Anaesthesia
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Drawing samples from an indwelling arterial line is the method of choice for frequent blood analysis in adult critical care areas. Sodium chloride 0.9% is the recommended flush solution for maintaining the patency of arterial catheters, but it is easy to confuse with glucose-containing bags on rapid visual examination. The unintentional use of a glucose-containing solution has resulted in artefactually high glucose concentrations in blood samples drawn from the arterial line, leading to insulin administration causing hypoglycaemia and fatal neuroglycopenic brain injury. ⋯ We also make recommendations about storage, arterial pressure monitoring and sampling systems and techniques. Finally, we make recommendations about glucose monitoring and insulin administration. It is intended that adherence to these guidelines will reduce the frequency of sample contamination errors in arterial line use and capture events, when they do occur, before they cause patient harm.
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Ropivacaine plasma levels following local infiltration analgesia for primary total hip arthroplasty.
We measured total and free plasma concentrations of ropivacaine following high-volume, high-dose local infiltration analgesia in 19 patients aged 65 years or over undergoing unilateral total hip arthroplasty. The patients received 180 ml ropivacaine 0.2% (360 mg), which was injected into the deep and peri-capsular tissues, the gluteal muscles and fascia lata, and the subcutaneous tissues and skin. Patients were monitored for clinical symptoms and signs of systemic local anaesthetic toxicity. ⋯ No samples reached the toxic threshold for venous ropivacaine concentration, although four patients exhibited mild symptoms consistent with local anaesthetic toxicity. One patient had episodes of complete heart block on ECG monitoring, but plasma ropivacaine levels were below toxic levels. We conclude that plasma levels for ropivacaine associated with toxicity in a volunteer population (total 2.2 μg.ml(-1) , free 0.15 μg.ml(-1) ) are not reached during local infiltration analgesia for hip arthroplasty in elderly patients.