Anaesthesia and intensive care
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Anaesth Intensive Care · Sep 2008
Antimicrobial effects of two anaesthetic agents: dexmedetomidine and midazolam.
Some anaesthetic agents are known to inhibit microbial growth. The aim of this in vitro study was to investigate possible antimicrobial effects of two frequently used agents in intensive care units, dexmedetomidine and midazolam. Antimicrobial effect was tested on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa by broth microdilution method. ⋯ Midazolam had inhibitor and bactericidal effects on S. aureus and E. faecalis. Dexmedetomidine had only inhibitor effects on S. aureus, E. coli and P aeruginosa. Further studies are needed to determine the antimicrobial mechanisms and clinical applications.
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Anaesth Intensive Care · Sep 2008
Clinical TrialNon-invasive cardiac output measurement using a fast mixing box to measure carbon dioxide elimination.
This study investigated the accuracy of a new technique for measuring cardiac output using the derivative Fick principle based on the ratio of change in the partial pressures of end-tidal and mixed expired carbon dioxide produced by short periods of partial rebreathing. A prospective clinical study involving 24 patients following cardiopulmonary bypass for coronary artery bypass grafting or valvular surgery was undertaken in the intensive care unit of a university-affiliated hospital. Haemodynamic measurements were performed after admission to the intensive care unit. ⋯ Cardiac output measurement using the new technique demonstrated a significant but consistent underestimate, with a bias of -0.60 +/- 0.87 l/min. This new adaptation of the partial rebreathing technique is reliable in measuring cardiac output in postoperative patients. Reasons for the consistent discrepancy between thermodilution and partial rebreathing techniques are discussed.
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Anaesth Intensive Care · Sep 2008
Analgesic efficacy using loss of resistance to air vs. saline in combined spinal epidural technique for labour analgesia.
Identification of the epidural space is often performed using the loss of resistance technique to either air or saline. We sought to investigate if the medium used affected the quality of analgesia obtained by parturients who received labour epidurals. We conducted a retrospective audit of labour epidurals performed on nulliparous parturients in our institution from May 2003 to March 2005. ⋯ However patients in the air group had a higher incidence of recurrent breakthrough pain P = 0.023). We also identified three other factors that were associated with an increased incidence of recurrent breakthrough pain; administration of pre-block oxytocin, sitting position of the parturient during the procedure and the use of intrathecal bupivacaine for induction of analgesia. Our findings suggest that a loss of resistance to air is associated with a higher incidence of recurrent breakthrough pain among parturients who received combined spinal epidural analgesia for labour than a loss of resistance to saline.
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Anaesth Intensive Care · Sep 2008
Meta AnalysisUse of isotonic sodium bicarbonate to prevent radiocontrast nephropathy in patients with mild pre-existing renal impairment: a meta-analysis.
Acute renal dysfunction after radiocontrast in patients with pre-existing renal impairment is not uncommon and is associated with significant morbidity and mortality. Isotonic sodium bicarbonate solution was first reported to reduce radiocontrast nephropathy in 2004. This first study was, however; limited by its small sample size and as such, the use of isotonic sodium bicarbonate to prevent radiocontrast nephropathy is still not widely used by many anaesthetists and intensivists. ⋯ The incidence of acute renal failure requiring dialysis was low (1.4%) and was not significantly different after the use of isotonic sodium bicarbonate (relative risk 0.59, 95% CI: 0.15 to 2.42, P = 0.47; F = 0%). With the limited data available, isotonic sodium bicarbonate appears to be safe and very effective in reducing radiocontrast nephropathy in patients with mild pre-existing renal impairment. A large randomised controlled study is needed to confirm whether isotonic bicarbonate can improve patient centred clinical outcomes.
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Anaesth Intensive Care · Sep 2008
Randomized Controlled Trial Comparative StudyComparison of 2% lignocaine with adrenaline and fentanyl, 0.75% ropivacaine and 0.5% levobupivacaine for extension of epidural analgesia for urgent caesarean section after low dose epidural infusion during labour.
Low dose local anaesthetic and fentanyl epidural solutions are commonly 'topped-up' for urgent caesarean section. However, the block characteristics associated with newer local anaesthetics such as ropivacaine 0.75% and levobupivacaine 0.5% have not been fully determined. In a randomised double-blinded controlled clinical trial, we compared 2% lignocaine with adrenaline and fentanyl (LAF), 0.75% ropivacaine and 0.5% levobupivacaine for extension of low dose epidural analgesia for urgent caesarean section in 90 Asian parturients. ⋯ Levobupivacaine provided a longer duration of sensory block compared to LAF but a similar duration to 0.75% ropivacaine. Under the conditions of this study there was no significant difference in time to surgical readiness (defined as loss of sensation to cold to T4) between LAF, 0.75% ropivacaine and 0.5% levobupivacaine groups. Ropivacaine and levobupivacaine are suitable alternatives for extending epidural analgesia for urgent caesarean section.