Chemical oxygen generation: Evaluation of the Green Dot Systems, Inc portable, nonpressurized emOx device

To evaluate the performance of the emOx emergency powdered oxygen portable nonpressurized delivery system. This device produces oxygen through chemical reaction and is marketed for emergency first aid use until professional medical assistance is available.

Seven unmanned trials were conducted under standard laboratory conditions. Measures included oxygen flow, reaction canister external wall temperature, delivered gas temperature, and delivered gas relative humidity.

The mean oxygen flow was 1.75 ± 1.58 L x min(-1) (mean ± SD) with a total yield of 40.4 ± 2.6 L. Oxygen flow increased slowly and with substantial variability between reactant groups, exceeding 2.0 L x min(-1) after 15.7 ± 6.4 minutes of operation. Oxygen flow briefly peaked at 5.93 ± 0.56 L x min(-1) at 17.8 ± 7.9 minutes before rapidly falling to zero. The mean oxygen fraction was 0.81 ± 0.28, exceeding 0.96 in 10.7 ± 2.9 minutes. The reaction canister external wall temperature reached 54.7 ± 7.4 °C. Delivered gas temperature varied little from ambient. Delivered gas relative humidity surpassed 75% in 8 ± 3 minutes and 90% in 15 ± 5 minutes of operation.

A readily available, high concentration oxygen supply could have utility to manage many conditions in advance of the arrival of professional emergency medical services (EMS). Unfortunately, the highly variable activation time and low average oxygen flow rate make the rapid deployment value of the emOx equivocal. The limited total oxygen yield makes it inappropriate for conditions demanding significant oxygen resources. Advancement in oxygen concentrator systems likely holds far more promise than powdered chemical oxygen generation for first aid and emergency medical applications.