Unravelling ADM (Aeromedical Decision Making)

Aeromedical Decision Making (ADM) is a paradigm, a template and a tool. ADM as a paradigm presently consciously practiced by Civil Aviation Authority, New Zealand; and it is a logical template to be applied by other regulators as well, while it is a useful tool in the hands of Aviation Medical Examiners (AME).

To unravel ADM, one needs to first understand that this is an amalgamation of two concepts: evidence-based medicine (EBM) and structured risk management. The aim of ADM, in the context of regulatory medical licensing, is to ensure assessment of individual fitness for aviation duties without compromising the aviation safety. Meaning thereby, that irrespective of the fitness awarded, the possibility of subtle or sudden incapacitation in flight is not likely to jeopardize the safety of flight, with existing safety measures in place: be it the presence of a second pilot, or applying the prevalence rates of illness/disease in the population, or aircraft automation like audio-visual warnings or auto-pilot, or applying the airmanship or crew resource management principles or any other safety mechanism. It must be understood though, that while evaluating a disability, the available safety mechanism listed above are not considered (except applying the 1% rule for multi-crew operations only), except the professional responsibilities of the pilot under assessment; however the restrictions imposed on the pilot, in case of disabilities, may consider the safety mechanisms listed above.

Let us first understand the concept of Risk Management [1]. The broad elements of Risk Management are:  establishing the context, risk assessment (by identification, analysis and evaluation) and risk treatment. These elements of Risk Management are continuously governed by two vital processes throughout: “monitoring and review” and “communication and consultation” [1]. Without delving into these self-explanatory concepts, it is important to understand that this paradigm of systematic risk management is useful for the ADM as well. In case of ADM, acceptable parameters are required for defining the context, broad risk assessment is undertaken by identifying/defining the risks requiring observation/ intervention/management, to enable the analysis of the disease/disability, its management and the operational (read aviation) environment; for an evaluation of acceptable or non-acceptable risks under operational environment, to finally define the flying fitness (unrestricted or with limitations) or denial of it.

Now to answer as to how does EBM help in ADM? It is said that “the practice of evidence based medicine means integrating individual clinical expertise with the best available external clinical evidence from systematic research” [2]. Furthermore, it is “the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients” [2]. It is important here to understand the broad meaning of the word ‘care’ in the context of aviation regulatory functions. It starts with the AME and the individual’s family/general physician (if both are not the same, which may be the case many a times) who have to responsibility of offering the best available treatment in case of a disease/disability to their pilot-patient. It then extends to the medical regulators, who determine the status of such an individual pilot for determining his/her fitness for aviation duties. To quote, Sackett et al, “Increased expertise is reflected in many ways, but especially in more effective and efficient diagnosis and in the more thoughtful identification and compassionate use of individual patients’ predicaments, rights, and preferences in making clinical decisions about their care [2]”. This has to be extended, where the vital principles of EBM viz. individual patient’s predicaments, rights and preference, need to be applied by the regulators while evaluating fitness of a pilot. It is important that EBM is applied holistically by all concerned and not in an arbitrary or piece meal manner. Therefore, it has to become a conscious practice by all those who are party to the ADM process determining the medical fitness of pilots for aviation duties.

There are certain pitfalls in applying ADM, the biggest being the absence of evidence pertaining to the niche population of pilots. But as 1% rule, initially propounded for assessment of cardiovascular morbidity based on the data from the age and sex matched population Viagra [3], has proven its usefulness as a rule of thumb in determining the fitness in case of multi-crew operations; it is envisaged that the principles of ADM, if applied earnestly, shall provide fair, just and transparent outcomes. Thus ADM, in the context of the regulatory purposes, is to align itself with the due scientific basis of EBM within the structured risk management paradigm. So also it is the onus of the AME/medical licensing authority to apply the current best evidence, within the structured risk management processes to provide the “reasonable, replicable and reviewable” [4] fitness outcomes for the benefit of the individual pilot without compromising aviation safety.

References

1. ISO 31000: 2009: Risk Management Principles and Guidelines [Abstract at http://www.iso.org/iso/catalogue_detail?csnumber=43170]

2. Sackett DL, Rosenberg WMC, Gray JAM, Hynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. BMJ 1996; 312: 71.

3. Evans ADB. International regulation of medical standards. In Rainford DJ, Gradwell DP (editors) Ernsting’s Aviation Medicine. Fourth Ed. Hodder Arnold: London; 2006: 547-566.

4. Watson DB. Aeromedical decision-making: an evidence-based risk management paradigm. Aviat Space Environ Med 2005; 76: 58-62.