Ease and comfort of pre-oxygenation with high-flow nasal oxygen cannulae vs. facemask: a randomised controlled trial.

The Difficult Airway Society recommends that all patients should be pre-oxygenated before the induction of general anaesthesia, but this may not always be easy or comfortable and anaesthesia may often be induced without full pre-oxygenation. We tested the hypothesis that high-flow nasal oxygen cannulae would be easier and more comfortable than facemasks for pre-oxygenation. We randomly allocated 199 patients undergoing elective surgery aged ≥ 10 years to pre-oxygenation using either high-flow nasal oxygen or facemask. Ease and comfort were assessed by anaesthetists and patients on 10-cm visual analogue scale and six-point smiley face scale, respectively. Secondary endpoints included end-tidal oxygen fraction after securing a definitive airway and time to secure an airway. A mean difference (95%CI) between groups in ratings of -0.76 (-1.25 to -0.27) cm for ease of use (p = 0.003) and -0.45 (-0.75 to -0.13) points for comfort (p = 0.006), both favoured high-flow nasal oxygen. A mean difference (95%CI) between groups in end-tidal oxygen fraction of 3.89% (2.41-5.37%) after securing a definitive airway also favoured high-flow nasal oxygen (p < 0.001). There was no significant difference between groups in the number of patients with hypoxaemia (Sp O2 < 90%) or severe hypoxaemia (Sp O2 < 85%) lasting ≥ 1 min or ≥ 2 min; in the proportion of patients with an end-tidal oxygen fraction < 87% in the first 5 min after tracheal intubation (52.2% vs. 58.9% in facemask and high-flow nasal oxygen groups, respectively; p = 0.31); or in time taken to secure an airway (11.6 vs. 12.2 min in facemask and high-flow nasal oxygen groups, respectively; p = 0.65). In conclusion, we found pre-oxygenation with high-flow nasal oxygen to be easier for anaesthetists and more comfortable for patients than pre-oxygenation with a facemask, with no clinically relevant differences in end-tidal oxygen fraction after securing a definitive airway or time to secure an airway. The differences in ease and comfort were modest.

The effect of antibiotic timing on culture yield in paediatric osteoarticular infection.

PURPOSE: To assess the influence of antibiotic timing on surgical culture yield in paediatric patients with haematogenous osteoarticular infection. METHODS: All patients aged 0 to 15 years admitted to a National Children's Hospital with the diagnosis of acute, haematogenous, osteoarticular infection (osteomyelitis and/or septic arthritis) between June 1997 and December 2016 were retrospectively analyzed. Only patients with positive blood cultures undergoing surgery for culture and debridement were included. Patients were allocated into pre-treatment and post-treatment groups, according to whether they received antibiotics before or after surgical cultures were obtained. Outcomes measured included baseline variables, treatment characteristics and surgical culture yield. RESULTS: A total of 131 patients were included; 107 patients in the pre-treatment group and 24 patients in the post-treatment group. There was no significant difference with respect to patient age (p = 0.870), white blood cell count (p = 0.197), ethnicity (p = 0.203) or infection multi-focality (p = 0.883) between the two groups.The administration of systemic antibiotics prior to obtaining surgical cultures had no clinically significant effect on surgical culture yield (rate of positive surgical cultures, 85% (pre-treatment) versus 54.2% (post-treatment); p = 0.002). Within the pre-treatment group, there was no significant difference in duration of pre-surgical antibiotic treatment between patients who had positive or negative surgical cultures (mean duration, 45.9 hours (positive cultures) versus 47.9 hours (negative cultures); p = 0.743). CONCLUSION: In paediatric patients with acute, haematogenous, osteoarticular infection, antibiotic administration before surgery does not decrease surgical culture yield. Our results suggest that paediatric patients presenting with suspected osteoarticular infection should receive appropriate systemic antibiotics promptly after blood cultures are obtained. LEVEL OF EVIDENCE: Level III - retrospective case-control study.

Gene expression confirms a potentially receptive endometrium identified by histology in fertile women.

BACKGROUND: To use contemporary biochemical markers to characterize mRNA/gene expression in the potentially fertile secretory endometrium to confirm its identification based on histological characteristics in order to develop a clinically applicable test. METHODS: Nine, fertile, cycling Caucasian women were sampled from one IVF clinic. Endometrial samples were collected from them in two to four menstrual cycles at 2 and 7 days post first significant rise in blood LH. Separate endometrial glands and stroma populations were obtained by laser microdissection. Linear polymerase chain reaction amplified mRNAs which were hybridized to both Affymetrix U133 Plus2 and Agilent 4 × 44K microarrays followed by gene set analysis. Four histopathologists reviewed the sample set using the same histological criteria to date and characterize the non-receptive and potentially receptive samples. RESULTS: mRNA expression of microdissected glands and stroma provided molecular signatures that characterized the two specific phases of the cycle with distinct clustering patterns. Cell proliferation and five other associated biological pathways were significantly down-regulated when the endometrium is considered potentially receptive accompanied by an increase in secreted glycoproteins mRNAs in the potentially receptive glands. Reported histological findings identified the presence of one histological feature characteristic of each phase: glandular mitoses indicated a non-receptive endometrium, whereas a potentially receptive endometrium was distinguished by supranuclear vacuolation. CONCLUSIONS: This study defined a transcriptome characteristic of active cell proliferation in the non-receptive samples with a marked overall down-regulation of this pathway in potentially receptive samples-suggesting a transitional state associated with receptivity but not implantation. However, microarrays involve expensive, specialized testing and require significant post-data analysis. Sampling according to endocrinological and molecular prediction improved the consistency of histological assessment and allowed reliable histological markers of glandular mitosis in the non-receptive phase and supranuclear vacuolation of the potentially receptive endometrium to be identified. Thus, histology can provide an affordable, clinically applicable test in the context of reproduction.