The utilitarian rule of maximizing the number of lives saved is widely accepted during a public health emergency.(18
) The Ontario and New York working groups both propose modifying a relatively simple mortality prediction model- the Sequential Organ Failure Assessment score(19
)-to determine an individual's priority. There is no compelling evidence that one mortality prediction model will be more accurate than another, but the Sequential Organ Failure Assessment score is the easiest to implement and requires the fewest laboratory tests. Although existing models are imperfect, they are as accurate as physicians' prognostic estimates(20
) and have the added appeal of being objective and transparent. Prioritizing individuals according to their chances for short term survival also avoids ethically irrelevant considerations-such as race or socioeconomic status. Finally, it is appealing because it balances utilitarian claims for efficiency with egalitarian claims that because all lives have equal value, the goal should be to save the most lives.(18
However, using the probability of short term survival as the sole
allocation principle is problematic. It is hazardous to extrapolate mortality prediction models beyond the conditions for which they have been validated. (20
) Perhaps because of this concern, existing guidelines recommend using the Sequential Organ Failure Assessment score only to stratify people into 4 prognostic groups, rather than to make finer distinctions among patients. Based on current experience with avian influenza, it is probable that many patients with respiratory failure will also develop multi-organ failure.(22
) Thus, there likely will be large clusters of patients who are indistinguishable based on their prognoses for short term survival.
Ethically, using only chances of survival to hospital discharge is insufficient because it rests on a thin conception of “accomplishing the greatest good”. Below, we discuss additional principles that have been used in other situations to allocate scarce medical resources. We argue that two of these principles should be combined with the principle of “saving the most lives” to create a multi-principle strategy to allocate scarce life saving resources during a public health emergency.
Broad Social Value
Broad social value refers to one's overall worth to society. It involves summary judgments about whether an individual's past and future contributions to society's goals merit prioritization for scarce resources.(18
) When dialysis was first introduced, social value was a key consideration in allocating scarce dialysis machines. Patients who were professionals, heads of families, and caregivers received priority over “creative non-conformists who rub the bourgeoisie the wrong way”.(23
) The public firestorm in response to revelations that social worth was a key factor in the Seattle Dialysis Committee's deliberations partly led Congress to authorize universal coverage for hemodialysis.(24
In our morally pluralistic society, it has not been possible to agree upon a set of criteria to assert that one individual is intrinsically more worthy of saving than another. Even if such consensus could be reached, some philosophers argue that it should not be a guiding principle for allocation decisions. These individuals defend the egalitarian view that all individuals have an equal moral claim to treatment regardless of whether they can contribute measurably to broad social goals. (25
) Childress writes that one's “dignity as a person…cannot be reduced to his past or future contribution to society.”(26
) Given the lack of an accepted specification of broad social value and the sharp disagreement about whether it is a relevant consideration, we do not recommend using this principle to guide allocation of life support during a public health emergency.
Instrumental Value: The “Multiplier Effect”
Instrumental value refers to an individual's ability to carry out a specific function that is essential to prevent social disintegration or a great number of deaths during a time of crisis. It has also been described as “narrow social utility” and the “multiplier effect”.(18
) The National Vaccine Advisory Committee recommends this principle to allocate vaccines and anti-viral medications during a pandemic.(28
) It gives first priority to workers in vaccine manufacturing and health care provider. The ethical justification is that prioritizing certain key individuals will achieve a “multiplier effect” through which many more lives are ultimately saved by their work.
