It is inevitable that if an influenza pandemic reaches the scale of some predictions, some patients who, in normal circumstances, would benefit from critical care will not be offered it. Critical care triage will need to evolve from a process of identifying cases who need high level care to one that determines those patients most likely to benefit from the limited resources available and distinguishes them from those where care is likely to be futile. This is recognised by the Emergency Medicine community and the US administration in terms of disaster triage [37, 55] . The American Thoracic Society adopted the utilitarian principle a decade ago, stating that "the duty of health providers to benefit an individual patient has limits when doing so unfairly compromises the availability of resources needed by others" [56] . The problem now facing policymakers and clinicians is defining a process for resource allocation that meets the requirements of distributive justice and accountability for reasonableness [33] . As the Working Group on Emergency Mass Critical Care of the Society for Critical Care Medicine recognised, "an ideal triage system is based on data collected at hospital admission, requires little or no laboratory testing, and has been proven to predict hospital survival" [57] .