Performance of influenza-specific triage tools in an H1N1-positive cohort: P/F ratio better predicts the need for mechanical ventilation and critical care admission

Abstract

The P/F ratio was a better predictor of need for mechanical ventilation than STSS. The P/F ratio is a simple and accepted determinant of hypoxaemia and should be used if secondary triaging becomes necessary during future influenza pandemics.

Triage during pandemic influenza: seeking absolution in numbers?

“…[3][4][5][6][7] There is little doubt that the profession has benefited from such monitoring of performance, but the true beneficiaries of clinical governance have been our patients. 6 An article published Editorials | 867…”

“…Indeed, even at a unit population level they are outperformed by the subjective judgement of clinicians. 12 The receiver operating characteristic curves in the study reported in this edition 7 illustrate the problem with these triage tools. Whilst the diagnostic performance is good, with an area under curve of >0.8 for the best-performing measures, even at the optimal cut-off the measures are some considerable distance from 100% sensitivity and specificity for admission to intensive care, let alone prediction of mortality.…”

“…In this edition of the BJA, Morton and colleagues 7 have evaluated two such triage systems, the Simple Triage Scoring System 8 and the Ontario Health…”

“…Hence, this reflects a useful period for the study of triage tools, because we can see the effect of widespread severe influenza, while still being able to see what happens to patients who might have been excluded from critical care had the system been completely overwhelmed. Using the outcomes of admission to the intesive care unit and institution of mechanical ventilation, Morton and colleagues 7 demonstrate that P/F ratio is a good predictor. As gauged by comparisons of the area under the receiver operating characteristic curve of the scalar Simple Triage Scoring System measure or the sensitivity and specificity of the categorical OHPIP, P/F ratio outperforms both.…”

“…The OHPIP tools were developed by expert consensus and review of the literature, which indicated that the sequential organ failure assessment (SOFA) score was a good predictor of outcomes in the intesive care unit. 11 As Morton and colleagues 7 show, SOFA scores alone are less effective predictors of critical care admission and ventilation than the P/F ratio. The OHPIP also developed a reverse triage tool to aid decisions about discontinuation of therapy, and in what is the largest examination of this tool in patients with H1N1 influenza to date, this analysis suggests that it is poorly able to discriminate between patients who will survive and those who will not.…”