Anaesthesia
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Randomized Controlled Trial Comparative Study
A randomised controlled trial comparing continuous supraclavicular and interscalene brachial plexus blockade for open rotator cuff surgery.
Continuous interscalene block is an approved modality for postoperative pain control, but it may cause hemidiaphragmatic paresis. In this study we aimed to determine whether continuous supraclavicular block would provide postoperative analgesia comparable to that of continuous interscalene block and reduce the incidence of hemidiaphragmatic paresis. Patients scheduled for open rotator cuff repair were randomly allocated to receive continuous interscalene (n = 38) or supraclavicular block (n = 37). ⋯ Postoperative mean (SD) pain scores at 24 h were similar in the supraclavicular and interscalene groups (2.57 (1.71) vs 2.84 (1.75) respectively; p = 0.478). The incidence of complete or partial hemidiaphragmatic paresis was lower in the supraclavicular group at 1 h after admission to the postanaesthetic care unit and 24 h after the surgery [25 (68%) vs 38 (100%); p = 0.001 and 14 (38%) vs 27 (71%) respectively; p = 0.008]. Continuous supraclavicular block provided comparable analgesia compared with interscalene block with a reduced incidence of complete or partial hemidiaphragmatic paresis for 24 h following surgery.
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Impaired platelet function is a major risk factor for peri-operative bleeding and transfusion. This prospective, observational study enrolled 101 consecutive patients undergoing elective cardiac surgery with cardiopulmonary bypass. Platelet function was assessed by two whole blood impedance aggregometers (ROTEM(®) platelet and Multiplate(®) ), using three different activators (arachidonic acid, adenosine diphosphate and thrombin receptor-activating peptide-6), at three peri-operative time points (before anaesthesia, after aortic declamping and 5-10 min after protamine administration). ⋯ Patients with a chest tube drainage exceeding the 75th percentile of the entire study population, during the first 24 postoperative hours, were characterised to have excessive bleeding. Both devices provided similar predictability for postoperative chest tube drainage and red blood cell transfusion requirements. The latter was associated with the degree of platelet inhibition and the number of pathways inhibited determined respective cut-off values.
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Recognising frailty during pre-operative assessment is important. Frail patients experience higher mortality rates and are less likely to return to baseline functional status following the physiological insult of surgery. We evaluated the association between an initial clinical impression of frailty and all-cause mortality in 392 patients attending our vascular pre-operative assessment clinic. ⋯ Using Cox regression, adjusted for age, sex, revised cardiac risk index and surgery (yes/no), the hazard ratio for mortality for frail vs. not-frail was 2.14 (95% CI 1.51-3.05). The time to 20% mortality was 16 months in the frail group and 33 months in the not-frail group. The initial clinical impression is a useful screening tool to identify frail patients in pre-operative assessment.
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Observational Study
Lumbar neuraxial anatomical changes throughout pregnancy: a longitudinal study using serial ultrasound scans.
This observational study was designed to investigate the anatomical changes of the lumbar spine over the course of pregnancy using serial ultrasound scans. We performed paramedian scans on 58 women at the L2-3, L3-4 and L4-5 levels; these were done at four periods of 11+0-13+6, 19+0-23+0, 28+0-32+0 and 38+0-40+0 weeks gestation. At each intervertebral level, the length of the interlaminar space, length of the visible intervertebral posterior dura and depth of the posterior dura mater from the skin were measured. ⋯ The other spinal measurements were not affected by gestation. These findings indicate that the L2-3 level is the most appropriate puncture site for epidural anaesthesia in pregnant women. Our results ought to be embraced as a departure point towards developing neuraxial insertion techniques guided or aided by ultrasound.
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Randomized Controlled Trial
The minimum effective concentration (MEC90 ) of ropivacaine for ultrasound-guided supraclavicular brachial plexus block.
The aim of this study was to determine the minimum effective concentration of ropivacaine for ultrasound-guided supraclavicular brachial plexus block. Fifty-one patients undergoing arm surgery received double-injection ultrasound-guided supraclavicular block using ropivacaine 40 ml. The concentration of ropivacaine administered to each patient started at 0.225% and then depended on the response of the previous one, based on a biased coin design up-and-down sequential method. ⋯ In the case of a successful block, the next patient was randomised to the same concentration or a concentration 0.025% w/v less. Success was defined as complete sensory blockade of the brachial plexus 30 min after the block together with pain-free surgery. The minimum effective ropivacaine concentration in 90% of subjects was 0.257% w/v (95% CI 0.241-0.280%).