ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundPiritramide is a synthetic opioid used for post‐operative analgesia in several European countries. The authors present a mixed‐effects model of its population pharmacokinetics in patients undergoing surgery.MethodsAfter institutional approval and informed patient consent was obtained, 29 patients who were classified as American Society of Anesthesiologists physical status I or II and aged 21‐82 yr were enrolled in the study. They received 0.2 mg/kg piritramide as an intravenous bolus before anesthesia was induced. Central venous blood samples were drawn for as long as 48 h after administration of the drug. The plasma concentration of piritramide was determined by gas chromatography. The concentration‐time data were analyzed by mixed‐effects modeling. Target‐controlled infusions and intermittent bolus regimens were simulated to identify a regimen suitable for patient‐controlled analgesia based on population pharmacokinetics and published pharmacodynamic data.ResultsThe pharmacokinetics of piritramide were described adequately by a linear three‐compartment model. Patient age and weight were significant covariates. The values of the pharmacokinetic parameters are: V1= 50.5 [1], V2= 150 [middle dot] (1 + 9.32 [middle dot] 10‐3[middle dot] (age ‐ 47 yr)) [1], V3= 212 [middle dot] (1 + 6.37 [middle dot] 10‐3[middle dot] (age ‐ 47 yr)) [1], Cl1= 0.56 [middle dot] (1 ‐ 6.14 [middle dot] 10‐3[middle dot] (age ‐ 47 yr)) [1/min], Cl2= 8.25 [middle dot] (1 + 2.02 [middle dot] 10‐2[middle dot] (Wt ‐ 74 kg)) [1/min], Cl3= 0.80 [1/min]. The age of 47 yr and the weight of 74 kg refer to the median values for these factors in the patients studied. Rapid distribution, slow distribution, and elimination half‐lives for the median patient are 0.05, 1.34, and 10.43 h, respectively. The context‐sensitive half‐time after a 24‐h infusion is predicted at 10.5 h in a 75‐yr‐old patient compared with 7 h for the median patient.ConclusionsPiritramide is distributed extensively and eliminated slowly. The pharmacokinetic profile of the drug allows for intermittent bolus administration even when constant effect compartment concentrations are desirable, e.g., for PLA.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundNondepolarizing muscle relaxants differ in their time course at the laryngeal adductors and the adductor pollicis, a result of differences in equilibration delays between plasma and effect sites, the sensitivity of each muscle to the relaxant, and the steepness of the concentration‐effect relation at each muscle (the Hill factor). To determine whether similar differences exist for rapacuronium, a muscle relaxant with rapid onset and offset, the authors determined its pharmacodynamic characteristics.MethodsThe twitch tensions of the adductor pollicis and the laryngeal adductors (via a tracheal tube cuff positioned at the vocal cords) were measured in 10 volunteers who were anesthetized with propofol. Rapacuronium, 1.5 mg/kg, was given and blood samples were collected. A semiparametric effect compartment pharmacodynamic model was fit to values for rapacuronium plasma concentrations and twitch tension of the adductor pollicis and laryngeal adductors.ResultsEquilibration between the rapacuronium plasma concentration and both effect sites was rapid (typical values for the rate constant for equilibration between plasma and the effect site are 0.405 per min for the adductor pollicis and 0.630 per min for the laryngeal adductors) and was more rapid at the laryngeal adductors than at the adductor pollicis (ratio, 1.59 +/− 0.16; mean +/− SD). The steady state rapacuronium plasma concentration that depressed twitch tension by 50% and the Hill factor were similar for the two muscles.ConclusionsThe rapid onset and offset of rapacuronium can be explained by the rapid equilibration between concentrations in plasma and at the effect site. Unlike the finding for other nondepolarizing muscle relaxants, the laryngeal muscles are not resistant to rapacuronium.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundBecause renal function affects the elimination of muscle relaxants, each new muscle relaxant must be evaluated in patients with renal failure. Accordingly, the neuromuscular effects and pharmacokinetics of rapacuronium were identified in patients with renal failure.MethodsRapacuronium (1.5 mg/kg) was administered to 10 healthy volunteers and 10 patients with renal failure who were undergoing non‐transplant surgery, were 18‐45 yr old, and were anesthetized with propofol. The adductor pollicis muscle twitch tension was monitored. Plasma samples were obtained frequently for a period of 8 h to measure the concentrations of ORG9487 and its metabolite, ORG9488. Pharmacokinetic parameters were determined using mixed‐effects modeling.ResultsOne patient was excluded from analysis because he was taking phenytoin chronically. Twitch depression at 1 min was less in patients than in healthy volunteers (median values: 92% in patients, 99% in volunteers). The times to 90% and peak twitch depression; to 10%, 25%, and 75% twitch recovery; and to 70% and 80% train‐of‐four ratios were similar in volunteers and patients. Rapacuronium's clearance was 32% less in patients with renal failure; in both groups, clearance decreased 0.909% per year of age compared with the value in a 30 yr old. The steady state distribution volume was 14% less in women than in men and 16% less in patients than in volunteers. For ORG9488, clearance was 85% less in patients than in volunteers.ConclusionsThe neuromuscular effects of a single dose of rapacuronium are affected minimally by renal failure. However, the decreased clearance of rapacuronium and its potent metabolite in renal failure suggests that repeated dosing of rapacuronium may lead to prolonged effects in patients with renal failure.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundWhether anesthetic agents administered during gamete intrafallopian transfer (GIFT) affect reproductive outcome is controversial. This multicenter pilot trial and survey had two purposes: to evaluate the effect of propofol, nitrous oxide, midazolam, and isoflurane on pregnancy outcome after GIFT, and to determine if a larger prospective, randomized study is warranted.MethodsA written invitation was mailed to all 50 fertility programs in the United States that are members of the Society for Assisted Reproductive Technology and perform more than 30 GIFT procedures per year. They were invited to contribute information from the medical records of women who underwent GIFT during the calendar years 1993 and 1994. They were asked to document whether propofol, nitrous oxide, midazolam, a potent inhaled anesthetic agent was used during the GIFT procedure; if the woman became pregnant; and if she delivered at least one live neonate.ResultsSeven medical centers participated and contributed data from 455 women. The clinical pregnancy rate (number of pregnancies/total number of GIFT procedures) and the delivery rate (number of women who delivered at least one live baby/total number of GIFT procedures) were 35% and 32%, respectively. A statistically significant difference could not be found in the clinical pregnancy or delivery rates between those women who received propofol, nitrous oxide, midazolam, or isoflurane during GIFT and those who did not.ConclusionsNo agent‐related differences in pregnancy rates were found when propofol, nitrous oxide, isoflurane, or midazolam was used as part of the anesthetic technique for GIFT. Therefore, a more extensive prospective trial does not appear to be warranted.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundPatients with cirrhosis have a reduced life expectancy. Anesthesia and surgery have been associated with clinical decompensation in patients with cirrhosis.MethodsThe authors retrospectively reviewed the records of all patients with the diagnosis of cirrhosis who underwent any surgical procedure under anesthesia at their institution between January 1980 and January 1991 (n = 733). Univariate and multivariate analyses were used to identify the variables associated with perioperative complications and short‐ and long‐term survival.ResultsThe perioperative mortality rate (within 30 days of surgery) was 11.6%. The perioperative complication rate was 30.1%. Postoperative pneumonia was the most frequent complication. Multivariate factors that were associated with perioperative complications and mortality included male gender, a high Child‐Pugh score, the presence of ascites, a diagnosis of cirrhosis other than primary biliary cirrhosis (especially cryptogenic cirrhosis), an elevated creatinine concentration, the diagnosis of chronic obstructive pulmonary disease, preoperative infection, preoperative upper gastrointestinal bleeding, a high American Society of Anesthesiologists physical status rating, a high surgical severity score, surgery on the respiratory system, and the presence of intraoperative hypotension.ConclusionRisk factors have been identified for patients with cirrhosis who undergo anesthesia and surgery.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe goal of this project was to study the frequency and natural history of perioperative ulnar neuropathy.MethodsA prospective evaluation of ulnar neuropathy in 1,502 adult patients undergoing noncardiac surgical procedures was performed. Patients were assessed with a standard questionnaire and neurologic examination before surgery, daily during hospitalization in the first week after surgery, and by telephone if they were discharged before 1 postoperative week. Patients in whom ulnar neuropathy developed were followed for 2 yr.ResultsUlnar neuropathy developed in seven patients (0.5%; 95% confidence interval, 0.2% to 1.0%). Six of the seven patients were men. Symptoms of ulnar neuropathy began 2‐7 days after surgery. Manifestations were mild and confined to sensory deficits in six patients. Symptoms resolved in four patients within 6 weeks. The remaining three patients had residual symptoms 2 yr later.ConclusionsIn this surgical population, ulnar neuropathy was an infrequent complication. It occurred primarily in men who were 50‐75 yr old and was not symptomatic until several days after surgery. Gender‐dependent differences in the anatomy of the ulnar nerve and related structures at the elbow may serve as risk factors for ulnar neuropathy in patients having surgery.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

