Anaesthesia
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Fixed performance venturi devices should provide a predetermined oxygen concentration at an outflow which exceeds an adult's peak resting inspiratory flow rate (approximately 30 l.min(-1)). Campbell's original description mentioned the sensitivity of the venturi device to downstream resistance but gave no further details. This study examined outflow and oxygen concentration from the five standard venturi devices (24-60% O(2)) when downstream pressure increased. ⋯ The outflow at zero downstream pressure for the 24-40% O(2) venturi devices ranged from 40 to 50 l.min(-1) but only 2-3 mmH(2)O was needed to halve this flow and increase oxygen concentration. The 60% O(2) venturi delivered a maximum of only 30 l.min(-1) at zero downstream pressure and flow was reduced further by increasing this pressure. An increase in downstream pressure of only a few mmH(2)O increased oxygen concentration and decreased outflow of all the venturi devices tested, in most to less than normal peak tidal flow in adults.
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Practice Guideline Guideline
Difficult Airway Society guidelines for management of the unanticipated difficult intubation.
Problems with tracheal intubation are infrequent but are the most common cause of anaesthetic death or brain damage. The clinical situation is not always managed well. The Difficult Airway Society (DAS) has developed guidelines for management of the unanticipated difficult tracheal intubation in the non-obstetric adult patient without upper airway obstruction. These guidelines have been developed by consensus and are based on evidence and experience. We have produced flow-charts for three scenarios: routine induction; rapid sequence induction; and failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed, anaesthetised patient. The flow-charts are simple, clear and definitive. They can be fully implemented only when the necessary equipment and training are available. The guidelines received overwhelming support from the membership of the DAS. ⋯ It is not intended that these guidelines should constitute a minimum standard of practice, nor are they to be regarded as a substitute for good clinical judgement.
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Continuous flow positive pressure devices bridge the gap between mechanical and unsupported ventilation in patients recovering from critical illness. At this point, patients are often fully awake, yet the inflated tracheostomy cuff prevents them from speaking or swallowing. The aim of this study was to investigate the effects of cuff deflation. ⋯ All patients were able to vocalise following cuff deflation. Twelve patients passed a blue dye swallow screen within a day of tolerating cuff deflation. These results suggest that pressures fall slightly following cuff deflation but this is associated with respiratory stability and may allow patients to talk and swallow.
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Randomized Controlled Trial Clinical Trial
Evaluation of a local anaesthesia regimen following mastectomy.
Breast surgery can be emotionally distressing and physically painful. Acute pain following surgery is often related mainly to the axillary surgery and is aggravated by arm and shoulder movement. We conducted a prospective double-blind, randomised, placebo-controlled trial to determine the influence of local anaesthetic irrigation of axillary wound drains on postoperative pain during the first 24 h following a modified Patey mastectomy (mastectomy with complete axillary node clearance). ⋯ Morphine consumption, visual analogue and verbal rating pain scores were recorded. There were no statistical differences in morphine requirements or pain scores between the two groups, nor were there differences in anti-emetic or supplemental analgesic consumption. Bupivacaine irrigation used in this manner does not appear to offer an effective contribution to postoperative analgesia.