Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. I. Emergence and recovery profiles.
Pyloric stenosis is sometimes associated with hemodynamic instability and postoperative apnea. In this multicenter study we examined the hemodynamic response and recovery profile of remifentanil and compared it with that of halothane in infants undergoing pyloromyotomy. After atropine, propofol, and succinylcholine administration and tracheal intubation, patients were randomized (2:1 ratio) to receive either remifentanil with nitrous oxide and oxygen or halothane with nitrous oxide and oxygen as the maintenance anesthetic. Pre- and postoperative pneumograms were done and evaluated by an observer blinded to the study. Intraoperative hemodynamic data and postanesthesia care unit (PACU) discharge times, PACU recovery scores, pain medications, and adverse events (vomiting, bradycardia, dysrhythmia, and hypoxemia) were recorded by the study's research nurse. There were no significant differences in patient age or weight between the two groups. There were no significant differences in hemodynamic values between the two groups at the various intraoperative stress points. The extubation times, PACU discharge times, pain medications, and adverse events were similar for both groups. No patient anesthetized with remifentanil who had a normal preoperative pneumogram had an abnormal postoperative pneumogram, whereas three patients with a normal preoperative pneumogram who were anesthetized with halothane had abnormal pneumograms after. ⋯ The use of ultra-short-acting opioids may be an appropriate technique for infants less than 2 mo old when tracheal extubation after surgery is anticipated.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. II. Perioperative breathing patterns in neonates and infants with pyloric stenosis.
Although former preterm birth infants are at risk for postoperative apnea after surgery, it is unclear whether the same is true of full-term birth infants. We evaluated the incidence of apnea in 60 full-term neonates and infants undergoing pyloromyotomy both before and after anesthesia. All subjects were randomized to a remifentanil- or halothane-based anesthetic. Apnea was defined by the presence of prolonged apnea (>15 s) or frequent brief apnea, as observed on the pneumocardiogram. Apnea occurred before surgery in 27% of subjects and after surgery in 16% of subjects, with no significant difference between subjects randomized to remifentanil or halothane anesthesia. This apnea was primarily central in origin, occurred throughout the recording epochs, and was associated with severe desaturation in some instances. Of the subjects with normal preoperative pneumocardiograms, new onset postoperative apnea occurred in 3 (23%) of 13 subjects who received halothane-based anesthetics versus 0 (0%) of 22 subjects who received remifentanil-based anesthetics (P = 0.04). Thus, postoperative apnea can follow anesthesia in otherwise healthy full-term infants after pyloromyotomy and is occasionally severe with desaturation. New-onset postoperative apnea was not seen with a remifentanil-based anesthetic. ⋯ Abnormal breathing patterns can follow anesthesia in infants after surgical repair of pyloric stenosis. Occasionally, these patterns can be associated with desaturation. New-onset postoperative apnea was not seen with a remifentanil-based anesthetic.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialPreoperative oral B vitamins prevent nitrous oxide-induced postoperative plasma homocysteine increases.
Nitrous oxide increases total homocysteine (tHcy) plasma levels, which are associated with an increase in perioperative myocardial ischemia. We designed this study to determine whether oral B vitamins, which are cofactors in homocysteine metabolism, can prevent nitrous oxide anesthesia-induced tHcy increases in patients undergoing elective surgery scheduled to last longer than 3 h. Fifty-three patients presenting for elective revision knee or hip arthroplasty received in random, double-blinded fashion oral vitamin B complex (folate 2.5 mg, B(6) 25 mg, and B(12) 500 microg) or placebo daily for 1 wk before surgery. Anesthesia was induced with propofol and maintained with an opioid, isoflurane, and nitrous oxide/oxygen (inspired nitrous oxide >50%). Blood samples for measurement of tHcy concentration were obtained at study enrollment, before induction, on arrival in the postanesthesia care unit, and on Day 5. Fourteen patients had their surgery rescheduled after taking their vitamins and were removed from the study. The Placebo group had a mean increase in tHcy concentration from baseline of 15% +/- 31% compared with the Vitamin group, which had an initial decrease of 9.1% +/- 11% (P = 0.035). This was maintained throughout the 5-day study period. The use of an oral B vitamin complex prevented the increase in postoperative tHcy by nitrous oxide. ⋯ The use of nitrous oxide anesthesia increases postoperative homocysteine concentrations and associated myocardial ischemia. This study indicates that a 1-wk course of oral B vitamins can prevent the increase in homocysteine from nitrous oxide, and, by implication, myocardial ischemia as well.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialEsmolol promotes electroencephalographic burst suppression during propofol/alfentanil anesthesia.
