分析全膝关节置换术中使用止血带的压力与术中出血量、收缩压、身体质量指数(BMI)等因素的关系，为提升止血带使用的安全性提供参考。

采用回顾性研究方法，收集2019年1月至2019年12月在广州中医药大学第二附属医院接受择期行初次全膝关节置换术患者的人口学资料、止血带压力、止血带时间、手术时间、术中出血量。纳入已行初次全膝关节置换术患者的数据，排除膝关节单髁置换者及复杂的二次膝关节翻修者。采用(±s)或M(P₂₅，P₇₅)描述数据，应用Spearman’s相关性分析。3组止血带压力8个观察时点：术前1 d测血压(T1)、麻醉前(入手术室第1次)(T2)、麻醉后(T3)、止血带充气前(T4)、止血带充气2 min(T5)、止血带充气10 min(T6)、止血带放气前(T7)、止血带放气10 min(T8)，各时间点血压比较采用秩和检验(Kruskal-Wallis H)。

共纳入475例患者资料，使用止血带压力为250(250，260)mmHg，止血带时间为52(41，62)min，手术时间为96(85，115)min，术中出血量为50(50，50)ml。止血带压力与身体质量指数(BMI)呈正相关关系(r_s＝0.283，P<0.01)。止血带不同压力分组在T2、T4、T5、T7观察时点的收缩压组间差异均有统计学意义(H＝11.077，P＝0.004；H＝19.688，P<0.001；H＝10.326，P＝0.006；H＝9.103，P<0.01)。术中无输血，术后无皮肤及组织压伤、深静脉血栓形成等并发症发生。

BMI与止血带压力呈正相关关系，提示设置止血带压力需考虑患者的BMI。止血带阻断下肢血流后改变了循环系统血液容量的分布，止血带压力水平与术中收缩压的变化有关，医护人员需密切关注患者收缩压的变化。

To analyze the relationship between tourniquet pressure and intraoperative blood loss, systolic pressure, body mass index (BMI) and other factors during total knee arthroplasty (TKA), and to provide reference for improving the safety of tourniquet use.

A retrospective study was conducted on consecutive series of primary TKA in the Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine from January 2019 to December 2019.The patients who had undergone primary total knee replacement were included, those with unicondylar knee replacement and complex secondary knee revision were excluded. Demographic data, tourniquet pressure, tourniquet time, operation time, and intraoperative blood loss were collected. (±s)or M(P₂₅, P₇₅)were used for data description, and Spearman's correlation analysis was used. Rank sum test (Kruskal-Wallis H test) was used for comparison of blood pressure at eight observation time points: blood pressure measured one day before surgery (T1), before anesthesia (the first time in the operating room) (T2), after anesthesia (T3), before tourniquet inflation (T4), tourniquet inflation two minutes (T5), tourniquet inflation 10 min (T6), before tourniquet deflation (T7), tourniquet deflation 10 min (T8).

A total of 475 patients were enrolled. The tourniquet time was 52 (41, 62) min, the operation time was 96 (85, 115) min, and the intraoperative blood loss was 50 (50, 50) ml. There was a positive correlation between tourniquet pressure and body mass index (BMI) (r_s=0.283, P<0.01). The systolic pressure differences among different tourniquet pressure groups were statistically significant at T2, T4, T5 and T7 (H=11.077, P=0.004; H=19.688, P<0.001; H=10.326, P=0.006; H=9.103, P<0.01). There was no intraoperative blood transfusion, no skin or tissue compression injury, deep vein thrombosis, nor other complication occurred after the surgery.

There is a positive correlation between BMI and tourniquet pressure, suggesting that patients' BMI should be considered in setting tourniquet pressure. Tourniquet pressure changed the distribution of blood volume in the circulatory system after the tourniquet blocked lower extremity blood flow, the level of tourniquet pressure is related to the change of systolic pressure during the operation, and attention should be paid to the changes of systolic pressure.