ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThis multicenter, assessor, blinded, randomized study was conducted to confirm and extend a pilot study in which intramuscular rapacuronium was given to infants and children to confirm efficacy and to evaluate tracheal intubating conditions.MethodsNinety-six pediatric patients were studied in two groups: infants aged 1 to 12 months (n = 46) and children aged 1 to 3 yr (n = 50). Infants received 2.8 mg/kg and children 4.8 mg/kg of intramuscular rapacuronium during 1 minimum alveolar concentration halothane anesthesia. These two groups were studied in three subgroups, depending on the time (1.5, 3, or 4 min) at which tracheal intubation was attempted after the administration of intramuscular rapacuronium into the deltoid muscle. Neuromuscular data collected included onset time, duration of action, and recovery data during train-of-four stimulation at 0.1 Hz. Data were analyzed by the Cochran-Mantel-Haenszel procedure.ResultsThe tracheal intubating conditions were deemed acceptable in 17, 36, and 64% of infants and 20, 47, and 71% of children at 1.5, 3, or 4 min, respectively. The mean values for % of control twitch height (T1) 2 min after rapacuronium in both groups were similar. The mean (SD) time required to achieve more than or equal to 95% twitch depression in infants was 6.0 (3.7)versus5.5 (3.8) min in children.ConclusionsOnly 27% of patients achieved clinically acceptable tracheal intubating conditions at 1.5 or 3 min after administration of 2.8 mg/kg and 4.8 mg/kg rapacuronium during 1 minimum alveolar concentration halothane anesthesia. Tracheal intubation conditions at 4 min were acceptable in 69% of subjects. The duration of action of 4.8 mg/kg of rapacuronium in children was longer than 2.8 mg/kg of rapacuronium in infants.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundMany different doses and administration schemes have been proposed for the use of the antifibrinolytic drug tranexamic acid during cardiac surgery. This study evaluated the effects of the treatment using tranexamic acid during the intraoperative period only and compared the results with the effects of the treatment continued into the postoperative period.MethodsPatients undergoing elective cardiac surgery with use of cardiopulmonary bypass (N = 510) were treated intraoperatively with tranexamic acid and then were randomized in a double-blind fashion to one of three postoperative treatment groups: group A: 169 patients, infusion of saline for 12 h; group B: 171 patients, infusion of tranexamic acid, 1 mg · kg-1· h-1for 12 h; group C: 170 patients, infusion of tranexamic acid, 2 mg · kg-1· h-1for 12 h. Bleeding was considered to be a primary outcome variable. Hematologic data, allogeneic transfusions, thrombotic complications, intubation time, and intensive care unit and hospital stay duration also were evaluated.ResultsNo differences were found among groups regarding postoperative bleeding and outcomes; however, the group treated with 1 mg·kg-1·h-1tranexamic acid required more units of packed red blood cells because of a significantly lower basal value of hematocrit, as shown by multivariate analysis.ConclusionsProlongation of treatment with tranexamic acid after cardiac surgery is not advantageous with respect to intraoperative administration alone in reducing bleeding and number of allogeneic transfusions. Although the prevalence of postoperative complications was similar among groups, there is an increased risk of procoagulant response because of antifibrinolytic treatment. Therefore, the use of tranexamic acid during the postoperative period should be limited to patients with excessive bleeding as a result of primary fibrinolysis.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThe heat–capsaicin sensitization model was developed as a noninvasive and noninjurious human experimental pain model. The sequential application of moderate intensity thermal and topical chemical stimuli produces stable and long-lasting areas of cutaneous secondary hyperalgesia. The aim of the present study was to validate the heat–capsaicin sensitization model as a tool for testing analgesic drug efficacy. Responsivity of model-associated measures was tested with remifentanil, a potent and ultrashort acting &mgr;-opioid agonist.MethodsSensitization was induced by heating forearm skin with a thermode at 45°C for 5 min, immediately followed by application of 