Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Neuromuscular blocking agents are frequently used in the Intensive Care Unit to facilitate tracheal intubation and the application of continuous paralysis. This review will focus on various conditions of the critically ill patient such as multi-organ dysfunction, acid-base and electrolyte imbalance, prolonged immobility, multiple drug interactions and specific disease/injury processes that may affect the pharmacokinetic and pharmacodynamic behaviour of muscle relaxants. As such, due to the complex nature of the critically ill patients, the effects of neuromuscular blocking agents are unpredictable. Therefore, guidelines regarding their administration and the methodology and requirement for continuous bedside monitoring of neuromuscular function will be presented.
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The reduction of arterial blood pressure produced by propofol may be, in part, attributable to impaired baroreflex integrity. The purpose of this study was to investigate arterial baroreflex sensitivity during and after continuous propofol infusion. In urethane anaesthetized rabbits, left renal sympathetic nerves were exposed and placed on a bipolar silver electrode to record renal sympathetic nerve activity (RSNA). ⋯ The baroreflex sensitivity was also evaluated by calculating the ratio of maximum increase of RSNA or HR to SNP-induced maximum decrease of MAP (delta RSNA/delta MAP, delta HR/delta MAP). Despite the same decreases or increases in MAP, RSNA was attenuated after 15 and 30 min of propofol infusion in both groups compared with control (P < 0.05). Decreased delta RSNA/delta MAP gradually returned to the control level 60 min after discontinuation of propofol in Group 1.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Continuous infusions of atracurium and vecuronium, compared with intermittent boluses of pancuronium: dose requirements and reversal.
This study was designed to determine the effect of prolonged infusion on the ease of reversal of atracurium and vecuronium, and whether factors which potentiate the block delayed reversal. In phase one, 40 patients were randomized (double blind) to determine the steady state conditions for atracurium and vecuronium. Fourteen atracurium patients and 17 vecuronium patients were evaluable. ⋯ The addition of an inhalation agent to atracurium reduced the infusion rate by 2.01 +/- 0.28 micrograms.kg-1 x min-1 (P = 0.0001) for each increase in MAC. The mean reversal times for atracurium with three different anaesthetics and for vecuronium were not different. Reversal of pancuronium blockade, from less profound twitch depression (86.4 vs 95%) took twice as long as for atracurium and vecuronium for which the following predictors were identified: age, weight, duration of infusion, level of blockade, and type of anaesthetic, using a stepwise regression model.(ABSTRACT TRUNCATED AT 250 WORDS)
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The purpose of this review is to emphasise the ineffectiveness of traditional analgesic therapy in paediatric patients after surgery, to examine the sensation of pain in infants and children, and to describe the use of intravenous opioids for postoperative analgesia. The management of acute postoperative pain in the paediatric surgical population has been poor. This is despite the knowledge that infants and children have sufficient neurological development at birth to sense pain, and that the same hormonal and metabolic responses to nociceptive stimuli that occur in adult also occur in the neonate. ⋯ Two of these, continuous intravenous opioid infusion and patient-controlled analgesia, have proved to be very successful. Children older than six months can receive either modality safely with regular monitoring by qualified nursing staff. Infants younger than six months receiving continuous opioid infusions should be monitored in high-dependency units.