with uncontrolled falls, probes penetrating the eye, and fume ignition. A lesser-known risk is weapon-confusion error with officers mistakenly discharging their firearm when they intended to deploy their electrical weapon. We searched for incidents of possible weapon confusion with the TASER® brand CEWs via open-source media, litigation filings, and a survey of CEW law enforcement master instructors. We found 19 incidents of possible CEW weapon confusion in law enforcement field uses from January 2001 to April 2021. We eliminated a case as not meeting our criteria for probable weapons confusion leaving 18 cases, thus giving a demonstrated CEW discharge risk of 3.9 per million with confidence limits (2.4-6.2 per million) by Wilson score interval. Ipsilateral carry of the weapons was historically correlated with increased risk vs. contralateral carry. Officer gender was not a predictor of weapon confusion. The psychological issues behind weapon confusion under stress are discussed. The concurrent carry of electrical weapons and firearms presents a very small but real risk of injury and death from confusion between an electrical weapon and a firearm.

Police shootings after electrical weapon seizure: homicide or suicide-by-cop.

PURPOSE: Risks of handheld electrical weapons include head impact trauma associated with uncontrolled falls, ocular probe penetration injuries, thermal injuries from the ignition of volatile fumes, and weapon confusion police-involved shooting. There is also an uncommon but critical risk of a shooting after a subject gained control of an officer's electrical weapons. METHODS: The authors searched for police shooting incidents involving loss of control of TASER® weapons via open-source media reports, crowd-sourced internet sites, litigation filings, and a survey of Axon law-enforcement master instructors. RESULTS: The authors report 131 incidents of subjects attempting to or gaining control of an officer's electrical weapon from 2004 to 2020, 53 of which resulting in a shooting. These incidents demonstrated a risk of 11.8 shootings per million electrical weapon discharges (95% confidence limits of 9.0 to 15.1 per million by Wilson score interval). CONCLUSIONS: The use of electrical weapons presents a rare but real risk of injury and death from a shooting following a subject's attempts to gain control of the weapon.

Electrical weapons and rhabdomyolysis.

It has been suggested that an application of a conducted electrical weapon (CEW) might cause muscle injury such as rhabdomyolysis and an acute inflammatory response. We explored this hypothesis by testing the effects of electrical weapons on circulating markers of inflammation and muscle damage. In a prospective study, 29 volunteers received a full-trunk 5-s TASER® X26(E) CEW exposure. Venous blood samples were taken before, 5 min after, and at 24 h following the discharge. We tested for changes in serum levels of C-reactive protein (CRP), alkaline phosphatase (ALP), myoglobin, albumin, globulin, albumin/globulin ratio, aspartate and alanine aminotransferase, creatine kinase, total protein, bilirubin, and lactic acid dehydrogenase. Uncorrected CRP and myoglobin levels were lower in the immediate post exposure period (CRP levels 1.44 ± 1.39 v 1.43 ± 1.32 mg/L; p = 0.046 and myoglobin 36.8 ± 11.9 v 36.1 ± 13.9 µg/L; p = 0.0019) but these changes were not significant after correction for multiple comparisons. There were no changes in other biomarkers. At 24 h, CRP levels had decreased by 30% to 1.01 ± 0.80 mg/L (p = 0.001 from baseline). ALP was unchanged immediately after the CEW application but was reduced by 5% from baseline (66.2 ± 16.1 to 62.7 ± 16.1 IU/L; p = 0.0003) at 24 h. No other biomarkers were different from baseline at 24 h. A full-trunk electrical weapon exposure did not lead to clinically significant changes in the acute phase protein levels or changes in measures of muscle cellular injury. We found no biomarker evidence of rhabdomyolysis.

Eye injury from electrical weapon probes: Mechanisms and treatment.

PURPOSE: While generally reducing morbidity and mortality, TASER® electrical weapons have risks associated with their usage, including burn injuries and head and cervical trauma associated with uncontrolled falls. The primary non-fatal complications appear to be significant eye injury but no analysis of the mechanisms or suggested treatments has been published. METHODS: We used a biomechanical model to predict the risk of eye injury as a function of distance from the weapon muzzle to the eye. We compared our model results to recently published epidemiological findings. We also describe the typical presentation and suggest treatment options. RESULTS: The globe rupture model predicted that a globe rupture can be expected (50% risk) when the eye is within 6 m of the muzzle and decreases rapidly beyond that. This critical distance is 9 m for lens and retinal damage which is approximately the range of the most common probe cartridges. Beyond 9 m, hyphema is expected along with a perforation by the dart portion of the probe. Our prediction of globe rupture out to 6 m (out of a typical range of 9 m) is consistent with the published risk of enucleation or unilateral blindness being 69 ±â€¯18%, with an eye penetration. CONCLUSIONS: Significant eye injury is expected from a penetration by an electrical weapon probe at close range. The risk decreases rapidly at extended distances from the muzzle. Not all penetrating globe injuries from electrical weapon probes will result in blindness.

