Anaesthesia
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Comparative Study Clinical Trial
Observational study comparing non-invasive blood pressure measurement at the arm and ankle during caesarean section.
Upper-arm non-invasive blood pressure measurement during caesarean section can be uncomfortable and unreliable because of movement artefact in the conscious parturient. We aimed to determine whether ankle blood pressure measurement could be used instead in this patient group by comparing concurrent arm and ankle blood pressure measured throughout elective caesarean section under regional anaesthesia in 64 term parturients. ⋯ Although ankle blood pressure measurement is well tolerated and allows greater mobility of the arms than measurement from the arm, the degree of discrepancy between the two sites is unacceptable to allow routine use of ankle blood pressure measurement, especially for systolic arterial pressure. However, ankle blood pressure measurement may be a useful alternative in situations where arm blood pressure measurement is difficult or impossible.
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Randomized Controlled Trial
The effect of the jaw-thrust manoeuvre on the ability to advance a tracheal tube over a bronchoscope during oral fibreoptic intubation.
During fibreoptic intubation, it is often difficult to advance a tracheal tube over the fibreoptic bronchoscope. We performed a prospective randomised study to investigate the effect of the jaw-thrust manoeuvre on the ability to advance a tracheal tube during oral fibreoptic intubation. ⋯ The jaw-thrust group had a higher success rate on the first attempt (70.7% vs 34.1%, p = 0.002), required fewer attempts (median (IQR [range]) 1 (1-2 [1-3]) vs 2 (1-3 [1-4]), p < 0.001), and took less time [6 (4-8 [2-16]) s vs 10 (7-15 [3-40]) s, p < 0.001] for tube advancement compared with the control group. The jaw-thrust manoeuvre facilitates the advancement of a tracheal tube over the bronchoscope during oral fibreoptic intubation.
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Since its introduction in 1965, minimum alveolar concentration (MAC) has served as the standard measure of potency for volatile anaesthetic agents. It is defined as the minimum alveolar concentration of inhaled anaesthetic at which 50% of people do not move in response to a noxious stimulus. ⋯ This review highlights the contributions and limitations of MAC and its derivatives as metrics of anaesthetic potency with respect to particular behavioural outcomes. Recent evidence is presented suggesting that a protocol that alerts anaesthetists whenever MAC falls to < 0.5 or 0.7 has the potential to decrease intra-operative awareness with explicit recall, possibly to a similar extent as does a protocol based on processed electroencephalography-driven alerting.
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Randomized Controlled Trial
The combined effects of midazolam and propofol sedation on muscle power.
We performed a randomised, crossover study to investigate the effects of intravenous sedation on grip strength and bite force. Twenty male volunteers received a bolus intravenous injection of midazolam (0.02 mg.kg(-1)) together with a 30-min propofol infusion designed to achieve an effect-site concentration of 1.0 μg.ml(-1). ⋯ Although bite force gradually returned to baseline following flumazenil administration, it remained increased throughout the experimental period. We conclude that bite force increased during intravenous sedation and that this may have clinical implications.