Sevoflurane at 1 MAC provides optimal myocardial protection during off-pump CABG

Figures & data

Table I. Demographic and clinical characteristics of the four groups.

	Control (n = 12)	0.75 MAC (n = 12)	1.0 MAC (n = 12)	1.5 MAC (n = 12)	p-value
Age (y)^1	60.08 ± 7.45	57.08 ± 10.01	56.83 ± 9.00	49.92 ± 12.27	0.091
Gender^2
Male	12	10	12	11	0.603
Female	0	2	0	1
Height (cm)^1	174.7 ± 6.4	173.7 ± 9.2	175.0 ± 3.6	173.6 ± 6.0	0.936
Weight (kg)^1	80.6 ± 12.7	79.5 ± 22.9	79.4 ± 11.8	73.2 ± 8.2	0.616
Ejection fraction (%)^1	59 ± 5	57 ± 10	57 ± 8	55 ± 6	0.544
Patients with preoperative elevated cTnI	9	10	8	9
Cardiac function^3
Grade 2	11	10	9	10	0.759
Grade 3	1	2	3	2
Number of bypass grafts^3
1	2	2	2	0	0.677
2	7	6	5	7
3	3	4	5	5
Intra-operative dopamine usage (μg/kg/min)^3	2 (0, 3)	3 (2, 6)	4 (3, 5)	5 (4, 7)^a,b,c	0.006*
Post-operative dopamine usage (μg/kg/min)^3	0 (0, 1)	1 (1, 2)	1 (0, 2)	1 (1, 2)	0.082
Intra-operative nitroglycerin usage (μg/kg/min)^3	2 (1, 2)	2 (1, 4)	1 (1, 1)	2 (1, 3)	0.113
Post-operative nitroglycerin usage (μg/kg/min)^3	2 (1, 2)	1 (1, 2)	1 (1, 1)	1 (1, 2)	0.290
Post-operative drainage (ml)^3
Pericardial	140 (85, 210)	150 (125, 185)	190 (145, 290)	125 (100, 350)	0.630
Mediastinal/thoracic cavity	185 (120, 300)	200 (60, 295)	150 (100, 195)	150 (135, 325)	0.632
Anesthesia time (min)^1	198.3 ± 14.4	197.2 ± 12.9	206.5 ± 15.2	206.0 ± 19.4	0.321
Fentanyl dose (μg/kg)^1	27 ± 2	27 ± 3	27 ± 2	27 ± 3	0.996
Intravenous fluid^1	1814.2 ± 172.5	1797.5 ± 171.9	1777.5 ± 202.1	1924.2 ± 171.9	0.204

Data are presented as mean ± standard deviation or number.

*Significant difference among the four group, p < 0.05.

p-values are based on ¹ANOVA, ²Fisher's exact test, and ³Kruskal Wallis test.

^aIndicates a statistically significant difference between the indicated treatment group and the control group.

^bIndicates a statistically significant difference between the indicated treatment group and 0.75 MAC group.

^cIndicates a statistically significant difference between the 1.0 MAC and 1.5 MAC groups.

Pair-wise multiple comparisons between groups were determined using Bonferroni's adjustment.

Table II. Hemodynamic status of the four groups at each time point.

	Control (n = 12)	0.75 MAC (n = 12)	1.0 MAC (n = 12)	1.5 MAC (n = 12)	p-value
Stroke volume (ml)
Baseline	77 ± 23	90 ± 25	82 ± 25	83 ± 21	0.596
After anesthesia	68 ± 21	79 ± 11	71 ± 15	71 ± 19	0.476
After 15 min sevoflurane	69 ± 18	75 ± 13	72 ± 11	71 ± 18	0.825
After surgery	69 ± 16	70 ± 12	66 ± 11	69 ± 16	0.922
12 h after surgery	68 ± 16	60 ± 12	60 ± 9	62 ± 15	0.424
Stroke volume index (ml/beat/m^2)
Baseline	42 ± 11	48 ± 14	46 ± 14	46 ± 11	0.661
After anesthesia	37 ± 9	43 ± 7	40 ± 9	39 ± 10	0.374
After 15 min sevoflurane	38 ± 8	43 ± 7	40 ± 7	35 ± 12	0.157
After surgery	38 ± 8	38 ± 6	35 ± 7	35 ± 10	0.617
12 h after surgery	38 ± 7	33 ± 5	35 ± 4	33 ± 6	0.094
Cardiac output (L/min)
Baseline	5.7 ± 1.5	6.5 ± 1.7	5.8 ± 1.2	6.3 ± 1.5	0.480
After anesthesia	4.7 ± 1.5	5.1 ± 1.0	4.6 ± 0.7	4.9 ± 1.1	0.718
After 15 min sevoflurane	5.2 ± 1.5	4.8 ± 0.6	4.6 ± 0.7	4.5 ± 0.5	0.234
After surgery	6.4 ± 1.5	5.7 ± 0.9	5.5 ± 1.6	5.7 ± 1.3	0.392
12 h after surgery	6.1 ± 1.3	5.9 ± 1.2	5.8 ± 1.7	6.2 ± 1.2	0.859
Cardiac index (L/min/m^2)
Baseline	3.1 ± 0.7	3.5 ± 0.9	3.2 ± 0.5	3.4 ± 0.7	0.395
After anesthesia	2.6 ± 0.7	2.8 ± 0.6	2.5 ± 0.3	2.7 ± 0.5	0.585
After 15 min sevoflurane	2.9 ± 0.6	2.7 ± 0.3	2.5 ± 0.3	2.5 ± 0.3	0.264
After surgery	3.5 ± 0.9	3.2 ± 0.6	3.0 ± 0.8	3.1 ± 0.6	0.211
12 h after surgery	3.6 ± 0.7	3.3 ± 0.6	3.3 ± 0.6	3.1 ± 0.5	0.653

