British journal of anaesthesia
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The pharmacokinetics of ropivacaine were evaluated during long-term continuous epidural analgesia (CEDA) for about 120 h. The total and free plasma concentrations of ropivacaine and the alpha1-acid glycoprotein (AAG) concentration were measured in 12 patients after total knee arthroplasty. The infusion rate was adjusted according to patients' analgesic needs or side effects. ⋯ The highest individual free plasma concentration was 0.16 microg ml(-1). The individual peak total plasma concentration, 4.1 (1.2) microg ml(-1), was achieved after 67.7 (16.5) h, although the AAG concentration increased throughout the observation period. Our data support the safety and efficacy of long-term ropivacaine CEDA.
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Randomized Controlled Trial Clinical Trial
Pre-operative oral erythromycin reduces residual gastric volume and acidity.
We investigated whether low-dose erythromycin (200 mg) given as an oral premedicant altered the residual gastric volume and its acidity in fasted patients at induction of anaesthesia in a single-blinded study. Sixty patients were allocated randomly to receive either an erythromycin tablet (200 mg) or nothing with 10 ml water 3 h before induction of anaesthesia, and another 60 patients 1 h before induction of anaesthesia. ⋯ Erythromycin significantly reduced gastric acidity when it was given 1 h before induction of anaesthesia (P<0.02; 95% CI for median pH difference: 0.1-1.7). In contrast, when given 3 h before induction of anaesthesia, erythromycin did not significantly alter acidity.
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We report a case of venous air embolism during an elective shoulder arthroscopy in which air was used as a joint distending agent. Venous air embolism was diagnosed by the sudden decrease in the end-tidal carbon dioxide concentration. ⋯ We present this case to make surgeons and anaesthetists aware of the possibility of gas/air embolism during elective arthroscopy, when gas/air is used to distend the joint. This case also illustrates that the end-tidal carbon dioxide monitor, which is part of the standard anaesthetic monitoring system, is very sensitive in detecting venous air embolism.
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Clinical Trial
Pharmacokinetics and dynamics of atracurium infusions after paediatric orthotopic liver transplantation.
We examined the pharmacokinetics and pharmacodynamics of atracurium besylate and its metabolites in children after orthotopic liver transplantation (OLT), as a suitable model for critically ill children. Ten children were studied after OLT on return to the intensive care unit (ICU). The mean (range) age was 36 (7-78) months, and weight 6-24.2 kg. ⋯ Mean recovery time on stopping the atracurium infusion to a TOF ratio >0.75 was 23.6 (12-27) min. Atracurium is an effective and safe neuromuscular blocking agent in this population. Laudanosine concentrations are not excessive if graft function is satisfactory.
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Single-injection paravertebral block offers adequate unilateral analgesia for thoracic and upper abdominal surgery. This technique is easy to learn but there is a risk, albeit low, of pleural puncture. The aim of the study was to determine whether sonographic measurements of the distances from the skin to the transverse process and to the parietal pleura are useful for calculating the required depth of needle insertion. ⋯ Puncture of the paravertebral space failed in one obese woman. There was a very close correlation between needle insertion depth from the skin to the transverse process and the distance measured by ultrasound if angle correction was used (adjusted r2=0.95). Similarly, there was excellent correlation between the angle-corrected ultrasound distance from the skin to the parietal pleura and the distance from the skin to the paravertebral space (adjusted r2=0.92).