Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialSevoflurane or halothane anesthesia: can we tell the difference?
This study was performed to evaluate the ability of anesthesiologists to differentiate between sevoflurane, a newer, more expensive anesthetic, and halothane. A total of 113 assessments were made by 36 anesthesiologists on 58 children, aged 6 mo to 6 yr, scheduled for bilateral myringotomy and tube placement. All patients received midazolam (0.5 mg/kg per os) approximately 30 min before the induction of anesthesia. Sevoflurane or halothane was randomly selected for anesthetic induction and maintenance. The anesthesiologists, who were unaware of the anesthetic being used, were asked to identify the anesthetic based on clinical signs and to assess the quality of induction, speed of induction, and speed of emergence using a visual analog scale (VAS; minimum score = 0, maximum score = 100). The anesthesiologists correctly identified the anesthetic only 56.6% of the time. This was not significantly different from the 50% that would result from random guessing (P = 0.08). Further, there were no significant differences in VAS scores between the two groups. This study suggests that in premedicated pediatric patients undergoing brief surgical procedures, anesthesiologists cannot correctly differentiate between sevoflurane and halothane. The lack of significant differences in VAS scores suggests that the speed of induction, the speed of emergence, and the quality of induction are similar under these clinical conditions. Any purported benefits of sevoflurane seem to be of minor consequence under the circumstances studied. ⋯ When the anesthetic halothane or sevoflurane is administered in a blind, randomized fashion, anesthesiologists could not reliably identify which drug was being used to anesthetize children for a brief surgical procedure. These results suggest that the differences between the two drugs in clinical practice are small and may not justify the additional cost of sevoflurane.
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Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Clinical TrialIntrathecal sufentanil, fentanyl, or placebo added to bupivacaine for cesarean section.
We compared the effects of intrathecal sufentanil 2.5 and 5 microg, fentanyl 10 microg, and placebo when administered together with hyperbaric bupivacaine 0.5% 12.5 mg for cesarean section. The study was performed in a randomized, double-blind fashion in 80 (20 per group) healthy, full-term parturients presenting for elective cesarean section. Postoperative pain was assessed using the visual analog scale (VAS). Duration of complete analgesia was defined as the time from the intrathecal injection to VAS score > 0. Duration of effective analgesia was defined as the time to VAS score > or = 4. No patient experienced intraoperative pain. Complete analgesia was prolonged in all groups receiving opioids. Effective analgesia was prolonged and the 0- to 6-h intravenous opioid requirements were lower in the groups receiving sufentanil compared with those receiving fentanyl and placebo. The need for intraoperative antiemetic medication was greater in the placebo group. Pruritus was a frequent and dose-related side effect in the groups receiving sufentanil. There were no differences in umbilical cord blood gases or neonatal Apgar scores and neurological and adaptive capacity scores among the groups. In conclusion, the addition of sufentanil or fentanyl improved the quality of subarachnoid block compared with placebo. The duration of action was longer for sufentanil than fentanyl. ⋯ Small doses of fentanyl or sufentanil (synthetic opioids) added to bupivacaine (local anesthetic) for spinal anesthesia for cesarean section reduce the need for intraoperative antiemetic medication and increase the duration of analgesia in the early postoperative period compared with placebo.
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Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialEpidural analgesia and intravenous patient-controlled analgesia result in similar rates of postoperative myocardial ischemia after aortic surgery.
To assess the role of postoperative analgesia on myocardial ischemia after aortic surgery, we compared intravenous patient-controlled analgesia (PCA) with thoracic epidural analgesia (TEA). One hundred twenty-four patients were prospectively randomized to the PCA or TEA group. In the TEA group, a T6-7 or T7-8 epidural catheter was inserted before the induction of general anesthesia. Within 1 h of the end of surgery, analgesia and 24-h two-channel Holter monitoring were begun. Myocardial ischemia was defined as ST segment depression > or = 1 mm, 0.06 s after the J point, and lasting for more than 1 min. In the PCA group, a bolus of morphine, 0.05 mg/kg, was given, followed by 0.02 mg/kg of morphine on demand every 10 min. Bupivacaine 0.125% and fentanyl 10 microg/mL was used in the TEA group. Analgesics were titrated to maintain a visual analog scale score < or = 3. The overall incidence of myocardial ischemia was 18.4%-18.2% for TEA and 18.6% for PCA (P = not significant). There were no differences between the groups in the total duration of ischemia per patient (22.2 +/- 119.8 min for TEA and 20.5 +/- 99 min for PCA) and the number of episodes per patient (0.69 +/- 2.1 for TEA and 1.2 +/- 4.9 for PCA). Twenty-three patients had an adverse cardiac outcome, although there were no differences between the groups. The postoperative pain control was superior with TEA. In these patients undergoing elective aortic surgery, the use of postoperative TEA did not result in a lower incidence of early myocardial ischemia compared with intravenous PCA with morphine, despite better analgesia with TEA. ⋯ Postoperative myocardial ischemia is associated with adverse cardiac outcome. Using Holter monitoring after aortic surgery, this study shows that the use of thoracic epidural analgesia with bupivacaine and fentanyl did not result in a lower incidence of myocardial ischemia compared with intravenous patient-controlled analgesia with morphine.
