Lung volume assessments in normal and surfactant depleted lungs: agreement between bedside techniques and CT imaging.
- Albu G Pathophysiological Experimental Platform, Department of Anaesthesiology, Pharmacology and Intensive Care, University of Geneva, 1 Rue Michel Servet, CH-1205 Geneva, Switzerland.
- Petak F Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, H-6720 Szeged, Hungary.
- Zand T Paediatric Radiology Unit, Department of Radiology and Nuclear Medicine, University Hospitals of Geneva, 6 rue Willy Donzé, CH-1205 Geneva, Switzerland.
- Hallbäck M Maquet Critical Care AB, Röntgenvägen 2, 17154 Solna, Sweden.
- Wallin M Maquet Critical Care AB, Röntgenvägen 2, 17154 Solna, Sweden.
- Habre W Pathophysiological Experimental Platform, Department of Anaesthesiology, Pharmacology and Intensive Care, University of Geneva, 1 Rue Michel Servet, CH-1205 Geneva, Switzerland ; Paediatric Anaesthesia Unit, Geneva Children's Hospital, University Hospitals of Geneva, 6, Rue Willy Donzé, CH-1205 Geneva, Switzerland.
- 2014-08-22
Published in:
- BMC anesthesiology. - 2014
Capnodynamics
Effective lung volume
Gas exchange
Lung injury
Lung mechanics
Animals
Bronchoalveolar Lavage
Capnography
Helium
Lung
Lung Volume Measurements
Peak Expiratory Flow Rate
Point-of-Care Systems
Pulmonary Surfactants
Rabbits
Respiration, Artificial
Tomography, Spiral Computed
English
BACKGROUND
Bedside assessment of lung volume in clinical practice is crucial to adapt ventilation strategy. We compared bedside measures of lung volume by helium multiple-breath washout technique (EELVMBW,He) and effective lung volume based on capnodynamics (ELV) to those assessed from spiral chest CT scans (EELVCT) under different PEEP levels in control and surfactant-depleted lungs.
METHODS
Lung volume was assessed in anaesthetized mechanically ventilated rabbits successively by measuring i) ELV by analyzing CO2 elimination traces during the application of periods of 5 consecutive alterations in inspiratory/expiratory ratio (1:2 to 1.5:1), ii) measuring EELVMBW,He by using helium as a tracer gas, and iii) EELVCT from CT scan images by computing the normalized lung density. All measurements were performed at PEEP of 0, 3 and 9 cmH2O in random order under control condition and following surfactant depletion by whole lung lavage.
RESULTS
Variables obtained with all techniques followed sensitively the lung volume changes with PEEP. Excellent correlation and close agreement was observed between EELVMBW,He and EELVCT (r = 0.93, p < 0.0001). ELV overestimated EELVMBW,He and EELVCT in normal lungs, whereas this difference was not evidenced following surfactant depletion. These findings resulted in somewhat diminished but still significant correlations between ELV and EELVCT (r = 0.58, p < 0.001) or EELVMBW,He (0.76, p < 0.001) and moderate agreements.
CONCLUSIONS
Lung volume assessed with bedside techniques allow the monitoring of the changes in the lung aeration with PEEP both in normal lungs and in a model of acute lung injury. Under stable pulmonary haemodynamic condition, ELV allows continuous lung volume monitoring, whereas EELVMBW,He offers a more accurate estimation, but intermittently.
Bedside assessment of lung volume in clinical practice is crucial to adapt ventilation strategy. We compared bedside measures of lung volume by helium multiple-breath washout technique (EELVMBW,He) and effective lung volume based on capnodynamics (ELV) to those assessed from spiral chest CT scans (EELVCT) under different PEEP levels in control and surfactant-depleted lungs.
METHODS
Lung volume was assessed in anaesthetized mechanically ventilated rabbits successively by measuring i) ELV by analyzing CO2 elimination traces during the application of periods of 5 consecutive alterations in inspiratory/expiratory ratio (1:2 to 1.5:1), ii) measuring EELVMBW,He by using helium as a tracer gas, and iii) EELVCT from CT scan images by computing the normalized lung density. All measurements were performed at PEEP of 0, 3 and 9 cmH2O in random order under control condition and following surfactant depletion by whole lung lavage.
RESULTS
Variables obtained with all techniques followed sensitively the lung volume changes with PEEP. Excellent correlation and close agreement was observed between EELVMBW,He and EELVCT (r = 0.93, p < 0.0001). ELV overestimated EELVMBW,He and EELVCT in normal lungs, whereas this difference was not evidenced following surfactant depletion. These findings resulted in somewhat diminished but still significant correlations between ELV and EELVCT (r = 0.58, p < 0.001) or EELVMBW,He (0.76, p < 0.001) and moderate agreements.
CONCLUSIONS
Lung volume assessed with bedside techniques allow the monitoring of the changes in the lung aeration with PEEP both in normal lungs and in a model of acute lung injury. Under stable pulmonary haemodynamic condition, ELV allows continuous lung volume monitoring, whereas EELVMBW,He offers a more accurate estimation, but intermittently.
- Language
-
- English
- Open access status
- gold
- Identifiers
-
- DOI 10.1186/1471-2253-14-64
- PMID 25143759
- Persistent URL
- https://folia.unifr.ch/global/documents/221619
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