Korean J Anesthesiol than 10 min and/or the development of mitral regurgitation ≥ grade 3 with a concomitant rise of the mean pulmonary arterial pressure > 30 mmHg. Allogenic packed red blood cells were transfused when the hematocrit level was < 25% throughout the study period. The central temperature, as measured by the PAC, was maintained between 36-37oC with a warm mattress, a forced warm air blanket and fluid warmer as necessary. All the surgical procedures were performed by one surgeon through a median sternotomy and the heart was displaced using posterior pericardial stitches, large (12 × 70 cm) gauze swabs and tissue stabilizer (Octopus Tissue Stabilization SystemⓇ, Medtronic Inc. USA). All the patients were transferred to the intensive care unit after the surgery. The hemodynamic variables obtained from the PAC and FloTrac/VigileoTM system, including the CCI, FCI, SvO2, heart rate (HR), central venous pressure (CVP) and SVRI, were recorded at the following time points: 15 min after induction of anesthesia (baseline, T1), during Y-graft construction with the opened pericardium and the heart in a neutral position (T2), 5 min after stabilizer application for the obtuse marginalis branch anastomosis (T3), 15 min after completion of grafting with the opened pericardium (T4) and 15 min after sternum closure (T5). At T3, the average of 3 consecutive STAT mode cardiac index measurements by the PAC was considered as the CCI and the average of 3 consecutive 20 sec trend cardiac index measurements by the FloTrac/VigileoTM system was considered as the FCI. Of the 3 consecutive measurements by both the PAC and the FloTrac/VigileoTM system, the middle values were acquired at 5 min after applying stabilizer to coincide with the timing of the cardiac output measurement. At the other time points of measurements, the trend for the FCI was set to 5 min. The SVRI was calculated with the CCI. Statistical analyses were performed using SPSS 12.0 (SPSS Inc., Chicago, IL, USA). All the data is expressed as the number of patients or means ± SDs. The data was assessed for a normal distribution of variance with the Shapiro-Wilk test. Repeated Table 2. Hemodynamic Data HR (beats / min) MAP (mmHg) CVP (mmHg) SvO2 (%) CCI (L/min/m2) 2 FCI (L/min/m ) SVRI (dyne s/cm5/m2) T1 60 ± 9 73 ± 10 7 ± 2 78 ± 6 2.8 ± 0.6 2.6 ± 0.4 1,956 ± 549 www.ekja.org T2 62 ± 10 73 ± 7 7 ± 2 76 ± 6 2.7 ± 0.4 2.6 ± 0.4 1,925 ± 382 T3 64 ± 9 76 ± 9 9 ± 3* 68 ± 8* 2.1 ± 0.3* 2.2 ± 0.3* 2,464 ± 469* T4 64 ± 9 73 ± 7 8 ± 3 74 ± 8 2.6 ± 0.5 2.5 ± 0.5 2,361 ± 526 The table presents the hemodynamic data. The data is presented as means ± SDs. T1: 15 min after induction of anesthesia, T2: during Y-graft construction with opened pericardium, T3: 5 min after applying stabilizer for creating an obtuse marginalis branch anastomosis, T4: 15 min after completion of grafting with opened pericardium, T5: 15 min after sternum closure, HR: heart rate, MAP: mean arterial pressure, CVP: central venous pressure, SvO2: mixed venous oxygen saturation, CCI: continuous cardiac index measured by a pulmonary artery catheter, FCI: cardiac index measured by the FloTrac/VigileoTM system, SVRI: systemic vascular resistance index. *P < 0.05 compared to the values at T1. Jo, et al. measurements of ANOVA with the Bonferroni test was used to compare the hemodynamic variables between consecutive measurements. The FCI and CCI were compared using a modified Bland-Altman analysis of agreement for repeated measures, where bias was defined as the average difference between the FCI and CCI values and the limit of agreement was defined as the 2 SDs of the bias [11,12]. The percentage error (2 SDs of the bias/mean cardiac index) was calculated according to Critchley and Critchley [13]. A percentage error of 30% or less was established as the criterion for method interchangeability [13]. Subgroup analyses that compared the FCI and CCI with the same statistical methods were performed according to a LVEF < 40%, and without modification for repeated measures according to a CCI ≤ 2.4 L/min/m2, a MAP of 60-80 mmHg, a SVRI of 1,600-2,600 dyne s/cm5/m2 and the use of norepinephrine. Results OPCAB could be successfully performed in all 50 patients and a total of 250 data pairs could all be recorded and then analyzed. Value 64 (47-77) 38/22 1.8 ± 0.2 49 ± 16 23 30 14 11 24 23 26 T5 66 ± 9* 76 ± 7 7 ± 3 76 ± 7 2.6 ± 0.5 2.6 ± 0.4 2,264 ± 543 239 Table 1. Patients’ Characteristics Variables Age (yr) Gender (male/female) Body surface area (m2) LVEF (%) Diabetes mellitus (DM) Hypertension (HTN) DM + HTN Preoperative cardiac medication Nitrate Beta blocker Calcium channel blocker RAS blocker Values are medians (range), means (SD) or number of patients. RAS blocker: rennin-angiotensin system antagonist.