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Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Clinical TrialThe choice of anesthetic maintenance technique influences the antiinflammatory cytokine response to abdominal surgery.
Outcome in some diseases is determined by the relationship between pro- and antiinflammatory cytokines. Surgery may also provoke a cytokine response, which has both pro- and antiinflammatory components. The aim of this study was to ascertain whether anesthetic technique can modify the balance of cytokines associated with abdominal surgery. Twenty patients scheduled to undergo elective abdominal hysterectomy were randomly allocated to receive maintenance of anesthesia with isoflurane (IH group) or propofol (IV group). Venous blood samples for measurement of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-10 (IL-10), and interleukin-1 receptor antagonist (IL-1ra) were taken before the induction of anesthesia and at set intervals until 24 h postoperatively. TNF-alpha levels remained low throughout the study; however, all patients showed a significant postoperative increase in IL-6, IL-10, and IL-1ra (P < 0.05). Levels of the proinflammatory cytokine IL-6 were similar in both groups, whereas the antiinflammatory cytokine IL-10 was higher in the IV group at 4 h postoperatively (P < 0.02). The difference between groups in terms of IL-1ra production just failed to reach significance (P < 0.06). We conclude that the cytokine response to abdominal surgery has both pro- and antiinflammatory components and that the choice of anesthetic may modify the balance of these cytokines. ⋯ This study demonstrates that in addition to the widely reported proinflammatory cytokine response, elective abdominal surgery provokes an antiinflammatory response, which may be enhanced by total intravenous anesthesia. The ability of anesthetics to modify the cytokine response to surgery may have therapeutic potential.
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Anesthesia and analgesia · Dec 1997
Randomized Controlled Trial Comparative Study Clinical TrialContribution of the spinal cord to arousal from inhaled anesthesia: comparison of epidural and intravenous fentanyl on awakening concentration of isoflurane.
To investigate the contribution of modulation of afferent nociceptive inputs by an opioid in the spinal cord to arousal from inhaled anesthesia, we determined the awakening concentration of isoflurane in 50 unpremedicated patients scheduled for abdominal hysterectomy. Patients were assigned randomly to three groups. Group I received bolus injections of both epidural and intravenous (I.V.) saline, followed by both epidural and I.V. infusions at the rate of 0.2 mL x kg(-1) h(-1). Group II received an I.V. injection of fentanyl 2 microg/kg, followed by an infusion at the rate of 25 ng x kg(-1) x min(-1), and Group III received an epidural injection and infusion in the same administration regimen as Group II. Anesthesia was induced with and maintained by isoflurane in an air/oxygen mixture (fraction of inspired oxygen = 0.5) with no adjuvant drugs. The study drug was administered at the start of retroperitoneal suturing. The awakening concentrations of isoflurane in Groups I, II, and III (mean +/- SD) were 0.32% +/- 0.07%, 0.31% +/- 0.06%, and 0.24% +/- 0.06%, respectively. At that time, plasma fentanyl concentrations in Groups II and III were 1.12 +/- 0.09 ng/mL and 0.65 +/- 0.04 ng/mL, respectively. Epidural fentanyl infusion reduced the awakening concentration of isoflurane more (P < 0.01) than I.V. fentanyl infusion, despite the lower plasma concentration (P < 0.01) in the epidural group. These findings suggest that epidural fentanyl delays arousal from inhaled anesthesia by modulating the afferent nociceptive inputs in the spinal cord. The spinal cord may contribute to arousal from inhaled anesthesia through the regulation of afferent inputs by opioids along with the supraspinal region of the central nervous system (CNS), even if the effects of subarachnoid fentanyl on the higher CNS via the cephalad migration is taken into consideration. ⋯ The present study revealed that the spinal cord, the lower level of central nervous system, contributed to arousal from general anesthesia, along with the higher central nervous system, by comparing the concentrations of an inhaled anesthetic, isoflurane, in the expiration of patients receiving systemic or regional administration of an opioid, fentanyl.