Two approaches ’might be of limited utility in a catastrophic disaster’

Two different approaches to triage for mechanical ventilation showed little agreement, which could be problematic during the Covid-19 pandemic, when there is the potential need to ration such life-saving equipment.

In a retrospective study that compared the two strategies for ventilator allocation — New York State and White and Lo — the former identified 8.9% of patients who would likely meet criteria for the lowest priority for ventilator allocation versus 4.4% with the latter, reported Hannah Wunsch, MD, MSc, of Sunnybrook Health Sciences Centre in Toronto, and co-authors.

Patients who were assigned to the lowest priority level by the guidelines received 2 to 3 days of ventilation, and both guidelines identified a slightly higher percentage of non-white patients as lowest priority, they reported in JAMA Network Open.

And, the two triage approaches identified “substantially different patients for initial consideration for withholding (or very early withdrawal) of mechanical ventilation,” the authors added.

They conceded that “Allocation of life-saving resources in a pandemic is a challenging concept, and many competing interests would be involved in decisions to withhold or withdraw mechanical ventilation. We recognize that the criteria put forth in these guidelines were done so as suggestions rather than as hard-and-fast rules to be adopted across a cohort of patients by using administrative data.”

However, given the current stress on U.S. healthcare facilities — for instance, central California hit max bed-capacity for all the region’s ICUs on December 12, while ventilators have been in short supply in the U.S. since the early days of the pandemic — “the findings are disturbing,” noted Matthew K. Wynia, MD, MPH, of the University of Colorado Anschutz Medical Campus in Denver, in an invited commentary accompanying the study.

“In short, the 2 protocols might be of limited utility in a catastrophic disaster with a severe shortage of ventilators, each prioritized many patients differently, and both might exacerbate underlying racial and ethnic inequities in health care,” he said, and asked what actions should be prompted by the findings.

One solution would be to re-evaluate the use of Sequential Organ Failure Assessment (SOFA) score for crisis triage, and develop “A more accurate triage score, tailored to Covid-19,” Wynia wrote. In July 2020, Wynia and colleague authored a commentary on pathways to a “better survivability triage score.”

While none of the patients in the current study had Covid-19, and the authors did not use the latest version of White and Lo (it was updated in April 2020), the study still “shows why any purely clinical scoring system will put most patients in the highest priority groups… Other values must come into play, at least to break ties,” such as considerations for underserved racial/ethnic groups, Wynia said.

Wunsch’s group used an online database of a random sample of ICU admissions at 208 U.S. They analyzed adult admissions for patients who received mechanical ventilation at any time during an ICU stay from 2014 through 2015. After exclusions, the study cohort consisted of 40,439 ICU admissions who received mechanical ventilation during their stay. Patients had a mean age of 62.6, 75.9% were white, and 54.9% were male.

The study’s primary outcome was the proportion of patients who met the initial criteria for the lowest level of priority for mechanical ventilation using each guideline, both of which start with the SOFA score, and then adds a set of diagnostic and other clinical criteria to determine a patient’s likelihood of in-hospital mortality, the authors explained.

They reported that application of the New York State triage guidelines showed that 5.4% (95% CI 5.2% to 5.6%) of admissions met at least one major comorbidity exclusion criterion, most frequently for refractory or unwitnessed cardiac arrest.

With the White and Lo triage guidelines, 17.7% (95% CI 17.3% to 18.1%) of admissions had at least one major comorbidity exclusion criterion, while 8.7% (95% CI 8.4% to 9%) of patients had a severe life-limiting comorbidity that contributed to their triage priority score, most commonly chronic lung disease and dementia.

Using the New York State criteria, 8.9% (95% CI 8.7% to 9.2%) of patients were classified to the lowest priority category for mechanical ventilation, with the remaining 77.1% (95% CI 76.7% to 77.5%) in the highest priority category.

The lowest priority admissions in the New York State triage criteria had a mean age of 62.9, used a median of 57.3 ventilator hours each, and had a hospital survival rate of 38.6%, according to the authors.

“The New York State criteria overall identified a sicker cohort,” they said. “Because the overall goal of these triage criteria is to minimize allocation of a scarce resource to those who seem least likely to benefit, the New York State criteria appeared closer to achieving this goal.”

With the original White and Lo criteria, 4.3% (95% CI 4.1% to 4.5%) of patients were classified to the lowest priority category for mechanical ventilation and 81.3% (95% CI 80.9% to 81.7%) were assigned to the highest priority category.

The lowest priority admissions in White and Lo had a mean age of 68.6, used a median of 61.7 ventilator hours each, and had a hospital survival rate of 56.2%.

“There was poor agreement between the 2 triage systems regarding which admissions were identified as lowest priority for mechanical ventilation [κ=0.20, 95% CI 0.18 to 0.21], recognizing that the 2 proposed triage systems have unique aims in terms of values for identifying patients,” the authors noted.

Overall, of the 3,612 New York State low-priority ventilator triage admissions and 1,738 White and Lo low-priority ventilator triage admissions, only 1.6% admissions met criteria in both sets of guidelines for the lowest priority category.

As Wynia noted, this was a non-COVID-19 cohort who may have a different distribution than the study cohort. Other limitations included the fact that some of the criteria for comorbidities had to be approximated from based on available data, and only two triage protocols were examined, and only for U.S. patients.

Finally, “We also chose to focus on the triage for mechanical ventilators. However, other equipment, such as dialysis machines, personal protective equipment, and personnel, may be the aspects of care that ultimately are in shortest supply,” Wunsch’s group stated.

  1. Two distinct approaches to triage for mechanical ventilation — New York State and White and Lo — showed little agreement.

  2. Both guidelines identified a slightly higher percentage of non-white patients as lowest priority, suggesting that more clinical assessment of different potential criteria for triage decisions is needed to ensure equitable allocation of resources.

Shalmali Pal, Contributing Writer, BreakingMED™

The study was funding by St Michael’s Hospital Medical Services Association Alternative Funding Plan for COVID.

Wunsch reported no relationships relevant to the contents of this paper to disclose. Co-authors reported relationships with, and/or support from, UpToDate, the Canadian Institutes for Health Research, ALung Technologies, MC3 Cardiopulmonary, Fresenius Medical Care, and Getinge.

Wynia reported involvement in the development of crisis triage protocols for his health system and state, some of which are based in part on SOFA.

Cat ID: 254

Topic ID: 253,254,254,930,791,932,570,573,730,933,190,926,192,927,151,928,925,934