Anaesthesia
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Caudal epidural injection is a simple procedure that carries a low risk of complications. The whoosh test (injection of air into the caudal epidural space with simultaneous auscultation over the thoracolumbar spine) has been recommended as an aid to correct needle placement. A 1-year prospective study, using fluoroscopic imaging to identify needle position, was conducted to compare the sensitivity and specificity of the whoosh test with that of clinical impression alone in assessing correct needle placement in the caudal space. ⋯ Clinical impression alone had a sensitivity of 94% and a specificity of 20%. The whoosh test had a sensitivity of 80% and a specificity of 60%. The whoosh test is superior to clinical judgment in detecting incorrect caudal needle placement.
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Clinical Trial
Use of the Combitube for airway maintenance during percutaneous dilatational tracheostomy.
The Combitube airway allows short-term ventilation during cardiopulmonary resuscitation and can be useful in the management of the difficult airway. In a prospective observational study we assessed its use during percutaneous dilatational tracheostomy (PDT). Twenty-one intensive care patients scheduled for elective PDT had their tracheal tube replaced by a Combitube airway retaining the same ventilator settings. ⋯ A high mean (SD) transmural pressure of 14.7 (5) kPa was exerted by the distal cuff. The Combitube provided a satisfactory alternative airway to the tracheal tube during performance of PDT in 85% of our patients. Potential problems associated with its use in intensive care patients are outlined.
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We report a case of Streptococcus salivarius meningitis following combined spinal-epidural analgesia for labour. Although rare, bacterial meningitis following combined spinal-epidural anaesthesia is being increasingly described. We review the previously reported cases and discuss the possible aetiological causes and the aseptic precautions likely to reduce the incidence of infectious complications.
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Five hundred members of the Obstetric Anaesthetists Association were surveyed regarding their technique for identification of the epidural space. Eighty-one per cent of the questionnaires were returned completed. Fifty-nine per cent of respondents first learned a loss of resistance to air technique, 33.4% to saline and 7.4% another technique. ⋯ Twenty-eight per cent taught a loss of resistance to air, 57.2% taught a loss of resistance to saline and 12.9% taught both techniques. Twenty-three per cent changed from a loss of resistance to air, to a saline technique, and 4.2% vice versa. Forty-seven per cent of those using air felt that loss of resistance to air was not associated with a clinically significant difference in the incidence of accidental dural puncture compared with saline.
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A spreadsheet model of a circle breathing system and a 70-kg anaesthetised 'standard man' has been used to simulate the first 20 min of low-flow anaesthesia with halothane, enflurane, isoflurane, sevoflurane and desflurane in oxygen. It is shown that, with the fresh-gas flow set initially equal to the total ventilation and the fresh-gas partial pressure to 3 MAC, the end-expired partial pressure can be raised to 1 MAC in 1 min with desflurane and sevoflurane, 1.5 min with isoflurane, 2.5 min with enflurane and 4 min with halothane. Sequences of lower fresh-gas flow and partial pressure settings are given for then maintaining 1 MAC end-expired partial pressure, with a minimum usage of anaesthetic, e.g. 13 ml of liquid desflurane in 20 min (of which only 33% is taken up by the patient) if the minimum acceptable flow is 11.min-1, or 8 ml (with 57% in the patient) if the minimum is 250 ml.min-1.