Thirst symptoms in patients with heart failure: An integrative review

AIM

To identify the risk and protective factors affecting thirst symptoms in patients with heart failure (HF) and intervention strategies to alleviate thirst symptoms.

DESIGN

An integrative review.

METHODS

A total of 61 articles were retrieved. Screening yielded a total of 21 articles which were appraised for quality. The quality of studies was assessed using the Mixed Methods Appraisal Tool.

DATA SOURCES

Ten electronic databases were searched in October 2023, including Embase, Pubmed, CINAHL, Cochrane, Web of Science, Wiley, CNKI, VIP, CBM and WanFang. In addition, we searched grey databases and manually searched reference lists of included and relevant reviews.

RESULTS

In total, 1644 articles were retrieved, of which 21 were included. Eight studies addressed the factors. Six themes emerged as risk factors, including demographics, severity of disease, psycho-environmental, medication, fluid restriction and homeostasis. Conversely, an increase in fluid intake, a high score of sodium restriction diet attitude and using ARB were identified as protective factors. Thirteen studies focus on intervention strategies. Five unique intervention strategies were identified, including Traditional Chinese Medicine, mint-related interventions, sour-flavour interventions, improved water restriction and cluster nursing strategy.

CONCLUSION

This finding identified the factors associated with thirst symptoms in patients with HF, especially concerning the elaboration of risk factors, which suggests that healthcare professionals should focus on the risk factors for thirst in patients with HF and consciously avoid the occurrence of these risk factors. Additionally, there are considerable cultural differences in interventions, therefore, to increase adherence during symptom management, careful selection of appropriate intervention strategies based on the requirements and preferences of patients is required. While there are some therapies, there aren't enough high-quality empirical investigations. Thus, multi-centre, large-sample studies are also required in subsequent research to demonstrate the interventions' effectiveness.

IMPLICATIONS FOR THE PROFESSION

The nurse must notice the symptoms of thirst in HF to slow down the disease's progression and improve the patient's physical and emotional well-being.

REPORTING METHOD

The review complies with the PRISMA guidelines for reporting systematic reviews.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution.

Non-pharmacological interventions to reduce thirst in patients with heart failure or hemodialysis: A systematic review and meta-analysis

BACKGROUND

Thirst is a frequent and burdening symptom in many patients, especially in patients with chronic heart failure (CHF) and/or receiving hemodialysis (HD). As drug therapies are not feasible, non-pharmacological strategies are needed to reduce thirst and thirst-related burden.

OBJECTIVES

To identify non-pharmacological interventions aiming to reduce thirst in patients with CHF and/ or HD, to describe intervention components, and to evaluate the effectiveness of these interventions.

METHODS

In February 2024, we completed a systematic search in MEDLINE via PubMed, Livivo, CINAHL, Cochrane Library and Web of Science. Two reviewers independently screened titles, abstracts, and full texts, performed critical appraisal and data extraction. We checked risk of bias with the checklists of the Joanna Briggs Institute and the Cochrane Risk of Bias tool and calculated meta-analyses for sufficiently homogeneous studies using fixed-effects models.

RESULTS

We included 15 intervention studies applying non-pharmacological interventions including chewing gum (n = 8), low-sodium diet (n = 2), acupressure (n = 1), frozen strawberries (n = 1), fluid timetables (n = 1), ice cubes and mouthwash (n = 1), and a psychological intervention (n = 1). Sample sizes varied between 11 and 88 participants. Eleven intervention studies showed a reduction of thirst as intervention effect. Meta-analyses for chewing gum showed no significant effect on thirst using a visual analogue scale (IV: -2,32 [-10.37,5.73]; p = 0.57) or the dialysis thirst inventory (IV: -0.26 [- 1.83, 1.30]; p = 0.74). Quality of studies was moderate to low.

CONCLUSION

Results indicate that various non-pharmacological interventions could be helpful to reduce thirst in patients with CHF or HD, but important uncertainty remains.

