Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyNitrous oxide and anesthetic requirement for loss of response to command during propofol anesthesia.
The blood concentration associated with loss of response (LOR) to command in 50% of subjects (CP50(LOR)) is an important measure of anesthetic potency. We therefore determined the CP50(LOR) in 40 healthy surgical patients, aged 18-60 yr old, receiving propofol alone or propofol with 67% nitrous oxide (N2O). Patients were randomized to receive 100% oxygen or 67% N2O in oxygen via facemask. ⋯ At testing for response to command, both the measured and target propofol concentrations were significantly larger and BIS values significantly smaller in the propofol-alone group compared with the propofol-N2O group. The CP50(LOR) of propofol in the propofol-alone group was 4.58 mug/mL (95% confidence interval [CI], 1.14-15.36) and 2.67 microg/mL (95% CI, 2.28-3.17) in the propofol-N2O group. The BIS value when 50% of patients responded to command was 60 (95% CI, 55-65) in the propofol-alone group and 75 (95% CI, 73-83) in the propofol-N2O group.
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Anesthesia and analgesia · Apr 2006
Randomized Controlled Trial Comparative StudyPrevention of emergence agitation after sevoflurane anesthesia for pediatric cerebral magnetic resonance imaging by small doses of ketamine or nalbuphine administered just before discontinuing anesthesia.
Magnetic resonance imaging (MRI) requires long-lasting immobilization that frequently can only be provided by general anesthesia in pediatric patients. Sevoflurane provides adequate anesthesia but many patients experience emergence agitation. Small doses of ketamine and nalbuphine provide moderate sedation but their benefits have subsided at the time of emergence. ⋯ All patients met discharge criteria at 30 min but significantly more children were awake and quiet in the K-group and still more in the N-group. In conclusion, small doses of ketamine or nalbuphine administered at the end of an MRI procedure under sevoflurane anesthesia reduce emergence agitation without delaying discharge. Nalbuphine provided better results than ketamine.
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Anesthesia and analgesia · Apr 2006
Comparative StudyLocal anesthetic-induced protection against lipopolysaccharide-induced injury in endothelial cells: the role of mitochondrial adenosine triphosphate-sensitive potassium channels.
Lidocaine attenuates cell injury induced by ischemic-reperfusion and inflammation, although the protective mechanisms are not understood. We hypothesized that lidocaine and other amide local anesthetics protect against endothelial cell injury through activation of the mitochondrial adenosine triphosphate-sensitive potassium (mitoK(ATP)) channels. We determined the effects of amide local anesthetics (lidocaine, ropivacaine, and bupivacaine), ester local anesthetics (tetracaine and procaine), one amide analog (YWI), and two non-amide local anesthetic analogs (JDA and ICM) on viability of human microvascular endothelial cells after exposure to lipopolysaccharide (LPS) in the absence or presence of the mitoK(ATP) channel antagonist 5-hydroxydecaonate. ⋯ In conclusion, amide local anesthetics and the amide analog (YWI) attenuate LPS-induced cell injury, in part, through activation of mitoK(ATP) channels. In contrast, tetracaine and procaine had no protective effects and inhibited activation of mitoK(ATP) channels. The non-amide local anesthetic analogs induced protection but through mechanisms independent of mitoK(ATP) channels.
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Anesthesia and analgesia · Apr 2006
Comparative StudyAnesthetic requirements and stress hormone responses in spinal cord-injured patients undergoing surgery below the level of injury.
Neuraxial anesthesia decreases the minimum alveolar concentration. We determined the effects of spinal cord injury (SCI) on sevoflurane requirements and stress hormone response. Twenty-two chronic SCI patients undergoing surgery below the level of the injury were enrolled in the study, and 15 patients without cord injury served as control patients. ⋯ In the control group, plasma norepinephrine and cortisol concentrations were significantly increased during and 1 h after surgery compared with awake baseline values. In the SCI group, the sympathoadrenal and cortisol responses were virtually abolished. We conclude that SCI reduces the anesthetic requirement by 20%-39% during surgery below the level of injury, in association with blunted sympathoadrenal and cortisol responses.