Anaesthesia
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Review Historical Article
Pharmacogenetics and anaesthesia: the value of genetic profiling.
Approximately 50 years ago, pharmacogenetics was described as a new field of medicine that may explain human drug action. Anaesthesia played a key role in the early investigations. An understanding of how a person's DNA influences drug metabolism and effectiveness may allow individually tailored prescriptions, improving outcomes and safety. ⋯ In this review, we present a selection of historical landmarks where anaesthesia has been a catalyst for pharmacogenetic development. We examine the level of evidence and cite examples of candidate genes and common polymorphisms known to alter the response to peri-operative medication. Finally, we set forth current views and potential exciting perspectives that may arise from the application of pharmacogenetics to the daily practice of anaesthesia and pain medicine.
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Randomized Controlled Trial
Limited maximal flow rate of target-controlled remifentanil infusion and induced cough.
This study evaluated the effect of limiting maximal infusion-pump flow rate on suppression of remifentanil-induced cough during target-controlled infusion. Two hundred and ten patients were randomly assigned to receive remifentanil at an effect-site concentration of 4.0 ng.ml(-1) with maximal flow rate limited to 100 (group R(100)), 200 (group R(200)), or 1200 ml.h(-1) (group R(1200)). The number of episodes of cough were recorded and graded as mild (1-2), moderate (3-4), or severe (5 or more). ⋯ Patients in group R(100) and R(200) had a significantly lower incidence of cough than those in group R(1200) (p < 0.05). Zero, two and five patients coughed a moderate amount in groups R(100), R(200) and group R(1200), respectively (p < 0.05). Limiting maximal infusion rate during remifentanil TCI suppressed remifentanil-induced cough.
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Non-technical skills are recognised as crucial to good anaesthetic practice. We designed and evaluated a specialty-specific tool to assess non-technical aspects of trainee performance in theatre, based on a system previously found reliable in a recruitment setting. We compared inter-rater agreement (multir-ater kappa) for live assessments in theatre with that in a selection centre and a video-based rater training exercise. ⋯ A subsequent assessor training exercise showed good inter-rater agreement, (mean kappa = 0.79) but did not improve performance of the assessment tool when used in round 2 (mean kappa = 0.14, G = 0.42). Inter-rater agreement in two selection centres (mean kappa = 0.61 and 0.69) exceeded that found in theatre. Assessment tools that perform reliably in controlled settings may not do so in the workplace.
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The objective of this study was to identify whether pulmonary capillary wedge pressure can be estimated in anaesthetised patients receiving mechanical ventilation, using transoesophageal echocardiography. A retrospective validation study investigated a 10-patient cohort with variable haemodynamic conditions, and a 102-patient series in which a single measurement was made during stable haemodynamic conditions. ⋯ In all cases, the limits of agreement exceeded 10 mmHg, and sensitivity or specificity for detecting wedge pressure ≥ 15 mmHg was poor. This study demonstrates proof of concept that using transoesophageal echocardiography for estimating the pulmonary artery wedge pressure may not be sufficiently accurate for clinical use.
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Dual-lumen haemodiafiltration catheters enable continuous renal replacement therapy in the critically ill and are often co-located with central venous catheters used to infuse drugs. The extent to which infusions are immediately aspirated by an adjacent haemodiafiltration catheter remains unknown. A bench model was constructed to evaluate this effect. ⋯ No tracer was aspirated from catheters infusing at least 2 cm downstream. Orientation of side ports did not affect tracer elimination. Co-location of central venous and haemodiafiltration catheters may lead to complete aspiration of infusions into the haemodiafilter with resultant drug under-dosing.