Anaesthesia
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Multi-lumen extensions used to infuse multiple fluids via a single intravenous cannula might increase resistance and so limit the flow that can be achieved. We constructed low-pressure and high-pressure models and compared the effect of two different multi-lumen extensions on flow rate. Both multi-lumen extensions reduced flows by up to 76% (p < 0.001). ⋯ Multi-lumen extensions can therefore significantly impede fluid flow, and should be avoided or removed when rapid infusion is required. These effects are less important in paediatric anaesthesia where smaller cannulae are used. Manufacturers should include internal diameter or flow effects on the packaging of these extensions to assist clinicians in making such decisions.
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We investigated changes in concentrations of interleukin-1β, interleukin-6, tumour necrosis factor-α and bradykinin in blood during passage through a cell salvage device and a leucocyte depletion filter, with or without application of subatmospheric pressure across the filter. Blood samples from 19 healthy women undergoing scheduled caesarean section showed concentrations of cytokines and bradykinin in blood filtered under gravity flow that were equal to or significantly lower than those of pre-operative venous blood samples. They were also significantly lower than that in postoperative orthopaedic shed blood, which is commonly reinfused after orthopaedic surgery. ⋯ We suggest that use of a leucocyte depletion filter for cell-salvaged blood with gravity flow is likely to be safe with regard to concentrations of cytokines and bradykinin. However, this may not hold true for the filter used with subatmospheric pressure. If transfusion of salvaged blood using a leucocyte depletion filter seems to induce hypotension, elevation of interleukin-6 should be suspected.
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Chlorhexidine contamination of equipment used in central neuraxial anaesthesia has been implicated in causing adhesive arachnoiditis. We measured the extent of chlorhexidine splash during pouring into a gallipot (antiseptic skin preparation container) from heights of 5 cm, 10 cm, 15 cm and 20 cm. Twenty experiments were performed at each height. ⋯ The 40-cm radius measurement area was divided into 5-cm-wide zones to assess spread. At pouring heights of 15 cm and 20 cm, all zones were contaminated. These results demonstrate that pouring chlorhexidine into a gallipot generates significant splash, and we recommend that this should be avoided near equipment used for neuraxial anaesthesia.