Anesthesiology
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Randomized Controlled Trial Clinical Trial
Clinical trial of a new lightwand device (Trachlight) to intubate the trachea.
Transillumination of the soft tissue of the neck using a lighted stylet (lightwand) is an effective and safe intubating technique. A newly designed lightwand (Trachlight) incorporates modifications to improve the brightness of the light source as well as flexibility. The goal of this study was to determine the effectiveness and safety of this device in intubating the trachea of elective surgical patients. ⋯ In contrast to laryngoscopy, the ease of intubation using the Trachlight does not appear to be influenced by anatomic variations of the upper airway. Intubation occasionally failed with the Trachlight but in all cases was resolved with direct laryngoscopy. The failures of direct laryngoscopy were resolved with Trachlight. Thus the combined technique was 100% successful in intubating the tracheas of all patients.
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Compared with conventional routes of delivering potent analgesics to postoperative patients, transdermal administration of fentanyl offers the advantages of simplicity and noninvasive delivery. The only available form of transdermal fentanyl, the Duragesic system, has been implicated in preventable patient deaths when used for postoperative analgesia and is contraindicated in the management of postoperative pain. We examined the biopharmaceutics of a new transdermal fentanyl device developed by Cygnus and intended for use as a postoperative analgesic to see whether the new formulation offers pharmacokinetic advantages that might permit safe use in postoperative patients. ⋯ The Cygnus transdermal fentanyl device shows great variability in the rate of fentanyl absorption, resulting in highly variable plasma fentanyl concentrations. Some persons may rapidly absorb fentanyl from the device in the first few hours after application, leading to fentanyl toxicity. The variability in effect of the Cygnus transdermal fentanyl device is appreciably greater than that reported for the currently available Duragesic transdermal fentanyl device, which is contraindicated for postoperative analgesia.
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In studies of methoxyflurane-induced nephrotoxicity, renal-concentrating impairment has been observed only when serum inorganic fluoride concentrations exceed 50 microM. Prolonged sevoflurane anesthesia can result in serum inorganic fluoride concentrations in excess of 50 microM. The authors compared renal function after prolonged sevoflurane anesthesia with that after isoflurane anesthesia. In addition, they measured urinary excretion of N-acetyl-beta-glucosaminidase (NAG), a sensitive index of renal tubular damage, during the 3-day period after anesthesia. ⋯ The authors concluded that sevoflurane anesthesia results in increased serum fluoride concentration, a tendency toward decreased maximal ability to concentrate urine, and increased excretion of NAG. However, the increase in urinary NAG excretion was not indicative of clinically significant renal damage in these patients with no preexisting renal disease.
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Fentanyl is used in anesthetic protocols for swine, but there are no reports on its potency in this species. This study measured the extent to which fentanyl reduces the minimum alveolar concentration of isoflurane (MACISO) in swine. ⋯ These fentanyl dosages are larger than those commonly used in humans and other species. Anesthetic protocols using fentanyl for swine should be designed with the knowledge that a fentanyl infusion of 200 micrograms.kg-1.h-1 contributes approximately a 50% MACISO equivalent.
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During peripheral nerve block, local anesthetic (LA) penetrates within and along the nerve to produce the observed functional deficits. Although much is known about the kinetics and steady-state relation for LA inhibition of impulse activity in vitro in isolated nerve, little is known about the relation between functional loss and intraneural LA content in vivo. This study was undertaken to investigate the relation of functional change to intraneural LA. ⋯ During peripheral nerve block only a small amount of injected LA penetrates into the nerve. The intraneural content of LA correlates with the depth of functional block.