Non-Invasive Measurement of Cardiac Output and Stroke Volume in PE
Non-Invasive Measurement of Cardiac Output and Stroke Volume in PE
Pulmonary embolism impacts over 1 in 1000 adults annually and is the third leading cause of
 cardiovascular death after heart attack and stroke. The consequence of each PE is widely
 variable. Physiologically, the morbidity and mortality of PE is ultimately caused by failure
 of the right ventricle. The acute rise in pulmonary vascular resistance caused by a PE can
 overwhelm the right ventricle, resulting in a drop in cardiac output and death from failure
 of the heart to provide vital perfusion. Despite the importance of stroke volume and cardiac
 output in the current understanding of PE mortality, they are notably absent from risk
 stratification scores because they historically could only be measured invasively.

 Novel non-invasive methods of estimating stroke volume and associated cardiac output have the
 potential to revolutionize PE risk stratification and care. Non-invasive blood pressure
 (NIBP) monitors can even measure stroke volume beat to beat, allowing for continuous
 evaluation of cardiac function. NIBP systems are typically composed of a finger cuff with an
 inflatable bladder, pressure sensors, and light sensors. An arterial pulse contour is formed
 using the volume clamp method of blood pressure measurement combined with calibration and
 brachial pressure reconstruction algorithms. The stroke volume with each heart beat can be
 estimated as the area under the systolic portion of the blood pressure curve divided by the
 afterload. NIBP monitors may improve clinical care of PE because they allow for assessment of
 dynamic cardiac changes in real time. Detection of worsening stroke volume in acute PE could
 inform providers of impending cardiac collapse, and improvement of stroke volume may function
 as a positive prognostic factor or marker of therapeutic success. Use of NIBP monitors during
 acute PE to identify clinically significant changes in cardiac function may advance both PE
 prognostication and management.

 Our clinical study proposes to monitor hemodynamic parameters including stroke volume in
 patients with acute pulmonary embolism using non-invasive blood pressure monitors. The
 relationship between hemodynamic parameters and PE outcomes will be assessed, as well as the
 changes in hemodynamic parameters with PE intervention. To our knowledge, interval monitoring
 of stroke volume during acute PE with NIBP monitors has never been reported before.
This is a single center study to evaluate the use of non-invasive measurement of stroke
 volume and cardiac output to assess risk and response to treatment in patients with acute
 pulmonary embolism (PE). A total of 40 subjects at Ronald Reagan UCLA Medical Center are
 anticipated to be enrolled.

 After informed consent is obtained, the following procedure will be performed:

 Patients requiring ICU level care with confirmed diagnosis of PE by CT angiogram or EBUS will
 be connected to a device that measures hemodynamics non-invasively called the Edwards
 ClearSight system and Edwards EV1000 clinical platform for 12 to 24 hours. The device is a
 finger probe worn with a supportive forearm strap. Hemodynamic measurements from the finger
 cuff will be recorded at intervals. After 12 hours, measurements will be taken if patient
 comfort and compliance allows.

 Patients will be followed through their hospitalization. Standard of care data will be
 collected from the medical record including vital signs, cardiac monitor recordings, baseline
 electrocardiogram, central venous pressure (CVP) if available, ventilator settings and
 measurements, labs (troponin, d-dimer, lactate, pH, complete blood count, basic metabolic
 panel, B-type natriuretic peptide (BNP) or N-terminal-pro hormone BNP (NT-proBNP),
 prothrombin time and international normalized ratio (PT/INR), anti-Xa assay, and partial
 thromboplastin time (PTT)), imaging, interventions performed, therapies administered,
 discharge outcome and functional status.

 As this is a study looking at the feasibility of non-invasive measurement of cardiac output
 and stroke volume for treating acute pulmonary embolism, study personnel performing the study
 procedures will not be blinded to the clinical diagnosis and the management of the subject.
Inclusion Criteria:

 -  Patient ≥ 18 years of age.

 -  The patient must understand and sign informed consent form (ICF).

 -  Patients requiring intensive care unit (ICU) level care with a confirmed diagnosis of
 pulmonary embolism (PE) by computed tomography (CT) angiogram or endobronchial
 ultrasound (EBUS) prior to or within 4 hours of initiation of any PE therapy or
 intervention.

 -  If a patient already has non-invasive hemodynamic monitoring by the Edwards system or
 by other systems, such as the Cheetah NICOM system, as part of their standard of care,
 this patient can still be enrolled. If the patient is already being followed by
 another system such as NICOM, the Edwards system would be added to it as long as the
 patient consents.

 Exclusion Criteria:

 -  BMI < 20 or BMI > 35.

 -  Height less than 120 cm.

 -  Diagnosis of atrial fibrillation, moderate to severe aortic or mitral valve
 insufficiency or stenosis, scleroderma, or end-stage renal disease.

 -  Patients on extracorporeal membrane oxygenation (ECMO).