Electrical impedance tomography to determine optimal positive end-expiratory pressure in severe chronic obstructive pulmonary disease

Kostakou, Eirini; Barrett, Nicholas; Camporota, Luigi

doi:10.1186/s13054-016-1475-2

Cited by 20 publications

(13 citation statements)

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“…Air trapping is defined as lung overdistension due to flow limitation in COPD/asthma/ARDS [37,38]. Two cases that reported using EIT technology could be useful to adjust an individual extra-PEEP of mechanical ventilation settings in severe asthma patients [38,39]. In the present study, we did not find any signs of air trapping by EIT (flow limitation) as the flow rate increased.…”

Section: Study Strengths and Limitationscontrasting

confidence: 43%

“…Overinflated regions of lungs might sometimes appear similar to air trapping. Air trapping is defined as lung overdistension due to flow limitation in COPD/asthma/ARDS [37,38]. Two cases that reported using EIT technology could be useful to adjust an individual extra-PEEP of mechanical ventilation settings in severe asthma patients [38,39].…”

Section: Study Strengths and Limitationsmentioning

confidence: 99%

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Effect of postextubation high-flow nasal cannula therapy on lung recruitment and overdistension in high-risk patient

Zhang

Long

et al. 2020

Crit Care

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Background: Postextubation high-flow nasal cannula (HFNC) is used as a support therapy in high-risk patients in ICU. This study aimed to determine the effects of HFNC therapy on lung recruitment and overdistension assessed by electrical impedance tomography (EIT). Methods: Twenty-four patients who received HFNC within 24 h after extubation were prospectively enrolled in this study. EIT was used to monitor regional lung ventilation distributions at baseline (conventional oxygen therapy) and three flow rate levels of HFNC therapy (20, 40, and 60 L/min). Change of end-expiratory lung impedance (ΔEELI), regional recruitment (recruited-pixels) and overdistension (overdistended-pixels), and lung strain change were determined by EIT. EIT images were equally divided into four ventral-to-dorsal horizontal regions of interest (ROIs 1, 2, 3, and 4). "Overdistensionby HFNC " due to HFNC is defined as an increase of overdistened-pixels > 10 than baseline. Patients were divided into two groups: (1) high potential of recruitment (HPR), recruited-pixels > 10 pixels at 60 L/min than baseline, and (2) low potential of recruitment (LPR), recruited-pixels < 10 pixels at 60 L/min than baseline. Results: When the flow rate gradually increased from baseline to 60 L/min, a significant and consistent increasing trend of global ΔEELI (%) (p < 0.0001), recruited-pixels (p < 0.001), and overdistended-pixels (p = 0.101) was observed. Moreover, the increase of ΔEELI was mainly distributed in ROI2 (p = 0.001) and ROI3 (p < 0.0001). The HPR group (13/24 patients) had significantly higher recruited-pixels than the LPR group (11/24 patients) at 20, 40, and 60 L/min. There were no significant differences in PaO 2 /FiO 2 , ΔEELI (%), and overdistention pixels between the two groups. The HPR group had 13 patients in which no one had "overdistensionby HFNC ", and the LPR group had 11 patients in which 4 patients had "overdistensionby HFNC " (0/13 vs. 4/11, p = 0.017). Conclusions: Using EIT could identify diverse effects of HFNC on lung regional ventilation in postextubation situations. Further study is required to validate using "HFNC effect" based on lung recruitment and overdistension by EIT in clinical practice. Trial registration: The study was retrospectively registered at www.clinicaltrials.gov (no. NCT04245241).

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Section: Study Strengths and Limitationscontrasting

confidence: 43%

Section: Study Strengths and Limitationsmentioning

confidence: 99%

Effect of postextubation high-flow nasal cannula therapy on lung recruitment and overdistension in high-risk patient

Zhang

Long

et al. 2020

Crit Care

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“…It is capable of obtaining real‐time, two‐dimensional, cross‐sectional images of the thorax, helping to evaluate the air distribution across the lungs. Its utility has been documented in many scenarios, including pneumothorax, pulmonary edema,positive end‐expiratory pressure (PEEP) titration after recruitment maneuvers, endotracheal tube position, and dynamic hyperinflation …”

Section: Introductionmentioning

confidence: 99%

Electrical impedance tomography monitoring during spontaneous breathing trial: Physiological description and potential clinical utility

