Classic cases revisited - Oxygen in court and the problem of therapeutic illusion.

Medical science attempts to inform clinical practice. Law is concerned with causality. Intersection of law and medicine at times highlights the shortcomings in the medical approach to causality. Evidence-based medicine is only as good as the process of gathering evidence and this is inherently imperfect as suggested by philosophers. There is a risk of attributing a causal relationship when there is none, which can result in a false belief about an intervention. False beliefs can become entrenched forming a dogma. An application of treatment and a subsequent observation of clinical improvement may create a therapeutic illusion of benefit. It is possible that oxygen is used in this way. We cannot safely infer based on harm associated with its deprivation that supplementation of oxygen is beneficial in all patients. Evidence of benefit of oxygen therapy versus harm is not overwhelmingly convincing. The case of oxygen serves to illustrate a potential for a wider problem in science and medicine where potentially harmful treatments are administered based on beliefs rather than evidence and on the extrapolations from population-wide observations and without considering particulars of each case. Current application of oxygen is possibly inappropriate and efforts should be made to reappraise its use.