Workflow and Framework for Collecting and Implementing Point-of-Care Ultrasound Data in the Management of Heart Failure Patients
Summary
This protocol presents a scalable workflow for the use of point-of-care ultrasound in the management of hospitalized and outpatient heart failure patients.
Abstract
Management and prevention of acute decompensated heart failure remain highly prevalent and challenging medical conditions. Incorporation of Point-of-Care Ultrasound (POCUS) as an adjunctive tool for assessing volume status and treatment response has shown significant promise. POCUS can be used for imaging internal anatomic structures serially and capturing these images for comparison and measurement over time. This protocol describes a scalable and standardized methodology for the serial assessment of the inferior vena cava (IVC). The methodology includes serial image collection, measurement, and presentation in the electronic medical record. A workflow for POCUS-acquired images of the IVC was created to capture the images and measure the diameter in a discrete data field for direct comparison over time and in response to clinical management. The protocol also includes the assessment of the presence or absence of pleural effusion as discrete data in the standardized workflow. By integrating POCUS into heart failure management, clinicians can improve patient outcomes through more precise and timely adjustments in treatment.
Introduction
Point-of-care ultrasound (POCUS) is an emerging technology that can be used in day-to-day clinical settings. Although commercially available hand-carried ultrasound devices have been marketed for over 13 years, regular use outside of bedside procedures has been limited1. POCUS offers an intuitive application in the acute care setting for the diagnosis of specific disease states like cardiac arrest, congestive heart failure, identification of pneumothorax, assessment of pericardial effusion, and detection of free intra-abdominal fluid in trauma or surgery patients2. POCUS is well established as an evidence-based tool in assessing patients for the diagnosis of heart failure3. However, the implementation of POCUS using serial assessment in response to therapy is less well-established4.
POCUS-guided heart failure management includes the visual assessment of central venous pressure (CVP) and right atrial pressure by observing the diameter and collapsibility of the inferior vena cava (IVC). Additionally, POCUS can be used to observe the presence of pleural effusions and anatomical changes that correlate with physiological changes during treatment, including biventricular cardiac function, heart rate, contractility, mitral valve regurgitation, and acute changes in clinical status not self-evident with physical examination5.
In 2011, the clinical practice group began incorporating POCUS into the routine physical examination for all face-to-face inpatient and outpatient encounters (approximately 40,000). Anecdotal observations of anatomical changes visualized by POCUS often seemed to correspond with clinical events and biomarker measurements6 (Figure 1).
In the study institution, beginning in 2015, a discrete data field was built within the electronic health record to track the diameter and compressibility of the inferior vena cava (IVC). A binary data field was also created to document the presence or absence of pleural effusions identified with POCUS. In over seven years of patient care with the incorporation of POCUS in the clinical management of hospitalized heart failure patients, the acquisition and incorporation of POCUS data and IVC measurements have been recorded for more than 6,000 encounters. From an experiential perspective, the clinical practice group found the use of POCUS valuable in assisting with optimizing medical management and refining guideline-directed medical therapy, thereby personalizing the care of heart failure patients.
In this study, a POCUS exam was conducted using a phased-array hand-carried ultrasound device with a digital display screen. Images of the inferior vena cava (IVC) were obtained by scanning the patient through the subcostal acoustic window7 (Figure 2). The IVC images were acquired and measured on the digital display, specifically at a level caudal to the middle hepatic vein. Live images were paused, and a frame-by-frame image scroll on the device was utilized to identify and measure the maximal IVC diameter during the cardiac and respiratory cycle. The measurement was recorded in a data flowsheet within the patient's electronic medical record, and a screenshot of the measured image was uploaded into the patient chart to document the location and angle of measurement acquisition. Subsequently, the measurement flowsheet and uploaded image were added to the patient's progress note.
Protocol
Representative Results
Discussion
A valuable contribution of this publication lies in presenting a scalable clinical workflow that incorporates bedside-acquired dynamic anatomical measurements (the IVC), which correlate with and respond to physiological changes. Changes in CVP are correlated with alterations in IVC measurements. These anatomical changes occur in response to treatment and often correlate with symptoms in patients diagnosed with heart failure5,7,8. Guidelines describing IVC diameter measurements and the corresponding right atrial pressure values in mmHg are outlined in a standards publication from the American Society of Echocardiography9.
Optimizing care for hospitalized heart failure patients is guided by treatment aimed at achieving euvolemia10. POCUS serves as a clinical tool providing a validated assessment of CVP, which dynamically changes with alterations in volume status5. The use of POCUS in clinical management of heart failure patients aims to assist in guiding optimal medical therapy, with the goal of directing patient care toward achieving and maintaining clinical euvolemia. Furthermore, longitudinal care of heart failure patients guided by POCUS can help keep patients closer to or within a narrower therapeutic window, aiming for long-term sustained euvolemia (Figure 4).
