Regional lung mechanics in mechanically ventilated adults
Research type
Research Study
Full title
Characterisation of regional lung mechanics by analysis of regional sound energy distribution and electrical impedance tomography in mechanically ventilated critically ill patients: a prospective comparative study
IRAS ID
124363
Contact name
Luigi Camporota
Contact email
Sponsor organisation
Guy's and St Thomas' NHS Foundation Trust
Research summary
Patients on ICU are often mechanically ventilated due to respiratory failure. If optimised, ventilation can allow the lungs to recover. However, optimising ventilation is difficult in the presence of lung pathology due to variance in ventilation throughout different lung regions; a pressure optimising one area may cause collapse or over inflation of another, causing lung injury compromising recovery.
Traditionally, global measure of lung performance and lung imaging (Computed Tomography and Chest X-ray) are used to optimise ventilation. However, these do no show how the lungs are affected regionally. Furthermore, these images are a snapshot in time, and therefore may not accurately provide up-to-date information to the clinician, where lung changes and ventilation requirements continuously change. Therefore, the demand for real-time, bedside and non-invasive monitoring systems is increasing. Two non-invasive bedside imaging devices that can show near continuous changes in lung pathology are Electrical Impedance Tomography (EIT) and Vibration Response Imaging (VRI).
EIT use a small electrical current passed between surface electrodes on the chest wall to measure changes in the electrical resistance of structures within the thorax. From this, a moving cross sectional image of lung ventilation is shown and a number of pathologies characterised. However, EIT can only show a section of the whole lung at one time and different pathologies may give the same EIT appearance.
VRI allows visualisation of lung sound distribution during breathing. As lung movement is not necessarily needed for sound generation, VRI can differentiate between pathologies that may look identical on EIT. However, VRI does not provide information on changes in lung volume and ventilation.
Therefore, this study aims to assess the additional diagnostic value of VRI with EIT in differentiating between lung pathologies (e.g., consolidation from pleural effusion) with similar EIT signal but different sound characteristics.
REC name
London - Harrow Research Ethics Committee
REC reference
13/LO/0580
Date of REC Opinion
24 Jun 2013
REC opinion
Further Information Favourable Opinion