Anaesthesia and intensive care
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Anaesth Intensive Care · Aug 1997
Randomized Controlled Trial Clinical TrialThe effect of supplemental oxygen on the incidence of hypoxaemia after premedication in patients undergoing cardiac surgery.
Opiate premedication may cause significant respiratory depression, particularly when other sedative agents such as scopolamine or benzodiazepines are added. This can cause hypoxaemia with potential for worsening myocardial ischaemia in cardiac surgery patients. The aim of this study was to investigate the incidence of hypoxaemia (SpO2 < 90%) in elective patients undergoing cardiac surgery and to assess the efficacy of supplemental oxygen in preventing it. ⋯ In patients receiving oxygen (n = 48) there were no episodes of hypoxaemia (0%). In patients not receiving oxygen (n = 46) there were 14 episodes of hypoxaemia (30%, P < 0.0001). We conclude that there is a significantly high incidence of hypoxaemia in cardiac surgery patients following combined opiate and sedative premedication and that it can be reduced by the routine administration of supplemental oxygen.
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Anaesth Intensive Care · Aug 1997
Polyurethane central venous catheters, hydrochloric acid and 70% ethanol: a safety evaluation.
Three groups of polyurethane central venous catheters (CVC) were infused daily for twenty days with 0.1 normal hydrochloric acid, 70% ethanol and normal saline (control) respectively to look for any changes in microscopic structural integrity. A 1 cm segment was cut from the distal end of each CVC daily. All sections were examined in a scanning electron microscope, looking for evidence either of damage to the lumen surface or of wall thinning. ⋯ Sporadic fine surface-pitting appeared late in the study without any clear temporal or treatment-related pattern. The mean CVC wall thickness did not change significantly over the study period (P = 0.15). Qualitative softening of ethanol treated catheters was observed, and this finding limits the recommendations for the use of ethanol. 0.1N HCl does not compromise the structural safety of the catheters, and its use should be considered when polyurethane CVC. become occluded.
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Anaesth Intensive Care · Aug 1997
Plasma lignocaine concentration following nebulization for awake intubation.
Nebulization of lignocaine is a common technique for preparing the airway prior to awake intubation. The aim of the study was to assay the serum levels of lignocaine. Ten ASA I volunteers had 6 mg/kg of 10% lignocaine solution nebulized via facemask. ⋯ No subject developed symptoms or signs of lignocaine toxicity. Peak plasma lignocaine levels were an order of magnitude below the accepted toxic threshold of 5 mg/l. This indicates that supplemental doses of lignocaine via the bronchoscope can be given with safety.