Novel technologies to detect atelectotrauma in the injured lung

Cyclical recruitment and derecruitment of lung parenchyma (R/D) remains a serious problem in ALI/ARDS patients, defined as atelectotrauma. Detection of cyclical R/D to titrate the optimal respiratory settings is of high clinical importance. Image-based technologies that are capable of detecting changes of lung ventilation within a respiratory cycle include dynamic computed tomography (dCT), synchrotron radiation computed tomography (SRCT), and electrical impedance tomography (EIT). Time-dependent intra-arterial oxygen tension monitoring represents an alternative approach to detect cyclical R/D, as cyclical R/D can result in oscillations of PaO₂ within a respiratory cycle. Continuous, ultrafast, on-line in vivo measurement of PaO₂ can be provided by an indwelling PaO₂ probe. In addition, monitoring of fast changes in SaO₂ by pulse oximetry technology at the bedside could also be used to detect those fast changes in oxygenation.