Creating workflows to standardize, personalize, and optimize the acquisition and use of POCUS as a clinical tool in managing CHF has broad and impactful implications for how patients receive care. The clinical team has developed a scalable workflow that can be implemented by various members of the clinical care team, including nurses, sonographers, clinical pharmacists, advanced practice providers, and physicians (Figure 5). This POCUS-guided protocol for managing heart failure offers practitioners using the standardized workflow opportunities for iterative improvement in POCUS acquisition skills, which can translate to an enhanced ability to acquire images of other anatomical regions. This streamlined and scalable workflow may serve as a pathway to broader utilization of POCUS in other clinical areas and foster the development of innovative applications in both acute and chronic disease management.
Lung POCUS is an emerging and, in some settings, a common method for assessing lung water and, by association, lung congestion. B-lines, also known as comet tails, are reverberation artifacts originating from the lung pleural interface11. In acute decompensated heart failure patients, B-lines may be observed in the emergency department12. Challenges associated with lung ultrasound include the necessity for multiple anatomical assessments on each patient (4-8 lung imaging windows per lung POCUS exam), the time required to acquire these multiple lung POCUS images, the subjectivity and variability of imaging influenced by clinician operators and patient positioning, and the difficulty in longitudinally comparing and assessing treatment responses. Furthermore, there is a lack of empirical physiological measurements correlating with the presence, absence, or density of lung B-lines. Additionally, while POCUS-identified B-lines are indicative of pulmonary congestion, they are not specific to this condition and can also be observed in COVID-19 pneumonia and various acute and chronic pulmonary infectious and inflammatory conditions13.
There are still limitations to the proposed workflow. Participants need to develop proficiency in POCUS imaging of the IVC and adhere to a standardized protocol for the location and timing of IVC measurements during the respiratory cycle. The clinical practice proposed aims to identify the maximal IVC diameter during end expiration, specifically caudal to the middle hepatic vein. However, a challenge lies in the variability of this anatomy among patients14. To address this variability, the workflow includes an image capture and measurement protocol that enables serial comparison of IVC measurements within each patient over time. This approach facilitates monitoring and may mitigate the impact of anatomical differences between individuals.
The expansion of a POCUS protocol in the management of heart failure patients beyond traditional healthcare settings holds promise for delivering more precise and personalized care. Implementing standardized POCUS workflows for heart failure management not only allows for more thorough patient evaluation but also benefits individuals who face barriers to accessing conventional healthcare settings. This includes patients residing in remote areas, those with limited mobility or transportation options, and individuals with constrained resources for healthcare services15. Moreover, integrating clinical tools like POCUS presents opportunities for closely monitoring symptomatic CHF patients in ambulatory settings, potentially reducing reliance on inpatient hospital resources. This model not only enhances patient care but also optimizes resource allocation in healthcare delivery.
Potential future research could involve a prospective observational cohort study to accurately assess the value of POCUS in managing heart failure patients. Such a study could involve matching a POCUS-directed heart failure management group with a standard care heart failure treatment group to evaluate outcomes comprehensively. Given the expanding use of POCUS in clinical settings, a prospective evaluation of its efficacy and impact is crucial.
Furthermore, addressing inter-user variability in the acquisition and interpretation of IVC diameter and collapsibility with POCUS is essential. Variability in both congenital and acquired anatomical features of the IVC can pose challenges in accurately assessing its borders and dimensions, as well as its collapsibility14. These challenges may complicate the standardized assessment and longitudinal measurement of the IVC in clinical practice. Research aimed at understanding and mitigating these challenges could enhance the reliability and utility of POCUS measurements as a standardized clinical tool in heart failure management.
As POCUS becomes increasingly integrated into the clinical care of heart failure patients, workflows and protocols for personalized application will evolve and expand. The study group’s demonstration of collecting and utilizing large volumes of POCUS data in daily clinical practice shows promise for further expansion and refinement. Future research will be crucial for refining methods of acquiring POCUS data and optimizing its use in managing heart failure patients, particularly in achieving tighter control of volume status. Longitudinal management and assessing transitions of care-from hospitalization to ambulatory settings-carry significant implications at a population level. Understanding how POCUS data can support these processes will be essential for enhancing patient outcomes and optimizing healthcare resource utilization.
Divulgazioni
The authors have nothing to disclose.
Acknowledgements
Cedars-Sinai Hospital Honest Enterprise Research Broker (HERB) Committee, Los Angeles, California, USA.
Materials
| Aquasonic Ultrasound Gel 100 | Parker | ECO #20-0299 | The company and the catalog number is one example |
| Epic Electronic Health Record | Epic | The company and the catalog number is one example | |
| GE Vscan Extend | General Electric | 5721203-100 Rev.13 | Broad-bandwidth linear array: 3.3-8.0 MHz |
| Haiku | Epic | 10.3 | The company and the catalog number is one example |
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