Bedside Ultrasound Assessment of Positive End-Expiratory Pressure-Induced Lung Recruitment

Am J Respir Crit Care Med. 2011 Feb 1;183(3):341-7. doi: 10.1164/rccm.201003-0369OC. Epub 2010 Sep 17.

Abstract

Rationale: In the critically ill patients, lung ultrasound (LUS) is increasingly being used at the bedside for assessing alveolar-interstitial syndrome, lung consolidation, pneumonia, pneumothorax, and pleural effusion. It could be an easily repeatable noninvasive tool for assessing lung recruitment.

Objectives: Our goal was to compare the pressure-volume (PV) curve method with LUS for assessing positive end-expiratory pressure (PEEP)-induced lung recruitment in patients with acute respiratory distress syndrome/acute lung injury (ARDS/ALI).

Methods: Thirty patients with ARDS and 10 patients with ALI were prospectively studied. PV curves and LUS were performed in PEEP 0 and PEEP 15 cm H₂O₂. PEEP-induced lung recruitment was measured using the PV curve method.

Measurements and main results: Four LUS entities were defined: consolidation; multiple, irregularly spaced B lines; multiple coalescent B lines; and normal aeration. For each of the 12 lung regions examined, PEEP-induced ultrasound changes were measured, and an ultrasound reaeration score was calculated. A highly significant correlation was found between PEEP-induced lung recruitment measured by PV curves and ultrasound reaeration score (Rho = 0.88; P < 0.0001). An ultrasound reaeration score of +8 or higher was associated with a PEEP-induced lung recruitment greater than 600 ml. An ultrasound lung reaeration score of +4 or less was associated with a PEEP-induced lung recruitment ranging from 75 to 450 ml. A statistically significant correlation was found between LUS reaeration score and PEEP-induced increase in Pa(O₂) (Rho = 0.63; P < 0.05).

Conclusions: PEEP-induced lung recruitment can be adequately estimated with bedside LUS. Because LUS cannot assess PEEP-induced lung hyperinflation, it should not be the sole method for PEEP titration.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Acute Lung Injury / diagnostic imaging*
  • Acute Lung Injury / physiopathology
  • Acute Lung Injury / therapy
  • Humans
  • Lung / diagnostic imaging*
  • Lung / physiology
  • Middle Aged
  • Point-of-Care Systems*
  • Positive-Pressure Respiration*
  • Respiratory Distress Syndrome, Adult / diagnostic imaging*
  • Respiratory Distress Syndrome, Adult / physiopathology
  • Respiratory Distress Syndrome, Adult / therapy
  • Respiratory Function Tests
  • Tomography, X-Ray Computed
  • Treatment Outcome
  • Ultrasonography