Acetazolamide improves cerebral oxygenation during exercise at high altitude.

Vuyk, Jaap, Jan Van Den Bos, Kees Terhell, Rene De Bos, Ad Vletter, Pierre Valk, Martie Van Beuzekom, Jack Van Kleef, and Albert Dahan. Acetazolamide improves cerebral oxygenation during exercise at high altitude. High Alt.

The effect of age on the systemic absorption and systemic disposition of ropivacaine after epidural administration.

Knowledge about the systemic absorption and disposition of ropivacaine after epidural administration is important in regard to its clinical profile and the risk of systemic toxicity. We investigated the influence of age on the pharmacokinetics of ropivacaine 1.0% after epidural administration, using a stable-isotope method.

Gender differences in the pharmacokinetics of propofol in elderly patients during and after continuous infusion.

Differences in the pharmacokinetics of propofol between male and female patients during and after continuous infusion have not been described in detail in patients aged 65 yr and older. To increase our insight into the pharmacokinetics of propofol in this patient population and to obtain pharmacokinetic parameters applicable in target controlled infusion (TCI), the pharmacokinetics of propofol during and after continuous infusion were studied in 31 ASA class 1 and 2 patients, aged 65-91 yr, scheduled for general surgery. Patients received propofol 1.

Target-controlled infusion of alfentanil for postoperative analgesia: contribution of plasma protein binding to intra-patient and inter-patient variability.

We have examined the influence of plasma protein binding on inter-individual and intra-individual variability in the effective postoperative analgesic concentration (EAC) of alfentanil and on the performance of the target-controlled infusion system used. Ten patients received standardized anaesthesia and target-controlled alfentanil for postoperative analgesia. Analgesia was assessed using a visual analogue scale (VAS).

Effect-site modelling of propofol using auditory evoked potentials.

Auditory evoked potentials (AEP) were used to monitor central nervous system effects during induction and recovery from anaesthesia produced by infusion of propofol 30 mg kg-1 h-1 in 22 healthy male patients. Non-parametric and parametric modelling techniques were used successfully to calculate the parameter keo which linked pharmacokinetic with pharmacodynamic aspects of drug action in only 15 of the study patients. In the non-parametric analysis, keo was found to have a mean value of 0.

Recirculatory and compartmental pharmacokinetic modeling of alfentanil in pigs: the influence of cardiac output.

Background: Cardiac output (CO) is likely to influence the pharmacokinetics of anesthetic drugs and should be accounted for in pharmacokinetic models. The influence of CO on the pharmacokinetic parameters of alfentanil in pigs was evaluated using compartmental and recirculatory models.

Methods: Twenty-four premedicated pigs were evaluated during halothane (0.

Pharmacokinetics of prilocaine after intravenous administration in volunteers: enantioselectivity.

Background: Prilocaine exists in two stereoisomeric configurations, the enantiomers S(+)- and R(-)-prilocaine. The drug is clinically used as the racemate. This study examined the pharmacokinetics of the enantiomers after intravenous administration of the racemate.

Alfentanil as an adjuvant to epidural bupivacaine in the management of postoperative pain after laparotomies: lack of evidence of spinal action.

Unlabelled: In this double-blind study, we compared the efficacy of epidural versus i.v. administration of alfentanil in combination with small-dose bupivacaine for postoperative pain relief.

Target-controlled infusion of alfentanil for postoperative analgesia: a feasibility study and pharmacodynamic evaluation in the early postoperative period.

We have examined the feasibility of target-controlled infusion of alfentanil (TCIA) and the pharmacodynamics of alfentanil in the early postoperative period. Patients were allocated randomly to one of the three groups to receive balanced anaesthesia with bolus injections of fentanyl (group F), sufentanil (group S) or alfentanil (group A). In the recovery room all patients received the same analgesic regimen, comprising TCIA.

Pharmacokinetics of the enantiomers of mepivacaine after intravenous administration of the racemate in volunteers.

