Marini C P, Nathan I M, Efron J, Cohen J R
Department of Surgery, Long Island Jewish Medical Center, New Hyde Park, New York 11042, USA.
J Surg Res. 1997 Jun;70(1):61-5. doi: 10.1006/jsre.1997.5087.
When sodium nitroprusside (SNP) is used to control proximal blood pressure (Px-BP) during cross-clamping (AXC) of the thoracic aorta, it decreases spinal cord perfusion pressure (SCPP) by reducing distal aortic pressure (Ds-BP) and increasing cerebrospinal fluid pressure (CSFP). The decrease cannot be reversed by CSF drainage (CSFD) because such drainage is limited by a reduction in compliance of the spinal canal. Nitroglycerin can also be used to control Px-BP, but its effect on CSF dynamics has not previously been investigated. In the present study we have compared the effects of NTG alone and in combination with CSFD, with SNP and CSFD. Each group (Gp) of six dogs was treated with SNP + CSFD (Gp 1), NTG alone (Gp 2), and NTG + CSFD (Gp 3). Left carotid and right femoral arteries were catheterized to monitor Px-BP and Ds-BP, respectively. CSFP was monitored and CSF was drained through a spinal needle placed in the cisterna cerebellomedullaris. The thoracic aorta was cross-clamped via a left thoracotomy for 60 min. Data were acquired at baseline, during aortic occlusion, and 24 hr after surgery. There were no significant differences in any measurements among the three groups before AXC; after AXC, Px-BP was maintained between 85 and 95 mm Hg in all groups. Ds-BP was significantly lower in Gp 1 than Gp 2 and 3 (7 +/- 2 mm Hg vs. 13 +/- 3 mm Hg and 17 +/- 2 mm Hg, respectively P < 0.05). CSFP did not differ between Gp 1 and 2 (10 +/- 3 mm Hg vs. 9 +/- 1 mm Hg, P > 0.05). CSFD effectively kept CSFP at zero values in Gp 3 during AXC, but not in Gp 1. SCPP was significantly higher in Gp 3 than in Gp 1 and 2 (17 +/- 2 mm Hg vs -3 +/- 4 mm Hg and 4 +/- 1 mm Hg, respectively, P < 0.05). All animals in Gp 1 and 2 suffered paraplegia, as opposed to none in Gp 3. NTG causes paraplegia by decreasing SCPP. When used in conjunction with CSFD, it controls Px-BP without causing paraplegia. CSFD cannot counteract the negative effects of SNP on SCPP; therefore, SNP contributes to postoperative paraplegia. The effects of NTG on cerebrospinal fluid dynamics are different from those of SNP. We caution surgeons against the use of NTG without CSFD during aortic cross-clamping.
当使用硝普钠（SNP）在胸主动脉交叉钳夹（AXC）期间控制近端血压（Px - BP）时，它会通过降低远端主动脉压（Ds - BP）和增加脑脊液压力（CSFP）来降低脊髓灌注压（SCPP）。脑脊液引流（CSFD）无法逆转这种降低，因为这种引流受到椎管顺应性降低的限制。硝酸甘油也可用于控制Px - BP，但此前尚未研究过其对脑脊液动力学的影响。在本研究中，我们比较了单独使用硝酸甘油以及与CSFD联合使用时，与SNP和CSFD的效果。每组6只狗分别接受SNP + CSFD（第1组）、单独使用硝酸甘油（第2组）和硝酸甘油 + CSFD（第3组）治疗。分别插入左颈动脉和右股动脉导管以监测Px - BP和Ds - BP。监测CSFP，并通过置于小脑延髓池的脊髓针引流脑脊液。通过左胸切口对胸主动脉进行交叉钳夹60分钟。在基线、主动脉阻断期间和手术后24小时采集数据。AXC前三组之间的任何测量值均无显著差异；AXC后，所有组的Px - BP维持在85至95 mmHg之间。第1组的Ds - BP显著低于第2组和第3组（分别为7±2 mmHg vs. 13±3 mmHg和17±2 mmHg，P < 0.05）。第1组和第2组之间的CSFP无差异（10±3 mmHg vs. 9±1 mmHg，P > 0.05）。在AXC期间，CSFD有效地使第3组的CSFP保持在零值，但第1组则不然。第3组的SCPP显著高于第1组和第2组（分别为17±2 mmHg vs. - 3±4 mmHg和4±1 mmHg，P < 0.05）。第1组和第2组的所有动物均发生截瘫，而第3组无一只发生。硝酸甘油通过降低SCPP导致截瘫。与CSFD联合使用时，它可控制Px - BP而不引起截瘫。CSFD无法抵消SNP对SCPP的负面影响；因此，SNP会导致术后截瘫。硝酸甘油对脑脊液动力学的影响与SNP不同。我们提醒外科医生在主动脉交叉钳夹期间不要在没有CSFD的情况下使用硝酸甘油。
