REPEATED THORACIC DISCHARGES FROM A STUN DEVICE Daniel J. Valentino MD,1,2 Robert J. Walter PhD,1,2 Kimberly Nagy MD,1,2 Andrew J. Dennis DO,1,2 Jerry Winners BS,1 Faran Bokhari MD,1,2 Dorion Wiley MD,1,2 Azher Merchant BS,2 Kimberly Joseph MD,1,2 and Roxanne Roberts MD1,2 2

1 Department of Trauma, Stroger Hospital of Cook County, Chicago, IL 60612 Department of General Surgery, Rush University Medical Center, Chicago, IL 60612

ABSTRACT

Figure 4

RESULTS

CK-MB Concentration

Background: Stun guns or Electromuscular Incapacitation Devices (EIDs) generate between 25,000 and 250,000 volts and can be discharged continuously for as long as 5-10 minutes. In the US, over 200,000 individuals have been exposed to discharges from the most common type of EID used. EIDs are being used increasingly despite a lack of objective laboratory data describing the physiological effects and safety of these devices. An increasing amount of morbidity, and even death, is associated with EID use. We hypothesized that exposure to thoracic EID discharges in a model animal system would induce clinically significant acidosis and cardiac arrhythmia.

¾Heart rate (Figure 2) and blood pressure were not significantly affected by MK-63 discharge.

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¾No evidence of acute arrhythmia or myocardial injury was found (Figure 3). Mean CK-MB (Figure4) and TnI (Figure 5) levels were not significantly affected by MK-63 discharge (oneway ANOVA p>0.05).

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Methods: Ten Yucatan mini-pigs, 6 experimentals and 4 sham controls, were anesthetized with ketamine, xylazine, and glycopyrollate. Experimentals were exposed to two 40 sec discharges from an EID device (MK63, Aegis Indus.) over the left thorax. EKGs, troponin I, blood gases, and lactate levels were obtained preexposure, at 5, 15, 30, 60 min, 24, 48 and 72 hrs post-discharge.

¾A moderate, significant increase in lactate occurred at 5 min post-discharge (Figure7).

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¾MK-63 discharge did not significantly affect serum electrolyte levels. Neither potassium nor creatinine values exceeded normal levels at any time point.

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¾No clinically significant acidosis was seen with MK-63 discharge (Figure 6).

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Figure 5 TnI Concentration

Figure 2 Heart Rate

0.150

Figure 5. At the 24 hr time point, the TnI value rose in both controls and experimentals, but TnI returned to baseline values for both groups subsequently. The observed increase in experimentals, however, was not statistically significant when compared to controls (p=0.695) or to baseline levels for the experimental group.

Avg 80s thorax Avg Control

0.110 150 140

Avg 80s thorax Avg Control

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Conclusions: Although significant changes in some parameters were seen, these changes were small and of little clinical significance. Lengthy EID exposures did not cause extreme acidosis or cardiac arrhythmias. These findings may differ from those seen with other EID devices due to the unique MK63 waveform characteristics or to specific characteristics of the model systems.

48 h

Time after Electrical Discharge

0.130

Results: No acute or delayed cardiac arrhythmias were seen. Heart rate was not affected significantly (p>0.05). A subclinical increase in troponin I was seen at 24 hrs post-discharge (0.040±0.030 ng/ml, mean±SEM, p>0.05). Central venous blood pH (7.432±0.014) and pCO2 (36.1±0.9 mmHg) were not changed significantly (p>0.05) during the 60 min post-discharge period. A moderate, significant increase in lactate occurred in the 5 min post-discharge group (4.9±0.3 mmol/L, p=0.0179). All blood chemistry and vital signs were normal at 24, 48, and 72 hrs post-discharge.

Figure 4. CK-MB concentration (mean ± SEM) did not rise significantly at any time in either group. The control group showed some variability with time, but the differences between the control and experimental groups were not significant (one-way ANOVA).

Avg 80s thorax Avg Control

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Figure 2. Heart rate (mean ± SEM) showed an initial decrease 5 min after discharge but was maintained between 100 and 120 bpm at all time points in the experimental group. None of these variations were statistically significant (p>0.05)

0.090 0.070 0.050 0.030 0.010 -0.010 0 min

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Figure 6

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Figure 3 Representative EKGs

Central Venous pH 7.650

Avg 80s thorax Avg Control

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INTRODUCTION

Pre-Discharge

7.500 7.450 7.400

Figure 6. No significant changes in pH were seen. Similarly, the changes in pCO2 and bicarbonate showed only small changes correlating with the observed changes in blood pH.

7.350

¾EIDs generate between 25,000 and 250,000 volts and can be discharged continuously for as long as 5-10 minutes. In the US, over 200,000 individuals have been exposed to discharges from the most common type of EID used.

5 min Post-Discharge

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Figure 7

¾More than 250 fatalities have occurred since 1999 that were associated with EID use in the US. ¾The effects and safety of these discharges on living organisms are poorly understood and their ability to induce cardiovascular injury or arrhythmia is poorly understood.

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15 min Post-Discharge

Lactate Concentration 6.0

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5.0

Figure 7. Lactate in experimentals showed a small increase at 5 min. This was not statistically significant (p>0.05) vs baseline values. The experimental group showed significantly higher levels of lactate when compared to controls (oneway ANOVA, p<0.05).

Avg 80s thorax Avg Control

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MATERIALS

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Lab Simulator with E-Pod Inserted E-Pod with Electrode Cap Attached

E-Pod Electrode Cap

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Figure 1. E-Pod and MK-63 lab simulator. The e-pod was placed over the left mid-clavicular line at the level of the 4th or 5th rib and discharges were administered with the electrodes oriented parallel to the cardiac axis from the base of the heart to its apex for a total of 80 sec.

48 hr Post-Discharge 72 hr Post-Discharge

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CONCLUSIONS

¾ No evidence of acute or delayed cardiac arrhythmia or biochemical evidence of cardiac injury was seen. ¾ No electrolyte abnormalities were detected.

Figure 3. No evidence of acute arrhythmia was detected during, immediately post-discharge, or at later time points post-discharge. No arrhythmias were observed in any animal at any time point.

¾ This study shows that even lengthy discharges from the MK-63 do not cause significant cardiac injury or acid base/electrolyte disturbances. 1. 2. 3. 4.

STUDY LIMITATIONS Anesthetized animal model used. Limited animal numbers. Resting animals, no excitatory stimuli (e.g., epinephrine) or drugs (methamphetamine, cocaine, etc.) used. One trans-cardiac vector studied.

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