Cambria R P, Davison J K, Zannetti S, L'Italien G, Brewster D C, Gertler J P, Moncure A C, LaMuraglia G M, Abbott W M
Division of Vascular Surgery, Massachusetts General Hospital, Boston 02214, USA.
J Vasc Surg. 1997 Feb;25(2):234-41; discussion 241-3. doi: 10.1016/s0741-5214(97)70365-3.
This report summarizes our experience with epidural cooling (EC) to achieve regional spinal cord hypothermia and thereby decrease the risk of spinal cord ischemic injury during the course of descending thoracic aneurysm (TA) and thoracoabdominal aneurysm (TAA) repair.
During the interval July 1993 to Dec. 1995, 70 patients underwent TA (n = 9, 13%) or TAA (n = 61) (type I, 24 [34%], type II, 11 [15%], type III, 26 [37%]) repair using the EC technique. The latter was accomplished by continuous infusion of normal saline (4 degrees C) into a T11-12 epidural catheter; an intrathecal catheter was placed at the L3-4 level for monitoring of cerebrospinal fluid temperature (CSFT) and pressure (CSFP). All operations (one exception, atriofemoral bypass) were performed with the clamp-and-sew technique, and 50% of patients had preservation of intercostal vessels at proximal or distal anastomoses (30%) or by separate inclusion button (20%). Neurologic outcome was compared with a published predictive model for the incidence of neurologic deficits after TAA repair and with a matched (Type IV excluded) consecutive, control group (n = 55) who underwent TAA repair in the period 1990 to 1993 before use of EC.
EC was successful in all patients, with a 1442 +/- 718 ml mean (range, 200 to 3500 ml) volume of infusate; CSFT was reduced to a mean of 24 degrees +/- 3 degrees C during aortic cross-clamping with maintenance of core temperature of 34 degrees +/- 0.8 +/- C. Mean CSFP increased from baseline values of 13 +/- 8 mm Hg to 31 +/- 6 mm Hg during cross-clamp. Seven patients (10%) died within 60 days of surgery, but all survived long enough for evaluation of neurologic deficits. The EC group and control group were well-matched with respect to mean age, incidence of acute presentations/aortic dissection/aneurysm rupture, TAA type distribution, and aortic cross-clamp times. Two lower extremity neurologic deficits (2.9%) were observed in the EC patients and 13 (23%) in the control group (p < 0.0001). Observed and predicted deficits in the EC patients were 2.9% and 20.0% (p = 0.001), and for the control group 23% and 17.8% (p = 0.48). In considering EC and control patients (n = 115), variables associated with postoperative neurologic deficit were prolonged (> 60 min) visceral aortic cross-clamp time (relative risk, 4.4; 95% CI, 1.2 to 16.5; p = 0.02) and lack of epidural cooling (relative risk, 9.8; 95% CI, 2 to 48; p = 0.005).
EC is a safe and effective technique to increase the ischemic tolerance of the spinal cord during TA or TAA repair. When used in conjunction with a clamp-and-sew technique and a strategy of selective intercostal reanastomosis, EC has significantly reduced the incidence of neurologic deficits after TAA repair.
本报告总结了我们采用硬膜外冷却（EC）实现局部脊髓低温，从而降低降主动脉瘤（TA）和胸腹主动脉瘤（TAA）修复过程中脊髓缺血性损伤风险的经验。
在1993年7月至1995年12月期间，70例患者接受了TA（n = 9，13%）或TAA（n = 61）（I型，24例[34%]；II型，11例[15%]；III型，26例[37%]）修复，采用了EC技术。后者通过将生理盐水（4℃）持续输注到T11 - 12硬膜外导管来实现；在L3 - 4水平放置鞘内导管以监测脑脊液温度（CSFT）和压力（CSFP）。所有手术（1例例外，采用心房股动脉旁路术）均采用钳夹缝合技术，50%的患者在近端或远端吻合处（30%）或通过单独的包裹纽扣（20%）保留肋间血管。将神经学结果与已发表的TAA修复后神经功能缺损发生率预测模型以及1990年至1993年在使用EC之前接受TAA修复的匹配（排除IV型）连续对照组（n = 55）进行比较。
EC在所有患者中均成功，平均输注量为1442±718 ml（范围，200至3500 ml）；在主动脉交叉钳夹期间，CSFT降至平均24℃±3℃，同时维持核心体温为34℃±0.8℃。交叉钳夹期间，平均CSFP从基线值13±8 mmHg升至31±6 mmHg。7例患者（10%）在术后60天内死亡，但均存活足够长时间以评估神经功能缺损。EC组和对照组在平均年龄、急性表现/主动脉夹层/动脉瘤破裂发生率、TAA类型分布以及主动脉交叉钳夹时间方面匹配良好。EC患者中观察到2例下肢神经功能缺损（2.9%），对照组中有13例（23%）（p < 0.0001）。EC患者中观察到的和预测的缺损率分别为2.9%和20.0%（p = 0.001），对照组分别为23%和17.8%（p = 0.48）。在考虑EC组和对照组患者（n = 115）时，与术后神经功能缺损相关的变量为内脏主动脉交叉钳夹时间延长（> 60分钟）（相对风险，4.4；95% CI，1.2至16.5；p = 0.02）和未进行硬膜外冷却（相对风险，9.8；95% CI，2至48；p = 0.005）。
EC是一种在TA或TAA修复过程中提高脊髓缺血耐受性的安全有效技术。当与钳夹缝合技术和选择性肋间血管再吻合策略联合使用时，EC显著降低了TAA修复后神经功能缺损的发生率。
