Anesthesia and analgesia
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Comparative Study Clinical TrialThe efficacy, side effects, and recovery characteristics of dexmedetomidine versus propofol when used for intraoperative sedation.
We evaluated the cardio-respiratory effects of equi-sedative doses of dexmedetomidine and propofol for intraoperative sedation. Secondary comparison end points were time to achieve and terminate sedation and postoperative analgesia and psychomotor performance. Forty patients scheduled for elective surgery provided informed consent and were randomized equally to receive either dexmedetomidine (1 microg/kg initial loading dose for 10 min; maintenance, 0.4-0.7 microg. kg(-1). h(-1)) or propofol (75 microg. kg(-1). min(-1) x 10 min; maintenance, 12.5-75 microg. kg(-1). min(-1)). Hemodynamic variables (heart rate and mean arterial blood pressure), sedation (visual analog scale and Observer Assessment of Alertness/Sedation), bispectral index score of sedation, ventilation (respiratory rate, O2 sat, and ETCO2), psychomotor performance (digital symbol substitution test), and pain (visual analog scale) were determined during surgery and up to 95 min after surgery. Intraoperative sedation levels were targeted to achieve a bispectral index score of 70-80. Patient demographics, ASA class, surgical procedure, and baseline cardio-respiratory variables were similar between groups. Sedation was achieved more rapidly with propofol but was similar between groups 25 min after initiating infusions. The average infusion rate for dexmedetomidine was 0.7 microg. kg(-1). h(-1) and 38 microg. kg(-1). min(-1) for propofol. There were no differences between groups in psychomotor performance and respiratory rate during recovery. The previous use of dexmedetomidine resulted in more sedation, lower blood pressure, and improved analgesia (less morphine use) in recovery. ⋯ Dexmedetomidine may be useful for perioperative sedation. It has a slower onset and offset of sedation compared with propofol. Dexmedetomidine was associated with improved analgesia and less morphine use in the postoperative period.
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Comparative Study Clinical TrialHemodynamic responses to tracheal intubation with laryngoscope versus lightwand intubating device (Trachlight) in adults with normal airway.
Lightwand devices are effective and safe as an aid to tracheal intubation. Theoretically, avoiding direct-vision laryngoscopy could allow for less stimulation by intubation than the conventional laryngoscopic procedure. We designed this prospective randomized study to assess the cardiovascular changes after either lightwand or direct laryngoscopic tracheal intubation in adult patients anesthetized with sevoflurane. Sixty healthy adult patients with normal airways were randomly assigned to one of three groups according to intubating procedure under sevoflurane/nitrous oxide anesthesia (fraction of inspired oxygen = 0.33) (n = 20 each). The lightwand group received tracheal intubation with Trachlight, the laryngoscope-intubation group received tracheal intubation with a direct-vision laryngoscope (Macintosh blade), and the laryngoscopy-alone group received the laryngoscope alone. Heart rate and systolic blood pressure were recorded continuously for 5 min after tracheal intubation or laryngoscopy with enough time to intubate. All procedures were successful on the first attempt. The maximum heart rate and systolic blood pressure values obtained after intubation with Trachlight (114 +/- 20 bpm and 143 +/- 30 mm Hg, respectively) did not differ from those with the Macintosh laryngoscope (114 +/- 20 bpm and 138 +/- 23 mm Hg), but they were significantly larger than those in the laryngoscopy-alone group (94 +/- 19 bpm and 112 +/- 21 mm Hg) (P < 0.05). Direct stimulation of the trachea appears to be a major cause of the hemodynamic changes associated with tracheal intubation. ⋯ The magnitude of hemodynamic changes associated with tracheal intubation with the Trachlight is almost the same as that which occurs with the direct laryngoscope. Hemodynamic changes are likely to occur because of direct tracheal irritation rather than direct stimulation of the larynx.
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Clinical TrialA double-blinded, randomized comparison of intrathecal and epidural morphine for elective cesarean delivery.
