TASER Electronic Control Devices Review Of Safety Literature

from sound velocity in different tissues. The Cleveland Clinic measured the skinto-heart
spacing in 45 patients. 55 In the BMI (body-mass-index) range seen with
custodial deaths, 41 the minimum spacing found was 22 mm. Even if an XP (Extended
Penetration) 13 mm barb was used and a perfect orientation and penetration
was established the tip-to-heart spacing would still be 9 mm which is twice
the required 4 mm spacing to induce VF in a human.
In 2006 Nanthakumar et al presented a study of TASER ECDs using 6 pigs averaging
50 kg (110 lb). 56 In the worst-case barb position they achieved some
ventricular capture but induced no arrhythmias during 94 full strength applications.
They then infused epinephrine and shortly later delivered 16 ECD applications
— again in the worst-case position. They had 1 case of VF from these 16
applications. The authors concluded that these devices may have cardiac risks.
While perhaps counterintuitive, epinephrine reduces the VF threshold only for the
first few minutes. 57 After that the VF threshold is increased significantly above
the baseline. This timing is helpful for the clinical scenario. Typically, an individual
exhibits violent agitation with hyperactivity 58 for several minutes and third parties
call for help. The law enforcement officers and EMS (emergency medical
services) normally require 5-15 minutes to arrive before they can capture and
control the individual and apply any restraint device. At this point, the adrenergic
tone has been elevated for several minutes. An epinephrine infusion just minutes
before an ECD application would appear to give results opposite of those seen in
real life.
In February 2007, Dr. Nanthakumar published a clarification 59 stating:
We did not state that [ECDs] cause ventricular fibrillation in humans, and
we agree that we cannot conclude from our study that [ECD] discharges
cause arrhythmias in typical use.
Other studies have found occasional inductions of VF in small swine with chest
applications. 60,61 A meta-analysis of all published swine studies (which include a
large variation of weights) show that the risk of VF is confined to the lower
weights. 62 See Figure 9.
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