Looking for an alternative to hard-to-find propofol for colonoscopies? Do like the dentists do and try nitrous oxide. The inert gas provides comparable sedation and analgesia and allows patients quicker recovery times compared to IV sedation, according to a systematic review published online this month in Alimentary Pharmacology & Therapeutics.

An equal mix of nitrous oxide (N2O) and oxygen delivers analgesia and sedation in just 60 seconds and has a short recovery time of 1 to 5 minutes. "This potentially makes it an ideal agent for outpatient procedures like lower gastrointestinal endoscopy," write the authors from Derriford Hospital in Plymouth, England. "Patients who live alone or who wish to drive home may in particular benefit from the rapid recovery of psychomotor function seen when nitrous oxide gas is used."

The researchers looked at 11 randomized trials with a total of 623 patients who had a colonoscopy or flexible sigmoidoscopy. Patients who received nitrous oxide before and during the beginning of a colonoscopy recovered quicker and were ready for discharge sooner than those who received IV sedation. Patient pain scores were similar for nitrous oxide and IV sedation during colonoscopies.

Nitrous oxide was less successful in helping control pain during flexible sigmoidoscopies. Headache was the most common side effect with the gas, write the authors.

Nitrous oxide has been used for its sedative and analgesic properties since 1844. The gas (50% nitrous oxide and 50% oxygen) is common in dental offices and birthing suites. Currently, researchers in Australia are studying a 70% nitrous oxide gas for maintaining anesthesia in major surgical procedures, write the authors.

"In many countries, including the United Kingdom and the USA, the use of propofol infusions mandates the continuous presence of anesthetic trained personnel, which increases cost," write the authors. They argue that the higher personnel cost of IV sedation and the shortage of propofol make nitrous a viable possibility.

"Nitrous oxide," write the authors, "has the potential to improve patient flow through the endoscopy department."

Kent Steinriede

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