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Biomedical subjects

C R Dundas

Publications and source records attributed to C R Dundas.

7 recordsLinked to original sources
PubMed1990

The value of flumazenil in the reversal of midazolam-induced sedation for upper gastrointestinal endoscopy.

Fifty patients who underwent diagnostic upper gastrointestinal endoscopy after midazolam sedation were randomized to receive (after completion of the examination) either the benzodiazepine receptor antagonist flumazenil or an identical-looking placebo. The speed of recovery from sedation was assessed by reaction time testing, measurement of critical flicker fusion frequency, and the semi-quantitative SOCA scoring system. Measurements were made up to 6 h post examination in all subjects, and at 12 and 24 h in all in-patients (n = 20). Flumazenil-treated patients were significantly more alert than those who received placebo at 10 min, 30 min, 1 h and 2 h (P less than 0.001 in all instances). Thereafter the two groups were similar. There was no evidence of recurrence of sedation in flumazenil-treated patients, nor did this drug adversely affect the period of anterograde amnesia between the administration of midazolam and flumazenil.

Adolescent↗
PubMed1990

Induction agents for day-case anaesthesia. A double-blind comparison of propofol and midazolam antagonised by flumazenil.

Early postoperative recovery was studied using sedation scoring, measurement of flicker fusion frequency and completion of Trieger test figures in 60 male patients who presented for vasectomy under general anaesthesia as day patients. Anaesthesia was induced in groups 1 and 2 (20 patients each) with mean (SD) doses of 0.16 (0.04) mg/kg or 0.16 (0.03) mg/kg midazolam respectively; group 2 received flumazenil 0.55 (0.19) mg after completion of surgery. The remaining 20 patients (group 3) received propofol 1.50 (0.24) mg/kg. Anaesthesia was maintained with isoflurane vaporized in 33% oxygen and nitrous oxide in all patients. Flumazenil tended to improve tests of recovery after midazolam anaesthesia, but early recovery after propofol anaesthesia was associated with better psychomotor test results and less impairment of mental state as judged by sedation and amnesia scoring.

Adult↗
PubMed1989

Anaesthetic agents and their effect on tissue protein synthesis in the rat.

1. Rates of protein synthesis were measured, in vivo, in lung, liver, heart and skeletal muscle of young male rats. Groups of rats were exposed for 1 h duration to one of the following anaesthetic regimens: 1.4% halothane, 2.2% halothane, 1.4% halothane in 66% nitrous oxide, intravenous pentobarbitone (20 mg/kg) and intravenous midazolam (18 mg/kg) combined with fentanyl (2 micrograms/kg). Fractional rates of protein synthesis were determined by injecting [3H]phenylalanine (150 mumol/100 g body weight). 2. Liver protein synthesis was depressed significantly by all regimens, except midazolam/fentanyl, by up to 37.7% of control values. Lung protein synthesis was significantly reduced by all the anaesthetic agents by up to 30% of control rates. 3. The effects of the anaesthetic agents on skeletal muscle and heart were small and not statistically significant. 4. There was no evidence of ventilatory depression as manifested by changes in arterial blood gas partial pressures of CO2 and O2, except in the group treated with 2.2% halothane.

Anesthetics↗
PubMed1987

Effects of H-2 antagonists on the elimination of bupivacaine.

The effects of two histamine H-2 antagonists, cimetidine and ranitidine, on the elimination of bupivacaine were studied in four male volunteers. The cimetidine-treated group demonstrated a statistically significant decrease in clearance of bupivacaine. These results indicate that concomitant administration of cimetidine and bupivacaine may increase the likelihood of toxicity of the latter agent.

Bupivacaine↗
PubMed1987

Monitoring neuromuscular blockade. The table knife transducer.

A simple and inexpensive force transducer made from a stainless steel table knife is described. Construction is straightforward and utilises strain gauges that are readily available. Amongst its attributes are lightness, ease of application, low sensitivity to postural changes and linearity over extended periods of time.

Equipment Design↗
PubMed1979

A paediatric ventilator with a fluidic control system.

A paediatric ventilator has been designed basically as a fluidic-logic controlled T-piece occluder. Inspiratory and expiratory time, inflation pressure limit, positive end-expiratory pressure (PEEP), continuous positive airway pressure (CPAP) and inspiratory flow-rate are controlled independently and intermittent mandatory ventilation (IMV) is available. Warning systems are provided for failure of the driving as, low airway pressure and inspiratory pressure limit. The breathing circuit is isolated from the control and warning systems for ease of sterilization.

Air Pressure↗