Accuracy of oscillometric noninvasive blood pressure at the ankle in the lateral position during general anesthesia

Abstract Background This study aimed to evaluate the accuracy of ankle blood pressure measurements in relation to invasive blood pressure in the lateral position. Methods This prospective observational study included adult patients scheduled for elective non-cardiac surgery under general anesthesia in the lateral position. Paired radial artery invasive and ankle noninvasive blood pressure readings were recorded in the lateral position using GE Carescape B650 monitor. The primary outcome was the ability of ankle mean arterial pressure (MAP) to detect hypotension (MAP  140 mmHg) as well as bias (invasive measurement – noninvasive measurement), and agreement between the two methods using the Bland-Altman analysis. Results We analyzed 415 paired readings from 30 patients. The AUC (95% confidence interval [CI]) of ankle MAP for detecting hypotension was 0.88 (0.83–0.93). An ankle MAP of ≤ 86 mmHg had negative and positive predictive values (95% CI) of 99 (97–100)% and 21 (15–29)%, respectively, for detecting hypotension. The AUC (95% CI) of ankle SBP to detect hypertension was 0.83 (0.79–0.86) with negative and positive predictive values (95% CI) of 95 (92–97)% and 36 (26–46)%, respectively, at a cutoff value of > 144 mmHg. The mean bias between the two methods was − 12 ± 17, 3 ± 12, and − 1 ± 11 mmHg for the SBP, diastolic blood pressure, and MAP, respectively. Conclusion In patients under general anesthesia in the lateral position, ankle blood pressure measurements are not interchangeable with the corresponding invasive measurements. However, an ankle MAP > 86 mmHg can exclude hypotension with 99% accuracy, and an ankle SBP < 144 mmHg can exclude hypertension with 95% accuracy

Validity of mini-fluid challenge for predicting fluid responsiveness following liver transplantation

Abstract Background Mini-fluid challenge is a well tested and effective tool to predict fluid responsiveness under various clinical conditions. However, mini-fluid challenge has never been tested in patients with end-stage liver disease. This study investigated whether infusion of 150 ml albumin 5% can predict fluid responsiveness in cirrhotic patients following liver transplant. Methods Fifty patients receiving living donor liver transplant were included in the analysis. Mini-fluid challenge composed of 150 ml of albumin 5% administered over 1 min in three consecutive 50-ml fluid boluses. An additional 350 ml was then infused at a constant rate over 15 min (for a total of 500 ml). Stroke volume (SV) was measured as the product of the subaortic velocity time integral (VTI) and left ventricular outflow tract (LVOT) area. Fluid responsiveness was defined as an increase in SV by ≥15% after the infusion. Results Fifty patients were enrolled in the study. Fourteen patients were classified with Child A, 15 patients with Child B, and 21 patients with Child C cirrhosis. Thirty four patients were fluid responders and 16 patients were fluid non-responders. After 150 ml of albumin 5%, the SV increased significantly in our cohort. The area under receiver operating curve (AUROC) was 0.7 (95% confidence interval [CI] 0.5–0.8, P = 0.005). In subgroup analysis, the SV increased significantly after mini fluid challenge in the Child A group (P = 0.017) but not Child B or C groups (P = 0.3 and 0.29, respectively). The AUROC for mini-fluid challenge in the Child A group was 0.86 (95% confidence interval [CI] 0.6–0.9, P = 0.0004), while mini-fluid challenge failed to discriminate between responders and non-responders in Child B and C groups. Conclusion A mini-fluid challenge of 150 ml albumin 5% can predict fluid responsiveness in liver transplant patients with fair sensitivity and specifiicty. Subgroup analyis revealed that minifluid challenge can predict fluid responsiveness in patients with Child A cirrhosis but not patients with Child B or C cirrhosis. Trial registration NCT03396159. (Prospective registered). Initial registration date was 10/01/2018