No Pressure

(Airwaves Issue 4 December 2007)

In June this year, five staff from the Christchurch Air Retrieval Service travelled to Auckland to experience first hand, what life is like without oxygen at 18,000 feet.
  
Many aviation accidents have been linked to pilots and aircrew becoming hypoxic due to insidious pressurisation failures in aircraft travelling at altitude. The flight crew become hypoxic and tragically unable to respond appropriately to ensure their own safety.  Educating flight crew and showing them how they individually react to becoming hypoxic helps ensure that the condition is recognised early. Steps can then be taken to remedy the situation before the crew becomes incapacitated.

On the 19th June, five staff from the Christchurch Air Retrieval Service travelled to Auckland to attend the inaugural hypoxic training day at Clarke House on the edges of the Whenuapai Airbase in Auckland.

The course was run by staff from the New Zealand Air Force Hypobaric Medicine Unit and the NZ Flight Nurses Association. Flight teams from all around the country were represented.

Lectures were presented by both Air Force and Navy medical staff covering pressure effects with altitude and depth.  While the lectures were informative and entertaining the main event of the day was the opportunity to experience supervised runs in the hypobaric chamber.  The recently re-commissioned chamber had been used by the air force since the 1960’s to train pilots to recognise the effects of hypoxia (a lower than normal concentration of oxygen in the tissues and organs) with altitude and to give them first hand experience of being hypoxic.

The chamber runs involve being “taken to” 18,000 feet where the oxygen percentage is approximately half of that at sea level.  The participants were then taken off oxygen for 10 minutes and asked a series of questions taken from the lectures and asked to perform some mental arithmetic.  The same process was performed at 25000 feet for a period of 2-3minutes.   All of the participants soon experienced the effects of being hypoxic, with colours dimming, and a gradual mental slow down that in some cases led to complete confusion. Both chamber runs were medically supervised and expert support crew in the chamber remained on oxygen to provide emergency assistance.

The day was rounded out with a look at the new aero medical retrieval platform currently being developed by the air force for use in all its aircraft.

This study day provided a truly unique experience that gave all participants valuable insight into this potential danger. Being able to recognize the early signs will equip our flight crew to ensure we react quickly and appropriately to prevent possible tragedy.

Support from the Canterbury West Coast Air Rescue Trust and Garden City Helicopters was vital and very much appreciated by all of our medical and nursing staff who were able to attend this training.