Effect of median sternotomy on respiratory system compliance in humans: Evaluation without sophisticated instrumentation

Abstract

To evaluate the effect of median sternotomy on the static compliance of the respiratory system (CRS) in humans, we used a new technique for pressure-volume (PV) curve tracing without sophisticated instrumentation. The accuracy and the reproducibility of the new technique were tested in a lung simulator, while its agreement with multiple-occlusion (MO) technique (the technique most often used in the ICU for CRS measurement) was evaluated in 12 mechanically ventilated patients. Finally, the NCI technique was used in 13 cardiosurgical patients to measure CRS before and after median sternotomy. Measurements provided by the NCI technique were at least as accurate as standard measurements in the bench study. In ICU patients, we observed a good agreement of CRS measurements provided by the two techniques (bias 0.8, 95% limits of agreement -5.6 to 7.2 mlycm H2O) and a similar reproducibility. In cardiosurgical patients we observed a significant (P=0.037) increase in CRS with an upward and leftward shift of the PV-curve after median sternotomy. No adverse effect was observed during PV-curve tracing maneuvers. The simplicity of NCI technique allowed for the first time, to our knowledge, PV-curve tracing in humans during cardiosurgery and revealed 5% increase in CRS immediately after median sternotomy. © 2009 Published by European Association for Cardio-Thoracic Surgery. All rights reserved.