Reproducibility of regional lung ventilation distribution determined by electrical impedance tomography during mechanical ventilation

Frerichs, Inéz; Schmitz, Gunnar; Pulletz, Sven; Schädler, Dirk; Zick, Günther; Scholz, Jens; Weiler, Norbert

doi:10.1088/0967-3334/28/7/s19

Cited by 74 publications

(60 citation statements)

References 21 publications

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“…The high reproducibility of this EIT measurement method has been reported previously (26). Measurements were performed using the Gottingen Goe-MF II electrical impedance tomograph (VIASYS Healthcare, Hochberg, Germany), delivering current injections through sixteen Ag/AgCI electrodes (Kendall, Kittycat 1,050NPSM, Tyco Healthcare group, Mansfield, MA) placed around the infants' chest at the level of the nipples.…”

Section: Methodsmentioning

confidence: 99%

Effect of time and body position on ventilation in premature infants

2016

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Section: Methodsmentioning

confidence: 99%

Effect of time and body position on ventilation in premature infants

2016

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“…For each scan, the amplitudes of relative impedance changes (rel.ΔZ) were calculated pixel-wise (matrix of 32 × 32) and normalized to obtain the percentaged distribution of Vt (15,16). Using an established approach, ventrodorsal profiles of regional percentaged Vt distribution were computed for all 32 horizontal layers (17,18). To present the changes in regional ventilation distribution between the different I:E ratios, regional ventilation difference profiles to I:E 1:4 were generated and the geometrical centers of ventilation (COVs) were assessed (19), representing the location of maximal ventilation within the anteroposterior chest diameter in percent.…”

Section: Assessment Of Regional Ventilation Distribution By Eitmentioning

confidence: 99%

Influence of Inspiration to Expiration Ratio on Cyclic Recruitment and Derecruitment of Atelectasis in a Saline Lavage Model of Acute Respiratory Distress Syndrome*

Boehme

Bentley

Hartmann

et al. 2015

Critical Care Medicine

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e65Objective: Cyclic recruitment and derecruitment of atelectasis can occur during mechanical ventilation, especially in injured lungs. Experimentally, cyclic recruitment and derecruitment can be quantified by respiration-dependent changes in Pao 2 (ΔPao 2 ), reflecting the varying intrapulmonary shunt fraction within the respiratory cycle. This study investigated the effect of inspiration to expiration ratio upon ΔPao 2 and Horowitz index. Design: Prospective randomized study.Setting: Laboratory investigation. Subjects: Piglets, average weight 30 ± 2 kg. Interventions: At respiratory rate 6 breaths/min, end-inspiratory pressure (P endinsp ) 40 cm H 2 O, positive end-expiratory pressure 5 cm H 2 O, and Fio 2 1.0, measurements were performed at randomly set inspiration to expiration ratios during baseline healthy and mild surfactant depletion injury. Lung damage was titrated by repetitive surfactant washout to induce maximal cyclic recruitment and derecruitment as measured by multifrequency phase fluorimetry. Regional ventilation distribution was evaluated by electrical impedance tomography.Step changes in airway pressure from 5 to 40 cm H 2 O and vice versa were performed after lavage to calculate Po 2 -based recruitment and derecruitment time constants (TAU). Measurements and Main Results: In baseline healthy, cyclic recruitment and derecruitment could not be provoked, whereas in model acute respiratory distress syndrome, the highest ΔPao 2 were routinely detected at an inspiration to expiration ratio of 1:4 (range, 52-277 torr [6.9-36.9 kPa]). Shorter expiration time reduced cyclic recruitment and derecruitment significantly (158 ± 85 torr [21.1 ± 11.3 kPa] [inspiration to expiration ratio, 1:4]; 25 ± 12 torr [3.3 ± 1.6 kPa] [inspiration to expiration ratio, 4:1]; p < 0.0001), whereas the Pao 2 /Fio 2 ratio increased (267 ± 50 [inspiration to expiration ratio, 1:4]; 424 ± 53 [inspiration to expiration ratio, 4:1]; p < 0.0001). Correspondingly, regional ventilation redistributed toward dependent lung regions (p < 0.0001). Recruitment was much faster (TAU: fast 1.6 s [78%]; slow 9.2 s) than derecruitment (TAU: fast 3.1 s [87%]; slow 17.7 s) (p = 0.0078). Conclusions: Inverse ratio ventilation minimizes cyclic recruitment and derecruitment of atelectasis in an experimental model of surfactant-depleted pigs. Time constants for recruitment and derecruitment, and regional ventilation distribution, reflect these findings and highlight the time dependency of cyclic recruitment and derecruitment. (Crit Care Med 2015; 43:e65-e74)

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“…Nevertheless, we were able to detect differences between preterm and termborn infants using AUC ant . In ventilated animals EIT has been shown to be highly reproducible [35], but no data on reproducibility or repeatability has been published so far for spontaneously breathing infants. We can clearly show an excellent shortterm repeatability making EIT a robust technique in the assessment of spontaneously breathing infants.…”

Section: Comparison With Other Studiesmentioning

confidence: 99%

Regional and overall ventilation inhomogeneities in preterm and term-born infants

et al. 2008

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Objectives: We compared ventilation inhomogeneity assessed by electrical impedance tomography (EIT) and multiple breath washout (MBW) in preterm and term-born infants. We hypothesised that EIT measurements in spontaneously breathing infants are repeatable and that differences in regional ventilation distribution measured by EIT can distinguish between preterm and term-born infants. Design: Cross-sectional group comparison study. Setting: Lung function laboratory at a University Children's Hospital. Participants: Seventeen healthy term-born and 15 preterm infants at a matched postmenstrual age of 44 weeks. Measurements and results: We concurrently measured ventilation inhomogeneity by EIT, ventilation inhomogeneity (LCI) and functional residual capacity (FRC) by MBW and tidal breathing variables during unsedated quiet sleep. EIT measurements were highly repeatable (coefficient of variation 3.6%). Preterm infants showed significantly more ventilation of the independent parts of the lungs compared to healthy term-born infants assessed by EIT (mean difference 5.0, 95 CI 1.3-8%). Whereas the two groups showed no differences in lung volumes or ventilation inhomogeneities assessed by MBW, EIT discriminated better between term and preterm infants. (FRC/kg: mean difference 1.1 mL, 95% CI -1.4-3.8 mL; LCI: mean difference 0.03, 95% CI -0.32-0.25). Conclusions: EIT shows distinct differences in ventilation distribution between preterm and term-born infants, which cannot be detected by MBW. Although preterm infants are capable of dynamically maintaining overall functional residual volume and ventilation distribution, they show some spatial differences from fullterm infants.

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Reproducibility of regional lung ventilation distribution determined by electrical impedance tomography during mechanical ventilation

Cited by 74 publications

References 21 publications

Effect of time and body position on ventilation in premature infants

Effect of time and body position on ventilation in premature infants

Influence of Inspiration to Expiration Ratio on Cyclic Recruitment and Derecruitment of Atelectasis in a Saline Lavage Model of Acute Respiratory Distress Syndrome*

Regional and overall ventilation inhomogeneities in preterm and term-born infants

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