The pharmacokinetics of R(-)-mepivacaine and S(+)-mepivacaine were investigated in 10 healthy volunteers. The volunteers received racemic mepivacaine, hydrochloride (dose 60 mg) via a 10-min intravenous infusion. Blood samples were collected at gradually increasing intervals until 8 h after the start of the infusion.

Epidural vs. intravenous infusion of alfentanil in the management of postoperative pain following laparotomies.

Background: This study was designed to compare the efficacy of epidural vs. intravenous administration of alfentanil for treatment of postoperative pain.

Methods: Twenty patients were randomly allocated to one of the two study groups to receive either an epidural bolus dose (0.

High-performance liquid chromatographic assay of mepivacaine enantiomers in human plasma in the nanogram per milliliter range.

A method enabling quantification of R-(-)- and S-(+)-mepivacaine in human plasma in the low nanogram per milliliter range is described. The procedure involves extraction from plasma with diethyl ether, centrifugation, back-extraction into an acidified aqueous solution, washing with a mixture of pentane and isoamylalcohol, alkalinisation, followed by extraction with a mixture of n-pentane and isoamylalcohol. After evaporation of the organic phase, the residue is redissolved in the mobile phase used for the HPLC analysis, which consists of a 6.

Pharmacodynamic interaction between propofol and alfentanil when given for induction of anesthesia.

Background: Propofol and alfentanil often are combined during induction of anesthesia. However, the interaction between these agents during induction has not been studied in detail. The influence of alfentanil on the propofol concentration-effect relationships was studied for loss of eyelash reflex, loss of consciousness, and hemodynamic function in 20 unpremedicated ASA physical status 1 patients aged 20-55 yr.

Performance of computer-controlled infusion of propofol: an evaluation of five pharmacokinetic parameter sets.

Computer-controlled infusion of propofol is used with increasing frequency for the induction and maintenance of anesthesia. The performance of computer-controlled infusion devices is highly dependent on how well the implemented pharmacokinetic parameter set matches the pharmacokinetics of the patient. This study examined the performance of a computer-controlled infusion device when provided with five different pharmacokinetic parameter sets of propofol in female patients.

Computer-controlled infusion of alfentanil versus patient-controlled administration of morphine for postoperative analgesia: a double-blind randomized trial.

This study compared the efficacy of computer-controlled infusion of alfentanil (CCiA) with patient-controlled administration of morphine (PCAM) for postoperative analgesia. Twenty patients were randomly allocated to one of the two study groups to receive either an intravenous CCiA or PCAM regimen. Pain scores measured on a visual analog scale (VAS) and the number of valid demands were used as variables to evaluate the efficacy of the postoperative analgesic therapy.

The pharmacodynamic interaction of propofol and alfentanil during lower abdominal surgery in women.

Background: Propofol and alfentanil are frequently combined to provide general anesthesia. The purpose of this study was to characterize the pharmacodynamic interaction between propofol and alfentanil for several clinically relevant end points.

Methods: Twenty-one women, aged 20-55 yr, scheduled for lower abdominal surgery, were randomly assigned in a double-blind manner to one of three groups to receive a computer-controlled infusion of propofol with target concentrations of 2, 4, or 6 micrograms/ml.

The effect of epidural administration of alfentanil on intra-operative intravenous alfentanil requirements during nitrous oxide-oxygen-alfentanil anaesthesia for lower abdominal surgery.

The effects of epidural administration of alfentanil on the intravenous alfentanil dose requirements and the plasma concentrations required to suppress responses to surgical stimulation during nitrous oxide-oxygen-alfentanil anaesthesia in 20 patients undergoing lower abdominal surgery were studied. Before induction of anaesthesia, patients in one group (E) received an epidural injection of 1 mg alfentanil, followed by an epidural infusion of alfentanil 0.2 mg.

Plasma concentrations of alfentanil following epidural administration.

