What gas is used to create pneumoperitoneum -

Ans. is 'c' i.e., CO2 & ''d' i.e., Nitrous dioxide Choice of Gas for pneumoperitoneum* First Pneumoperitoneum was created by filtered room air. Carbon dioxide 8c N2O are now preferred gas because of increased risk of air embolism with room air.* CO2 is used for insufflation as it is 200 times more diffusible than O2, is rapidly cleared from the body by the lungs and will not support combustion.* N2O is only 68% as rapidly absorbed in blood as CO2. N2O has one advantage over CO2 that it has mild analgesic effect, and so causing no pain if diagnostic laparoscopy is performed under local anaesthesia. For short operative procedures like sterilization or drilling, under local anaesthetic N2O may also be used. During prolonged laparoscopic procedure N2O should not be a preferred gas for pneumoperitoneum because it supports combustion better than air.* CO2 when come in contact with peritoneal fluid converts into carbonic acid. Carbonic acid irritates diaphragm causing shoulder tip pain & discomfort in abdomen. Carbonic acid has one advantage also that it alters pH of peritoneal fluid (acidotic changes) and it is mild antiseptic so the chances of infection may be slightly less compared to any other gas.* Helium gas being inert in nature is also tried in many centers but it does not have any added benefit over CO2.