Page 44 - JSOM Summer 2024

TABLE 1 Oxygen Concentration Measurements
Position of Sensor distance Sensor position Oxygen flow Duration of oxygen Measured oxygen
room door Oxygen source from source from source* meter rate, LPM flow, min concentration, %
Open Room air Room air N/A 0 0 19.4
Open Wall outlet Contact Contact 15 0 98
Open Wall outlet Contact Contact Flush 0 100
Closed Mask In Mask In mask Flush 5 98.3
Closed Mask 6 in 9 o’clock Flush 15 20.5
Closed Near mask 6 in 12 o’clock Flush 15 31.5
Closed Near mask 6 in 4 o’clock Flush 15 20.1
Flush rate is approximately 40–60LPM.
LPM = liters per minute.

TABLE 2 Ignition of Combustible Materials During Conducted Electrical Weapon (CEW) Electrical Current Exposure
CEW dart separation Oxygen
distance, inches Combustible material tested concentration, % Ignition
6 Cotton gown, surgical paper drape, cotton gauze, human hair 25, 35, and 45 No
1.5 Cotton gown, surgical paper drape, cotton gauze, human hair 25, 35 No
1.5 Cotton gown, surgical paper drape, cotton gauze 45 No
1.5 Human hair 45 Yes

(typically ambient oxygen), and ignition. While room air oxy- A worst-case clinical interpretation of this is a patient with long
gen concentrations (21%) support combustion, elevating this scalp or facial hair present on non-rebreather mask oxygen at
concentration lowers the threshold for combustion to occur the maximal flow rate receiving CEW dart deployment to the
and thus can elevate the risk of ignition and fire. As oxygen face at point-blank range. This is an unlikely scenario since a
concentration increases, autoignition temperature decreases patient requiring maximal oxygen support is unlikely to require
and materials that may not readily ignite and burn under room CEW deployment for violence control. Additionally, the head is
air conditions, may more easily do so in oxygen-rich settings. In not a recommended target for CEW deployment, and trained
a patient care setting, the common presence of clothing/gowns, CEW users are taught to not intentionally target this area. 13
hair, gauze, and other items such as sterile draping (fuel) along
with supplemental oxygen (oxidizer) and a CEW arc (ignition) This study has applicability for TEMS operators and non-
could provide all components necessary for a combustible TEMS personnel as well, especially if care is being given in an
reaction. enclosed space such as the back of a vehicle like an ambulance
or a tactical vehicle. For example, the back of an ambulance
The CEW represents a unique potential ignition source within represents an enclosed space where a CEW could be used in
a patient care setting. Its use is discouraged by some in this set- the setting of supplemental oxygen. Both TEMS and non-
ting because of the perception of enhanced danger because of TEMS field care occurs in potentially violent situations. 14,15
the presence of supplemental oxygen. This work addresses that These situations occur quite often in the presence of CEW-
perception by finding that danger to be quite low. The risk is armed personnel. It is conceivable that a CEW could be used
not zero in this setting but appears to be remote because of the in an enclosed ambulance environment (e.g., law enforcement
narrow circumstances needed to support ignition. First, high officers accompanying a patient to the hospital). We believe
concentrations of oxygen are necessary. We found an oxygen that our findings would hold true for the back of an enclosed
concentration of 45% or greater was needed for the CEW arc space such as an ambulance.
to ignite hair on a simulated patient. Even at maximal sup-
plemental oxygen flow rates, it was not possible to achieve Special areas of enhanced flammability extend to non-TEMS
that high an oxygen concentration in an enclosed room farther environments as well. Oxygen concentrations above 45% may
than 6 inches (15.24cm) from the oxygen source. Additionally, be found in specialized treatment areas such as hyperbaric ox-
even at an oxygen concentration of 45%, human hair was the ygen chambers. However, since this type of treatment area is
only combustible item tested that readily ignited. sealed when in use, having a CEW inside it when operating is
not conceivable. An operating room could be another area of
This study supports that the highest risk of CEW ignition/ concern, where gaseous anesthetics, which are known to be
fire in the setting of supplemental oxygen would require the highly flammable, are used in addition to supplemental ox-
following: ygen. However, operating rooms tend to be secure areas to
1. Oxygen source flowing at maximal “flush” rate. maintain sterility standards, and visitors (representing poten-
2. Dart deployment at very close range (darts from most com- tially violent persons) are generally excluded from entering.
monly used CEW models deploy at approximate 8° angles Additionally, a patient in the operating room is unlikely to
of separation so landing them within 1.5 inches (3.81cm) need subdual from a CEW since they should be unresponsive
of each other requires deployment from nearly point-blank owing to anesthesia. Based on these factors, we believe that
range). CEW use in these areas would be extremely rare.
3. Darts landing within 6 inches (15.24cm) of maximally
flowing supplemental oxygen. An important finding of this study is that the circumstances
4. Presence of hair at dart landing site. needed for a CEW to initiate ignition in the patient care setting

42 | JSOM Volume 24, Edition 2 / Summer 2024