Perceived Electrical Injury: Misleading Symptomology Due to Multisensory Stimuli.

BACKGROUND: An electrical accident victim's recollection is often distorted by Bayesian inference in multisensory integration. For example, hearing the sound and seeing the bright flash of an electrical arc can create the false impression that someone had experienced an electrical shock. These subjects will often present to an emergency department seeking either treatment or reassurance. CASE REPORTS: We present seven cases in which the subjects were startled by an electrical shock (real or perceived) and injury was reported. Calculations of the current and path were used to allocate causality between the shock and a history of chronic disease or previous trauma. In all seven cases, our analysis suggests that no current was passed through the body. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Symptomology seen as corroborating may actually be confounding. Witness and survivor descriptions of electrical shocks are fraught with subjectivity and misunderstanding. Available current is usually irrelevant and overemphasized, such as stress on a 100-ampere welding source, which is orders of magnitude beyond lethal limits. History can also be biased for a number of reasons. Bayesian inference in multisensory perception can lead to a subject sincerely believing they had experienced an electrical shock. Determination of the current pathway and calculations of the amplitude and duration of the shock can be critical for understanding the limits and potential causation of electrical injury.

Applied Force During Prone Restraint: Is Officer Weight a Factor?

INTRODUCTION: It has been suggested that law enforcement officer (LEO) weight on the backs of prone subjects may cause asphyxia. METHODS: Law enforcement officers used their agency-trained "local" single- and double-knee techniques, the "Wisconsin" 3-Point Ground Stabilization, and the Human Factor Research Group Inc single-knee tactical handcuffing techniques, and the weight force was measured. RESULTS: Forty-one LEOs (36 men, 5 women) participated, aged 38.4 ± 8.3 years, and weighing 96.2 ± 19.4 kg. The double-knee technique transmitted more weight than single knee (P < 0.0001). Wisconsin technique force was lower than other single-knee techniques (P < 0.0001). Double-knee weight was 23.3 kg plus 24% of LEO's body weight. Mean values for local and Human Factor Research Group Inc single-knee were 30.9 and 32.9 kg, respectively. The Wisconsin single knee weight force was given by 15.4 kg plus 9.5 kg for a male. CONCLUSIONS: A double-knee technique applies more weight force than single-knee techniques. The Wisconsin single-knee technique provides the least weight force of single-knee techniques. Law enforcement officer body weight is irrelevant to prone-force weight with single-knee techniques. With double-knee restraint, it has a modest influence. Our data do not support the hypothesis of restraint asphyxia.

Cardiac and skeletal muscle effects of electrical weapons : A review of human and animal studies.

Conducted Electrical Weapons (CEWs) are being used as the preferred non-lethal force option for police and special forces worldwide. This new technology challenges an exposed opponent similarly to the way they would be challenged by physical exercise combined with emotional stress. While adrenergic and metabolic effects have been meta-analyzed and reviewed, there has been no systematic review of the effects of CEWs on skeletal and cardiac muscle. A systematic and careful search of the MedLine database was performed to find publications describing pathophysiological cardiac and skeletal muscle effects of CEWs. For skeletal muscle effects, we analyzed all publications providing changes in creatine kinase, myoglobin and potassium. For cardiac effects, we analyzed reported troponin changes and arrhythmias related to short dart-to-heart-distances. Conducted electrical weapons satisfy all relevant electrical safety standards and there are, to date, no proven electrocution incidents caused by CEWs. A potential cardiovascular risk has been recognized by some of the experimental animal data. The effects on the heart appear to be limited to instances when there is a short dart-to-heart-distance. The effect on the skeletal muscle system appears to be negligible. A responsible use of a CEW on a healthy adult, within the guidelines proposed by the manufacturer, does not imply a significant health risk for that healthy adult.

Electrical weapons and excited delirium: shocks, stress, and serum serotonin.

