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Dynamic elastic pressure-volume loops in healthy pigs recorded with inspiratory and expiratory sinusoidal flow modulationRelationship to static pressure-volume loops.

Bitzén, Ulrika LU ; Drefeldt, Björn LU ; Niklason, Lisbet LU and Jonson, Björn LU (2004) In Intensive Care Medicine 30(3). p.481-488
Abstract
Objective: The objective was to analyse relationships between inspiratory and expiratory static and dynamic elastic pressure-volume (P-el/V) curves in healthy pigs. Design: The modulated low flow method was developed to allow studies also of the expiratory P-el/V curves. Static P-el/V (P-el,P-st/V) and dynamic P-el/V (P-el,P-dyn/V) loops were studied in healthy pigs. Setting: Animal research laboratory in a university hospital. Material: Ten healthy anaesthetised and paralysed pigs. Interventions and measurements: A computer controlled a Servo Ventilator 900C with respect to respiratory rate, inspiratory flow and expiratory pressure to achieve a sinusoidal modulation of inspiration and expiration for determination of P-el,P-dyn/V loops... (More)
Objective: The objective was to analyse relationships between inspiratory and expiratory static and dynamic elastic pressure-volume (P-el/V) curves in healthy pigs. Design: The modulated low flow method was developed to allow studies also of the expiratory P-el/V curves. Static P-el/V (P-el,P-st/V) and dynamic P-el/V (P-el,P-dyn/V) loops were studied in healthy pigs. Setting: Animal research laboratory in a university hospital. Material: Ten healthy anaesthetised and paralysed pigs. Interventions and measurements: A computer controlled a Servo Ventilator 900C with respect to respiratory rate, inspiratory flow and expiratory pressure to achieve a sinusoidal modulation of inspiration and expiration for determination of P-el,P-dyn/V loops from zero end-expiratory pressure (ZEEP) and from a positive end-expiratory pressure (PEEP) of 6 cmH(2)O to 20, 35 and 50 cmH(2)O. The same system was used for studies of P-el,P-st/V loops with the flow-interruption method from ZEEP and PEEP to 35 cmH(2)O. Recordings were analysed with an iterative technique. Results: The feasibility of automated determination of P-el,P-dyn/V loops was demonstrated. Differences between P-el,P-dyn/V and P-el,P-st/V loops were explained by viscoelastic behaviour. P-el,P-st/V loops recorded from PEEP to 35 cmH(2)O showed no significant hysteresis, indicating a non-significant surface tension hysteresis. P-el,P-dyn/V loops from PEEP and both P-el,P-st/V and P-el,P-dyn/V loops from ZEEP to 35 cmH(2)O showed hysteresis. This indicates that lung collapse/re-expansion caused P-el/V loop hysteresis which, in P-el,P-dyn/V loops, was augmented by viscoelastic behaviour. Conclusions: Viscoelasticity influences P-el,P-dyn/V curves. Hysteresis caused by surface tension merits re-evaluation. Lung collapse and re-expansion may be indicated by hysteresis of P-el/V loops. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
mechanical, respiratory mechanics, hysteresis, compliance, ventilation, swine
in
Intensive Care Medicine
volume
30
issue
3
pages
481 - 488
publisher
Springer
external identifiers
  • wos:000189364300021
  • pmid:14963643
  • scopus:1642329179
ISSN
0342-4642
DOI
10.1007/s00134-003-2156-6
language
English
LU publication?
yes
id
8b34dd04-e16a-422e-926c-b23a14a4247a (old id 120534)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14963643&dopt=Abstract
date added to LUP
2007-07-17 13:33:35
date last changed
2017-01-01 04:30:45
@article{8b34dd04-e16a-422e-926c-b23a14a4247a,
  abstract     = {Objective: The objective was to analyse relationships between inspiratory and expiratory static and dynamic elastic pressure-volume (P-el/V) curves in healthy pigs. Design: The modulated low flow method was developed to allow studies also of the expiratory P-el/V curves. Static P-el/V (P-el,P-st/V) and dynamic P-el/V (P-el,P-dyn/V) loops were studied in healthy pigs. Setting: Animal research laboratory in a university hospital. Material: Ten healthy anaesthetised and paralysed pigs. Interventions and measurements: A computer controlled a Servo Ventilator 900C with respect to respiratory rate, inspiratory flow and expiratory pressure to achieve a sinusoidal modulation of inspiration and expiration for determination of P-el,P-dyn/V loops from zero end-expiratory pressure (ZEEP) and from a positive end-expiratory pressure (PEEP) of 6 cmH(2)O to 20, 35 and 50 cmH(2)O. The same system was used for studies of P-el,P-st/V loops with the flow-interruption method from ZEEP and PEEP to 35 cmH(2)O. Recordings were analysed with an iterative technique. Results: The feasibility of automated determination of P-el,P-dyn/V loops was demonstrated. Differences between P-el,P-dyn/V and P-el,P-st/V loops were explained by viscoelastic behaviour. P-el,P-st/V loops recorded from PEEP to 35 cmH(2)O showed no significant hysteresis, indicating a non-significant surface tension hysteresis. P-el,P-dyn/V loops from PEEP and both P-el,P-st/V and P-el,P-dyn/V loops from ZEEP to 35 cmH(2)O showed hysteresis. This indicates that lung collapse/re-expansion caused P-el/V loop hysteresis which, in P-el,P-dyn/V loops, was augmented by viscoelastic behaviour. Conclusions: Viscoelasticity influences P-el,P-dyn/V curves. Hysteresis caused by surface tension merits re-evaluation. Lung collapse and re-expansion may be indicated by hysteresis of P-el/V loops.},
  author       = {Bitzén, Ulrika and Drefeldt, Björn and Niklason, Lisbet and Jonson, Björn},
  issn         = {0342-4642},
  keyword      = {mechanical,respiratory mechanics,hysteresis,compliance,ventilation,swine},
  language     = {eng},
  number       = {3},
  pages        = {481--488},
  publisher    = {Springer},
  series       = {Intensive Care Medicine},
  title        = {Dynamic elastic pressure-volume loops in healthy pigs recorded with inspiratory and expiratory sinusoidal flow modulationRelationship to static pressure-volume loops.},
  url          = {http://dx.doi.org/10.1007/s00134-003-2156-6},
  volume       = {30},
  year         = {2004},
}