Tomography system for lung function monitoring
There is a need to assess regional lung function in patients with acute respiratory distress syndrome (ARDS) on mechanical ventilation. EIT PulmonaryScan is the first non-invasive bedside tomography system for monitoring of the lungs, providing real-time breath by breath diagnostic information. This valuable clinical bedside monitoring tool for the optimisation of artificial ventilation therapy offers many advantages over routinely used methods. Monitoring regional lung function can provide additional information since changes in thoracic air content yield large changes in thoracic impedance. In patients with ARDS, the ventilation-induced impedance change in the dependent part of the lungs increases more significantly than in the non-dependent areas when end-expiratory airway pressure (PEEP) is increased; this allows opening of collapsed alveoli in the dependent region of the lungs leading to increased ventilation. Previously it was assumed that the lower inflation point of the PV curve, where volume rapidly increases, could be used for optimising ventilatory pressure settings. However, as EIT has demonstrated, dependent lung regions require significantly higher opening pressure than non-dependent lung regions. This is a significant finding: lungs require a higher area pressure to be fully recruited than can be detected from the global PV curve.