We randomized 150 parturients into a double-blinded trial to receive intrathecal (IT) 100 microg (IT 100 group) or 200 microg (IT 200 group) or epidural 3 mg (Epidural group) of morphine for elective cesarean delivery with a combined spinal/epidural technique. The patients additionally received ketoprofen 300 mg/d. Postoperative pain relief and side effects were registered every 3 h up to 24 h, and all patients were interviewed on the first postoperative day. Pain control was equally good, but the parturients in the IT 100 group requested rescue analgesics more often compared with the other groups (P < 0.05). Itching was a common complaint and was reported by 74% of the parturients in the Epidural group and 65% and 91% in the IT 100 and IT 200 groups, respectively (P < 0.01). Medication for itching was requested by 44%, 24%, and 45% of the patients, respectively (P < 0.05). There was no difference in postoperative nausea or vomiting. The pain relief was perceived as good by >90% of the patients in all groups. In conclusion, because of the decreased incidence of and lesser requirements of medication for itching, IT morphine 100 microg with ketoprofen is recommended in cesarean deliveries. Rescue analgesics nevertheless need to be prescribed. ⋯ Spinal morphine is an effective analgesic after cesarean delivery, but it has several side effects. The purpose of this study was to compare the prevalence of side effects and the level of analgesia of epidural morphine with two different doses of spinal morphine after elective cesarean delivery. Although rescue analgesics may be required, intrathecal morphine 100 microg is suggested for postoperative analgesia after cesarean delivery.
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Clinical TrialTemperature control and recovery of bowel function after laparoscopic or laparotomic colorectal surgery in patients receiving combined epidural/general anesthesia and postoperative epidural analgesia.
We compared the effects of a laparoscopic (n = 23) versus laparotomic (n = 21) technique for major abdominal surgery on temperature control in 44 patients undergoing colorectal surgery during a combined epidural/general anesthesia. A thoracic epidural block up to T4 was induced with 6-10 mL of 0.75% ropivacaine; general anesthesia was induced with thiopental, fentanyl, and atracurium IV and maintained with isoflurane. Core temperature was measured with a bladder probe and recorded every 15 min after the induction. In both groups, core temperature decreased to 35.2 degrees C (range, 34 degrees C-36 degrees C) at the end of surgery. After surgery, normothermia returned after 75 min (60-120 min) in the Laparoscopy group and 60 min (45-180 min) in the Laparotomy group (P = 0.56). No differences in postanesthesia care unit discharge time were reported between the two groups. The degree of pain during coughing was smaller after laparoscopy than laparotomy from the 24th to the 72nd observation times (P < 0.01). Morphine consumption was 22 mg (2-65 mg) in the Laparotomy group and 5 mg (0-45 mg) in the Laparoscopy group (P = 0.02). The time to first flatus was shorter after laparoscopy (24 h [16-72 h]) than laparotomy (72 h [26-96 h]) (P = 0.0005), and the first intake of clear liquid occurred after 48 h (24-72 h) in the Laparoscopy group and after 96 h (90-96 h) in the Laparotomy group (P = 0.0005). Although laparoscopic surgery provides positive effects on the degree of postoperative pain and recovery of bowel function, the reduction in heat loss produced by minimizing bowel exposure with laparoscopic surgery does not compensate for the anesthesia-related effects on temperature control, and active patient warming must also be used with laparoscopic techniques. ⋯ This prospective, randomized, controlled study demonstrates that laparoscopic colorectal surgery results in less postoperative pain and earlier recovery of bowel function than conventional laparotomy but does not reduce the risk for perioperative hypothermia. Accordingly, active warming must be provided to patients also during laparoscopic procedures.
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Anesthesia and analgesia · Aug 2002
Randomized Controlled Trial Clinical TrialOral tizanidine, an alpha2-adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane in human adults.
Tizanidine, an alpha2-adrenoceptor agonist, has an antinociceptive effect in animals. In humans premedicated with oral tizanidine, the increase in blood pressure associated with laryngoscopy and intubation was attenuated, and the amount of midazolam required for loss of consciousness was significantly reduced. We speculated that the oral administration of tizanidine might reduce the minimum alveolar anesthetic concentration (MAC) of sevoflurane. Fifty-two ASA physical status I-II patients, aged 24-56 yr, were randomly allocated into two groups: a Control group (n = 26) and a Tizanidine group (n = 26). As premedication, the Control group received a placebo, and the Tizanidine group received 4 mg of oral tizanidine 90 min before surgical skin incision. Anesthesia was induced in all patients by using vital capacity rapid inhaled induction with sevoflurane (5%). Loss of consciousness was defined as both the loss of the eyelid reflex and the lack of a response to a verbal command. MAC was determined by a technique adapted from the conventional up-down method for quantal responses. The MAC of sevoflurane was 2.2% +/- 0.2% in the Control group and 1.8% +/- 0.2% in the Tizanidine group (P = 0.0004). The time to loss of consciousness in the Tizanidine group (60.2 +/- 22.5 s) was significantly shorter than that in the Control group (73.7 +/- 26.3 s) (P = 0.03). The oral administration of tizanidine 4 mg successfully reduced the MAC of sevoflurane by 18% in human adults. ⋯ Oral tizanidine (4 mg), an alpha2-adrenoceptor agonist, reduces the minimum alveolar concentration of sevoflurane by 18%.