Patent Foramen Ovale, Bubble Test, and Major Spine Surgery

POSTOPERATIVE paradoxical embolism resulting from patent foramen ovale (PFO) is a serious complication associated with major surgery. The prevalence of PFO in the general population ranges from 10 to 15% (contrast echocardiography1) to 27.3% (autopsy series). Preoperative diagnosis of PFO is rarely performed except in special settings such as surgery in the sitting position. In this case, a 68-yr-old patient, having undergone thoracolumbar laminectomy and arthrodesis (T12–L1 levels), presented with a bilateral segmentary pulmonary embolism and a left parietooccipital stroke on postoperative day 1. Because of both venous and arterial embolism, PFO was suspected and confirmed with transesophageal echocardiography sensitized with the bubble test.2Contrast material was prepared by mixing 9 ml normal saline with 1 ml air through a three-way stopcock. This is known to produce 152 ± 79 microbubbles/mm³with a diameter of 30–100 μm. A PFO is considered to be present when at least one bubble is seen in the left atrium (LA) within three cardiac cycles after total opacification of the right atrium3(RA, dotted line ) (see Supplemental Digital Content 1, which is a video showing bubbles in the left atrium immediately after total opacification of the right atrium, https://links.lww.com/ALN/A595). The arrow  shows right-to-left shunting across the septum secundum not far from the aorta (Ao). Echocardiography with the bubble test is a safe, sensitive, and specific method to detect PFO. We suggest that systematic, prospective evaluation with bubble testing might be used for high-risk patients undergoing major spine surgery.