TASER Electronic Control Devices Review Of Safety Literature

This gives a safety margin of 74:1 = 140 mA ÷ 1.9 mA for the X26 and M26.
Beigelmeier Model: 74:1 Safety Margin
Beigelmeier’s model holds that long-term AC (5 seconds or more) requires 1/20 th
of the current to fibrillate as does a single 20 ms (millisecond) pulse (which single
pulse would have to be into the T-wave). 17 The single pulse VF threshold can be
predicted from the Jones and Geddes study which found a ratio of 52:1 for a 10
ms pulse (the widest pulse they investigated). This would give a single 10 ms
pulse a VF threshold of 1.4 A = 52 • 27 mA.
Dividing this by Beigelmeier’s ratio of 20 gives a predicted AC threshold of
70 mA. Doubling this for humans gives a human threshold of 140 mA and a
safety margin of:
74:1 for the TASER X26 and TASER M26
(which matches the results from the Knickerbocker model)
Dalziel Model: 84:1 Safety Margin
In the 1960s Dalziel performed a meta-analysis of VF thresholds for mammals. 38
This is shown in Figure 8. This includes the animal fibrillation data from Ferris
dating back to the 1930s. 39 Conservatively, Dalziel included swine which are very
easy to fibrillate due to subtle cardiac conduction system differences. 40
The average current required to cause fibrillation is given by the formula:
I = 3.68 W + 28.5 mA
Where W is the body weight in kg. For lbs (pounds) the formula is:
I = 1.67 W + 28.5 mA
For a typical excited delirium arrest-related death of 200 lbs (91 kg) 41 the average
current required to fibrillate would be:
I = 362 mA
which gives an average safety margin of 191:1. However, Dalziel recognized that
sensitivities to electrical currents vary and he thus performed a statistical analysis.
He plotted the lower limit of sensitivity as the middle line in the figure. Note
that this middle line gives a fibrillating current of over 170 mA for a 200 lb resisting
human subject. This gives:
Safety margin
= 170 mA ÷ 1.9 mA
= 89:1
30