Anaesthesia
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Review
Postoperative analgesia for shoulder surgery: a critical appraisal and review of current techniques.
Shoulder surgery is well recognised as having the potential to cause severe postoperative pain. The aim of this review is to assess critically the evidence relating to the effectiveness of regional anaesthesia techniques commonly used for postoperative analgesia following shoulder surgery. Subacromial/intra-articular local anaesthetic infiltration appears to perform only marginally better than placebo, and because the technique has been associated with catastrophic chondrolysis, it can no longer be recommended. ⋯ Suprascapular nerve block reduces postoperative pain and opioid consumption following arthroscopic surgery, but provides inferior analgesia compared with single injection interscalene block. Continuous interscalene block incorporating a basal local anaesthetic infusion and patient controlled boluses is the most effective analgesic technique following both major and minor shoulder surgery. However, interscalene nerve block is an invasive procedure with potentially serious complications and should therefore only be performed by practitioners with appropriate experience.
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Randomized Controlled Trial Comparative Study
A comparison of the Airway Scope and McCoy laryngoscope in patients with simulated restricted neck mobility.
We compared the efficacy of the Airway Scope and McCoy laryngoscope as intubation tools with the neck stabilised by a rigid cervical collar. After induction of anaesthesia and neck stabilisation, 100 patients were randomly assigned to tracheal intubation with an Airway Scope or McCoy laryngoscope. ⋯ However, the mean (SD) time required for successful intubation was shorter with the Airway Scope (30 (7) s) than with the McCoy laryngoscope (40 (14) s; p < 0.0001). The incidences of intubation complications were similar, but oesophageal intubation (in six cases) occurred only with McCoy laryngoscope.
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Randomized Controlled Trial
Effect of midazolam on memory: a study of process dissociation procedure and functional magnetic resonance imaging.
To assess the effects of midazolam on explicit and implicit memories, 12 volunteers were randomly divided into the two groups: one with an Observer's Assessment of Alertness/Sedation score of 3 (mild sedation) and one with a score of 1 (deep sedation). Blood oxygen-level-dependent functional magnetic resonance imaging was measured before and during an auditory stimulus, then with midazolam sedation, and then during a second auditory stimulus with continuous midazolam sedation. After 4 h, explicit and implicit memories were assessed. ⋯ However, a deep level of midazolam sedation depressed activation of the superior temporal gyrus by auditory stimulus. We conclude that midazolam does not abolish implicit memory at a mild sedation level, but can abolish both explicit and implicit memories at a deep sedation level. The superior temporal gyrus may be one of the target areas.
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Randomized Controlled Trial
Effect-site concentration of remifentanil attenuating surgical stress index responses to intubation of the trachea.
Surgical Stress Index has been proposed for assessment of surgical stress and analgesia. It is a numeric index based on the normalised pulse beat interval and photoplethysmographic pulse wave amplitude. We determined the effect-site concentration of remifentanil for attenuation of Surgical Stress Index responses to intubation of the trachea. ⋯ Mean (SD) effect-site concentrations of remifentanil attenuating responses in 50% of patients were 2.13 (0.25) ng x ml(-1) and 3.05 (0.27) ng x ml(-1) in deep and normal groups, respectively (p = 0.034). From probit analysis, EC(50) and EC(95) of remifentanil (95% CI) were 2.34 (1.97-2.71) ng x ml(-1) and 3.19 (2.69-3.69) ng x ml(-1) in deep group and 3.17 (2.67-3.67) ng x ml(-1) and 3.79 (3.21-4.37) ng x ml(-1) in the normal group, respectively. The values from probit analysis and up-and-down method did not differ significantly.
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Comparative Study
Comparison of mechanomyography and acceleromyography for the assessment of rocuronium induced neuromuscular block in myotonic dystrophy type 1.
We measured acceleromyography and mechanomyography simultaneously with monitoring of rocuronium-induced neuromuscular block in four patients with myotonic dystrophy type 1. Furthermore, we compared neuromuscular block measures from these patients with those from normal controls from previous studies. In myotonic dystrophy type 1 patients, the dose-response curve obtained with acceleromyography was steeper and right-shifted compared with that obtained using mechanomyography. ⋯ In both patients and normal controls, neuromuscular block recovered faster with acceleromyography. However, in one patient with severe muscle wasting, recovery of neuromuscular block was prolonged. We conclude that mechanomyography and acceleromyography cannot be used interchangeably to monitor neuromuscular block in myotonic dystrophy type 1 patients.