Chest
Volume 96, Issue 4, October 1989, Pages 849-851
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Clinical Investigations in Critical Care
An Early Test of Survival in Patients with the Adult Respiratory Distress Syndrome: The PaO2/FIo2 Ratio and its Differential Response to Conventional Therapy

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Patients with established adult respiratory distress syndrome (ARDS) have a mortality rate that exceeds 50 percent. We analyzed the magnitude of hypoxemia as manifest by the PaO2/FIo2 ratio and its early response to conventional therapy including positive end-expiratory pressure (PEEP) in the placebo group of a large multicenter study. The PaO2/FIo2 ratio was not different at the time of diagnosis of ARDS in those patients who lived compared to those who subsequently died. After one day of conventional therapy including PEEP, those patients who survived increased their PaO2/FIo2 ratio. The nonsurvivors did not improve over a seven-day course. The difference in the PaO2/FIo2 ratio was significant throughout the seven-day observation period. We conclude that the early response to conventional therapy picks a patient population with a good prognosis and can be used as a test of likely survival from ARDS.

Section snippets

Study Design

The study design has been reported previously.13 The present study is a retrospective analysis of patients with respiratory failure from a two-step prospective multicenter study designed to determine the effect of PGE, on ARDS. The results of the second step of the study have been reported.13 Both studies were identical in goals, except the first step of the study included 50 patients and accepted patients with multiorgan failure into the trial. When interim analysis revealed no differences in

Demographics

Thirteen centers enrolled 150 patients; 74 patients were randomized to receive placebo. Only the placebo patients are reported in this study. Demographics and selected physiologic variables of the patients are shown in Table 2. Thirty-seven patients survived and 37 patients died for a mortality rate of 50 percent.

Chest X-ray Examination

Results of all chest x-ray films were abnormal at baseline.

Indices of Oxygenation

Figure 1 shows the PaO2/FIo2 by survival for seven days. Table 3 shows the PaO2/FIo2 ratio and their level of significance

DISCUSSION

All patients in this study had ARDS that occurred from trauma, postoperatively, or from sepsis. They had diffuse infiltrates on the chest roentgenogram and had a pulmonary artery wedge pressure (PAWP) ≤18 mm Hg. They were mechanically ventilated and had a resultant partial pressure of oxygen in arterial blood: fractional concentration of oxygen in inspired air (PaO2/FIo2) ratio less than or equal to 150 with no PEEP or less than 200 with PEEP. In this study, we anayzed only placebo patients to

REFERENCES (13)

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Cited by (142)

  • PaO<inf>2</inf>/FiO<inf>2</inf> Deterioration During Stable Extracorporeal Membrane Oxygenation Associates With Protracted Recovery and Increased Mortality in Severe Acute Respiratory Distress Syndrome

    2016, Annals of Thoracic Surgery
    Citation Excerpt :

    PF ratio variation within the first week of ARDS diagnosis was also found to have prognostic significance in patients treated without ECMO. Bone and colleagues [19] analyzed PF ratio and its early response to conventional therapy in the placebo group of a large multicenter study. PF ratio was not different at the time of diagnosis of ARDS in survivors compared with nonsurvivors.

  • Clinical characteristics and outcomes are similar in ARDS diagnosed by oxygen saturation/F io 2 ratio compared with Pa o 2/F io 2 Ratio

    2015, Chest
    Citation Excerpt :

    Using this approach, we found no association between the severity of ARDS diagnosed by PF ratios and hospital mortality. These findings are concordant with several studies that have shown that the PF ratio measured at the onset of ARDS is not an independent predictor of mortality.20–25 One possible explanation for the lack of the power of the PF ratio to discriminate adverse outcome in ARDS is that the PF ratio is highly variable depending on the ventilator strategy chosen.

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Manuscript received July 14; revision accepted August 3.

*

The Prostaglandin E, Study Group consisted of: Bush-Presbyterian-St. Lukes Medical Center, Chicago: Bone RC, Balk R, Szidon P, Hanley M, Jacobs E; Division of Pulmonary Medicine, Maine Medical Center, Portland, ME: Caldwell E, Altaian F, Bagwell S, Cox P, Lambert R, Williams W; University of Minnesota Hospital, Minneapolis: Cerra F, Berlauk J, Gilmour I; Ohio State University, Columbus: Cloutier C, Davies E, Steinburg S; Winthrop University Hospital, Mineola, NY: Fein A, Grant M, Montavani R, Neiderman M, Sklarek H; University of Texas Health Sciences Center, San Antonio, TX: Gaskill H, Levine B; Division of Pulmonary and Critical Care Medicine, Harborview Medical Center, Seattle: Hudson L, Maunder RJ; St. Louis University School of Medicine, Pulmonary Division, St. Louis: Hyers T, Dettenmeier P; Tulane University Medical Center, New Orleans: Kerstein M, Moulder P, Webb W; University of Maryland Hospital, Pulmonary Division, Baltimore: Silverman H, Belzberg H, Mendoza J; Rhode Island Hospital, Department of Surgery, Providence: Slotman G, Burchard K; Geisinger Medical Center, Danville, PA: Smith J, Blackburn J, Burns R; Department of Surgery, University of Texas HSC-Dallas, Dallas: Weigelt J; Coordinating Center, The Upjohn Company, Kalamazoo, MI: Ursprung JJ, Maile M, Wilks NE, Drennen K.

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