Public debate in Britain about moral differences between helping someone to die and withdrawing or withholding treatment can only help patients and their doctors, says a specialist from the standpoint of ethics and decision making in end stage lung disease.

Two well known cases—those of Miss B and Mrs Diane Pretty—have highlighted issues around mechanical ventilation. It has been argued that they are similar philosophically and the divisive decisions applied to each arose from purely legalistic argument.

Doctors are bound by oath not to harm. They must weigh up the likely outcome of treatment against burden for the patient and quality of life. When expectations conflict—as in doctors’ underestimates of survival in chronic lung disease versus patients’ overoptimism—they complicate joint decisions about the end of life.

Good communication, not just about outcome, is crucial. Too often patients are not told about the burden of treatment despite guidelines and research evidence that this does influence their decisions.

Doctors have a duty to keep abreast of new treatments and their potential. Non-invasive ventilation can extend options. However, a quarter of doctors did not discuss these in neuromuscular disease, believing that suffering would be prolonged, according to one survey—unhelpful when other studies show that such patients’ quality of life is consistently underestimated. Nevertheless, assisted ventilation can be maleficent, and doctors should respect competent patients’ wishes to refuse treatment or ask it to be withdrawn. “Living wills” are a way of patients recording their wishes and doctors must abide by them.