Anaesthesia
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Randomized Controlled Trial
The effects of dexmedetomidine on inflammatory mediators after cardiopulmonary bypass.
Cardiac surgery with cardiopulmonary bypass is associated with the development of a systemic inflammatory response that can often lead to dysfunction of major organs. We hypothesised that the highly selective α2-adrenergic agonist, dexmedetomidine, attenuates the systemic inflammatory response. Forty-two patients were randomly assigned to receive dexmedetomidine or saline after aortic cross-clamping). ⋯ In the dexmedetomidine group, the levels increased significantly only during cardiopulmonary bypass (4.0 (1.9) ng ml(-1) baseline vs. 10.8 (2.7) ng ml(-1) ) but not after (7.4 (3.8) ng ml(-1) ). Dexmedetomidine infusion also suppressed the rise in mean (SD) interleukin-6 levels after cardiopulmonary bypass (a rise of 124.5 (72.0) pg ml(-1) vs. 65.3 (30.9) pg ml(-1)). These suppressive effects of dexmedetomidine might be due to the inhibition of nuclear factor kappa B activation and suggest that intra-operative dexmedetomidine may beneficially inhibit inflammatory responses associated with ischaemia-reperfusion injury during cardiopulmonary bypass.
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The endothelial glycocalyx is an important part of the vascular barrier. The glycocalyx is intimately linked to the homoeostatic functions of the endothelium. Damage to the glycocalyx precedes vascular pathology. ⋯ In the second part, we have systematically reviewed interventions to protect or repair the glycocalyx. Glycocalyx damage can be caused by hypervolaemia and hyperglycaemia and can be prevented by maintaining a physiological concentration of plasma protein, particularly albumin. Other interventions have been investigated in animal models: these require clinical research before their introduction into medical practice.
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The Tulip airway is an adult, disposable, single-sized oropharyngeal airway, that is connectable to an anaesthetic circuit. After a standardised induction of anaesthesia in 75 patients, the ease of insertion, intracuff pressure and intracuff volume were measured, as were the end-tidal carbon dioxide levels, airway pressures and tidal volumes over three breaths. Successful first-time insertion was achieved in 72 patients (96%, CI 88.8-99.2%) and after two attempts in 74 patients (99%, CI 92.8-100%). ⋯ In 60 patients (80%, CI 72.2-90.4%), the Tulip airway provided a patent airway without additional manoeuvres, but in 14 patients, jaw thrust or head extension was necessary for airway patency. The main need for these adjuncts appeared to be an initial under-inflation of the cuff. These promising results are consistent with recent manikin studies using this device.
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The Confidential Enquiries into Maternal Deaths in the UK have recommended obstetric early warning systems for early identification of clinical deterioration to reduce maternal morbidity and mortality. This survey explored early warning systems currently used by maternity units in the UK. An electronic questionnaire was sent to all 205 lead obstetric anaesthetists under the auspices of the Obstetric Anaesthetists' Association, generating 130 (63%) responses. ⋯ Respondents agreed that the six most important physiological parameters to record were respiratory rate, heart rate, temperature, systolic and diastolic blood pressure and oxygen saturation. One hundred and eighteen (91%) lead anaesthetists agreed that early warning systems helped to prevent obstetric morbidity. Staffing pressures were perceived as the greatest barrier to their use, and improved audit, education and training for healthcare professionals were identified as priority areas.
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We have developed an ultrasound probe through the centre of which an epidural needle can pass, intended to reduce the rate of contact between bone and needle during epidural insertion. We tested the ability of this probe to identify the lumbar interspace, using A-mode ultrasound, in a submerged plastic model, a porcine phantom and five human volunteers. ⋯ The human study also showed that the maximum bone echo was at least three times stronger than the interspace echo. Axial ultrasound guidance, with the needle passing through the probe, offers a method for reducing bone contact during epidural insertion.