It has been suggested that a CEW (conducted electrical weapon) exposure could elicit a stress response that could cause ExDS (excited delirium syndrome). There are some parallels between the signs of ExDS and serotonin syndrome (SS). Electroconvulsive therapy raises serotonin levels and therefore provides a plausible link between CEW applications and elevated serotonin levels. This study was designed to determine whether a CEW exposure elevates serum serotonin. A total of 31 police academy cadets were exposed to a very broad-spread 5-s CEW stimulus from a TASER brand X26 CEW. Blood was drawn before and after the exposure and at 24 h post exposure to measure serum serotonin levels. Lactic acid and cortisol levels were also compared. Median serum serotonin levels were 30 IQR (21,46), 36 IQR (22,50), and 32 IQR (21,45) ng/mL before exposure, after exposure, and 24 h after exposure (NS by pooled comparisons). The increase from baseline to post-test serotonin (∆ median = +6, ∆ mean = +2.7) ng/mL was not significant by a paired T-test (p = .29) but was significant by the Wilcoxon signed-rank test (p = .037). The increase to post-test log serotonin was not significant by a paired T-test (p = .13) but was significant by the Wilcoxon test (p = .049). All serotonin levels remained within the normal reference range of 0-200 ng/mL. Post-hoc analysis demonstrated that the study was powered to detect a ½ SD change, in log serotonin, with a 90% likelihood. With a very-broad electrode spread, CEW exposure did not significantly raise serum serotonin levels.

Defibrillation thresholds with right pectoral implantable cardioverter defibrillators and impact of waveform tuning (the Tilt and Tune trial).

AIMS: Assess defibrillation thresholds (DFTs) with right active pectoral implantable cardioverter defibrillator (RICDs). Defibrillation thresholds in patients receiving RICDs are regarded as 'high' and potentially improved by waveform optimization (tuning). However, this has not been systematically tested. METHODS AND RESULTS: Patients receiving RICDs [Single chamber (VVI) = 16, DDD = 32, cardiac resynchronization therapy (CRT) = 43] were randomized to either 50/50% fixed tilt (FT) or tuned waveform (3.5 ms time constant based). Defibrillation threshold was tested with a binary search protocol in single coil anodal configuration. Then RICDs were compared with left-sided placements. Baseline patient characteristics in FT (n = 54) and tuned (n = 37) were similar (65 ± 14 years, 71% male, Left ventricular ejection fraction 31 ± 13%; and proportions VVI/DDD/Cardiac resynchronization therapy defibrillator). Tuning reduced Phase 1 by 15% and Phase 2 by 45%. For FT vs. tuned: high voltage impedance was 61.9 ± 13.2 vs. 64.5 ± 12.7 Ω (P = 0.33) and mean DFT 14.2 ± 8.8 vs. 14.9 ± 9.2 J (P = 0.8). When high voltage impedance was >62 Ω (mean 73.6 ± 8.6 Ω), DFT was identical [FT 13.0 ± 7.9 J vs. tuned 12.0 ± 5.9 J (P= 0.7)]. Defibrillation thresholds exceeded 20 J (600 V) in >20% of patients [FT 11/54 (20.4%) vs. tuned 12/37 (32%) patients]. Defibrillation threshold with RICD was greater and exhibited wider dispersion compared with left ICDs (n = 54) under similar conditions. CONCLUSION: This first randomized trial investigating DFTs with right ICDs confirms relatively higher DFTs with RICDs than reported for left pectoral ICDs. However, DFTs were generally unaffected by 3.5 ms time constant-based waveform tuning compared with a 50% tilt waveform. Implant testing may be preferred with RICDs. CLINICAL TRIAL NUMBER: NCT00873691.

Reducing ICD Test Shocks with a Simplified Upper Limit of Vulnerability.

BACKGROUND: Determination of an adequate defibrillation safety margin or defibrillation threshold can be a challenge in patients with implantable defibrillators (ICDs). The upper limit of vulnerability (ULV) has been shown to be highly correlated with measured defibrillation thresholds. The peak of the latest peaking monophasic T wave measured from the pacing spike of the induction train of S1 via the surface electrocardiogram (ECG) is generally accepted to approximate the vulnerable period of the cardiac cycle. OBJECTIVES: The purpose of this study was to determine whether a single electrogram-derived coupling interval could provide an accurate determination of the vulnerable period for a simplified test method to approximate the defibrillation safety margin. METHODS: We used a single electrogram-derived coupling interval for the timing of the T shock. We compared the measured intracardiac electrogram coupling interval to the latest peaking T wave on the surface ECG. RESULTS: A total of 72 patients were studied: single-chamber ICD (n = 28), dual-chamber ICD (n = 26), or cardiac resynchronization therapy-defibrillator (n = 18). The coupling intervals were greater on the electrograms versus the surface ECG: 365 ms ± 27 versus 347 ms ± 26 (P < 0.0001). Almost all of the patients tested, 69/72 (96%), were indeed defibrillated with the T-shock energy that failed to induce ventricular fibrillation (VF). Only three (4%) of the patients failed the hypothesis when 500 V failed to induce VF but subsequently also failed to defibrillate a forced induction of VF. CONCLUSIONS: A simplified ULV testing protocol, using a single electrogram channel, accurately separates low from high defibrillation threshold testing patients.

