Neuroanaesthesia

Dagal, Armagan; Lam, Arthur M.

doi:10.1017/cbo9780511977558.012

Cited by 2 publications

(1 citation statement)

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“…Vasopressors are frequently used to increase blood pressure in order to ensure sufficient cerebral perfusion and oxygenation (CPO) during hypotensive periods induced by e.g. anaesthesia or septic shock [ 1 – 4 ]. Two of the most commonly used vasopressors are norepinephrine and phenylephrine [ 5 ].…”

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confidence: 99%

The influence of norepinephrine and phenylephrine on cerebral perfusion and oxygenation during propofol–remifentanil and propofol–remifentanil–dexmedetomidine anaesthesia in piglets

et al. 2018

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BackgroundVasopressors are frequently used to increase blood pressure in order to ensure sufficient cerebral perfusion and oxygenation (CPO) during hypotensive periods in anaesthetized patients. Efficacy depends both on the vasopressor and anaesthetic protocol used. Propofol–remifentanil total intravenous anaesthesia (TIVA) is common in human anaesthesia, and dexmedetomidine is increasingly used as adjuvant to facilitate better haemodynamic stability and analgesia. Little is known of its interaction with vasopressors and subsequent effects on CPO. This study investigates the CPO response to infusions of norepinephrine and phenylephrine in piglets during propofol–remifentanil and propofol–remifentanil–dexmedetomidine anaesthesia. Sixteen healthy female piglets (25–34 kg) were randomly allocated into a two-arm parallel group design with either normal blood pressure (NBP) or induced low blood pressure (LBP). Anaesthesia was induced with propofol without premedication and maintained with propofol–remifentanil TIVA, and finally supplemented with continuous infusion of dexmedetomidine. Norepinephrine and phenylephrine were infused in consecutive intervention periods before and after addition of dexmedetomidine. Cerebral perfusion measured by laser speckle contrast imaging was related to cerebral oxygenation as measured by an intracerebral Licox probe (partial pressure of oxygen) and transcranial near infrared spectroscopy technology (NIRS) (cerebral oxygen saturation).ResultsDuring propofol–remifentanil anaesthesia, increases in blood pressure by norepinephrine and phenylephrine did not change cerebral perfusion significantly, but cerebral partial pressure of oxygen (Licox) increased following vasopressors in both groups and increases following norepinephrine were significant (NBP: P = 0.04, LBP: P = 0.02). In contrast, cerebral oxygen saturation (NIRS) fell significantly in NBP following phenylephrine (P = 0.003), and following both norepinephrine (P = 0.02) and phenylephrine (P = 0.002) in LBP. Blood pressure increase by both norepinephrine and phenylephrine during propofol–remifentanil–dexmedetomidine anaesthesia was not followed by significant changes in cerebral perfusion. Licox measures increased significantly following both vasopressors in both groups, whereas the decreases in NIRS measures were only significant in the NBP group.ConclusionsCerebral partial pressure of oxygen measured by Licox increased significantly in concert with the vasopressor induced increases in blood pressure in healthy piglets with both normal and low blood pressure. Cerebral oxygenation assessed by intracerebral Licox and transcranial NIRS showed opposing results to vasopressor infusions.Electronic supplementary materialThe online version of this article (10.1186/s13028-018-0362-z) contains supplementary material, which is available to authorized users.

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Section: Main Textmentioning

confidence: 99%

The influence of norepinephrine and phenylephrine on cerebral perfusion and oxygenation during propofol–remifentanil and propofol–remifentanil–dexmedetomidine anaesthesia in piglets

et al. 2018

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The effect of dexmedetomidine on cerebral perfusion and oxygenation in healthy piglets with normal and lowered blood pressure anaesthetized with propofol-remifentanil total intravenous anaesthesia

et al. 2017

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BackgroundDuring anaesthesia and surgery, in particular neurosurgery, preservation of cerebral perfusion and oxygenation (CPO) is essential for normal postoperative brain function. The isolated effects on CPO of either individual anaesthetic drugs or entire anaesthetic protocols are of importance in both clinical and research settings. Total intravenous anaesthesia (TIVA) with propofol and remifentanil is widely used in human neuroanaesthesia. In addition, dexmedetomidine is receiving increasing attention as an anaesthetic adjuvant in neurosurgical, intensive care, and paediatric patients. Despite the extensive use of pigs as animal models in neuroscience and the increasing use of both propofol-remifentanil and dexmedetomidine, very little is known about their combined effect on CPO in pigs with uninjured brains. This study investigates the effect of dexmedetomidine on CPO in piglets with normal and lowered blood pressure during background anaesthesia with propofol-remifentanil TIVA. Sixteen healthy female Danish pigs (crossbreeds of Danish Landrace, Yorkshire and Duroc, 25–34 kg) were used. Three animals were subsequently excluded. The animals were randomly allocated into one of two groups with either normal blood pressure (NBP, n = 6) or with induced low blood pressure (LBP, n = 7). Both groups were subjected to the same experimental protocol. Intravenous propofol induction was performed without premedication. Anaesthesia was maintained with propofol-remifentanil TIVA, and later supplemented with continuous infusion of dexmedetomidine. Assessments of cerebral perfusion obtained by laser speckle contrast imaging (LSCI) were related to cerebral oxygenation measures (PbrO2) obtained by an intracerebral Clark-type Licox probe.ResultsAddition of dexmedetomidine resulted in a 32% reduction in median PbrO2 values for the LBP group (P = 0.03), but no significant changes in PbrO2 were observed for the NBP group. No significant changes in LSCI readings were observed in either group between any time points, despite a 28% decrease in the LBP group following dexmedetomidine administration. Caval block resulted in a significant (P = 0.02) reduction in median MAP from 68 mmHg (range 63–85) at PCB to 58 mmHg (range 53–63) in the LBP group, but no significant differences in either PbrO2 or LSCI were observed due to this intervention (P = 0.6 and P = 0.3 respectively).ConclusionsAddition of dexmedetomidine to propofol-remifentanil TIVA resulted in a significant decrease in cerebral oxygenation (PbrO2) measurements in piglets with lowered blood pressure. Cerebral perfusion (LSCI) did not decrease significantly in this group. In piglets with normal blood pressure, no significant changes in cerebral perfusion or oxygenation were seen in response to addition of dexmedetomidine to the background anaesthesia.Electronic supplementary materialThe online version of this article (doi:10.1186/s13028-017-0293-0) contains supplementary material, which is available to authorized users.

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Neuroanaesthesia

Cited by 2 publications

References 252 publications

The influence of norepinephrine and phenylephrine on cerebral perfusion and oxygenation during propofol–remifentanil and propofol–remifentanil–dexmedetomidine anaesthesia in piglets

The influence of norepinephrine and phenylephrine on cerebral perfusion and oxygenation during propofol–remifentanil and propofol–remifentanil–dexmedetomidine anaesthesia in piglets

The effect of dexmedetomidine on cerebral perfusion and oxygenation in healthy piglets with normal and lowered blood pressure anaesthetized with propofol-remifentanil total intravenous anaesthesia

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