Different oxidative stress marker levels in blood from the operated knee or the antecubital vein in patients undergoing knee surgery: A tourniquet-induced ischemia–reperfusion model

Figures & data

Table 1. Demographic and physical data

	Group K	Group V	P values
Gender (M/F)	5/12	5/10
Age (years)	69 ± 7	71 ± 5	0.3428
Weight (kg)	77 ± 6	77 ± 5	0.9269
BMI (kg/m^2)	28 ± 3	27 ± 3	0.7948
Tourniquet time (minutes)	90.3 ± 15.9	92.0 ± 11.1	0.7421
Mean arterial pressure (mmHg)
Five minutes before tourniquet inflation	96 ± 14	93 ± 9	0.4933
Sixty minutes after tourniquet inflation	99 ± 14	96 ± 10	0.5768
Five minutes after tourniquet deflation	95 ± 15	95 ± 10	0.9772
Heart rate (bpm)
Five minutes before tourniquet inflation	71 ± 12	73 ± 9	0.6524
Sixty minutes after tourniquet inflation	69 ± 12	70 ± 11	0.7491
Five after tourniquet deflation	73 ± 11	72 ± 10	0.7794

Values expressed as mean ± SD. Differences were analyzed with two-tailed tests for non-parametric data: Mann–Whitney U and Wilcoxon tests. P values of <0.05 were considered statistically significant. No differences were found between patients undergoing total knee replacement, divided into two groups: group K, n = 17 (blood collected from a drainage tube placed in the operated knee) and group V, n = 15 (blood collected from the antecubital vein).

Figure 1. Time course of oxidized glutathione (GSSG) blood levels in patients undergoing total knee replacement. Values expressed as mean ± SD. Differences were analyzed with two-tailed tests for non-parametric data: Mann–Whitney U and Wilcoxon tests. P values of <0.05 were considered statistically significant. Patients were divided into two groups: group K, n = 17 (blood collected from a drainage tube placed in the operated knee), and group V, n = 15 (blood collected from a antecubital vein). Time course study: before surgery (T₀) and after tourniquet deflation at different times: 3, 10, and 60 minutes (T₁, T₂, and T₃, respectively). Statistical differences were observed in the same group (T₀ vs. T₁ or T₂ or T₃): *P < 0.05; **P < 0.01; ***P < 0.001. Statistical differences were observed between both groups (K vs. R): ^†P < 0.05; ^††P < 0.01; ^†††P < 0.001.

Table 2. Time course of glutathione oxidation and lipid peroxidation marker levels in blood in patients undergoing total knee replacement

Times	T0	T1	T2	T3
GSH (nmol/ml)
K	599 ± 200	409 ± 199***	320 ± 186***	454 ± 219**
V	587 ± 177	534 ± 148*,^†	480 ± 171**,^†	474 ± 109**
GSSG (nmol/ml)
K	11.7 ± 6.5	19.4 ± 10.3***	32.2 ± 17.7**	13.6 ± 5.2*
V	11.1 ± 5.2	13.0 ± 4.5^†	16.8 ± 6.5**,^††	11.5 ± 4.4
[2GSSG/(GSH + 2GSSG)] × 100
K	4.03 ± 2.03	10.45 ± 6.53**	17.64 ± 8.67***	7.66 ± 4.14*
V	3.73 ± 1.55	4.58 ± 1.80*,^†††	7.50 ± 4.47**,^†††	4.64 ± 1.47^††
MDA (nmol/ml)
K	1.38 ± 0.88	4.49 ± 2.05***	4.17 ± 1.62***	2.96 ± 1.34**
V	1.51 ± 0.73	2.17 ± 0.96**,^†††	2.47 ± 0.90***,^†††	2.15 ± 0.78**,^†

Values expressed as mean ± SD. Differences were analyzed with two-tailed tests for non-parametric data: Mann–Whitney U and Wilcoxon tests. P values of <0.05 were considered statistically significant. Patients were divided into two groups: group K, n = 17 (blood collected from a drainage tube placed in the operated knee), and group V, n = 15 (blood collected from a antecubital vein).

GSH, reduced glutathione; GSSG, oxidized glutathione; [2GSSG/(GSH + 2GSSG)] × 100: oxidized glutathione/total glutathione ratio, and expressed as a percentage; MDA, malondialdehyde.

Time course study: before surgery (T₀) and after tourniquet deflation at different times: 3, 10 and 60 minutes (T₁, T₂, and T₃, respectively).

Statistical differences were observed in the same group (T₀ vs. T₁ or T₂ or T₃):

*P < 0.05; **P < 0.01; ***P < 0.001.

Statistical differences were observed between both groups (K vs. R at all times):

^†P < 0.05; ^††P < 0.01; ^†††P < 0.001.

Table 3. Time course of metabolic parameter and myoglobin in blood

Times	T0	T1	T2	T3
pH
K	7.39 ± 0.03	7.33 ± 0.06**	7.30 ± 0.06***	7.31 ± 0.08**
V	7.38 ± 0.04	7.37 ± 0.04*	7.35 ± 0.04**,^††	7.35 ± 0.02***,^†
BE (mmol/l)
K	2.54 ± 2.0	−4.11 ± 2.68***	−3.50 ± 4.0***	−3.02 ± 2.52***
V	2.43 ± 1.89	−1.18 ± 1.34***,^†††	−1.23 ± 1.51***,^†	−0.99 ± 1.41***,^†
HCO3^− (mmol/l)
K	26.9 ± 2.16	21.1 ± 2.65***	21.6 ± 3.23***	23.4 ± 2.38***
V	26.69 ± 2.03	24.2 ± 1.49***,^†††	23.9 ± 0.82***,^†	4.7 ± 1.08**
Lactate (mmol/ml)
K	1.44 ± 0.43	3.28 ± 0.99***	3.24 ± 0.92***	3.10 ± 0.81***
V	1.38 ± 0.38	1.82 ± 0.27***,^†††	1.86 ± 0.34***,^†††	1.66 ± 0.33**,^†††
Myoglobin (ng/ml)
K	37.1 ± 15.2			262.2 ± 148.1***
V	35.7 ± 12.4			167.9 ± 75.6***,^†

Values expressed as mean ± SD. Differences were analyzed with two-tailed tests for non-parametric data: Mann–Whitney U and Wilcoxon tests. P values of <0.05 were considered statistically significant. Patients were divided into two groups: group K, n = 17 (blood collected from a drainage tube placed in the operated knee), and group V, n = 15 (blood collected from the antecubital vein).

BE, base excess; HCO₃⁻, bicarbonate ion.

Time course study: before surgery (T₀) and after tourniquet deflation at different times: 3, 10, and 60 minutes (T₁, T₂, and T₃, respectively).

Statistical differences were observed in the same group (T₀ vs. T₁ or T₂ or T₃):

*P < 0.05; **P < 0.01; ***P < 0.001.

Statistical differences were observed between both groups (K vs. V at all times):

^†P < 0.05; ^††P < 0.01; ^†††P < 0.001.