dos cm, and continuously monitors the left and right sides of rScO2. The bilateral cerebral oxygen saturation was monitored continuously when the patient entered the operation room. 2) and bispectral index (BIS). After induction of anesthesia, arterial blood pressure (ABP) and end tidal carbon dioxide partial pressure (PetCO2) were also continuously monitored.
The patients was basically confronted with heartrate (HR), noninvasive blood pressure level (NBP), heartbeat outdoors saturation (SpO
Anesthesia was induced by atropine (0.0step one mg/kg), propofol (3 mg/kg), sufentanil (0.5 ?g/kg), and rocuronamine (0.6 mg/kg), and was maintained with propofol (8–10 mg/kg/h) and remifentanil (0.2–0.4 ?g/kg/min). After intubation the tidal volume was adjusted to 8–10 mL/kg and the respiratory rate was adjusted to maintain PetCO2 at 35–45 mmHg. During the operation, the inhaled oxygen concentration was adjusted to 70%, SpO2 was maintained above 95%, and the BIS value was controlled to within 40–60 to ensure an appropriate depth of anesthesia. During the operation, propofol was used to control the depth of anesthesia and remifentanil was used to control patient blood pressure. ABP was maintained within 15% of the baseline level. When blood pressure drops, norepinephrine infusion can be pumped at 0.1 ?g/kg/min at the beginning, and then reduced to 0.01 ?g/kg/min. Atropine 0.01–0.02 mg/kg was given if the heart rate decreased by more than 15%. One hour after entering the operation room, a 20 mL/kg injection of compound sodium lactate and sorbitol was used to give rapid expansion of blood volume. In cases of low blood volume, hydroxyethyl starch was used to expand the volume by 5–10 mL/kg. fdating A cell saver machine was used for blood recovery. Decisions as to whether to infuse concentrated red blood cells and fresh frozen plasma were made based on the patient hemoglobin level. Intraoperative red blood cell volume (Hct) was maintained above 25%. When Hct was lower than 25%, transfusion of autologous blood started after washing. After that, allogeneic red blood cells are supplemented, and plasma is transfused at a ratio of 1:1, if Hct was still lower than 25%. A further determination as to whether the concentrated red blood cells required supplementation was made according to the results of blood gas analysis, rScO2 was recorded when the patient entered the operating room (T0, baseline), after anesthesia induced intubation (T1), after radial artery puncture (T2), and the lowest value of rScO2 during the operation was also recorded. Systolic blood pressure (SBP), HR, SpO2 and PetCO2 values were recorded continuously. Hemoglobin content was recorded before the surgery, the hemoglobin value at the time of the lo west rScO2 and after the operation. Quantities of bleeding and transfusion fluid were recorded.
Analytical research
The main outcome index was set as the difference in hemoglobin level before and after surgery. The results of pre-experiment obtained as the mean values for rScO2 in the L-ScO2 and H-ScO2 groups were 3.50 ± 1.19 and 2.63 ± 1.23, respectively. The sample size was calculated based on comparison of mean value between two independent groups. I addition, we set the type I error ? of the two-tailed test as 0.05, type II error ? as 0.1, and the ratio of observers between L-ScO2 and H-ScO2 as 1:1.5. The sample size calculation formula is as presented below:
n1 is L-ScO2group, n2 is H-ScO2 group, k is 1.5, s is the combined standard deviation of the two groups, and ? is the difference between the mean value of the two groups. The calculated sample size of the L-ScO2 and H-ScO2 groups were 35 and 53. Taking the missing data into consideration, the sample size was increased by 10%, and the sample size is n1 = 39 persons, n2 = 59 persons. Because of the data loss during the experiment, the final sample size of the L-ScO2 and H-ScO2 groups were 35 and 57. The statistical calculations were done using the Statistical Package for the Social Sciences (SPSS) version 24.0. Data are expressed as mean ± standard deviation for normally distributed continuous variables. Continuous variables that did not conform to the normal distribution were represented by the median and quartileparison of cerebral oxygen saturation on the left and right sides was carried out with the paired t-test. The significance of differences between two groups was determined by the t-test for independent samples. Multiple regression analysis was used to determine the risk factors for cerebral oxygen saturation reduction. p < 0.05 was considered statistically significant.
