Pandemic triage plan addresses tough ventilator decisions

Dec 1, 2006 (CIDRAP News) – Canadian infectious disease and critical care experts, working on behalf of Ontario pandemic planners, have developed one of the first triage plans for pandemic influenza.

The protocol is designed to guide clinicians' triage decisions for patients with and without influenza during the first days and weeks of a pandemic when the critical care system is overwhelmed and resources are scarce. The report was published in the November issue of the Canadian Medical Association Journal (CMAJ).

In developing a protocol for pandemic influenza triage, the group used components from other types of triage plans, such as severity scoring systems. The pandemic triage plan has four components: inclusion criteria, exclusion criteria, minimum qualifications for survival, and a color-coded prioritization tool.

The inclusion criteria identify patients who may benefit from critical care treatment, focusing on respiratory failure.

Exclusion criteria place patients in three different categories: those who have a poor prognosis despite critical care, those whose care demands resources that can't be provided during a pandemic, and those who have underlying advanced medical conditions such as malignant cancer or end-stage organ failure that complicates their critical influenza status.

The authors write that they struggled with the decision to put an age cutoff in the plan's exclusion criteria. They did not include one in their original protocol draft because they claim age may not strongly predict critical care outcomes. "However, we received strong and consistent feedback from both expert and stakeholder consultations that an age criterion should be included," they wrote. Age above 85 is listed among the exclusion criteria, but the authors suggest that the topic of age cutoff requires more research and community input.

The "minimum qualifications for survival" component attempts to place a limit on the resources used for any one patient. "This is a concept foreign to many medical systems in developed countries but one that has been used in war zones and refugee camps," the authors write. In the triage protocol, patients are reassessed at 48 and 120 hours to identify early those who are improving and those likely to have a poor outcome.

A tool for prioritizing patients for admission to the intensive care unit (ICU) and access to ventilation is based on a color scheme used for disaster triage plans: blue or black, red, yellow, and green. Patients in the red category have the highest priority for ICU care and ventilation, if needed. Those at the lowest category—blue or black—may receive expectant care or palliative care on the medical ward.

The prioritization tool incorporates the Sequential Organ Failure Assessment (SOFA), which allows emergency department personnel to assign patients a score on the basis of physiologic parameters and simple laboratory tests. The authors write that SOFA scores are easy to calculate and have been validated for a variety of critical care conditions.

"The goal is to optimize the effectiveness of the triage protocol so that every patient who receives resources will survive," say the authors.

Though they consulted a bioethics guide, Stand on Guard for Thee, produced by the University of Toronto Joint Centre for Bioethics, to develop the triage protocol, the authors note that limited resources during a pandemic will mean not all patients receive the intensive care they need. Communities should review, discuss, and refine the protocol before it is implemented in a pandemic setting, they say.

In an editorial in the same issue of CMAJ, two bioethicists from Dalhousie University in Halifax say it isn't clear how bioethics principles shaped the development of the pandemic triage protocol, which they say gives the document a utilitarian focus. "We must be clear why certain values are privileged and others not. This paper contributes to the project, but there is much tough work yet to be done," the editorial states.

They commend the protocol developers for calling for more community involvement but say the document does not address how to accomplish this goal.

John Hick, MD, a disaster medicine expert and emergency medicine physician at Hennepin County Medical Center in Minneapolis, told CIDRAP News that the pandemic triage report contributes to the growing discussion about the decision tools clinicians need in order to make tough decisions about allocating ventilators during a pandemic. He said that while the authors' use of SOFA scoring is justified because it is easier to use than other systems, there are little data about what difference in SOFA score warrants taking one patient's ventilator to give to another who might have a better prognosis.

"Is a difference of 1, 2, or 5 enough to justify such action? At this time, we do not have good guidance," Hick said. "Pandemic-specific epidemiological response to treatment will also have to inform these types of systems," he said, adding that clinicians may have to account for overwhelming mortality for certain age-groups as they use the triage tools.

Hick said it would be useful to know how the authors chose the cutoffs for the triage categories and why they included refractory hemodynamic instability in their inclusion criteria in addition to respiratory failure. "The combination of these two factors alone results in a very high mortality, and the limited inclusion criteria may not 'include' enough patients to aid decisions when many patients require ventilatory support," he said.

Another component of pandemic triage that would be helpful, Hick said, is an assessment of a patient's response to a trial of mechanical ventilation. Such an assessment would help clinicians decide if the patient should remain on the ventilator when resources are scarce, he noted.

Hick said this and other papers that address pandemic triage are useful for helping shape triage decisions and spur more discussion. "There is clearly a need to improve the science of triage and to establish institutional and governmental processes that will facilitate these decisions, regardless of the actual tool or criteria that may be most appropriate for the event."

Christian MD, Hawryluck L, Wax RS, et al. Development of a triage protocol for critical care during an influenza pandemic. CMAJ 2006;175(11):1377-1381 [Full text]

Melnychuk RM, Kenny NP. Pandemic triage: the ethical challenge. (Editorial) CMAJ 2006;175(11):1393 [Full text]

See also:

University of Toronto Joint Centre for Bioethics report on ethical considerations during a pandemic

February Academic Emergency Medicine article on ventilator triage during an epidemic

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