Modern methods of assessment of lung aeration during mechanical ventilation

Despite the fact that several modes of ventilation are being used, it is not always possible to maintain adequate parameters of gas exchange. In order to provide proper ventilation, it is necessary to assess the lung function. The aim of this article is presentation of different methods of assesment of lung aerations including its advantages, disadvantages and possibilities for implementation in clinical practice. Computed tomography provides information regarding morphology and aeration of lung tissue, but has several limitations: necessity of patients transportation, it cannot be performed in a continuous manner, a quantitative assessment of picture seems to be rather complicated. Ultrasonography is widely used in intensive care and is a noninvasive and bedside method. It gives the opportunity to assess an investigated organ in real time. Its clinical utility in patients with ARDS was proved by Lichtenstein et al. Another technology which has been implemented for the purpose of lungs visualization is electrobioimpedancy (EIT). This new method consists of continuous monitoring of chest electrobioimpedancy changes due to its air content. Unlike to techniques mentioned above, lung images generated with EIT do not provide any information about morphology of affected tissue. The method which indirectly describes the sum of lung interactions is the assessment of quasi-static P/V curve. This method provides information allowing to draw conclusions regarding the usefulness of recruitment maneuvers, but does not provide information regarding the nature of morphologic changes and their location. In the search for the ideal method of lung aeration assessment, it is necessary to define its characteristics, such as noninvasiveness, availability and visualization of tissue morphologic changes in real time.