George Ronald B, Boyd Colin, McKeen Dolores, Abdo Islam Saleh, Lehmann Christian
Department of Women's and Obstetric Anesthesia, IWK Health Centre, Halifax, NS, Canada.
Department of Anesthesia, Pain Management, and Perioperative Medicine, Dalhousie University, Halifax, NS, Canada.
J Clin Med Res. 2019 Aug;11(8):543-549. doi: 10.14740/jocmr3778. Epub 2019 Jul 27.
This study was a proof of concept of a novel means to evaluate microcirculatory changes during spinal anesthesia for cesarean delivery. It sought to examine the distributive circulatory effects of spinal anesthesia and evaluate the impact of phenylephrine administration on the microcirculation of these women.
After Research Ethics Board approval, healthy, non-laboring pregnant women with singleton, term pregnancies scheduled for elective cesarean delivery were recruited. Participants were randomly assigned to receive either phenylephrine infusion or phenylephrine bolus. Spinal anesthesia was standardized. A sidestream dark-field (SDF) MicroScan video microscope was applied to the sublingual mucosa to obtain microcirculation videos in five different visual fields. Videos were made before and after spinal anesthesia. The resultant videos were analyzed randomly and blindly. The mean microvascular flow index (MFI) values were compared before and after spinal anesthesia. The difference in MFI following spinal anesthesia was compared between phenylephrine infusion and bolus groups.
Thirty-two patients were recruited for the study; 22 patients had complete video sets for analysis. Baseline characteristics were similar between the two groups, including preoperative hemodynamics. There were no significant differences between pre- and post-spinal MFI. The post-spinal MFI within the infusion group (mean ± standard deviation: 2.74 ± 0.21) was not significantly different from the bolus group (2.56 ± 0.42, P = 0.22).
Despite theoretical physiological implications of spinal anesthesia and phenylephrine on the microcirculation, significant alteration of the MFI was not observed between pre- and post-spinal anesthesia (within group). Additionally, despite an eight-fold larger phenylephrine dose for continuous infusion prophylaxis used in this group of women, this did not result in a significant alteration of the microcirculation compared to those who received phenylephrine treatment for hypotension (between groups).
本研究是一种用于评估剖宫产脊髓麻醉期间微循环变化的新方法的概念验证。它旨在研究脊髓麻醉对循环分布的影响，并评估去氧肾上腺素给药对这些女性微循环的影响。
经研究伦理委员会批准后，招募了计划进行择期剖宫产的健康、未临产的单胎足月孕妇。参与者被随机分配接受去氧肾上腺素输注或推注。脊髓麻醉标准化。将侧流暗视野（SDF）微血管显微镜应用于舌下黏膜，以在五个不同视野中获取微循环视频。在脊髓麻醉前后拍摄视频。对所得视频进行随机和盲法分析。比较脊髓麻醉前后的平均微血管血流指数（MFI）值。比较去氧肾上腺素输注组和推注组脊髓麻醉后MFI的差异。
32名患者被纳入研究；22名患者有完整的视频集用于分析。两组的基线特征相似，包括术前血流动力学。脊髓麻醉前后的MFI无显著差异。输注组脊髓麻醉后的MFI（平均值±标准差：2.74±0.21）与推注组（2.56±0.42，P=0.22）无显著差异。
尽管脊髓麻醉和去氧肾上腺素对微循环有理论上的生理影响，但在脊髓麻醉前后（组内）未观察到MFI有显著变化。此外，尽管该组女性用于持续输注预防的去氧肾上腺素剂量是用于低血压治疗剂量的八倍，但与接受去氧肾上腺素治疗低血压的患者相比（组间），这并未导致微循环有显著变化。
