Effect of positive end-expiratory pressure on intrapulmonary shunt at different levels of fractional inspired oxygen.

Effect of positive end-expiratory pressure on pulmonary shunt and dynamic compliance during abdominal surgery

“…We assumed that changes in intrapulmonary shunt with PEEP and the difference between induction or no induction of capnoperitoneum would reflect previous studies. 23 24 Power analysis was performed expecting a standard deviation in shunt of 4%, as observed previously, 21 23 and a moderate correlation (0.7) among repeated measures within subjects. A total of 50 patients were required for repeated measures analysis of variance (ANOVA) to detect an interaction between surgery type and PEEP of at least 1.5% additional change in shunt per step in PEEP in one surgery type compared with the other, with a power of 0.8 and significance level of 0.05.…”

Respiratory failure and non-invasive respiratory support during the covid-19 pandemic: an update for re-deployed hospital doctors and primary care physicians

“…Applying positive end expiratory pressure (PEEP) to the airway during expiration can further improve oxygenation by splinting open the alveoli and smaller airways that may otherwise close during expiration in respiratory infection. This reduces deoxygenated blood flowing through areas of poorly ventilated lung (intrapulmonary shunting) and effectively increases the surface area available for gas exchange 1819. PEEP may be indicated alongside increasing FiO 2 when target oxygenation has not been achieved.…”

Optimal positive end-expiratory pressure obtained with titration of a fraction of inspiratory oxygen: a randomized controlled clinical trial

“…Particularly, a high PEEP level can restrict venous flow into the thorax by elevating lung volume and intrathoracic pressure, which reduces the filling of the right ventricle, thereby reducing the left ventricular stroke volume and cardiac output (32). A previous study showed that PEEP did not influence intrapulmonary shunt at a low FiO 2 (0.2-0.3), which we set during titration, while it greatly decreased the shunt at an FiO 2 higher than 0.3 (33). This finding can be explained by the fact that PEEP increases functional residual capacity (FRC), which can counteract an FRC reduction caused by high FiO 2 .…”