Fluid Responsiveness: SVV vs esSVV in Mechanically Ventilated and Spontaneously Breathing Patients

Assessment of the estimated stroke volume variation (esSVV, Nihon Kohden, Japan) in the early postoperative period after OPCAB

In mechanically ventilated patients after OPCAB within two hrs after intervention: passive leg raising (PLR), increased PEEP, and mini-fluid load (mFL) tests will be followed by standard fluid load (sFL). Monitoring: SVVPCA, PPVPCA, esSVV, HLI, PVI, pre-ejection fraction (PEP, echocardiography), CIPCA, esCI and CISTD. Transthoracic echocardiography will be performed to assess the volume of heart chambers, ejection fraction and pre-ejection phase (PEP).

2\) In spontaneously breathing patients at 18 hrs of the postoperative period: PLR, and mFL tests followed by sFL. Monitoring: SVVPCA, PPVPCA, esSVV, PVI, PEP, CIPCA, esCI and CISTD. Transthoracic echocardiography will be performed to assess the volume of heart chambers, ejection fraction and pre-ejection phase.