Clinical characteristics and hemodynamic responses to head-up tilt test in children and adolescents with unexplained sighing

Objective Sighing is a common symptom in children and adolescents. In this study, we explored the clinical characteristics and hemodynamic responses to head-up tilt test (HUTT) in children and adolescents with unexplained sighing. Methods One hundred ninety-two children and adolescents complaining of unexplained sighing were enrolled as study group after excluding chest wall, lung, heart diseases, and psychogenic disorders. Sixty-nine healthy individuals were enrolled as control group. All the subjects underwent HUTT. Results Nitroglycerin-stimulated HUTT positive rate was higher in the study group than the control group (24.0% vs 10.1%, P = 0.014). In total, 32.3% of patients with sighing had positive responses to HUTT, which was higher than that of healthy individuals (32.3% vs 15.9%, P = 0.009). Among 62 cases with positive responses to HUTT in the study group, 48 cases were vasoinhibitory type vasovagal syncope (VVS), 5 cases were mixed type VVS, 3 cases were cardioinhibitory type VVS, 5 cases were postural tachycardia syndrome, and one case was orthostatic hypertension. Sighing patients with positive responses to HUTT had female dominance (54.8% vs39.2%, P = 0.045), older mean age (9.6 ± 2.8 vs 8.1 ± 2.7 years old, P = 0.001), higher basic systolic blood pressure (104.8 ± 10.4 vs 101.1 ± 9.9 mmHg, P = 0.019), and higher diastolic blood pressure (66.0 ± 7.5 vs 62.9 ± 9.2 mmHg, P = 0.021) compared with those of negative responses. Conclusions Nearly one-third of children and adolescents with unexplained sighing had positive responses to HUTT, demonstrating that sighing was related to dysfunction of the autonomic nervous system. Elder female patients with higher systolic and diastolic blood pressure were more likely to have positive responses to HUTT.