Flow-related techniques for preoperative goal-directed fluid optimization

Background. Improved postoperative outcome has been demonstratedby perioperative maximization of cardiac stroke volume (SV)with fluid challenges, so-called goal-directed therapy. OesophagealDoppler (OD) has been the most common technique for goal-directedtherapy, but other flow-related techniques and parameters areavailable and they are potentially easier to apply in clinicalpractice. The objective of this investigation was thereforeto use OD for preoperative SV maximization and compare the findingswith a Modelflow determined SV, with an OD estimated correctedflow time (FTc), with central venous oxygenation () and with muscle and brain oxygenation assessedwith near infrared spectroscopy (NIRS). Methods. Twelve patients scheduled for radical prostatectomywere anaesthetized before optimization of SV estimated by OD.A fluid challenge of 200 ml colloid was provided and repeatedif at least a 10% increment in OD SV was obtained. Values werecompared with simultaneously measured values of Modelflow SV,FTc, and muscle and cerebral oxygenation estimated by NIRS. Results. Based upon OD assessment, optimization of SV was achievedafter the administration of 400–800 ml (mean 483 ml) ofcolloid. The hypothetical volumes administered for optimizationbased upon Modelflow and differed from OD in 10 and 11 patients, respectively. Changes in FTcand NIRS were inconsistent with OD guided optimization. Conclusion. Preoperative SV optimization guided by OD for goal-directedtherapy is preferable compared with Modelflow SV, FTc, NIRSand until outcome studies for the latter are available.