AIM: To compare the safety and efficacy of carbon dioxide(CO2) and air insufflation during gastric endoscopic submucosal dissection(ESD).METHODS: This study involved 116 patients who underwent gastric ESD between January and December 2009.After eliminating 29 patients who fit the exclusion criteria,87 patients,without known pulmonary dysfunction,were randomized into the CO2 insufflation(n = 36) or air insufflation(n = 51) groups.Standard ESD was performed with a CO2 regulation unit(constant rate of 1.4 L/min) used for patients undergoing CO2 insufflation.Patients received diazepam for conscious sedation and pentazocine for analgesia.Transcutaneous CO2 tension(Ptc CO2) was recorded 15 min before,during,and after ESD with insufflation.Ptc CO2,the correlation between Ptc CO2 and procedure time,and ESD-related complications were compared between the two groups.Arterial blood gases were analyzed after ESD in the first 30 patients(12 with CO2 and 18 with air insufflation) to assess the correlation between arterial blood CO2 partial pressure(Pa CO2) and Ptc CO2.RESULTS: There were no differences in respiratoryfunctions,median sedative doses,or median procedure times between the groups.Similarly,there was no significant difference in post-ESD blood gas parameters,including Pa CO2,between the CO2 and air groups(44.6 mm Hg vs 45 mm Hg).Both groups demonstrated median p H values of 7.36,and none of the patients exhibited acidemia.No significant differences were observed between the CO2 and air groups with respect to baseline Ptc CO2(39 mm Hg vs 40 mm Hg),peak Ptc CO2 during ESD(52 mm Hg vs 51 mm Hg),or median Ptc CO2 after ESD(50 mm Hg vs 50 mm Hg).There was a strong correlation between Pa CO2 and Ptc CO2(r = 0.66; P < 0.001).The incidence of Mallory-Weiss tears was significantly lower with CO2 insufflation than with air insufflation(0% vs 15.6%,P = 0.013).CO2 insufflation did not cause any adverse events,such as CO2 narcosis or gas embolisms.CONCLUSION: CO2 insufflation during gastric ESD results in similar blood gas levels as air insufflation,and also reduces the incidence of Mallory-Weiss tears. AIM: To compare the safety and efficacy of carbon dioxide (CO2) and air insufflation during gastric endoscopic submucosal dissection (ESD). METHODS: This study involved 116 patients who underwent gastric ESD between January and December 2009. After eliminating 29 patients who fit the exclusion criteria, 87 patients without known pulmonary dysfunction, were randomized into the CO2 insufflation (n = 36) or air insufflation (n = 51) groups. Lastard ESD was performed with a CO2 regulation unit (constant rate of 1.4 L / min) used for patients undergoing CO2 insufflation. Patients received diazepam for conscious sedation and pentazocine for analgesia. Transcutaneous CO2 tension (Ptc CO2) was recorded 15 min before, during, and after ESD with insufflation. Ptc CO2, the correlation between Ptc CO2 and procedure time , and ESD-related complications were compared between the two groups. Arterial blood gases were analyzed after ESD in the first 30 patients (12 with CO2 and 18 with air insufflation) to assess the corre There are no differences in respiratoryfunctions, median sedative doses, or median procedure times between the groups. Similarly, there was no significant difference in post-ESD blood gas parameters , including PaCO 2, between the CO 2 and air groups (44.6 mm Hg vs 45 mm Hg) .Both groups showed median p H values ​​of 7.36, and none of the patients exhibited acidemia. No significant differences were observed between the CO 2 and air groups with respect to baseline Ptc CO2 (39 mm Hg vs. 40 mm Hg), peak Ptc CO2 during ESD (52 mm Hg vs 51 mm Hg), or median Ptc CO2 after ESD (50 mm Hg vs 50 mm Hg). Where was a Strong incidence between Pa CO2 and Ptc CO2 (r = 0.66; P <0.001). The incidence of Mallory-Weiss tears was significantly lower with CO2 insufflation than with air insufflation (0% vs 15.6%, P = 0.013) not cause any adverse events, such as CO2 narcosis or gas embolisms. CONCLUSION: CO2 insufflation during gastric ESD results in similar blood gas levels as air insufflation, and also reduces the incidence of Mallory-Weiss tears.