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1.  Are there “risk factors” for vasovagal syncope?
2.  With which scenarios is vasovagal syncope usually associated?
3.  What premonitory signs and symptoms may exist for vasovagal syncope? 　

1.  血管迷走神经性晕厥的危险因素有哪些？
2.  血管迷走神经性晕厥常和哪些情况有关？
3.  血管迷走神经性晕厥出现的先兆症状和体征有哪些？

参考答案：

1.血管迷走神经性晕厥的危险因素有哪些？

因为血管迷走神经性晕厥的特殊生理机制尚未明了，因此，很难鉴别可能存在血管迷走神经性晕厥的患者。最近对存在晕厥的患者进行评估发现，年龄小于25岁者（与性别或发作的次数无关）晕厥高发[1]。然而，临床病史对晕厥的再次发生是最有意义的，同时血管迷走神经性晕厥诊断的金标准常包括临床病史和观测（如果可能对患者发作时的观察）[2]。

2.血管迷走神经性晕厥常和哪些情况有关？

麻醉学家发现静脉导管或其他穿刺针（包括硬膜外穿刺针）的使用与之有一定关系[3-5]，通常的相关包括看到血液、失血和突然的应激或疼痛刺激。

值得关注的是，很多在麻醉学杂志上的讨论包含了血管迷走神经性晕厥和坐位下肩部手术的关系，特别是使用肌间沟阻滞时。这种相关性最终尚未被证实，Kahn等[6]和Liguori[7]对接受坐位下肩部手术的患者进行分析，分别发现血管迷走性晕厥的发生率为13%和28%。所观察到的晕厥可能是失血、肌间沟阻滞诱导的心脏反应方式的变化以及外科操作的综合结果。

3.血管迷走神经性晕厥出现的先兆症状和体征有哪些？

晕厥发生前，可立即出现面色苍白、虚弱无力、头晕、打哈欠、恶心、出汗、过度通气、视力模糊和听力下降。如果此时患者可以坐下或躺下，晕厥可以消失，但患者可长时间感觉虚弱无力。体格检查没有发现与血管迷走神经性晕厥相关的特异体征。

Are there “risk factors” for vasovagal syncope?

As specific physiologic triggers have not been clearly identified, it is difficult to identify those patients who may be at risk for vasovagal syncope. Recent evaluations of patients with this form of syncope have noted that an age less than 25, but not gender or frequency of symptoms, has been correlated with greater episodes of syncope (1). A clinical history may, however, be the most suggestive entity for a repeat episode, and the “standard” diagnosis of vasovagal syncope usually involves a clinical history and observation, if possible, of the patient at the time of the symptoms (2).

With which scenarios is vasovagal syncope usually associated?

While anesthesiologists have found an association with the use of intravenous catheters or other needles (including epidural needles) (3-5), common associations include the sight of blood, the loss of blood, and sudden stressful or painful experiences.

Of note, much discussion in the anesthetic literature involves the relationship between vasovagal syncope and shoulder surgery in the sitting position, specifically with the use of an interscalene blockade. While the association has not been demonstrated to be conclusively related, in analyses of patients undergoing shoulder surgery in the sitting position, Kahn et al.  and Liguori (7) noted 13 and 28% incidences, respectively, of vasovagal events. The syncope observed may represent the combination of venous pooling, interscalene block induced changes in heart response patterns, and surgical manipulation. Further investigation into this and other surgeries in warranted.

What premonitory signs and symptoms may exist for vasovagal syncope?

If present, these signs include pallor, weakness, lightheadedness, yawning, nausea, diaphoresis, hyperventilation, blurred vision, and impaired hearing immediately before the syncopal event. If the patient is able to get into a seated or recumbent position, frank syncope may be aborted, however, the patient may have a lingering sensation of weakness. There are no pathognomonic signs from the physical examination which are specifically related to vasovagal syncope.

Question Author: Lawrence Tsen, MD, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School

References:

1.  Sheldon R, Sexton E, Koshman ML. Usefulness of clinical factors in predicting outcomes of passive tilt tests in patients with syncope. Am J Cardiol 2000 Feb 1;85(3):360-4.
2.  Fenton AM, Hammill SC, Rea RF, Low PA, Shen WK. Vasovagal Syncope. Ann Intern Med. 2000;133(9):714-725.
3.  Watkins EJ, Dresner M, Calow CE. Severe vasovagal attack during regional anaesthesia for caesarean section. Br J Anaesth 2000;84(1):118-20
4.  Hart PS, Yanny W. Needle phobia and malignant vasovagal syndrome. Anaesthesia 1998;53(10):1002-4.
5.  Sprung J, Abdelmalak B, Schoenwald PK. Vasovagal cardiac arrest during the insertion of an epidural catheter and before the administration of epidural medication. Anesth Analg 1998;86:1263-5
6.  Kahn RL, Hargett MJ . Beta-adrenergic blockers and vasovagal episodes during shoulder surgery in the sitting position under interscalene block. Anesth Analg 1999;88(2):378-81.
7.  Liguori GA, Kahn RL, Gordon J, Gordon MA, Urban MK The use of metoprolol and glycopyrrolate to prevent hypotensive/bradycardic events during shoulder arthroscopy in the sitting position under interscalene block. Anesth Analg 1998;87:1320-5.


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