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Airway closure in anesthetized infants and children: influence of inspiratory pressures and volumes

Thorsteinsson, Adalbjörn LU ; Werner, Olof LU ; Jonmarker, Christer LU and Larsson, A (2002) In Acta Anaesthesiologica Scandinavica 46(5). p.529-536
Abstract
Background: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. Methods: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF6) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6-13years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH(2)O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to... (More)
Background: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. Methods: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF6) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6-13years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH(2)O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to -20 cmH(2)O. (CC/EEV >1 indicates that airway closure might occur during tidal breathing). Furthermore, a measure of uneven ventilation, multiple breath alveolar mixing efficiency (MBAME), was obtained. Results: Airway closure within the tidal volume (CC/EEV>1) was observed in four and eight children (not significant, NS) after 20 and 30cmH(2)O inflation, respectively. However, CC30/EEV was>CC20/EEV in all children (Pless than or equal to0.001). The MBAME was 75+/-7% (normal) and did not correlate with CC/EEV. Conclusion: Airway closure within tidal volumes may occur in artificially ventilated healthy children during ventilation with low inspiratory pressure. However, the risk of airway closure and thus opening within the tidal volume increases when the inspiratory pressures are increased. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
multibreath, pediatric, anesthesia, airway closure, sulfur hexafluoride, functional residual capacity, washout
in
Acta Anaesthesiologica Scandinavica
volume
46
issue
5
pages
529 - 536
publisher
Wiley-Blackwell
external identifiers
  • wos:000175838900010
  • pmid:12027847
  • scopus:0036100189
ISSN
0001-5172
DOI
10.1034/j.1399-6576.2002.460510.x
language
English
LU publication?
yes
id
61d36f39-ee2f-4b82-89b5-ea8341b9af40 (old id 337358)
date added to LUP
2007-11-09 14:14:52
date last changed
2017-01-01 05:08:44
@article{61d36f39-ee2f-4b82-89b5-ea8341b9af40,
  abstract     = {Background: Cyclic opening and closing of lung units during tidal breathing may be an important cause of iatrogenic lung injury. We hypothesized that airway closure is uncommon in children with healthy lungs when inspiratory pressures are kept low, but paradoxically may occur when inspiratory pressures are increased. Methods: Elastic equilibrium volume (EEV) and closing capacity (CC) were measured with a tracer gas (SF6) technique in 11 anesthetized, muscle-relaxed, endotracheally intubated and artificially ventilated healthy children, aged 0.6-13years. Airway closing was studied in a randomized order at two inflation pressures, +20 or +30 cmH(2)O, and CC and CC/EEV were calculated from the plots obtained when the lungs were exsufflated to -20 cmH(2)O. (CC/EEV >1 indicates that airway closure might occur during tidal breathing). Furthermore, a measure of uneven ventilation, multiple breath alveolar mixing efficiency (MBAME), was obtained. Results: Airway closure within the tidal volume (CC/EEV>1) was observed in four and eight children (not significant, NS) after 20 and 30cmH(2)O inflation, respectively. However, CC30/EEV was>CC20/EEV in all children (Pless than or equal to0.001). The MBAME was 75+/-7% (normal) and did not correlate with CC/EEV. Conclusion: Airway closure within tidal volumes may occur in artificially ventilated healthy children during ventilation with low inspiratory pressure. However, the risk of airway closure and thus opening within the tidal volume increases when the inspiratory pressures are increased.},
  author       = {Thorsteinsson, Adalbjörn and Werner, Olof and Jonmarker, Christer and Larsson, A},
  issn         = {0001-5172},
  keyword      = {multibreath,pediatric,anesthesia,airway closure,sulfur hexafluoride,functional residual capacity,washout},
  language     = {eng},
  number       = {5},
  pages        = {529--536},
  publisher    = {Wiley-Blackwell},
  series       = {Acta Anaesthesiologica Scandinavica},
  title        = {Airway closure in anesthetized infants and children: influence of inspiratory pressures and volumes},
  url          = {http://dx.doi.org/10.1034/j.1399-6576.2002.460510.x},
  volume       = {46},
  year         = {2002},
}