[The technique of arthroscopy with nitrous oxide insufflation (author's transl)]

Since April 1977 we have carried out more than 250 arthroscopies using a nitrous oxide insufflation device. Nitrous oxide is completely non-toxic to the tissues and is rapidly absorbed. Unlike carbon dioxide, which is the other commonly used insufflation gas, nitrous oxide does not combine with water to form an acid which can irritate the tissues. Furthermore, it is more rapidly absorbed than air. The normal insufflation pressure of 50 mm Hg is usually sufficient to expand the soft parts of the knee joint to the required degree. Interstitial nitrous oxide emphysema occurred in only 7 cases; it was of limited degree in each case and attributable to initial technical difficulties with the apparatus, selection of an excessive insufflation pressure, or additional stab incision. The nitrous oxide emphysema was always asymptomatic and, in some cases, was not even noticed by the patient. No infections of the knee joint or other serious complication followed insufflation with this device, which incorporated a bacterial filter.