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Self-care is key to the daily management of chronic heart failure (HF). After discharge from hospital, patients may struggle to recognize and respond to worsening HF symptoms. Failure to monitor and respond to HF symptoms may lead to unnecessary hospitalizations.
This study aimed to (1) determine the feasibility of lung impedance measurements and a symptom diary to monitor HF symptoms daily at home for 30 days following hospital discharge and (2) determine daily changes in HF symptoms of pulmonary edema, lung impedance measurements, and if self-care behavior improves over time when patients use these self-care monitoring tools.
This study used a prospective longitudinal design including patients from cardiology wards in 2 university hospitals—one in Norway and one in Lithuania. Data on HF symptoms and pulmonary edema were collected from 10 participants (mean age 64.5 years; 90% (9/10) male) with severe HF (New York Heart Association classes III and IV) who were discharged home after being hospitalized for an HF condition. HF symptoms were self-reported using the Memorial Symptom Assessment Scale for Heart Failure. Pulmonary edema was measured by participants using a noninvasive lung impedance monitor, the CardioSet Edema Guard Monitor. Informal caregivers aided the participants with the noninvasive measurements.
The prevalence and burden of shortness of breath varied from participants experiencing them daily to never, whereas lung impedance measurements varied for individual participants and the group participants, as a whole. Self-care behavior score improved significantly (
Noninvasive measurement of lung impedance daily and the use of a symptom diary were feasible at home for 30 days in HF patients. Self-care behavior significantly improved after 30 days of using a symptom diary and measuring lung impedance at home. Further research is needed to determine if daily self-care monitoring of HF signs and symptoms, combined with daily lung impedance measurements, may reduce hospital readmissions.
Self-care is recognized as an important aspect of daily management of heart failure (HF) and recommended in international guidelines [
The 5 most characteristic HF symptoms of fluid retention are shortness of breath, shortness of breath when supine, shortness of breath that awakens the patient during sleep, feeling tired, and ankle swelling [
Another promising method for self-monitoring is using noninvasive lung impedance devices to measure pulmonary congestion before HF symptoms are recognized by the patient [
Knowledge is lacking for self-care approaches that combine the use of a self-reported symptom diary with noninvasive lung impedance measurements. The aim of this study was, therefore, to assess patients’ HF symptoms, lung impedance, and self-care behavior at home for 30 days after hospital discharge. This study sought answers to the following research questions:
1. How feasible is it for patients with HF and their caregivers to measure symptoms and signs daily at home using a diary and a noninvasive device for measuring lung impedance during a 30-day period after discharge from hospital?
2. How do daily HF symptoms and lung impedance change during the 30-day assessment period?
3. How does self-care behavior change when patients use a symptom diary and a noninvasive device to measure lung impedance during the assessment period?
This longitudinal observational design study was conducted from May 2017 to November 2017 using eligible patients discharged from cardiology wards in 2 university hospitals in Norway and Lithuania. Norway is a high-income country ranked as number 28 by the World Bank, and Lithuania is ranked as number 84 [
Patients were eligible if they were hospitalized with a primary diagnosis of HF, aged older than 18 years, fluent in Norwegian or Lithuanian, and possessed sufficient cognitive abilities to understand and complete the study protocol. Cognitive abilities were judged by the nurses or cardiologists at the hospital ward. Only patients with New York Heart Association (NYHA) Functional Classification III and IV were included in the study.
Patients with severe HF in need of surgical intervention, advanced chronic kidney disease defined as estimated glomerular filtration rate less than 25 mL per min per 1.73 m2 [
The symptom diary comprised 3 components (
Data collection instruments administered at discharge, at home or at the outpatient clinic.
Data collection instruments | Discharge | Home for 30 days | Outpatient clinic | ||||
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Memorial Symptom Assessment Scale-Heart Failure | —a | xb | — | |||
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Lung impedance | — | x | — | |||
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Medication on demand | — | x | — | |||
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European Heart Failure Self-care Behavior Scale | x | — | x | |||
Clinical examination | x | — | x |
aNot applicable.
bThe x indicates the time and place of data collection.
Candidate participants were identified by cardiologists at the hospital wards. Before discharge, the included participants were instructed on how to use the printed symptom diary, which consisted of spaces to rate symptoms and to write down lung impedance measurements and on-demand medications. Participants and informal caregivers were trained at their home on how to perform lung impedance measurements and about sending the measurements by SMS text messages to a study mobile phone used by the HF study nurse. The HF study nurse was contacted if the participant had problems with bad electrode connections or other technical problems (for example, difficulty sending SMS data from home). Study participants and informal caregivers were instructed on how to recognize HF symptoms and signs through the use of a paper handout with textual explanations, color-coded information related to HF condition, and prominent contact information.
