Stendel R, Gramm H J, Schröder K, Lober C, Brock M
Departments of Neurosurgery, Anesthesiology and Critical Care Medicine, and Cardiology and Pulmonology, Benjamin Franklin Medical Center, Freie Universität Berlin, Berlin, Germany.
Anesthesiology. 2000 Oct;93(4):971-5. doi: 10.1097/00000542-200010000-00016.
Venous air embolism has been reported to occur in 23-45% of patients undergoing neurosurgical procedures in the sitting position. If venous air embolism occurs, a patent foramen ovale (PFO) is a risk factor for paradoxical air embolism and its sequelae. Preoperative screening for a PFO is therefore recommended by some investigators. The reference standard for identifying a PFO is contrast-enhanced transesophageal echocardiography (c-TEE). Contrast-enhanced transcranial Doppler ultrasonography (c-TCD) and contrast-enhanced transthoracic echocardiography (c-TTE) are noninvasive alternative methods, but so far there are no studies as to their diagnostic validity in neurosurgical patients.
The sensitivity and specificity of c-TCD and c-TTE in detecting a PFO were determined in a prospective study using c-TEE as the reference standard. Preoperative c-TCD, c-TTE, and c-TEE studies were performed during the Valsalva maneuver after intravenous echo-contrast medium (D-Galactose, Echovist-300, Schering AG, Berlin, Germany) was administered in 92 consecutive candidates (47 men and 45 women; mean age, 51 yr; range, 25-72 yr) before neurosurgical procedures in the sitting position.
A PFO was detected in 24 of the 92 patients (26.0%) using c-TEE. c-TCD correctly identified 22 patients, whereas c-TTE only correctly identified 10. This corresponds to a sensitivity of 0.92 for c-TCD and 0.42 for c-TTE. The negative predictive value was 0.97 for c-TCD compared with 0.83 for c-TTE. The prevalence of a PFO in patients with a posterior fossa lesion was 27%, and in the group with cervical disc herniation was 24% as detected by c-TEE. The incidence of intraoperative venous air embolism was 35% in cases of cervical foraminotomy and 75% in posterior fossa surgery as detected by c-TEE.
c-TCD is a highly sensitive and highly specific method for detecting a PFO. Because c-TCD is noninvasive, it may be more suitable than c-TEE for routine preoperative screening for a PFO. C-TTE is not reliable in detecting a PFO.
据报道，在接受坐位神经外科手术的患者中，23% - 45%会发生静脉空气栓塞。如果发生静脉空气栓塞，卵圆孔未闭（PFO）是反常空气栓塞及其后遗症的一个危险因素。因此，一些研究者建议对PFO进行术前筛查。识别PFO的参考标准是经食管对比增强超声心动图（c - TEE）。经颅对比增强多普勒超声（c - TCD）和经胸对比增强超声心动图（c - TTE）是无创替代方法，但迄今为止尚无关于它们在神经外科患者中诊断有效性的研究。
以前瞻性研究确定c - TCD和c - TTE检测PFO的敏感性和特异性，以c - TEE作为参考标准。在92例连续的手术候选患者（47例男性和45例女性；平均年龄51岁；范围25 - 72岁）于坐位进行神经外科手术前，静脉注射超声造影剂（D - 半乳糖，Echovist - 300，先灵公司，柏林，德国）后，在瓦尔萨尔瓦动作期间进行术前c - TCD、c - TTE和c - TEE检查。
使用c - TEE在92例患者中的24例（26.0%）检测到PFO。c - TCD正确识别出22例患者，而c - TTE仅正确识别出10例。这对应于c - TCD的敏感性为0.92，c - TTE的敏感性为0.42。c - TCD的阴性预测值为0.97，而c - TTE为0.83。经c - TEE检测，后颅窝病变患者中PFO的患病率为27%，颈椎间盘突出症患者组中为24%。经c - TEE检测，颈椎椎间孔切开术病例中术中静脉空气栓塞的发生率为35%，后颅窝手术中为75%。
c - TCD是检测PFO的一种高度敏感和高度特异的方法。由于c - TCD是无创的，它可能比c - TEE更适合用于PFO的常规术前筛查。c - TTE在检测PFO方面不可靠。
