Anaesthesia
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Randomized Controlled Trial
Microcirculation and haemodynamics after infraclavicular brachial plexus block using adrenaline as an adjuvant to lidocaine: a randomised, double-blind, crossover study in healthy volunteers.
We evaluated the effect of adrenaline on human skin microcirculation (nutritive and sub-papillary) and systemic cardiovascular variables after it was added to lidocaine in infraclavicular brachial plexus blocks. Twelve healthy, non-smoking male volunteers were included, each attending two study sessions 2 weeks apart, and they were studied using a crossover design. In both sessions, they received an ultrasound-guided infraclavicular brachial plexus block in the non-dominant arm with 0.4 ml.kg-1 lidocaine, 15 mg.ml-1 with or without adrenaline 5 μg.ml-1. ⋯ No significant changes were found in the systemic cardiovascular variables with or without adrenaline. We conclude that lidocaine infraclavicular brachial plexus blocks caused an increase in skin sub-papillary blood flow. The addition of adrenaline produced stronger and longer lasting blocks, but decreased the nutritive blood flow.
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Randomized Controlled Trial Comparative Study
Comparison of the analgesic effect of an adductor canal block using a new suture-method catheter vs. standard perineural catheter vs. single-injection: a randomised, blinded, controlled study.
We performed a randomised, blinded, controlled study with adult patients scheduled for primary total knee arthroplasty under spinal anaesthesia. The aim was to investigate the analgesic effects of adductor canal block using catheter-based repeated boluses, either through a new suture-method catheter or a standard perineural catheter, compared with a single-injection technique. All patients received an adductor canal block after surgery with an initial bolus of 20 ml ropivacaine 0.75%, followed by 20 ml of ropivacaine 0.2% every 8 h in the standard and suture-method catheter groups, and sham boluses for the single-injection group. ⋯ On postoperative day 2, there were no differences between catheter groups, but muscle strength and ambulation were improved compared with the single-injection group. We conclude that providing repeated boluses via a catheter did not decrease opioid consumption or pain compared with a single injection, but improved muscle strength and ambulation on postoperative day 2. The two types of catheters were similar.
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Modern mechanical ventilator technologies broadly consist of digitally-controlled electronic devices and analogue systems driven by compressed gas sources. Drawbacks such as high cost, complex maintenance and the need for cumbersome sources of compressed driving gas hinder adoption in pre-hospital and low-resource environments. We describe the evaluation and testing of a simple, low-cost alternative ventilator that uses a novel pressure-sensing approach and control algorithm. ⋯ During intermittent positive-pressure ventilation to the test-lung, the prototype system showed acceptable pressure waveform parameters: all simulated circuit leaks ≥ 6 mm2 in size were detected; compliance changes were detected between 10 ml.cmH2 O-1 , 20 ml.cmH2 O-1 and 50 ml.cmH2 O-1 ; and resistance changes were detected across the available simulated range. These results show this prototype technology has the potential to provide safe emergency ventilation without the use of any complex digital sensors or software while its construction and design enables significant reductions in cost and complexity. The study suggests further work is now justified in progressing the technology to clinical trials.