Klimscha Walter, Ullrich Roman, Nasel Christian, Dietrich Wolfgang, Illievich Udo M, Wildling Eckart, Tschernko Edda, Weidekamm Claudia, Adler Leopold, Heikenwälder Georg, Horvath Gyongyi, Sladen Robert N
Department of Clinical Anesthesia and Intensive Care A, University of Vienna, Austria.
Anesthesiology. 2003 Oct;99(4):834-40. doi: 10.1097/00000542-200310000-00014.
Cerebrovascular carbon dioxide reactivity during high-dose remifentanil infusion was investigated in volunteers by measurement of regional cerebral blood flow (rCBF) and mean CBF velocity (CBFv).
Ten healthy male volunteers with a laryngeal mask for artificial ventilation received remifentanil at an infusion rate of 2 and 4 microg x kg-1 x min-1 under normocapnia, hypocapnia, and hypercapnia. Stable xenon-enhanced computed tomography and transcranial Doppler ultrasonography of the left middle cerebral artery were used to assess rCBF and mean CBFv, respectively. If required, blood pressure was maintained within baseline values with intravenous phenylephrine to avoid confounding effects of altered hemodynamics.
Hemodynamic parameters were maintained constant over time. Remifentanil infusion at 2 and 4 microg x kg-1 x min-1 significantly decreased rCBF and mean CBFv. Both rCBF and mean CBFv increased as the arterial carbon dioxide tension increased from hypocapnia to hypercapnia, indicating that cerebrovascular reactivity remained intact. The average slopes of rCBF reactivity were 0.56 +/- 0.27 and 0.49 +/- 0.28 ml. 100 g-1 x min-1 x mmHg-1 for 2 and 4 microg x kg-1 x min-1 remifentanil, respectively (relative change in percent/mmHg: 1.9 +/- 0.8 and 1.6 +/- 0.5, respectively). The average slopes for mean CBFv reactivity were 1.61 +/- 0.95 and 1.54 +/- 0.83 cm x s-1 x mmHg-1 for 2 and 4 microg x kg-1 x min-1 remifentanil, respectively (relative change in percent/mmHg: 1.86 +/- 0.59 and 1.79 +/- 0.59, respectively). Preanesthesia and postanesthesia values of rCBF and mean CBFv did not differ.
High-dose remifentanil decreases rCBF and mean CBFv without impairing cerebrovascular carbon dioxide reactivity. This, together with its known short duration of action, makes remifentanil a useful agent in the intensive care unit when sedation that can be titrated rapidly is required.
通过测量局部脑血流量（rCBF）和平均脑血流速度（CBFv），在志愿者中研究了大剂量瑞芬太尼输注期间的脑血管二氧化碳反应性。
10名使用喉罩进行人工通气的健康男性志愿者，在正常碳酸血症、低碳酸血症和高碳酸血症状态下，分别以2和4μg·kg⁻¹·min⁻¹的输注速率接受瑞芬太尼。分别使用稳定的氙增强计算机断层扫描和经颅多普勒超声检查左侧大脑中动脉，以评估rCBF和平均CBFv。如有需要，通过静脉注射去氧肾上腺素将血压维持在基线值以内，以避免血流动力学改变的混杂效应。
血流动力学参数随时间保持恒定。以2和4μg·kg⁻¹·min⁻¹的速率输注瑞芬太尼可显著降低rCBF和平均CBFv。随着动脉二氧化碳张力从低碳酸血症增加至高碳酸血症，rCBF和平均CBFv均增加，表明脑血管反应性保持完整。2和4μg·kg⁻¹·min⁻¹瑞芬太尼时，rCBF反应性的平均斜率分别为0.56±0.27和0.49±0.28ml·100g⁻¹·min⁻¹·mmHg⁻¹（百分比/mmHg的相对变化分别为1.9±0.8和1.6±0.5）。2和4μg·kg⁻¹·min⁻¹瑞芬太尼时，平均CBFv反应性的平均斜率分别为1.61±0.95和1.54±0.83cm·s⁻¹·mmHg⁻¹（百分比/mmHg的相对变化分别为1.86±0.59和1.79±0.59）。rCBF和平均CBFv的麻醉前和麻醉后值无差异。
大剂量瑞芬太尼可降低rCBF和平均CBFv，而不损害脑血管二氧化碳反应性。这与其已知的短作用时间一起，使瑞芬太尼在需要快速滴定镇静的重症监护病房中成为一种有用的药物。
