Anesthesia and analgesia
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Anesthesia and analgesia · Jul 2006
General anesthesia and chronic amphetamine use: should the drug be stopped preoperatively?
Prescription amphetamines are being used more often for several medical conditions. Anesthesia concerns focus on the cardiovascular stability of patients who may be catecholamine-depleted and thus have a blunted response to intraoperative hypotension. Previously we reported one case of a patient receiving chronic amphetamine therapy who had a stable intraoperative course. ⋯ All required general anesthesia for their surgical procedures and 6 of the 8 patients were tracheally intubated. Anesthesia operating room times ranged from 30 min to 4.25 h. The authors conclude that amphetamine use need not be stopped before surgery and anesthesia.
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Anesthesia and analgesia · Jul 2006
Neuraxial anesthesia and analgesia in patients with preexisting central nervous system disorders.
Historically, the use of regional anesthetic techniques in patients with preexisting central nervous system (CNS) disorders has been considered relatively contraindicated. The fear of worsening neurologic outcome secondary to mechanical trauma, local anesthetic toxicity, or neural ischemia is commonly reported. We examined the frequency of new or progressive neurologic complications in patients with preexisting CNS disorders who subsequently underwent neuraxial blockade. ⋯ A satisfactory block was reported in 136 (98%) patients. No new or worsening postoperative neurologic deficits occurred when compared to preoperative findings (0.0%; 95% confidence interval, 0.0%-0.3%). We conclude that the risks commonly associated with neuraxial anesthesia and analgesia in patients with preexisting CNS disorders may not be as frequent as once thought and that neuraxial blockade should not be considered an absolute contraindication within this patient population.
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Anesthesia and analgesia · Jul 2006
Peripheral flow index is a reliable and early indicator of regional block success.
We investigated the usefulness of peripheral flow index (PFI) measurement using a standard pulse oximetry digit probe for early prediction of successful regional blocks. Sixty-six patients scheduled for limb surgery underwent either axillary or sciatic block using a nerve stimulator technique with mepivacaine 1.5%. PFI, which is the ratio of the pulsatile versus the nonpulsatile component of the pulse oximetry signal, was recorded from 10 min before block insertion until 30 min afterwards. ⋯ At 15 min after block placement, cold and pinprick sensations had the same calculated values for sensitivity and specificity at 71% and 100%, respectively, for axillary blocks. For sciatic blocks, cold sensation had a sensitivity of 77% and a specificity of 100%, whereas pinprick had a sensitivity of just 20% with a specificity of 100%. We conclude that PFI provides a simple, early, and objective assessment of the success and failure of nerve blocks.
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Anesthesia and analgesia · Jul 2006
A surprising twist: an unusual failure of a keyed filling device specific for a volatile inhaled anesthetic.
We describe two cases in which keyed filling devices for sevoflurane were inadvertently screwed onto isoflurane bottles. The mishaps were possible because the collars on sevoflurane and isoflurane bottles are mirror images of each other. ⋯ The keyed filling adapters for sevoflurane and isoflurane could each be manipulated to fit the other's bottle. A manufacturer (Southmedic, Inc., Barrie, Canada) has modified their keyed filling adapters to prevent this unusual circumstance from recurring.
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The risk of postoperative nausea and vomiting (PONV) is reduced in cigarette smokers by unknown mechanisms. If protection is related to an acute effect of smoke constituents, smokers with the most recent exposure to cigarette smoke would be most protected. We tested the hypothesis that in cigarette smokers, postoperative nausea is correlated with recent exposure to cigarette smoke as quantified by exhaled carbon monoxide (CO) concentrations. ⋯ Significant correlations were found between nausea assessed over the first 24 h postoperatively and a history of PONV or motion sickness, the use of intraoperative antiemetic prophylaxis, duration of anesthesia, and use of opioids in the postanesthesia care unit. However, there was no correlation between preoperative CO and nausea over the first 24 h. These preliminary data suggest that the effect of smoking in reduced PONV is not directly related to preoperative exhaled CO levels.