Determination of respiratory system mechanics during inspiration and expiration by FLow-controlled EXpiration (FLEX): a pilot study in anesthetized pigs
2014 (English)In: Minerva Anestesiologica, ISSN 0375-9393, Vol. 80, no 1, 19-28 p.Article in journal (Refereed) Published
Background. Differences between inspiratory and expiratory lung mechanics result in the hysteresis of the pressure volume-loop. While hysteresis area is a global parameter describing the difference between inspiration and expiration in mechanics under quasi-static conditions, a detailed analysis of this difference under the dynamic conditions of mechanical ventilation is feasible once inspiratory and expiratory compliance (C-in/C-ex) are determined separately. This requires uncoupling of expiratory flow rate and volume (V). Methods. Five piglets were mechanically ventilated at positive end-expiratory pressure (PEEP) levels ranging from 0 to 15 cmH(2)O. Expiratory flow rate was linearized by a computer-controlled resistor (flow-controlled expiration). The volume-dependent C-in(V) and C-ex(V) profiles were calculated from the tracheal pressure volume-loops. Results. The intratidal curve-progression of C-ex(V) was altogether higher with a steeper slope compared to C-in(V). With increasing positive end-expiratory pressure (PEEP) dynamic hysteresis area decreased and C-ex(V) tended to run more parallel to C-in(V), Conclusion. The relation between inspiratory and expiratory compliance profiles is associated with the hysteresis area and behaves PEEP dependent. Analysing the C-in-C-ex-relation might therefore potentially offer a new approach to titrate PEEP and tidal volume.
Place, publisher, year, edition, pages
2014. Vol. 80, no 1, 19-28 p.
Compliance, Respiratory system, Peak expiratory flow rate, Respiratory mechanics
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-221724ISI: 000332140600006OAI: oai:DiVA.org:uu-221724DiVA: diva2:710188