Carbon dioxide flooding to reduce postoperative neurological injury following surgery for acute type A aortic dissection: a prospective, randomised, blinded, controlled clinical trial, CARTA study protocol - objectives and design

INTRODUCTION: Neurological complications after surgery for acute type A aortic dissection (ATAAD) increase patient morbidity and mortality. Carbon dioxide flooding is commonly used in open-heart surgery to reduce the risk of air embolism and neurological impairment, but it has not been evaluated in the setting of ATAAD surgery. This report describes the objectives and design of the CARTA trial, investigating whether carbon dioxide flooding reduces neurological injury following surgery for ATAAD. METHODS AND ANALYSIS: The CARTA trial is a single-centre, prospective, randomised, blinded, controlled clinical trial of ATAAD surgery with carbon dioxide flooding of the surgical field. Eighty consecutive patients undergoing repair of ATAAD, and who do not have previous neurological injuries or ongoing neurological symptoms, will be randomised (1:1) to either receive carbon dioxide flooding of the surgical field or not. Routine repair will be performed regardless of the intervention. The primary endpoints are size and number of ischaemic lesions on brain MRI performed after surgery. Secondary endpoints are clinical neurological deficit according to the National Institutes of Health Stroke Scale, level of consciousness using the Glasgow Coma Scale motor score, brain injury markers in blood after surgery, neurological function according to the modified Rankin Scale and postoperative recovery 3 months after surgery. ETHICS AND DISSEMINATION: Ethical approval has been granted by Swedish Ethical Review Agency for this study. Results will be disseminated through peer-reviewed media. TRIAL REGISTRATION NUMBER: NCT04962646.