Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning
Abstract Background Spontaneous breathing trials (SBTs) on a T-piece can be difficult in patients with prolonged weaning because of remaining de-recruitment phenomena and/or insufficient ventilation. There is no clinically established method existent other than experience for estimating whether an S...
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doaj-7639487e0adb4749b8c4aeb233f24ab12020-11-24T21:32:28ZengBMCCritical Care1364-85352017-07-012111810.1186/s13054-017-1758-2Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaningJohannes Bickenbach0Michael Czaplik1Mareike Polier2Gernot Marx3Nikolaus Marx4Michael Dreher5Department of Intensive Care Medicine, University Hospital of the RWTH AachenDepartment of Anesthesiology, University Hospital RWTH AachenDepartment of Intensive Care Medicine, University Hospital of the RWTH AachenDepartment of Intensive Care Medicine, University Hospital of the RWTH AachenDepartment of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital RWTH AachenDepartment of Cardiology, Pneumology, Angiology and Intensive Care Medicine, University Hospital RWTH AachenAbstract Background Spontaneous breathing trials (SBTs) on a T-piece can be difficult in patients with prolonged weaning because of remaining de-recruitment phenomena and/or insufficient ventilation. There is no clinically established method existent other than experience for estimating whether an SBT is most probably beneficial. Electrical impedance tomography (EIT) is a clinical useful online monitoring technique during mechanical ventilation, particularly because it enables analysis of effects of regional ventilation distribution. The aim of our observational study was to examine if EIT can predict whether patients with prolonged weaning will benefit from a planned SBT. Methods Thirty-one patients were examined. Blood gas analysis, vital parameter measurements, and EIT recordings were performed at three time points: (1) baseline with pressure support ventilation (PSV) (t0), (2) during a T-piece trial (t1), and (3) after resumption of PSV (t2). Calculation of EIT parameters was performed, including the impedance ratio (IR), the tidal variation of impedance (TIV), the changes in end-expiratory lung impedance (ΔEELI), the global inhomogeneity index (GI), and the regional ventilation delay (RVD) index with use of different thresholds of the percentage inspiration time (RVD40, RVD60, RVD80). The predictive power of the baseline GI with regard to clinical impairment of an SBT was analyzed by means of ROC curves. Clinical deterioration was assumed when tidal volume was decreased by at least 20 ml after the T-piece trial, measured at t2. Results Partial pressure of arterial oxygen significantly decreased at t1 (71 ± 15 mmHg) compared with t0 (85 ± 17 mmHg, p < 0.05) and t2 (82 ± 18 mmHg, p < 0.05). The IR trended toward higher values during t1. At t1, TIV and ΔEELI significantly decreased. The GI was significantly increased at t1 (t0 59.3 ± 46.1 vs t1 81.5 ± 62.5, p = 0.001), as were all RVD indexes. Assuming a GI cutoff value of >40, sensitivity of 85% and specificity of 50% were reached for predicting an increased future tidal volume. Conclusions EIT enables monitoring of regional ventilation distribution during SBTs and is suitable to estimate whether an SBT probably will be beneficial for an individual patient. Therefore, the application of EIT can support clinical decisions regarding patients in the phase of prolonged weaning.http://link.springer.com/article/10.1186/s13054-017-1758-2Mechanical ventilationVentilatory heterogeneityElectrical impedanceTomographyProlonged weaning |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Johannes Bickenbach Michael Czaplik Mareike Polier Gernot Marx Nikolaus Marx Michael Dreher |
spellingShingle |
Johannes Bickenbach Michael Czaplik Mareike Polier Gernot Marx Nikolaus Marx Michael Dreher Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning Critical Care Mechanical ventilation Ventilatory heterogeneity Electrical impedance Tomography Prolonged weaning |
author_facet |
Johannes Bickenbach Michael Czaplik Mareike Polier Gernot Marx Nikolaus Marx Michael Dreher |
author_sort |
Johannes Bickenbach |
title |
Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
title_short |
Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
title_full |
Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
title_fullStr |
Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
title_full_unstemmed |
Electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
title_sort |
electrical impedance tomography for predicting failure of spontaneous breathing trials in patients with prolonged weaning |
publisher |
BMC |
series |
Critical Care |
issn |
1364-8535 |
publishDate |
2017-07-01 |
description |
Abstract Background Spontaneous breathing trials (SBTs) on a T-piece can be difficult in patients with prolonged weaning because of remaining de-recruitment phenomena and/or insufficient ventilation. There is no clinically established method existent other than experience for estimating whether an SBT is most probably beneficial. Electrical impedance tomography (EIT) is a clinical useful online monitoring technique during mechanical ventilation, particularly because it enables analysis of effects of regional ventilation distribution. The aim of our observational study was to examine if EIT can predict whether patients with prolonged weaning will benefit from a planned SBT. Methods Thirty-one patients were examined. Blood gas analysis, vital parameter measurements, and EIT recordings were performed at three time points: (1) baseline with pressure support ventilation (PSV) (t0), (2) during a T-piece trial (t1), and (3) after resumption of PSV (t2). Calculation of EIT parameters was performed, including the impedance ratio (IR), the tidal variation of impedance (TIV), the changes in end-expiratory lung impedance (ΔEELI), the global inhomogeneity index (GI), and the regional ventilation delay (RVD) index with use of different thresholds of the percentage inspiration time (RVD40, RVD60, RVD80). The predictive power of the baseline GI with regard to clinical impairment of an SBT was analyzed by means of ROC curves. Clinical deterioration was assumed when tidal volume was decreased by at least 20 ml after the T-piece trial, measured at t2. Results Partial pressure of arterial oxygen significantly decreased at t1 (71 ± 15 mmHg) compared with t0 (85 ± 17 mmHg, p < 0.05) and t2 (82 ± 18 mmHg, p < 0.05). The IR trended toward higher values during t1. At t1, TIV and ΔEELI significantly decreased. The GI was significantly increased at t1 (t0 59.3 ± 46.1 vs t1 81.5 ± 62.5, p = 0.001), as were all RVD indexes. Assuming a GI cutoff value of >40, sensitivity of 85% and specificity of 50% were reached for predicting an increased future tidal volume. Conclusions EIT enables monitoring of regional ventilation distribution during SBTs and is suitable to estimate whether an SBT probably will be beneficial for an individual patient. Therefore, the application of EIT can support clinical decisions regarding patients in the phase of prolonged weaning. |
topic |
Mechanical ventilation Ventilatory heterogeneity Electrical impedance Tomography Prolonged weaning |
url |
http://link.springer.com/article/10.1186/s13054-017-1758-2 |
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