II. Background: Hydrogen Sulfide
- Hydrogen Sulfide is a Sulfur-Based Toxic Gas
- Flammable, colorless gas
- Poisonous
- Malodorous (rotten egg smell)
- Air Pollutant
- Manufacturing reagent
- Chemical manufacturing
- Petroleum processing
- Sewage processing
- Metallurgy
- Agriculture
- Analytical Chemistry
- Intentional Poisoning (Suicide attempt)
- Acid (e.g. toilet bowl cleaner) combined with sulfur-containing molecule (e.g. Pesticides, fungicide, lime sulfur)
- Results in release of Hydrogen Sulfide (H2S)
III. Pathophysiology: Hydrogen Sulfide Toxicity
- Toxicity
- Concentrations <100 ppm will be detectable as a rotten egg smell
- Prolonged exposure at lower levels may result in loss of olfactory detection
- Concentrations >100 ppm result in Loss of Smell by olfactory paralysis (no rotten egg smell detected)
- Concentrations >500 ppm are rapidly lethal by inhalation
IV. History
- Sudden collapse in an enclosed work area such as a sewer (esp. if rotten egg smell was reported)
V. Signs
- Ocular ("gas eye")
- Conjunctivitis
- Photophobia
- Lacrimation
- Cardiopulmonary
- Gastrointestinal
- Neurologic
VI. Labs
- See Poisoning
- Sulfide concentrations
- Blood sulfide concentration
- Blood and urine thiosulfate concentration
-
Venous Blood Gas (or Arterial Blood Gas)
- Metabolic Acidosis (due to Lactic Acidosis)
VIII. Management
- Immediately remove patient from Hydrogen Sulfide source
- Patients may start to improve in open air once removed from source
- ABC Management
- Respiratory Management
- Nonrebreather 100% oxygen
- Noninvasive Positive Pressure Ventilation (e.g. BiPap) or Mechanical Ventilation with PEEP
- Hypotension management
- Sulfide Antidotes
- Sodium Nitrite 3% 0.2 ml per kg (children) up to 10 ml or 300 mg in adults IV over 2-4 min
- Hydroxycobalamin (cyanokit) 2.8 ml/kg or 70 mg/kg (children) up to 200 ml or 5 g in adults over 15 min
- May reduce Hydrogen Sulfide Toxicity
- Also indicated if co-exposure to Cyanide is suspected
- Cobinamide (experimental)
- Disposition
- Admit all patients with respiratory of neurologic signs or symptoms
- Patients with only mild mucosal irritation (e.g. Conjunctivitis) may be discharged home
IX. Complications
- Neurologic and psychiatric sequelae may be longstanding
X. Resources
- Hydrogen Sulfide (OSHA)
- Hydrogen Sulfide Toxicity (Stat Pearls)
XI. References
- Swadron and Nordt (2022) EM:Rap 22(6): 5-7
- Tomaszewski (2017) Crit Dec Emerg Med 31(10): 24