William P. Bozeman

Safety and injury profile of conducted electrical weapons used by law enforcement officers against criminal suspects.

STUDY OBJECTIVE Conducted electrical weapons such as the Taser are commonly used by law enforcement agencies. The safety of these weapons has been the subject of scrutiny and controversy; previous controlled studies in animals and healthy humans may not accurately reflect the risks of conducted electrical weapons used in actual conditions. We seek to determine the safety and injury profile of conducted electrical weapons used against criminal suspects in a field setting. METHODS This prospective, multicenter, observational trial tracked a consecutive case series of all conducted electrical weapon uses against criminal suspects at 6 US law enforcement agencies. Mandatory review of each conducted electrical weapon use incorporated physician review of police and medical records. Injuries were classified as mild, moderate, or severe according to a priori definitions. The primary outcome was a composite of moderate and severe injuries, termed significant injuries. RESULTS Conducted electrical weapons were used against 1,201 subjects during 36 months. One thousand one hundred twenty-five subjects (94%) were men; the median age was 30 years (range 13 to 80 years). Mild or no injuries were observed after conducted electrical weapon use in 1,198 subjects (99.75%; 95% confidence interval 99.3% to 99.9%). Of mild injuries, 83% were superficial puncture wounds from conducted electrical weapon probes. Significant injuries occurred in 3 subjects (0.25%; 95% confidence interval 0.07% to 0.7%), including 2 intracranial injuries from falls and 1 case of rhabdomyolysis. Two subjects died in police custody; medical examiners did not find conducted electrical weapon use to be causal or contributory in either case. CONCLUSION To our knowledge, these findings represent the first large, independent, multicenter study of conducted electrical weapon injury epidemiology and suggest that more than 99% of subjects do not experience significant injuries after conducted electrical weapon use.

Quantitative Assessment of Diagnostic Radiation Doses in Adult Blunt Trauma Patients

STUDY OBJECTIVE Many emergency departments and trauma centers utilize extensive radiologic studies during the assessment of trauma patients. A point of concern arises about the possible biological effects of these cumulative radiation doses. The objective of this study is to determine the amount of ionizing radiation received by adult blunt trauma patients at a Level I trauma center during the first 24 hours of their care. METHODS This nonconcurrent case series reviewed the first 100 consecutive adult blunt trauma patients who presented to a Level I trauma center in 2006. All patients met hospital standards for the less acute major triage criteria. Individual radiation dose reports calculated by the computed tomography (CT) scanner were used to determine the radiation doses from each CT procedure. Standardized tables were used to determine radiation dose for plain radiographs. The median effective dose of radiation (millisieverts) was calculated for the first 24 hours of hospitalization. RESULTS A total of 100 eligible patients presented between January 1, 2006, and March 20, 2006. Eighty-six patients had complete radiologic records available. The median age was 32 years, with an intraquartile range of 23 to 46 years; the median Injury Severity Score was 14, with an intraquartile range of 9 to 29; and the median number of CT scans was 3, with an intraquartile range of 3 to 4. The median effective total dose of ionized radiation was 40.2 mSv, with an intraquartile range of 30.5 to 47.2 mSv. A dose of 40.2 mSv is the equivalent of approximately 1,005 chest radiographs. CONCLUSION Trauma patients meeting the less acute major triage criteria are exposed to clinically important radiation doses from diagnostic radiographic imaging during the first 24 hours of their care.

Confirmation of the Pulse Oximetry Gap in Carbon Monoxide Poisoning

STUDY OBJECTIVES To demonstrate the degree to which pulse oximetry overestimates actual oxyhemoglobin (O2Hb) saturation in patients with carbon monoxide (CO) poisoning. This phenomenon has been reported in fewer than 20 humans in the English medical literature. METHODS A retrospective chart review of 191 patients evaluated for CO poisoning at a regional hyperbaric center identified 124 patients 10 years of age and older who had had both arterial blood gas and pulse oximetry measurements and who had received either high-flow oxygen through a nonrebreather mask or 100% inspired oxygen through an endotracheal tube. Blood gas measurements, including direct spectrophotometric determination of O2Hb and carboxyhemoglobin (COHb) saturation values, were compared with finger-probe pulse oximetry readings. RESULTS Measured O2Hb saturation (mean +/- SD, 88.7 +/- 10.2%; range, 51.4% to 99.0%) decreased linearly and predictably with rising COHb levels (10.7 +/- 10.4%; range, .2% to 46.4%). Pulse oximetry saturation (99.2% +/- 1.3%; range, 92% to 100%) remained elevated across the range of COHb levels and failed to detect decreased O2Hb saturation. The pulse oximetry gap, defined as the difference between pulse oximetry saturation and actual O2Hb saturation (10.5% +/- 9.7%; range, 0% to 40.6%), approximated the COHb level. CONCLUSION There is a linear decline in O2Hb saturation as COHb saturation increases. This decline is not detected by pulse oximetry, which therefore overestimates O2Hb saturation in patients with increased COHb levels. The pulse oximetry gap increases with higher levels of COHb and approximates the COHb level. In patients with possible CO poisoning, pulse oximetry must be considered unreliable and interpreted with caution until the COHb level has been measured.

