Clinical trial NCT01898637: A Simple Clinical Tool to Help Diagnose Pulmonary Embolism: Phase 1
Official title: A Simple Clinical Tool to Help Diagnose Pulmonary Embolism: Phase 1
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Pulmonary Embolism
Keywords: pulmonary embolism
pulse oximetry
change in oxygen saturation
hypoxemia
emergency department
deep inspiration
vital capacity
clinical diagnosis
Lead sponsor: Mayo Clinic
Sponsor class: OTHER
First posted: 2013-07-12
Enrollment: 64
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: PARALLEL
Primary purpose: DIAGNOSTIC

Brief summary: 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.

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Change in oxygen saturation using augmented pulse oximetry for patients with and without pulmonary embolism.
timeFrame: 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 outcomes:
measure: Vital capacity (the maximal amount of air that can be inhaled, measured in milliliters) during augmented pulse oximetry.
timeFrame: 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.
Other outcomes:
Locations:
city: Rochester
country: United States
facility: Mayo Clinic
state: Minnesota
Study officials:
affiliation: Mayo Clinic
name: A. S. Keller, MD
role: PRINCIPAL_INVESTIGATOR
References: