British journal of anaesthesia最新文献

Background: We investigated the intraneural spread of injected fluid in brachial plexus nerve roots, examining the potential for intrafascicular spread and identifying influencing factors.

Methods: Twelve deliberate ultrasound-guided intraneural injections were performed at the ventral rami of the brachial plexus nerve roots at their exits from the neuroforamina in six fresh, unembalmed, cryopreserved human cadavers. A 22-G, 30-degree bevel echogenic regional anaesthesia needle was used. Each injection contained 1 ml of heparinised erythrocytes as a marker. Nerve swelling observed on ultrasound images confirmed intraneural injection.

Results: Intraneural spread was observed in 12 ventral rami of the six brachial plexi: C5 (1), C6 (3), C7 (5), C8 (2), and T1 (1). Among these, intrafascicular spread was detected in eight cases, six in monofascicular roots and two in bifascicular roots, though none in roots with three or more fascicles. The fascicle diameters in these cases (2.1-3.8 mm) were at least twice the diameter of the needle orifice, measured at 0.9 mm, which was entirely inside the fascicles. In the four cases with intraneural but without intrafascicular spread, the fascicle diameters were about two times the diameter of the needle orifice in three instances, but the entire needle orifice was not always inside a fascicle.

Conclusions: In contrast with multifascicular peripheral nerves, intrafascicular spread was possible after deliberate intraneural injections near the neuroforaminal canal exit of the brachial plexus nerve roots in several monofascicular or bifascicular ventral rami if the fascicle diameter was more than twice the needle opening length and the entire opening was inside the fascicle.

Neuromuscular blocking agents are a common cause of perioperative hypersensitivity. The sensitivity and specificity of skin tests and in vitro tests in this context have not been determined conclusively, which poses a barrier to accurate diagnosis. Use of challenge testing represents a promising development in this field and a key tool in confirming tolerance to an alternate neuromuscular blocking agent for use in future anaesthesia. However, its use is currently limited to specialised centres, and a standardised approach to testing has not yet been established. This article summarises the role of challenge testing to neuromuscular blocking agents and highlights the advantages and disadvantages of the different approaches.

Background: Point-of-care testing devices to measure haemoglobin (Hgb) frequently inform transfusion decision-making in surgery. This study aimed to examine their accuracy in surgery, focusing on Hgb concentrations of 60-100 g L^-1, a range with higher potential for transfusion.

Methods: This was a prospective diagnostic cohort study focused on method comparison, conducted at two academic hospitals. Consecutive patients undergoing noncardiac surgery and requiring point-of-care Hgb measurements were eligible. Hgb concentrations from arterial and central venous blood samples were measured concurrently using three devices and compared with laboratory Hgb. The primary outcome was individual pairwise comparisons between point-of-care and laboratory Hgb values; agreement was determined based on a threshold of within 4 g L^-1. The primary analysis consisted of computing limits of agreement.

Results: A total of 1735 intraoperative blood samples were collected (1139 participants); 680 samples had a laboratory Hgb <100 g L^-1. The limits of agreement among those with Hgb <100 g L^-1 were -9.5 to 8.0 g L^-1 for HemoCue®, -16.2 to 11.5 g L^-1 for i-STAT®, and -14.7 to 40.5 g L^-1 for Rad-67®. HemoCue was associated with a 5.8% incidence of potentially clinically significant transfusion error, whereas i-STAT and Rad-67 were associated with 25.3% and 28.2%, respectively. HemoCue yielded Hgb measurements within 10 g L^-1 in 98% of intraoperative blood samples.

Conclusions: No point-of-care Hgb device demonstrated limits of agreement that were smaller than the agreement difference of 4 g L^-1. Despite this, HemoCue can be safely used to inform transfusion decisions in surgery, given its error probability of <4% in transfusion scenarios.

Viscoelastic testing permits targeted correction of coagulopathy in bleeding patients. As new generations of viscoelastic testing platforms become available, research exploring similarities and differences with older devices can provide insight for institutions seeking to use the newer technologies. Care must be taken to ensure such studies are designed to produce clinically meaningful guidance for adapting existing treatment algorithms to accommodate the latest viscoelastic testing technology.