Lung monitoring at the bedside in mechanically ventilated patients

Abstract

It has become clear that mechanical ventilation itself can cause damage to the lung in critically ill patients, also known as ventilator-induced lung injury (VILI). Insight into the mechanisms of VILI has learned that a compromise must be found between positive end-expiratory pressure (PEEP) induced alveolar recruitment and prevention of hyperinflation. Therefore, there is a need for clinicians to optimize the PEEP settings for the individual patient at the bedside. In this review, we will discuss several lung-monitoring techniques to improve patient ventilator settings. Recently, new monitoring tools like electrical impedance tomography (EIT), vibration response imaging, respiratory inductive plethysmography and functional residual capacity (FRC) have been (re-)introduced in our ICU. Nowadays, FRC can be measured without the use of tracer gases and without disconnection from the ventilator. EIT is another noninvasive bedside monitoring tool that provides regional ventilation distribution images and can be used for qualitative and quantitative assessment of regional change in ventilation after a ventilator change. These new noninvasive techniques are discussed and seem promising to help clinicians to improve their ventilator settings in the individual patient at the bedside. In conclusion, both FRC and EIT are promising clinical monitoring systems but clinical studies are needed to prove whether these monitors help the clinician toward effective and better ventilator management.