Anesthesia and analgesia
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Anesthesia and analgesia · Jan 2005
Anesthetic preconditioning: the role of free radicals in sevoflurane-induced attenuation of mitochondrial electron transport in Guinea pig isolated hearts.
Cardioprotection by anesthetic preconditioning (APC) can be abolished by nitric oxide (NO*) synthase inhibitors or by reactive oxygen species (ROS) scavengers. We previously reported attenuated mitochondrial electron transport (ET) and increased ROS generation during preconditioning sevoflurane exposure as part of the triggering mechanism of APC. We hypothesized that NO* and other ROS mediate anesthetic-induced ET attenuation. ⋯ Both this NADH increase and the cardioprotection by APC on reperfusion were prevented by superoxide dismutase, catalase, and glutathione and by N(G)-nitro-L-arginine-methyl-ester. Thus, ROS and NO*, or reaction products including peroxynitrite, mediate sevoflurane-induced ET attenuation. This may lead to a positive feedback mechanism with augmented ROS generation to trigger APC secondary to altered mitochondrial function.
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Anesthesia and analgesia · Jan 2005
Case ReportsIs ketamine a safe anesthetic for percutaneous liver biopsy in a liver transplant recipient immunosuppressed with cyclosporine?
A 6-yr-old male patient underwent live related left lateral segment liver transplant for cryptogenic cirrhosis with portal hypertension. One month after the liver transplant the patient had an isolated liver transaminases increase. He was posted for percutaneous liver biopsy for suspected graft rejection under general anesthesia. ⋯ Percutaneous liver biopsy was obtained once the convulsions subsided. Both ketamine and cyclosporine have been implicated as having proconvulsant properties and may have been responsible for the seizures in our patient. Our experience prompted us to suggest that ketamine in a patient immunosuppressed with cyclosporine may not be safe and that alternative anesthetics may need to be considered for such procedures.
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Anesthesia and analgesia · Jan 2005
The detection of cerebral hypoperfusion with bispectral index monitoring during general anesthesia.
We describe a patient in whom the bispectral index (BIS) decreased to 0 during surgery. A 42-yr-old man with chronic renal failure was scheduled to undergo construction of an arteriovenous shunt. He had a history of acute cerebral hemorrhage. ⋯ The decrease in BIS was suspected to be the result of decreased cerebral blood flow. The systolic blood pressure of 110 mm Hg (mean blood pressure, 80 mm Hg) was probably less than the lower limit of autoregulation. Although BIS has some limitations as a cerebral monitor, it was useful for detecting possible cerebral hypoperfusion in this case.
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Anesthesia and analgesia · Jan 2005
Mild hypothermia, but not propofol, is neuroprotective in organotypic hippocampal cultures.
The neuroprotective potency of anesthetics such as propofol compared to mild hypothermia remains undefined. Therefore, we determined whether propofol at two clinically relevant concentrations is as effective as mild hypothermia in preventing delayed neuron death in hippocampal slice cultures (HSC). Survival of neurons was assessed 2 and 3 days after 1 h oxygen and glucose deprivation (OGD) either at 37 degrees C (with or without 10 or 100 microM propofol) or at an average temperature of 35 degrees C during OGD (mild hypothermia). ⋯ In both CA1 neurons and cortical slices, blocking GABAA receptors with picrotoxin reduced the inhibition of GluRs substantially. We conclude that mild hypothermia, but not propofol, protects CA1 and CA3 neurons in hippocampal slice cultures subjected to oxygen and glucose deprivation. Propofol was not neuroprotective at concentrations that reduce glutamate and NMDA receptor responses in cortical and hippocampal neurons.
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Anesthesia and analgesia · Jan 2005
The effects of intravenous lidocaine administration on the minimum alveolar concentration of isoflurane in cats.
Lidocaine decreases the minimum alveolar concentration (MAC) of inhaled anesthetics and has been used clinically to reduce the requirements for other anesthetic drugs. In this study we examined the effects of lidocaine on isoflurane MAC in cats. Six cats were studied. ⋯ The MAC of isoflurane in this study was 2.21% +/- 0.17%, 2.14% +/- 0.14%, 1.88% +/- 0.18%, 1.66% +/- 0.16%, 1.47% +/- 0.13%, 1.33% +/- 0.23%, and 1.06% +/- 0.19% at lidocaine target plasma concentrations of 0, 1, 3, 5, 7, 9, and 11 microg/mL, respectively. Lidocaine, at target plasma concentrations of 1, 3, 5, 7, 9, and 11 microg/mL, linearly decreased isoflurane MAC by -6% to 6%, 7% to 28%, 19% to 35%, 28% to 45%, 29% to 53%, and 44% to 59%, respectively. We conclude that lidocaine decreases the MAC of isoflurane.