Large-scale health catastrophes from infectious causes (for example, influenza, the severe acute respiratory syndrome), natural disasters (for example, tsunamis, earthquakes, hurricanes), or terrorist attacks can overwhelm the capabilities of health care systems and have the potential to stress and even change the traditional norms of the patient–physician relationship. For example, physicians may unavoidably conduct triage. Furthermore, many state, national, and international bodies have issued reports on health catastrophes that include recommendations for unilateral physician decisions to withhold and withdraw mechanical ventilation from some patients who might still benefit from it, when the demand for ventilators exceeds supply (37 - 40). The guiding principles for health care delivery during catastrophes may shift from autonomy and beneficence to utility, fairness, and stewardship (Figure). One reports notes that “[a] public health disaster such as a pandemic, by virtue of severe resource scarcity, will impose harsh limits on decision-making autonomy for patients and providers” (37). Physicians together with public and governmental organizations should participate in the development of guidelines for the just delivery of health care in times of catastrophe, being mindful of existing health disparities that may affect populations or regions.