Anaesthesia and intensive care
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Anaesth Intensive Care · Mar 2012
Review Meta AnalysisPrevention of gastrointestinal bleeding due to stress ulceration: a review of current literature.
Our objective was to audit our current stress ulcer prophylaxis protocol (routine prescription of ranitidine and early enteral feeding) by identifying whether routine prescription of histamine-2 receptor antagonists or proton pump inhibitors as prophylaxis against stress-related mucosal disease and subsequent upper gastrointestinal bleeding is supported in the literature. We also aimed to ascertain what literature evidence supports the role of early enteral feeding as an adjunctive prophylactic therapy, as well as to search for burn-patient specific evidence, since burn patients are at high risk for developing this condition, with the aim of changing our practice. PubMed and Cochrane databases were searched for relevant articles, yielding seven randomised controlled trials comparing histamine-2 receptor antagonists and proton pump inhibitors in the prevention of upper gastrointestinal bleeding associated with stress-related mucosal disease and three separate meta-analyses. ⋯ However, enteral feeding was found to be safe and effective in preventing clinically significant upper gastrointestinal bleeding. Patients able to tolerate feeds demonstrated no additional benefit with concomitant pharmacological prophylactic therapy. Since all burn patients at the Royal Adelaide Hospital are fed from very early in their admission, the literature suggests that we, like our intensive care unit colleagues, should abolish our reliance on pharmacological prophylaxis, the routine prescription of which is not supported by the evidence.
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We undertook a systematic review to determine the optimal dose of oxytocin after elective caesarean section or caesarean section in labouring women. We identified seven trials. These trials raise questions about the use of high dose (10 international units; IU) or moderate dose (5 IU) oxytocin in both settings and provide evidence that lower doses are equally effective but associated with significantly fewer side-effects. ⋯ For the labouring parturient a slow 3 IU bolus of oxytocin, followed by an infusion of 5 to 10 IU.h(-1) for four hours is supported by limited evidence. These doses represent a starting point in the control of postpartum haemorrhage after caesarean section and do not reduce the need for mandatory active observation of the clinical situation, to detect situations that require additional doses of oxytocin or other uterotonic drugs. These doses of oxytocin minimise the risk of adverse haemodynamic changes as well as the unpleasant side-effect of nausea.
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Anaesth Intensive Care · Mar 2012
ReviewHistamine-releasing and allergenic properties of opioid analgesic drugs: resolving the two.
Opioid analgesics are amongst the most commonly administered drugs in hospitals. Whether natural or synthetic, they show some common structural features, morphine-like pharmacological action and binding specificity for complementary opioid receptors. Tramadol differs from the other opioid analgesics in possessing monoaminergic activity in addition to its affinity for the µ opioid receptor. ⋯ Despite their heavy use and occasional apparent anaphylactic-like side-effects, immunoglobulin E antibody-mediated immediate hypersensitivity reactions to the drugs are not often encountered. Uncertainties associated with skin testing with these known histamine-releasers, and the general unavailability of opioid drug-specific immunoglobulin E antibody tests contribute to the frequent failure to adequately investigate and establish underlying mechanisms of reactions by distinguishing anaphylactoid from true anaphylactic reactions. Clinical implications for diagnosis of reactions and some speculations on the rarity of true Type 1 allergies to these drugs are presented.
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Anaesth Intensive Care · Mar 2012
ReviewRespiratory dysfunction in ventilated patients: can inspiratory muscle training help?
Respiratory muscle dysfunction is associated with prolonged and difficult weaning from mechanical ventilation. This dysfunction in ventilator-dependent patients is multifactorial: there is evidence that inspiratory muscle weakness is partially explained by disuse atrophy secondary to ventilation, and positive end-expiratory pressure can further reduce muscle strength by negatively shifting the length-tension curve of the diaphragm. Polyneuropathy is also likely to contribute to apparent muscle weakness in critically ill patients, and nutritional and pharmaceutical effects may further compound muscle weakness. ⋯ There is recent evidence that inspiratory muscle training is safe and feasible in selected ventilator-dependent patients, and that this training can reduce the weaning period and improve overall weaning success rates. Extrapolating from evidence in sports medicine, as well as the known effects of inspiratory muscle training in chronic lung disease, a theoretical model is proposed to describe how inspiratory muscle training enhances weaning and recovery from mechanical ventilation. Possible mechanisms include increased protein synthesis (both Type 1 and Type 2 muscle fibres), enhanced limb perfusion via dampening of a sympathetically-mediated metaboreflex, reduced lactate levels and modulation of the perception of exertion, resulting in less dyspnoea and enhanced exercise capacity.