A Comparison of Rapid-Sequence Intubation andEtomidate-Only Intubation in the Prehospital Air Medical Setting

Objectives. To compare laryngoscopy conditions produced by etomidate-only intubation (EOI) with those produced by rapid-sequence intubation (RSI) in the prehospital air medical setting. Methods. A prospective crossover trial design used two helicopters staffed by the same flight paramedics andnurses. Each aircraft used an EOI protocol (0.3 mg/kg) for six months. An RSI protocol using the same dose of etomidate plus succinylcholine (1.5 mg/kg) was used for the alternate six months. Laryngoscopy conditions were graded by three scales: 1) a formal Laryngoscopy Grading Scale (LGS), 2) the Percentage of Glottic Opening (POGO) score, and3) subjective overall intubation difficulty using a Likert scale of 1 (very easy) to 5 (very difficult). Orotracheal intubation success was also recorded. Results. Forty-nine patients were intubated using the EOI (n = 24) andRSI (n = 25) protocols. Mean age was 38 years, 76% were male, and90% were intubated for trauma. Fifteen (63%) of the 24 EOI patients required additional etomidate (n = 3) or RSI (n = 12) to allow intubation, while one (4%) of the 25 RSI patients required additional medication dosing (p < 0.0001). Laryngoscopy conditions were assessed for all patients. Good or acceptable conditions as assessed by the LGS were seen in 79% of RSI patients and13% of EOI patients (p < 0.0001). Mean rates of POGO visualization were 60% with RSI and12% with EOI (p < 0.0001). Mean global intubation difficulty scores were 3.0 (moderate) with RSI and4.7 (difficult to very difficult) with EOI (p < 0.0001). Ninety-two percent of the patients undergoing RSI and25% of the EOI patients were successfully orotracheally intubated (p < 0.0001). Conclusions. Patients receiving RSI had better laryngoscopy conditions andwere easier to intubate than patients receiving EOI. Intubation success rate was higher with RSI.

Excited delirium syndrome (ExDS): Treatment options and considerations

The term Excited Delirium Syndrome (ExDS) has traditionally been used in the forensic literature to describe findings in a subgroup of patients with delirium who suffered lethal consequences from their untreated severe agitation.(1-5) Excited delirium syndrome, also known as agitated delirium, is generally defined as altered mental status and combativeness or aggressiveness. Although the exact signs and symptoms are difficult to define precisely, clinical findings often include many of the following: tolerance to significant pain, rapid breathing, sweating, severe agitation, elevated temperature, delirium, non-compliance or poor awareness to direction from police or medical personnel, lack of fatiguing, unusual or superhuman strength, and inappropriate clothing for the current environment. It has become increasingly recognized that individuals displaying ExDS are at high risk for sudden death, and ExDS therefore represents a true medical emergency. Recently the American College of Emergency Physicians (ACEP) published the findings of a white paper on the topic of ExDS to better find consensus on the issues of definition, diagnosis, and treatment.(6) In so doing, ACEP joined the National Association of Medical Examiners (NAME) in recognizing ExDS as a medical condition. For both paramedics and physicians, the difficulty in diagnosing the underlying cause of ExDS in an individual patient is that the presenting clinical signs and symptoms of ExDS can be produced by a wide variety of clinical disease processes. For example, agitation, combativeness, and altered mental status can be produced by hypoglycemia, thyroid storm, certain kinds of seizures, and these conditions can be difficult to distinguish from those produced by cocaine or methamphetamine intoxication.(7) Prehospital personnel are generally not expected to differentiate between the multiple possible causes of the patients presentation, but rather simply to recognize that the patient has a medical emergency and initiate appropriate stabilizing treatment. ExDS patients will generally require transfer to an emergency department (ED) for further management, evaluation, and definitive care. In this paper, we present a typical ExDS case and then review existing literature for current treatment options.