This study examined the effects of an esmolol infusion on the electroencephalogram during propofol/alfentanil IV anesthesia. After informed consent, 20 patients were randomly assigned into four groups on the basis of two target alfentanil concentrations (alfentanil 50 or 150 ng/mL) and of a saline or esmolol infusion. Bispectral index (BIS), burst suppression ratio (SR), and physiologic variables were continuously monitored. A 30-min blinded infusion of saline or esmolol was started after establishing a stable baseline and followed by a washout period. The electroencephalogram was significantly suppressed by esmolol (BIS, 37 +/- 6 to 22 +/- 6, 40% decrease [mean +/- SD]; SR, 5 +/- 7 to 67 +/- 23, 13.4-fold increase) compared with baseline in the small-dose alfentanil groups. Discontinuation of esmolol reversed the response. BIS and SR were unaffected by placebo infusion. Twelve-minute to 16-min hysteresis between esmolol administration and the onset of half-maximal cortical suppression was observed. Physiologic variables and serum propofol and alfentanil concentrations were not significantly altered by esmolol. Although the mechanism remains unclear, significant cortical depression and the onset of burst suppression during a stable, computer-controlled propofol/alfentanil anesthetic was associated with esmolol infusion. ⋯ This study demonstrated the suppression of cerebral cortical electrical activity after blinded esmolol infusion during propofol/alfentanil anesthesia. A significant lag was noted between infusion and half-maximal effect (12-16 min). Whether esmolol, a metabolite, or a secondary process was responsible for this cortical suppression remains unknown and requires further study.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Comparative Study Clinical TrialThe continuous recording of blood pressure in patients undergoing carotid surgery under remifentanil versus sufentanil analgesia.
We compared the hemodynamic stability during carotid endarterectomy of remifentanil with that of sufentanil anesthesia. Fifty-six patients were randomly assigned into Remifentanil (n = 27) or Sufentanil (n = 29) groups. In the Remifentanil group, IV propacetamol (2 g) and morphine (0.1 mg/kg) were infused 30 min before skin closure. In the Sufentanil group, patients received 2 g propacetamol. Beat-to-beat recordings of systolic arterial blood pressure (SBP) and heart rate (HR) were stored on a computer. The maximum and minimum values of BP and HR after induction, at intubation, during the surgical procedure, and after the operation and the coefficients of variation of SBP and HR were used as indices of hemodynamic stability. The coefficients of variation of SBP and HR were similar in both groups during and after surgery. However, at intubation, maximal SBP was higher in the Sufentanil group (P < 0.05). Decreased propofol doses and isoflurane end-tidal concentrations were used in the Remifentanil group. At recovery, a similar profile of SBP and HR was found in both groups. We conclude that intra- and posthemodynamic stability was similar with remifentanil or sufentanil in patients undergoing carotid endarterectomy. However, remifentanil was more effective for blunting the increase in SBP at intubation without increasing the blood pressure-decreasing effect of induction. Intraoperative remifentanil use was associated with a decreased amount of hypnotic drug administered. ⋯ Beat-to-beat recordings of heart rate and blood pressure in patients undergoing carotid surgery revealed that hemodynamic stability was similar with remifentanil or sufentanil anesthesia both during and after surgery. Remifentanil was more effective in limiting the increase in blood pressure associated with intubation without increasing the blood pressure-lowering effect of induction or the blood pressure response to recovery.