In 2022, the WHO conditionally recommended the use of treatment decision algorithms (TDAs) for treatment decision-making in children

Within the Decide-TB project (PACT ID: PACTR202407866544155, 23 July 2024), we aim to generate an individual-participant dataset (IPD) from prospective TB diagnostic accuracy cohorts (RaPaed-TB, UMOYA and two cohorts from TB-Speed). Using the IPD, we aim to: (1) assess the diagnostic accuracy of published TDAs using a set of consensus case definitions produced by the National Institute of Health as reference standard (confirmed and unconfirmed vs unlikely TB); (2) evaluate the added value of novel tools (including biomarkers and artificial intelligence-interpreted radiology) in the existing TDAs; (3) generate an artificial population, modelling the target population of children eligible for WHO-endorsed TDAs presenting at primary and secondary healthcare levels and assess the diagnostic accuracy of published TDAs and (4) identify clinical predictors of radiological disease severity in children from the study population of children with presumptive TB.

This study will externally validate the first data-driven WHO TDAs in a large, well-characterised and diverse paediatric IPD derived from four large paediatric cohorts of children investigated for TB. The study has received ethical clearance for sharing secondary deidentified data from the ethics committees of the parent studies (RaPaed-TB, UMOYA and TB Speed) and as the aims of this study were part of the parent studies’ protocols, a separate approval was not necessary. Study findings will be published in peer-reviewed journals and disseminated at local, regional and international scientific meetings and conferences. This database will serve as a catalyst for the assessment of the inclusion of novel tools and the generation of an artificial population to simulate the impact of novel diagnostic pathways for TB in children at lower levels of healthcare. TDAs have the potential to close the diagnostic gap in childhood TB. Further finetuning of the currently available algorithms will facilitate this and improve access to care.

Suicidal thoughts and behaviours are linked to a wide range of mental health conditions. New interest in the psychiatric benefits of nitrous oxide (N₂O) has only recently emerged. The broad pharmacological effects of N₂O are thought to be due in large part to N-methyl-d-aspartate antagonism and opioid effects. The purpose of this study protocol is to test whether inhalational N₂O exerts rapid antisuicidal effects as a transdiagnostic treatment for suicidal ideation.

This is the protocol of a single-centre pilot study of N₂O inhalation in 85 psychiatric inpatients. The initial 45-min double-blind, randomised, placebo-controlled inhalation session either consists of 50% N₂O and 50% oxygen (‘active treatment’) or 50% oxygen plus air. The primary outcome is the change in Beck Scale for Suicidal Ideation scores between the day before and the day after inhalation. A second inhalation containing N₂O will be administered 1 week after the first inhalation to ensure that all study participants receive the active treatment at least once. For the mechanism of action and prediction, a nested biomarker substudy will employ multimodal techniques, including analysis of hair and blood samples and electroencephalography.

This study was approved by the local ethics committee (‘Kantonale Ethikkommission—Kanton Zürich’) and by the Swiss Agency for Therapeutic Products (Swissmedic). Study results will be disseminated primarily by peer-reviewed scientific journals and also by conference presentations, patient and public events and social media.

ClinicalTrials.gov ID NCT06636357.