The Hyperventilation Provocation Test (HPTest) associated with end-tidal CO2 pressure (PETCO2) measurement is a diagnostic tool for idiopathic hyperventilation syndrome (HVS). However, interpretation of HPTest remains unclear regarding the relevant PETCO2 values to consider and the occurrence of subjective symptoms. This case-control study aims to identify accurate HPTest measurements for the diagnosis of HVS, regardless of symptoms occurrence.
In a first stage, the investigators will analyze in a prospective way a training cohort of HPTest datas from 74 subjects, involving 37 subjects with complaints and a Nijmegen questionnaire score of ≥23/64 (HVS+) matched on gender, age, height, weight and BMI category with 37 healthy controls without complaints and a Nijmegen questionnaire score of \<23/64 (HVS-)(16). All data will have to be collected by the same equipment and by the same operators in the pulmonology department of the CHU-St Pierre-Brussels between June 2018 and October 2021. To rule out confounding respiratory pathology, each participant will have completed spirometry and methacholine testing, that will have a result within expected normal values. For both cohorts, kinetics of the PETCO2 recorded during each of the 3 phases of the HPTest (adaptation, hyperventilation and recovery) will be mathematically modeled by an curvilinear model with the parameters (A, A', a and a') noted from the kinetic equation (TAU) : TAU \[PETCO2(t)〖=A+a(1-exp〗\^((b-t)/c))\]. For any observed differences in parameters between groups, the Area Under Curves will be estimated at the cut-off that offers the best Sensitivity and Specificity. False negative and false positive rates will be estimated. The probability of a type I error is set at 5%. In a second stage, in order to confirm/infirm the results, a retrospective validation cohort from another care setting, including subjects without confounding pathology, who completed a Nijmegen questionnaire and a HVTest between 2018 and 2021, will be analysed in the same way than the training cohort.
Study Type
OBSERVATIONAL
Enrollment
74
During the HPTest, the subject is comfortably seated in a chair with armrests and breathes in a mouthpiece with a salivary collector and a nasal clamp. Parameters of ventilation and gas exchange are analyzed via an Oxycon ProTM (SN808008) with TripleV-Volume Sensor digital(Jaeger). The HPTest begins with a 3-minutes adaptation phase during which the patient is asked to "breathe normally". During the 3-minutes of voluntary hyperventilation phase, the patient is asked to increase his tidal volume and support a breath rate of at least 30/min in order to reduce his PETCO2 by at least 50%. During the recovery phase of the HPTest, the patient is invited to regain a "natural breathing" for 5 minutes, without guidance on tidal volume or breath rate.
CHU St Pierre
Brussels, Brabant, Belgium
PetCO2 recovery (5min)
PetCO2 at the end (5th minute) of the recovery phase of the HPTest
Time frame: 5 minute of recovery
PetCO2 recovery (3min)
PetCO2 at the end (3d minute) of the recovery phase of the HPTest
Time frame: 3 minute of recovery
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.