Respiratory compliance assessed from chest expansion and inflation pressure in ventilated neonates

We evaluated a bedside method of assessing respiratory compliance from chest expansion, which is judged by eye and classified into three tidal volume categories, and from the inflation pressure read on the respirator's manometer. Compliance assessed by this method was compared with the compliance measured by the injection technique in 45 randomly chosen newborns ventilated for various diseases. The compliance assessed from chest expansion and inflation pressure correlated significantly with the measured compliance (r = 0.86, p < 0.001). Interobserver reliability was acceptable for clinical practice and improved within 6 months of training (weighted kappa = 0.67 versus 0.86). Within ten individuals, changes of compliance assessed by this method were also significantly correlated with those of measured compliance (r = 0.85, p < 0.01). This method, termed "optical compliance," is instantaneously and always available for all patients on ventilators without any additional apparatus and thus might improve the assessment of respiratory function in routine care and emergency situations.