Modern medicine offers us a vast range of diagnostic and therapeutic techniques, and the cost-effective use of these is one of the greatest challenges facing the clinician. In some of the more recently introduced and complex clinical areas, such as non-invasive mechanical ventilation (NIV), it is not uncommon to hear opinions voiced that may be not only debatable and confusing, but may even lead to dubious or inappropriate treatment, including the following approaches:

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  Discuss local procedures and protocols without providing results from the overall population.

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  Conclusively recommend unproven indications for NIV, e.g., in patients with stable chronic obstructive pulmonary disease or obesity hypoventilation syndrome.

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  Accept the sum of individual practices as a general criterion for indication.

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  Propose the positive benefits seen in a patient subgroup as a criterion for indication, even when the overall results of the study are negative.

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  Assume that the results of observational studies represent the best evidence.

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  Fail to consider that actions have both organizational and financial consequences.

Variability in clinical practice is a problem that has been recognized for years.1 It is also true that clinical practice is constructed not only from scientific evidence but also from local circumstances, professional skills and patient values.2 Decision-making is a complex issue, and it is clear that certain specific problems need to be managed with prescriptions that are not strictly in line with established protocols: this is the realm of compassionate use. A certain degree of flexibility is necessary to stimulate innovation, but it is surprising to see data from the Respiratory Therapy Observatory of Catalonia suggesting that NIV prescription in patients over 65 years of age can vary as much as 40-fold between areas of minimum and maximum prescription.

It is important to remember that professional credibility depends on the consistency of shared values. Sharing real world results, not only those from clinical trials, accepting compassionate treatments for what they are, without converting them into a canon for daily practice, and the critical review of collective clinical practices are key elements in consolidating this credibility. Moreover, credibility is essential if we are to set an example for new generations and contribute to the sustainability of the public health system. This is an area in which scientific societies must be the first to engage in self-criticism and adapt to the demands of our times, in which the practice of medicine should always be evidence-based. Prescribing physicians must be aware of their responsibilities when indicating procedures in the absence of such evidence. Professional credibility, transparency and self-regulated discretion will enable us to meet today's challenges and the needs of our patients.