[Consensus recommendations on the diagnosis and treatment of hyponatremia from the Austrian Society for Nephrology 2024]

Hyponatremia is a disorder of water homeostasis. Water balance is maintained by the collaboration of renal function and cerebral structures, which regulate thirst mechanisms and secretion of the antidiuretic hormone. Measurement of serum-osmolality, urine osmolality and urine-sodium concentration help to diagnose the different reasons for hyponatremia. Hyponatremia induces cerebral edema and might lead to severe neurological symptoms, which need acute therapy. Also, mild forms of hyponatremia should be treated causally, or at least symptomatically. An inadequate fast increase of the serum sodium level should be avoided, because it raises the risk of cerebral osmotic demyelination. Basic pathophysiological knowledge is necessary to identify the different reasons for hyponatremia which need different therapeutic procedures.

Origins of thirstiness sensation and current food solutions

The sensation of thirstiness is the desire to drink water. In certain situations, the ingestion of liquid water can be restricted. As a result, thirstiness is not relieved, resulting in an uncomfortable and distressing situation. The present review describes thirstiness and hydration, the food products and beverages that cause thirstiness, and the beverages and food products currently available to quench thirstiness in individuals with restricted access to liquid ingestion. It also discusses how to measure the effectiveness of calming thirstiness. To diminish thirstiness distress, different alternatives to liquids are proposed. Individuals with swallowing disorders are given thickened water, individuals with restricted water ingestion are given ice cubes or ice popsicles of different flavors, and sportspeople are given energy gels. However, current beverage solutions seem not to relieve thirst fully, although some stimuli like iced water, flavors (especially lemon and mint), or acids seem to work better than plain stimuli and could be added to existing products. Therefore, there is still a need to incorporate these strategies into beverage and food formulations and to test their effectiveness.

Hyponatraemia and changes in natraemia during hospitalization for acute heart failure and associations with in-hospital and long-term outcomes - from the ESC-HFA EORP Heart Failure Long-Term Registry

AIMS

To comprehensively assess hyponatraemia in acute heart failure (AHF) regarding prevalence, associations, hospital course, and post-discharge outcomes.

METHODS AND RESULTS

Of 8298 patients in the European Society of Cardiology Heart Failure Long-Term Registry hospitalized for AHF with any ejection fraction, 20% presented with hyponatraemia (serum sodium <135 mmol/L). Independent predictors included lower systolic blood pressure, estimated glomerular filtration rate (eGFR) and haemoglobin, along with diabetes, hepatic disease, use of thiazide diuretics, mineralocorticoid receptor antagonists, digoxin, higher doses of loop diuretics, and non-use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and beta-blockers. In-hospital death occurred in 3.3%. The prevalence of hyponatraemia and in-hospital mortality with different combinations were: 9% hyponatraemia both at admission and discharge (hyponatraemia Yes/Yes, in-hospital mortality 6.9%), 11% Yes/No (in-hospital mortality 4.9%), 8% No/Yes (in-hospital mortality 4.7%), and 72% No/No (in-hospital mortality 2.4%). Correction of hyponatraemia was associated with improvement in eGFR. In-hospital development of hyponatraemia was associated with greater diuretic use and worsening eGFR but also more effective decongestion. Among hospital survivors, 12-month mortality was 19% and adjusted hazard ratios (95% confidence intervals) were for hyponatraemia Yes/Yes 1.60 (1.35-1.89), Yes/No 1.35 (1.14-1.59), and No/Yes 1.18 (0.96-1.45). For death or heart failure hospitalization they were 1.38 (1.21-1.58), 1.17 (1.02-1.33), and 1.09 (0.93-1.27), respectively.

CONCLUSION

Among patients with AHF, 20% had hyponatraemia at admission, which was associated with more advanced heart failure and normalized in half of patients during hospitalization. Admission hyponatraemia (possibly dilutional), especially if it did not resolve, was associated with worse in-hospital and post-discharge outcomes. Hyponatraemia developing during hospitalization (possibly depletional) was associated with lower risk.

