British journal of anaesthesia
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In a previous in vitro study using saline medium, the authors showed that certain drugs changed the voltages of lithium dilution cardiac output (LiDCO) sensors and also influenced their accuracy in measuring lithium concentrations. These two parameters correlated and so we examined whether such drug-sensor interaction exists when LiDCO sensor was exposed to xylazine in blood. ⋯ This study showed that exposure of a LiDCO sensor to blood after a single clinically relevant dose of xylazine in horses changed the voltages of the sensors for 15 min. Comparison of saline- and blood-exposed sensor voltages could become a tool to detect drug-sensor interactions.
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Randomized Controlled Trial
Crystalloid or colloid for goal-directed fluid therapy in colorectal surgery.
Goal-directed fluid therapy has been shown to improve outcomes after colorectal surgery, but the optimal type of i.v. fluid to use is yet to be established. Theoretical advantages of using hydroxyethyl starch (HES) for goal-directed therapy include a reduction in the total volume of fluid required, resulting in less tissue oedema. Recent work has demonstrated that new generations of HES have a good safety profile, but their routine use in the perioperative setting has not been demonstrated to confer outcome benefit. ⋯ Goal-directed fluid therapy is possible with either crystalloid or HES. There is no evidence of a benefit in using HES over crystalloid, despite its use resulting in a lower 24 h fluid balance.
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Positioning central venous catheters (CVCs) in the proper part of the superior vena cava (SVC) is difficult. The aim of this exploratory study was to analyse topographic relationships of the extrapericardial SVC using chest X-ray (CXR) and computed tomography (CT). This included an appraisal of rules for optimal CVC tip placement. ⋯ The extrapericardial part of the SVC varies considerably in length and position, and rules of thumb based on anatomical landmarks should be used cautiously. In our series, using 85% of the SCJ-to-carina distance or placing the CVC tip 9 mm above the carina would have resulted in a high percentage of positions in the extrapericardial SVC.
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Positive pressure ventilation in patients with a bronchopleural fistula (BPF) is associated with variable, unpredictable gas leaks that can impair gas exchange. The optimum settings for high-frequency jet ventilation in this scenario are unclear. We investigated flow dynamics with BPFs of 2 and 10 mm, at various positions and with different jet ventilator settings in a bench-top model. ⋯ These data suggest that gas leak will be minimized and ventilator volumes maintained during jet ventilation using frequencies >200 min(-1) and lower driving pressures, but confirmatory clinical studies are required. Values displayed by the jet ventilator are unreliable.