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P Balendran

Publications and source records attributed to P Balendran.

4 recordsLinked to original sources
PubMed1993

Pharmacodynamic behaviour of rocuronium in the elderly.

This study compared the potency and time course of action of rocuronium (ORG 9426) in elderly and young patients during nitrous oxide-opioid anaesthesia. One hundred ASA physical status I-II patients (60, aged 65-80 yr, and 40, aged 20-45 yr) were studied by measuring the force of contraction of the adductor pollicis in response to train-of-four stimulation of the ulnar nerve. After induction of anaesthesia with thiopentone and maintenance with N2O/O2 and fentanyl, rocuronium 120, 160, 200, or 240 micrograms.kg-1 was administered to determine dose-response curves. When maximum block had been obtained, further rocuronium to a total of 300 micrograms.kg-1 was given. Additional doses of 100 micrograms.kg-1 were administered when the first twitch height (T1) had recovered to 25% control. At the end of surgery neuromuscular blockade was allowed, whenever possible, to recover spontaneously until T1 was 90% of control before administration of neostigmine. There was no difference in the potency of rocuronium in the elderly and the younger patients. The ED50 was 196 +/- 8 (SEE for the mean) in elderly, vs 215 +/- 17 micrograms.kg-1 in young patients (NS). When individual cumulative dose-response curves were constructed, the ED50 was 203 +/- 7 (SEM) and 201 +/- 10 micrograms.kg-1 in the elderly and the young respectively (NS). However, the onset of maximum neuromuscular block was slower in the elderly 3.7 +/- 1.1 (SD) vs 3.1 +/- 0.9 min, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Vecuronium is more potent in Montreal than in Paris.

This study was undertaken to compare the potency of vecuronium in patients anaesthetized in Montreal or Paris. Anaesthesia was induced with thiopentone and maintained with N2O, and intermittent boluses of thiopentone and fentanyl in 18 patients in Paris and 19 in Montreal. Neuromuscular blockade was measured using train-of-four stimulation of the ulnar nerve. The force of contraction of the adductor pollicis muscle was measured. Single doses of vecuronium, 20, 30, or 40 micrograms.kg-1 were given by random allocation. Dose response curves were constructed by obtaining the linear regression of the logit of the first response (T1) neuromuscular blockade versus log dose. The patients in Paris required 27% more vecuronium (95% confidence limits 5-53%; P = 0.01) for the same intensity of blockade. In Montreal, the ED50 and ED90 (+/- SEE for the mean) values were 26.0 +/- 1.4 and 44.2 +/- 2.5 micrograms.kg-1 compared with 33.0 +/- 3.3 and 71.9 +/- 7.2 micrograms.kg-1 in Paris respectively. The patients were comparable with respect to age, sex, height and weight. These results confirm, for vecuronium, the transatlantic difference in potency of neuromuscular blocking drugs which was previously observed with d-tubocurarine between London and New York.

Adult↗
PubMed1991

Nitrous oxide potentiates vecuronium neuromuscular blockade in humans.

This study was designed to measure the potency of vecuronium with and without nitrous oxide. Anaesthesia was induced with thiopentone and fentanyl in 56 adult patients. The subjects were randomly assigned to receive nitrous oxide, 70%, or intermittent boluses of thiopentone and fentanyl for maintenance of anaesthesia. Train-of-four stimulation was applied to the ulnar nerve every 20 sec, and the force of contraction of the adductor pollicis muscle was measured. Vecuronium, 20, 30 or 40 micrograms.kg-1 was given by random allocation five minutes after induction of anaesthesia. Maximum depression of the first response (T1) in the train-of-four was measured, and dose-response curves were constructed. In the absence of nitrous oxide, the ED50 and ED95 were mean +/- standard error of the mean (SEM), 29.2 +/- 1.8 and 59.3 +/- 3.6 micrograms.kg-1, respectively. In the group receiving nitrous oxide, these values were 25.3 +/- 1.2 and 42.3 +/- 2.0 micrograms.kg-1 respectively. By analysis of covariance, the dose-response curves were shown to be shifted with respect to one another (P less than 0.05). Administration of nitrous oxide was associated with a 19.5% increase in potency (95% confidence limits: 1.7 to 40.4%). It is concluded that nitrous oxide has a slight potentiating effect on neuromuscular blockade, and that this effect occurs within five to ten minutes after the beginning of its administration.

Adult↗