Anaesthesia
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Editorial Comment
Carbon dioxide clearance during apnoea with high-flow nasal oxygen: epiphenomenon or a failure to THRIVE?
Toner notes the rapid adoption of high-flow nasal oxygen for apnoeic oxygenation, particularly in the context of competing alternatives that have not enjoyed the same popularity.
Specifically, it is highlighted that there is a lack of high-quality RCTs confirming the ability of Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE) to acceptably clear CO2 with prolonged periods of apnoea. RCT results are awaited.
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Randomized Controlled Trial
The impact of fluid optimisation before induction of anaesthesia on hypotension after induction.
Intra-operative hypotension is a known predictor of adverse events and poor outcomes following major surgery. Hypotension often occurs on induction of anaesthesia, typically attributed to hypovolaemia and the haemodynamic effects of anaesthetic agents. We assessed the efficacy of fluid optimisation for reducing the incidence of hypotension on induction of anaesthesia. ⋯ Forty-two (30%) goal-directed fluid therapy patients underwent fluid optimisation after finding an intravascular fluid deficit via passive leg raise testing; 106 (75%) goal-directed fluid therapy and 112 (79%) standard fluid therapy patients met criteria for haemodynamic instability. There was no significant difference in the incidence of haemodynamic instability between the goal-directed fluid therapy and standard fluid therapy groups using absolute mean arterial pressure drop below 55 mmHg (p = 0.58) or using pre-surgical testing or pre-surgical mean arterial pressure values as baseline (p = 0.21, p = 0.89, respectively); however, the difference in the incidence of haemodynamic instability was significant using the operating theatre baseline mean arterial pressure (p = 0.004). We conclude that fluid optimisation before induction of general anaesthesia did not significantly impact haemodynamic instability.
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Randomized Controlled Trial Comparative Study
Determining the effective pre-oxygenation interval in obstetric patients using high-flow nasal oxygen and standard flow rate facemask: a biased-coin up-down sequential allocation trial.
Using biased-coin sequential allocation, we sought to determine the effective time interval in 90% of healthy parturients to achieve a target endpoint end-tidal oxygen of ≥ 90% using standard flow rate facemask and high-flow nasal oxygen. Eighty healthy parturients were randomly assigned to standard facemask (n = 40) or high-flow nasal oxygen (n = 40) groups; half of the parturients in the high-flow nasal oxygen group also used a simple no-flow facemask to minimise air entrainment. The effective time interval for 90% of parturients to achieve the target endpoint for standard facemask was 3.6 min (95%CI 3.3-6.7 min), but could not be estimated for the high-flow nasal oxygen groups with or without an additional simple facemask, as eight minutes was insufficient to achieve the target endpoint for 55% and 92% of parturients, respectively. ⋯ After four minutes, the target endpoint was reached by 100% in the standard facemask, 80% in the high-flow nasal oxygen with simple facemask and 67% in the high-flow nasal oxygen groups. Beyond four minutes, there was no improvement in pre-oxygenation success using high-flow nasal oxygen. In conclusion, under the conditions of our study, the effective time interval for 90% of parturients to achieve an end-tidal oxygen ≥ 90% for standard flow rate facemask was estimated to be 3.6 min, but could not be estimated for high-flow nasal oxygen groups even after eight minutes.
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We conducted a survey and semi-structured qualitative interviews to investigate current anaesthetic practice for arteriovenous fistula formation surgery in the UK. Responses were received from 39 out of 59 vascular centres where arteriovenous access surgery is performed, a response rate of 66%. Thirty-five centres reported routine use of brachial plexus blocks, but variation in anaesthetic skill-mix and practice were observed. ⋯ The use of regional anaesthesia for arteriovenous fistula formation in the UK is varied and influenced by a multitude of factors. Despite the availability of anaesthetists capable of performing regional blocks, there are other limiting factors that influence the routine use of this technique. The study also highlighted the perceived need for a large multicentre, randomised controlled trial to provide an evidence base to inform current practice.
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Which journals cite work published in anaesthetic journals is of potential interest to authors, editors and publishers. We analysed citations made in 2017-2018 for articles, reviews, editorials and letters published by 12 anaesthetic journals in 2016, using the Web of Science™ citation index platform. We analysed 12,544 citations made for 3518 items. ⋯ The median (IQR [range]) proportion of citations made by the same journal that published the items (i.e. 'self-citations') was 15% (11-17% [5-32%]). There were 1305/1932 (68%) citations made by North American journals for items published in North American journals and 1712/2063 (83%) citations made by European journals for items published in European journals, p < 0.0001. Our analysis may inform authors, editors and publishers where to submit work, what editorial policy to pursue and what journal strategy to follow, respectively.