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摘要

平喘气-正缺氧综合征(POS)是一种罕见的疾病，其特点是直立位时呼吸困难和缺氧，仰卧位时症状缓解。其病因是多因素的，取决于心房间缺损和功能成分，这增加了直立位时从右向左分流。我们报告一例68岁女性高血压，升主动脉扩张，两次轻微中风和一次短暂性脑缺血发作，因严重呼吸困难和低饱和度至71%无氧气供应而入院。患者垂直位时症状加重，平躺时症状缓解。起初，怀疑是肺栓塞，但通过计算机断层扫描和通气/灌注闪烁显像予以驳斥。闪烁显示示踪剂活性在多个器官，这表明一个右向左分流。经食管超声心动图(TEE)显示卵圆孔未闭和持续性咽鼓管瓣导致右向左分流，右心插管显示肺动脉压正常，12 mmHg，排除肺动脉高压，患者行PFO封堵并完全恢复。当怀疑有POS时，TEE和右心导管插管时应考虑体位刺激，以显示直立位右向左分流恶化。在心内科急诊科，肺栓塞是一种罕见但重要的鉴别诊断。

关键字

平稳性呼吸-正缺氧综合征，缺氧，呼吸困难，右向左分流，主动脉疾病1例

介绍

平喘气-正缺氧综合征(POS)是一种罕见而复杂的疾病，其特点是体位性呼吸困难和缺氧，症状和血氧饱和度在仰卧位[1]改善。描述术语platypnea源自希腊语platus(扁平)和pnoia(呼吸)，描述在平卧位[2]时呼吸短促的改善。Orthodeoxia是描述动脉血在直立位置缺氧的术语，由希腊语ortho(直立)和缺氧(少氧)[1]组成。理论上认为，[3]综合征的形成必须同时存在解剖和功能成分。解剖成分为心房间缺损，可发生从右到左的分流。最常见的房间隔缺损是卵圆孔未闭(PFO)，较少的房间隔缺损(ASD)或有窗的房间隔动脉瘤[3]。假设是由于房间隔变形和/或血流转向心房间缺损[3]，功能成分增加了直立位右向左分流。功能成分可能是心脏(chiari网，持续的咽鼓管瓣，心包积液)，主动脉(升主动脉动脉瘤，主动脉根延长或动脉瘤)，肺(肺切除术，肺叶切除术，肺气肿)，骨骼(后凸)或肌肉(单侧膈肌麻痹)[1,4,5]。虽然心房间缺损主要在出生时就存在，但功能部分通常在生活中发育较晚，这解释了延迟发作的POS。呼吸短促是急诊科常见的症状，最常见的是由肺或心血管疾病[6]引起的。我们报告一例POS，呼吸短促最初被认为是由肺栓塞引起的，我们描述了患者在诊断为POS之前进行的全面调查。