0.075% capsaicin cream for 30 min. Sensitization was rekindled four times at 40-min intervals with the thermode at 40°C for 5 min. After each rekindling, areas of secondary hyperalgesia were measured, and the painfulness of thermal stimulation in normal skin with 45°C for 1 min (long thermal stimulation [LTS]) was rated. Before and during the second rekindling, remifentanil 0.10 &mgr;g · kg−1· min−1or saline–placebo was infused for 35 min.ResultsInfusion of remifentanil reduced the areas of secondary hyperalgesia to 29–30% of baseline size compared with 75–83% during placebo. Similarly, remifentanil reduced the painfulness of LTS to 29% of baseline severity compared with 84% during placebo. Areas of secondary hyperalgesia and LTS painfulness returned to baseline levels by the time of the third rekindling, demonstrating rapid disappearance of remifentanil analgesia and possibly transient spontaneous opioid withdrawal hyperalgesia.ConclusionUsing the heat–capsaicin sensitization model, opioid analgesia and suppression of secondary hyperalgesia was reliably demonstrated without skin injury.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundDehydrofluorination of sevoflurane by carbon dioxide absorbents in anesthesia machines produces compound A, which is nephrotoxic in rats. Several clinical studies indicate that prolonged low-flow sevoflurane anesthesia is associated with an increased urinary excretion of biochemical markers, such as protein. Probenecid, a competitive inhibitor of organic anion transport, diminishes compound A nephrotoxicity in rats. The purpose of the present study was to examine the effects of low- and high-flow sevoflurane anesthesia on urinary excretion of biochemical markers in humans and to examine the effects of probenecid on urinary excretion of these markers.MethodsElective surgical patients (n = 64) were assigned to four groups (n = 16 each): low-flow sevoflurane plus probenecid (LSP), low-flow sevoflurane (LS), high-flow sevoflurane plus probenecid (HSP), and high-flow sevoflurane (HS). Probenecid (2.0 g) was administered orally 2 h before the induction of anesthesia in both the LSP and HSP groups. Nothing was administered orally 2 h before the induction of anesthesia in either the LS or HS groups. All patients underwent prolonged low-flow (1 l/min) or high-flow (6 l/min) sevoflurane anesthesia. Urinary excretion of protein, albumin, &bgr;2-microglobulin, glucose, andN-acetyl-&bgr;-d-glucosaminidase was measured for up to 7 days postoperatively.ResultsSevoflurane doses were similar in all four groups. There were no differences in blood urea nitrogen, creatinine, or creatinine clearance among the four groups after anesthesia. Average values for urinary excretion of protein, &bgr;2-microglobulin, andN-acetyl-&bgr;-d-glucosaminidase in the LS group were significantly higher than those in the other groups (LSP, HSP, HS;P< 0.05). There was no significant difference between the LS and LSP groups in average values for urinary excretion of albumin and glucose, although there were significant differences between the LS and both high-flow sevoflurane groups (HSP, HS).ConclusionsLow-flow sevoflurane, which produces a sevenfold higher compound A exposure than high-flow sevoflurane, resulted in significant increases of several biochemical markers in half of the patients. Probenecid appears to provide protection against these renal effects.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundDepression of spinal cord motoneuron excitability has been proposed to contribute to surgical immobility. The H-reflex, which measures &agr;-motoneuron excitability, is depressed by volatile anesthetics, whereas the action of propofol is unknown. The objective of this study was to determine the effects of propofol anesthesia on the H-reflex.MethodsIn 13 patients (group 1), H-reflex was measured before (T0), 3 min after (T1), and 10 min after (T2) a 2-mg/kg bolus dose of propofol, followed by an infusion of 10 mg · kg−1· h−1. Ten patients (group 2) were studied when propofol was givenviaa programmable pump set to a propofol blood concentration of 6 &mgr;g/ml, and 10 patients (group 3) were studied with the pump set to 9 &mgr;g/ml. Latencies and amplitudes of H-reflexes (H0, H1, H2) and M-responses (M0, M1, M2) of the soleus muscle were recorded, and H/M ratios (H0/M0, H1/M1, H2/M2) were calculated.ResultsIn group 1, H-reflex amplitudes and the H/M ratio were diminished after induction