Background

Hyperventilation provocation test (HVPT) is one of the criteria for hyperventilation syndrome (HVS) diagnostic. It can be positive on induced symptoms or prolonged hypocarbia, the latter usually requiring a pulmonary function test (PFT) laboratory resources.

Objectives

To determine the proportion of children with positive HVPT only on hypocarbia to discuss whether the involvement of a PFT laboratory is justified at first assessment.

Methods

Monocentre retrospective study (2021?2022) conducted in all children seen for suspected HVS.

Results

We retrieved 43 files of children (males 13 (30.2%)) aged 14.4 (7.2 to 17.5) years, among whom 38 (88.4%) had associated asthma. Nearly all children were referred with respiratory complains suggestive of HVS (39, 90.7%) while 29 (67.4%) children had extra-respiratory symptoms (4 with only extra-respiratory symptoms). Median [IQR] Nijmegen score was 23 [18.5; 29.5](25 ?23 points).

Six (14%) HVPT were negative. Among the 37/43 (86%) children with positive HVPT, 33/37 (89.2%) reported at least two symptoms recognized as occurring in daily life, and four out of 37 (10.8%) had only a prolonged hypocarbia. Eighteen out of 37 children (48,7%) had both ?2 induced symptoms and prolonged hypocarbia.

Nijmegen score result was not related to that of HVPT (Fisher exact test > 0.05).

Conclusion

In a population of 43 children (with asthma in 88.4%) with a suspicion of HVS essentially based on respiratory symptoms, the positivity of HVPT was rarely based only on prolonged hypocarbia. Our results are in favour to assess the HVPT on symptoms at first and to refer for capnia monitoring only children with a negative HVPT.