Journal Article10.1097/00000542-198902000-00016
Phenylephrine Increases Regional Cerebral Blood Flow Following Hemorrhage during Isoflurane–Oxygen Anesthesia
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TL;DR: Using the radioactive microsphere technique, regional cerebral blood flow (rCBF) and total CBF were examined in rats at three time periods: baseline (CBF1) during 1.5 MAC inspired isoflurane-oxygen anesthesia, CBF2; during 1, 5, and CBF3; during isof-lureane and hemorrhage plus phenylephrine infused to restore mean arterial pressure (MAP) to baseline as mentioned in this paper.
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Abstract: Using the radioactive microsphere technique regional cerebral blood flow (rCBF) and total CBF (tCBF) were examined in rats at three time periods: baseline (CBF1) during 1.5 MAC inspired isoflurane-oxygen anesthesia, CBF2; during 1.5 MAC inspired isoflurane anesthesia combined with hypotension induced by hemorrhage and CBF3; during isoflurane and hemorrhage plus phenylephrine infused to restore mean arterial pressure (MAP) to baseline. For CBF1 MAP was 89 +/- 3 mmHg (mean +/- SEM, n = 9) with PaCO2 44 +/- 1 mmHg. For CBF2 following graded hemorrhage MAP was 48 +/- 2 mmHg and PaCO2 43 +/- 1 mmHg. For CBF3 MAP was 93 +/- 2 and PaCO2 45 +/- 1 mmHg, following infusion of phenylephrine (PE) at 13.9 +/- 4.0 micrograms.kg-1.min-1. Total CBF1 was 1.84 +/- 0.18 ml.g-1.min-1, tCBF2 1.32 +/- 0.09 ml.g-1.min-1 (P less than 0.05 vs. tCBF1) and tCBF3 2.60 +/- 0.18 (P less than 0.05 vs. tCBF1 and 2). For tCBF3 hemoglobin concentration had decreased 23% from 14.2 +/- 0.2 g.100 ml-1 to 11.0 +/- 0.5 g.100 ml-1 (P less than 0.05). Regional CBF decreased significantly in seven of 12 regions examined from CBF1 to CBF2 and was significantly higher in all regions for CBF3. For CBF1-3 infratentorial blood flows (cerebellar and brain stem) were significantly higher than flows to the supratentorial structures (cerebral cortical and basal ganglia). During isoflurane anesthesia, phenylephrine infused to support MAP following hemorrhagic hypotension effectively maintains rCBF and tCBF. There is no indication that phenylephrine infused to increase MAP following hemorrhage results in cerebral vasoconstriction in rats anesthetized with isoflurane.
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Citations
Attenuation of the haemodynamic response to placement of the Mayfield skull pin head holder: alfentanil versus scalp block
TL;DR: In this article, the authors compared two methods, namely alfentanil bolus (Group A) and nerve block of the scalp (Group B), to attenuate the haemodynamic response of the Mayfield clamp.
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Cerebral haemodynamic changes during propofol–remifentanil or sevoflurane anaesthesia: transcranial Doppler study under bispectral index monitoring
Alfredo Conti,Domenico Gerardo Iacopino,Vincenzo Fodale,S. Micalizzi,Olivia Penna,Letterio B. Santamaria +5 more
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