Carbon Dioxide Insufflation During Cardiac Surgery: A Meta-analysis of Randomized Controlled Trials

Despite the widespread use of carbon dioxide insufflation (CDI) in cardiac surgery, there is still paucity of evidence to prove its benefit in terms of neurologic protection. Therefore, we conducted a meta-analysis of available randomized controlled trials comparing CDI vs standard de-airing maneuvers. Electronic searches were performed to identify relevant randomized controlled trials. Primary outcomes investigated were postoperative stroke, neurocognitive deterioration, and in-hospital mortality. Risk difference (RD) was used as summary statistic. Pooled estimates were obtained by means of random-effects model to account for possible clinical diversity and methodological variation between studies. Eight studies were identified with 668 patients randomized to CDI (n = 332) vs standard de-airing maneuvers (n = 336). In-hospital mortality was 2.1% vs 3.0% in the CDI and control group, respectively (RD 0%; 95% confidence interval [CI] -2% to 2%; P = 0.87; I2 = 0%). Incidence of stroke was similar between the 2 groups (1.0% vs 1.2% in the CDI and control group, respectively; RD 0%; 95% CI -1% to 2%; P = 0.62; I2 = 0%). Neurocognitive deterioration rate was 12% vs 21% in the CDI and control group, respectively, but this difference was not statistically significant (RD: -7%; 95% CI -0.22% to 8%; P = 0.35; I2 = 0%). The present meta-analysis did not find any significant protective effect from the use of CDI when compared with manual de-airing maneuvers in terms of clinical outcomes, including postoperative neurocognitive decline.