Intrinsic Periodic Pattern of Breathing (PERHYP1)

July 24, 2014 updated by: Pr. Jean Paul RICHALET, Association pour la Recherche en Physiologie de l'Environnement

Study of Periodic Breathing in Healthy Humans

We made a fortuitous observation of periodic breathing in a healthy subject coming to our outpatient mountain medicine consultation at Avicenne hospital in Bobigny (France). During this consultation, subjects perform a hypoxia exercise test, which allows a good prediction of their risk factors for severe high altitude illnesses. Surprisingly, breath-by-breath recording of the ventilation signal showed a periodic breathing pattern, which increased when the subject started to exercise in hypoxic conditions and was maintained during normoxic exercise.

Therefore, our objective was to confirm this observation in a retrospective study led in 82 subjects who passed this test. We tested the hypothesis that subjects with a brisk ventilatory response to hypoxia might show a more pronounced periodic pattern of ventilation, due to a higher gain of the chemoreceptor feedback loop. Then, our objective is to investigate the mechanisms involved in the periodic pattern in healthy subjects, as a function of exercise intensity, altitude intensity, role of peripheral and central chemoreceptors to O2 and CO2. Finally, we want to investigate the possible role of this ventilatory instability in patients with obstructive or central apneas.

Study Overview

Status

Unknown

Conditions

Detailed Description

In a preliminary study, among the population coming to the outpatient consultation of mountain medicine at Avicenne hospital in 2012, 82 subjects (38 females and 44 males) were randomly selected and separated in two groups of 41 high and 41 low responders to hypoxia according to the median value of the hypoxic ventilatory response to hypoxia at exercise (HVRe > or < 0.84 L/min/kg) derived from the hypoxic exercise test (inspired fraction of O2: 0.115, exercise intensity of 30% of maximal aerobic power), as previously described.

The hypoxic exercise test consists in 4 successive phases of 3 to 4 minutes each with the following sequence: rest in normoxia (RN), rest in hypoxia (RH), exercise in hypoxia (EH) and exercise in normoxia (EN). Minute ventilation ( E, L.min-1) is measured through a metabograph (Vmax Encore, SensorMedics, Yorba Linda, CA). Pulse O2 saturation (SpO2, %) is measured by transcutaneous oximetry (Nellcor N-595, Nellcor, Pleasanton, CA) on a pre-warmed ear lobe. End tidal PCO2 (PETCO2) is measured by infrared thermopile (Vmax Encore, SensorMedics, Yorba Linda, CA). During the whole test, VE, SpO2 and PETCO2 were recorded breath-by-breath. Continuous blood pressure is measured by a Finapres system. Data are transferred to a computer for further spectrum analysis. A Fast Fourier Transform (FFT) is then applied to the ventilation signal in sequences of 128 points in each phase of the test. This method will allow us to detect the presence of peaks in the frequency domain of the ventilation signal. Two main parameters are derived from the FFT: the frequency in hertz (or period in seconds) of the larger peak and its power estimated as the area under the peak at ± 0.02 Hz around the peak (in L2.s-2).

The main study will be designed in order to unravel the mechanisms and role of these oscillations in ventilation. An overall population of 90 healthy subjects and 30 patients will be included in the study.

Step 1. Effect of exercise intensity.

Step 2. Effect of altitude level.

Step 3. Effect of the stimulation of central chemoreceptors by acetazolamide.

Step 4. Effect of inhibiting the peripheral chemoreceptors by hyperoxia.

Step 5. Effect of inhibiting the peripheral chemoreceptors by hyperoxia and stimulating the central chemoreceptors by hypercapnia.

Step 6. Evaluating the presence of these oscillations in patients with sleep apneas.

Step 7. Evaluating the presence of these oscillations in patients with cardiac failure.

Study Type

Observational

Enrollment (Anticipated)

120

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
      • Bobigny, France, 93009
        • Physiology Department

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 65 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Healthy subjects Patients with obstructive sleep apneas Patients with cardiac failure

Description

Inclusion Criteria:

  • depending on the group: see definition of groups

Exclusion Criteria:

  • BMI > 30
  • history of severe cardiac arrhythmia
  • pulmonary hypertension
  • history of coronary disease

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Healthy subjects
male, aged 18-65 moderately trained healthy, no treatment
obstructive sleep apneas
patients with apnea/hypopnea index > 15 BMI < 30 Age < 50 yrs
cardiac failure
NYHA class I to III ejection fraction < 40% age < 65 yrs BMI < 30

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Periodic pattern of ventilation
Time Frame: The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia),
Presence of oscillation in the ventilation signal
The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia),

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Oscillations in heart rate
Time Frame: The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia)
Presence of oscillations in the beat-by-beat ECG signal with a specific peak in the frequency spectrum
The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia)
Oscillations in arterial blood pressure
Time Frame: The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia)
Presence of oscillations in the systolic/diastolic value of instant arterial blood pressure, measured non-invasively.
The measure is made at the end of the 6-min exercise period, only once in each condition (normoxia, hypoxia, hyperoxia, hypercapnia)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Association pour la Recherche en Physiologie de l'Environnement

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 2014

Primary Completion (Anticipated)

June 1, 2015

Study Completion (Anticipated)

December 1, 2015

Study Registration Dates

First Submitted

January 22, 2014

First Submitted That Met QC Criteria

July 24, 2014

First Posted (Estimate)

July 28, 2014

Study Record Updates

Last Update Posted (Estimate)

July 28, 2014

Last Update Submitted That Met QC Criteria

July 24, 2014

Last Verified

July 1, 2014

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • PERHYP1

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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