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Flow Index accurately identifies breaths with low or high inspiratory effort during pressure support ventilation

Abstract:
Background
Flow Index, a numerical expression of the shape of the inspiratory flow-time waveform recorded during pressure support ventilation, is associated with patient inspiratory effort. The aim of this study was to assess the accuracy of Flow Index in detecting high or low inspiratory effort during pressure support ventilation and to establish cutoff values for the Flow index to identify these conditions. The secondary aim was to compare the performance of Flow index,of breathing pattern parameters and of airway occlusion pressure (P0.1) in detecting high or low inspiratory effort during pressure support ventilation.
Methods
Data from 24 subjects was included in the analysis, accounting for a total of 702 breaths. Breaths with high inspiratory effort were defined by a pressure developed by inspiratory muscles (Pmusc) greater than 10 cmH2O while breaths with low inspiratory effort were defined by a Pmusc lower than 5 cmH2O. The areas under the receiver operating characteristic curves of Flow Index and respiratory rate, tidal volume,respiratory rate over tidal volume and P0.1 were analyzed and compared to identify breaths with low or high inspiratory effort.
Results
Pmusc, P0.1, Pressure Time Product and Flow Index differed between breaths with high, low and intermediate inspiratory effort, while RR, RR/VT and VT/kg of IBW did not differ in a statistically significant way. A Flow index higher than 4.5 identified breaths with high inspiratory effort [AUC 0.89 (CI 95% 0.85–0.93)], a Flow Index lower than 2.6 identified breaths with low inspiratory effort [AUC 0.80 (CI 95% 0.76–0.83)].
Conclusions
Flow Index is accurate in detecting high and low spontaneous inspiratory effort during pressure support ventilation.
Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1186/s13054-021-03855-4

Authors

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Role:
Author
ORCID:
0000-0002-3341-5793
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Institution:
University of Oxford
Division:
MSD
Department:
NDM
Sub department:
Tropical Medicine
Role:
Author
ORCID:
0000-0001-7177-3594


Publisher:
BioMed Central
Journal:
Critical Care More from this journal
Volume:
25
Issue:
1
Article number:
427
Place of publication:
England
Publication date:
2021-12-15
Acceptance date:
2021-12-03
DOI:
EISSN:
1466-609X
ISSN:
1364-8535
Pmid:
34911541


Language:
English
Keywords:
Pubs id:
1331007
Local pid:
pubs:1331007
Deposit date:
2023-03-07
ARK identifier:

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