Persistence of intra-aortic air after circulatory arrest

Abstract

Circulatory arrest and open aortic anastomosis can result in air entering the arterial system.1Ueda Y. Miki S. Kusuhara K. Okita Y. Tahata T. Yamanaka K. Deep hypothermic systemic circulatory arrest and continuous retrograde cerebral perfusion for surgery of aortic arch aneurysm.Eur J Cardiothorac Surg. 1992; 6: 36-41Crossref PubMed Scopus (98) Google Scholar, 2Sung S.C. Jun H.J. Woo J.S. Simplified retrograde systemic perfusion for removal of air from the aorta in an infant.Ann Thorac Surg. 2001; 71: 362-364Abstract Full Text Full Text PDF PubMed Scopus (1) Google Scholar However, the fate and location of such air is unknown. It is assumed that it embolizes in small peripheral arteries immediately on resumption of normal antegrade circulation. We undertook aortic valve replacement and hemiarch replacement on a 77-year-old man with aortic valve stenosis, a small abdominal aortic aneurysm of 30 mm (A), and acute aortic dissection. Cardiopulmonary bypass was established by femoral arterial and bicaval cannulations. Open distal aortic anastomosis was performed under hypothermic circulatory arrest. We placed the patient in the Trendelenburg head position and used carbon dioxide field flooding. Circulatory arrest time was 17 minutes. Mechanical de-airing of the aorta was done by retrograde femoral arterial perfusion before antegrade circulation was restarted. After transfer to the intensive care unit, the patient's right femoral pulse became unpalpable. A computed tomography (CT) scan was taken to identify the cause at 2 hours after the end of surgery, which corresponded to 6 hours after cessation of the circulatory arrest. An arterial lesion was found at the femoral cannulation site. However, the CT scan also revealed a pocket of intra-aortic air (B and C) at lumbar vertebral level 3-4 (Cover). It was determined that the air had become trapped during the circulatory arrest and had persisted for at least 6 hours, during which time the patient remained supine. There was no indication that the patient sustained an air embolism of any of the abdominal organs. During the femorofemoral bypass surgery for the leg ischemia, the aorta was briefly allowed to self-flush to purge the air through the femoral artery. In clinical situations, opportunities for detecting intra-aortic air after surgery requiring circulatory arrest are rare. Our finding suggests that air introduced during circulatory arrest can remain much longer than expected despite dynamic aortic blood flow and the changes in body position occurring through patient transfer. Download .jpg (.57 MB) Help with files Cover