Impact of positive end-expiratory pressure on the definition of acute respiratory distress syndrome.

Abstract

OBJECTIVE:

We examined whether PEEP during the first hours of ARDS can induce such a change in oxygenation that could mask fulfillment of the AECC criteria of a PaO(2)/FIO(2) </= 200 essential for ARDS diagnosis.

DESIGN AND SETTING:

Observational, prospective cohort in two medical-surgical ICU in teaching hospitals.

PATIENTS:

48 consecutive patients who met AECC criteria of ARDS on 0 PEEP (ZEEP) at the moment of diagnosis.

MEASUREMENTS AND RESULTS:

PaO(2)/FIO(2) and lung mechanics were recorded on admission (0 h) to the ICU on ZEEP, and after 6, 12, and 24 h on PEEP levels selected by attending physicians. Lung Injury Score (LIS) was calculated at 0 and 24 h. PaO(2)/FIO(2) rose significantly from 121+/-45 on ZEEP at 0 h, to 234+/-85 on PEEP of 12.8+/-3.7 cmH(2)O after 24 h. LIS did not change significantly (2.34+/-0.53 vs. 2.42+/-0.62). These variables behaved similarly in pulmonary and extrapulmonary ARDS, and in survivors and nonsurvivors. After 24 h only 18 patients (38%) still had a PaO(2)/FIO(2) of 200 or lower. Their mortality was similar to that in the remaining patients (61% vs. 53%).

CONCLUSIONS:

The use of PEEP improved oxygenation such that one-half of patients after 6 h, and most after 24 h did not fulfill AECC hypoxemia criteria of ARDS. However, LIS remained stable in the overall series. These results suggest that PEEP level should be taken into consideration for ARDS diagnosis.

• Authors: Elisa Estenssoro, Arnaldo Dubin, Enrique Laffaire, Héctor S Canales, Gabriela Sáenz, Miriam Moseinco, Pierina Bachetti
• Journal: Intensive care medicine (Intensive Care Med) Vol. 29 Issue 11 Pg. 1936-42 (Nov 2003) ISSN: 0342-4642 [Print] United States
• PMID: 12955187 (Publication Type: Journal Article)

Chemical References

• Oxygen

Topics

• APACHE
• Aged
• Airway Resistance
• Analysis of Variance
• Blood Gas Analysis
• Discriminant Analysis
• Hospital Mortality
• Humans
• Lung Compliance
• Middle Aged
• Oxygen (blood)
• Positive-Pressure Respiration (methods)
• Prognosis
• Prospective Studies
• Pulmonary Gas Exchange
• Respiratory Distress Syndrome (diagnosis, etiology, mortality, therapy)
• Severity of Illness Index
• Survival Analysis
• Tidal Volume
• Time Factors
• Treatment Outcome