Anaesthesia
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The objective of this study was to estimate the minimal effective anaesthetic concentrations of ropivacaine required to block the femoral nerve in 90% of patients. Forty-five patients who had knee surgery received ultrasound-guided femoral nerve block using 15 ml ropivacaine. The ropivacaine concentration given to a patient relied on the efficacy of the block in the previous patient, using the biased-coin design up-down sequential method. ⋯ Successful block was defined as complete sensory and motor block before surgery together with pain-free surgery. The minimal effective ropivacaine concentration was estimated to be 0.167% w/v (95% CI 0.14-0.184%). Perineural injection of 15 ml ropivacaine 0.167% w/v under ultrasound guidance can provide successful femoral nerve block in 90% of patients.
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Randomized Controlled Trial Comparative Study
A randomised crossover comparison of mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation by surf lifeguards in a manikin.
Thirty surf lifeguards (mean (SD) age: 25.1 (4.8) years; 21 male, 9 female) were randomly assigned to perform 2 × 3 min of cardiopulmonary resuscitation on a manikin using mouth-to-face-shield ventilation (AMBU LifeKey) and mouth-to-pocket-mask ventilation (Laerdal Pocket Mask). Interruptions in chest compressions, effective ventilation (visible chest rise) ratio, tidal volume and inspiratory time were recorded. Interruptions in chest compressions per cycle were increased with mouth-to-face-shield ventilation (mean (SD) 8.6 (1.7) s) compared with mouth-to-pocket-mask ventilation (6.9 (1.2) s, p < 0.0001). ⋯ Tidal volume was lower using mouth-to-face-shield ventilation (mean (SD) 0.36 (0.20) l) compared with mouth-to-pocket-mask ventilation (0.45 (0.20) l, p = 0.006). No differences in inspiratory times were observed between mouth-to-face-shield ventilation and mouth-to-pocket-mask ventilation. In conclusion, mouth-to-face-shield ventilation increases interruptions in chest compressions, reduces the proportion of effective ventilations and decreases delivered tidal volumes compared with mouth-to-pocket-mask ventilation.