The era of “benign paternalism” is over. Clinicians are now required to ensure the active participation of individual patients in decisions relating to their treatment, and their education regarding risks and benefits of diagnostic and therapeutic interventions. Except in those rare cases where disclosure of risk is likely to cause serious harm, clinicians must now attempt to ensure that patients are fully informed.

The obtaining of appropriately informed and well documented consent helps the process of developing trust between patient and clinician. Of developing importance is the defensive role played by the same process, when distressed or litigious patients suffer significant complications; this is especially so where outcomes involve serious long term consequences. In these cases, defective or inadequately documented consent procedures may provide relatively straightforward routes to successful claims. To succeed in law, claimants may have to do no more than demonstrate, on a balance of probability, that they have not been adequately counselled, and that had they been so counselled, they would not have undergone the procedure in question. While this represents a formidable hurdle in the case of urgent intervention such as life saving surgery for cyanotic congenital heart disease, it is one more easily surmounted in the case of elective procedures such as diagnostic cardiac catheterisation.

It is important to note that in certain circumstances a patient may provide only limited consent. For example, a patient may consent to coronary angiography but specifically refuse angioplasty. A patient may consent to major surgery but clearly reject the transfusion of blood or blood products. Clinicians agreeing to proceed under such restrictions must respect the patient's wishes. Except for measures that are both unforeseen and necessary in order to save life or prevent irreversible damage, no additional measures may be taken without obtaining consent beforehand.