Instrumental value must be distinguished from judgments about broad social worth. Individuals are prioritized not because they are judged to hold more “intrinsic worth”, but because of their ability to perform a specific task that is essential to society. In this sense, instrumental value is a derivative allocation principle; it is desirable because it ensures an adequate workforce to achieve public health goals. Even critics of allocation based on broad social value accept the use of instrumental value in certain circumstances.(25
However, using instrumental value may be ethically problematic for some public health emergencies, such as an influenza pandemic, which likely will be short in duration and leave individuals with illnesses that require a long recovery period. In general, to justify a restrictive public health measure, there must be good evidence that the measure is necessary
and will be effective
) It seems unlikely that individuals with respiratory failure from influenza would recover in time to re-enter the work force and fulfill their instrumental roles. Moreover, it is not clear which roles are truly indispensable to saving a large number of lives during a pandemic. Because of the uncertainty about which key personnel will be in short supply and whether they will recover in time to achieve their instrumental value, we do not recommend that this principle be incorporated at this stage of planning. However, this principle should be openly debated with the public and “held in reserve” if convincing evidence emerges that its use would minimize mortality in a particular public health emergency.
Several other allocation principles can be rejected without extensive discussion. “First-come, first-served” and “sickest first” are inconsistent with the public health goal of achieving the greatest good for the greatest number. Maximizing quality-adjusted life years (QALYs) or disability-adjusted life years (DALYs) would not be feasible to implement during a public health crisis.(29
) We next turn to two principles that can and, we contend, should be combined with the principle of “saving the most lives” to allocate life saving resources during a public health emergency.
A broader conceptualization of accomplishing the “greatest good” is to consider the years of life saved in addition to the number of lives saved. Assuming equal chances of short term survival, giving priority to a 60-year old woman who is otherwise healthy over a 60 year-old woman with a limited life expectancy from severe comorbidities will result in more “life years” gained. The justification for incorporating this utilitarian claim is simply that, all other things being equal, it is better to save more years of life than fewer.
The principle of maximizing life years was recently incorporated into the strategy to allocate lungs for transplantation. Rather than simply aiming to save the most lives, the lung allocation system now balances patients' medical need (prognosis without transplantation) against their expected duration of survival after transplantation.(31
) We contend that explicitly adding considerations of “maximizing life-years saved” to “saving the most lives” yields a more complete specification of accomplishing the greatest good for the greatest number. Although current guidelines use this principle to exclude certain subgroups of patients from access to treatment, we think that this principle is relevant to all patients, not just those with extremely limited life expectancies. Moreover, applying it to all patients rather than an unfortunate few promotes consistency and fairness.
The Life Cycle Principle
Under the life cycle principle, the goal is to give each individual equal opportunity to live through the various phases of life.(32
) This principle has been call the “fair innings” argument and “intergenerational equity”.(33
) In practical terms, the life cycle principle gives relative priority to younger individuals over older individuals. There is a precedent for incorporating life cycle considerations into pandemic planning. The DHHS's plan to allocate vaccines and anti-virals during an influenza pandemic prioritizes infants and children over adults.(28
)The ethical justification of the life cycle principle is that it is a valuable goal to give individuals equal opportunity to pass through the stages of life-childhood, young adulthood, middle age, and old age.(32
) The justification for this principle does not rely on considerations of one's intrinsic worth or social utility. Rather, younger individuals receive priority because they have had the least opportunity to live through life's stages.
Empirical data suggest that, when individuals are asked to consider situations of absolute scarcity of life sustaining resources, most believe younger patients should be prioritized over older.(34
) Harris summarizes the moral argument in favor of life cycle-based allocation as follows, “it is always a misfortune to die…it is both a misfortune and a tragedy [for life] to be cut off prematurely”.(35
Some critics contend that the life cycle principle unjustly discriminates against older individuals. However, this principle is inherently egalitarian because it seeks to give all individuals
equal opportunity to live a normal life span. It applies the notion of equality to individuals' whole lifetime experiences
rather than just to their current situation.(33
) Unlike prioritization based on gender or race, everyone faces the prospect of aging and everyone hopes to move through all stages of life.(32
Can multiple principles be incorporated into an allocation strategy?
