The Possible Pathophysiological Outcomes and Mechanisms of Tourniquet-Induced Ischemia-Reperfusion Injury during Total Knee Arthroplasty

Table 3

Effects of TQ-induced I/R injury on remote organs.

Sample size/age	TQ pressure/ischemia time	Main findings (compared to baseline level)		Interpretation	References
		Outcomes on remote organ	Systemic effects
/70 ± 4 yr	91 ± 11 min, N/A	Heart: ↔ CPK-MB; ↔ Troponin I	↑ serum MDA	No cardiac muscle injury after TKA with TQ	[31]
/71 ± 7 yr	N/A	Brain: ↔ rScO2; No POCD at 1 week; Lungs: ↔ PF ratio; Kidney: ↔ serum Cr	↑ plasma lactate; ↑ serum CPK; ↔ serum LDH, AST; ↔ serum IL-6, TNF-α, IL-10; ↓ serum TNF-β	No adverse effects on regional cerebral oxygenation, pulmonary oxygenation, and renal function after TKA with TQ	[32]
/67 ± 10 yr	250 mmHg, 52 ± 11 min	Lungs: ↔ urine desmosine/Cr ratio	↑ serum IL-6, TNF-α, CRP, and WBC count	No lung injury occurred as indicated by the unaltered marker of elastin breakdown after TKA with TQ	[33]
/64–73 yr	300–350 mmHg, 83–121 min	Kidney: ↑ urine α-1-microglobulin/Cr ratio; ↑ urine GST-α/Cr ratio; ↔ urine NAG/Cr ratio; ↓ serum cystatin C; ↓ serum Cr and urea	↑ plasma lactate; ↑ serum myoglobin; ↑ serum lactoferrin	Possible proximal tubular injury after TKA with TQ	[30]

AST: aspartate aminotransferase; CPK: creatinine phosphokinase; CRP: c-reactive protein; Cr: creatinine; GST-α: glutathione-S-transferase-α; IL: interleukin; LDH: lactate dehydrogenase; MDA: malondialdehyde; N/A: not available; NAG: N-acetyl-β-D-glucosaminidase; PF ratio: ratio of arterial oxygen partial pressure to fractional inspired oxygen; POCD: postoperative cognitive dysfunction; rScO₂: regional cerebral oxygen saturation; TKA: total knee arthroplasty; TNF: tumor necrosis factor; TQ: tourniquet; WBC: white blood cell.