Measurement of Alveolar Recruitment at the Bedside: The Beginning of a New Era in Respiratory Monitoring?

Clinical review: Lung imaging in acute respiratory distress syndrome patients - an update

“…However, this method requires manual delineation of seven polygonal regions of interest in the posterior intercostal spaces, using dedicated software in anesthetized and paralyzed patients and only the ratio of densities between each PEEP can be calculated [64]. At the present time, therefore, this method can not be routinely used [65]. …”

Modelling mixing within the dead space of the lung improves predictions of functional residual capacity

“…Higher PEEP levels can help to reopen parts of the lung, recruiting alveolar units and reducing alveoli collapse, but there are several draw backs, including the potential inhibition of capillary blood flow (Dushianthan et al, 2011;Soni and Williams, 2008). Trials have shown clinical improvements when using higher PEEP within ALI patients, but in general there has been no improvement in mortality (Dushianthan et al, 2011;Rouby et al, 2013).…”

“…Imaging techniques have been used to assess the response to higher PEEP (Dushianthan et al, 2011;Rouby et al, 2013), but this is a discrete form of monitoring, rather than a continuous one, and is often impractical in ventilated patients (Schmidt, 2012). Selection of appropriate PEEP levels based on pressure-volume curve analysis or a patient's oxygenation level has been advocated, but uncertainties remain with regard to the best way to determine the optimum PEEP level (Miller et al, 2012;Schmidt, 2012;Soni and Williams, 2008).…”

“…Selection of appropriate PEEP levels based on pressure-volume curve analysis or a patient's oxygenation level has been advocated, but uncertainties remain with regard to the best way to determine the optimum PEEP level (Miller et al, 2012;Schmidt, 2012;Soni and Williams, 2008). FRC measurement to guide PEEP levels has been advocated for some time, but has not been used in routine clinical practice (Cortes and Marini, 2013;Hedenstierna, 1993;Rouby et al, 2013). Early methods relied on mass spectrometers (Gothard et al, 1980;Mitchell et al, 1982;Sivan et al, 1990;Williams et al, 1997), but they are bulky, temperamental and becoming harder to source (Arieli, 2010;Hahn, 1996;Horsley et al, 2014), so have not been used in clinical practice.…”

“…Early methods relied on mass spectrometers (Gothard et al, 1980;Mitchell et al, 1982;Sivan et al, 1990;Williams et al, 1997), but they are bulky, temperamental and becoming harder to source (Arieli, 2010;Hahn, 1996;Horsley et al, 2014), so have not been used in clinical practice. More recently, several methods which do not use mass spectrometers have been proposed (Brewer et al, 2011;Olegård et al, 2005;Weismann et al, 2006), but further validation is needed before they are recommended for routine clinical use (Rouby et al, 2013).…”