The purpose of this contribution, and the following four related editorials, is to address from different viewpoints some of the clinical and ethical guidelines that are of concern to physicians involved with the difficult decision of what and how much to do for the patient with chronic obstructive lung disease in whom severe respiratory failure develops. These discussions, however, are also applicable to the management of respiratory failure associated with other forms of lung disease, and also to life-threatening problems that are unrelated to the respiratory system. Each of these physician-commentators may be striving to follow the Hippocratic injunction: "First, do no harm." On reading these essays, it becomes clear that the means to achieve that goal are neither obvious nor easy to find.
To place matters in perspective, acute and chronic diseases of the respiratory system are now the most common causes of morbidity and mortality in the United