Discussion
arrhythmias, AIS
ARRHYTHMIAS, ABNORMAL LEFT VENTRICULAR FUNCTION, SEVERE AORTIC VALVE REGURGITATION
To our knowledge, this is the first study evaluating the diagnostic performance of IJVV in predicting fluid responsiveness in patients with AIS undergoing PSF surgeries with low Vt ventilation. The main finding of our study was that baseline IJVV was not a good predictor of fluid responsiveness in patients in the prone position under protective ventilation. Second, our findings indicated that the baseline value of PPV and SVV did not predict fluid responsiveness when a lung-protective ventilatory strategy and prone position were applied; moreover, the combination of IJVV and PPV was unreliable in predicting fluid responsiveness in this surgical setting.AIS is a form of lateral curvature of the spine, which occurs in the absence of an explicit medical cause [Previous studies have demonstrated that prone position induces a lot of physiologic changes in the respiratory and cardiovascular system. Specifically, it may decrease cardiac index and the compliance of the respiratory system; and increase CVP, PPV, and SVV [Over the past several decades, enormous efforts have been made to discover non-invasive measures and alternatives to assess volume status. IJVV, a noninvasive and easily determined predictor, has recently been confirmed to accurately assess fluid responsiveness in multiple clinical settings [Conflicting results have been found regarding the ability of PPV and SVV to predict fluid responsiveness in the prone position and under protective ventilation [A 6% HES 130/0.4 infusion was selected to maintain a sustained plasma volume expansion equal to the amount administered [Collectively, our findings suggested that the development of more specific indicators is warranted. Interestingly, recent studies have demonstrated that tidal volume challenge (Vt adjustment from 6 to 8 ml·kgThe present study has several limitations. First, all measurements were performed by the same operator, technical errors might have existed, because even slight pressure might have caused significant changes in IJV diameter and cross-sectional images during the measurement of IJVV. However, intra-observer variability was not calculated in this study. Second, because we did not measure IAP in this study, we could not estimate the effect of IAP on the predictive values of target hemodynamic parameters in the prone position. Third, the single-center nature of the present study may limit the generalizability of the findings. Fourth, we conducted this study on a limited number of patients, and type II error might have been present; thus, additional studies with larger sample sizes might be necessary to identify statistical differences. Fifth, our results were based on patients in the prone position, in which six pads were used to allow the abdomen to hang completely freely. Because other positions can cause different alterations in hemodynamic and respiratory mechanics, the results might differ for various types of operating frames or tables used. Sixth, although validation of the FloTrac/Vigileo device in measuring CO has been confirmed by numerous studies, the accuracy of this uncalibrated system is still a matter of debate involving patients with severe aortic valve regurgitation, severe arrhythmias and abnormal left ventricular function, using high-dose vasopressor as well as undergoing laparoscopic procedures [