案例展示

一个68岁的女性（体面区域（BSA）1.66M2和BMI 23.6 kg / m2），具有甲状腺功能亢进的病史，治疗的高血压，升高的主动脉升高，历史历史两种轻微缺血性卒中和一个瞬态缺血攻击事件录入了心脏病学急诊部。患者呈现出呼吸急促在直立位置和动员到直立位置。患者在仰卧位休息时经历过症状浮雕。在入学前，轻度呼吸困难的发病是大约1个月，患者在走上楼梯时逐渐恶化了呼吸困难。最后几天，直到入学升级而升级，患者在她的房子里走来时经历了呼吸困难。此外，入院前几天，患者在低强度活动中经历了头晕，萎靡不振，轻度胸痛恶化。在心脏病急诊部门，患者呈外外周紫绀，氧饱和度为71％，颈静脉差异。躺下氧气供应（每分钟5升）后，饱和度升高92％。在床上调动直立位置导致呼吸困难和去饱和低于80％。 Arterial blood pressure was 139/88mmHg, heartrate 97 beats per minute and no cardiac murmur was heard. Initially, arterial blood sample without oxygen supply demonstrated oxygen saturation 76%, partial pressure of oxygen 4.7, partial pressure of carbon dioxide 3, and pH 7.54. Blood samples demonstrated normal D-dimer and normal high-sensitive cardiac troponin T. Electrocardiogram (ECG) showed sinus rhythm without signs of ischemia or right ventricular strain. A transthoracic echocardiogram (TTE) demonstrated normal dimensions of the left ventricle, normal ejection fraction, a mild dilation of the aortic root and a tricuspid aortic valve with a trivial insufficiency. It was noted that it was not possible to visualize the right ventricle and atrium. The patient had moderate risk of pulmonary embolism with Well’s Score 3 point (3 points for pulmonary embolism being the most likely cause of symptoms). Because of severe desaturation, dyspnoea and moderate risk of pulmonary embolism, acute computed tomography (CT) angiogram of pulmonary arteries was performed. The patient was known with mild dilation of the ascending aortic, and though less likely than pulmonary embolism, aortic dissection was suspected, and CT of the aorta was performed. Central pulmonary embolism and aortic dissection was refuted. Furthermore, CT angiogram confirmed dilation of the ascending aorta measuring 44 mm with a relatively horizontal course with increased aortic root angulation of 70 degrees and the aortic root with close relation to the right atrium (Figure 1). Due to the persistent dyspnoea, peripheral pulmonary embolism was suspected. Ventilation/perfusion scintigraphy was performed without signs of pulmonary embolism, but tracer activity was observed in kidneys, spleen, stomach, and brain indicating a right-to-left shunt. A transoesophageal echocardiogram (TEE) in supine position demonstrated that the right atrium and superior vena cava being compressed by the dilated aorta. Combination of the dilated aorta compressing the right atrium and a prominent eustachian valve conducted blood flow from the inferior vena cava towards a patent foramen ovale (PFO) (Figure 2). This resulted in a significant right-to-left intracardiac shunt. To further quantify the intracardiac shunt and assess the etiology, a right heart catheterization was performed. This indicated an insignificant left-to-right shunt in supine position, shunt ratio 1.2 and normal pulmonary artery pressure of 12mmHg ruling out pulmonary hypertension (Table 1). The combination of postural dyspnea and desaturation, relief of symptoms in supine position and TEE demonstrating PFO with right-to-left shunt was consistent with POS. Furthermore, pulmonary hypertension was refuted before the patient was referred to percutaneous closure of the PFO. A Cocoon PFO Occluder was successfully implanted. A post procedure TTE was performed without signs of residual shunt. The patient had immediately symptom relief. At 4- and 17-month control, TTE showed a well-placed closure device and no residual shunt. Due to 3 weeks hospitalization, the patient continued experiencing exhaustion a few months after discharged from the hospital.

图1所示。计算机断层摄影图像显示升主动脉向左心室的水平方向。(A)前视图(B)、(C)、(D)前视图、根尖视图和后视图三维图像

图2。Transoesophageal超声心动图。RA,右心房;洛杉矶,左心房。(A)显示持续性咽鼓管瓣(蓝色箭头)和卵圆管未闭(红色箭头)。(B)彩色多普勒显示下腔静脉血流加速(白色箭头)流向未闭卵圆(绿色箭头)

表1。休息时仰卧位右心导管测量

讨论

在上述病例中，患者在确诊为POS之前进行了全面的检查。在心内科急诊科，严重呼吸困难和去饱和的常见原因是肺栓塞。因此，由于严重的降血率为71%，怀疑该患者存在肺栓塞。入院时，患者未提及入院前1个月出现轻度呼吸困难，这是后来调查发现的。入院时深入询问症状是至关重要的，因为肺栓塞通常是急性发作。通气/灌注闪烁成像显示肾、脾、胃和脑的示踪剂活性，提示右向左分流，导致对POS的调查。一般来说，TEE在评估心房和心房间解剖[7]方面更好。因此，TEE是检测PFO和POS的一种有用的诊断工具。平卧位行右心导管置管，无明显分流，说明平卧位分流很小。在直立状态下，需要明显的从右到左分流。据其他研究报道，在进行TEE和右心插管时，通过倾斜试验或模拟直立位的刺激试验(如Valsalva操作)检查体位刺激会增加诊断价值[7,8]。在重度肺动脉高压的病例中，PFO闭塞与右侧压力增加导致症状恶化相关[7,8]。 Therefore, right heart catheterization is crucial in the diagnosing the etiology of POS, ruling out pulmonary hypertension before PFO occlusion [7]. The patient reported in this case had a successful percutaneous catheter-based closure of PFO and gained full recovery. The association between the development of a right-to-left shunt and enlarged aortic root or aortic aneurysm has been described previously [9]. One study demonstrated an association between aorta size, atrial septum deformation and motility, and increased risk of shunting in patients with PFO [10]. Only few cases of patients with POS due to coexisting PFO, persisting eustachian valve and aorta enlargement has been reported [7]. It is suspected that the coexisting of a persisting eustachian valve and a dilated aorta, both contributed to the increased right-to-left shunt in upright position.

结论

肺栓塞是一种罕见的鉴别诊断。严重呼吸困难和缺氧伴体位恶化的患者应怀疑有POS，特别是当肺栓塞被驳斥时。当怀疑有POS时，TEE和右心导管插管时应考虑体位刺激，以显示直立位右向左分流恶化。

同意声明

这个病例报告中的病人已经阅读了这篇文章，看过所有的材料，并书面同意发表它。

参考文献

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