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.

Efficacy of carbon dioxide insufflation for cerebral and cardiac protection during open heart surgery: a systematic review and meta-analysis.

In spite of widespread application around the world, there has been controversy on the cerebral and cardiac protection efficacy of carbon dioxide insufflation (CDI) during open heart surgery. To make a comprehensive evaluation, we screened all relevant published randomized controlled trials to perform the first systematic review and meta-analysis for CDI during open heart surgery. We searched PubMed, EMBASE, the Cochrane Controlled Clinical Trial register, WANFAN, CQVIP, and CNKI database for published articles. Randomized controlled trials were included when the research provided data of neurological complications postoperatively, creatinine kinase, MB isoenzyme (CK-MB) on the first postoperative day, or all-cause mortality. We chose a fixed-effects model when the trials showed low heterogeneity, otherwise a random effects model was used. The quality of studies was assessed by modified Jadad scale. Four studies were included in this meta-analysis. The overall pooled relative risk (RR) for neurological complications was 1.59, 95% confidence interval (CI) = [0.57, 4.46], and the z-score for overall effect was 0.89 (P = 0.37). The standardized mean difference of the CK-MB between groups was 1.15, 95% CI = [-1.27, 3.56], and the z-score for overall effect was 0.93 (P = 0.35). The overall pooled RR for all-cause mortality was 0.5, 95% CI = [0.16, 1.64], and the z-score for overall effect was 1.14 (P = 0.25). There was no significant difference between groups. Because of the insufficiency of powerful evidences, the cerebral and cardiac protection efficacy of CDI during open heart surgery needs to be further verified by more high-quality trials.

Tracheal gas insufflation for the prevention of morbidity and mortality in mechanically ventilated newborn infants.

BACKGROUND: Tracheal gas insufflation (TGI) is a technique where a continuous flow of gas is instilled into the lower trachea during conventional mechanical ventilation. TGI can improve carbon dioxide removal with lower ventilation pressures and smaller tidal volumes, potentially decreasing secondary lung injury and chronic lung disease (CLD). OBJECTIVES: To assess whether, in mechanically ventilated neonates, the use of tracheal gas insufflation reduces mortality, CLD and other adverse clinical outcomes without significant side effects. SEARCH STRATEGY: Searches were made of MEDLINE 1966 to December 2001, CINAHL 1982 to December 2001, the Cochrane Controlled Trials Register (Cochrane Library, Issue 4, 2001) and conference and symposia proceedings. SELECTION CRITERIA: Randomised controlled trials (RCT) that include newborn infants who are mechanically ventilated, and compare TGI during conventional mechanical ventilation (CMV) with CMV alone. Primary outcomes - mortality, CLD and neurodevelopmental outcome; secondary outcomes - air leak, intraventricular haemorrhage, periventricular leukomalacia, duration of mechanical ventilation, duration of respiratory support, duration of oxygen therapy, duration of hospital stay, retinopathy of prematurity, immediate adverse effects. DATA COLLECTION AND ANALYSIS: Each reviewer assessed eligibility, trial quality and extracted data separately. Study authors were contacted for additional information if necessary. MAIN RESULTS: Only one small study was found to be eligible. This study found no evidence of effect on mortality, CLD or age at first extubation. The total duration of ventilation was 9.3 days shorter in the TGI group (95% CI from 15.7 to 2.9 days shorter). The age at complete weaning from ventilation was 26 days shorter in the TGI group (95% CI from 46 to 6 days shorter). There was no evidence of effect on the total duration of respiratory support, oxygen therapy or hospital stay. REVIEWER'S CONCLUSIONS: There is evidence from a single RCT that TGI may reduce the duration of mechanical ventilation in preterm infants - although the data from this small study do not give sufficient evidence to support the introduction of TGI into clinical practice. The technical requirements for performing TGI (as performed in the single included study) are great. There is no statistically significant reduction in the total duration of respiratory support or hospital stay. TGI cannot be recommended for general use at this time.

The mouse as a model to study adhesion formation following endoscopic surgery: a preliminary report.

Our aim was to investigate the feasibility of a mouse model to study adhesion formation following endoscopic surgery. Following preliminary studies to establish anaesthesia and pneumoperitoneum pressure, a prospective randomized study was carried out to investigate the effect of CO2 pneumoperitoneum on postoperative adhesions. In group I (control group), the duration of pneumoperitoneum was shorter than 5 min. In groups II, III and IV, pneumoperitoneum was maintained for 60 min without flow, with a continuous low flow (1 ml/min) and a continuous high flow (10 ml/min) through the abdominal cavities of the mice using non-humidified CO2, respectively. Adhesions were scored after 7 days by laparotomy. The total adhesion scores were 0.9 +/- 0.8 (n = 15) in control group, 2.4 +/- 0.8 (n = 15) (P < 0.001 versus control group) in group II with no flow, 2.6 +/- 1.3 (n = 15) (P < 0.001 versus control group) in group III with a continuous low flow and 4.3 +/- 0.9 (n = 15) (P < 0.001 versus control group and P < 0.001 versus group II and III) in group IV with a continuous high flow. In conclusion, the mouse can be used as a model to study adhesion formation following endoscopic surgery. Duration of CO2 pneumoperitoneum is a co-factor in adhesion formation.