A Model of Electrostimulation Based on the Membrane Capacitance as Electromechanical Transducer for Pore Gating.

BACKGROUND: Electrostimulation has gained enormous importance in modern medicine, for example, in implantable pacemakers and defibrillators, pain stimulators, and cochlear implants. Most electrostimulation macromodels use the electrical current as the primary parameter to describe the conventional strength-duration relationship of the output of a generator. These models normally assume that the stimulation pulse charges up the passive cell membrane capacitance, and then the increased (less-negative) transmembrane potential activates voltage-gated sodium channels. However, this model has mechanistic and accuracy limitations. NOVEL CONCEPT: Our model assumes that the membrane capacitance is an electromechanical transducer and that the membrane is compressed by the endogenous electric field. The pressure is quadratically correlated with the transmembrane voltage. If the pressure is reduced by an exogenous field, the compression is released and, thus, opening the pores for Na(+) influx initiates excitation. RESULTS: The exogenous electric field must always be equal to or greater than the rheobase field strength (rheobase condition). This concept yields a final result that the voltage-pulse-content produced by the exogenous field between the two ends of a cell is a linear function of the pulse duration at threshold level. Thus, the model yields mathematical formulations that can describe and explain the characteristic features of electrostimulation. CONCLUSIONS: Our model of electrostimulation can describe and explain electrostimulation at cellular level. The model's predictions are consistent with published experimental studies. Practical applications in cardiology are discussed in the light of this model of electrostimulation.

Incapacitation recovery times from a conductive electrical weapon exposure.

PURPOSE: Law enforcement officers expect that a TASER(®) CEW (Conducted Electrical Weapon) broad-spread probe exposure will temporarily incapacitate a subject who will then be able to immediately (~1 s delay) recover motor control in order to comply with commands. However, this recovery time has not been previously reported. METHODS: A total of 32 police academy students were exposed to a very broad-spread 5 s CEW stimulus as part of their training and told to depress a push-button as soon as they sensed the stimulus. A subgroup also depressed the push-button after being alerted by an audio stimulus. RESULTS: The response time after the audio trigger was 1.05 ± 0.25 s; the median was 1.04 s (range 0.69-1.34 s). For the paired CEW triggered group the mean response time was 1.41 ± 0.61 s with a median of 1.06 s (range 0.92-2.18 s), which was not statistically different. Only 2/32 subjects were able to depress the button during the CEW exposure and with delays of 3.09 and 4.70 s from the start. Of the remaining 30 subjects the mean response time to execute the task (once the CEW exposure ended) was 1.27 ± 0.58 s with a median of 1.19 s (range 0.31-2.99 s) (NS vs. the audio trigger). CONCLUSIONS: With a very-broad electrode spread, a CEW exposure could prevent or delay some purposeful movements. Normal reaction times appear to return immediately (~1 s) after the CEW exposure ceases.

The electrophysiology of electrocution.

Electrocution is a death caused by an application of electrical current to the human body. Our present understanding of electrocution-as the induction of ventricular fibrillation (VF)-followed a nearly century-long path of misunderstandings and speculation primarily focused on hypotheses of asphyxia as well as central nervous system trauma. It is hard for us today to appreciate the past mystery of an unexpected sudden death usually bereft of visible trauma. Even today, a false dogma exists that direct-current shocks can cause asystole instead of VF. A lightning discharge (up to 500 megavolts) is differentiated because it can cause substantial acute and chronic neural effects leading to other cardiac arrest rhythms. The human heart is exquisitely sensitive to alternating currents, and VF can be induced with currents of one-eighth that required for mere pacing. Because of these low currents, this effect obtains only in the TQ interval, and low-power electrocution does not involve the vulnerable period. If a current is strong enough to electrocute, generally it will do so in 1-2 seconds; longer shocks do not tend to be more dangerous. Regardless of concomitant drug dosing, the electrocution cardiac arrest rhythm is still VF, suggesting that electrocution is a stand-alone cause of death; the electrical current does not potentiate the effects of the drug. The experimental and clinical data supporting VF as the mechanism for electrocution are provided.