Carbon dioxide insufflation and neurocognitive outcome of open heart surgery.
OBJECTIVE
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.


CONCLUSIONS
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.
Department of Cardiothoracic and Vascular Surgery, Armed Forces Medical College, Pune, India gautampurna@gmail.com.
Gautam
G
Ganguly
Department of Cardiothoracic and Vascular Surgery, Armed Forces Medical College, Pune, India.
Vikas
V
Dixit
Department of Community Medicine, Armed Forces Medical College, Pune, India.
Seema
S
Patrikar
Department of Cardiothoracic and Vascular Surgery, Armed Forces Medical College, Pune, India.
Ravishankar
R
Venkatraman
Department of Neurosciences, Armed Forces Medical College, Pune, India.
Satya Prakash
SP
Gorthi
Department of Cardiothoracic and Vascular Surgery, Armed Forces Medical College, Pune, India.
Nikhil
N
Tiwari
D000328:Adult; D002245:Carbon Dioxide / Q000008:administration & dosage*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods; D002315:Cardiopulmonary Bypass / Q000379:methods; D005260:Female; D006801:Humans; D007327:Insufflation / Q000379:methods*; D007361:Intelligence Tests; D007430:Intraoperative Care / Q000379:methods; D008297:Male; D008875:Middle Aged; D019965:Neurocognitive Disorders / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control; D009483:Neuropsychological Tests; D011183:Postoperative Complications / Q000175:diagnosis / Q000517:prevention & control; D016896:Treatment Outcome
D002245:Carbon Dioxide
Brain ischemia; carbon dioxide; cognition disorders; insufflation; intracranial embolism; neuropsychological tests