British journal of anaesthesia
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Hypotensive anaesthesia does not impair renal function after surgery in normal patients but there are no reports of hypotensive anaesthesia in patients with chronic renal dysfunction (CRD). ⋯ HEA, per se, when carefully managed does not appear to predispose patients with CRD to acute renal failure after THR.
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We developed a non-invasive, continuous, high-resolution method of measuring carboxyhaemoglobin fraction (COHb%) using expiratory gas analysis (EGA). We assessed whether application of EGA to carboxyhaemoglobin dilution provides red cell volume (RCV) measurement with accuracy equivalent to that of CO-haemoximetry, with a smaller infusion volume of carbon-monoxide-saturated autologous blood (COB). Method. We assessed the agreement between repeated COHb% measurements by EGA and simultaneous measurement by CO-haemoximetry, using Bland and Altman plot, in healthy subjects and patients with artificially controlled ventilation and no radiological evidence of pulmonary oedema or atelectasis. We assessed the agreement between RCV measurements by EGA with infusion of 20 ml of COB (RCVEGA) and RCV measurements by CO-haemoximetry with infusion of 100 ml of COB (RCVHEM), in healthy subjects. ⋯ EGA provided non-invasive, accurate, continuous, high-resolution COHb% measurements. Applying EGA to carboxyhaemoglobin dilution, we achieved RCV measurements with accuracy equivalent to that of CO-haemoximetry, with one-fifth of the COB infusion volume. However, clinical application of the method is limited to patients with no radiological evidence of pulmonary oedema or atelectasis.
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The transient effects of epidural bupivacaine 0.25-0.5% on the Doppler velocimetry of umbilical and uterine arteries had been reported, but the effects of continuous lower dose epidural bupivacaine (0.05-0.1%) infusion for labour analgesia have never been reported. In this study, we evaluated the effects of continuous epidural bupivacaine 0.075% on the Doppler velocimetry of uterine arteries. ⋯ Continuous epidural analgesia with bupivacaine 0.075% increases the resistance of uterine artery and therefore possibly reduces the uterine blood flow.
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Case Reports
Epidural haematoma after a combined spinal-epidural anaesthetic in a patient treated with clopidogrel and dalteparin.
We report a case of a spinal-epidural haematoma occurring in a patient after a combined spinal-epidural anaesthetic. She had been taking clopidogrel and had received perioperative dalteparin for thromboprophylaxis. Despite adhering to standard guidelines concerning administration of low molecular weight heparin perioperatively and stopping the clopidogrel 7 days before the anaesthetic, the patient developed an epidural haematoma.
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Although N(2)O has been widely used as an anaesthetic adjuvant its effect on electroencephalographic (EEG) activity is poorly understood because it is usually studied in the presence of additional anaesthetics, including inhaled anaesthetics. We examined the EEG effects of N(2)O in rats using a hyperbaric chamber that permitted N(2)O to be the sole anaesthetic. ⋯ These data indicate that N(2)O at peri-MAC partial pressures prevents EEG activation resulting from noxious electrical stimulation. Unlike the situation with isoflurane, stimulus-evoked EEG activation did not occur at peri-MAC anaesthetic concentrations, suggesting that N(2)O potently blocked ascending nociceptive transmission.