Biomarkers for the diagnosis and monitoring of nitrous oxide intoxication: objectives and methodology of the SFBC Working Group.

The recreational use of nitrous oxide (N2O) is an emerging public health issue. Chronic N2O abuse may result in various clinical symptoms, encompassing neurological, psychiatric and cardiovascular outcomes. Despite the difficulties for the laboratory investigation of N2O intoxication, there is currently no guidelines in France to help both clinicians and biologists use appropriate biomarkers for the diagnosis and monitoring of patients with clinical symptoms potentially related to N2O intoxication. A multi-disciplinary Working Group, carried out under the auspices of the French Society of Clinical Biology (SFBC) and in collaboration with the French Societies of Emergency Medicine (SFMU), Analytical Toxicology (SFTA), Hemostasis and Thrombosis (SFTH), Vitamins and Biofactors (SFVB), and the French Federation of Neurology (FFN), was recently implemented to elaborate practical guidelines. The methodology of the Working Group is based on the critical analysis of the literature, and raising concerns and objectives are grouped into five working packages. The present manuscript primarily aims to expound upon the methodology and objectives of the ongoing SFBC Working Group on N2O.

Performance and Impact on Antibiotic Prescriptions of a Multiplex PCR in a Real-Life Cohort of Critically Ill Patients with Suspected Ventilated Pneumonia: A Retrospective Monocentric Observational Study.

Pulmonary multiplex polymerase chain reaction (m-PCR) allows rapid pathogen detection. We aimed to assess its impact on initial antibiotic prescriptions in ventilated patients with suspected pneumonia. Between November 2020 and March 2022,ventilated patients with suspected pneumonia hospitalized in our ICU who benefited from respiratory sampling simultaneously tested using conventional microbiological methods and m-PCR were included. The proportion of appropriate changes in the initial antibiotic therapy following m-PCR results was assessed. We analyzed 104 clinical samples. Of the 47 negative m-PCR results, 16 (34%) led to an appropriate antibiotic strategy: 8 cessationsand 8 lack of initiation. Of the 57 positive m-PCR results, 51 (89%) resulted in an appropriate antibiotic strategy: 33 initiations, 2 optimizations, and 9 de-escalations. In the multivariate analysis, a positive m-PCR was associated with an appropriate antibiotic change (OR: 96.60; IC95% [9.72; 960.20], p < 0.001). A higher SAPS II score was negatively associated with an appropriate antibiotic change (OR: 0.96; IC95% [0.931; 0.997], p = 0.034). In our cohort, a positive m-PCR allowed for early initiation or adjustment of antibiotic therapy in almost 90% of cases. A negative m-PCR spared antibiotic use in onethird of cases. The impact of m-PCR results was reduced in the most severe patients.

Determining clinical predictors to identify non-specific abdominal pain and the added value of laboratory examinations: A prospective derivation study in a paediatric emergency department.

AIM: To develop a model to discriminate non-specific abdominal pain (NSAP) from organic pain in the paediatric emergency department (PED) and evaluate the added value of laboratory markers. METHODS: Prospective cohort study in an urban French PED including all patients aged ≥4 years with abdominal pain between November 2020 and May 2021. The outcome was the discrimination between NSAP (patients coded to have only "pain" or "constipation") and organic pain (all other diagnoses) using stepwise backward multivariate logistic regression method with bootstrap resampling. RESULTS: The study enrolled 246 patients. Overall, 163 patients (66.2%) had NSAP. Four variables associated with organic pain: pain in the epigastric region (OR 0.48 [0.23-0.99]), worsening pain (0.57 [0.32-0.99]), pain migration (0.42 [0.17-0.99]) and vomiting (0.47 [0.26-0.84]) were integrated in a clinical model. To discriminate NSAP with a probability of 65%, model sensitivity was 71.8% (64.9-78.7), specificity was 53.0% (42.3-63.7), and the Net Benefit (NB) was 15.4%. White Blood Count and C-reactive protein results improved discriminative capacity of the model (AUC 0.708 [0.643-0.773] vs. 0.654 [0.585-0.723], p = 0.01) with a supplementary NB of 12%. Patient follow-up showed 95% diagnostic accuracy. CONCLUSION: This study reveals a four-clinical predictor model with a NB of 15% in predicting NSAP. Validation studies are necessary.

Fatal and near-fatal anaphylaxis: The Allergy-Vigilance® Network data (2002-2020).

BACKGROUND: Having a better understanding of the risk factors of severe anaphylaxis is a crucial challenge for physicians. METHODS: To retrospectively analyse fatal/near-fatal anaphylaxis cases recorded by the Allergy-Vigilance® Network (2002-2020) and evaluate the characteristics associated with survival, age and allergens. RESULTS: Among the 3510 anaphylaxis cases documented in the network, 70 (2%) patients (males: 57%; mean age: 35.4 y) presented grade 4 (Ring-Messmer) anaphylaxis and 25 died (19 food-related); 33% had a history of asthma. The main allergens were food (60%; peanut, 20%; milks, 11%) involved in 25/26 cases in children and in 17/44 (39%) cases in adults. Non-food anaphylaxis was related to drugs/latex (24%; neuromuscular blocking agents, 10%; betalactamins, 6%), Hymenoptera (16%). Three food-related cases (one death) occurred during oral food challenge in children. Patients with a food allergy were younger (22.2 years vs. 55 years, p < .001), had more likely a history of asthma (50% vs. 7%; p < .001), a pre-existing allergy (62% vs. 18%; p < .001) compared with other allergies. A cofactor was identified in 35 cases (50%) but predominantly in adults as opposed to children (64% vs. 27%; p = .01). The patients who died were younger (25.6 vs. 40.8 years; p = .01) than the survivors and mostly presented bronchospasm (56% vs. 29%; p = .05). Gaps in the prevention and management of anaphylaxis were noted in 15 cases (21%). CONCLUSIONS: Severe food anaphylaxis has specific features compared with other causes such as young age, asthma history and exercise. Food is also involved in severe anaphylaxis in adults that should not be underestimated.