脊麻前经静脉预注晶体／胶体混合液或单纯晶体液对老年患者心输出量和每搏量的影响

背景低血压是脊髓麻醉后最常见的心血管反应。我们选择行经尿道前列腺切除手术的老年患者作为研究对象，在脊髓麻醉前预注晶体／胶体混合液或单纯晶体液，观察其心输出量变化。方法60例男性患者，ASAⅠ-Ⅲ，随机分为3组。脊髓麻醉前20分钟内，对照组不给予任何预注；生理盐水组给予500rnl生理盐水；羟乙基淀粉组（HES）给予生理盐水500ml和6％HES130／0．4500ml。监测平均动脉压（MAP）、心率，并应用胸部电生物阻抗法监测心输出量和每搏量。结果对照组的MAP从基线水平明显下降（从104±20rnmHg到88±11mmHg[P：0．005]），并且显著低于HES组（从107±13mmHg到97±12mmHg[P=0．001]）。但生理盐水组与对照组、HES组相比，MAP的降低没有显著性差异（103±14ml／1Hg到92±17mmHg）。对照组的C0下降明显（从4．9±1．6L／min到3．8±0．9L／min[P=0．002]），并低于HES组，后者预注后，CO明显增加（从5．2±1．23L／min到6．2±1．43L／min[P=0．003]），直到手术结束时仍维持在基线水平。结论经静脉预先给予生理盐水及HES虽然可以预防心输出量的降低，但是不能防止行前列腺切除手术的老年患者出现脊麻后低血压。

BACKGROUND： Hypotension is the most common cardiovascular response to spinal anesthesia. We com- pared the effects of crystalloid/col/oid versus crystalloid administration before spinal anesthesia on cardiac output （CO） in eld- erly patients undergoing transurethral resection of the prostate. METHODS： Sixty male ASA Ⅰ-Ⅲ patients were randomized to one of three groups the control group received no intravascular volume preload, the saline group received 500 ml saline, and the hydroxyethyl starch （tIES） group received 500 ml of saline plus 500 ml of 6% lIES 130/0.4 within 20 rnin before spinal anesthesia. Mean arterial blood pressure （MAP） and heart rate, CO, and stroke volume were recorded with a thoracic electrical bioimpedance device. RESULTS： MAP significantly decreased from baseline in the control group （from 104 ±20 mmHg to 88 ± 11 mm Hg [P =0. 005 ] ） and was significantly lower than in the HES group （from 107 ± 13 mm Hg to 97 ±12 mm Hg [P=0.001 ]）. In the saline group, MAP decreased （103 ± 14 mm Hg to 92 ± 17 mm Hg） with no significant differences compared with the control and lIES groups. CO decreased significantly in the control group （from 4.9 ±1. 6 L/min to 3.8 ±0. 9 L/rain [ P = 0. 002 ] ）anti was significantly lower than in the lIES patients in whom CO increased significantly after volume preload （from 5.2 ± 1.23 L/rain to 6. 2 ± 1. 43 L/min [ P = 0.003 ] ） and remained at baseline level until the end of the study. CONCLUSIONS： Intravascular volume preload with saline plus HES prevented a decrease of CO, but did not pre- vent spinal anesthesia-induced hypotension in elderly patients undergoing transurethral resection of the prostate.