Treatment of Natural Gas Inhalation
Immediately remove the patient from the exposure source and administer 100% oxygen via high-flow mask or mechanical ventilation if needed, as the primary treatment is supportive care focused on maintaining adequate oxygenation and airway patency. 1, 2
Immediate Airway and Breathing Management
Assess for airway compromise and intubate early if indicated. Consider intubation if any of the following are present 2:
- Respiratory distress or stridor
- Hypoventilation or use of accessory respiratory muscles
- Blistering or edema of the oropharynx
- Deep burns to the face or neck (if thermal injury present)
- Altered mental status with inability to protect airway
Administer 100% oxygen immediately to all patients with suspected natural gas inhalation while awaiting diagnostic confirmation 1, 3, 2. This is critical because:
- Natural gas exposure can cause asphyxiation through oxygen displacement 4, 5
- Concomitant carbon monoxide (CO) poisoning may be present if combustion occurred 1, 3
- Oxygen accelerates elimination of carboxyhemoglobin, reducing its half-life from 320 minutes on room air to 74 minutes on 100% oxygen 1
Diagnostic Evaluation
Obtain carboxyhemoglobin (COHb) levels if there is any possibility of CO exposure from combustion 1, 3. However, recognize that COHb levels correlate poorly with symptoms and may be normal if several hours have elapsed since exposure 1.
Assess for metabolic acidosis and elevated lactate, particularly if exposure occurred in a fire environment, as this may indicate cyanide poisoning requiring specific treatment with hydroxocobalamin 1, 3.
Perform fiberoptic bronchoscopy if upper airway injury is suspected, as this is the only definitive method to recognize or exclude upper respiratory tract obstruction 3.
Monitor pulmonary function, as methane gas inhalation can cause acute pneumonitis with restrictive ventilatory defects 4.
Hyperbaric Oxygen Therapy Considerations
Consider HBOT for severe CO poisoning if combustion was involved. Indications include 1:
- Loss of consciousness during or after exposure
- Neurological deficits
- Ischemic cardiac changes
- Significant metabolic acidosis
- COHb levels >25%
- Pregnancy with any symptoms of CO poisoning
HBOT at 3.0 atmospheres absolute reduces COHb elimination half-life to approximately 20 minutes and may prevent delayed neurological sequelae 1.
Supportive Care
Provide mechanical ventilation if respiratory failure develops, using lung-protective strategies to avoid ventilator-induced lung injury 2. The lung injury from methane gas exposure can manifest as acute pneumonitis but typically resolves spontaneously 4.
Treat bronchospasm if present with nebulized beta-agonists (salbutamol 5 mg or terbutaline 10 mg) driven by oxygen at 6-8 L/min 6.
Monitor for progressive respiratory insufficiency as lower respiratory tract injury may develop over time, manifesting as dyspnea, wheezing, hypoxemia, and reduced pulmonary function 3.
Special Considerations and Pitfalls
Do not delay oxygen therapy while awaiting laboratory confirmation—treat based on clinical suspicion 1, 2.
Ensure the exposure source is identified and eliminated before discharge to prevent re-exposure 1.
Screen for coingestions in cases of intentional exposure, as toxicology screening may reveal other substances in up to 44% of intentional poisoning cases 1.
Arrange follow-up evaluation 1-2 months after exposure to assess for delayed neurological sequelae, including memory disturbance, depression, anxiety, and motor dysfunction 1.
Recognize that natural gas itself (primarily methane) causes toxicity through asphyxiation rather than direct chemical toxicity, distinguishing it from other toxic gas exposures 4, 5. Most patients recover spontaneously with supportive care and oxygen therapy 4.