Participants rated their symptoms using an adapted version of the Memorial Symptom Assessment Scale-Heart Failure (MSAS-HF) [
The participants and informal caregivers measured lung impedance at home daily using a CardioSet Edema Guard Monitor (Model 0001; CardioSet Medical, Ltd), a noninvasive impedance monitor developed to measure pulmonary congestion or edema in HF patients [
Measurement of noninvasive lung impedance at home and sending impedance data to the study center by SMS. Schematic illustration shows the correct placement of the 6 Edema Guard Monitor electrodes on an HF patient, measurement of impedance, and how daily measurement data are sent by mobile phone (SMS).
On-demand medication was prescribed, for example, additional diuretics for some of the included participants to be used at home if necessary. Every day, these HF patients recorded their use of any of these on-demand medications in their diary.
The European Heart Failure Self-care Behavior Scale (EHFScBS) is a self-rating instrument that measures HF-related self-care. It comprises 9 items that are self-scored on a 5-point Likert scale. A standardized score ranges from 0 to 100 results, with higher scores indicating better HF self-care [
A standard clinical examination was performed at hospital discharge and at the outpatient clinic 30 days later (
EpiData Entry (EpiData Software, 2017) was used for entering and managing data to optimize data accuracy and entry across the 2 countries. This step is in line with recommendation from the data protection managers at both university hospital sites. Raw data were converted from the EpiData Entry format to the SPSS format for analysis. Variables were either categorical or continuous and were presented as counts, percentages, means and SDs, or median and IQRs. Missing data from the symptom diary were not included in the analysis [
The study was conducted in accordance with the Declaration of Helsinki. Ethical approval was obtained from Regional Committees for Medical and Health Research Ethics in Norway (REC number: 2014/1890) and Vilnius Regional Ethics Committee in Lithuania (approval number: 158200-15-766-280). All participants received verbal and written information about the purpose of the study, signed a written informed consent form before participation, and were free to withdraw from the study at any time. The daily lung impedance measurements were securely sent to the HF study nurse in each country using dedicated study mobile phones. Exchanged study data between the 2 university hospital study sites were deidentified with files encrypted in an email, which required a separate SMS code to be opened. This privacy assurance of research subject data and identity is in accordance with requirements of the data protection officer at the university hospital study sites.
The Edema Guard Monitor lung impedance measuring devices were purchased from the company CardioSet Medical Ltd, Matan, Israel, and researchers and the company signed a written contract with no obligations to the company.
A total of 10 participants with HF in NYHA classes III and IV at inclusion (5 from each country) were recruited. The participants’ mean age was 64.5 years, 8 participants had comorbidities, 1 participant was female, and most of the participants lived with their spouse or children (
Participants’ demographics and clinical characteristics when discharged and 30 days later at the outpatient clinic (N=10).
Characteristics of participants | Discharge | Outpatient clinic | |||
Age (years), mean (range) | 64.5 (37-85) | —a | |||
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Male | 9 | — | ||
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Less than high school | 1 | — | ||
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Spouse | 7 | — | ||
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Grown children | 2 | — | ||
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Nurse | 1 | — | ||
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Full time | 3 | — | ||
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Retired, disability pension | 7 | — | ||
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Ischemic HF | 7 | — | ||
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Dilated | 3 | — | ||
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HF >1 year | 7 | — | ||
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HF <1 year | 3 | — | ||
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II | 0 | 3 | ||
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III | 8 | 6 | ||
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IV | 2 | 1 | ||
Implantable cardioverter-defibrillator, n | 3 | 3 | |||
Cardiac resynchronization therapy with pacemaker or defibrillation, n | 3 | 3 | |||
Jugular venous pressure, n | 1 | 1 | |||
Ankle swelling, n | 5 | 2 | |||
Systolic BPc (mm Hg), mean (SD) | 113.3 (17.5) | 119.2 (19.7) | |||
Diastolic BP (mm Hg), mean (SD) | 74.7 (13.8) | 77.9 (12.4) | |||
Heart rate, mean (SD) | 76.5 (13.6) | 75.3 (12.0) | |||
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Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers | 9 | 10 | ||
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Beta blockers | 9 | 9 | ||
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Loop diuretics | 10 | 10 | ||
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Thiazides diuretics | 1 | 1 | ||
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Mineralocorticoid antagonist | 7 | 5 | ||
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Ivabradine | 1 | 2 | ||
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Nitrates | 1 | 1 | ||
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No comorbidity | 2 | — | ||
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Low (1-2) | 3 | — | ||
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Medium (3-4) | 5 | — | ||
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Hemoglobin, g/dL (reference: 13.4-17.0) | 14.7 (1.7) | 14.6 (1.1) | ||
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Creatinine, mmol/L (reference: 60-105) | 104.3 (23.7) | 122.2 (59.4) | ||
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N-terminal pro b-type natriuretic peptide, pg/mL | 2200 (1408) | 2910 (2788) | ||
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Estimate of glomerular filtration rate, mL/min/1.73m2 | 66.3 (19.3) | — |
aNumber same at discharge and 30 days later at the outpatient clinic.
bHF: heart failure.
cBP: blood pressure.
