Hypoxicator for aviation training and what are the associated risks?

June 5, 2013 - PRLog -- In the last year correspondence regarding hazards associated with the use of hypoxia for different training interventions were pointed to the absence of reported adverse physiological effects of mild, non-damaging therapeutic hypoxia protocols while using medical grade hypoxia training devices (hypoxicators).

This situation is changing now with the widening use of normobaric hypoxia for other then sports performance enhancement, e.g. for aviation personnel training, aiming to demonstrate their individual hypoxia symptoms and therefore improve aircrew ability of in-flight hypoxia recognition.  

For hypoxia demonstration purposes more severe interventions are used e.g. to simulate gradual aircraft depressurization at 25,000ft. While such training should be conducted under the direct supervision of ACLS accredited person, it does not automatically eliminate the risk of something going wrong.  A recently reported major adverse effect perfectly demonstrates this. Using a fully sealed military oxygen mask a young previously healthy subject was breathing hypoxic air (approx. FiO2=0.07) from an industrial gas mixer (ROBD) for a few minutes, followed by recovery breathing 100% oxygen. Whilst on oxygen, this subject had a loss of consciousness followed by tonic-clonic seizures with subsequent vertebral fractures.  

This reported episode lasted 4 minutes until consciousness gradually returned. This case emphasizes that the used device can significantly alter physiology and be hazardous. However this adverse effect was classified only as a “physiologic event” and no risk mitigation strategy or equipment redesign was recommended in the report.

Why hypoxicators are medical devices?

How to define a device which delivers hypoxic air into a patient’s respiratory system, which is intended to modify physiological process and has attendant risks?  In fact, “hypoxicator” was recently reviewed and it was deemed to be a medical device because “it modifies physiological process”. It was recommended that all hypoxicators are medical device regardless the associated claims. This opinion is in line with the warning of aviation medicine specialists to ensure that the equipment “meets appropriate standards” before it is given the green light “to leave the lab”.  

The role of the regulatory authorities is then to provide an independent evaluation of the safety design and manufacturing of such devices, leading to more efficient corrective action in case adverse effect is reported.

Why the concern?

Hypoxicators were not previously regulated as medical device with an exception of Russia where this officially recognized as a medical technology since 1985.

Because hypoxicators (altitude ‘tents’, ‘rooms’ and ‘mask-based’ systems) were used for years with no tragic events reported, this created a notion of their automatic safety. For example, an altitude tent modified for “aviation training” can easily create an inescapable lethal hypoxic environment by ill-advised users seeking an inexpensive hypoxia training ‘solution’ or by irresponsible manufacturers that are currently do not have a licence to produce medical devices.

How to control the risk?

Regulatory authorities world-wide apply the same principles of classification and control of medical devices: the greater the risk associated with the use of the device – the higher the level of its “classification”.

Concerns were expressed regarding the safety of hypoxicators when used without constant supervision by qualified medical professionals, these concerns were also applied to users who might otherwise be considered healthy individuals.

External expert organisation proposed that: hypoxicator is potentially hazardous; adverse side effects is ”hypoxaemia”; hypoxicators be regulated as medical devices, based on the manufacturer's claims and intended purpose of the product

For more information go to our hypoxic training website