Search PubMed⌕ Search

Biomedical subjects

R S Clarke

Publications and source records attributed to R S Clarke.

At least 73 records · Page 4Linked to original sources
PubMed1982

Effects of neostigmine and pyridostigmine on serum cholinesterase activity.

Serum cholinesterase activities were measured from 270 minutes in patients following administration of neostigmine or pyridostigmine for the reversal of pancuronium block in groups of seven patients each. The enzyme activities were significantly depressed by neostigmine for four hours and by pyridostigmine throughout the whole period of study. Whereas the immediate effects of neostigmine were more intense, the effects of pyridostigmine beyond the first 30 minutes were more profound. The clinical relevance of these findings is discussed.

Adult↗
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↗
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↗
PubMed1981

Comparison of atropine and glycopyrrolate in a mixture with pyridostigmine for the antagonism of neuromuscular block.

Neuromuscular block was antagonized using pyridostigmine 250 micrograms kg-1 in two groups of 50 patients; one group received atropine 20 micrograms kg-1 and the other glycopyrrolate 10 micrograms kg-1 with the anticholinesterase drug. Atropine was associated with a greater initial tachycardia than was glycopyrrolate. The subsequent bradycardia was also greater in this group, although the decreases in heart rate were smaller than those generally observed following mixtures of atropine and neostigmine. Arrhythmias were transient and required no treatment in either group. Better control of secretions was achieved with glycopyrrolate.

Adult↗
PubMed1981

Effect of a new analgesic, MR 1268, on circulatory and respiratory indices in volunteers.

MR 1268, a benzmorphan derivative with marked morphine-like properties and weaker antagonist properties was administered to six healthy male volunteers who each received MR 1268 2.5,5,10 and 20 mg i.v. in random order. There were no significant changes in the cardiovascular indices measured. However, significant and dose-related decreases in expired minute volume were observed. With 20 mg, consistent increases in Paco2 coincided with maximum decrease in ventilation, indicating some degree of alveolar hypoventilation. Drowsiness was dose-related but of short duration and only significant with 20 mg. Pupillary size and reaction remained unaffected.

Adult↗
PubMed1981

The relationship between reported atopy or allergy and immunoglobulins: a preliminary study.

The serum of 50 surgical patients with a history of asthma, hay fever or allergy has been analysed for IgE levels and compared with a control group without such a history. The values in the 'normal' group largely fell within the accepted range (below 200 iu./ml). Those in the 'hypersensitive' group had a wide range extending to over 1000 iu./ml but many of those with low values in this group had contact dermatitis and similar minor allergies. However, analysis of cases studied shows that any patient with a history of atopy or allergy is at risk from Cremophor-containing intravenous anaesthetics.

Adult↗
PubMed1981

Minaxolone: an evaluation with and without premedication.

Minaxolone, a water-soluble steroid intravenous anaesthetic, has been used in clinical trials for induction and maintenance in patients presenting for minor operations. A standard induction dose of 0.5 mg/kg was given. There was a low incidence of pain on injection and venous sequelae. Excitatory effects occurred commonly at induction but these were reduced by opiate premedication. The frequency of uneventful induction was significantly greater when the 5 mg/ml solution of minaxolone was given at a rate of 6 ml/minute than at a rate of 24 ml/minute. Minaxolone has been withdrawn from clinical trials following equivocal toxicological findings in rats which require further investigation.

Adult↗
PubMed1981

Adverse effects of intravenously administered drugs used in anaesthetic practice.

Adverse effects of intravenous anaesthetic drugs may be divided into local and general effects. The former include venous sequelae ranging from soreness on palpation on the day after the injection to thrombosis of the whole venous system of the arm. Frequency of venous sequelae for water-soluble anaesthetics 5 to 10%; drugs sparingly soluble in water are similar in this regard when solubilised in 'Cremophor EL'. Diazepam or etomidate dissolved in propylene glycol can produce venous reactions in about 25% of patients on the 3rd day and more by the 15th day if given directly into the vein, and are really only acceptable when injected in an infusion. The general adverse effects of anaesthetic agents include excitatory effects, as well as those on the cardiovascular and respiratory systems which are almost unavoidable. Excitatory effects are diminished by suitable premedication, and the cardiovascular and respiratory effects can be minimised by low dosage and slow administration. Cardiovascular effects of the muscle relaxants are also unavoidable with the drugs presently available, but further research should provide drugs with greater selectivity. More troublesome are the hypersensitivity reactions which occur with both the induction agents and the neuromuscular blocking drugs. These range in frequency from about 1 in 30,000 with the barbiturates to about 1 in 1000 with the 'Cremophor'-containing solutions of propanidid and alphaxalone/alphadolone. However, it appears that the barbiturate reactions are more severe and prolonged. The frequency of hypersensitivity reactions following muscle relaxants is difficult to assess because marked flushing is very common following tubocurarine and bronchospasm can frequently be due to passage of an endotracheal tube. In spite of the alarm created by these reactions, provided the patient is treated in the standard manner, the mortality should be low.

