Journal of neurosurgical anesthesiology
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J Neurosurg Anesthesiol · Jul 2013
Clinical validity of cerebral oxygen saturation measured by time-resolved spectroscopy during carotid endarterectomy.
Near-infrared spectroscopy has been used clinically to continuously and noninvasively monitor cerebral oxygen saturation (ScO2). However, there is no gold standard for measuring absolute values of ScO2. Although time-resolved spectroscopy (TRS) is one of the most reliable algorithms that reliably calculate absolute values of ScO2, there are very few clinical studies available. To evaluate the clinical relevance of ScO2 measurements using TRS, we compared ScO2 with jugular venous oxygen saturation (SjO2) during carotid endarterectomy. We also investigated factors associated with cerebral oxygen desaturation during clamping of the carotid artery. ⋯ ScO2 measured by TRS and SjO2 showed narrow limits of agreement. Reduced ScO2 was significantly associated with impaired cerebral hemodynamics.
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J Neurosurg Anesthesiol · Jul 2013
Effects of positive end expiratory pressure (PEEP) on intracranial and cerebral perfusion pressure in pediatric neurosurgical patients.
Positive end expiratory pressure (PEEP) improves oxygenation by optimizing alveolar recruitment and reducing intrapulmonary shunt. Unfortunately, PEEP can interfere with intracranial pressure (ICP) by increasing intrathoracic pressure. We hypothesized that the use of different PEEP levels could have an effect on intracranial and cerebral perfusion pressure (CPP), gas exchange, respiratory system mechanics, and hemodynamics in pediatric patients undergoing major neurosurgical procedures. ⋯ We describe cerebral hemodynamic responses to PEEP application in pediatrics. PEEP values up to 8 cm H2O seem to be safe in pediatric patients with intracranial neoplasm, and, in our opinion, PEEP should be applied immediately after surgery to restore lung recruitment.
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J Neurosurg Anesthesiol · Jul 2013
Biphasic change of progenitor proliferation in dentate gyrus after single dose of isoflurane in young adult rats.
Isoflurane exposure causes improvement in long-term neurocognitive function in young adult rats; this is associated with an increase in dentate gyrus (DG) progenitor proliferation 4 days after anesthesia. However, the number of new neurons that were born from cells that incorporated bromodeoxyuridine (BrdU) 4 days after anesthesia is not affected by anesthesia. We tested the hypothesis that progenitor proliferation continues to increase past 4 days, which would imply the possibility that the number of new neurons after anesthesia could be increased if BrdU labeling occurred at a later time point. ⋯ Anesthesia-induced progenitor proliferation in the DG was not sustained 9 days after anesthesia. We interpret these results to signify that an anesthetic effect on neurogenesis likely does not play a critical role in the previously observed isoflurane-induced long-term improvement in neurocognitive function in 60-day old rats and that the transient increase in progenitor proliferation serves to replenish the pool of neural stem cells. The mechanism of anesthesia-induced improvement in cognition of young adult rats remains elusive.
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J Neurosurg Anesthesiol · Jul 2013
The effect of pumpless extracorporeal CO2 removal on regional perfusion of the brain in experimental acute lung injury.
Lung-protective mechanical ventilation with low tidal volumes (V(T)) is often associated with hypercapnia (HC), which may be unacceptable in patients with brain injury. CO2 removal using a percutaneous extracorporeal lung assist (pECLA) enables normocapnia despite low V(T), but its effects on regional cerebral blood flow (rCBF) remain ambiguous. We hypothesized that reversal of HC by pECLA impairs rCBF in a porcine lung injury model. ⋯ In this animal model, mechanical ventilation with low V(T) was associated with HC and increased rCBF. CO2 removal by pECLA restored normocapnia, reduced rCBF to levels of normocapnia, but required a higher systemic blood flow for the perfusion of the pECLA device. If these results could be transferred to patients, extracorporeal CO2 removal might be an option for treatment of combined lung and brain injury in condition of a sufficient cardiac flow reserve.