One-lung ventilation induces hyperperfusion and alveolar damage in the ventilated lung: an experimental study

Br J Anaesth. 2008 Apr;100(4):549-59. doi: 10.1093/bja/aen021. Epub 2008 Feb 27.

Abstract

Background: One-lung ventilation (OLV) increases mechanical stress in the lung and affects ventilation and perfusion (V, Q). There are no data on the effects of OLV on postoperative V/Q matching. Thus, this controlled study evaluates the influence of OLV on V/Q distribution in a pig model using a gamma camera technique [single-photon emission computed tomography (SPECT)] and relates these findings to lung histopathology after OLV.

Methods: Eleven anaesthetized and ventilated pigs (V(T)=10 ml kg(-1), Fio2=0.40, PEEP=5 cm H2O) were studied. After lung separation, OLV and thoracotomy were performed in seven pigs (OLV group). During OLV and in a two-lung ventilation (TLV), control group (n=4) ventilation settings remained unchanged. SPECT with (81m)Kr (ventilation) and (99m)Tc-labelled macro-aggregated albumin (perfusion) was performed before, during, and 90 min after OLV/TLV. Finally, lung tissue samples were harvested and examined for alveolar damage.

Results: OLV affected ventilation and haemodynamic variables, but there were no differences between the OLV group and the control group before and after OLV/TLV. SPECT revealed an increase of perfusion in the dependent lung compared with baseline (49-56%), and a corresponding reduction of perfusion (51-44%) in non-dependent lungs after OLV. No perfusion changes were observed in the control group. This resulted in increased low V/Q regions and a shift of V/Q areas to 0.3-0.5 (10(-0.5)-10(-0.3)) in dependent lungs of OLV pigs and was associated with an increased diffuse alveolar damage score.

Conclusions: OLV in pigs results in a substantial V/Q mismatch, hyperperfusion, and alveolar damage in the dependent lung and may thus contribute to gas exchange impairment after thoracic surgery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbon Dioxide / blood
  • Hemodynamics
  • Lung / diagnostic imaging
  • Lung / physiopathology
  • Lung Diseases / diagnostic imaging
  • Lung Diseases / etiology*
  • Lung Diseases / pathology
  • Lung Diseases / physiopathology
  • Oxygen / blood
  • Partial Pressure
  • Pulmonary Alveoli / pathology*
  • Pulmonary Gas Exchange
  • Respiration, Artificial / adverse effects*
  • Respiration, Artificial / methods
  • Sus scrofa
  • Thoracotomy
  • Tomography, Emission-Computed, Single-Photon / methods
  • Ventilation-Perfusion Ratio*

Substances

  • Carbon Dioxide
  • Oxygen