The aims of this study included assessment of accuracy of respiratory inductive plethysmography when pulmonary hyperinflation was induced by application of PEEP, and examination of breathing petterns of normal subjects, intubated patients required mechanical ventilation and intubated patients immediately before extubation during application of PEEP by demand valve and high gas flow reservoir bag systems. Validation of tidal volume (V(T)) and end-expiratory level measured with respiratory inductive plethysmography to simultaneous spirometry (SP) was achieved with PEEP levels up to 12.5 cm H2O in 7 normals. In 17 intubated patients, almost all V(T) values measured with respiratory inductive plethysmography fell within ±10% of SP even with 2 to 3 changes of body posture. In normal subjects, increasing levels of PEEP from the demand valve system produced nonprogressive rises of V(T) and mean inspiratory flow, falls of frequency and fractional inspiratory time (T(I)/T(TOT)), and no changes of minute ventilation (V̇(min)), nor mean expiratory flow. PEEP from the high gas flow reservoir bag system produced nonprogressive rises of V(T) and rib cage (RC) contribution oto V(T), and rises of V̇(min) and mean inspiratory and expiratory flows between 10.0 and 12.5 cm H2O of PEEP. Intubated patients requiring intermittent mandatory ventilation (IMV) had a rapid, shallow breathing pattern unaltered by PEEP levels delivered by either system up to 12.5 cm H2O despite increases of end-expiratory level. Intubated patients who were about to be extubated breathed with patterns closer to ambulatory normal subjects with the exception of their elevated RC contribution to V(T). In these patients, changes in breathing pattern produced by 10.0 cm H2O of PEEP using randomized application of both delivery systems were similar to those of normal subjects. Our study indicates that noninvasive monitoring can be confidently utilized to assess breathing patterns of critically ill patients.
|Number of pages||9|
|Journal||Critical Care Medicine|
|State||Published - Dec 1 1983|
ASJC Scopus subject areas
- Critical Care and Intensive Care Medicine