Departments of Paediatrics and Medicine, University of Alberta, Calgary, Alberta, Canada.
Shock. 2010 May;33(5):519-25. doi: 10.1097/SHK.0b013e3181c99727.
Although the use of supplemental oxygen to resuscitate asphyxiated neonates remains controversial, the effects of hypoxia and reoxygenation (room air versus pure oxygen) on the hypothalamo-pituitary-adrenal axis are unknown. We aimed to evaluate the effect of hypoxia and reoxygenation with either 21% or 100% oxygen on plasma cortisol before and after an adrenocorticotrophin (ACTH) challenge in newborn piglets. Thirty-five piglets (aged 1-3 days, weighing 1.5-2.4 kg) were instrumented to measure heart rate, MAP, and cardiac output. After 2 h of normocapnic hypoxia (PaO2, 20-30 mmHg; pH, <6.95), piglets were resuscitated with 21% or 100% oxygen for 1 h and then 21% oxygen for 3 h. Sham-operated piglets had no hypoxia-reoxygenation (H-R). Serial plasma cortisol levels were determined after a blinded randomized administration of ACTH (4 microg/kg, i.v.) or saline at 2 h reoxygenation. The expression of steroidogenic factor 1 in the adrenals was studied. Cardiac output decreased with hypoxia and recovered with resuscitation. Piglets developed hypotension similarly in 21% and 100% H-R groups during reoxygenation (versus sham-operated group, P < 0.05). Both H-R groups had increased plasma cortisol levels (versus sham-operated group, P < 0.05) at 2 h of reoxygenation after hypoxia, with a further increase in levels in 21% H-R piglets at 4 h reoxygenation (versus 100% H-R piglets, P < 0.05). The response to ACTH was delayed in H-R groups, with the maximum increase at 120 min post-ACTH administration (versus 30-60 min post-ACTH for sham-operated piglets). Plasma cortisol levels increased significantly post-ACTH administration in 21% H-R and sham-operated piglets (115% +/-50% and 126% +/- 25% at 120 min, respectively, P < 0.05 vs. pre-ACTH baselines) but not in 100% H-R piglets (51% +/-14%), which had a lower expression of steroidogenic factor 1 than the other groups. Although the clinical significance of high cortisol levels and cortisol response to ACTH in H-R newborn piglets is uncertain, a preserved cortisol response may support using room air in neonatal resuscitation.
虽然用补充氧气来复苏窒息的新生儿仍然存在争议，但是缺氧和再氧合（空气与纯氧）对下丘脑-垂体-肾上腺轴的影响还不清楚。我们的目的是评估在新生仔猪接受促肾上腺皮质激素（ACTH）挑战前后，用 21%或 100%氧气进行缺氧和再氧合对血浆皮质醇的影响。35 头仔猪（1-3 天龄，体重 1.5-2.4 公斤）接受了仪器测量心率、平均动脉压和心输出量。在 2 小时的正常碳酸血症缺氧（PaO2，20-30 mmHg；pH，<6.95）后，仔猪用 21%或 100%氧气复苏 1 小时，然后用 21%氧气复苏 3 小时。假手术组的仔猪没有进行缺氧-再氧合（H-R）。在 2 小时再氧合时，用 4 μg/kg，静脉内）或盐水，进行了盲法随机的 ACTH 给药后，测定了连续的血浆皮质醇水平。研究了肾上腺中的类固醇生成因子 1 的表达。随着缺氧，心输出量降低，并在再氧合时恢复。与假手术组相比，在再氧合期间，21%和 100% H-R 组的仔猪都出现了类似的低血压（P < 0.05）。与假手术组相比，两组 H-R 仔猪在缺氧后 2 小时的血浆皮质醇水平均升高（P < 0.05），在 21% H-R 仔猪的 4 小时再氧合时进一步升高（与 100% H-R 仔猪相比，P < 0.05）。H-R 组对 ACTH 的反应延迟，最大增加发生在 ACTH 给药后 120 分钟（与假手术组的 30-60 分钟相比）。在 21% H-R 和假手术仔猪中，ACTH 给药后血浆皮质醇水平显著升高（分别在 120 分钟时增加 115% +/-50%和 126% +/- 25%，与 ACTH 前基线相比，P < 0.05），但在 100% H-R 仔猪中没有增加（增加 51% +/-14%），这些仔猪的类固醇生成因子 1 的表达低于其他组。尽管 H-R 新生儿中皮质醇水平升高和对 ACTH 的皮质醇反应的临床意义尚不确定，但皮质醇反应的保留可能支持在新生儿复苏中使用空气。
