PubMed HealthSearch

Biomedical subjects

A W Crossley

Publications and source records attributed to A W Crossley.

16 recordsLinked to original sources

The characteristics of the inhibition of serum cholinesterase by metoclopramide.

The inhibition of serum cholinesterase by metoclopramide has been previously characterised in vitro at high dilution of the enzyme. We examined the effect of varying enzyme dilution over a range of 1000 fold dilution, and assay temperature at 25 degrees C and 37 degrees C on the fractional inhibition of enzyme activity by metoclopramide. Neither enzyme concentration nor reaction temperature affected this fractional inhibition. Concentrations of metoclopramide producing 50% inhibition of enzyme activity were in the range 1.0-1.9 x 10(-6) M. Lineweaver-Burk analysis of the enzyme reaction suggests that the pattern of this inhibition is competitive.

Cholinesterase Inhibitors

The effect of different end-tidal volatile agent and carbon dioxide concentrations upon the incidence of postoperative shivering.

Sixty patients (47 female) undergoing surgical excision of three or more wisdom teeth were randomly allocated into three groups with differing end-tidal carbon dioxide and volatile agent concentrations during maintenance of anaesthesia. The anaesthetic techniques employed were identical in all other respects. All patients were observed for 10 min after arrival in the recovery area to assess the presence and severity of shivering, axillary temperature and oxygen saturation. There were no significant differences in axillary temperatures between groups or between shivering and non-shivering patients, although there was a significant difference (p = 0.001) in duration of anaesthesia between shivering and non-shivering patients. There was no significant difference between groups with respect to the incidence of shivering (p = 0.96).

Adult

An assessment of morphine requirement after wisdom tooth extraction under general anaesthesia.

The use of morphine delivered by a patient-controlled analgesia system was studied in 20 patients who had undergone surgical extraction of three or four wisdom teeth as inpatients. Whilst 64.3% of the patient requests were made in the first 8 postoperative hours, use of the system continued throughout the night in the majority of patients. The implications for analgesic regimens in day-case surgery are discussed.

Ambulatory Surgical Procedures

Anticholinergic premedication influences the incidence of postoperative shivering.

We studied 225 healthy adult patients undergoing ENT, dental or orthopaedic surgery; they were allocated randomly to receive one of three different premedications, all given i.m. 1 h before operation. Group 1 received morphine 0.15 mg kg-1 and metoclopramide 10 mg; group 2 received morphine 0.15 mg kg-1 and glycopyrronium 5 micrograms kg-1; group 3 received morphine 0.15 mg kg-1 and hyoscine 5 micrograms kg-1. Patients who were premedicated with an anticholinergic had a significantly greater incidence and severity of postoperative shivering than those in the metoclopramide group. There was no difference in core temperature between patients who shivered and those who did not, either before or during the shivering episode. Shivering did not cause any clinically significant changes in heart rate, arterial pressure, ventilatory frequency or oxygen saturation. As this effect occurred with both glycopyrronium and hyoscine, it suggests that the mechanism by which postoperative shivering is influenced is peripheral to the central nervous system.

Adolescent

The intensity of postoperative shivering is unrelated to axillary temperature.

The relationship between axillary temperature and postoperative shivering was examined in 302 patients who entered one recovery room in the Derbyshire Royal Infirmary over a one-month period. No relationship was found between temperature and the occurrence of shivering, or between conscious level and the occurrence of shivering.

Anesthesia Recovery Period

A comparison of thiopentone and propofol with respect to the incidence of postoperative shivering.

One hundred patients (69 female) undergoing surgical excision of three or more wisdom teeth were randomly allocated to receive either thiopentone or propofol for induction of anaesthesia. Other than the induction agent, the anaesthetic regimen was standardised for all cases. All patients were observed for 15 min after entry into the recovery area to assess the presence and intensity of shivering. Twenty-five patients in the thiopentone group (n = 50) and 11 patients in the propofol group shivered postoperatively (p < 0.005). There was no statistically significant difference in axillary temperature between shivering and non-shivering patients. The use of propofol as an induction agent is associated with a lower incidence of postoperative shivering than thiopentone.

Adult

Double-blind comparison between doxapram and pethidine in the treatment of postanaesthetic shivering.

Sixty patients who shivered after routine surgery under general anaesthesia were allocated randomly to receive normal saline (n = 20), doxapram 1.5 mg kg-1 (n = 20) or pethidine 0.33 mg kg-1 (n = 20). Both doxapram and pethidine were effective in treating postoperative shivering 2-3 min after i.v. administration. In the group who received normal saline, 15 patients were still shivering 10 min after treatment, whilst in the doxapram group only three patients were shivering at that time. In the pethidine group, all patients had stopped shivering by 7 min after treatment. We conclude that both doxapram and pethidine were effective in the treatment of postoperative shivering.

Adolescent

Six months of shivering in a district general hospital.

Of 2595 patients admitted to a recovery room in Derbyshire Royal Infirmary over a 6-month period, 164 (6.3%) shivered postoperatively. Data regarding the anaesthetic techniques to which these patients had been subjected were gathered from the Derby Anaesthetic Audit System. Subsequent analysis demonstrated the importance of a number of factors that led to shivering, including male gender, anaesthetic techniques involving spontaneous ventilation, and anticholinergic premedication. The administration of pethidine, alfentanil or morphine intra-operatively reduced the incidence of shivering postoperatively.

Adolescent

Radiographic study of intercostal nerve blockade in healthy volunteers.

The spread of solutions injected to the intercostal space was studied in 10 healthy volunteers. Up to 20 ml of a 50:50 mixture of local anaesthetic solution and a radiopaque dye was injected through a modified extradural catheter placed in an intercostal space at the posterior angle of the rib. Radiographic films demonstrated spread by an extrapleural route into adjacent intercostal spaces and this was confirmed by the occurrence of analgesia in the corresponding dermatomes. The relevance of these results to clinical practice is discussed.

Adult

The effect of an inhibitory factor from the bovine retractor penis on the gastro-intestinal tract and gall bladder of the guinea-pig.

1 The effect of a smooth muscle inhibitory factor extracted from the bovine retractor penis has been examined on a variety of in vitro smooth muscle preparations from the guinea-pig alimentary canal and on the guinea-pig gall bladder. 2 The inhibitory factor caused relaxation of spontaneous and carbachol-induced tone in the taenia coli, the stomach fundal strip and the duodenum and colon. There was little effect on the ileum. Sensitivity was highest in the taenia coli where the response to the inhibitory factor mimicked the response to stimulation of the non-adrenergic, non-cholinergic (NANC) inhibitory nerves. 3 In the taenia coli the inhibitory response to stimulation of the NANC nerves and to ATP was abolished by apamin 5 x 10(-8) M, whereas this or higher concentrations had no effect on the response to the inhibitory factor. This makes it unlikely that the latter is the neurotransmitter in these NANC nerves. 4 The inhibitory factor had no effect on the gall bladder. Inhibitory responses to field stimulation were obtained in this tissue but these were insensitive to tetrodotoxin in concentrations greater than those needed to block the motor cholinergic nerves.

Adenosine Triphosphate

The effect of morphine and some other narcotic analgesics on brain tryptophan concentrations.

An acute dose of morphine increased brain tryptophan in mice. This effect was not prevented by naloxone nor was it produced by other narcotic analgesics. Dextrorphan, but not levorphanol, had a similar effect to morphine. A large dose of tryptophan had no effect on the antinociceptive action of morphine in mice. Morphine increased brain tryptophan in rats. This effect was prevented by naloxone. A large dose of tryptophan antagonised the antinociceptive action of morphine in the rat.

Analgesics, Opioid