Ability Of Stroke Volume Variations To Predict Fluid Responsiveness During Laparoscopic Surgery With Lithotomy And Head-down Position

Objectives: To investigate the influence of pneumoperitoneum (PP) andposture on stroke volume variation(SVV)and to evaluate the ability of strokevolume variations to predict fluid responsiveness in lithotomy with head-downposition during laparoscopic surgery.Methods: Forty ASAⅠorⅡpatients (5male,35female) aged40～65yr,with body mass index from20㎏/㎡to25㎏/㎡,undergoing laparoscopicsurgery under general anesthesia were studied. On arrival to the operatingtheatre, a baseline volume administration of compound sodium chlorideinjection8ml/kg was intravenous transfused in30min before induction. Acatheter was placed in a radial artery with local anaesthesia, The radialcatheter was connected to a FloTrac transducer (Edwards Lifesciences, Irvine,CA, USA) with one connection to the clinical monitor (Philips IntellivueMP50), and the other to a Vigileo monitor to obtain CO,CI,SV,SVI andSVV continuously. Anaesthesia was induced in the supine position withfentanyl (4μg/kg), propofol (2mg/kg), and cis-atracurium (0.15mg/kg) andmaintained with sevoflurane at a expiratory concentration of2%-3%. Thetrachea was intubated and mechanical ventilation was set up usingvolume-controlled ventilation with tidal volume8ml/kg, inspiratory toexpiratory ratio1:2, and change ventilatory frequency to achieve an end-tidalcarbon dioxide partial pressure between35and45mmHg. After induction ofanaesthesia, baseline registrations of variables were obtained, followed by alithotomy position. After establishing pneumoperitoneum, patients wereturned to head-down position. And then6%hydroxyethyl statch (HES130/0.4)500ml was given in30min. Increase in CI by15%was considered effectivevolume expansion. The ROC curve for SVV in determining the volume expansion efficacy was plotted. The area under the curve for SVV and95％confidence interval were calculated. MAP,HR,CO,CI,SV,SVI and SVVwere made after intubation(T₀), after establishing the lithotomy position(T₁),after establishing pneumoperitoneum(T₂), before (T₃) and after (T₄) volumeexpansion, after deflation of pneumoperitoneum(T₅).Results: Lithotomy and head-down position did not induces a significantchange in SVV (both P value＞0.05).SVV decreased from10.75to9.51aspneumoperitoneum was established(P＜0.05).26were responders and14werenon-responders. After volume expansion, MAP,CO,SV,SVI were increasedwhile HR,CI,SVV(P＜0.05) decreased. There was no correlation betweenΔSVV and ΔCI (r=-0.13,P＞0.05). A9.2%SVV threshold discriminatedbetween responders and non-responders with a sensitivity of61%and aspecificity of50%,AUC=0.567(95%CI:0.378～0.757).Conclusions: PneumoPeritoneum decreased the ability of SVV measuredby the FloTrac-Vigileo system to predict fluid responsiveness in patientsundergoing laparoscopic surgery with lithotomy and head-down position.