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NCT Number: NCT07835945

Comparison of Arterial and Capillary Blood Gas Analyses in Patients With Respiratory Distress Due to COPD or APE

The assessment of gas exchange is crucial for the management of patients suffering from respiratory distress due to an exacerbation of chronic obstructive pulmonary disease (COPD) or cardiogenic acute pulmonary edema (APE). These measurements are used by physicians to determine the need for noninvasive ventilation (NIV) as well as to evaluate its effectiveness and to decide whether to continue the treatment.

Arterial blood gas analysis is currently the gold standard for the measurement of these gas exchanges, though invasive, painful and risky (failure risks and possible local complications). Capillary blood gas analysis, which consists in collecting a blood drop from the ear or the finger by capillarity after punction, could represent a less invasive alternative. However, data comparing the performances of arterial and capillary blood gas analysis in the context of respiratory distress requiring a NIV remain limited.

This study is based on the hypothesis that capillary blood gas analysis can perform as well as arterial blood gas analysis. It is aimed at comparing values obtained from arterial and capillary blood gas analyses from patients with respiratory distress and requiring a NIV due to an exacerbation of COPD or cardiogenic APE.

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Key information

Conditions

Pulmonary Disease (COPD), Chronic Obstructive Chronic Disease Disease Attributes Dyspnea Lung Diseases Lung Diseases, Obstructive Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Disease, Chronic Obstructive Respiration Disorders Respiratory Tract Diseases Signs and Symptoms Signs and Symptoms, Respiratory

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients older than 18 years old
  • Patients admitted in the emergency care unit with an exacerbation of COPD or a cardiogenic APE requiring a non-invasive ventilation (i.e. for COPD patients pH< 7.35, for APE patients: PCO2 > 45 mmHg)
  • Patients affiliated to a social security system

Exclusion criteria

  • Patients for which a non-invasive ventilation was initiated upon pre-hospital care
  • Contraindication for non-invasive ventilation
  • Patients for which non-invasive ventilation is not indicated
  • Patients for which capillary or arterial blood gas analyses are impossible
  • Adults subject to legal guardianship (guardianship, conservatorship)
  • Pregnant women
  • Patients with a congenital heart disease

Treatment and study plan

Capillary blood gas analysis

Diagnostic Test

The intervention consists in carrying out arterial, veinous and capillary blood gas analyses before submitting the patient to noninvasive ventilation (5 minutes will separate each sampling). Data from these samplings will be recorded. 1 hour after the implementation of the noninvasive ventilation, patients will once again undergo arterial, veinous and capillary samplings for blood gas analyses. Respiratory parameters will be recorded as well at the onset of the noninvasive ventilation and one hour after its start.

Primary outcomes

  1. Agreement between carbon dioxide pressure (PCO2) values obtained from capillary and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study)

    Agreement between arterial and capillary pCO₂ measurements, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

Secondary outcomes

  1. Agreement between pH values obtained from capillary and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study)

    Agreement between pH values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement.

  2. Agreement between bicarbonate concentration values obtained from capillary and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study)

    Agreement between bicarbonate concentration values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement.

  3. Agreement between base concentration values obtained from capillary and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study)

    Agreement between base concentration values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  4. Agreement between PCO2 values obtained from capillary and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between PCO2 values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  5. Agreement between pH values obtained from capillary and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between pH values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement.

  6. Agreement between bicarbonate concentration values obtained from capillary and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between bicarbonate concentration values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  7. Agreement between base concentration values obtained from capillary and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between base concentration values obtained from capillary and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement.

  8. Agreement between PCO2 values obtained from veinous and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study).

    Agreement between PCO2 values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  9. Agreement between pH values obtained from veinous and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study).

    Agreement between pH values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement.

  10. Agreement between bicarbonate concentration values obtained from veinous and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study).

    Agreement between bicarbonate concentration values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  11. Agreement between base concentration values obtained from veinous and arterial blood gas analyses in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.

    Time frame: Baseline (once the patient arrives at the emergency care unit and is included in the study).

    Agreement between base concentration values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  12. Agreement between PCO2 values obtained from veinous and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between PCO2 values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  13. Agreement between pH values obtained from veinous and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between pH values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  14. Agreement between bicarbonate concentration values obtained from veinous and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between Bicarbonate concentration values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

  15. Agreement between base concentration values obtained from veinous and arterial blood gas analyses in patients with an exacerbation of COPD or a cardiogenic APE one hour after initiation of non-invasive ventilation.

    Time frame: One hour after initiation of non-invasive ventilation.

    Agreement between base concentration values obtained from veinous and arterial blood gas analyses, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement

Study contacts

Contact information is provided by the study sponsor or research team.

Charlotte Monge

CONTACT

[email protected]

+33 (0)7 87 51 25 93

Nathalie Ducot, MD-PhD

CONTACT

[email protected]

+33 (0)4 92 03 32 42

Sponsors and collaborators

Lead sponsor

Centre Hospitalier Universitaire de Nice

Other

Registry information

Acronym: GAZOCAP

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Sep 23, 2026
Registry last updated
Sep 23, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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