Anaesthesia
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Randomized Controlled Trial Clinical Trial
Intravenous lignocaine and sympathoadrenal responses to laryngoscopy and intubation. The effect of varying time of injection.
We have studied the effect of varying the timing of a prior dose of intravenous lignocaine 1.5 mg/kg on the cardiovascular and catecholamine responses to tracheal intubation. Forty healthy patients were given an intravenous injection of either placebo or lignocaine 2, 3 or 4 minutes before tracheal intubation. There was a significant increase in heart rate of 21-26% in all groups. There was no significant increase in mean arterial pressure in response to intubation in any group of patients given lignocaine before intubation, but in the placebo group, mean arterial pressure increased by 19.1% compared to baseline values (p less than 0.05).
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Review Comparative Study
Potential errors in pulse oximetry. II. Effects of changes in saturation and signal quality.
The published studies of pulse oximeter performance under conditions of normal, high and low saturation, exercise, poor signal quality and cardiac arrhythmia are reviewed. Most pulse oximeters have an absolute mean error of less than 2% at normal saturation and perfusion; two-thirds have a standard deviation (SD) of less than 2%, and the remainder an SD of less than 3%. Some pulse oximeters tend to read 100% with fractional saturations of 97-98%. ⋯ Ear oximetry may be inaccurate during exercise. Low signal quality can result in failure to present a saturation reading, but data given with low signal quality warning messages are generally no less accurate than those without. Cardiac arrhythmias do not decrease accuracy of pulse oximeters so long as saturation readings are steady.
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Case histories are reported of three patients who had large retrosternal goitres which were responsible for significant abnormalities of the airway. Computerised axial tomography demonstrated the exact anatomy. The site of tracheal compression was shown and accurate measurements of the diameter of the trachea at its narrowest point were made. This information was useful when the management of the patient was planned.
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The neurological assessment of patients admitted to the intensive care unit after successful resuscitation from cardiopulmonary arrest may be difficult. We describe the cases of two patients who developed myoclonus within 24 hours of hypoxic respiratory and cardiac arrest. Initially, the clonic movements were thought to be generalised convulsions and were treated as such, until it became evident that the patients were aware and distressed. ⋯ Recognition depends on the awareness that the syndrome exists, and is important so that correct therapy can be instituted. There may be important prognostic implications. Both our patients had normal intellectual recovery with moderate residual neurological disability from their movement disorder.