Bigam D L, Barrington K J, Jirsch D W, Cheung P Y
Department of Pediatrics, University of Alberta, Edmonton, Canada.
Biol Neonate. 1998;73(3):198-206. doi: 10.1159/000013978.
To determine the effects of a continuous epinephrine infusion on renal and mesenteric blood flow in both healthy newborn piglets and animals subjected to hemorrhagic shock.
Superior mesenteric artery (SMA) and left renal artery ultrasonic flow probes were implanted into 16 1- to 3-day-old piglets. Two days later, the effects of epinephrine on SMA and renal blood flow, mean arterial pressure (MAP) and central venous pressure were measured in conscious, non-sedated normovolemic piglets. Epinephrine doses of 0.2, 0.4, 0.8, 1.6 and 3.2 microg/kg.min were used in random order. Piglets were subsequently hemorrhaged (20 ml/kg) to mild hypotension and again received epinephrine infusion in the same doses.
Doses of epinephrine less than 3.2 microg/kg.min had no significant effects on renal or mesenteric arterial flow. At 3.2 microg/kg.min of epinephrine during normovolemia, there was a significant decrease in SMA blood flow (34% [SD 42], p < 0.05) and increase in SMA vascular resistance (147% [SD 114], p < 0.05). Similar results were shown during hypovolemia, SMA flow decreased by 32% (SD 33), and SMA vascular resistance increased by 220.3% (SD 177). At 3.2 microg/kg.min renal artery flow decreased by 43% (SD 21) during normovolemia and a similar decrease occurred during hypovolemia, 37% (SD 31). Renal vascular resistance increased by about 200% at this dose (normovolemia 211% [SD 185], hypovolemia 186% [SD 150], p < 0.01). Low-to-moderate dose epinephrine caused no significant change in SMA or renal blood flow. During hypovolemia low dose epinephrine infusion was associated with a trend to increased SMA blood flow.
Low-dose epinephrine does not cause vasoconstriction in the renal or mesenteric circulations during normovolemia or hypovolemia. High doses of epinephrine above 1.6 microg/kg.min may cause renal or mesenteric ischemia, in either the normovolemic or hypovolemic neonate.
确定持续输注肾上腺素对健康新生仔猪和失血性休克动物肾血流及肠系膜血流的影响。
将肠系膜上动脉（SMA）和左肾动脉超声血流探头植入16只1至3日龄的仔猪体内。两天后，在清醒、未镇静的血容量正常的仔猪中测量肾上腺素对SMA和肾血流、平均动脉压（MAP）及中心静脉压的影响。按随机顺序使用0.2、0.4、0.8、1.6和3.2微克/千克·分钟的肾上腺素剂量。随后仔猪失血（20毫升/千克）至轻度低血压，再次以相同剂量输注肾上腺素。
低于3.2微克/千克·分钟的肾上腺素剂量对肾或肠系膜动脉血流无显著影响。在血容量正常时，肾上腺素剂量为3.2微克/千克·分钟时，SMA血流显著减少（34%[标准差42]，p<0.05），SMA血管阻力增加（147%[标准差114]，p<0.05）。在低血容量时也出现类似结果，SMA血流减少32%（标准差33），SMA血管阻力增加220.3%（标准差177）。在血容量正常时，肾上腺素剂量为3.2微克/千克·分钟时肾动脉血流减少43%（标准差21），在低血容量时也有类似减少，为37%（标准差31）。在此剂量下肾血管阻力增加约200%（血容量正常时为211%[标准差185]，低血容量时为186%[标准差150]，p<0.01）。低至中等剂量的肾上腺素对SMA或肾血流无显著影响。在低血容量时，低剂量肾上腺素输注与SMA血流增加趋势相关。
在血容量正常或低血容量时，低剂量肾上腺素不会引起肾或肠系膜循环血管收缩。在血容量正常或低血容量的新生儿中，高于1.6微克/千克·分钟的高剂量肾上腺素可能导致肾或肠系膜缺血。
