Lung volume recruitment maneuvers and respiratory system mechanics in mechanically ventilated mice

Respir Physiol Neurobiol. 2009 Dec 31;169(3):243-51. doi: 10.1016/j.resp.2009.09.012. Epub 2009 Sep 27.

Abstract

The study aim was to establish how recruitment maneuvers (RMs) influence lung mechanics and to determine whether RMs produce lung injury. Healthy BALB/c mice were allocated to receive positive end-expiratory pressure (PEEP) at 2 or 6 cmH(2)O and volume- (20 or 40 mL/kg) or pressure-controlled (25 cmH(2)O) RMs every 5 or 75 min for 150 min. The low-frequency forced oscillation technique was used to measure respiratory input impedance. Large RMs resulting in peak airway opening pressures (P(ao))>30 cmH(2)O did not increase inflammatory response or affect transcutaneous oxygen saturation but significantly lowered airway resistance, tissue damping and tissue elastance; the latter changes are likely associated with the bimodal pressure-volume behavior observed in mice. PEEP increase alone and application of RMs producing peak P(ao) below 25 cmH(2)O did not prevent or reverse changes in lung mechanics; whereas frequent application of substantial RMs on top of elevated PEEP levels produced stable lung mechanics without signs of lung injury.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Lung Injury / etiology
  • Acute Lung Injury / physiopathology
  • Airway Resistance / physiology*
  • Analysis of Variance
  • Animals
  • Bronchoalveolar Lavage Fluid
  • Cell Count / methods
  • Cytokines / metabolism
  • Disease Models, Animal
  • Female
  • Heart Rate / physiology
  • Lung / cytology
  • Lung / physiology*
  • Macrophages / metabolism
  • Macrophages / pathology
  • Mice
  • Mice, Inbred BALB C
  • Oxygen / metabolism
  • Positive-Pressure Respiration / methods
  • Respiration, Artificial*
  • Respiratory Mechanics / physiology*
  • Respiratory System*
  • Tidal Volume / physiology
  • Tracheostomy / methods

Substances

  • Cytokines
  • Oxygen