Data are presented as mean ± standard deviation.

p-values are based on ANOVA.

Table III. cTnI levels at each time point among the four groups.

	Control (n = 12)	0.75 MAC (n = 12)	1.0 MAC (n = 12)	1.5 MAC (n = 12)	p-value for group effect	p-value for time effect
Baseline	0.058 ± 0.029	0.058 ± 0.026	0.059 ± 0.036	0.060 ± 0.031	< 0.001*	< 0.001*
Immediately after surgery	0.608 ± 0.309	0.503 ± 0.249	0.223 ± 0.158	0.207 ± 0.137
24 h after surgery	0.523 ± 0.281	0.413 ± 0.262	0.118 ± 0.111	0.113 ± 0.101
48 h after surgery	0.566 ± 0.311	0.469 ± 0.211	0.150 ± 0.080	0.217 ± 0.214
72 h after surgery	0.668 ± 0.271	0.469 ± 0.201	0.178 ± 0.103	0.155 ± 0.157

Data are presented as mean ± standard deviation.

p-values are based on repeated measurement ANOVA.

Figure 1. Correlation between cTnI and BNP in control subjects. (A) Immediately after surgery in the control group. (B) 24 h after surgery in the control group.

Figure 2. BNP levels at each time point among the four groups.

Figure 3. Cardiac index at each time point among the four groups.

Table IV. Intra-operative data and adverse events among the four groups.

	Control (n = 12)	0.75 MAC (n = 12)	1.0 MAC (n = 12)	1.5 MAC (n = 12)	p-value
Duration in the ICU (h)^1	27.3 ± 9.0	26.1 ± 11.1	21.5 ± 3.1	21.8 ± 2.8	0.146
Extubation time (h)	19.9 ± 8.1	16.1 ± 4.4	13.4 ± 2.7^a	15.3 ± 3.1	0.023*
Duration of hospitalization (d)^1	27.2 ± 10.8	21.9 ± 5.6	20.8 ± 4.5	25.3 ± 4.4	0.094
Adverse events^2
Malignant arrhythmia	2	1	1	1	1.000
Myocardial ischemia	6	6	4	5	0.919
Myocardial infarction	4	2	2	1	0.569
Death	0	1	0	0	1.000
Redo surgery	0	0	1	0	1.000

Data are presented as mean ± standard deviation.

*Significant difference among the four groups, p < 0.05.

p-values are based on ¹independent two sample t test and ²Fisher's exact test.

^aIndicates a statistically significant difference between the indicated treatment group and the control group.

Pair-wise multiple comparisons between groups were determined using Bonferroni's adjustment.

Table V. The wall motion score index data before and after surgery.

	Before surgery	After surgery	p-value
Control group	1.4 ± 0.8	1.3 ± 0.5	0.166
0.75 MAC group	1.8 ± 0.8	1.6 ± 0.7	0.166
1.0 MAC group	2.1 ± 1.2	1.8 ± 0.8	0.266
1.5 MAC group	1.6 ± 0.8	1.1 ± 0.3	0.026*

Data are presented as mean ± standard deviation.

*Significant difference, p < 0.05.

p-values are based on paired t test.

Table VI. Change in wall motion score index before and after surgery among the four groups.

	Control (n = 12)	0.75 MAC (n = 12)	1.0 MAC (n = 12)	1.5 MAC (n = 12)	p-value
Improved	2	2	3	5	0.170
Not changed	10	10	7	7
Worsened	0	0	2	0

p-values are based on Fisher's exact test.