腰麻患者骨科手术中气囊止血带放气时机的选择及其对循环稳定性和术后认知功能的影响

Timing of Tourniquet Deflation in Orthopedic Surgery under Spinal Anesthesia and Its Impact on Circulatory Stability and Postoperative Cognitive Function

摘要: 目的：探讨腰麻下骨科手术患者气囊止血带的最佳放气时机，分析不同放气策略对围术期循环稳定性及术后认知功能的影响机制。方法：选取2024年1月至2025年6月在我院行单侧下肢骨科手术(含关节置换、骨折复位固定)的腰麻患者120例，ASA分级I~II级，年龄45~75岁。采用随机数字表法分为三组，每组40例：A组(即时放气组)于手术结束后即刻完全放气；B组(延迟放气组)手术结束后维持止血带充气状态，待伤口缝合完毕后5~10分钟放气；C组(分次放气组)手术结束后先将止血带的压力降至患肢收缩压 + 50 mmHg，维持5分钟后再完全放气。记录三组患者放气前(T0)、放气后5分钟(T1)、15分钟(T2)、30分钟(T3)的平均动脉压(MAP)、心率(HR)及中心静脉压(CVP)；采用简易精神状态量表(MMSE)评估术前1天、术后1天、3天、7天的认知功能；检测术前及术后24小时血清炎症因子(IL-1β, IL-6, TNF-α)水平；记录术后认知功能障碍(POCD)发生率及不良事件(低血压、高钾血症等)发生情况。结果：循环稳定性方面：A组T1时刻MAP较T0显著下降[(78.3 ± 6.5) mmHg vs (92.5 ± 7.2) mmHg]，HR显著增快[(98.6 ± 8.3)次/分vs (76.2 ± 6.8)次/分]，波动幅度均大于B、C两组(P < 0.05)；C组T1-T3时刻MAP、HR及CVP波动幅度最小，维持在安全范围(P > 0.05)。认知功能方面：术后1天、3天A组MMSE评分显著低于B、C两组[(23.5 ± 2.1)分vs (26.3 ± 1.8)分、(27.1 ± 1.6)分，P < 0.05]；A组POCD发生率为27.5% (11/40)，显著高于B组12.5% (5/40)及C组7.5% (3/40) (P < 0.05)。炎症因子水平：A组术后24小时IL-1β、IL-6、TNF-α水平均显著高于B、C两组[(8.3 ± 1.5) pg/mL vs (5.7 ± 1.2) pg/mL, (4.9 ± 1.1) pg/mL, P < 0.05]。不良事件：A组低血压发生率 15.0% (6/40)，显著高于B组5.0% (2/40)及C组2.5% (1/40) (P < 0.05)，三组均未发生严重高钾血症及神经损伤。结论：腰麻下骨科手术患者采用气囊止血带分次放气策略(先放气至患肢收缩压 + 50 mmHg，间隔5分钟后完全放气)，可有效减轻循环波动，降低炎症因子释放，减少POCD发生率，是兼顾安全性与有效性的最优放气时机选择。

Abstract: Objective: To investigate the optimal timing of tourniquet deflation in patients undergoing orthopedic surgery under spinal anesthesia, and to analyze the mechanisms by which different deflation strategies impact perioperative hemodynamic stability and postoperative cognitive function. Methods: This study included 120 patients who underwent unilateral lower limb orthopedic surgery (including joint replacement, fracture reduction, and internal fixation) under spinal anesthesia in the First Affiliated Hospital of Naval Medical University from January 2024 to June 2025. The patients, with an ASA physical status class of I-II and aged 45-75 years, were randomly assigned into three groups using a random number table method (n=40 each). In group A (Immediate Deflation), the tourniquet was completely deflated immediately when the surgery was completed. In group B (Delayed Deflation), the tourniquet remained inflated after surgery and was deflated 5 - 10 minutes after wound closure was finished. In group C (Staged Deflation), the tourniquet pressure was first reduced to the patient’s limb systolic blood pressure plus 50 mmHg after surgery, maintained for 5 minutes, and then completely deflated. The following parameters were recorded for all three groups: mean arterial pressure (MAP), heart rate (HR), and central venous pressure (CVP) at baseline before deflation (T0), and at 5 (T1), 15 (T2), and 30 (T3) minutes after deflation. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) on the preoperative day 1, and postoperative days 1, 3, and 7. Serum levels of inflammatory cytokines (IL-1β, IL-6, TNF-α) were measured preoperatively and 24 hours postoperatively. Besides, the incidence of postoperative cognitive dysfunction (POCD) and adverse events such as hypotension and hyperkalemia were also recorded. Results: In hemodynamic stability, the mean arterial pressure (MAP) of Group A (Immediate Deflation Group) at time T1 showed a significant decrease compared to the baseline T0 [(78.3 ± 6.5) mmHg vs. (92.5 ± 7.2) mmHg], and the heart rate (HR) increased significantly [(98.6 ± 8.3) bpm vs. (76.2 ± 6.8) bpm]. The magnitudes of these fluctuations were greater than those observed in Groups B and C (P < 0.05). Meanwhile, patients in Group C (Staged Deflation Group) exhibited the smallest fluctuations in MAP, HR, and central venous pressure (CVP) from T1 to T3, with all parameters remaining within safe ranges (P > 0.05). Regarding cognitive function, the Mini-Mental State Examination (MMSE) scores of Group A on postoperative day 1 and day 3 were significantly lower than those of Groups B and C [(23.5 ± 2.1) points vs. (26.3 ± 1.8) points and (27.1 ± 1.6) points, respectively; P < 0.05]. The incidence of postoperative cognitive dysfunction (POCD) in Group A was 27.5% (11/40), which was significantly higher than the 12.5% (5/40) in Group B and 7.5% (3/40) in Group C (P< 0.05).In inflammatory cytokine levels, the serum concentrations of IL-1β, IL-6, and TNF-α at 24 hours after operation in Group A were significantly higher than those in Groups B and C [ (8.3 ± 1.5) pg/mL vs. (5.7 ± 1.2) pg/mL and (4.9 ± 1.1) pg/mL, respectively; P< 0.05]. Regarding adverse events, the incidence of hypotension in Group A was 15.0% (6/40), significantly higher than the 5.0% (2/40) in Group B and 2.5% (1/40) in Group C (P < 0.05). No severe hyperkalemia or neurological injury occurred in any of the three groups. Conclusion: For patients undergoing orthopedic surgery under anesthesia, the adoption of a staged tourniquet deflation protocol—where the cuff pressure is first reduced to the limb’s systolic blood pressure plus 50 mmHg, followed by complete deflation after a 5-minute interval—can effectively mitigate hemodynamic fluctuations, attenuate the release of inflammatory cytokines, and reduce the incidence of postoperative cognitive dysfunction (POCD). Thus, this protocol represents an optimal deflation strategy that balances safety and efficacy.