Pneumatic Impedance of Spit Socks and N95 Masks: The Applicability to Death Investigation.

INTRODUCTION: Restrained subjects often spit on law enforcement and corrections officers and medical responders. Based on the droplet-transmitted risk of COVID-19, such spitting could be considered a potentially life-threatening assault. Officers commonly use "spit socks" over the head and neck of spitting subjects to reduce this risk. The pneumatic impedance of such socks has not been published, so this remains an open issue for arrest-related death investigation. METHODS: We purchased samples of 3 popular spit sock models, 3 insect-protecting "bug" socks and hats, 3 N95 masks, a standard 3-ply surgical mask, and a common dust mask. We used a BTmeter model BTN8468 digital anemometer, an HTI model HT-1890 digital manometer, and an AC Infinity Cloudline model S6 inline controllable fan to measure air flow versus pressure drop. We compared the curves graphically and also calculated a pneumatic pseudo-impedance by dividing the pressure drop by the air velocity. RESULTS: The spit and bug socks allowed nearly maximum airflow with minimal pressure (≤1 mm Hg), whereas none of the masks allowed greater than 2 m/s of airflow at maximum pressure of 3 mm Hg. All of the spit and bug masks were grouped together with the lowest pneumatic impedances, whereas all of the N95 masks were grouped together with the highest values. The dust mask and surgical mask were in between with the dust mask closer to the spit and bug masks, whereas the surgical mask was closer to the N95 masks in impedance. CONCLUSIONS: Commonly used spit socks offer nearly zero resistance to breathing. The highest resistance spit sock was still 100 times better than the best N95 mask for airflow during inhalation. Our results do not support the occasional hypothesis that spit socks might contribute to an arrest-related death.

Electrical weapons and excited delirium: shocks, stress, and serum serotonin.

It has been suggested that a CEW (conducted electrical weapon) exposure could elicit a stress response that could cause ExDS (excited delirium syndrome). There are some parallels between the signs of ExDS and serotonin syndrome (SS). Electroconvulsive therapy raises serotonin levels and therefore provides a plausible link between CEW applications and elevated serotonin levels. This study was designed to determine whether a CEW exposure elevates serum serotonin. A total of 31 police academy cadets were exposed to a very broad-spread 5-s CEW stimulus from a TASER brand X26 CEW. Blood was drawn before and after the exposure and at 24 h post exposure to measure serum serotonin levels. Lactic acid and cortisol levels were also compared. Median serum serotonin levels were 30 IQR (21,46), 36 IQR (22,50), and 32 IQR (21,45) ng/mL before exposure, after exposure, and 24 h after exposure (NS by pooled comparisons). The increase from baseline to post-test serotonin (∆ median = +6, ∆ mean = +2.7) ng/mL was not significant by a paired T-test (p = .29) but was significant by the Wilcoxon signed-rank test (p = .037). The increase to post-test log serotonin was not significant by a paired T-test (p = .13) but was significant by the Wilcoxon test (p = .049). All serotonin levels remained within the normal reference range of 0-200 ng/mL. Post-hoc analysis demonstrated that the study was powered to detect a ½ SD change, in log serotonin, with a 90% likelihood. With a very-broad electrode spread, CEW exposure did not significantly raise serum serotonin levels.

Cardiac effects of varying pulse charge and polarity of TASER conducted electrical weapons.

The TASER(R) CEW (Conducted Electrical Weapon) is rapidly replacing the club in the English-speaking world for assisting in the arrest of resistant subjects and is now used by the majority of law enforcement agencies in the USA, Canada, and the UK. Animal safety studies of the CEW have focused on the risk of VF. We sought to determine the difference in cardiac capture and VF risk between the approximately 102 +/- 8 microC of the ubiquitous X26 and a me-tered 72 microC charge from an experimental device. It is well established from the bidomain theory and experimental data that a pacing electrode will capture the heart with significantly lower charge when the electrode touching the cardiac tissue is a cathode However, experimental data show that there is no difference in the ability of the anode vs the cathode to induce VF. We sought to evaluate the effect of polarity changes on cardiac capture and the induction of VF. Small swine ( approximately 20.0 kg) were anesthetized and ventilated. The apex of the heart was located via echocar-diography and a CEW probe was fully inserted towards the apex. Echocardiography was used to monitor cardiac contractions to determine cardiac capture. Both the X26 and the 72 microC pulses were delivered at both polarities to test for cardiac capture. Higher charge pulses (375 microC) were then delivered with both polarities to test for VF risk. The 72 microC experimental unit was unable to cause cardiac capture even in small swine with fully inserted probes directly over the apex of the heart. We found no polarity effect in the risk of VF in small swine with larger charge ( approximately 5x) pulses.