Schwarz G, Fuchs G, Weihs W, Tritthart H, Schalk H V, Kaltenböck F
Department of Anesthesiology, University of Graz, Austria.
J Neurosurg Anesthesiol. 1994 Apr;6(2):83-8. doi: 10.1097/00008506-199404000-00003.
A persisting foramen ovale (PFO) is the most common cause of paradoxical air embolism. To detect right-to-left shunting, transthoracic contrast echocardiography was performed preoperatively in 301 patients scheduled for neurosurgical procedures in the sitting position. Echocardiography yielded evaluable results in 285 patients (94.7%). In 72 of 285 patients (25.2%), a PFO was diagnosed on the basis of contrast echo signals appearing in the left atrium or ventricle within 5 heart cycles after application of contrast medium via a peripheral vein. If echo signals appeared in the left heart after more than 5 heart cycles, an intrapulmonary right-to-left shunt was considered (11 patients, 3.9%). Venous air embolism (VAE) occurred in 27.4% of 226 patients operated on in the sitting position and in none of the 59 patients operated on in a nonsitting position. We conclude that the sitting position during neurosurgery should be avoided in patients with preoperative evidence of a right-to-left shunt at contrast echocardiography to reduce the risk of paradoxical air embolism (PAE).
持续性卵圆孔未闭（PFO）是反常空气栓塞最常见的原因。为了检测右向左分流，对301例计划采取坐位进行神经外科手术的患者术前进行了经胸对比超声心动图检查。超声心动图在285例患者（94.7%）中获得了可评估的结果。在285例患者中的72例（25.2%）中，根据经外周静脉注入造影剂后5个心动周期内左心房或心室内出现的造影回声信号诊断为PFO。如果在超过5个心动周期后左心出现回声信号，则考虑存在肺内右向左分流（11例患者，3.9%）。226例采取坐位手术的患者中27.4%发生了静脉空气栓塞（VAE），而59例非坐位手术的患者中均未发生。我们得出结论，对于术前经对比超声心动图证实存在右向左分流的患者，神经外科手术时应避免采取坐位，以降低反常空气栓塞（PAE）的风险。
