Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2013
Randomized Controlled TrialHypobaric spinal anesthesia with ropivacaine plus sufentanil for traumatic femoral neck surgery in the elderly: a dose-response study.
In this randomized, prospective trial, we sought to determine the effective dose of hypobaric ropivacaine with sufentanil providing 95% success (ED95) in spinal anesthesia for traumatic femoral neck surgery in the elderly. ⋯ The effective dose of hypobaric ropivacaine combined with sufentanil 5 µg providing 95% success in spinal anesthesia for traumatic femoral neck surgery in the elderly is ED95 = 9 mg (95% confidence interval, 8-14). Using doses exceeding the ED95 may increase the incidence of hypotension. If doses less than the ED95 are chosen, the use of additional analgesia may be necessary.
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Anesthesia and analgesia · Jul 2013
Mechanism of autoinduction of methadone N-demethylation in human hepatocytes.
There is considerable interindividual and intraindividual variability in methadone metabolism and clearance. Methadone dosing is particularly challenging during initiation of therapy, because of time-dependent increases in hepatic clearance (autoinduction). Although methadone N-demethylation is catalyzed in vitro by cytochrome P4502B6 (CYP2B6) and CYP3A4, and clearance in vivo depends on CYP2B6, mechanism(s) of autoinduction are incompletely understood. In this investigation, we determined mechanism(s) of methadone autoinduction using human hepatocytes. ⋯ Methadone caused concentration-dependent autoinduction of methadone N-demethylation in human hepatocytes, related to induction of CYP2B6 and CYP3A4 mRNA expression, protein expression, and catalytic activity. Induction was related to pregnane X receptor but not constitutive androstane receptor activation. These in vitro findings provide mechanistic insights into clinical autoinduction of methadone metabolism and clearance.
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Anesthesia and analgesia · Jul 2013
ReviewReview article: is ultrasound guidance advantageous for interventional pain management? A systematic review of chronic pain outcomes.
Modern ultrasound (US) is an attractive alternative to anatomical landmark-, nerve stimulation-, and fluoroscopic-guided techniques for interventional procedures performed to treat chronic pain syndromes. ⋯ There are presently insufficient data to support improved efficacy with procedures performed with US guidance for relieving both short- and long-term chronic pain.
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Anesthesia and analgesia · Jul 2013
The effect of full expiration on the position and size of the subclavian vein in spontaneously breathing adults.
If full expiration during subclavian venous cannulation increases the distance between the subclavian vein (SCV) and the pleura or increases the diameter of the vein, it might decrease the incidence of pneumothorax and/or increase the success rate of venous cannulation. In this study, we evaluated the effect of full expiration on the distance from the SCV to the pleura and on the crosssectional area (CSA) of the SCV in spontaneously breathing adults. ⋯ The distance from the SCV to the pleura did not change after full expiration. However, this simple technique can still be considered during placement of subclavian catheters in spontaneously breathing patients, because it significantly enlarges the CSA of the SCV.