Anaesthesia
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Randomized Controlled Trial
Therapeutic doses of neostigmine, depolarising neuromuscular blockade and muscle weakness in awake volunteers: a double-blind, placebo-controlled, randomised volunteer study.
Neostigmine reverses non-depolarising neuromuscular blockade, but may cause muscle weakness when administered after full recovery of neuromuscular function. We hypothesised that neostigmine in therapeutic doses impairs muscle strength and respiratory function in awake healthy volunteers. Twenty-one volunteers were randomised to receive two doses of either intravenous (i.v.) neostigmine 2.5 mg with glycopyrrolate 450 μg (neostigmine group, n = 14) or normal saline 0.9% (placebo group, n = 7). ⋯ The second dose of neostigmine with glycopyrrolate further decreased grip strength mean (SD) -41 (23) % vs. +1.0 (15) %, p = 0.0004; single twitch height -25 (15) % vs. -2.5 (6.6) %, p = 0.0030; predicted forced expiratory volume in 1 s -23 (24) % vs. -0.7 (4.4) %, p = 0.0063; and predicted forced vital capacity, -27.1 (22.0) % vs. -0.66 (3.9) %, p = 0.0010. Train-of-four ratio remained unchanged (p = 0.22). In healthy volunteers, therapeutic doses of neostigmine induced significant and dose-dependent muscle weakness, demonstrated by a decrease in maximum voluntary hand grip strength and a restrictive spirometry pattern secondary to depolarising neuromuscular blockade.
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Randomized Controlled Trial
Effects of depth of neuromuscular block on surgical conditions during laparoscopic colorectal surgery: a randomised controlled trial.
There have been few objective evaluations of the effects of deep neuromuscular blockade on intra-operative conditions. In this prospective randomised controlled study, we evaluated the effects of deep neuromuscular block on surgical conditions during laparoscopic colorectal surgery. Patients were randomly allocated using a computer-generated randomisation code to either moderate (train-of-four count 1-2 maintained and antagonised with neostigmine) or deep (post-tetanic count 1-2 maintained and reversed with sugammadex) levels of neuromuscular blockade. ⋯ In total, we recruited 70 patients of whom 64 (32 in each group) were analysed. Increases in intra-abdominal pressure (14/32 vs. 6/32; p = 0.031), intra-operative restoration of spontaneous breathing (16/32 vs. 2/32; p < 0.001) and request for additional neuromuscular blockade (21/32 vs. 8/32; p = 0.001) were more frequent in the moderate compared with the deep group. In patients undergoing elective laparoscopic colorectal surgery, deep neuromuscular blockade provided better surgical conditions than moderate neuromuscular blockade, as measured by a reduction in the incidence of intra-abdominal pressure alarms.
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Controlled Clinical Trial
The ability of a real-time injection pressure monitoring system to discriminate between perineural and intraneural injection of the sciatic nerve in fresh cadavers.
Injection pressure monitoring provides valuable information to prevent intraneural injections and possibly consequent nerve damage during peripheral nerve block. However, the measurement of injection pressure along the injection line is inaccurate as it is influenced by several variables. The aim of this study was to test a new system for precise injection pressure monitoring at the needle tip in a cadaveric model. ⋯ Two perineural and two intraneural injections were excluded from analysis, since the operator could not confirm the exact needle-tip location. Mean (SD) peak injection pressure was significantly lower for perineural compared with intraneural injections (14 (6) kPa vs. 131 (56) kPa; p < 0.001). This study shows that this system is a reliable method to accurately monitor injection pressure at the needle tip, allowing for discrimination between perineural and intraneural injections of the sciatic nerve in fresh cadavers.
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Practice Guideline
Association of Anaesthetists guidelines: cell salvage for peri-operative blood conservation 2018.
The use of cell salvage is recommended when it can be expected to reduce the likelihood of allogeneic (donor) red cell transfusion and/or severe postoperative anaemia. We support and encourage a continued increase in the appropriate use of peri-operative cell salvage and we recommend that it should be available for immediate use 24 h a day in any hospital undertaking surgery where blood loss is a recognised potential complication (other than minor/day case procedures).
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Viscoelastic assays such as TEG® and ROTEM® are increasingly used to guide transfusion of blood products. The EXTEM assay maximum clot firmness (MCF) is a ROTEM measure available after 25-29 min used to guide early decisions. EXTEM A10, the clot firmness at 10 min, is an accepted early surrogate, but investigators differ on whether A5, the clot firmness at 5 min, is acceptable. ⋯ Using a value of A5 < 29 mm, for a pragmatic positive predictive value of 20%, gave a sensitivity of 67%, specificity 95% and negative predictive value 99%. Whether aiming for a high sensitivity or a strong predictive value, A5 was non-inferior to A10 and actually missed fewer cases needing massive transfusion. A5 has similar utility to both A10 and maximum clot firmness as an early measure of clot firmness, and a low A5 value is strongly predictive of the need for massive transfusion.