Participants used the symptom diary daily, and with support from their caregivers, they measured lung impedance daily. A total of 7 participants were able to provide data for the full 30-day assessment period. For impedance data, 262 of 300 (87%) recorded measurements were successfully made and sent. For the symptom diary, 1332 of 1500 (89%) entries were successfully made. Missing data were mainly from 2 participants who were classified as NYHA class IV. These participants provided diary and lung impedance data for 19 of 30 days (57%) and 22 of 30 days (63%), respectively. These 2 participants had a few missing lung impedance measurements because of issues with poor signal quality presumably related to suboptimal electrode connections, despite performing more than 3 required measurements and receiving advice from the HF study nurse. A third participant did not have home caregiver support for measuring lung impedance after day 26; thus, participation was terminated on day 26 for that participant. Moreover, 2 participants lived alone, but 1 of them moved in with a family member during the 30-day home assessment period. The other participant received support from an HF study nurse every day to apply the electrodes, although the participant performed the measurement.
Prevalence and burden assessment of the 5 symptoms selected from the MSAS-HF varied among the participants (
The total burden score (mean of the frequency, severity, and distress scores) of
A total of 9 participants experienced symptoms indicating fluid accumulation for 1 or more days. They reported feeling
The number of participants experiencing (prevalence) and total burden score (mean of the frequency, severity, and distress scores) of the 5 heart failure symptoms and signs during the 30-day postdischarge assessment period (N=10).
Symptom | Prevalence | Total burden score | ||||||||
None of the days, n | 1 day or more, n | Every day, n | 1 day or more | Every day | ||||||
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Mean (SD) | Minimum | Maximum | Mean (SD) | Minimum | Maximum | ||
Shortness of breath | 3 | 7 | 4 | 2.9 (0.8) | 2.3 | 3.8 | 2.8 (0.5) | 2.3 | 3.4 | |
Difficulty breathing lying flat | 4 | 6 | 1 | 2.4 (1.3) | 1.2 | 4.6 | 2.8(-a) | 2.8 | 2.8 | |
Wake up breathless | 5 | 5 | 1 | 1.6 (0.6) | 1.0 | 2.4 | 2.9 (-) | 2.9 | 2.9 | |
Lack of energy | 2 | 8 | 3 | 2.2 (1.3) | 1.3 | 4.4 | 3.6 (1.1) | 2.6 | 4.8 | |
Swelling of extremities | 7 | 3 | 0 | 1.7 (0.6) | 1.1 | 2.3 | 0 (-) | 0 | 0 |
aOnly 1 participant had the symptom every day.
At hospital discharge, individual ΔLIRs ranged from −20.9% to −37.7%. Thus, on day 1 of the study, all participants may have presence of pulmonary edema. The participants’ LIRs over time are presented in
The number of days the patients participated in the self-assessment varied because of technical or health-related reasons. Patient number 2 had 26 days of data, patient number 3 had 19 days of data, and patient number 4 had 23 days of data (
Individual lung impedance ratios (ΔLIRs) during the 30-day postdischarge at-home assessment period. Each color or symbol represents the ΔLIR time series for 1 of the 10 participants. More negative ΔLIRs translate to more pulmonary congestion. Missing data (interrupted time series) resulted from a poor electrode connection, an intervening hospitalization, or a participant temporarily lacking help from their home caregiver to perform measurements. An Edema Guard Monitor (CardioSet Medical) lung impedance device was used to measure lung impedance (see the Methods section for calculation of ΔLIR).
Self-care behavior improved from the time they were discharged to the end of the 30-day assessment period. The total score on the EHFScBS at the end was significantly better (
Comparison of heart failure participants’ self-care behavior at hospital discharge and 30 days later at the outpatient clinic as assessed with the European Heart Failure Self-care Behavior Scale (European Heart Failure Self-care Behavior Scale-9 comprises 9 items scored on a Likert scale of 1-5, with a higher score indicating better adherence to the given behavior; N=10).
