Laparoscopy explosion hazards with nitrous oxide.
BACKGROUND
During laparoscopic surgery utilizing carbon dioxide as the insufflating agent, nitrous oxide will diffuse into the peritoneal cavity if it is used as part of the anesthetic. Bowel perforation and the subsequent release of volatile bowel gas could create a explosion hazard.


METHODS
Two related studies were undertaken. The first quantified the transfer of nitrous oxide, over time, in 19 female patients undergoing laparoscopy. The second established the lower limits of flammability of a range of concentrations of methane and hydrogen diluted with nitrogen (simulated bowel gas) in a range of concentrations of nitrous oxide diluted with carbon dioxide (simulated peritoneal gas).


RESULTS
The mean concentrations of N2O at 10, 20, and 30 min from the time of insufflation were 19.9 +/- 4.8%, 30.3 +/- 6.8%, and 36.1 +/- 6.9%, respectively. The maximum reported concentrations of methane and hydrogen in bowel gas are 56% and 69%, respectively. The concentration of nitrous oxide necessary to support combustion of 56% methane is approximately 47%. By contrast, the concentration of nitrous oxide needed to support combustion of 69% hydrogen is approximately 29%.


CONCLUSIONS
The authors have shown that it is possible for nitrous oxide to reach concentrations in the peritoneal cavity that can support combustion of bowel gas.
Neuman
G G
GG
Department of Anesthesiology, St. Vincent's Hospital and Medical Center of New York, New York 10011.
Sidebotham
G
G
Negoianu
E
E
Bernstein
J
J
Kopman
A F
AF
Hicks
R G
RG
West
S T
ST
Haring
L
L
D000328:Adult; D002245:Carbon Dioxide / Q000737:chemistry*; D005260:Female; D005740:Gases / Q000737:chemistry; D006801:Humans; D007432:Intraoperative Period; D010535:Laparoscopy; D009609:Nitrous Oxide / Q000009:adverse effects / Q000737:chemistry*; D010529:Peritoneal Cavity; D012007:Rectum / Q000378:metabolism; D012307:Risk Factors
D005740:Gases; D002245:Carbon Dioxide; D009609:Nitrous Oxide