Prior success in developing multi-principle allocation systems for organ transplantation suggests that this is a feasible endeavor.(31
) However, during a public health crisis, there will be little time for complex algorithms. Undoubtedly, there will be a tension between creating an allocation strategy that reflects the moral complexity of the issue and one that can be feasibly implemented. We propose an alternative to the single principle strategy proposed by previous working groups that strives to incorporate and balance saving the most lives, saving the most life-years, and giving individuals equal opportunity to live through life's stages.
describes one example of a very basic approach to specifying and incorporating these three principles into an allocation strategy. It is meant to be illustrative rather than definitive. Each principle is assessed on a 4-point scale. Individual patients are evaluated based on their likelihood of short-term survival, presence of comorbidities that would limit the duration of benefit, and their “phase of life”. Patients with the lowest cumulative score would receive the highest priority for scarce, life sustaining technologies. We make no claim that this specific unweighted point system is the optimal way to balance and translate these three allocation principles into practice. Another approach is to treat each principle as a continuous variable and weight them according to judgments about their relative importance. There are complex value judgments that underlie decisions to weight principles differently or arrange them hierarchically. Although these value judgments ultimately must be made, the first step- which is the goal of this article- is to establish that there are several relevant allocation principles. Thereafter, we should engage key stakeholders to determine how to fairly balance these principles.
Illustration of a Multi-Principle Strategy to Allocate Ventilators during a Public Health Emergency
To illustrate how the proposed multi-principle system leads to different allocation decisions compared to the “save the most lives” approach, consider the vignette presented in . Using the “save the most lives” strategy proposed by New York State, Ontario, and the Critical Care Initiative, the 83 year-old man with a 50% chance of hospital survival, but multiple life-limiting co-morbidities (which are not on the proposed lists of categorically excluded diseases) would receive highest priority. Even though the previously healthy 44 year-old man has a much better long-term prognosis and has had the least opportunity to live through life's stages, he is ranked less favorably because of his slightly worse prognosis for survival to hospital discharge. The patient with primary pulmonary hypertension and an accidental overdose would be categorically denied ventilation because her disease is on the list of exclusion criteria which are not clearly justified.(9
) The latter patient's case highlights the mistaken assertion that patients with severe comorbidities should be categorically denied life support on the grounds that they will always have poor ICU outcomes.
In contrast, the multi-principle allocation strategy we propose would result in priority going to the 32 year old patient with pulmonary hypertension with a 90% chance of short term survival. She is prioritized above the other 2 patients because of the combination of her excellent chances for short term survival and her young age (total allocation score: 5). The previously healthy 44 year old patient with no comorbidities and a 30% chance of short term survival (total allocation score 6) is prioritized over the 83 year old with severe comorbidities and 50% chance of short-term survival (total allocation score 11) even though he has a worse prognosis for short term survival. Although not relevant in these sample cases, patients with identical allocation scores should be viewed as having equal moral claims to receive life support. In such a circumstance, a lottery is a reasonable approach to determine which patient will receive priority.
Some may criticize the proposed multi-principle system as overpenalizing older individuals, who are more likely to have more co-morbidities and to have lived through life's stages. However, the multi-principle system we propose draws an important distinction between healthy older adults and older adults with life limiting co-morbidities. This approach avoids using age as a “blunt” predictor of years of life remaining. Rather than over-penalizing older adults for the correlation between age and co-morbidities, our system avoids “penalizing” healthy older adults. Others may criticize such a system for relying on probabilities of outcomes which may not accurately predict what will happen to any one individual. We acknowledge that any probabilistic scoring system cannot perfectly predict outcomes for individual patients. This concern has limited the use of probabilistic scoring systems to make treatment decisions during routine clinical practice.(11
) However, the rationale for their use is stronger during a public health emergency, when the goal is to maximize population-level outcomes. Such an objective approach may also be viewed by the public as fairer than decisions based on more subjective criteria.
Although more complex than the previously proposed single principle allocation system, we believe that this multi-principle allocation system better reflects the diverse moral considerations relevant to these difficult decisions. In addition, this approach avoids the need to categorically deny treatment to certain groups, a problem that one legal scholar calls a “political and legal minefield”.(36