Behavior | Discharge, median (IQR) | 30 days, median (IQR) | |
I weigh myself every day | 4.5 (1.8-5) | 5 (4.8-5) | .04 |
If my shortness of breath increases, I contact my doctor/nurse | 2.5 (1-5) | 5 (3-5) | .07 |
If my feet/legs become swollen, I contact my doctor/nurse | 3.5 (1-5) | 5 (3.8-5) | .08 |
If I gain 2 kg in 1 week, I contact my doctor/nurse | 2.5 (1- 4.3) | 4.5 (2.8-5) | .14 |
I limit the amount of fluids I drink (<1.5 to 2 L per day) | 3.5 (2-5) | 4.5 (4-5) | .06 |
If I experience increased fatigue, I contact my doctor/nurse | 2.5 (1.8-3.3) | 5 (1.8-5) | .07 |
I eat a low-salt diet | 3.5 (2-5) | 5 (4-5) | .03 |
I take my medication as prescribed | 5 (4.8-5) | 5 (5-5) | .18 |
I exercise regularly | 2 (1-3) | 3.5 (2-5) | .01 |
European Heart Failure Self-care Behavior Scale, 9 items, total standardized scorea | 56 (22-75) | 81 (72-98) | .007 |
Consulting behavior | 55 (38-79) | 88 (58-100) | .049 |
aStandardized or summed scores on the European Heart Failure Self-care Behavior Scale, 9 items, ranged from 0 to 100, with higher scores indicating better self-care behavior.
Our main finding was that HF patients were able to successfully use a symptom diary and measure aided noninvasive lung impedance at home to self-monitor and report HF symptoms during the 30-day postassessment. This is the first study in which HF patients would use the Edema Guard Monitor to measure their lung impedance on a daily basis for 30 days following hospital discharge to home. Previously, the Edema Guard Monitor had been used by health care professionals once a month at an outpatient clinic with HF patients [
The age range of our participants was 37 to 85 years, and our findings are in line with some reports showing that older patients accept and manage well when using new technology [
Typically, after discharge from hospital, HF patients are referred to their general practitioner in the community health care services for follow-up and medication adjustments. In Norway, follow-up at an HF outpatient clinic requires a referral from the hospital ward or general practitioner, currently occurring only 21% of the time [
Another finding was that participants’ self-reported ratings on the 5 key HF symptoms and on the lung impedance measurements varied greatly. The variability in HF symptoms over the course of the assessment period stresses that constant attention is needed to achieve symptom relief. Some authors also warn that HF patients acclimate to symptoms and adapt their activities and lifestyle to reduce the HF symptoms; thus, they might not recognize these symptoms as warning signs [
HF decompensation is the worsening of HF symptoms and signs and is characterized by a gradual decrease in lung impedance measurements in patients at high risk for volume overload [
We observed that self-care behavior of the study participants significantly improved after using the daily symptom diary and taking daily lung impedance measurements. At discharge, our participants had inadequate self-care. According to the EHFScBS, a score of 70 or higher reflects adequate self-care behavior [
One limitation is that only 10 patients participated in this study. Nonetheless, we were able to obtain a substantial amount of data from these participants, and these data provided us with an in-depth understanding of the trajectory of HF symptoms during the first month at home after hospitalization. The variability of the data for HF symptoms and LIR, in addition to our small sample, made it not advisable to perform an analysis for possible associations among these variables. Another limitation is the use of an unvalidated version of the MSAS-HF for the purpose of daily self-monitoring for 30 days at home. However, the unvalidated version did include 5 HF symptoms of fluid overload that are also recommended in guidelines [
This is the first study showing that discharged HF patients can successfully use a symptom diary combined with measurement of their noninvasive lung impedance at home to self-monitor on a daily basis, with support from informal caregivers. We found a significant improvement in the participants’ self-care behavior in the period between hospital discharge and end of the 30-day home assessment. These self-care tools can be used by nurses in clinical practice to educate HF patients and their informal caregivers before discharge to home, which could also reduce readmissions. For future research, a larger study population is needed to determine whether self-monitoring of particular HF symptoms at home and LIR are predictive of HF deterioration. Early detection of worsening HF at home will aid health care professionals in providing better HF care.
Charlson Comorbidity Index
European Heart Failure Self-care Behavior Scale
heart failure
lung impedance ratio
Memorial Symptom Assessment Scale-Heart Failure
New York Heart Association
This work was supported by the Nordic funding organization, NordForsk. The study was funded under Nordic Programme on Health and Welfare, project number: 76015, “Symptom monitoring after hospitalization in patients with advanced heart failure–a Nordic-Baltic study.” The authors wish to thank all participants, their informal caregivers, and health care professionals who participated in the study. The authors thank the photographer/graphic designer Per Marius Didriksen at Oslo University Hospital for designing and producing the layout of study material and for
None declared.