Articles: anesthetics.
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Comparative Study
Infusions of propofol to supplement nitrous oxide-oxygen for the maintenance of anaesthesia. A comparison with halothane.
The peri-operative and postoperative effects of propofol given by infusion were compared with halothane as a supplement to nitrous oxide-oxygen anaesthesia for body surface surgery in patients who breathed spontaneously. Anaesthesia was induced after opioid premedication, with either propofol 2.5 mg/kg or thiopentone 4-5 mg/kg which were followed respectively by an infusion of propofol 12 mg/kg/hour for 10 minutes and at a variable rate thereafter, or by halothane at a mean inspired concentration of 1.2%. ⋯ The cardiovascular effects during induction and maintenance of anaesthesia were similar in the two groups. The overall incidence of side effects was low but immediate recovery was significantly faster in patients who received propofol.
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Randomized Controlled Trial Comparative Study Clinical Trial
Recovery times and side effects after propofol infusion and after isoflurane during ear surgery with additional infiltration anaesthesia.
Two anaesthetic procedures that did not include nitrous oxide were compared in a randomised study of 50 patients for tympanoplasty and tympanoscopy: propofol given for induction and maintenance, and thiopentone-isoflurane given for induction and maintenance, respectively. Induction in the first group was with a bolus injection of propofol and the same agent was given for the duration of anaesthesia by continuous intravenous administration. Thiopentone was given until loss of the eyelash reflex and anaesthesia maintained with isoflurane 0.4-2.0%. ⋯ The two patient groups were analysed for age, sex and weight as well as for side effects during the induction, maintenance and recovery periods, such as coughing, vomiting, venous pain, spontaneous movements, singultus, headaches, dysrhythmias and psychic disorders possibly due to anaesthesia. Side effects were moderate in both groups. Recovery time was statistically significantly shorter in the propofol group and the patients in this group appeared to be much more aware after recovery than those in the thiopentone-isoflurane group.
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Twenty patients, ASA grades 1 and 2, aged 18-65 years were admitted to an open study to investigate the ease of tracheal intubation after induction of anaesthesia with propofol without the use of muscle relaxants after the chance observation that propofol 2.5 mg/kg allowed easy laryngoscopy and tracheal intubation. Satisfactory intubation conditions were achieved in 19 patients.
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The pharmacokinetics of a constant rate infusion of propofol were studied in 11 patients who received total intravenous anaesthesia for ENT surgery. Alfentanil was administered as an exponentially decreasing infusion using a computer-assisted infusion device with a constant target plasma alfentanil concentration of 300 ng/ml. Propofol was infused at a constant rate of 6 mg/kg/hours. ⋯ Only three data sets were significantly underestimated after the infusion was stopped (mean bias 11.9% (SD 25.5]. The elimination half-life of alfentanil was approximately 75 minutes (SD 21). We conclude that alfentanil does not interfere with the pharmacokinetic profile of propofol but that propofol induces higher plasma alfentanil concentrations than expected.
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The relationship between the age and the spread of analgesia from different epidural anesthetic doses was examined by studying analgesic dose responses in cervical epidural analgesia. Two different anesthetic doses (5 ml or 10 ml) of 2% mepivacaine were injected into the cervical epidural space at a constant pressure (80 mmHg) using an intravenous apparatus, and the spread of analgesia to pinprick was assessed. The significant correlation was found between the patient's age and the number of spinal segments blocked (5 ml : r = 0.8498, P < 0.01, 10 ml : r = 0.5988, P < 0.01). ⋯ The analgesic dose-response relation in patients over 60 years of age differed from that in patients under 39 years of age and doubling the epidural dose did not double the number of spinal segments blocked. Progressively more extensive analgesia was obtained from a given dose of local anesthetic with advancing age. It was difficult to limit the extent of analgesia by injecting a smaller dose of local anaesthetic in the elderly.