A Simple Clinical Tool to Help Diagnose Pulmonary Embolism: Phase 1

The goal of this project is to determine if the change in oxygen saturation during deep inspiration ("augmented pulse oximetry") can be used as a method to rule out pulmonary embolism (PE). The investigators propose to evaluate a simple, non-invasive clinical tool to help rule out PE. The investigators plan to measure the oxygen saturation of 40 consecutive patients with newly-diagnosed PE (within 60 minutes of diagnosis) and 80 matched controls who do not have a PE. Trained, blinded Respiratory Therapists or Study Coordinators will record each patient's oxygen saturation before, during, and after a 2-minute period of deep inspirations (vital capacity [the maximal amount of air that can be inhaled, measured in milliliters]) using an incentive spirometer. The investigators' central hypothesis is that persons with a PE will not respond to augmented pulse oximetry and will not significantly improve or normalize their oxygen saturation.

Study Overview

• Status: Completed
• Conditions: Pulmonary Embolism
• Intervention / Treatment: Other: Augmented pulse oximetry using incentive spirometer.; Device: Incentive spirometer.

Detailed Description

Patients will be identified and enrolled by the Mayo Clinic St. Marys Emergency Department staff as they are undergoing medical care in the Emergency Department.

The investigators will calculate the difference in oxygen saturation pre- and post-deep inspiration (ΔSpO2 at 1 minute, 2 minutes and 4 minutes), and then correlate these values with the CT result.

In cases of PE, The investigators expect the SpO2 to remain unchanged, or to change less than 3-5%. The investigators expect alternate hypoxemic conditions to have a significantly greater increase in SpO2.

• Study Type: Interventional
• Enrollment (Actual): 64
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Minnesota
    • Rochester, Minnesota, United States, 55905
      • Mayo Clinic

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• 18 years of age or greater.
• Agrees and able to participate in the study.
• Room air SpO2 (oxygen saturation) less than 92% and newly-diagnosed PE (or controls with no PE) based on CT angiogram result.

Exclusion Criteria:

• Clinical concern for instability.
• Systolic blood pressure less than 100 mm Hg.
• Heart rate ≥140 beats per minute.
• Oxygen saturation less than 85% with more than 4 L supplemental oxygen.
• Unable to participate/comply with instructions for using the incentive spirometer.
• Patients from the Federal Medical Center in Rochester, Minnesota.
• Patients who do not speak English (due to the need for expediency).

Patients will be under the care of the Emergency Department team who have the skills and resources to monitor and treat patients if they were to become unstable.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Proven pulmonary embolism.; Augmented pulse oximetry using incentive spirometer. Emergency Department patients with pulmonary embolism.	Other: Augmented pulse oximetry using incentive spirometer.; Augmented pulse oximetry using incentive spirometer.; Device: Incentive spirometer.; The incentive spirometer is a simple passive device that measures the amount of air a person can inhale.; Other Names: AirLife Volumetric Incentive Spirometer.
Other: Control patients; Augmented pulse oximetry using incentive spirometer. Emergency Department patients who do not have pulmonary embolism.	Other: Augmented pulse oximetry using incentive spirometer.; Augmented pulse oximetry using incentive spirometer.; Device: Incentive spirometer.; The incentive spirometer is a simple passive device that measures the amount of air a person can inhale.; Other Names: AirLife Volumetric Incentive Spirometer.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in oxygen saturation using augmented pulse oximetry for patients with and without pulmonary embolism.	Trained, blinded Respiratory Therapists or Study Coordinators will record each patient's oxygen saturation before, during, and after a 2-minute period of deep inspirations (vital capacity) using an incentive spirometer. The investigators will calculate the difference in oxygen saturation pre- and post-deep inspiration (ΔSpO2 at 1 minute, 2 minutes and 4 minutes), and then correlate these values with the CT result.	Oxygen saturation (SpO2) will be recorded prior to using the spirometer, at 1 minute (during use of the spirometer), at 2 minutes (at the end of using the spirometer), and at 4 minutes.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vital capacity (the maximal amount of air that can be inhaled, measured in milliliters) during augmented pulse oximetry.	The single maximum value obtained before, during, or after use of the incentive spirometer.	The single maximum value obtained prior to using the spirometer, at 1 minute (during use of the spirometer), at 2 minutes (at the end of using the spirometer), and at 4 minutes.

Collaborators and Investigators

• Sponsor: Mayo Clinic
• Investigators: Principal Investigator: A. S. Keller, MD, Mayo Clinic

Publications and helpful links

Helpful Links

• Mayo Clinic Clinical Trials

Study record dates

Study Major Dates

• Study Start: June 1, 2013
• Primary Completion (Actual): November 11, 2024
• Study Completion (Actual): November 11, 2024

Study Registration Dates

• First Submitted: June 28, 2013
• First Submitted That Met QC Criteria: July 10, 2013
• First Posted (Estimated): July 12, 2013

Study Record Updates

• Last Update Posted (Actual): March 28, 2025
• Last Update Submitted That Met QC Criteria: March 25, 2025
• Last Verified: March 1, 2025

More Information

Terms related to this study

• Keywords: emergency department; pulmonary embolism; pulse oximetry; hypoxemia; deep inspiration; clinical diagnosis; change in oxygen saturation; vital capacity
• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Respiratory Tract Diseases; Lung Diseases; Embolism and Thrombosis; Pulmonary Embolism; Embolism
• Other Study ID Numbers: 12-009527

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No