Anaesthesia
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing the effects of propofol with isoflurane in patients with diastolic dysfunction undergoing coronary artery bypass graft surgery.
There is a strong association between pre-operative diastolic dysfunction and difficulty in weaning from cardiopulmonary bypass. We compared the effects of propofol and isoflurane on left ventricular diastolic function in patients with pre-existing diastolic dysfunction undergoing coronary artery bypass grafting. We randomly allocated 60 patients to receive either propofol or isoflurane anaesthesia, and assessed left ventricular diastolic function using transoesophageal echocardiography. ⋯ Both propofol and isoflurane improved left ventricular diastolic function as evidenced by significant increases in E/A ratios, and significant decreases in deceleration time and isovolumetric relaxation time; the improvement was greater in the isoflurane group (between groups, p = 0.001 for both E/A ratio and deceleration time at T1 and T2 and p = 0.006 for isovolumetric relaxation time at both T1 and T2 ). Furthermore, Em/Am ratio, S, D and S/D ratios were significantly better in the isoflurane group. The administration of isoflurane during cardiac surgery improves diastolic function comparatively more than propofol.
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Randomized Controlled Trial Comparative Study
A prospective randomised study of a rigid video-stylet vs. conventional lightwand intubation in cervical spine-immobilised patients.
Compared with a lightwand which is used blind, Optiscope™ , a rigid video-stylet, can provide direct imaging of airway structures, potentially offering improved conditions in cervical spine-immobilised patients. We randomly assigned 168 patients who required cervical immobilisation during tracheal intubation to use of the Optiscope or the lightwand. ⋯ The incidence of postoperative airway complications was similar in the two groups. The devices were equivalent with respect to initial intubation success rate but the Optiscope yielded slightly longer intubating times.
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Controlled Clinical Trial
High-flow humidified nasal oxygenation vs. standard face mask oxygenation.
Ten healthy volunteers received oxygen for 1 min, 2 min and 3 min at 10 l.min-1 via a face mask, or humidified oxygen at 60 l.min-1 via nasal prongs (OptiflowTM ) with the mouth closed and with the mouth open. The mean (SD) end-tidal oxygen partial pressure after 3 min face mask and Optiflow oxygenation, with mouth closed and open, were: 88.5 (6.2) kPa; 85.6 (6.4) kPa and 48.7 (26.4) kPa, respectively, p = 0.001. The equivalent mean (SD) transcutaneous oxygen partial pressures were: 34.6 (5.4) kPa; 36.4 (6.5) kPa and 25.5 (15.7) kPa, respectively, p = 0.03. High-flow humidified nasal oxygenation for 3 min with the mouth closed was as effective as 3 min face mask oxygenation.
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Observational Study
Construct validity of a novel assessment tool for ultrasound-guided axillary brachial plexus block.
The purpose of this study was to examine the construct validity and reliability of a novel metrics-based assessment tool, previously developed for ultrasound-guided axillary brachial plexus block. Five expert and eight novice anaesthetists performed a total of 18 ultrasound-guided axillary brachial plexus blocks on the same number of patients. A trained investigator video-taped procedures according to a pre-defined protocol. ⋯ Compared with novices, experts completed more steps (mean 41.0 vs. 33.1, p = 0.001), had fewer procedural errors (2.8 vs. 7.9, p < 0.0001), had fewer critical errors (0.8 vs. 1.3, p = 0.030), and fewer total errors (3.5 vs. 9.1, p < 0.0001). The mean inter-rater reliability for scoring of experts' performance was 0.91, for novices' performance was 0.84, and for all performance combined (n = 18) was 0.88. This assessment tool is valid, and discriminates reliably between expert and novice performance for placement of ultrasound-guided axillary brachial plexus blocks.
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing two popliteal nerve catheter tip positions for postoperative analgesia after day-case hallux valgus repair.
We compared the effect of two different positions of a sciatic nerve catheter within the popliteal fossa on local anaesthetic consumption and postoperative analgesia in patients undergoing day-case hallux valgus repair. Eighty-four patients were randomly allocated to receive a sciatic nerve catheter either between the tibial and peroneal components (sciatic group) or medial to the tibial nerve (tibial group). ⋯ Insensate limb occurred in 14 patients in the sciatic group versus one patient in the tibial group (p < 0.001), while foot drop was reported by six patients in the sciatic group and none in the tibial group (p = 0.012). Sciatic nerve catheter placement medial to the tibial nerve may be a superior analgesic technique for day-case foot surgery.