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Summary Background Non-invasive ventilation has never been compared with high-flow oxygen to determine whether it reduces the risk of severe hypoxaemia during intubation. We aimed to determine if preoxygenation with non-invasive ventilation was more efficient than high-flow oxygen in reducing the risk of severe hypoxaemia during intubation. Methods The FLORALI-2 multicentre, open-label trial was done in 28 intensive care units in France. Adult patients undergoing tracheal intubation for acute hypoxaemic respiratory failure (a partial pressure of arterial oxygen [PaO 2 ] to fraction of inspired oxygen [FiO 2 ] ratio of ≤300 mm Hg) were randomly assigned (1:1; block size, four participants) to non-invasive ventilation or high-flow oxygen during preoxygenation, with stratification by PaO 2 /FiO 2 ratio (≤200 mm Hg vs >200 mm Hg). Key exclusion criteria were intubation for cardiac arrest, altered consciousness (defined as a Glasgow coma score of less than eight points), other contraindications to non-invasive ventilation (recent laryngeal, oesophageal, or gastric surgery, and substantial facial fractures), pulse oximetry not available, pregnant or breastfeeding women, and refusal to participate. The primary outcome was the occurrence of severe hypoxaemia (pulse oximetry <80%) during the procedure, assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov , number NCT02668458. Findings Between April 15, 2016, and Jan 8, 2017, 2079 patients were intubated in the 28 participating units, and 322 were enrolled. We excluded five patients with no recorded data, two who withdrew consent or were under legal protection, one who was not intubated, and one who had a cardiac arrest. Of the 313 patients included in the intention-to-treat analysis, 142 were assigned to non-invasive ventilation and 171 to high-flow oxygen therapy. Severe hypoxaemia occurred in 33 (23%) of 142 patients after preoxygenation with non-invasive ventilation and 47 (27%) of 171 with high-flow oxygen (absolute difference −4·2%, 95% CI −13·7 to 5·5; p=0·39). In the 242 patients with moderate-to-severe hypoxaemia (PaO 2 /FiO 2 ≤200 mm Hg), severe hypoxaemia occurred less frequently after preoxygenation with non-invasive ventilation than with high-flow oxygen (28 [24%] of 117 patients vs 44 [35%] of 125; adjusted odds ratio 0·56, 0·32 to 0·99, p=0·0459). Serious adverse events did not differ between treatment groups, with the most common immediate complications being systolic arterial hypotension (70 [49%] patients in the non-invasive ventilation group vs 86 [50%] patients in the high-flow oxygen group) and chest infiltrate on x-ray (28 [20%] vs 33 [19%]), and the most common late complications being death at day 28 (53 [37%] vs 58 [34%]) and ventilator-associated pneumonia during ICU stay (31 [22%] vs 35 [20%]). Interpretation In patients with acute hypoxaemic respiratory failure, preoxygenation with non-invasive ventilation or high-flow oxygen therapy did not change the risk of severe hypoxaemia. Future research should explore the effect of preoxygenation method in patients with moderate-to-severe hypoxaemia at baseline. Funding French Ministry of Health. [ABSTRACT FROM AUTHOR]

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Copyright of Archives of Cardiovascular Diseases is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent studies have suggested that visualization of gamma-H2AX nuclear foci can be used to estimate exposure to very low doses of ionizing radiation. Although this approach is widely used for various purposes, its suitability for individual human biodosimetry has not yet been assessed. We therefore conducted such an assessment with the help of available software for observing and automatically scoring gamma-H2AX foci. The presence of gamma-H2AX foci was evaluated in human peripheral blood lymphocytes exposed ex vivo to gamma rays in a dose range of 0.02 to 2 Gy. We analyzed the response of gamma-H2AX to ionizing radiation in relation to dose, time after exposure, and individual variability. We constructed dose-effect calibration curves at 0.5, 8 and 16 h after exposure and evaluated the threshold of detection of the technique. The results show the promise of automatic gamma-H2AX scoring for a reliable assessment of radiation doses in a dose range of 0.6 Gy to 2 Gy up to 16 h after exposure. This gamma-H2AX-based assay may be useful for biodosimetry, especially for triage to distinguish promptly among individuals the ones who have received negligible doses from those with significantly exposures who are in need of immediate medical attention. However, additional in vivo experiments are needed for validation.

The technique of measuring the frequency of dicentric chromosomal aberrations in blood lymphocytes was used to estimate doses in a simulated criticality accident. The simulation consisted of three exposures; approximately 5 Gy with a bare source and 1 and 2 Gy with a lead-shielded source. Three laboratories made separate estimates of the doses. These were made by the iterative method of apportioning the observed dicentric frequencies between the gamma and neutron components, taking account of a given gamma/neutron dose ratio, and referring the separated dicentric frequencies to dose-response calibration curves. An alternative method, based on Bayesian ideas, was employed. This was developed for interpreting dicentric frequencies in situations where the gamma/neutron ratio is uncertain. Both methods gave very similar results. One laboratory produced dose estimates close to the eventual exercise reference doses and the other laboratories estimated slightly higher values. The main reason for the higher values was the calibration relationships for fission neutrons.

The Institute of Radiation Protection and Nuclear Safety (IRSN) organized a biological dosimetry international intercomparison with the purpose of comparing (i) dicentrics yield produced in human lymphocytes; (ii) the gamma and neutron dose estimate according to the corresponding laboratory calibration curve. The experimental reactor SILENE was used with different configurations: bare source 4 Gy, lead shield 1 and 2 Gy and a 60Co source 2 Gy. An increasing variation of dicentric yield per cell was observed between participants when there were more damages in the samples. Doses were derived from the observed dicentric rates according to the dose-effect relationship provided by each laboratory. Differences in dicentric rate values are more important than those in the corresponding dose values. The doses obtained by the participants were found to be in agreement with the given physical dose within 20%. The evaluation of the respective gamma and neutron dose was achieved only by four laboratories, with some small variations among them.

From 1995 to 1996 about 15 people suspected of being overexposed to ionizing radiation were referred to the Institute for Nuclear Safety and Protection in Fontenay-aux-Roses, France, for investigation by chromosome aberration analysis. Biological estimates of accidental overexposure were first obtained by scoring radio-induced unstable structural chromosome aberrations (dicentrics, centric rings, and fragments) in peripheral blood lymphocytes. For dose estimates, the yield of these chromosomal aberrations observed in 500 metaphases was compared with the laboratory dose-response relationship established from human blood irradiated in vitro (gamma-rays, 60Co, 0.5 Gy/min). To extend the possibilities of detecting DNA damage from earlier exposures by visualizing stable chromosome aberrations, chromosome painting by fluorescence in situ hybridization (FISH painting) was developed using a cocktail of three composite whole human chromosome-specific DNA probes (numbers 2, 4, and 12). A laboratory calibration curve for scoring terminal and/or reciprocal translocations was established for the same radiation quality and dose rate as those used for conventional cytogenetics (gamma-rays, 60Co, 0.5 Gy/min). For dosimetry purposes, it was also important to verify whether FISH painting could be applied to each human blood sample assessed for conventional expertise. For each individual, 2000 metaphases were scored for the presence or absence of reciprocal and terminal translocations. We present here a comparison between the results obtained by the two technologies for each of the cases studied separately. We describe their similarities or differences and discuss the suitability of using FISH painting for routine expertise analysis.