Gaseous microemboli in cardiac surgery with cardiopulmonary bypass: the use of veno-arterial shunt as a preventive method

Abstract

Neurological complications are an important cause of morbidity in the postoperative period of cardiac surgery and its incidence reaches up to 75% of patients. An important cause of these events is the formation of microbubbles in the bloodstream during cardiopulmonary bypass. Integrative review was carried out on gaseous microemboli in cardiopulmonary bypass. This study analyzed studies with different methodological approaches, but that address the issue. The result suggests the denitrogenation of blood by hyperoxia dissolved microbubbles in the blood and venoarterial shunt can balance the respiratory parameters changed with hyperoxia.Descriptors: Extracorporeal circulation. Embolism, air. Cognition disorders. Cardiac surgical procedures. ResumoAs complicações neurológicas representam importante causa de morbidade no período pós-operatório de cirurgia cardíaca e sua incidência alcança até 75% dos pacientes. Uma importante causa desses eventos é a formação de microbolhas na corrente sanguínea durante a circulação extracorpórea. Realizou-se revisão integrativa sobre microembolia gasosa na circulação extracorpórea. Esse trabalho analisou estudos com abordagens metodológicas diferentes, mas que contemplam o tema. O resultado sugere que a desnitrogenação do sangue causada pela hiperoxia dissolve microbolhas formadas no sangue e o shunt venoarterial pode equilibrar os parâmetros respiratórios alterados pela hiperoxia.Descritores: Circulação extracorpórea. Embolia aérea. Transtornos cognitivos. Procedimentos cirúrgicos cardíacos.

Cardiovascular effects of hyperoxia during and after cardiac surgery

“…Gas micro‐emboli mostly occur during open procedures such as valve replacement (incidence 1.5–10%) , where they are generated by cavitation in areas of turbulent flow, by injection of solutions into the circuit or by entrainment of gas from both cannulation sites. Improvement of the components of the bypass circuit has substantially diminished the burden of gas micro‐emboli . As most of the aforementioned clinical trials excluded patients undergoing valve surgery, the clinical impact of hyperoxia on gas micro‐emboli cannot be determined based on the available literature about different oxygen levels in cardiac surgical patients.…”

Retrospective Analysis of Air Handling by Contemporary Oxygenators in the Setting of Cardiac Surgery

“…Group 1 patients suffer from a major focal neurologic deficit, going ahead with stupor or coma, whereas the group 2 dysfunctions include confusion, memory deficits, seizures, etc. 3 , 4 ) Overall, the clinical outcome after suffering from GME during cardiac surgery is determined by size and location of the GME, as well as by general status and comorbidities of patients. Massive GME are usually fatal, both in the venous and arterial circulation.…”

Measurement of gaseous microemboli in the prime before the initiation of cardiopulmonary bypass

“…Microemboli, predominantly GME, may partly explain the neurocognitive impairment seen in 30-80% of patients operated with CPB 3,5,6 although there is growing evidence that patient-related factors also play an important role in postoperative cognitive dysfunction. Surgical patients are getting older, with comorbidities, and the inflammatory effects of CPB can also contribute to neurocognitive impairment.…”

“…However, neurological complications still represent an important cause of morbidity in the postoperative period. 3,4 Microembolism, predominantly gaseous microemboli (GME), may partly explain the neurocognitive impairment seen in 30-80% of patients operated with extracorporeal circulation. 3,5,6…”