Carbon dioxide insufflation and neurocognitive outcome of open heart surgery

Abstract

Aim

Neurocognitive dysfunction continues to be the bane of open heart surgery despite vast improvements in surgical, anesthetic, and postoperative management. This observational cohort study was carried out to evaluate the efficacy of intraoperative CO₂ insufflation by the field flooding technique in reducing postoperative neurocognitive dysfunction.

Methods

Three hundred randomly selected patients undergoing open heart surgery were observed: 150 (group A) were exposed to CO₂ insufflation, and the other 150 (group B) were not exposed to CO₂. Anesthetic, cardiopulmonary bypass, and myocardial protection techniques were standardized and similar in both groups. Neurocognitive function tests were performed preoperatively, 1 week postoperatively, and after 1 month.

Results

The analysis revealed that neurocognitive dysfunction occurred in 8 of 150 patients in group A (incidence p₁ = 0.053) and 27 of 150 in group B (incidence p₂ = 0.18). The relative risk of neurocognitive dysfunction was 0.30 (p = 0.001, 95% confidence interval 0.14–0.63), implying that CO₂ insufflation is protective against neurocognitive dysfunction. The risk difference was 0.13 (p₂–p₁); this implies that 13% of patients can be prevented from developing neurocognitive dysfunction if exposed to CO₂.

Conclusion

This study confirms the known advantage of the relatively underutilized practice of CO₂ insufflation. We recommend that CO₂ insufflation be performed in all open heart surgery cases to bring down the incidence of neurocognitive dysfunction. This technique is simple to use without any major paraphernalia or additional cost.

Keywords

Brain ischemia carbon dioxide cognition disorders insufflation intracranial embolism neuropsychological tests

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