ABSTRACT
The authors evaluated the efficacy and incidence of side effects from blockade of the femoral nerve with 0.5% bupivacaine in 14 children with fracture of the middle third of the femoral shaft. In nine of these children, a pharmacokinetic analysis was also performed. The onset of analgesia occurred in 8.0 +/- 3.5 minutes after blockade of the femoral nerve. One block failed, resulting in iv narcotics being administered to alleviate the pain. In the remaining 13 children, pain decreased to nonexistent in 11 of the children and only mild pain with movement in the remaining two children. The level of analgesia did not change when the children underwent radiographic examination (60 +/- 18 min after the femoral nerve block) and application of traction (124 +/- 19 min after femoral nerve block). The maximum bupivacaine plasma concentration was 0.89 +/- 0.37 microgram/ml, obtained 24.4 +/- 12.6 min after the end of the injection. The femoral nerve blockade with bupivacaine provides prompt, effective, and prolonged analgesia in children suffering from fractures of the femoral shaft, allowing transport, radiographic examination, and application of traction in optimal conditions. Although the sample size was small, the side effects appeared to be rare.
Subject(s)
Bupivacaine , Femoral Fractures , Femoral Nerve , Nerve Block , Bupivacaine/pharmacokinetics , Child , Child, Preschool , HumansABSTRACT
Analgesia can be obtained during ophthalmic surgery by regional anesthesia using local anesthetic agents. As in other indications, neurological complications may occur, especially because the site of injection is close to the central nervous system. In order to evaluate the risk of retrobulbar and facial block obtained after 40 mg lidocaine and 20 mg bupivacaine injection, pharmacokinetics of both drugs was evaluated in plasma obtained from 11 patients. In addition, 3 cerebrospinal fluid samples were analyzed. Maximal plasma concentration was 0.73 +/- 0.33 micrograms.ml-1 for lidocaine and 0.19 +/- 0.06 micrograms.ml-1 for bupivacaine, obtained 24.7 +/- 23.0 min and 12.0 +/- 3.7 min after the end of injection, respectively. CSF/plasma ratio was in the range 0.05-0.26 for lidocaine and 0.56-1.33 for bupivacaine. In all patients, regional anesthesia was sufficient to perform surgery without any other analgesic drug. No sign of cardiovascular or respiratory toxicity was observed during the study.
Subject(s)
Anesthesia, Local , Bupivacaine/pharmacokinetics , Lidocaine/pharmacokinetics , Adult , Aged , Aged, 80 and over , Bupivacaine/blood , Bupivacaine/cerebrospinal fluid , Face , Female , Humans , Injections , Lidocaine/blood , Lidocaine/cerebrospinal fluid , Male , Medulla Oblongata , Middle AgedABSTRACT
1. The use of continuous infusion anaesthesia has only been of interest since the development of short-acting, less cumulative and less toxic drugs. 2. This study aimed to compare pharmacokinetics and haemodynamic effects during and after long time methohexitone constant rate infusion. Sixteen patients were given either 60 or 90 micrograms kg-1 min-1 methohexitone during 14 h. Blood samples were taken hourly during this time and 12 h following the end of infusion. 3. Infusion period was analysed by a single exponential model; post-infusion time showed a three compartment model, the intermediate phase parameters corresponding to those of the infusion period. 4. Methohexitone was haemodynamically well tolerated; prolonged infusion decreases oxygen consumption, mainly by a decrease in oxygen demand. 5. Many patients remained unconscious for unacceptably long periods of time after post-operative sedation by methohexitone.
Subject(s)
Hemodynamics/drug effects , Methohexital/pharmacokinetics , Humans , Infusions, Intra-Arterial , Methohexital/administration & dosage , Methohexital/pharmacology , Oxygen Consumption/drug effects , Time FactorsABSTRACT
A gas chromatographic method for routine quantitation of methohexital in plasma samples is reported. One-step extraction in organic phase, the use of a fused silica capillary column, and nitrogen-selective detection permit simple, precise, and sensitive determination of methohexital in plasma. A linear relationship is described between peak height ratio and methohexital concentrations ranging from 0.125 to 50.0 micrograms/ml (r = 0.998). The sensitivity limit of the assay was 6 ng/ml in plasma. No interfering peak was observed with numerous other drugs. The procedure was successfully applied to the determination of pharmacokinetic parameters of methohexital after IV administration or continuous infusion in a child and an adult.
Subject(s)
Methohexital/blood , Chemical Phenomena , Chemistry , Chromatography, Gas , Humans , Methohexital/metabolism , Methohexital/pharmacokineticsABSTRACT
A method for estimating bupivacaine concentration in human plasma by capillary gas-chromatography using solid injection and nitrogen-specific detection is described. Etidocaine, another anilidetype local anesthetic was used as internal standard and added to the sample before single-step extraction with diethylether. This method demonstrates high sensitivity (6 ng/ml plasma) and combines selectivity, rapidity, and simplicity. Results of this procedure correlate well with those obtained by an HPLC method.
