Anaesthesia
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Randomized Controlled Trial
A randomised double-blind trial of phenylephrine and metaraminol infusions for prevention of hypotension during spinal and combined spinal-epidural anaesthesia for elective caesarean section.
Metaraminol infusion for hypotension prevention during spinal anaesthesia for Caesarean section is non-inferior to phenylephrine infusion.
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Randomized Controlled Trial
A prospective, randomised trial of pre-oxygenation strategies available in the pre-hospital environment.
Pre-oxygenation before tracheal intubation aims to increase safe apnoea duration by denitrogenation of the functional residual capacity of the lungs, and increasing oxygen stores at the onset of apnoea. Pre-oxygenation options in the pre-hospital environment are limited due to oxygen availability and equipment portability. The aim of this study was to evaluate the effectiveness of strategies available in this setting. ⋯ Pre-oxygenation efficacy with the non-rebreather mask was significantly worse than with either the bag-valve-mask (p < 0.001) or ventilator (p < 0.001). No significant difference in ease of breathing was identified between the bag-valve-mask and ventilator, but both were perceived as being significantly more difficult to breathe through than the non-rebreather mask. We conclude that, in healthy volunteers, the effectiveness of pre-oxygenation by bag-valve-mask and portable ventilator was superior to pre-oxygenation with a non-rebreather mask, although the non-rebreather mask was easier to breathe through than the other pre-oxygenation devices.
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Randomized Controlled Trial Comparative Study
A randomised crossover simulation study comparing the impact of chemical, biological, radiological or nuclear substance personal protection equipment on the performance of advanced life support interventions.
Recent incidents involving chemical, biological, radiological and nuclear substances have stressed the importance of sufficient personal protection equipment for medical first-responders. Modern lightweight, battery-independent, suit ensembles may prove superior to the current protective suit used in the UK. This study compared the powered respiratory protective suit (PRPS ensemble) with a lightweight suit consisting of a SARATOGA® Multipurpose CBRN Protective Coverall Polyprotect 12 in conjunction with the Avon C50 Respirator/Avon CBRNF12CE filter canister and butyl rubber protective gloves (Polyprotect 12 ensemble). ⋯ Total mean (SD) completion time for the five interventions was significantly longer for the PRPS compared with the Polyprotect 12 ensemble (204 (53) s vs. 149 (36) s, respectively; p < 0.0001). Participants rated mobility, noise, heat, vision, dexterity and speech intelligibility significantly better in the Polyprotect 12 ensemble compared with the PRPS ensemble. The combination of a lightweight Polyprotect 12 suit and an Avon C50 air-purifying respirator is preferable to the powered respiratory protective suit during simulated emergency life support, due to a combination of shorter task completion times and improved mobility, communication and dexterity.
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Randomized Controlled Trial
Sevoflurane-induced isoelectric EEG and burst suppression: differential and antagonistic effect of added nitrous oxide.
The objective of this study was to investigate whether nitrous oxide influenced the ED50 of sevoflurane for induction of isoelectric electroencephalogram (ED50isoelectric ) differently from its influence on the ED50 of sevoflurane for electroencephalogram burst suppression (ED50burst ). In a prospective, randomised, double-blind, parallel group, up-down sequential allocation study, 77 ASA physical status 1 and 2 patients received sevoflurane induction and, after tracheal intubation, were randomly allocated to receive sevoflurane with either 40% oxygen in air (control group) or 60% nitrous oxide in oxygen mixture (nitrous group). The ED50isoelectric in the two groups was determined using Dixon's up and down method, starting at 2.5% with 0.2% step size of end-tidal sevoflurane. ⋯ The values for ED50burst were 3.05 (95%CI, 2.66-3.90)% and 3.02 (95%CI, 3.00-3.05)% in nitrous group and control group, respectively (p = 0.52). The addition of 60% nitrous oxide increases ED50isoelectric , but not the ED50burst of sevoflurane. Neither result indicates an additive effect of anaesthetic agents, as might be expected, and possible reasons for this are discussed.