Antero-posterior signal intensity gradients have also been noted in HP 3He MRI studies of human ventilation [34], [35].
However, human ventilation is not uniform, being punctuated by sighs in which the tidal volume may be three times greater than the volume at rest (12 ).
Riley's choice of 10 L/min to model human ventilation has been used by other modelers (14 ), but we have added a broader range of values to assess the relative importance of variability in minute ventilation.
We chose the pig model since it has high similarity to human, ventilation and circulation parameters can be monitored, inhalations can be performed in a similar way, and sufficient amounts of serum and tissue can be removed for evaluation.
Fluid is not a natural medium for sustaining human life after the fetal stage; human respiration requires ventilation with air.
First, data acquired in pigs cannot automatically be transferred into the clinical scenario; however, it has been shown that CO2 production in pigs is comparable to CO2 production observed in adult humans requiring mechanical ventilation [27].
Whether this concept is applicable in humans on mechanical ventilation and PEEP, however, is still a matter of debate.
English-language studies set in the ICU, in sedated adult humans on mechanical ventilation, which reported the incidence of sub-optimal sedation, were included.
English-language studies set in the ICU, in sedated adult humans on mechanical ventilation, which reported the impact of sedation practice on cost and resource use and patient safety outcomes, were included.
Increased oxidative stress and exaggerated proteolysis in the diaphragm have been linked to the development of VIDD in animal models, but much less is known about the extent to which these phenomena occur in humans undergoing mechanical ventilation in the ICU.
