Observational studyEmergency medicine journal : EMJ2025
Development and evaluation of a novel prehospital antidote service providing methylthioninium chloride (methylene blue) for sodium nitrite poisoning.
Observational study in Emergency medicine journal : EMJ, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
1 citing paper in PubMed.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundSodium nitrite has become established as a method of self-harm and suicide. Toxicity occurs primarily through the formation of methaemoglobin (MetHb). In response to a coroner request, West Midlands Ambulance Service developed a prehospital methylthioninium chloride (methylene blue) capability within the specialist Hazardous Area Response Team (HART) to treat methaemoglobinaemia. A service evaluation was planned to understand the impact.
methodsA retrospective observational series of patients, during a planned evaluation period from 1 July 2020 to 1 July 2024. All patients receiving a HART response for suspected sodium nitrite poisoning were included. A Patient Group Direction (PGD) for the treatment of methaemoglobinaemia by paramedics was produced, allowing treatment with intravenous methylthioninium chloride 1-2 mg/kg in specific circumstances. MetHb levels were assessed using handheld pulse CO-Oximeters.
resultsNine patients were attended for suspected sodium nitrite toxicity and three were administered prehospital methylthioninium chloride under PGD indications. In addition, one patient had no evidence of toxicity, four had conditions unequivocally associated with death and one was in cardiac arrest. The patient in cardiac arrest received sodium nitrite in hospital from the HART team under verbal direction from medical staff but did not survive. Serial CO-Oximeter readings for two of the three patients who received methylthioninium chloride indicated a decrease in MetHb levels and all three survived. Consumable costs associated with the new capability were minimal. Potential improvements to the service were identified, including changes to PGD indications.
conclusionThe limited number of cases seen in the evaluation period suggests that restricting the prehospital provision of methylthioninium chloride to specialist teams is proportionate, and it appears feasible for specialist paramedics to deliver prehospital methylthioninium chloride under PGD indications. However, prehospital use of methylthioninium chloride for the treatment of methaemoglobinaemia currently lacks sufficient evidence to support widespread adoption without further evaluation.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.