The plasma concentration-time profile of alfentanil following epidural administration was determined in eight patients undergoing lower abdominal surgery under nitrous oxide (66%)-oxygen (33%)-halothane (0.3%) anaesthesia, supplemented with intravenous sufentanil. Alfentanil (1 mg) was administered epidurally before induction of general anaesthesia.

Pharmacokinetics of alfentanil after epidural administration. Investigation of systemic absorption kinetics with a stable isotope method.

Background: The effects of epidurally administered alfentanil may be due in part to its uptake into the systemic circulation. Therefore we examined the systemic absorption kinetics after epidural injection of alfentanil.

Methods: Pharmacokinetics were determined using a stable isotope method in ten patients, undergoing lower abdominal surgery under general anesthesia.

Influence of Crohn's disease on the pharmacokinetics and pharmacodynamics of alfentanil.

We have compared the dose requirements, pharmacokinetics and pharmacodynamics of alfentanil in 12 patients with Crohn's disease and 10 control patients undergoing abdominal surgery. Plasma concentrations of alpha 1-acid glycoprotein (AAG) and alfentanil protein binding were also measured. Anaesthesia was induced with alfentanil 100 micrograms kg-1 and thiopentone, and maintained with nitrous oxide in oxygen and alfentanil 25-200 micrograms kg-1 h-1.

Computer-controlled infusion of alfentanil for postoperative analgesia. A pharmacokinetic and pharmacodynamic evaluation.

Background: Although computer-controlled infusion (CCI) of alfentanil has been shown to be effective intraoperatively, this technique has not been validated for postoperative use. Therefore, the authors examined the efficacy of this technique in providing postoperative pain relief. The study comprised both a validation of published pharmacokinetic data sets and the definition of the minimum effective analgesic concentrations after major orthopedic surgery.

Pharmacodynamics of alfentanil as a supplement to propofol or nitrous oxide for lower abdominal surgery in female patients.

Background: Although propofol and alfentanil are given in combination in clinical practice, the pharmacodynamic interaction between these drugs has not been described.

Methods: The pharmacodynamics of alfentanil when given as a supplement to propofol were studied in 10 ASA physical status 1 female patients (group P) undergoing lower abdominal surgery and compared to the pharmacodynamics of alfentanil when given as a supplement to nitrous oxide (group N, n = 10). Anesthesia was induced by either computer-controlled infusion of propofol and alfentanil at target concentrations of 3 micrograms/ml and 100 ng/ml (group P) or computer-controlled infusion of 400 ng/ml alfentanil as a supplement to nitrous oxide and oxygen (ratio 2:1; group N).

Pharmacodynamics of propofol in female patients.

Although the clinical properties of propofol have been studied extensively, the pharmacodynamics have not yet been described fully. We studied the propofol concentration-effect relationships for loss of eyelash reflex, loss of consciousness, and hemodynamic changes in 18 female patients, ASA physical status 1, aged 20-49 yr. Propofol was given by computer-controlled infusion.

Pharmacokinetics of alfentanil before and after cardiopulmonary bypass in pigs: Part II.

The pharmacokinetics of alfentanil before and after cardiopulmonary bypass (CPB) were investigated in six pigs undergoing mitral valve replacement. Before bypass, alfentanil, 100 micrograms/kg, was infused in 10 minutes and after bypass, alfentanil, 40 micrograms/kg, was infused in 10 minutes. Low inspiratory concentrations of halothane were given concomitantly.

Pharmacokinetics of alfentanil before and after cardiopulmonary bypass in pediatric patients undergoing cardiac surgery: Part I.

Changes induced by cardiopulmonary bypass (CPB) may markedly affect the pharmacokinetics of drugs. Therefore, the pharmacokinetics of alfentanil before and after CPB were compared in infants and children undergoing cardiac surgery, who had been anesthetized with nitrous oxide in oxygen and low inspiratory concentrations of halothane. Six infants and six children were investigated.