Less invasive indicators of changes in thermodilution cardiac output by ventilatory changes after cardiac surgery.

Background And Objective: We studied whether changes in less invasive, noncalibrated pulse-contour cardiac output (by modified ModelFlow, COmf) and derived stroke volume variations (SVV), as well as systolic and pulse pressure variations, predict changes in bolus thermodilution cardiac output (COtd), evoked by continuous and cyclic increases in intrathoracic pressure by increases in positive end-expiratory pressure (PEEP) and tidal volume (Vt), respectively.

Methods: Prospective study on 17 critically ill postcardiac surgery patients on full mechanical ventilatory support, in the intensive care unit.

Results: In contrast to systolic pressure variation and pulse pressure variation, SVV increased from (mean +/- SD) 6.