“The Research of the Angels’ Sex!” Postoperative Delirium and Cardiopulmonary Bypass Correlation

Postoperative delirium (POD) after cardiac surgery with cardiopulmonary bypass is a major problem. Potential pathways of delirium include neurotransmitter interference, global cognitive disorder, and neuroinflammation. The development of delirium after cardiac surgery is associated with worse outcomes in the perioperative period. Multiple interventions are being explored for the prevention and treatment of delirium. In cardiac surgery, the exposure to cardiopulmonary bypass and the stress endured by the patient produce significant inflammation, and the processes of neuroinflammation provides a logical pathway. Gas microemboli are considered a cause of neurocognitive deficits. When a microbubble occludes a blood vessel, hypoxia will occur downstream of the blockage. The duration of hypoxia and the deleterious effects of this hypoxia will very much depend on the size and number of gas microemboli as well as on the gas composition of these microbubbles. At the same time, the microbubble will induce local inflammation with edema formation, which will increase the cerebral area at risk. In these circumstances, the use of an efficient device (venous reservoir and oxygenator module) could be crucial in removal and reduce the gas microemboli. However, aspects related to gaseous microembolic activity are often related in cardiac surgery to the management of deairing before and after removal of the cross-clamp and to the carbon dioxide management technique of the field. 1 O'Neal J.B. Shaw A.D. Predicting, preventing, and identifying delirium after cardiac surgery. Perioper Med (Lond). 2016; 5: 7https://doi.org/10.1186/s13741-016-0032-5 Crossref PubMed Google Scholar We read with great interest the article “Processed Electroencephalographic Use During Anesthesia and Outcomes: Analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database” by Lombard and coworkers. 2 Lombard F.W. Roy S. Shah A.S. Feng X. Shotwell M.S. Kertai M.D. Processed electroencephalographic use during anesthesia and outcomes: analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database. Ann Thorac Surg. 2022; 114: 1688-1694https://doi.org/10.1016/j.athoracsur.2021.09.049 Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar In this interesting large retrospective database study, the authors found no association between processed electroencephalography use during cardiac surgery and postoperative neurologic outcomes, such as POD, stroke, encephalopathy, or coma. In this context, the underlying mechanisms behind delirium are not fully understood. Several hypotheses exist for the pathophysiologic mechanism of delirium, such as neuroinflammation. The roles of perioperative processed electroencephalography, microembolic activity monitoring, and biomarkers in POD after cardiac surgery are promising but not yet fully elucidated. 2 Lombard F.W. Roy S. Shah A.S. Feng X. Shotwell M.S. Kertai M.D. Processed electroencephalographic use during anesthesia and outcomes: analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery Database. Ann Thorac Surg. 2022; 114: 1688-1694https://doi.org/10.1016/j.athoracsur.2021.09.049 Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar In this context, it would be necessary to integrate these aspects to establish a cause and effect relationship in a multifactorial context that predisposes to POD (Figure 1). Processed Electroencephalographic Use During Anesthesia and Outcomes: Analysis of The Society of Thoracic Surgeons Adult Cardiac Surgery DatabaseThe Annals of Thoracic SurgeryVol. 114Issue 5PreviewThis study assessed associations between processed electroencephalographic (pEEG) use during anesthesia, surgery- and anesthesia-related risk factors, and neurologic outcomes and mortality after cardiac surgery. Full-Text PDF Neuromonitoring and Postoperative Neurocognitive OutcomesThe Annals of Thoracic SurgeryVol. 115Issue 3PreviewWe appreciate the letter and comments from Condello and Condello1 in response to our publication on the association between intraoperative processed electroencephalogram (pEEG) use and adverse neurologic outcomes after cardiac surgery.2 Using data from The Society of Thoracic Surgeons National Database, collected between 2017 and 2019, we found no association between pEEG use and adverse neurologic outcomes. As we pointed out in our paper, and echoed by Drs Condello,1 the causes of neurologic complications are multifactorial. Full-Text PDF