Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1997
Randomized Controlled Trial Clinical TrialEffect of dexmedetomidine on lumbar cerebrospinal fluid pressure in humans.
Dexmedetomidine's potential for analgesia without respiratory depression and its opioid- and anesthetic-sparing properties make it an attractive choice as an anesthetic adjunct for patients undergoing neurosurgery. However, the effects of dexmedetomidine on intracranial pressure are not known. We therefore studied the effect of dexmedetomidine on lumbar cerebrospinal fluid (CSF) pressure in patients after transphenoidal pituitary tumor surgery. Sixteen transphenoidal pituitary tumor surgery patients were randomized to receive placebo (n = 9) or dexmedetomidine (n = 7) for 60 min in the postanesthesia care unit. The study drug was administered by a continuous computer-controlled infusion to achieve an estimated plasma dexmedetomidine concentration of 600 pg/mL, the highest plasma concentration that has been used for clinical purposes. Patient-controlled analgesia was used to administer morphine for postoperative discomfort. Lumbar CSF pressure (via lumbar intrathecal catheter), intraarterial blood pressure, and heart rate were monitored continuously. There was no change in lumbar CSF pressure in either group. The highest values obtained were 19 mm Hg in the dexmedetomidine group and 20 mm Hg in the placebo group. During infusion, mean arterial pressure decreased from 103 +/- 10 mm Hg to 86 +/- 6 mm Hg (P < 0.05), heart rate decreased from 77 +/- 12 bpm to 64 +/- 7 bpm (P < 0.05), and cerebral perfusion pressure decreased from 95 +/- 8 mm Hg to 78 +/- 6 mm Hg (P < 0.05) in the dexmedetomidine group, but not in the placebo group. We conclude that dexmedetomidine does not have an effect on lumbar CSF pressure in patients with normal intracranial pressure who have undergone transphenoidal pituitary hypophysectomy. ⋯ The effects of dexmedetomidine (an alpha2-agonist) or placebo on lumbar cerebrospinal fluid pressure, measured via an intrathecal catheter, were studied postoperatively in 16 patients. Dexmedetomidine had no effect on lumbar cerebrospinal fluid pressure. We will continue to investigate the potential utility of dexmedetomidine for neurosurgical anesthesia.
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Anesthesia and analgesia · Aug 1997
Randomized Controlled Trial Comparative Study Clinical TrialImmediate 8% sevoflurane induction in children: a comparison with incremental sevoflurane and incremental halothane.
We compared the efficacy and tolerance of pediatric inductions with immediate 8% sevoflurane in 70% nitrous oxide with either incremental sevoflurane or incremental halothane in 70% nitrous oxide. Forty-six unpremedicated children had anesthesia induced by immediate 8% sevoflurane (high sevoflurane [HS]; circuit primed with 70% N2O and 8% sevoflurane before application of the face mask), gradual sevoflurane (GS; primed with 70% N2O with increments of sevoflurane), and gradual halothane (HAL; 70% N2O with incremental halothane). Blind video recordings were made, and each child's distress was rated prior to mask application, during mask application, and every 10 s thereafter using a behavioral rating scale. ⋯ Times to eye closure were also significantly different (P < 0.001): HS 37 +/- 10 s (range 15-56); GS 70 +/- 18 s (range 35-114); HAL 81 +/- 34 s (range 55-140). Distress scale scores showed more rapid decrement with HS than with GS or HAL. We conclude that 1) immediate 8% sevoflurane/N2O results in a significantly faster induction than GS or HAL;2) in children, HS in N2O will not result in a single-breath induction under the conditions of this study; 3) in this small group, HS was extremely well tolerated in ASA class I and II patients.
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Anesthesia and analgesia · Aug 1997
Randomized Controlled Trial Clinical TrialMidazolam premedication increases sedation but does not prolong discharge times after brief outpatient general anesthesia for laparoscopic tubal sterilization.
Preoperatively administered midazolam may contribute to postoperative sedation and delayed recovery from brief outpatient general anesthesia, particularly in patients who receive significant postoperative opioid analgesics. We evaluated the effects of midazolam premedication (0.04 mg/kg) on postoperative sedation and recovery times after laparoscopic tubal sterilization (Falope rings) in 30 healthy women in a randomized, double-blind, placebo-controlled study. Patients received midazolam or saline-placebo intravenously 10 min before anesthesia. ⋯ Midazolam was associated with impairment of performance on the TDT and DSST after premedication administration and 15 (TDT and DSST) and 30 (DSST) min after postanesthesia care unit (PACU) arrival. There were no differences in PACU time and time to discharge-readiness. In conclusion, midazolam premedication augments postoperative sedation in this population but does not prolong recovery times.
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Anesthesia and analgesia · Aug 1997
Randomized Controlled Trial Comparative Study Clinical TrialThe arterial blood propofol concentration preventing movement in 50% of healthy women after skin incision.
To target appropriate drug concentrations and to facilitate comparisons between drugs, the potency of propofol must be firmly established. We therefore determined the arterial blood propofol concentration preventing movement in 50% of patients after skin incision and the ability of arterial blood pressure and heart rate to predict movement after incision. Fifteen healthy women scheduled for breast surgery were randomly assigned to computer-targeted propofol blood concentrations. ⋯ The MABP50 and MABP95 values were 63 +/- 4 mm Hg and 43 mm Hg, respectively. Heart rate did not differ significantly in patients who moved and who did not move. Propofol blood concentrations required to prevent movement in most patients resulted in significant arterial hypotension.
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Anesthesia and analgesia · Aug 1997
Randomized Controlled Trial Clinical TrialThe effect of ephedrine on the onset time of rocuronium.