Anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Intra-operative patient-controlled sedation. Comparison of patient-controlled propofol with anaesthetist-administered midazolam and fentanyl.
The quality of sedation and postoperative recovery have been assessed for intra-operative sedation provided by either patient-controlled sedation with propofol or a standard method using divided doses of midazolam and fentanyl, in 40 ASA 1 day surgery patients undergoing extraction of third molar teeth under local analgesia. Patient-controlled sedation with propofol produced sedation no deeper than full eyelid closure with prompt response to verbal command, but deeper levels were seen in three patients in the midazolam and fentanyl group. Patient satisfaction was higher in the patient-controlled sedation propofol group for both subjective intra-operative feelings (p less than 0.01) and willingness to have the procedure again in the same manner (p less than 0.05). ⋯ Drug dose was correlated with duration of procedure and surgical difficulty in the patient-controlled sedation propofol group but not in the midazolam and fentanyl group. Postoperative testing included a new computerised test, the FAST index, which indicated a dose-dependent reduction in cognitive function in the midazolam and fentanyl group, which persisted until the time of discharge. Changes in cognitive function in the patient-controlled sedation propofol group in the same postoperative interval were significantly less and not related to propofol dose.
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A case is reported in which chemical meningism occurred after lumbar facet joint block with methylprednisolone acetate and bupivacaine. This complication was probably due to inadvertent dural puncture. The use of steroids in facet joint injections is questioned.
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A preliminary study was performed to calculate the cost of intensive therapy on an individual patient basis. The fixed (equipment, supporting services and land opportunity), semi-fixed (staff) and marginal (treatment) costs of 20 critically ill patients were calculated individually. The results show that there is wide variation in intensive therapy costs. ⋯ The mean total cost per patient was 1980 pounds, but the cost per survivor increased by 16% (347 pounds) because of four deaths on the intensive care unit. High total costs are associated with increased severity of illness and higher marginal (treatment) costs are associated with increased semi-fixed (staff) costs. The cost of intensive therapy was three to five times that for general ward care.
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The relationship between peak airway pressure, alveolar pressure and respiratory frequency was calculated for the range of compliances and airway resistances which might be encountered during mechanical ventilation of a 3-kg neonate. The pressure/flow relationships of 2.5, 3.0, 3.5 and 4-mm tracheal tubes were determined at a series of flows from 0.5 to 4 litres/minute. ⋯ Large differences between peak airway and alveolar pressures developed when frequency was increased or inspiratory time decreased; the differences were greatest with the smaller tubes. Shortening expiratory time by increasing the frequency or altering the inspiratory:expiratory ratio resulted in increased end-expiratory pressure because of incomplete emptying of the lung.
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Unexpected difficulty with tracheal intubation contributes to anaesthetic mortality. The laryngeal mask can almost always be placed satisfactorily and its position should facilitate blind intubation. A 6-mm cuffed tube will pass through both adult sizes of the mask and this study tested the feasibility of intubation through the mask. ⋯ Intubation via the laryngeal mask was attempted in 100 routine patients: of the first 50 (group 1, no cricoid pressure), 45 (90%) were successfully intubated. Maintenance of cricoid pressure throughout the manoeuvre (group 2) reduced the success rate significantly to 56% (p less than 0.05). Despite the possibility that cricoid pressure may have to be interrupted momentarily, the ease with which the technique can be learnt, and the immediate availability of the necessary apparatus suggest that it should be considered for inclusion in failed intubation drill.