We evaluated the accuracy of noninvasive and continuous total hemoglobin (SpHb) monitoring with the Radical-7(®) Pulse CO-Oximeter in Japanese surgical patients before and after an in vivo adjustment of the first SpHb value to match the first reference value from a satellite laboratory CO-Oximeter. Twenty patients undergoing surgical procedures with general anesthesia were monitored with Pulse CO-Oximetry for SpHb. Laboratory CO-Oximeter values (tHb) were compared to SpHb at the time of the blood draws. Bias, precision, limits of agreement and correlation coefficient of SpHb compared to tHb were calculated before and after SpHb values were adjusted by subtracting the difference between the first SpHb and tHb value from all subsequent SpHb values. Trending of SpHb to tHb and the effect of perfusion index (PI) on the agreement of SpHb to tHb were also analyzed. Ninety-two tHb values were compared to the SpHb. Bias ± 1SD was 0.2 ± 1.5 g/dL before in vivo adjustment and -0.7 ± 1.0 g/dL after in vivo adjustment. Bland-Altman analysis showed limits of agreement of -2.8 to 3.1 g/dL before in vivo adjustment and -2.8 to 1.4 g/dL after in vivo adjustment. The correlation coefficient was 0.76 prior to in vivo adjustment and 0.87 after in vivo adjustment. In patients with adequate perfusion (PI ≥1.4) the correlation coefficient was 0.89. In vivo adjustment of SpHb significantly improved the accuracy in our cohort of Japanese surgical patients. The strongest correlation between SpHb and tHb values was observed in patients with adequate peripheral perfusion suggesting that low perfusion may affect the accuracy of SpHb monitoring.
: Purpose of the studyThe measurement of stroke volume variation (SVV) using the FloTrac TM system (Edwards Lifescience, USA) is useful to estimate cardiac preload. We evaluated the benefits of SVV monitoring for adjusting fluid supplementation during laparoscopic adrenalectomy under anesthesia in patients with pheochromocytoma.
Subjects and MethodsAmong 10 patients who underwent laparoscopic adrenalectomy for pheochromocytoma in our institution from June 2004 to December 2009, SVV was not monitored in 5 patients (group I) and in the other 5 patients (group II), SVV monitoring was performed. Subject age, height and body weight, total volume of fluid supplemented, blood loss, urine output and net fluid in -out balance during the procedure were retrospectively assessed. In those with SVV monitoring, infusion volume was adjusted for SVV less than 13%.
ResultsThere were significant differences in the patient age and body weight between the two groups (group I : 64.2 years old and 55.1 kg ; group II : 43.6 years old and 71.7 kg). Both total infusion volume and urine output were significantly higher in group I compared with group II (5,610 vs. 2,400 ml and 1,125 vs. 750 ml, respectively). Total blood loss was similar between the two groups. Values of the net fluid balance divided by the body weight and total anesthesia period (hr) were significantly lower in group II compared with group I (I ; +13.2 in group I and +6.2 in group II, ml/kg/hr).
ConclusionsThese data suggest that SVV monitoring is helpful to estimate the optimal volume for fluid supplementation and could prevent excessive fluid infusion during surgical procedures.
Hannivoort et al.'s pharmacokinetic model, constructed with a dataset obtained from healthy volunteers, can predict dexmedetomidine concentrations best during continuous infusion under spinal anesthesia.
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