BackgroundThe effects of sevoflurane on the electrophysiologic properties of the human heart are unknown. This study evaluated the effects of sevoflurane on the electrophysiologic properties of the normal atrioventricular conduction system, and on the accessory pathways in patients with Wolff‐Parkinson‐White syndrome, to determine its suitability as an anesthetic agent for patients undergoing ablative procedures.MethodsFifteen patients with Wolff‐Parkinson‐White syndrome undergoing elective radiofrequency catheter ablation were studied. Anesthesia was induced with alfentanil (20‐50 [micro sign]g/kg) and midazolam (0.15 mg/kg), and vecuronium (20 mg) and maintained with alfentanil (0.5 to 2 [micro sign]g [middle dot] kg‐1[middle dot] min‐1) and midazolam (1 or 2 mg every 10‐15 min, as required). An electrophysiologic study measured the effective refractory period of the right atrium, atrioventricular node, and accessory pathway; the shortest conducted cycle length of the atrioventricular node and accessory pathway during atrial pacing; the effective refractory period of the right ventricle and accessory pathway; and the shortest retrograde conducted cycle length of the accessory pathway during ventricular pacing. Parameters of sinoatrial node function included sinus node recovery time, corrected sinus node recovery time, and sinoatrial conduction time. Intraatrial conduction time and the atrial‐His interval were also measured. Characteristics of induced reciprocating tachycardia, including cycle length, atrial‐His, His‐ventricular, and ventriculoatrial intervals, also were measured. Sevoflurane was administered to achieve an end‐tidal concentration of 2% (1 minimum alveolar concentration), and the study measurements were repeated.ResultsSevoflurane had no effect on the electrophysiologic parameters of conduction in the normal atrioventricular conduction system or accessory pathway, or during reciprocating tachycardia. However, sevoflurane caused a statistically significant reduction in the sinoatrial conduction time and atrial‐His interval, but these changes were not clinically important. All accessory pathways were successfully identified and ablated.ConclusionsSevoflurane had no effect on the electrophysiologic nature of the normal atrioventricular or accessory pathway and no clinically important effect on sinoatrial node activity. It is therefore a suitable anesthetic agent for patients undergoing ablative procedures.

ISSN:0003-3022    

出版商:OVID    

年代:1999

数据来源: OVID