Etz Christian D, Di Luozzo Gabriele, Zoli Stefano, Lazala Ricardo, Plestis Konstadinos A, Bodian Carol A, Griepp Randall B
Department of Cardiothoracic Surgery, Mount Sinai School of Medicine, New York, New York 10029, USA.
Ann Thorac Surg. 2009 Jun;87(6):1764-73; discussion 1773-4. doi: 10.1016/j.athoracsur.2009.02.101.
Although maintenance of adequate spinal cord perfusion pressure (SCPP) by the paraspinal collateral network is critical to the success of surgical and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms, direct monitoring of SCPP has not previously been described.
A catheter was inserted into the distal end of a ligated thoracic segmental artery (SA) (T6 to L1) in 13 patients, 7 of whom underwent descending thoracic and thoracoabdominal aortic aneurysm repair using deep hypothermic circulatory arrest. Spinal cord perfusion pressure was recorded from this catheter before, during, and after serial SA sacrifice, in pairs, from T3 through L4, at 32 degrees C. Somatosensory and motor evoked potentials were also monitored during SA sacrifice and until 1 hour after cardiopulmonary bypass. Target mean arterial pressure was 90 mm Hg during SA sacrifice and after nonpulsatile cardiopulmonary bypass, and 60 mm Hg during cardiopulmonary bypass.
A mean of 9.8 +/- 2.6 SAs were sacrificed without somatosensory and motor evoked potential loss. Spinal cord perfusion pressure fell from 62 +/- 12 mm Hg (76% +/- 11% of mean arterial pressure) before SA sacrifice to 53 +/- 13 mm Hg (58% +/- 15% of mean arterial pressure) after SA clamping. The most significant drop occurred with initiation of nonpulsatile cardiopulmonary bypass, reaching 29 +/- 11 mm Hg (46% +/- 18% of mean arterial pressure) before deep hypothermic circulatory arrest. Spinal cord perfusion pressure recovered during rewarming to 40 +/- 14 mm Hg (51% +/- 20% of mean arterial pressure), and further within the first hour of reestablished pulsatile flow. Somatosensory and motor evoked potentials returned in all patients intraoperatively. Recovery of SCPP began intraoperatively, and in 5 patients with prolonged monitoring, continued during the first 24 hours postoperatively. All but 1 patient, who had remarkably low postoperative SCPPs and experienced paraparesis, regained normal spinal cord function.
This study supports experimental data showing that SCPP drops markedly but then recovers gradually during the first several hours after extensive SA sacrifice. Direct monitoring may help prevent a fall of SCPP below levels critical for spinal cord recovery after surgery and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms.
尽管椎旁侧支循环维持足够的脊髓灌注压（SCPP）对于降主动脉和胸腹主动脉瘤的手术及血管内修复的成功至关重要，但此前尚未描述过对SCPP的直接监测。
将一根导管插入13例患者结扎的胸段节段动脉（SA）（T6至L1）远端，其中7例患者在深低温循环停搏下行降主动脉和胸腹主动脉瘤修复术。在32℃时，从该导管记录在依次成对牺牲T3至L4节段动脉之前、期间和之后的脊髓灌注压。在牺牲节段动脉期间及体外循环后1小时内，还监测体感诱发电位和运动诱发电位。在牺牲节段动脉期间及非搏动性体外循环后，目标平均动脉压为90mmHg，体外循环期间为60mmHg。
平均牺牲9.8±2.6条节段动脉，未出现体感诱发电位和运动诱发电位丧失。脊髓灌注压从牺牲节段动脉前的62±12mmHg（平均动脉压的76%±11%）降至夹闭节段动脉后的53±13mmHg（平均动脉压的58%±15%）。最显著的下降发生在开始非搏动性体外循环时，在深低温循环停搏前降至29±11mmHg（平均动脉压的46%±18%）。复温过程中脊髓灌注压恢复至40±14mmHg（平均动脉压的51%±20%），在恢复搏动性血流的第一小时内进一步恢复。所有患者术中体感诱发电位和运动诱发电位均恢复。SCPP的恢复在术中开始，在5例进行长时间监测的患者中，术后24小时内持续恢复。除1例术后SCPP极低且出现轻瘫的患者外，所有患者脊髓功能均恢复正常。
本研究支持实验数据，表明在广泛牺牲节段动脉后的最初数小时内，SCPP显著下降，但随后逐渐恢复。直接监测可能有助于防止SCPP降至低于降主动脉和胸腹主动脉瘤手术及血管内修复后脊髓恢复所需的关键水平。