Anesthesia, Intravenous↗
PubMed1981

Reversal of neuromuscular blockade: dose determination studies with atropine and glycopyrrolate given before or in a mixture with neostigmine.

Glycopyrrolate and atropine were studied in doses of 5, 10, or 15 microgram/kg and 10, 20, or 30 microgram/kg, respectively, given intravenously either before or in a mixture with neostigmine, 50 microgram/kg, at the time of reversal of neuromuscular block. When given first, both anticholinergic drugs produced a dose-related increase in heart rate; following the administration of neostigmine the heart rates decreased. When administered in a mixture with neostigmine, the 20- and 30-microgram/kg doses, but not the 10-microgram/kg dose of atropine were associated with an initial increase in heart rate. This was, however, absent with all the doses of glycopyrrolate. The 5-microgram/kg dose of glycopyrrolate and 10-microgram/kg dose of atropine given either before or in a mixture with neostigmine were associated with unacceptable decreases in heart rate and needed further anticholinergic drug administration. The 10-microgram/kg dose of glycopyrrolate, when administered in a mixture with neostigmine, was associated with the most stable heart rates. Increasing the dose to 15 microgram/kg was not associated with undue tachycardia and is not hazardous. Atropine, 20 microgram/kg, necessitated a further administration of atropine in nearly a third of patients in this group due to bradycardia (heart rate of 50 beats/min or less) and would be considered inadequate. Increasing the dose to 30 microgram/kg prevented bradycardia but was accompanied by significant initial tachycardia and a higher incidence of dysrhythmias when administered before neostigmine. The frequency of dysrhythmias was otherwise similar. It is recommended that anticholinergic drugs be administered in a mixture with neostigmine. Glycopyrrolate, administered in this way in a dose of 10 microgram/kg, is associated with stable heart rates.

Atropine↗
PubMed1980

Comparison of the subjective effects and plasma concentrations following oral and i.m. administration of flunitrazepam in volunteers.

Flunitrazepam 0.5, 1.0 or 2.0 mg was given by the oral or i.m. routes to groups of volunteers and its effects compared. Plasma concentrations of the drug were estimated by gas-liquid chromatography, in a smaller number of the subjects. The most striking effect was sedation which increased with the dose, 2 mg producing deep sleep although the subjects could still be aroused. The effects of i.m. administration were apparent earlier and sometimes lasted longer than those following oral administration. Dizziness was less marked than sedation, but increased with the dose. There was pain on i.m. injection of flunitrazepam significantly more often than with isotonic saline. Plasma concentrations varied with dose and route and corresponded qualitatively with the subjective effects. The drug was still present in measurable quantities after 24 h even with the smallest dose.

Administration, Oral↗
PubMed1980

Comparison of the subjective effects and plasma concentrations following oral and i.m. administration of flunitrazepam in patients.

The use of flunitrazepam 1 and 1.5 mg was compared as a premedicant with diazepam 10 mg and lorazepam 2.5 mg. Plasma flunitrazepam concentration were measured after oral and i.m. administration. Flunitrazepam and diazepam had a similar onset time and duration of action, both being more rapid in onset and shorter in duration than lorazepam I.m. flunitrazepam had a slightly greater sedative effect than oral flunitrazepam and plasma concentrations correlated well with the onset of the sedative effect by either route of administration. The i.m. injection of flunitrazepam was not as painful as that of diazepam, but slightly more painful than lorzepam. A second peak occurred at about 5 h and flunitrazepam was still detectable at 48 h. The plasma half-life was 3-4 h.

Administration, Oral↗