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

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.

Study Overview

• Status: Recruiting
• Conditions: Pulmonary Disease (COPD), Chronic Obstructive
• Intervention / Treatment: Diagnostic test: Capillary blood gas analysis

• Study Type: Interventional
• Enrollment (Estimated): 65
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Nathalie Ducot, MD-PhD; Phone Number: +33 (0)4 92 03 32 42; Email: ducot.n@chu-nice.fr
• Study Contact Backup: Name: Charlotte Monge; Phone Number: +33 (0)7 87 51 25 93; Email: monge.c@chu-nice.fr

Study Locations

• France
  • Nice, France, 06000
    • Recruiting
    • CHU de Nice
    • Contact: Nathalie Ducot, MD-PhD; Phone Number: +33 (0)4 92 03 32 42; Email: ducot.n@chu-nice.fr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Respiratory distress arm requiring a noninvasive ventilation

Diagnostic test: Capillary blood gas analysis; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	Agreement between arterial and capillary pCO₂ measurements, assessed using Bland-Altman analysis with mean bias and the 95% limits of agreement	Baseline (once the patient arrives at the emergency care unit and is included in the study)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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.	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 in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.	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.	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 in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.	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	Baseline (once the patient arrives at the emergency care unit and is included in the study)
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.	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	One hour after initiation of non-invasive ventilation.
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.	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.	One hour after initiation of non-invasive ventilation.
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.	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	One hour after initiation of non-invasive ventilation.
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.	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.	One hour after initiation of non-invasive ventilation.
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.	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	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 in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.	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.	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 in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.	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	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 in patients requiring a non-invasive ventilation due to an exacerbation of COPD or a cardiogenic APE.	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	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 in patients with an exacerbation of COPD or a cardiogenic APE 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	One hour after initiation of non-invasive ventilation.
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.	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	One hour after initiation of non-invasive ventilation.
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.	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	One hour after initiation of non-invasive ventilation.
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.	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	One hour after initiation of non-invasive ventilation.

Collaborators and Investigators

• Sponsor: Centre Hospitalier Universitaire de Nice

Study record dates

Study Major Dates

• Study Start (Actual): September 28, 2026
• Primary Completion (Estimated): March 24, 2027
• Study Completion (Estimated): March 24, 2027

Study Registration Dates

• First Submitted: September 17, 2026
• First Submitted That Met QC Criteria: September 17, 2026
• First Posted (Actual): September 23, 2026

Study Record Updates

• Last Update Posted (Actual): October 2, 2026
• Last Update Submitted That Met QC Criteria: October 1, 2026
• Last Verified: October 1, 2026

More Information

Terms related to this study

• Keywords: COPD; respiratory distress; APE; capillary blood gas analyses; arterial blood gas analyses
• Additional Relevant MeSH Terms: Pathologic Processes; Chronic Disease; Disease Attributes; Respiratory Tract Diseases; Respiration Disorders; Lung Diseases, Obstructive; Signs and Symptoms, Respiratory; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Lung Diseases; Pulmonary Disease, Chronic Obstructive; Dyspnea
• Other Study ID Numbers: 25-PP-13

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No