Elevated static compliance of the total respiratory system: early predictor of weaning unsuccess in severed COPD patients mechanically ventilated

Intensive Care Med. 1995 May;21(5):399-405. doi: 10.1007/BF01707408.


Objective: To assess in a group of COPD patients mechanically ventilated for an episode of acute respiratory failure the respiratory mechanics with a simple and non invasive method at the bedside in order to evaluate if these parameters may be predictive of weaning failure or success.

Design: A prospective study.

Setting: Intensive care and intermediate intensive care units.

Patients: 23 COPD patients ventilated for acute respiratory failure and studied within 24 hours from intubation.

Methods: Using end-expiratory and end-inspiratory airway occlusion technique, we measured PEEPi, static compliance of the respiratory system (Crs, st) maximum respiratory resistance (Rrsmax) and minimum respiratory resistance (Rrsmin).

Measurements and results: The weaned group (A) and the not weaned group (B) were not different regarding to static PEEPi (group A 8.5 +/- 4.0 vs group B 8.9 +/- 2.6 cmH2O), TO Rrsmax (22.4 +/- 5.3 versus 22.2 +/- 9.0 cmH2O/1/s) and to Rrsmin (17.6 +/- 5.5 versus 17.9 +/- 8.0 cmH2O/1/s), while a significant difference (p < 0.001) has been found in Cst, rs (62.7 +/- 17.% versus 111.6 +/- 18.0 ml/cm H2O). The threshold value of 88.5 ml/cmH2O was identified by discriminant analysis and provided the best separation between the two groups, with a sensitivity of 0.85 and a specificity of 0.87.

Conclusion: Cst, rs measured non invasively in the first 24 h from intubation, provided a good separation between the patients who were successfully weaned and those who failed.

MeSH terms

  • Acute Disease
  • Aged
  • Airway Resistance
  • Discriminant Analysis
  • Female
  • Humans
  • Lung Compliance*
  • Lung Diseases, Obstructive / complications*
  • Male
  • Middle Aged
  • Positive-Pressure Respiration, Intrinsic / diagnosis
  • Predictive Value of Tests
  • Prospective Studies
  • Respiratory Insufficiency / etiology
  • Respiratory Insufficiency / physiopathology
  • Respiratory Insufficiency / therapy*
  • Treatment Failure
  • Ventilator Weaning*