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

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)

Conditions

• Pulmonary Disease, Chronic Obstructive
• Lung Diseases, Interstitial
• Chronic Heart Failure
• Pulmonary Arterial Hypertension
• Hyperventilation Syndrome
• Healthy

Interventions

OTHER

simultaneous determination of PaCO2 and PtCO2

Patients in intensive care, equipped, for their routine clinical management, with an arterial catheter blood line, will have a simultaneous determination of PaCO2 and PtCO2: * 1\) at rest; 2 arterial CO2/PtCO2 determinations will be carried out, 10 minutes apart * 2\) During the muscular exercise part of their routine rehabilitation program (whatever it might be, limbs active mobilization, walking, etc...) : several arterial /PtCO2 samples will be collected during the first minutes of their muscular routine: 30 sec, 1 minute, 1 ½ minute, 2, 2 ½ , 3, 4, 5 minutes, 10 minutes (end of exercise). This will generate several couples of blood/transcutaneous CO2 determinations

OTHER

Hyperventilation test

Repeated pairs of PtCO2 and PaCO2 (through arterialized capillary sampling), will be measured at the following timing: rest (0), then 30 sec post beginning of hyperventilation (breathing with accelerated frequency e.g. 30/min), 1 minute, 1 ½ minute 2, 2 ½ , 3, , 4, 5 minutes; recovery of this hyperventilation will be followed, for 5 minutes, with the PtCO2, during 3 minutes

OTHER

Exercise test

an exercise test, according to the routine protocol used in the clinic: initial phase of 3 minutes gentle pedaling (10 to 50 watts, according to subject capabilities), then stepwise increase in the workload, by increments of 20-40 watts every minute, until maximum tolerated workload (VO2max). Repeated pairs of PtCO2 and PaCO2 (through arterialized capillary sampling), will be measured at the following timing: rest -10 minutes, 0, then 30 sec post beginning of exercise, 1 minute, 1 ½ minute 2, 2 ½, 3 minutes, then 3 ½ minutes, then at mid-point of every step increase in workload, until maximum tolerated workload. Recovery will be followed with the PtCO2, for 5 minutes

Sponsors & Collaborators

• Centre Hospitalier Metropole Savoie

  lead OTHER

Study Design

Allocation

NON_RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-02-22

Primary Completion

2024-02-22

Completion

2024-02-22

Countries

• France

Study Locations