Nitrous oxide

Background

• For minimal sedation or anxiolysis
• It may be used as an adjunct with local anesthetics for more painful procedures

Indications

• Older than 4 years and/or weighing greater than 15 kg
• ASA Class 1 or 2
• Sole Nitrous Oxide use examples include:
  • Peripheral or Central IV placement
  • Urinary catheter insertion
  • Intramuscular injections
  • Joint aspiration or injection
  • Lumbar puncture
  • Laceration repair
  • Abscess incision and drainage
  • Nail removal
  • Wound packing or dressing change
  • Foreign body removal
• Nitrous Oxide + opioid or benzodiazepine examples include (smaller dosages should be used initially and titrated PRN)
  • Lumbar puncture
  • Laceration repair
  • Abscess incision and drainage
  • Foreign body removal
  • Simple or minimally displaced fracture reduction

Contraindications

Nitrous accumulates in potential spaces and is potentially problematic when there are recent lung or ocular surgery.

• Caution should be used when combined with benzodiazepines or other sedatives
• Age less than 4 years and/or weight less than 15 kg
• ASA Class 3 or above
• Closed head injury, recent craniotomy, altered level of consciousness or suspicion of elevated intracranial pressure
• Penetrating globe injury or recent eye surgery
• Complex upper respiratory infection (obstructive sinusitis, bullous otitis media)
• Maxillofacial injuries
• Acute asthma, bullous emphysema or pneumonia
• Pneumothorax or chest trauma
• Pulmonary hypertension
• Congenital heart disease
• Bowel obstruction or ileus
• Recent SCUBA diving, barotrauma or decompression illness
• Pregnancy

Procedure

• Pre-sedation establishment of an IV is not required
• General monitoring procedures shall be followed
• Nitrous oxide administration should be limited to 30 minutes
• Administer 100% oxygen for 2-5 minutes after discontinuing nitrous oxide or if nitrous oxide / oxygen administration is interrupted for > 30 seconds

Toxicity

• Asphyxia, if oxygen is not given with the gas
  • Headache
  • Dizziness
  • Confusion
  • Syncope
  • Seizures
• Chronic toxicity results from B12 inactivation
  • Megaloblastic anemia
  • Thrombocytopenia
  • Peripheral Neuropathy

See Also

• Nitrous oxide toxicity