Emergency Department Evaluation after Conducted Energy Weapon Use: Review of the Literature for the Clinician

BACKGROUND Conductive energy weapons (CEWs) are used daily by law enforcement, and patients are often brought to an emergency department (ED) for medical clearance. STUDY OBJECTIVES To review the medical literature on the topic of CEWs and to offer evidence-based recommendations to Emergency Physicians for evaluation and treatment of patients who have received a CEW exposure. METHODS A MEDLINE literature search from 1988 to 2010 was performed and limited to human studies published from January 1988 to January 20, 2010 for English language articles with the following keywords: TASER, conductive energy device(s), electronic weapon(s), conductive energy weapon(s), non-lethal weapon(s), conducted energy device(s), conducted energy weapon(s), conductive electronic device(s), and electronic control device(s). Studies identified then underwent a structured review from which results could be evaluated. RESULTS There were 140 articles on CEWs screened, and 20 appropriate articles were rigorously reviewed and recommendations given. These studies did not report any evidence of dangerous laboratory abnormalities, physiologic changes, or immediate or delayed cardiac ischemia or dysrhythmias after exposure to CEW electrical discharges of up to 15 s. CONCLUSIONS The current medical literature does not support routine performance of laboratory studies, electrocardiograms, or prolonged ED observation or hospitalization for ongoing cardiac monitoring after CEW exposure in an otherwise asymptomatic awake and alert patient.

Transcardiac Conducted Electrical Weapon (TASER) Probe Deployments: Incidence and Outcomes

BACKGROUND TASER (TASER International, Scottsdale, AZ) conducted electrical weapons (CEWs) are commonly used by law enforcement officers. Although animal studies have suggested that transcardiac CEW discharges may produce direct cardiac effects, this has not been demonstrated in human studies. OBJECTIVES This study sought to determine the incidence and outcomes of transcardiac CEW probe impact locations in a large series of actual CEW deployments. METHODS A multi-center database of consecutive CEW uses by law enforcement officers was retrospectively reviewed. Case report forms were independently reviewed by three investigators to identify cases with paired probe configurations potentially producing a transcardiac discharge vector. Descriptive analysis was performed and inter-rater reliability was assessed. RESULTS Among 1201 total CEW uses, 813 included probe deployments and 178 cases had paired anterior probe impacts potentially capable of producing a transcardiac discharge vector. This represents 14.8% of all CEW uses (95% confidence interval [CI] 12.9-16.9%) and 21.9% of CEW uses in probe mode (95% CI 19.1-24.9%). Inter-rater agreement was very good, with kappa = 0.82. There were no immediate deaths in any cases (97.5% CI 0.0-0.3%) to suggest a cardiac dysrhythmia, including those with transcardiac discharge vector. CONCLUSION CEW deployments with probe impact configurations capable of producing a transcardiac discharge occur in a minority of cases in field use conditions. None of these cases, transcardiac or otherwise, produced immediately fatal dysrhythmias. These data support the overall safety of CEWs and provide a benchmark estimate of the likelihood of transcardiac discharge vectors occurring in field use of CEWs.

Intracranial pressure changes during rapid sequence intubation: a swine model.

BACKGROUND Controversy and speculation exist regarding intracranial pressure (ICP) changes produced by various combinations of rapid sequence intubation (RSI) agents. In this pilot study, we sought to develop a swine model to investigate these changes in classic RSI. METHODS Eight adult swine were instrumented with arterial and intracranial pressure monitors. Four different versions of rapid sequence intubation were then performed sequentially in each animal in a crossover trial design: regimen 1, thiopental; regimen 2, thiopental and succinylcholine; regimen 3, lidocaine, thiopental, and succinylcholine; and regimen 4, pancuronium, lidocaine, thiopental, and succinylcholine. ICP and hemodynamic parameters were recorded and compared. Trials were excluded from analysis if baseline ICP measurements were unstable or if intubation was difficult. RESULTS Peak changes in ICP were noted at 2 to 3 minutes after administration of induction agents. Mean values for peak changes in ICP were as follows: regimen 1 (n = 5), 3.6 mm Hg (95% confidence interval [CI], 1.0-6.2 mm Hg); regimen 2 (n = 9), 13.6 mm Hg (95% CI, 9.6-17.6 mm Hg); regimen 3 (n = 2), 16.0 mm Hg (95% CI, -34.8-66.8 mm Hg); and regimen 4 (n = 3), 12.0 mm Hg (95% CI, -8.3-32.3 mm Hg). CONCLUSION The model is effective. It enables investigators to examine the aggregate ICP effects of combinations of RSI medications. RSI regimens with paralysis produced threefold increases in peak ICP change compared with the sedation-only regimen. Pretreatment agents did not affect ICP changes. Future investigations can examine other agents and add experimental manipulation of ICP to simulate head injury physiology. Additional parameters including cerebral metabolism and/or oxygenation may also be explored.

