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Summary: High‐flow nasal oxygen is increasingly used for oxygenation during apnoea. Extending apnoea duration using this technique has mainly been investigated during minor laryngeal surgery, but it is unclear how long it can be administered for before it should be discontinued due to acidosis. We aimed to describe the dynamics of arterial blood gases during apnoeic oxygenation with high‐flow nasal oxygen with jaw thrust only, to explore the limits of this technique. We included adult orthopaedic patients scheduled for general anaesthesia. After pre‐oxygenation, anaesthesia with neuromuscular blockade was induced and high‐flow nasal oxygen (70 l.min−1) was continued with jaw thrust as the only means of airway management, with monitoring of vital signs and arterial blood gas sampling every 5 minutes. Apnoeic oxygenation with high‐flow nasal oxygen was discontinued when arterial carbon dioxide tension (PaCO2) exceeded 12 kPa or pH fell to 7.15. This technique was used in 35 patients and median (IQR [range]) apnoea time was 25 (20–30 [20–45]) min and was discontinued in all patients when pH fell to 7.15. The mean (SD) PaCO2 increase was 0.25 (0.06) kPa.min−1 but it varied substantially (range 0.13–0.35 kPa.min−1). Mean (SD) arterial oxygen tension was 48.6 (11.8) kPa when high‐flow nasal oxygen was stopped. Patients with apnoea time > 25 minutes were significantly older (p = 0.025). We conclude that apnoeic oxygenation with high‐flow nasal oxygen resulted in a significant respiratory acidosis that varies substantially on the individual level, but oxygenation was maintained. [ABSTRACT FROM AUTHOR]

Objectives: Most international STI guidelines recommend Chlamydia trachomatis anorectal testing in women after self-reported sexual exposure or symptoms in women. However, it has been shown that the prevalence of anorectal C. trachomatis is as high (7%-17 %) in women who do not report anorectal intercourse (AI) as in women who do. This study assessed the correlation between the genital and anorectal C. trachomatis load in concurrently infected women for increased microbiological insight.Methods: A convenience sample of 105 women with a concurrent (genital and anorectal) C. trachomatis infection was included from the STI clinic in South Limburg, the Netherlands. Women provided self-collected vaginal and anorectal swabs. The C. trachomatis load was quantified with qPCR and the human cell load was assessed to ensure sample adequacy. Genital and anorectal C. trachomatis loads were divided into tertiles for comparison. The χ2 test and linear regression were used to compare genital and anorectal C. trachomatis loads and identify determinants associated with load.Results: The overall median C. trachomatis load was higher in genital (median 5.3 log10C. trachomatis/ml) than anorectal samples (median 3.4, p ≤ 0.001), but both loads were within the same range. The genital and anal load categories were not related within one woman (p = 0.99), both in women with and without AI. The anorectal C. trachomatis load was in the same or higher load category than the genital load in 56% of women without AI, and 79% of women with AI.Conclusions: Although no cut-off for clinical relevance is known, an anorectal C. trachomatis load in the same or higher load category than the genital C. trachomatis load is likely to be clinically relevant. Other measurements should also be taken into account, such as leucocytes or bacterial viability to distinguish infection from contamination or exposure. [ABSTRACT FROM AUTHOR]