Anaesthesia
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Randomized Controlled Trial Clinical Trial
A simple method for the maintenance of oxygen saturation following intravenous induction of anaesthesia with propofol.
One hundred unpremedicated fit adult patients having elective minor day-stay surgery and general anaesthesia were randomly allocated to one of two groups. During 30 s of intravenous propofol administration (2.5 mg.kg-1), study group patients (n = 50) were instructed to take three vital capacity breaths of room air, whilst control group patients (n = 50) were given no specific instructions. Pulse oximetry was continuously recorded over the next 5 min and the lowest oxygen saturation was noted. ⋯ Oxygen saturation returned to the pre-induction value significantly earlier in the study group patients compared with controls (97 s vs 135 s, p < 0.01). These results demonstrate that significant desaturation occurs in patients following intravenous induction of anaesthesia with propofol. This desaturation may be attenuated by asking patients to take three vital capacity breaths of room air during induction of anaesthesia.
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Randomized Controlled Trial Clinical Trial
The addition of triamcinolone acetonide to bupivacaine has no effect on the quality of analgesia produced by ilioinguinal nerve block.
In a study of 30 men undergoing elective inguinal hernia repair under general anaesthesia no difference in postoperative pain, patient rating score or morphine consumption was found between patients who had pre-operative ilioinguinal nerve block with bupivacaine 0.5% plain and those who received a similar block with bupivacaine 0.5% plain and triamcinolone acetonide 40 mg. Mean (SD) morphine requirements using a patient-controlled analgesia system were 37 (22.2) mg and 32 (20.3) mg in the bupivacaine and bupivacaine/triamcinolone groups respectively (p > 0.05). The addition of triamcinolone 40 mg to bupivacaine 0.5% offers no advantages over unsupplemented bupivacaine when used for ilioinguinal block.
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An obstetric epidural performed for analgesia showed a changing pattern of neurological block. The original features suggestive of a subdural block were complicated when aspiration of cerebrospinal fluid from the catheter became possible. Subsequent management as a continuous subarachnoid catheter allowed delivery.
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Cardiorespiratory changes induced by pneumoperitoneum and head-up tilt may generate alveolar ventilation to perfusion ratio changes and increased systemic vascular resistances. The reliability of end-tidal carbon dioxide tension and pulse oximetry in predicting arterial carbon dioxide partial pressure and arterial oxygen saturation may therefore be affected. The 35 ASA 1-2 patients in this study comprised 12 men and 23 women aged 48 (SD 17) years and weighing 71 (SD 14) kg. ⋯ This gradient was highly correlated with arterial carbon dioxide partial pressure (p < 0.0001), but was not correlated with elapsed time, intra-abdominal pressure or head-up tilt. Arterial oxygen saturation was always greater than 95% in all patients and the arterial oxygen saturation-pulse oximetric saturation gradient was always less than or equal to +4%. In conclusion, end-tidal carbon dioxide partial pressure and pulse oximetric saturation allow reliable monitoring of arterial carbon dioxide partial pressure and arterial oxygen saturation in the absence of pre-existing cardiopulmonary disease and/or acute peroperative disturbance.
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Hyperbaric oxygen treatment may require the concurrent administration of drugs. A study was performed to assess the suitability of the infusor device from the Baxter Patient-Controlled Analgesia system, for drug delivery during hyperbaric therapy. Thirty infusor devices were used to deliver 5% dextrose, 50% dextrose or propofol solutions under conditions 1 and 2.3 atmospheres of pressure. The increased pressure caused an increase in flow of 4.27%, 1.79% and 9.84% for 5% dextrose, propofol and 50% dextrose respectively.