Hygiene Atlas

Atlas · Plate VIII · Pharmacology and Local Anesthesia · 12

Nitrous oxide sedation

Nitrous oxide gives anxiolysis and mild analgesia while the patient stays conscious with protective reflexes. Its low blood solubility brings onset and recovery within minutes. Machines always deliver at least 30% oxygen; titrate in small steps, then give 100% oxygen for 3-5 minutes at the end to prevent diffusion hypoxia. Scavenging protects staff, and nausea or sweating signals oversedation.

High-yield facts · 10

  1. Nitrous oxide (N2O) is a weak anesthetic that gives anxiolysis and mild analgesia; the patient stays conscious with protective reflexes.S62S63
  2. Blood/gas partition coefficient is about 0.47, so onset and recovery are fast (about 3-5 min).S63
  3. Minimum alveolar concentration (MAC) is about 104%, so N2O cannot cause general anesthesia alone at normal pressure.S63
  4. Machines are fail-safe: they deliver at least 30% oxygen (no more than 70% N2O).S62
  5. Titrate in steps of about 5-10% N2O; most patients are comfortable at about 30-50%.S62
  6. Give 100% oxygen for at least 3-5 minutes at the end to prevent diffusion hypoxia.S62S63
  7. Tank colors (US): N2O is blue; oxygen is green.S62
  8. Use a scavenging system (about 45 L/min) to protect staff; NIOSH REL is 25 ppm time-weighted during administration.S61
  9. Relative contraindications: first trimester pregnancy, COPD with CO2 retention, recent middle ear or eye surgery (gas bubbles), bowel obstruction, pneumothorax, B12 deficiency, substance use recovery, severe psychiatric illness.S62S63
  10. Early signs of oversedation: nausea, sweating, giggling, refusal to keep the mask on, sleepiness.S62

Facts are written in our own words; each tag links to its source. Values marked "sources vary" differ between references, so check the one your program uses.