Assessment of the single-occlusion technique for measurements of respiratory mechanics and respiratory drive in healthy term neonates using a commercially available computerized pulmonary function testing system.

In this study, a critical assessment of the single-occlusion technique as a means of measuring passive respiratory mechanics and respiratory drive (P0.1) was performed in nonintubated spontaneously breathing healthy term neonates using commercially available computerized equipment (PEDS system). In general, we found that quality parameters only partially conformed to the international established standards for measuring passive respiratory mechanics. There was a failure rate of technically acceptable occlusions of about 50% for respiratory mechanics measurements and 20% for P0.1 measurements. Intersubject variability of the data was between 10 and 40%. After studying different lengths of occlusion times (Tocc; 0.2, 0.3, 0.4 and 0.5 s), it was found that acceptable occlusions for passive respiratory mechanics were obtained only if the expiratory Tocc exceeded 0.2 s. Increasing the Tocc had no effect on the absolute values of respiratory mechanics but showed a significant trend towards more technically acceptable occlusions. We speculate that a Tocc of at least 0.4 s may be a prerequisite for obtaining reliable results for respiratory mechanics in healthy term neonates. Copyright 2003 S. Karger AG, Basel