Functional residual capacity, thoracoabdominal dimensions, and central blood volume during general anesthesia with XXXX and mechanical ventilation.

@entity2541 @entity1568 @entity4589 @entity1508
Functional residual capacity (FRC), rib cage and abdominal dimensions (rc-ab), central blood volume (CBV), and extra vascular lung water (EVLW) were measured in six lung-healthy subjects awake and during @entity1508 anesthesia, @entity4589 , and mechanical ventilation. FRC was assessed by multiple breath @entity1568 washout, rc-ab dimensions by computerized tomography, and CBV and EVLW by a double-indicator dilution technique (thermo-dye). During anesthesia, FRC decreased by 0.5 1 (17%). The cross-sectional chest area was reduced by 12-20 cm2, causing an approximate reduction in thoracic volume by 0.3 1. Concomitantly, the diaphragm was moved cranially by an average of 1.9 cm, diminishing the thoracic volume a further 0.5 1. The abdominal cross-sectional area did not alter significantly, despite the shift of the diaphragm. @entity2541 decreased by 0.3 1. EVLW did not change significantly. It is concluded that the thoracic volume is reduced during @entity1508 anesthesia, @entity4589 , and mechanical ventilation as a result of cranial shift of the diaphragm and reduction in transverse area. The decrease in thoracic volume is accompanied by a reduction in FRC and a displacement of blood from the thorax to the abdomen, the transverse area of the latter thus being maintained despite the shift of the diaphragm.
