Abstract
Purpose
To determine whether, during mechanical ventilation, an optimal positive end-expiratory pressure (PEEP) can be identified
by measurement of regional tidal volume and compliance [V
T(reg), C
RS(reg)].
by measurement of regional tidal volume and compliance [V
T(reg), C
RS(reg)].
Methods
Sixteen anaesthetized intubated neonatal piglets underwent a stepwise vital capacity manoeuvre performed during pressure control
ventilation, with 5 cmH2O PEEP increments to 25 cmH2O, and decrements to 0 cmH2O. Peak inflating pressure was 10 cmH2O above PEEP throughout. The manoeuvre was performed in the normal lung, after repeated saline lavage and after surfactant
therapy. Global V
T and C
RS were measured at the airway opening; V
T(reg) and C
RS(reg) were measured in the ventral, medial and dorsal lung using electrical impedance tomography (EIT).
ventilation, with 5 cmH2O PEEP increments to 25 cmH2O, and decrements to 0 cmH2O. Peak inflating pressure was 10 cmH2O above PEEP throughout. The manoeuvre was performed in the normal lung, after repeated saline lavage and after surfactant
therapy. Global V
T and C
RS were measured at the airway opening; V
T(reg) and C
RS(reg) were measured in the ventral, medial and dorsal lung using electrical impedance tomography (EIT).
Results
Most uniform distribution of regional tidal ventilation was noted during PEEP decrements after lung recruitment, at varying
PEEP levels. In the lavaged and surfactant-treated lung the PEEP optimal for ventilation distribution was also associated
with highest mean V
T(reg) [lavaged: 95 ± 9.3% of maximum, mean ± standard deviation (SD); surfactant-treated: 92 ± 17%] and global V
T (96 ± 10%; 96 ± 15%). Regional C
RS plots clearly demonstrated co-existent ventral overdistension and dorsal recruitment, particularly during PEEP increments;
whereas during PEEP decrements, peak C
RS(reg) values showed considerable interregional concordance [e.g. peak C
RS(reg) in the lavaged left lung; ventral: 0.017 ± 0.0036; medial: 0.016 ± 0.0054; dorsal: 0.017 ± 0.0073 cmH2O?1; P = 0.98, analysis of variance (ANOVA)].
PEEP levels. In the lavaged and surfactant-treated lung the PEEP optimal for ventilation distribution was also associated
with highest mean V
T(reg) [lavaged: 95 ± 9.3% of maximum, mean ± standard deviation (SD); surfactant-treated: 92 ± 17%] and global V
T (96 ± 10%; 96 ± 15%). Regional C
RS plots clearly demonstrated co-existent ventral overdistension and dorsal recruitment, particularly during PEEP increments;
whereas during PEEP decrements, peak C
RS(reg) values showed considerable interregional concordance [e.g. peak C
RS(reg) in the lavaged left lung; ventral: 0.017 ± 0.0036; medial: 0.016 ± 0.0054; dorsal: 0.017 ± 0.0073 cmH2O?1; P = 0.98, analysis of variance (ANOVA)].
Conclusions
After lung recruitment, a PEEP level can be identified by EIT at which tidal ventilation is uniformly distributed, with associated
concordance in compliance between lung regions. Bedside monitoring of regional tidal ventilation and compliance using EIT
may thus aid in PEEP selection.
concordance in compliance between lung regions. Bedside monitoring of regional tidal ventilation and compliance using EIT
may thus aid in PEEP selection.
- Content Type Journal Article
- DOI 10.1007/s00134-010-1995-1
- Authors
- Peter A. Dargaville, Department of Paediatrics, Royal Hobart Hospital and University of Tasmania, Liverpool Street, Hobart, TAS 7000, Australia
- Peter C. Rimensberger, Pediatric and Neonatal Intensive Care Unit, Children's Hospital, University of Geneva, Geneva, Switzerland
- Inez Frerichs, Department of Anaesthesiology and Intensive Care Medicine, University Medical Centre Schleswig-Holstein, Campus Kiel, Kiel, Germany
- Journal Intensive Care Medicine
- Online ISSN 1432-1238
- Print ISSN 0342-4642
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