British journal of anaesthesia
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Neutralisation of systemic anticoagulation with heparin in cardiac surgery with cardiopulmonary bypass requires protamine administration. If adequately dosed, protamine neutralises heparin and reduces the risk of postoperative bleeding. However, as its anticoagulant properties are particularly exerted in the absence of heparin, overdosing of protamine may contribute to bleeding and increased transfusion requirements. ⋯ The available evidence suggests that protamine dosing should not exceed a protamine-to-heparin ratio of 1:1. In particular, protamine-to-heparin dosing ratios >1 are associated with more postoperative 12 h blood loss. The optimal protamine-to-heparin ratio in cardiac surgery has, however, not yet been elaborated, and may vary between 0.6 and 1.0 based on the initial heparin dose.
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Both anaemia and blood transfusion are associated with poor outcomes in the neurosurgical population. Based on the available literature, the optimal haemoglobin concentration for neurologically injured patients appears to be in the range of 9.0-10.0 g dl-1, although the individual risks and benefits should be weighed. Several perioperative blood conservation strategies have been used successfully in neurosurgery, including correction of anaemia and coagulopathy, use of antifibrinolytics, and intraoperative cell salvage. Avoidance of non-steroidal anti-inflammatory drugs and starch-containing solutions is recommended given the potential for platelet dysfunction.
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Randomized Controlled Trial
Differential role of nitric oxide in the psychedelic symptoms induced by racemic ketamine and esketamine in human volunteers.
Animal studies suggest that N-methyl-d-aspartate receptor (NMDAR) hypofunction and subsequent decline in intracellular nitric oxide (NO) are responsible for development of ketamine-induced psychedelic symptoms. To examine this mechanism in humans, we administered the NO donor sodium nitroprusside during infusion of racemic ketamine (RS-ketamine), containing equal amounts of S(+)- and R(-)-ketamine isomers, or esketamine, containing just the S(+)-isomer. ⋯ NTR 5359.
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Atomised intranasal dexmedetomidine administration is an attractive option when sedation is required for paediatric diagnostic procedures, as vascular access is not required. The risk of haemodynamic instability caused by dexmedetomidine necessitates better understanding of its pharmacokinetics in young children. To date, intranasal dexmedetomidine pharmacokinetics has only been studied in adults. ⋯ Mean arterial plasma concentrations of dexmedetomidine in infants and toddlers approached 100 pg ml-1, the low end reported for sedative efficacy, within 20 min of an atomised intranasal administration of 1 μg kg-1. Doubling the dose to 2 μg kg-1 reached this plasma concentration within 10 min and achieved almost twice the peak concentration. Peak plasma concentrations with both doses were reached within 47 min of intranasal administration, with an overall bioavailability of 84%.