Postoperative management of cerebral air embolism: gas physiology for surgeons

Cerebral gaseous microemboli are present in most, if not all, cardiopulmonary bypass-assisted operations. Fortunately, the great majority are subclinical. Clinically significant cases of cerebral air embolism are largely underdiagnosed, undertreated, and underreported. The management of cerebral air embolism has been challenged due to the lack of prospective, randomized studies. Preventive measures that have been implemented throughout the years, resulting from empirically acquired knowledge, have avoided frequent major mishaps. Perfusion accidents, in which massive amounts of gas are pumped into patients, are managed intraoperatively by common-sense heroic measures which, at best, remove 50% of the embolized gas. Postoperative confirmation of a neurologic insult after a cardiopulmonary bypass-assisted operation, in which a cerebral air embolism is likely the source, is one of the most distressing situations a surgical team has to confront, due in part to the lack of pathognomonic diagnostic tools and to the absence of a "scientifically proven" (supported by prospective, randomized studies) therapeutic regimen. In lieu of the latter, we present the physical and physiologic bases that will justify the use of several therapeutic tools when facing a suspected CAE. These tools, when applied rationally, will represent some of the most innocuous modalities in the medical armamentarium.