with propofol (H0vs.H1,P= 0.033; H0/M0vs.H1/M1,P= 0.042). After 10 min of propofol infusion, the H2/M2ratio was still decreased versus H0/M0(P= 0.031). In group 2, no difference was detected. In group 3, propofol depressed H-reflex amplitudes at T2(H0vs.H2,P< 0.01), and amplitudes were also lower at T2than at T1(H1vs.H2,P< 0.01). In this group, the H/M ratio decreased from T0to T2(H0/M0vs.H2/M2,P< 0.002).ConclusionsDuring steady state conditions using propofol as the sole agent, a depression of the H-reflex is observed only at a high blood concentration of 9 &mgr;g/ml. The authors suggest that immobility during propofol anesthesia is not caused by a depression of spinal motoneuron circuit excitability.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThe value of exercise electrocardiography in the prediction of perioperative cardiac risk has yet to be defined. This study was performed to determine the predictive value of exercise electrocardiography as compared with clinical parameters and resting electrocardiography.MethodsA total of 204 patients at intermediate risk for cardiac complications prospectively underwent exercise electrocardiography before noncardiac surgery. Of these, 185 were included in the final evaluation. All patients underwent follow-up evaluation postoperatively by Holter monitoring for 2 days, daily 12-lead electrocardiogram, and creatine kinase, creatine kinase MB, and troponin-T measurements for 5 days. Cardiac events were defined as cardiac death, myocardial infarction, minor myocardial cell injury, unstable angina pectoris, congestive heart failure, and ventricular tachyarrhythmia. Potential risk factors for an adverse event were identified by univariate and multivariate logistic regression analysis.ResultsPerioperative cardiac events were observed in 16 patients. There were 6 cases of myocardial infarction and 10 cases of myocardial cell injury. The multivariate correlates of adverse cardiac events were definite coronary artery disease (odds ratio, 8.8; 95% confidence interval [CI], 1.1–73.1;P= 0.04), major surgery (odds ratio, 4.7; 95% CI, 1.3–16.3;P= 0.02), reduced left ventricular performance (odds ratio, 2.0; 95% CI, 1.1–3.8;P= 0.03), and ST-segment depression of 0.1 mV or more in the exercise electrocardiogram (odds ratio, 5.2; 95% CI, 1.5–18.5;P= 0.01). A combination of clinical variables and exercise electrocardiography improved preoperative risk stratification.ConclusionsThis prospective study shows that a ST-segment depression of 0.1 mV or more in the exercise electrocardio-gram is an independent predictor of perioperative cardiac complications.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundRecirculatory models are capable of accurately describing first-pass pharmacokinetics and the influence of cardiac output (CO), which is important for drugs with a fast onset of effect. The influence of CO on pharmacokinetic and pharmacodynamic parameters of rocuronium in patients was evaluated using a recirculatory pharmacokinetic model.MethodsFifteen patients were included to study rocuronium pharmacokinetics and pharmacodynamics. Bolus doses of rocuronium (0.35 mg/kg) and indocyanine green (25 mg) were injected simultaneouslyviaa peripheral intravenous catheter. Blood samples were taken for 240 min from the radial artery. The force of contraction of the adductor pollicis after a train-of-four at 2 Hz every 12 s was measured. Arterial concentration–time curves of rocuronium and indocyanine green were analyzed using a recirculatory model. Pharmacodynamics were described using a sigmoid maximum effect (Emax) model.ResultsThe CO of the patients varied from 2.43 to 5.59 l/min. Total distribution volume of rocuronium was 17.3 ± 4.8 l (mean ± SD). The CO showed a correlation with the fast tissue clearance (ClT_f; r2= 0.51), with the slow tissue clearance (ClT_s; r2= 0.31) and with the mean transit times of rocuronium except for the mean transit time of the slow tissue compartment. The blood–effect site equilibration constant (ke0) was strongly correlated with CO (r2= 0.70).ConclusionsCardiac output influences the pharmacokinetics, including ke0, for rocuronium in patients. For drugs with a fast onset of effect, a recirculatory model, which includes CO, can give a good description of the relation between concentration and effect, in contrast to a conventional compartmental pharmacokinetic model.

ISSN:0003-3022    

出版商:OVID    

年代:2001

数据来源: OVID