Mechanisms of harm

• Cardiotoxicity: volatile hydrocarbons sensitize myocardium to catecholamines, causing ventricular arrhythmias and “sudden sniffing death.”
• Hypoxia: displacement of oxygen, airway compromise, aspiration and respiratory depression can cause hypoxic injury.
• Toxic metabolites: nitrites cause methemoglobinemia; chronic nitrous oxide causes B12 inactivation and neuropathy.
• Direct pulmonary injury: aspiration pneumonitis after inhaling hydrocarbon liquids or vomiting while intoxicated.

Typical clinical features

• Early: dizziness, lightheadedness, euphoria, slurred speech, incoordination, nystagmus.
• Progression: confusion, stupor, depressed consciousness, cyanosis, seizures, ataxia, arrhythmias.
• Specific signs: chemical smell on breath, stained hands/face, rags or containers nearby; chocolate‑brown blood suggests methemoglobinemia.

Immediate assessment

1. Primary survey (A, B, C): secure airway, give high‑flow oxygen, support ventilation.
2. Continuous cardiac monitoring and pulse oximetry; obtain 12‑lead ECG immediately.
3. Rapid history: substance identity (if known), time of exposure, co‑ingestants, loss of consciousness, and prior medical history (esp. CVD, seizures, pregnancy).
4. Baseline tests: ABG, CBC, electrolytes, renal and liver function, methemoglobin level if nitrite exposure suspected, blood glucose, and consider tox screen.

Emergency management

• Oxygen: administer high‑flow oxygen for hypoxia and to reduce risk of arrhythmia.
• Cardiac care: monitor for arrhythmias; treat ventricular arrhythmia per ACLS. Avoid adrenaline when possible if hydrocarbons suspected because of arrhythmia sensitisation — consult cardiology/TOX if needed.
• Methylene blue: indicated for symptomatic methemoglobinemia (usually >20–30% or with significant symptoms) — dose 1–2 mg/kg IV; avoid in G6PD deficiency without specialist input.
• Supportive care: airway protection, IV fluids, treat seizures with benzodiazepines, and manage aspiration pneumonitis with oxygen, bronchodilators and antibiotics if secondary infection suspected.
• Nitrous oxide specifics: in acute cases treat symptoms; in chronic users consider assessing B12 and give supplementation (intramuscular or high‑dose oral) and neurology referral for neuropathy.

Disposition & monitoring

• Admit for observation if there was loss of consciousness, arrhythmia, hypoxia, seizures, or significant comorbidity.
• Serial ECGs and observation for delayed arrhythmias; repeat methemoglobin and ABG as clinically indicated.
• Consider ICU admission for unstable cardiac or respiratory status.

Follow‑up care

• Evaluate for neurocognitive or neurological sequelae — memory, gait, neuropathy; refer to neurology/rehab if deficits persist.
• Offer brief interventions, motivational interviewing and referral to addiction services for ongoing inhalant misuse.
• Screen for social needs (housing, family support) and coordinate with community services, especially for adolescents.

Key takeaways

• Inhalant intoxication can be fatal — prioritise ABCs, oxygen and cardiac monitoring.
• Treat methemoglobinemia with methylene blue when indicated and consider B12 assessment for chronic nitrous oxide users.
• Arrange follow‑up for addiction treatment, social support and neurological assessment where needed.