Lima

Fontes

Szmuszkowicz

et al. 2019

Acta Anaesthesiol Scand

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Background Readiness for mechanical ventilation (MecV) weaning and extubation is usually assessed clinically with the use of a spontaneous breathing trial (SBT), but its accuracy is limited, and the pathophysiology of weaning failure not completely elucidated. The purpose of the present study was to describe the physiological behavior of electrical impedance tomography parameters during SBT and to propose additional variables that could be helpful in defining weaning/extubation outcome. Methods From December 2015 to January 2017, all subjects who remained under MecV with an orotracheal tube for more than 24 hours and who were submitted to SBT both in pressure‐support ventilation (PSV) or T‐tube were included in the study. Both clinical and impedance parameters were collected immediately before as well as during SBT. Results Forty‐two subjects were included in the final analysis. For subjects submitted to SBT in PSV, none of the impedance parameters added significant information regarding weaning outcomes. For subjects submitted to a T‐tube SBT, a significant and progressive decrease in end‐expiratory lung impedance (dEELI) was observed, which was more prominent in subjects who clinically failed the SBT. These subjects had a significant rapid shallow breathing index at the end of SBT. Conclusions dEELI was a potentially useful parameter in the evaluation of MecV weaning outcome when abrupt lung depressurization was induced during SBT in our study. The degree of dEELI decrease was probably related to the magnitude of lung derecruitment, which seems to play a key role in the MecV weaning outcome.

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“…To date, regional online airflow obstruction measurements in patients with the most severe lung failure have yet to be determined [ 35 , 36 ]. Therefore, the aim of the present study was to develop, evaluate and validate an EIT-based method to measure regional expiratory time constants on a breath by breath basis and pixelwise level.…”

Section: Introductionmentioning

confidence: 99%

Regional expiratory time constants in severe respiratory failure estimated by electrical impedance tomography: a feasibility study

et al. 2018

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BackgroundElectrical impedance tomography (EIT) has been used to guide mechanical ventilation in ICU patients with lung collapse. Its use in patients with obstructive pulmonary diseases has been rare since obstructions could not be monitored on a regional level at the bedside. The current study therefore determines breath-by-breath regional expiratory time constants in intubated patients with chronic obstructive pulmonary disease (COPD) and acute respiratory distress syndrome (ARDS).MethodsExpiratory time constants calculated from the global impedance EIT signal were compared to the pneumatic volume signals measured with an electronic pneumotachograph. EIT-derived expiratory time constants were additionally determined on a regional and pixelwise level. However, regional EIT signals on a single pixel level could in principle not be compared with similar pneumatic changes since these measurements cannot be obtained in patients. For this study, EIT measurements were conducted in 14 intubated patients (mean Simplified Acute Physiology Score II (SAPS II) 35 ± 10, mean time on invasive mechanical ventilation 36 ± 26 days) under four different positive end-expiratory pressure (PEEP) levels ranging from 10 to 17 cmH2O. Only patients with moderate-severe ARDS or COPD exacerbation were included into the study, preferentally within the first days following intubation.ResultsSpearman’s correlation coefficient for comparison between EIT-derived time constants and those from flow/volume curves was between 0.78 for tau (τ) calculated from the global impedance signal up to 0.83 for the mean of all pixelwise calculated regional impedance changes over the entire PEEP range. Furthermore, Bland-Altman analysis revealed a corresponding bias of 0.02 and 0.14 s within the limits of agreement ranging from − 0.50 to 0.65 s for the aforementioned calculation methods. In addition, exemplarily in patients with moderate-severe ARDS or COPD exacerbation, different PEEP levels were shown to have an influence on the distribution pattern of regional time constants.ConclusionsEIT-based determination of breath-by-breath regional expiratory time constants is technically feasible, reliable and valid in invasively ventilated patients with severe respiratory failure and provides a promising tool to individually adjust mechanical ventilation in response to the patterns of regional airflow obstruction.Trial registrationGerman Trial Register DRKS 00011650, registered 01/31/17.Electronic supplementary materialThe online version of this article (10.1186/s13054-018-2137-3) contains supplementary material, which is available to authorized users.

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Electrical impedance tomography to determine optimal positive end-expiratory pressure in severe chronic obstructive pulmonary disease

Cited by 20 publications

References 4 publications

Effect of postextubation high-flow nasal cannula therapy on lung recruitment and overdistension in high-risk patient

Effect of postextubation high-flow nasal cannula therapy on lung recruitment and overdistension in high-risk patient

Electrical impedance tomography monitoring during spontaneous breathing trial: Physiological description and potential clinical utility

Regional expiratory time constants in severe respiratory failure estimated by electrical impedance tomography: a feasibility study

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