Association of low non-invasive near-infrared spectroscopic measurements during initial trauma resuscitation with future development of multiple organ dysfunction.

BACKGROUND Near-infrared spectroscopy (NIRS) non-invasively monitors muscle tissue oxygen saturation (StO2). It may provide a continuous noninvasive measurement to identify occult hypoperfusion, guide resuscitation, and predict the development of multiple organ dysfunction (MOD) after severe trauma. We evaluated the correlation between initial StO2 and the development of MOD in multi-trauma patients. METHODS Patients presenting to our urban, academic, Level I Trauma Center/Emergency Department and meeting standardized trauma-team activation criteria were enrolled in this prospective trial. NIRS monitoring was initiated immediately on arrival with collection of StO2 at the thenar eminence and continued up to 24 hours for those admitted to the Trauma Intensive Care Unit (TICU). Standardized resuscitation laboratory measures and clinical evaluation tools were collected. The primary outcome was the association between initial StO2 and the development of MOD within the first 24 hours based on a MOD score of 6 or greater. Descriptive statistical analyses were performed; numeric means, multivariate regression and rank sum comparisons were utilized. Clinicians were blinded from the StO2 values. RESULTS Over a 14 month period, 78 patients were enrolled. Mean age was 40.9 years (SD 18.2), 84.4% were male, 76.9% had a blunt trauma mechanism and mean injury severity score (ISS) was 18.5 (SD 12.9). Of the 78 patients, 26 (33.3%) developed MOD within the first 24 hours. The MOD patients had mean initial StO2 values of 53.3 (SD 10.3), significantly lower than those of non-MOD patients 61.1 (SD 10.0); P=0.002. The mean ISS among MOD patients was 29.9 (SD 11.5), significantly higher than that of non-MODS patients, 12.1 (SD 9.1) (P<0.0001). The mean shock index (SI) among MOD patients was 0.92 (SD 0.28), also significantly higher than that of non-MODS patients, 0.73 (SD 0.19) (P=0.0007). Lactate values were not significantly different between groups. CONCLUSION Non-invasive, continuous StO2 near-infrared spectroscopy values during initial trauma resuscitation correlate with the later development of multiple organ dysfunction in this patient population.

Conducted electrical weapon (TASER) use against minors: a shocking analysis.

Objective Conducted electrical weapons (CEWs) such as the TASER are often used by law enforcement (LE) personnel during suspect apprehension. Previous studies have reported an excellent safety profile and few adverse outcomes with CEW use in adults. We analyzed the safety and injury profile of CEWs when used during LE apprehension of children and adolescents, a potentially vulnerable population. Methods Consecutive CEW uses by LE officers against criminal suspects were tracked at 10 LE agencies and entered into a database as part of an ongoing multicenter injury surveillance program. All CEW uses against minors younger than 18 years were retrieved for analysis. Primary outcomes included the incidence and type of mild, moderate, and severe CEW-related injury, as assessed by physician reviewers in each case. Ultimate outcomes, suspect demographics, and circumstances surrounding LE involvement are reported secondarily. Results Of 2026 consecutive CEW uses, 100 (4.9%) were uses against minor suspects. Suspects ranged from 13 to 17 years, with a mean age of 16.1 (SD, 0.99) years (median, 16 years). There were no significant (moderate or severe) injuries reported (0%; 97.5% confidence interval, 0.0%–3.6%). Twenty suspects (20%; 95% confidence interval, 12.7%–29.1%) were noted to sustain 34 mild injuries. The majority of these injuries (67.6%) were expected superficial punctures from CEW probes. Other mild injuries included superficial abrasions and contusions in 7 cases (7%). Conclusions None of the minor suspects studied sustained significant injury, and only 20% reported minor injuries, mostly from the expected probe puncture sites. These data suggest that adolescents are not at a substantially higher risk than adults for serious injuries after CEW use.