舌下含化硝酸甘油直立倾斜试验对儿童不明原因晕厥的诊断研究

目的 探讨舌下含化硝酸甘油直立倾斜试验对不明原因晕厥患儿的诊断价值。方法 对25例不明原因晕厥的患儿(晕厥组)及10例无晕厥史的正常健康儿童(对照组)先行基础直立倾斜试验,阴性者再行舌下含化硝酸甘油直立倾斜试验(4～6μg／kg,最大量不超过300μg)。结果 基础直立倾斜试验在晕厥组的阳性率为48％(12／25),对照组为0;舌下含化硝酸甘油直立倾斜试验在晕厥组阳性率为80％(20／25),对照组为20％(2／10);舌下含化硝酸甘油直立倾斜试验诊断的敏感度、特异度及诊断价值均为80％。两组患儿中仅有1例在试验中出现头痛,但能坚持试验完成。结论 舌下含化硝酸甘油直立倾斜试验对诊断儿童血管迷走性晕厥具有良好的敏感性和特异性,且具有操作简便、不良反应小的特点。值得推广应用。

Head-up tilt testing potentiated with sublingual nitroglycerin for the diagnosis of unexplained syncope in children

OBJECTIVE: Syncope is one of the common problems in clinical pediatrics. In recent years, vasovagal reflex was identified as the most common reason for unexplained syncope. Head-up tilt test (HUT) was regarded as one of the important diagnostic criteria. But the sensitivity of baseline head-up tilt test (BHUT) is low. To improve the sensitivity of HUT, we evaluated the diagnostic value of head-up tilt testing potentiated with sublingual nitroglycerin (SNHUT) in children with unexplained syncope. METHODS: Twenty-five patients (11 male and 14 female, mean age 11.8 +/- 2.1 years, ranged from 8 to 15) with unexplained syncope and 10 healthy children in control group (5 male and 5 female, mean age 11.4 +/- 2.1 years, ranged from 9 to 15) were studied. The patients and healthy children were tilted upright to 60 degrees for 45 minutes at BHUT. If syncope did not occur, sublingual nitroglycerin (4 - 6 microg/kg, maximum dose 300 microg) was administered, and continued at same degree for 20 minutes. RESULTS: Compared with controls, there was no significant difference in sex, age, supine blood pressure and supine heart rate of syncopal group (P > 0.05). During BHUT, 12 patients (48%) and none of the controls had positive response, whereas another 8 patients and 2 controls had positive response during SNHUT. In syncopal group, total positive rate was 80%. The sensitivity, specificity, and diagnostic value of SNHUT were all 80%. During SNHUT, the mean time to positive response was 5.9 +/- 2.9 minutes (from 4 to 11 minutes), and only 1 patient had mild headache. CONCLUSION: Head - up tilt testing potentiated with sublingual nitroglycerin (4 - 6 microg/kg, maximum dose 300 microg) as pharmacological provocation test was a useful and an objective diagnostic tool for evaluating vasovagal syncope in children.