Prone positioning unloads the right ventricle in severe ARDS

Chest. 2007 Nov;132(5):1440-6. doi: 10.1378/chest.07-1013. Epub 2007 Oct 9.

Abstract

Background: Despite airway pressure limitation, acute cor pulmonale persists in a minority of ARDS patients. Insufficient airway pressure limitation, hypercapnia, or both may be responsible. Because prone positioning (PP) has been shown to be a safe way to reduce airway pressure and to improve alveolar ventilation, we decided to assess its effect on right ventricular (RV) pressure overload in ARDS patients.

Methods: Between January 1998 and December 2006, we studied 42 ARDS patients treated by PP to correct severe oxygenation impairment (Pao2/fraction of inspired oxygen ratio, <100 mm Hg). RV function was evaluated by bedside transesophageal echocardiography, before and after 18 h of prone-position ventilation. RV enlargement was measured by RV/left ventricular (LV) end-diastolic area ratio in the long axis. Septal dyskinesia was quantified by measuring short-axis systolic eccentricity of the LV.

Results: Before PP, 21 patients (50%) had acute cor pulmonale, defined by RV enlargement associated with septal dyskinesia (group 1), whereas 21 patients had a normal RV (group 2). PP was accompanied by a significant decrease in airway pressure and Paco2. In group 1, this produced a significant decrease in mean (+/-SD) RV enlargement (from 0.91+/-0.22 to 0.61+/-0.21) after 18 h of PP (p=0.000) and a significant reduction in mean septal dyskinesia (from 1.5+/-0.2 to 1.1+/-0.1) after 18 h of PP (p=0.000).

Conclusion: In the most severe forms of ARDS, PP was an efficient means of controlling RV pressure overload.

MeSH terms

  • APACHE
  • Chi-Square Distribution
  • Echocardiography, Transesophageal
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prone Position / physiology*
  • Pulmonary Heart Disease / diagnostic imaging
  • Pulmonary Heart Disease / physiopathology*
  • Respiration, Artificial
  • Respiratory Distress Syndrome, Adult / physiopathology*
  • Respiratory Distress Syndrome, Adult / therapy
  • Statistics, Nonparametric
  • Ventricular Dysfunction, Right / diagnostic imaging
  • Ventricular Dysfunction, Right / physiopathology*