Ventilatory Ratio Is a Valuable Prognostic Indicator in an Observational Cohort of Patients With ARDS

Emily R Siegel; Hanjing Zhuo; Pratik Sinha; Alexander I Papolos; Siyuan A Ni; Kathryn Vessel; Annika Belzer; Emily B Minus; Carolyn S Calfee; Michael A Matthay; Katherine D Wick

doi:10.4187/respcare.09854

Ventilatory Ratio Is a Valuable Prognostic Indicator in an Observational Cohort of Patients With ARDS

Respir Care. 2022 Sep;67(9):1075-1081. doi: 10.4187/respcare.09854. Epub 2022 May 31.

Authors

Affiliations

¹ School of Medicine, University of California, San Francisco, San Francisco, California.
² Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California.
³ Department of Anesthesiology, Washington University in St. Louis, St. Louis, Missouri.
⁴ Departments of Cardiology and Critical Care, MedStar Washington Hospital Center, Washington, District of Columbia.
⁵ Department of Pulmonology, Mills-Peninsula Medical Center, Burlingame, California.
⁶ Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California; Department of Medicine, Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, University of California, San Francisco, San Francisco, California; and Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California.
⁷ Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California. Katherine.wick@ucsf.edu.

Abstract

Background: How indices specific to respiratory compromise contribute to prognostication in patients with ARDS is not well characterized in general clinical populations. The primary objective of this study was to identify variables specific to respiratory failure that might add prognostic value to indicators of systemic illness severity in an observational cohort of subjects with ARDS.

Methods: Fifty subjects with ARDS were enrolled in a single-center, prospective, observational cohort. We tested the contribution of respiratory variables (oxygenation index, ventilatory ratio [VR], and the radiographic assessment of lung edema score) to logistic regression models of 28-d mortality adjusted for indicators of systemic illness severity (the Acute Physiology and Chronic Health Evaluation [APACHE] III score or severity of shock as measured by the number of vasopressors required at baseline) using likelihood ratio testing. We also compared a model utilizing APACHE III with one including baseline number of vasopressors by comparing the area under the receiver operating curve (AUROC).

Results: VR significantly improved model performance by likelihood ratio testing when added to APACHE III (P = .036) or the number of vasopressors at baseline (P = .01). Number of vasopressors required at baseline had similar prognostic discrimination to the APACHE III. A model including the number of vasopressors and VR (AUROC 0.77 [95% CI 0.64-0.90]) was comparable to a model including APACHE III and VR (AUROC 0.81 [95% CI 0.68-0.93]; P for comparison = .58.).

Conclusions: In this observational cohort of subjects with ARDS, the VR significantly improved discrimination for mortality when combined with indicators of severe systemic illness. The number of vasopressors required at baseline and APACHE III had similar discrimination for mortality when combined with VR. VR is easily obtained at the bedside and offers promise for clinical prognostication.

Keywords: ARDS; pulmonary dead space; pulmonary edema; ventilatory ratio.

Publication types

Observational Study

MeSH terms

APACHE
Cohort Studies
Humans
Intensive Care Units
Prognosis
Prospective Studies
ROC Curve
Respiratory Distress Syndrome*

Abstract

Publication types

MeSH terms

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