Breath Analysis Technique to Diagnose Pulmonary Embolism

April 19, 2022 updated by: Wake Forest University Health Sciences

Expired CO2/O2 Analysis to Diagnose Pulmonary Embolism

A pulmonary embolism (PE) is a blockage in one of the arteries of the lungs, and is usually caused by a traveling blood clot. The D-dimer blood test is currently used to diagnose PEs, but it is not always accurate for individuals who have recently undergone surgery or who have inflammatory-provoking diseases. The purpose of this study is to evaluate the effectiveness of the Carboximeter, a new PE diagnostic device that measures carbon dioxide (CO2) and oxygen (O2) output, in individuals at risk for developing PEs.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

PE is the second leading cause of sudden, unexpected death in the United States. In 90% of the cases, it is caused by deep vein thrombosis: a blood clot forms in a vein, travels through the bloodstream, and lodges in the lungs. PE symptoms vary, and can include cough, shortness of breath, chest pain, rapid breathing, or increased heart rate. Some medical procedures and diseases activate inflammation and blood coagulation, thereby making individuals more vulnerable to PE. Surgery, kidney dialysis, cancer, connective tissue diseases, infectious diseases, and being over 70 years old put individuals at increased risk for developing PEs. A common screening test for PE is the D-dimer blood test, which measures the level of a specific protein that is released following a PE. This test, however, has proven to be an unreliable diagnostic tool for individuals who are at high risk for PE. A more reliable diagnostic tool is needed. The Carboximeter is a new device that measures the ratio of CO2/O2 pressure in an individual's expired breath. By monitoring these components, researchers may be able to accurately diagnose PEs in high risk individuals. The purpose of this study is to evaluate the effectiveness of the Carboximeter at diagnosing PE in individuals at risk for developing PEs.

This study will be conducted in two phases. In Phase I, CO2/O2 ratio and D-dimer levels will be measured prior to and following orthopedic or cancer-related surgery in 100 individuals at risk for developing PEs. In Phase II, the same measurements will be carried out on 350 high risk individuals who are experiencing PE symptoms. These individuals will also undergo computed tomography (CT) angiography and venography, in which blood flow will be visualized using x-rays. A follow-up evaluation will occur 30 days later. If any participant from Phase I or II experiences a PE or a medical condition that affects their lungs, such as asthma or chronic obstructive pulmonary disease (COPD), researchers may schedule a follow-up evaluation to obtain repeat measurements.

Study Type

Interventional

Enrollment (Actual)

475

Phase

  • Phase 2
  • Phase 3

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

  • United States
    • North Carolina
      • Charlotte, North Carolina, United States, 28203
        • Carolinas Medical Center

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 and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Phase I Inclusion Criteria:

  • Experienced or is scheduled for at least one of the following:

    1. Hip or knee replacement surgery
    2. Hip or acetabular fracture surgery
    3. Pelvic fracture
    4. Decompression for spinal stenosis surgery
    5. Scoliosis corrective surgery
    6. Craniotomy surgery for brain tumor
    7. Surgery for any of the following cancers: bladder, colon (including caecum and rectum), kidney, ovary, pancreas, or uterus

Phase I Exclusion Criteria:

  • Currently undergoing treatment for PE or has received treatment for PE in the 4 weeks prior to study entry
  • Hospitalized for fewer than 2 days
  • Anatomic abnormality that would prevent use of a mouthpiece
  • Living situation that makes follow-up difficult (e.g., homeless, incarcerated)

Phase II Inclusion Criteria:

  • Clinical suspicion of PE with signs or symptom suggestive of PE within 24 hours of presentation and at least one risk factor for PE, as defined under the criteria as outlined in this protocol
  • CTA of pulmonary arteries ordered by clinical care providers
  • 18 years or older or an emancipated 17 year old
  • Written informed consent

Phase II Exclusion Criteria:

  • Hemodynamic instability, including patients with a systolic blood pressure less than 90 mm Hg
  • Severe respiratory distress or the inability to breathe room air without the sensation of severe dyspnea
  • Pulse oximetry reading that declines more than 10% when exogenous oxygen is discontinued with accompanying worsening or new dyspnea
  • Intubated
  • Cannot breathe through the mouth owing to anatomic, physical or mental limitation
  • No fixed address, no telephone number, are from out of town or have other reason to suspect difficulty with follow-up
  • Incarceration
  • Known active tuberculosis
  • Prior PE or DVT with history of medical noncompliance with oral anticoagulation therapy based upon a history of unplanned subtherapeutic INR measurements (less than 1.5)
  • Active PE within previous 6 months and currently under treatment with anticoagulation
  • Pregnant
  • Disallowed medications: treatment with any fibrinolytic agent within 48 hours prior to enrollment

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

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: BreathScreen PE + D-dimer
CO2/O2 ratio will be measured using the Breath Screen PE device. D-dimer levels will also be collected.
Device: BreathScreen PE
One minute of breath collection by tidal breathing into the BreathScreen PE and blood draw for D-dimer level

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Phase I: Percentage Change in the Postoperative End Tidal CO2/O2 Ratio and D-dimer Concentration Relative to the Preoperative Measurement
Time Frame: Pre-op measurement: the morning of surgery. Post-op measurement: the latter of postoperative day 3 or hospital discharge
Median postoperative change in end tidal CO2/O2 ratio calculated as 100% * [(postoperative-preoperative)/(preoperative)]
Pre-op measurement: the morning of surgery. Post-op measurement: the latter of postoperative day 3 or hospital discharge
Phase II: Probability of Pulmonary Embolism Diagnosis by D-dimer Alone vs. D-Dimer Plus CO2/O2 for Pulmonary Embolism Diagnosed by CT Scan.
Time Frame: Measured at 45 days
D-dimer > 499 ng/ml, etCO2/O2 < 0.28, Pulmonary Embolism diagnosed by CT scan
Measured at 45 days

Collaborators and Investigators

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

Sponsor

Wake Forest University Health Sciences

Collaborators

National Heart, Lung, and Blood Institute (NHLBI)
WFD Ventures Incorporated

Investigators

  • Principal Investigator: Jefferey A. Kline, MD, Indiana University School of Medicine

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

January 1, 2006

Primary Completion (Actual)

April 1, 2008

Study Completion (Actual)

June 1, 2008

Study Registration Dates

First Submitted

August 24, 2006

First Submitted That Met QC Criteria

August 24, 2006

First Posted (Estimate)

August 29, 2006

Study Record Updates

Last Update Posted (Actual)

April 21, 2022

Last Update Submitted That Met QC Criteria

April 19, 2022

Last Verified

June 1, 2021

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 433
  • R42HL086316-01 (U.S. NIH Grant/Contract)

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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