Assessment of Continuous Measurement of Transcutaneous CO2 for Evaluation of Alveolar Dead Space During Exercise

Not Applicable

• Conditions: Pulmonary Arterial Hypertension; Hyperventilation Syndrome; Pulmonary Disease, Chronic Obstructive; Lung Diseases, Interstitial; Chronic Heart Failure; Healthy
• Interventions: Other: simultaneous determination of PaCO2 and PtCO2; Other: Hyperventilation test; Other: Exercise test

• Registration Number: NCT03718780
• Lead Sponsor: Centre Hospitalier Metropole Savoie

Brief Summary

The study aim is to monitor, during exercise tests carried out in various conditions, the alveolar dead space, by means of continuous transcutaneous measurement of Pt CO2, which would be used as a surrogate for arterial PaCO2. Validity of this measurement needs to be assessed against arterial sampling (either arterial, or arterialized capillary), especially with regards to the lag time required by the CO2 diffusion from the arterial compartment (PaCO2) to the cutaneous one (PtCO2), in particular when rapid changes of CO2 might be induced by exercise.

The evaluation will be done in 2 different settings:

* intensive care patients, equipped, for their routine clinical care, with an arterial line; this allows for a precise timed comparison between PaCO2 and PtCO2 readouts;

* routine exercise test, where blood gas evaluation is done essentially by means of arterialized earlobe capillary sampling.

Following assessment of validity of the measurement (and the lag time PaCO2-PtCO2 which might be necessary to introduce as a correction), evolution of dead space during excise test will be tested in different conditions: Healthy subjects, patients with Chronic Obstructive Pulmonary Disease (COPD), chronic heart failure (CHF), hyperventilation, Pulmonary artery hypertension (PAH), or interstitial lung disease (ILD)

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2018-10-04
• Study First Submitted QC: 2018-10-23
• Study First Posted: 2018-10-24
• Study Start: 2019-02-22
• Status Verified: 2022-06
• Last Update Submitted: 2022-06-13
• Last Update Posted: 2022-06-14
• Primary Completion: 2024-02-22
• Study Completion: 2024-02-22

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 105

Inclusion Criteria

• Written and informed consent, and assent where required.
• Either:

Patients in intensive care, conscious and in stable hemodynamic condition, who are already equipped with an arterial line for blood gas analysis (as required by the routine practice in intensive care; no arterial line shall be inserted for the purpose of this study) (Part A1)

Or patients/subjects scheduled for routine cardio-pulmonary exercise testing. Among these, the following patients will be included: COPD, PAH, healthy subjects, hyperventilation, chronic cardiac failure, interstitial lung diseases (ILD) (Part A2 and Part B)

Exclusion Criteria

• Non-French speaking patients/subjects
• Unstable hemodynamics
• Local cutaneous lesion or infection
• Arterial disease such as fistula
• Women with the following condition: pregnancy, breast feeding
• Persons deprived of liberty (according to article L1121-5 to L1121-8 of the French Public Health Code)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
A1: Patient in intensive care	simultaneous determination of PaCO2 and PtCO2	Patient in intensive care (n=10): in patients in the intensive care unit of the Centre Hospitalier Metropole Savoie (Chambéry, France), where repeated arterial blood gas analysis is routinely performed (Patients equipped for their usual care with an arterial catheter, enabling repeated arterial blood gas determination ). PaCO2 and Pt CO2 will be measured simultaneously at rest, and during conditions inducing PaCO2 modifications (ventilator settings modifications, or exercise as per routine rehabilitation) Comparison will be done between arterial PaCO2 and PtCO2
A2: Healthy subjects	Exercise test	Healthy subjects performing a voluntary hyperventilation, in the laboratory room where routine exercise testing is usually done. Comparison will be done between arterialized PaCO2 and PtCO2, at rest, and during an induced voluntary hyperventilation.
B1: Healthy subject	Exercise test	Subjects, referred for exercise diagnostic testing, and whose results indicate normal cardiac and pulmonary exercise physiology. Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.
A2: Healthy subjects	Hyperventilation test	Healthy subjects performing a voluntary hyperventilation, in the laboratory room where routine exercise testing is usually done. Comparison will be done between arterialized PaCO2 and PtCO2, at rest, and during an induced voluntary hyperventilation.
B4: Chronic heart failure (CHF)	Exercise test	Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.
B5: Pulmonary Arterial Hypertension (PAH)	Exercise test	Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.
B2: Chronic Obstructive Pulmonary Disease	Exercise test	Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.
B3: Interstitial Lung Disease (ILD)	Exercise test	Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.
B6: inappropriate hyperventilation syndrome	Exercise test	Measurement, throughout these exercise tests, of the alveolar dead space, and its kinetics, up to peak VO2, then during recovery, in the different conditions listed above. Alveolar dead space will be calculated using the continuous Pt CO2 values observed, and also with some intermittent PaCO2 measurement, done as per routine modus operandi (arterialized earlobe capillary drawn at rest, at ventilatory threshold, and at peak exercise). The values measured through PtCO2 and PaCO2 will be compared at these 3 time points.

Primary Outcome Measures

Name	Time	Method
Change from baseline of Pt CO2 (transcutaneous CO2 partial pressure) measurement together with PaCO2 (arterial partial CO2 pressure)	at rest and during exercise/hyperventilation: 30 secondes, 1 minute, 1 ½ minute 2, 2 ½ , 3 , 4, 5 and 10 minutes.	Part A: serial simultaneous measurements of Pt CO2 (transcutaneous CO2 partial pressure), and PaCO2 (arterial partial CO2 pressure), done; 1. during exercise; 2. during voluntary hyperventilation
Change from baseline by means of continuous measurement of alveolar dead space (VD/VT=(PaCO2-PECO2) /PaCO2), expressed as a percentage from 0% to 100 %) , during exercise test, in different clinical settings	continuous measurement: from rest throughout exercise test ( beginning of test, to maximum load (5-10 minutes), then throughout 5 minutes recovery.	Part B: change from baseline with continuous alveolar dead space ( (VD/VT=(PaCO2-PECO2) /PaCO2), expressed as percentage from 0 to 100%) variation measurement, during exercise and recovery, in: * healthy subject; * different patient categories: COPD at different stages, pulmonary artery hypertension, hyperventilation syndrome, cardiac failure, Interstitial Lung Disease). Establish patterns seen in these different conditions.

Trial Locations

Locations (4)

Service de pneumologie; 🇫🇷 Béthune, France

Service de pneumologie CHMS; 🇫🇷 Chambéry, France

Service de réanimation médicale - CHMS; 🇫🇷 Chambéry, France

Service de Pneumologie CHU Grenoble; 🇫🇷 La Tronche, France