Accuracy Of A Respiratory Resistance Device Assisting Pulse Pressure Variation In Predicting Fluid Responsiveness During Spontaneous Breathing

Object:To evaluate the accuracy of a respiratory resistance device assisting pulse pressure variation(PPV)in predicting volume responsiveness in the spontaneously breathing patients.Methods:Forty spontaneously breathing patients of both sexes,aged 22-61 yr,weighing 51-73 kg,of American Society of Anesthesiologists physical status I or II,undergoing elective operation,were enrolled.Before induction of anesthesia,mean arterial pressure(MAP),heart rate(HR),central venous pressure(CVP),cardiac index(CI)and pulse pressure variation(PPVO)were recorded after haemodynamics were stable.Then the respiratory resistance device was used,and MAP,HR,CVP,CI,PPVE,PPVI were recorded.The device was then removed.Volume expansion was carried out.6%hydroxyethyl starch 130/0.4 6 ml/kg was infused over 10 min.MAP,HR,CVP,CI and PPVO were recorded within 3 min after volume expansion.The device was used again,and 1 min later MAP,HR,CVP,Cl,PPVE and PPVI were recorded.The device was then removed.The patients were divided into 2 groups according the percentage of increase in Cl after volume expansion(ΔCI):ΔCI ≥ 15%considered to be a positive response group(group P),and ΔCI<15%considered to be a negative response group(group N).A receiver-operating characteristic(ROC)curve for PPV was plotted.According to the ROC curve,the diagnostic threshold,sensitivity,specificity,area under the curve,and 95%confidence interval of the respiratory resistance device assisting PPV in predicting volume responsiveness were determined.Results:The area under the curve(95%confidence interval)of PPVE was 0.880(0.70-0.98),the diagnostic threshold was 13.5%,and the sensitivity and specificity in determining volume responsiveness were 87%and 88%,respectively.Area under curve for PPVOand PPVI were 0.57,0.74.The sensitivity and specificity for prediction of fluid responsiveness were 74%and 47%,respectively,for PPVO,78%and 76%,respectively,for PPVI.Compared with the value before administration of the loading dose,the CVP and Cl were significantly increased,PPVO,PPVE and PPVI were decreased after volume expansion in group P,and the CVP and Cl were significantly increased after volume expansion in group N(P<0.05).Compared with group P,PPVE and PPVI were significantly decreased before volume expansion,and the Cl was decreased after volume expansion in group N(P<0.05).Conclusions:The expiratory resistance device can assist PPV in predicting volume responsiveness in the spontaneously breathing patients.