Anesthesiology
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Clinical Trial
The corrugator supercilii, not the orbicularis oculi, reflects rocuronium neuromuscular blockade at the laryngeal adductor muscles.
Some studies suggest that the orbicularis oculi is resistant to neuromuscular blocking drugs and behaves like laryngeal muscles. Others report little or no difference between the orbicularis oculi and the adductor pollicis. These discrepancies could be related to the exact site of recording. The purpose of this study was to compare two monitoring sites around the eye with the adductor pollicis and the laryngeal adductor muscles. ⋯ Muscles around the eye vary in their response to rocuronium. The response of the superciliary arch (corrugator supercilii) reflects blockade of laryngeal adductor muscles. However, the eyelid (orbicularis oculi) and thumb (adductor pollicis) have similar sensitivities.
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The authors wished to determine whether a simulator-based evaluation technique assessing clinical performance could demonstrate construct validity and determine the subjects' perception of realism of the evaluation process. ⋯ The simulation-based evaluation method was able to discriminate between practice categories, demonstrating construct validity. Subjects rated the realism of the test scenario highly, suggesting that familiarity or comfort with the simulation environment had little or no effect on performance.
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Clinical Trial
Failure of autologous fresh frozen plasma to reduce blood loss and transfusion requirements in coronary artery bypass surgery.
Previous studies failed to demonstrate any benefit from prophylaxis with fresh frozen plasma (FFP) after cardiopulmonary bypass (CPB). The results, however, were limited by either retrospective study design or use of FFP in subtherapeutic doses (2-3 units). The authors evaluated whether a therapeutic dose (15 ml/kg) of FFP reduces blood loss and transfusion requirements in elective coronary artery bypass surgery. The risks of multiple allogeneic blood donor exposure were circumvented by using autologous plasma. ⋯ The prophylactic administration of a therapeutic dose (15 ml/kg) of autologous FFP after CPB failed to reduce blood loss and transfusion requirements in patients undergoing uncomplicated, elective, primary coronary artery bypass surgery.
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Studies show that the sedative and analgesic effects of alpha2 adrenergic agonists decrease over time, which is a form of synaptic plasticity referred to as tolerance. Because both the N-methyl-D-aspartate (NMDA) receptor complex and nitric oxide synthase are pivotal for some forms of synaptic plasticity, their role in tolerance to the hypnotic and analgesic effects of alpha2 agonists was investigated. ⋯ The underlying processes responsible for the development of tolerance to the hypnotic and analgesic actions of systemically administered alpha2 agonists were different, with only the sedative tolerance involving the NMDA receptor and nitric oxide synthase system.
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Inhaled nitric oxide (INO) is thought to cause selective pulmonary vasodilation of ventilated areas. The authors previously showed that INO to a hyperoxic lung increases the perfusion to this lung by redistribution of blood flow, but only if the opposite lung is hypoxic, indicating a more complex mechanism of action for NO. The authors hypothesized that regional hypoxia increases NO production and that INO to hyperoxic lung regions (HL) can inhibit this production by distant effect. ⋯ Inhaled nitric oxide downregulates endogenous NO production in other, predominantly hypoxic, lung regions. This distant effect is blood-mediated and causes vasoconstriction in lung regions that do not receive INO.