Feasibility of using stroke volume variaton as the left ventricular preload to draw the cardiac function curve

Abstract

Objective To evaluate the feasibility of using stroke volume variation(SVV)as the left ventricular preload to draw the cardiac function curve. Methods Twenty-seven patients of both sexes, aged 18-64 yr, with body mass index of 18-30 kg/m2, of American Society of Anesthesiologists physical status Ⅱ(New York Heart Association Ⅱ), with abnormal cardiac function, scheduled for elective off-pany coronary artery byp grafting, were enrolled in this study.Twenty-five patients, aged 18-64 yr, with body mass index of 18-30 kg/m2, of American Society of Anesthesiologists physical status Ⅰ(New York Heart Association Ⅰ), with normal cardiac function, scheduled for elective non-cardiac surgery, were also enrolled in this study.SVV and SV were monitored by using a FloTrac/Vigileo™ system.The patients were in the supine position from the end of anesthesia induction to the beginning of surgery.After the hemodynamics was kept stable for 5 min, SVV and SV were recorded.6% hydroxyethyl starch 130/0.4 500 ml was intravenously infused over 20 min.SVV and SV were recorded after volume expansion.Spearman rank-order correlation was used to analyze the relationship between SVV and SV.The quadratic regression analysis was used to draw the SVV-SV curve, and the SVV-SV curve was compared with the Frank-Starling curve. Results Compared with the value before volume expansion, SVV and HR were significantly decreased, and SV was increased after volume expansion in the patients with normal cardiac function, and SVV was decreased after volume expansion in the patients with abnormal cardiac function(P<0.01). SVV was negatively correlated with SV in the patients with normal cardiac function, and r=-0.467(P<0.05). SVV was negatively correlated with SV in the patients with abnormal cardiac function, and r=-0.378(P<0.05). The mirror symmetry was found between the SVV-SV curve in the patients with normal cardiac function and the normal Frank-Starling curve, and the general trend was close.The symmetry was not detected between the SVV-SV curve in the patients with abnormal cardiac function and the Frank-Starling curve in the patients with decreased myocardial contractility, and the general trend was not close. Conclusion For the patients with normal cardiac function, SVV can be used as the left ventricular preload to draw the cardiac function curve. Key words: Stroke volume; Ventricular function