Inhalation of nitrous oxide expands epidural air bubbles

Robert Petty, Rom Stevens*, Scott Erickson, John Lucio, Tzu Cheg Kao

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Background and Objectives. Epidural air bubbles are known to persist for more than 24 hours after injection. Nitrous oxide may cause expansion of these bubbles. Methods. Nine dogs were anesthetized. Ten mL air and 9 mL of iophendylate were injected into the lumbar epidural space. Control animals (n = 3) breathed halothane in 100% oxygen. Experimental animals (n = 6) breathed halothane in 70/30 nitrous oxide/oxygen. Lateral radiographs were taken before and just after injection, and again 3 hours after breathing either 70% nitrous oxide or 100% oxygen. Epidural space pressure was monitored and recorded during these 3 hours. Results. In all experimental animals, an increase in bubble size was observed. In the control animals, bubble size either remained the same or decreased. Epidural space pressure did not change in any animal. Conclusions, Inhalation of nitrous oxide results in expansion of epidural air bubbles. This may cause displacement of epidural local anesthetics if large volumes of air are present in the epidural space.

Original languageEnglish
Pages (from-to)144-148
Number of pages5
JournalRegional Anesthesia
Issue number2
StatePublished - 1996
Externally publishedYes


  • air bubbles
  • anesthetic technique
  • epidural
  • inhaled anesthesia
  • loss-of- resistance technique
  • nitrous oxide


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