Anaesthesia
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Comparative Study Clinical Trial Controlled Clinical Trial
The palpation of pulses.
In 554 anaesthetised patients, the times taken to separately palpate and identify each of the carotid, radial, brachial and femoral pulses were recorded. The patients were divided into three groups based on the form of airway management chosen (tracheal tube, facemask or laryngeal mask airway). ⋯ The carotid pulse was not so easily identified, requiring 10 s to enable an identification rate of greater than 95%. The presence of a laryngeal mask airway or a tracheal tube did not hinder the identification of carotid pulse.
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Randomized Controlled Trial Clinical Trial
Enhancement of pressor response to ephedrine following clonidine medication.
We studied pressor responses and changes in plasma catecholamine concentrations following two consecutive doses of ephedrine 0.1 mg.kg-1 with (n = 20) and without (n = 20) clonidine 5 micrograms.kg-1 premedication in patients presenting for a variety of major surgical procedures under general anaesthesia. Arterial blood pressure and heart rate were measured at 1 min intervals for 10 min, and plasma catecholamines were measured before and 3 min after each dose of ephedrine. ⋯ Plasma catecholamine concentrations tended to be lower in the clonidine group throughout the study. The augmented pressor response to ephedrine in clonidine-treated patients can be attributed to enhanced cardiovascular response rather than clonidine-induced accumulation and subsequent increased release of catecholamine.
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A 39-year-old man developed a unilateral recurrent laryngeal nerve palsy following laryngeal mask airway insertion for a day case procedure.
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We have investigated the relationship between changes in the middle latency auditory evoked potentials during alternating periods of consciousness and unconsciousness produced by propofol infusion combined with spinal anaesthesia for total knee replacement. Eleven patients completed the study, of whom two had recollection of events after the onset of the anaesthetic. ⋯ During successive transitions from unconsciousness to consciousness, awake latencies were slightly higher than those of baseline awake, whereas anaesthetised latencies were similar to the ones obtained during the first period of unconsciousness. The consistent changes demonstrated, suggest that the auditory evoked potentials could represent a reliable indicator of potential awareness during anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
Effect of intravenous fluid preload on vasoactive peptide secretion during Caesarean section under spinal anaesthesia.
The endogenous release of the vasoactive peptides atrial natriuretic peptide and endothelin-1 may modify maternal haemodynamic responses to a rapid intravenous volume load used to prevent hypotension at elective Caesarean delivery under spinal anaesthesia. Twenty-two healthy pregnant women were examined during elective Caesarean section at term pregnancy. ⋯ A slight decrease in endothelin-1 levels was found during colloid infusion. A significant increase in the release of atrial natriuretic peptide in response to volume load may decrease vascular tone and initiate diuresis, thereby attenuating the effect of volume load on blood pressure during elective Caesarean delivery.