Literature List Electrical Impedance Tomography

Electrical impedance tomography (EIT) has the potential to become a bedside tool for monitoring and guiding ventilator therapy as well as tracking the development of chronic lung diseases. This review article summarizes recent publications (from 2011) dealing with the applications of pulmonary EIT. Original papers on EIT lung imaging in clinical settings are analyzed and divided into several categories according to the lung pathology of the study subjects. Studies on children and infants are presented separately from studies on adult patients. Information on the study objectives and main results, the number of studied patients, the performed ventilatory maneuvers or interventions and the analyzed EIT information is given. Limitations that hinder EIT to become a routinely used tool in a clinical setting are also discussed. ES Hammermüller S et al. Quantification of lung collapse during peep-titration by electrical impedance tomography in experimental ards comparison with quantitative ct analysis Intensive Care Medicine Experimental 2015 Dec, 3:A995 Introduction: Tidal recruitment of nonaerated lung is a main cause of ventilator associated lung injury. CT as the gold standard for quantifying lung collapse (CT-collapse) is associated with certain risks for the patient (e.g. radiation exposure or transportation) and cannot be used for repeated assessments. Electrical impedance tomography (EIT) instead is a bedside non-invasive radiation-free continuous technique for monitoring of changes in thoracic air content and distribution. EIT may also allow quantification of recruitable lunge collapse (EIT-collapse) [1]. Objectives: To study correlation and agreement between CTand EIT-collapse during a decremental PEEP-titration after a lung recruitment maneuver (RM) for further validation of the technique for assessment of EIT-collapse. Methods: We induced ARDS in anesthetized pigs by pulmonary acid (HCl) instillation until the PaO2/FiO2 remained stable < 200 mmHg. Tidal volume was 6 ml/kg body weight. We performed a RM (PEEP 40cmH2O; PIP 60cmH2O for 2 min) followed by decremental PEEP titration (starting from 26cmH2O in steps of 2 cmH2O). We recorded EIT-data and airway pressures simultaneously on each step and obtained end-expiratory CTs. CT-collapse in the entire lung was defined as the lung mass within -200 HU to +100 HU [2]. “Non-recruitable collapse” was defined as CT-collapse remaining after RM at PEEP = 26 cmH2O. Recruitable CT-collapse was calculated by multiplying the difference between CT-collapse at a certain PEEP-step and “non-recruitable collapse” by 100% and then dividing this product by the difference between total lung mass and “non-recruitable collapse”. EIT-collapse was calculated based on analysis of changes in EIT-pixel compliance [1]. The latter was estimated considering that local tidal volumes correlate well with local impedance variations. The concept used here assumes that the best compliance of a lung compartment reflects the number of functional lung units in that compartment, which, once opened, have equivalent compliances [1,3]. Thus, the relative amount of collapse (amount of lost units) within a given pixel can be inferred from the decrease in pixel compliance in relation to its “best compliance” [1,3]. Bland-Altman plots and within-subject linear regression were used for statistical analysis [2]. Results: We analyzed 60 data points from 11 pigs (weight 39 (range 37-42) kg). We found a strong within-subject correlation and clinically acceptable agreement between CTand EIT-collapse (Figure 1) [4]. Conclusion: Our results support the potential of EIT for non-invasive bedside assessment of recruitable collapse. Electrical Impedance Tomography (EIT) Literature List