Clinical evaluation of a new dispersive aortic cannula.

INTRODUCTION: Cerebral injury is a serious complication in open-heart surgery. Once it occurs, it causes significant disability and death. We developed a novel dispersive aortic cannula named the Stealth Flow cannula and used it as a standard aortic cannula in cardiopulmonary bypass. The aim of this study was to evaluate the efficiency of this aortic cannula. METHODS: A total of 182 consecutive patients undergoing cardiac surgery using cardiopulmonary bypass were studied. The patients were divided into two groups: the Soft-Flow cannula group (n = 89) and the Stealth Flow cannula group (n = 93). Patients with a shaggy aortic arch were excluded from this study because the cannulae were inserted at the ascending aorta with a cannula tip directed toward the aortic root in these cases. Patients with multiple arterial perfusion sites were also excluded. Complications including early mortality, perioperative stroke, and intraoperative aortic injury were compared between the two groups. RESULTS: Age, operative procedure, cardiopulmonary bypass time, and the Japan SCORE were not significantly different between the groups. In comparisons between the Stealth Flow and Soft-Flow groups, the incidences of early mortality, perioperative stroke, intraoperative aortic dissection, and all complications were 1.08% versus 1.12% (p = 0.98), 1.1% versus 2.2% (p = 0.53), 0% versus 1.1% (p = 0.33), and 1.1% versus 3.4% (p = 0.29), respectively. The incidence of major cardiovascular events, including early death, perioperative stroke, and aortic dissection, was not different. CONCLUSIONS: The Stealth Flow cannula, which was designed based on our previous experimental study, contributed to reducing cerebral and aortic events as much as the Soft-Flow cannula in the present clinical study.

Interference with pulse oximetry by the Stealth Station™ Image Guidance System.

BACKGROUND: A pulse oximeter is one of the most important monitors to save patients undergoing anesthesia and monitored sedation. The authors report a case of orthopedic surgery, in which interference of pulse oximetry occurred when using a Stealth Station™ navigation system (Medtronic Sofamor Danek, Memphis, TN). Applying a black plastic shield (Masimo Ambient Shield: Masimo Corporation, Irvine, CA) completely eliminated the interference. CASE PRESENTATION: A 37-year-old male patient with a giant cell tumor of the left femur was scheduled to undergo curettage of the femur using an intraoperative CT three-dimensional imaging system (O-arm™) and Stealth Station™ navigation system. During the surgery, the SpO2 value, which was maintained between 97 and 99% until the time, disappeared suddenly with abnormal pulse wave. Because a distortion in the SpO2 value was reproduced by repeated movement of cameras on the head of the Stealth Station™ navigation system, we recognized that the interference signal was coming from the navigation system. To eliminate the infrared light, the pulse oximetry probe was covered with a black plastic shield and the interference was completely eliminated. CONCLUSIONS: The Stealth Station™ navigation system was found to interfere with the SpO2 value, and a black plastic shield was useful for eliminating the interfering signal. Anesthesiologists should understand the risk of interference by the neuro-navigation system and know how to solve the problem.