Diagnostic tests and subtypes of dysfunctional breathing in children with unexplained exertional dyspnea

Abstract

Background: Inappropriate hyperventilation during exercise may be a specific subtype of dysfunctional breathing (DB). Objective: To assess whether Nijmegen questionnaire and hyperventilation provocation test (HVPT) are able to differentiate inappropriate hyperventilation from other DB subtypes in children with unexplained exertional dyspnea, and normal spirometry and echocardiography. Methods: The results were compared between a subgroup of 25 children with inappropriate hyperventilation (increased V'E/V'CO 2 slope during a cardiopulmonary exercise test (CPET)) and an age and sex matched subgroup of 25 children with DB without hyperventilation (median age, 13.5 years; 36 girls). Anxiety was evaluated using State-Trait Anxiety Inventory for Children questionnaire.Results: All children were normocapnic (at rest and peak exercise) and the children with hyperventilation had lower tidal volume/vital capacity on peak exercise (shallow breathing). The Nijmegen score correlated positively with dyspnea during the CPET and the HVPT (p = 0.001 and 0.010, respectively) and with anxiety score (p = 0.022). The proportion of children with a positive Nijmegen score (≥19) did not differ between hyperventilation (13/25) and no hyperventilation (14/25) groups (p = 0.777). Fractional end-tidal CO 2 (FETCO 2 ) at 5-min recovery of the HVPT was < 90% baseline in all children (25/25) of both subgroups. Likewise, there was no significant difference between the two subgroups for other indices of HVPT (FETCO 2 at 3-min recovery and symptoms during the test). Conclusion:The validity of the Nijmegen questionnaire and the HVPT to discriminate specific subtypes of dysfunctional breathing, as well as the relevance of the inappropriate hyperventilation subtype itself may both be questioned.

Dysfunctional breathing and its impact on asthma control in children and adolescents

“…The NQ 3 is a 16‐item questionnaire developed to detect hyperventilation and intended as a measurement of “functional respiratory complaints.” 6 , 10 …”

“… 8 , 12 A recent study found a positive correlation both between NQ and dyspnea during a cardiopulmonary exercise test, and between NQ and anxiety score in children with suspected DB. 10 …”

“…The NQ 3 is a 16-item questionnaire developed to detect hyperventilation and intended as a measurement of "functional respiratory complaints." 6,10 Each symptom is given a score from 0 (never happens) to 4 (happens very often). The summarized score ranges from 0 to 64 points, where a score ≥23 points predicts DB.…”

A Case of Acute Conditioned Dyspnea During Tracheostomy Weaning Treated Successfully With Adjunctive Mirtazapine

“…1 In cases where extubation or decannulation are prolonged because of anxiety, dysfunctional breathing (changes in breathing in the absence or in excess of medical pathology) often warrants specific treatment. 2 Mirtazapine, a noradrenergic and specific serotonergic (5HT)-ergic antidepressant, is associated with enhancement of 5HT-ergic and noradrenergic systems in the central nervous system. The noradrenergic effect is attributed to the blockade of inhibitory presynaptic α (α)2-autoreceptors.…”

“…Protocol-based capping trials have led to readiness criteria with high specificity and a positive predictive value for successful decannulation 1 . In cases where extubation or decannulation are prolonged because of anxiety, dysfunctional breathing (changes in breathing in the absence or in excess of medical pathology) often warrants specific treatment 2 …”