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Biomedical subjects

M Bahar

Publications and source records attributed to M Bahar.

49 records · Page 3Linked to original sources
PubMed1983

Physostigmine antagonizes morphine-induced respiratory depression in human subjects.

The effect of physostigmine on the respiratory depression induced by morphine was studied in human subjects who received morphine as part of their preanesthetic medication. After pretreatment with droperidol (2.5-5 mg, iv) to prevent nausea, the change in minute ventilation was measured in 16 patients in response to increasing concentrations of inspired CO2 (CO2-response curve) by the rebreathing method. This was repeated 30 min after morphine (0.166 mg/kg, iv) in nine subjects and in seven controls who did not receive morphine and again 5-10 min after physostigmine (13-33 micrograms/kg, iv) in all subjects. All subjects were given N-butylhyoscine hydrobromide (5 mg, iv) to antagonize any peripheral cholinergic effects of physostigmine. Morphine decreased the mean slope of the CO2-response curve from 1.78 +/- 0.18 to 1.12 +/- 0.14 1 X min-1 X mmHg-1 (P less than 0.01) and increased the alveolar PCO2 for a fixed minute ventilation (position of curve) from 45.0 +/- 1.3 to 51.9 +/- 1.5 mmHg (P less than 0.001). Physostigmine restored the mean slope after morphine to control value, i.e., 1.79 +/- 0.231 X min-1 X mmHg-1, and position to 46.2 +/- 1.2 mmHg (P less than 0.001). Physostigmine did not increase the slope or alter the position of the CO2-response curves of subjects given droperidol alone. The authors conclude that physostigmine can reverse the respiratory depressant effect of morphine and restore the sensitivity of the respiratory center of CO2, presumably by raising acetylcholine levels in the brain after these have been reduced by morphine.

Adolescent↗
PubMed1982

Effect of preanaesthetic medication on anaesthesia with ICI 35, 868.

The effect of three commonly used premedicants and a control on anaesthesia with ICI 35, 868 is described. Two randomized studies were performed--one a group study of induction characteristics at 2 mg kg-1 and the other a detailed study in patients undergoing minor gynaecological surgery with an induction dose of 1.5 mg kg-1 and maintenance with incremental doses plus 66% nitrous oxide in oxygen. Premedication had little effect on the already good induction characteristics. Only heavy opiate premedication produced reliable induction at 1.5 mg kg-1, but with an increase in side-effects. Diazepam appears to be the premedicant of choice, although the overall frequency of pain on injection has not been affected by premedication.

Adolescent↗
PubMed1982

Comparison of the effect of diisopropyl phenol (ICI 35, 868) and thiopentone on response to somatic pain.

The response to somatic pain with sub-hypnotic doses of ICI 35, 868 (diisopropyl phenol in cremophor) and thiopentone was compared using tibial pressure algesimetry. Studies were also carried out following recovery from larger doses of both drugs. The patients underwent gynaecological procedures using only one of the two i.v. agents and nitrous oxide in oxygen. The studies confirmed the known antanalgesic action of thiopentone and demonstrated that diisopropyl phenol has an analgesic action which is an attractive feature in an i.v. anaesthetic agent.

Anesthesia, Intravenous↗
PubMed1982

Recovery from intravenous anaesthesia. Comparison of disoprofol with thiopentone and methohexitone.

Using the endpoints of spontaneous opening of eyes, giving date of birth, sitting up unaided and normal pegboard time, recovery from 2 and 3 mg/kg disoprofol was compared with that from 4 and 6 mg/kg thiopentone and 1.5 mg/kg methohexitone in groups each of 10 unpremedicated patients. The study method differentiated between recovery from the two doses of disoprofol and thiopentone at the first two endpoints only. A between-drug comparison showed early recovery was slightly faster with thiopentone than with equivalent doses of the new drug while no differences were detected between the recovery from equivalent doses of methohexitone and thiopentone. The differences found in this study are felt to be of no clinical significance and recovery from anaesthesia with disoprofol would not be expected to be any slower than that from equivalent doses of thiopentone.

Adult↗
PubMed1981

Use of di-isopropyl phenol as main agent for short procedures.

The use of di-isopropyl phenol (Diprivan) for induction of anaesthesia was assessed in doses ranging from 1 to 3 mg kg-1. With less than 1.75mg kg-1 not all patients were anaesthetized; 2.0 mg kg-1 appeared to be a satisfactory induction dose. Involuntary muscle movement, cough and hiccup at induction were rare with any dose studied. However, the frequency of hypotension and respiratory depression were related to the dose given. Pain on injection was uncommon when the drug was given into an antecubital vein, but occurred in 39% of patients when injected to the back of the hand or wrist. Recovery was rapid, and characterized by lack of emetic sequelae. Di-isopropyl phenol 1.5 - 2.0 mg kg-1 given rapidly during reactive hyperaemia can produce anaesthesia in one arm-brain circulation time. A reaction involving flush, hypotension, cough, laryngospasm and bronchospasm occurred in one patient receiving 2.5 mg kg-1 given over 20 s.

Adult↗
PubMed1980

Physostigmine antagonizes morphine-induced respiratory depression but not analgesia in dogs and rabbits.

The ability of physostigmine to antagonize the respiratory depressant effect of morphine was studied in conscious rabbits and ketamine-anaesthetized dogs pretreated with atropine methyl nitrate. Morphine 4 mg kg-1 increased PaCO2 in the rabbit from 3.43 +/- 0.16 to 4.95 +/- 0.28 kPa, decreased arterial pH from 7.45 +/- 0.01 to 7.31 +/- 0.01 and decreased respiratory frequency by 36%. Physostigmine 0.1 mg kg-1 reduced PaCO2 to control values within 10 min and significantly increased arterial pH and respiratory frequency. There was no antagonism of the analgesic effect of morphine. Neostigmine 0.1 mg kg-1 did not reverse the respiratory depressant effect of morphine. In dogs anaesthetized with ketamine, morphine 15 mg kg-1 caused loss of consciousness and marked analgesia, decreased the respiratory frequency by 47%, and increased PaCO2 by 47%. Physostigmine 0.1 mg kg-1 antagonized the effect of morphine on respiration and restored consciousness in the dogs, but did not impair analgesia. It is concluded that physostigmine reverses morphine-induced respiratory depression by prolonging the effect of acetylcholine released from brain-stem neurones. The possibility should be considered of replacing opiate antagonists by physostigmine to reverse postoperative respiratory depression and drowsiness induced by opiates.

Analgesics↗
PubMedDate not supplied

Effects of anesthesia in elective surgery on the memory of the elderly.

The effects of anesthesia in elective operations on the cognitive functioning of the elderly, was examined in 88 patients aged 60-90 years. These patients were assessed pre-operatively and at a week and three months post-operatively. Forty patients (44.5%) received general anesthesia and 48 (54.5%) received regional anesthesia. The results show no significant difference between the two anesthetic methods. Differences were noted in remote memory index between the three examination time periods. (In contrast to a later work, it was found that patients whose cognitive state had been low deteriorated more than others). The only differences found between younger and older patients were in remote, recent and immediate memory. One of the major conclusions was that the effects of the methods of anesthesia, general and regional, are no different in young and elderly patients.

Journal Article↗