Prediction of fluid responsiveness in patients during cardiac surgery.
BACKGROUND
Left ventricular stroke volume variation (SVV) has been shown to be a predictor of fluid responsiveness in various subsets of patients. However, the accuracy and reliability of SVV are unproven in patients ventilated with low tidal volumes.


METHODS
Fourteen patients were studied immediately after coronary artery bypass grafting (CABG). All patients were mechanically ventilated in pressure-controlled mode [tidal volume 7.5 (1.2) ml kg(-1)]. In addition to standard haemodynamic monitoring, SVV was assessed by arterial pulse contour analysis. Left ventricular end-diastolic area index (LVEDAI) was determined by transoesophageal echocardiography. A transpulmonary thermodilution technique was used for measurement of cardiac index (CI), stroke volume index (SVI) and intrathoracic blood volume index (ITBI). All variables were assessed before and after a volume shift induced by tilting the patients from the anti-Trendelenburg (30 degrees head up) to the Trendelenburg position (30 degrees head down).


RESULTS
After the change in the Trendelenburg position, SVV decreased significantly, while CI, SVI, ITBI, LVEDAI, central venous pressure (CVP) and pulmonary artery occlusion pressure (PAOP) increased significantly. Changes in SVI were significantly correlated to changes in SVV (r=0.70; P<0.0001) and to changes in LVEDAI, ITBI, CVP and PAOP. Only prechallenge values of SVV were predictive of changes in SVI after change from the anti-Trendelenburg to the Trendelenburg position.


CONCLUSIONS
In patients after CABG surgery who were ventilated with low tidal volumes, SVV enabled prediction of fluid responsiveness and assessment of the haemodynamic effects of volume loading.
Rex
S
S
Department of Anaesthesiology, Rheinisch-Westfälische Technische Hochschule, Aachen, Germany. srex@ukaachen.de
Brose
S
S
Metzelder
S
S
Hüneke
R
R
Schälte
G
G
Autschbach
R
R
Rossaint
R
R
Buhre
W
W
D000368:Aged; D000369:Aged, 80 and over; D000886:Anthropometry; D001026:Coronary Artery Bypass; D005440:Fluid Therapy; D018475:Head-Down Tilt; D006439:Hemodynamics; D006801:Humans; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011182:Postoperative Care / Q000379:methods; D012121:Respiration, Artificial / Q000379:methods; D013318:Stroke Volume; D013990:Tidal Volume; D016277:Ventricular Function, Left