Effect of airway pressure display on interobserver agreement in the assessment of vascular pressures in patients with acute lung injury and acute respiratory distress syndrome

Crit Care Med. 2005 Jan;33(1):98-103; discussion 243-4. doi: 10.1097/01.ccm.0000150650.70142.e9.


Background: Previous investigations have identified significant interobserver variability in the measurements of central venous pressure and pulmonary artery occlusion pressure in critically ill patients. Large interobserver variability in the measurement of vascular pressures could potentially lead to inappropriate treatment decisions.

Objective: We postulated that adding an airway pressure signal (Paw) to pressure tracings of central venous pressure and pulmonary artery occlusion pressure would improve interobserver agreement by facilitating identification of end-expiration.

Design: To test this hypothesis, six independent experts used a standard protocol to interpret strip-chart recordings of central venous pressure and pulmonary artery occlusion pressure with or without Paw. Two observers were said to agree if their measurements were within 2 mm Hg of each other. SETTING/SUBJECTS/INTERVENTIONS: A total of 459 strip-chart recordings (303 without Paw and 156 with Paw) were obtained from 121 patients enrolled in the ARDSnet Fluids and Catheters Treatment Trial (FACTT) in 16 different hospitals.

Results: Agreement within 2 mm Hg between two measurements was 79% for central venous pressure strips without Paw vs. 86% with Paw. For pulmonary artery occlusion pressure, agreement increased from 71% without Paw to 83% with Paw. The increase in agreement with the addition of Paw was greater for strips demonstrating >8 mm Hg phasic respiratory variation compared with strips demonstrating less phasic respiratory variation.

Conclusion: Paw display is a simple, inexpensive method to facilitate the identification of end-expiration that can significantly improve interobserver agreement.

Publication types

  • Clinical Trial
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Airway Resistance / physiology*
  • Blood Pressure Determination / statistics & numerical data*
  • Central Venous Pressure / physiology*
  • Critical Care / methods*
  • Humans
  • Hydrostatic Pressure
  • Inservice Training
  • Lung Injury*
  • Monitoring, Physiologic / statistics & numerical data
  • Observer Variation*
  • Positive-Pressure Respiration / methods*
  • Pulmonary Wedge Pressure / physiology*
  • Quality Assurance, Health Care
  • Reproducibility of Results
  • Respiratory Distress Syndrome / physiopathology
  • Respiratory Distress Syndrome / therapy*
  • Signal Processing, Computer-Assisted
  • Transducers