Krejci Vladimir, Hiltebrand Luzius B, Sigurdsson Gisli H
Department of Anesthesiology, University of Berne, Inselspital, Berne, Switzerland.
Crit Care Med. 2006 May;34(5):1456-63. doi: 10.1097/01.CCM.0000215834.48023.57.
The use of vasopressors for treatment of hypotension in sepsis may have adverse effects on microcirculatory blood flow in the gastrointestinal tract. The aim of this study was to measure the effects of three vasopressors, commonly used in clinical practice, on microcirculatory blood flow in multiple abdominal organs in sepsis.
Random order, cross-over design.
University laboratory.
Eight sedated and mechanically ventilated pigs.
Pigs were exposed to fecal peritonitis-induced septic shock. Mesenteric artery flow was measured using ultrasound transit time flowmetry. Microcirculatory flow was measured in gastric, jejunal, and colon mucosa; jejunal muscularis; and pancreas, liver, and kidney using multiple-channel laser Doppler flowmetry. Each animal received a continuous intravenous infusion of epinephrine, norepinephrine, and phenylephrine in a dose increasing mean arterial pressure by 20%. The animals were allowed to recover for 60 mins after each drug before the next was started.
During infusion of epinephrine (0.8 +/- 0.2 mug/kg/hr), mean arterial pressure increased from 66 +/- 5 to 83 +/- 5 mm Hg and cardiac index increased by 43 +/- 9%. Norepinephrine (0.7 +/- 0.3 mug/kg/hr) increased mean arterial pressure from 70 +/- 4 to 87 +/- 5 mm Hg and cardiac index by 41 +/- 8%. Both agents caused a significant reduction in superior mesenteric artery flow (11 +/- 4%, p < .05, and 26 +/- 6%, p < .01, respectively) and in microcirculatory blood flow in the jejunal mucosa (21 +/- 5%, p < .01, and 23 +/- 3%, p < .01, respectively) and in the pancreas (16 +/- 3%, p < .05, and 8 +/- 3%, not significant, respectively). Infusion of phenylephrine (3.1 +/- 1.0 mug/kg/min) increased mean arterial pressure from 69 +/- 5 to 85 +/- 6 mm Hg but had no effects on systemic, regional, or microcirculatory flow except for a 30% increase in jejunal muscularis flow (p < .01).
Administration of the vasopressors phenylephrine, epinephrine, and norepinephrine failed to increase microcirculatory blood flow in most abdominal organs despite increased perfusion pressure and-in the case of epinephrine and norepinephrine-increased systemic blood flow. In fact, norepinephrine and epinephrine appeared to divert blood flow away from the mesenteric circulation and decrease microcirculatory blood flow in the jejunal mucosa and pancreas. Phenylephrine, on the other hand, appeared to increase blood pressure without affecting quantitative blood flow or distribution of blood flow.
在脓毒症中使用血管升压药治疗低血压可能会对胃肠道的微循环血流产生不良影响。本研究的目的是测量临床实践中常用的三种血管升压药对脓毒症时多个腹部器官微循环血流的影响。
随机顺序、交叉设计。
大学实验室。
八只镇静并机械通气的猪。
使猪暴露于粪便性腹膜炎诱导的感染性休克。使用超声渡越时间血流仪测量肠系膜动脉血流。使用多通道激光多普勒血流仪测量胃、空肠和结肠黏膜、空肠肌层、胰腺、肝脏和肾脏的微循环血流。每只动物接受持续静脉输注肾上腺素、去甲肾上腺素和去氧肾上腺素，剂量使平均动脉压升高20%。每种药物输注后让动物恢复60分钟再开始下一种药物输注。
在输注肾上腺素（0.8±0.2微克/千克/小时）期间，平均动脉压从66±5毫米汞柱升至83±5毫米汞柱，心脏指数增加43±9%。去甲肾上腺素（0.7±0.3微克/千克/小时）使平均动脉压从70±4毫米汞柱升至87±5毫米汞柱，心脏指数增加41±8%。两种药物均导致肠系膜上动脉血流显著减少（分别为11±4%，p<0.05；26±6%，p<0.01），空肠黏膜微循环血流显著减少（分别为21±5%，p<0.01；23±3%，p<0.01），胰腺微循环血流也减少（分别为16±3%，p<0.05；8±3%，无显著差异）。输注去氧肾上腺素（3.1±1.0微克/千克/分钟）使平均动脉压从69±5毫米汞柱升至85±6毫米汞柱，但除空肠肌层血流增加30%（p<0.0）外，对全身、局部或微循环血流均无影响。
尽管灌注压升高，且肾上腺素和去甲肾上腺素能增加全身血流，但给予血管升压药去氧肾上腺素、肾上腺素和去甲肾上腺素未能增加大多数腹部器官的微循环血流。事实上，去甲肾上腺素和肾上腺素似乎使血流从肠系膜循环分流，减少空肠黏膜和胰腺的微循环血流。另一方面，去氧肾上腺素似乎能升高血压而不影响血流量或血流分布。
