Evaluation of Regional Pulmonary Ventilation in Spontaneously Breathing Patients with Idiopathic Pulmonary Fibrosis (IPF) Employing Electrical Impedance Tomography (EIT): A Pilot Study from the European IPF Registry (eurIPFreg).

Daniel van der Beck,Silke Tello,Isabel Schmalz,Jochen Wilhelm,Poornima Mahavadi,Ekaterina Krauss,Ruth C. Dartsch,Eckhard Teschner,Andreas Guenther,Werner Seeger,Martina Korfei

doi:10.3390/jcm10020192

Abstract

Objectives: In idiopathic pulmonary fibrosis (IPF), alterations in the pulmonary surfactant system result in an increased alveolar surface tension and favor repetitive alveolar collapse. This study aimed to assess the usefulness of electrical impedance tomography (EIT) in characterization of regional ventilation in IPF. Materials and methods: We investigated 17 patients with IPF and 15 healthy controls from the University of Giessen and Marburg Lung Center (UGMLC), Germany, for differences in the following EIT parameters: distribution of ventilation (TID), global inhomogeneity index (GI), regional impedance differences through the delta of end-expiratory lung impedance (dEELI), differences in surface of ventilated area (SURF), as well as center of ventilation (CG) and intratidal gas distribution (ITV). These parameters were assessed under spontaneous breathing and following a predefined escalation protocol of the positive end-expiratory pressure (PEEP), applied through a face mask by an intensive care respirator (EVITA, Draeger, Germany). Results: Individual slopes of dEELI over the PEEP increment protocol were found to be highly significantly increased in both groups (p < 0.001) but were not found to be significantly different between groups. Similarly, dTID slopes were increasing in response to PEEP, but this did not reach statistical significance within or between groups. Individual breathing patterns were very heterogeneous. There were no relevant differences of SURF, GI or CGVD over the PEEP escalation range. A correlation of dEELI to FVC, BMI, age, or weight did not forward significant results. Conclusions: In this study, we did see a significant increase in dEELI and a non-significant increase in dTID in IPF patients as well as in healthy controls in response to an increase of PEEP under spontaneous breathing. We propose the combined measurements of EIT and lung function to assess regional lung ventilation in spontaneously breathing subjects.

Highlights

Idiopathic pulmonary fibrosis (IPF) is a complex disease process affecting all compartments of the lower respiratory system, from the conducting airways to the lung vasculature.It is associated with a significant reduction in quality of life and life expectancy in general; in absence of treatment, survival ranges between 3 and 5 years from the time of diagnosis [1]
This study provided a detailed analysis of electrical impedance tomography (EIT) measurements in spontaneously breathing idiopathic pulmonary fibrosis (IPF) patients vs. healthy controls (HC) and found a significant increase in end-expiratory lung impedance values for both groups over the period of the positive end-expiratory pressure (PEEP) increment, showing improved ventilation in recruited lung regions
IPF subjects showed a significant increase in the end-expiratory lung impedance in response to PEEP application, but there was no significant difference between spontaneously breathing IPF subjects and HC

Summary

Introduction

Idiopathic pulmonary fibrosis (IPF) is a complex disease process affecting all compartments of the lower respiratory system, from the conducting airways to the lung vasculature.It is associated with a significant reduction in quality of life and life expectancy in general; in absence of treatment, survival ranges between 3 and 5 years from the time of diagnosis [1]. Idiopathic pulmonary fibrosis (IPF) is a complex disease process affecting all compartments of the lower respiratory system, from the conducting airways to the lung vasculature. IPF lungs are characterized by a marked loss of surface tension reducing properties of surfactant, which is known to significantly correlate with the degree of lung restriction [5]. Such an impairment of surface activity is largely caused by changes in the phospholipid profile and by a loss of mature (and functionally active) surfactant proteins (SP) SP-B and SP-C, suggestive of an altered type II cell metabolism

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