Anesthesia and analgesia
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Anesthesia and analgesia · Jun 1997
Cerebral hemoglobin and optical pathlength influence near-infrared spectroscopy measurement of cerebral oxygen saturation.
Near-infrared spectroscopy (NIRS) is a noninvasive optical technique to monitor cerebral oxygen saturation at the bedside. Despite its applicability, NIRS has had limited clinical use because of concerns about accuracy, noted by intersubject variability in slope and intercept of the line between NIRS- and weighted-average arterial-cerebrovenous saturation (SMO2). This study evaluated transcranial optical pathlength and cerebral hemoglobin concentration as sources for this intersubject variability. ⋯ By adjusting the NIRS algorithm with the cerebral hemoglobin measurements, slope and intercept remained unchanged by hemodilution. These data indicate that intersubject variability in NIRS originates, in part, from biologic variations in transcranial optical pathlength and cerebral hemoglobin concentration. Instruments to account for these factors may improve NIRS cerebral oxygen saturation measurements.
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Anesthesia and analgesia · May 1997
Randomized Controlled Trial Multicenter Study Clinical TrialDose-ranging study in younger adult and elderly patients of ORG 9487, a new, rapid-onset, short-duration muscle relaxant.
The purpose of this multicenter, randomized, assessorblind placebo-controlled study was to determine which of five doses of the new, rapid-onset neuromuscular relaxant, ORG 9487, provided both good to excellent tracheal intubating conditions 60 s after administration and a clinical duration of action < 20 min in 120 younger (aged 18-64 yr) and 61 elderly (aged 65-85 yr) adult patients. Anesthesia was induced with fentanyl (2-5 micrograms/kg) and thiopental (3-6 mg/kg) and maintained with N2O/O2 and a propofol infusion (50-300 micrograms.kg-1.min-1). Neuromuscular train-of-four (TOF) monitoring by electromyography (Datex Relaxograph) commenced immediately after anesthetic induction and was followed, within 30 s, by one of five doses of ORG 9487 (0.5, 1.0, 1.5, 2.0, 2.5 mg/kg) or a placebo. ⋯ Good to excellent intubating conditions at 60 s were present in most younger adult (52 of 60) and elderly (26 of 31) patients administered doses > or = 1.5 mg/kg. Mean clinical durations < 20 min were observed in adult patients at doses up to 2.0 mg/kg and in geriatric patients up to 1.5 mg/kg. Thus, doses of 1.5-2.0 mg/kg ORG 9487 enabled both rapid tracheal intubation and a short clinical duration of action in adult and elderly patients.
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Anesthesia and analgesia · May 1997
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized multicenter study of remifentanil compared with alfentanil, isoflurane, or propofol in anesthetized pediatric patients undergoing elective strabismus surgery.
Remifentanil hydrochloride is a new, ultrashort-acting opioid metabolized by nonspecific plasma and tissue esterases. We conducted this multicenter study to examine the hemodynamic response and recovery profile of premedicated children undergoing strabismus repair who were randomly assigned to receive one of four treatment drugs (remifentanil, alfentanil, isoflurane, or propofol) along with nitrous oxide and oxygen for maintenance of anesthesia. Induction of anesthesia was by nitrous oxide, oxygen, and halothane or nitrous oxide, oxygen, and propofol. ⋯ Its hemodynamic and recovery profile appear similar to other comparable drugs. Based on previous pharmacokinetic studies, the 1.0 microgram.kg-1.min-1 infusion may be twice the 50% effective dose observed in adults. In this study, the relative "overdose" of remifentanil was well tolerated and did not prolong recovery.
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Anesthesia and analgesia · May 1997
Randomized Controlled Trial Comparative Study Clinical TrialThiopental-rocuronium versus ketamine-rocuronium for rapid-sequence intubation in parturients undergoing cesarean section.
We investigated the neuromuscular effects and conditions of tracheal intubation after administration of rocuronium in 40 parturients undergoing elective cesarean section. After preoxygenation, anesthesia was induced in 20 patients by thiopental 4 mg/kg and, in the other 20 patients, by ketamine 1.5 mg/kg. Rocuronium 0.6 mg/kg was then administered, and neuromuscular transmission was assessed using electromyographic response to train-of-four stimulation of the ulnar nerve at the wrist every 10 s. ⋯ Neither the time to 50% NMB nor the onset time were significantly different between the two groups. Tracheal intubation at 50% NMB was easily performed in all patients in the ketamine-rocuronium group but was difficult in 75% of the thiopental-rocuronium group. We concluded that ketamine 1.5 mg/kg followed by rocuronium 0.6 mg/kg may be suitable for rapid-sequence induction of anesthesia in parturients undergoing cesarean section.