Respiratory System Mechanics or Pulmonary Mechanics in the Prone Position

In Response: We agree with Dr. Drummond that our measurement of compliance probably more closely represents compliance of the entire respiratory system, rather than true pulmonary compliance. However, others [1] have recently demonstrated that the change in respiratory system compliance that occurs in obese patients during general anesthesia is closely correlated with a change in pulmonary compliance, but not chest wall compliance. We hope that our future studies will help to differentiate the effect of obesity and frame type on the individual components of respiratory system compliance. Jeffrey Kirsch Department of Anesthesiology and Critical Care Medicine; Johns Hopkins University; School of Medicine; Baltimore, MD 21287-7834