Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Department of Intensive Care, Austin Hospital, Melbourne, Victoria, Australia; Department of Anaesthesiology and Intensive Care Medicine, Graduate School of Medicine, Osaka University, Japan.
Preclinical Critical Care Unit, Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia; Department of Anesthesiology and Resuscitology, Okayama University Hospital, Okayama, Japan.
Br J Anaesth. 2020 Aug;125(2):192-200. doi: 10.1016/j.bja.2020.03.033. Epub 2020 Jun 18.
Anaesthesia-induced changes in renal perfusion are dependent on the choice of anaesthetic agent. However, the effects of varying inspired oxygen fraction (FiO) on renal perfusion and oxygenation during TIVA (propofol + fentanyl) or volatile anaesthesia (VA; isoflurane) are unknown.
In 16 Merino ewes, we surgically implanted a renal artery flow probe and laser-Doppler and oxygen-sensing probes in the renal medulla and cortex. We compared the systemic and renal effects of graded alterations in FiO (0.21, 0.40, 0.60, and 1.0) during TIVA or VA and compared the changes with those in the non-anaesthetised state.
Compared with the non-anaesthetised state, TIVA and VA decreased renal blood flow (-50% vs -75%), renal oxygen delivery (-50% vs -80%), and renal cortical (-40% vs -60%) and medullary perfusion (-50% vs -75%). At an FiO of 0.21, both anaesthetic regimens induced similar reductions in cortical (-58 vs -65%) and medullary (-37% vs -38%) oxygenation. At higher concentrations of FiO, renal blood flow and renal tissue perfusion were not changed, but intrarenal oxygenation improved similarly under TIVA and VA. In particular, at an FiO of ≥0.40 and ≤0.60, cortical and medullary oxygen tension were similar to the non-anaesthetised state.
Irrespective of FiO, TIVA decreased renal and intrarenal perfusion less than VA, but at low FiO concentrations both led to equivalent reductions in renal cortical and medullary oxygenation. However, with FiO between 0.40 and 0.60 during TIVA or VA, both cortical and medullary oxygenation was maintained at normal physiological levels.
麻醉诱导的肾灌注变化取决于麻醉药物的选择。然而，在 TIVA（丙泊酚+芬太尼）或挥发性麻醉（异氟醚）期间，不同吸入氧分数（FiO）对肾灌注和氧合的影响尚不清楚。
在 16 只美利奴羊中，我们手术植入了肾动脉流量探头以及肾髓质和皮质中的激光多普勒和氧敏探头。我们比较了 TIVA 或 VA 期间 FiO（0.21、0.40、0.60 和 1.0）分级变化对全身和肾脏的影响，并将其与非麻醉状态下的变化进行了比较。
与非麻醉状态相比，TIVA 和 VA 降低了肾血流量（-50%对-75%）、肾氧输送（-50%对-80%）以及肾皮质（-40%对-60%）和髓质灌注（-50%对-75%）。在 FiO 为 0.21 时，两种麻醉方案均导致皮质（-58%对-65%）和髓质（-37%对-38%）氧合的相似降低。在较高 FiO 浓度下，肾血流量和肾组织灌注没有改变，但 TIVA 和 VA 下肾内氧合同样得到改善。特别是在 FiO 为≥0.40 和≤0.60 时，皮质和髓质氧分压与非麻醉状态相似。
无论 FiO 如何，TIVA 引起的肾和肾内灌注减少均少于 VA，但在低 FiO 浓度下，两者均导致肾皮质和髓质氧合的等效降低。然而，在 TIVA 或 VA 期间 FiO 在 0.40 至 0.60 之间，皮质和髓质氧合均维持在正常生理水平。
