An interventional study of Hypercapnic hyperoxic ventilatory response and Hypoxic eucapnic ventilatory response in Hyperventilation Syndrome, Hypercapnia and Hypoxia, sponsored by Centre Hospitalier Universitaire Saint Pierre. Completed at 1 site in Belgium. Open to participants aged 18 Years to 99 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2022-01-12.
Sponsored by Centre Hospitalier Universitaire Saint Pierre · Not applicable, Interventional, and Diagnostic
For almost a century, many hypotheses have converged on the idea of altered chemosensitivity in patients suffering from hyperventilation syndrome (HVS).
Given the evolution of current technical equipment and the ability to maximise true positives in HVS ( using the revised hyperventilation provocation test), it seems reasonable to investigate central and peripheral chemosensitivities in HVS subjects.
In the inter-war period, many medical investigators who studied the hyperventilation syndrome (HVS) had already questioned the chemosensitivity to CO2 in HVS patients, without being able to explore it for all intents and purposes.
It was subsequently observed that although HVS is not systematically linked to manifest resting hypocapnia, it is nevertheless systematically correlated with significant variability and complexity of ventilation.
This is consistent with the observations of an increased plant gain in HVS, to be related to an increased loop gain (due to instability of controller gain feedback).
On the other hand, some authors already noted that, when capnia is chronically compromised in HVS, it can be greatly altered by small, transient and barely perceptible increases in VE: a 10% increase in VE could indeed halve PetCO2, while a sigh would be able to decrease PetCO2 by up to 15mmHg.
More recently, teh assumption was made that peripheral chemosensitivity may be impaired in HVS patients.
For all these considerations, it seems reasonable to investigate central and peripheral chemosensitivities in identified HVS subjects on the basis of an objective test, such as the induced hyperventilation test.
156 studies on the registry are indexed under Hypercapnia; 31 are open to participants now.
This study's enrollment of 24 is below the median of 36 across 120 interventional studies indexed under Hypercapnia.
Browse Hypercapnia studies →Centre Hospitalier Universitaire Saint Pierre is the lead sponsor of 78 studies on the registry; 12 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
subjects with no complaint AND a Nijmegen questionnaire score of \< 23/64 AND a negative hyperventilation provocation test (criteria revised in 2021) (HVS-)
Diagnostic Test: Hypercapnic hyperoxic ventilatory response · Diagnostic Test: Hypoxic eucapnic ventilatory response
subjects with complaints AND a Nijmegen questionnaire score of ≥23/64 AND a negative hyperventilation provocation test (criteria revised in 2021) (HVS+)
Diagnostic Test: Hypercapnic hyperoxic ventilatory response · Diagnostic Test: Hypoxic eucapnic ventilatory response
The hypercapnic ventilatory response (HCVR) described by Read in 1967 (Read's rebreathing method) is a clinical way to assess the central and peripheric sensitivity to CO2, using a small bag (4-6 l) to achieve prompt equilibrium between the apparatus compartments and the lungs. By rebreathing a hyperoxic mixture with an initial composition of 70% O2, 7% CO2 and 23% N2, this equilibrium is assumed to be achieved after 15 seconds of rebreathing, when the relationship between VE and PetCO2 has become linear.
The hypoxic eucapnic ventilatory response (HOVR) is a clinical way to assess the peripheric chemosensitivity to O2, using a small bag (4-6 l) to rebreathe a gas mixture initially composed of 20% O2, 0% CO2 and Δ% N2. Eucapnia is achieved by the activation of a CO2 reabsorption cell during the course of the test.
The slope of the ventilatory response to hypercapnia (HCVR)
Ventilation increase (litres/min) per unit increase in PetCO2 (mmHg) using Read's method
Time frame: baseline - during the test
The slope of the ventilatory response to hypoxia (HOVR)
Ventilation increase (litres/min) per unit decrease in SpO2 (%) using Read's method
Time frame: baseline - during the test
Ventilatory recruitment threshold (VRT) of the HCVR
From the average baseline ventilation and PetCO2, the VRT id the PetCO2 level at which the ventilatory response is activated
Time frame: baseline - during the test
Ventilatory recruitment threshold (VRT) of the HOVR
From the average baseline ventilation and SpO2, the VRT is the level of SpO2 at which the ventilatory response is activated
Time frame: baseline - during the test
Extrapolated apnoeic threshold of the HCVR
PetCO2 level above which apnoea (zero ventilation) is disrupted, obtained from the extrapolation of the HCVR at the X-axis intersection (when VE=0 l/min)
Time frame: baseline - during the test
Dyspnea
Visual analogic scale (VAS) of dyspnea, from 0 (no dyspnea) to 10 (maximal dyspnea)
Time frame: baseline, end of the test
Plan to share: No
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Centre Hospitalier Universitaire Saint Pierre