Ventricular fibrillation and blood chemistry from single and multiple TaserX26 discharges on pigs and proposed safety standard.

摘要

The Taser X26 is a hand-held weapon widely used by law enforcement to incapacitate offenders. We developed a mathematical model for it that separates arc and stimulation phases to understand the changes in Taser output electric current with load variations. We found that the Taser current increased with dart depth by performing experiments on saline and pig.;We determined the ventricular fibrillation (VF) time constant for pigs as 2.86 ms +/- 1.90 (SD), which was similar to that for humans (2 ms).;We found the maximum dart-to-heart distance for which VF can occur in pigs with a single 5 s Taser discharge was 17 mm. This distance lies between 10 to 57 mm of skin-to-heart distance in humans recorded by ultrasound and suggests possible human VF.;We found that even if the VF stimulation threshold for a single firing is not reached, multiple firing could still cause VF and is more dangerous than a single Taser firing. Blood samples of pH, K+, Na +, Ca++, PO2 and PCO2 confirmed likely metabolic acidosis in the pigs.;We tested several short-duration electric generators and the Taser to compare their safety parameters with IEC and UL standards for electric fence energizers. We found these calculations difficult to follow and not physiologically relevant. We proposed a new standard to test Taser-like devices, which involves discharging the Taser in an RC circuit with a time constant of about 2 ms and comparing the resulting maximum voltage with a known value to assess its safety. We tested the Taser using the proposed standard under different load conditions. We found the ability of the Taser to depolarize cardiac cells by 20 mV increased by a factor of 2.05 when the Taser darts penetrated 9 mm into load as compared to when they were just touching the load.;We found that carbon deposits on the Taser probe wall determine that electric energy has passed through the probe air gap. No carbon deposits or no melting of the wire insulation cannot be used to determine that no current passed through the probe air gap.