Thirst in heart failure: A scoping review

AIM

The aim of this study was to summarise the overall picture of thirst-related research in patients with heart failure.

DESIGN

We conducted a scoping review following the Arskey and O'Malley methodological framework along with the PAGER framework.

METHODS

PubMed, CINAHL, Web of Science, Embase, The Cochrane Library, Jonna Briggs Institute, ProQuest Database, Google Scholar, PsycINFO, PQDT, CNKI, Wan Fang, VIP and CBM. Additionally, grey literature including grey databases (Opengrey, OpenDoar, Openaire and BASEL Bielefeld Academic Search Engine), conferences or articles (Scopus and Microsoft Academic), graduate theses databases (eTHOS, DART Europe, Worldcat and EBSCO Open Dissertations) and government information media (UK guidance and regulations, USA government websites, EU Bookshop and UN official publications) were searched. The databases were searched from inception to 18 August 2022 for Articles written in English and Chinese. Two researchers independently screened articles based on inclusion and exclusion criteria, and a third researcher adjudicated disagreements.

RESULTS

We retrieved 825 articles, of which 26 were included. Three themes were summarised from these articles: (a) the incidence of thirst in patients with heart failure; (b) the thirst-related factors in patients with heart failure; and (c) the intervention measures of thirst in patients with heart failure.

Association Between Self-care and Resilience: A Cross-sectional Study in Heart Failure Patients

BACKGROUND

Self-care (SC) is a cornerstone in heart failure management and is related to patient outcomes. The continuous and complex demands of SC can be experienced as stressful and may require patients to apply resilient behaviors as they manage their conditions. Resilience may be a helpful factor in performing SC.

OBJECTIVE

The aim of this study was to determine the association between resilience and SC in patients with heart failure.

METHODS

A cross-sectional study was performed between January 2020 and January 2021. Participants were asked to complete a questionnaire addressing baseline characteristics, the 2-item Patient Health Questionnaire, the Resilience Evaluation Scale, and the Self-Care of Chronic Illness Inventory, which measures 3 concepts of SC: SC maintenance, SC monitoring, and SC management. Multiple regression analysis was performed to determine whether resilience was associated with SC.

RESULTS

Eighty-six patients were included, and 74 patients completed the questionnaire. In the univariate analysis, an association was found between resilience and SC maintenance, resulting in an increase in SC for patients with higher resilience (β = 0.24; 95% confidence interval, 0.03-0.96). In the multivariate analysis adjusted and corrected for confounders, no significant associations between resilience and all SC scales were found.

CONCLUSION

This study could not demonstrate significant associations between resilience and all SC scales. This study contributes to the body of knowledge on factors that can mediate or moderate SC. Further longitudinal research should be performed to study cause-effect relationships.

Translation and Psychometric Evaluation of the German Version of the Thirst Distress Scale for Patients With Heart Failure

BACKGROUND

In patients with chronic heart failure, thirst can be perceived as an intensive and burdensome symptom, which may have a negative impact on patients' quality of life. To initiate thirst-relieving interventions, assessment of thirst and its related distress is essential. At the time of this study, no instrument was available to evaluate thirst distress in patients with heart failure in Germany.

OBJECTIVE

The aims of this study were to translate the "Thirst Distress Scale for patients with Heart Failure" (TDS-HF) from English into German and to test validity and reliability of the scale.

METHODS

The English version of the TDS-HF was translated into German. A linguistically and culturally sensitive forward-and-backward translation was performed. Psychometric evaluation included confirmatory factor analysis, reliability in terms of internal consistency, and concurrent validity.

RESULTS

Eighty-four hospitalized patients (mean age, 72 ± 10 years; 29% female; mean left ventricular ejection fraction, 36% ± 12%; 62% New York Heart Association functional classes III-IV, 45% on fluid restriction) from an acute care hospital were involved in the study. The item-total correlation ranged from 0.58 to 0.78. Interitem correlations varied between 0.37 and 0.79. Internal consistency was high, with a Cronbach α of 0.89. There was a high correlation between the total score of the TDS-HF and the visual analog scale to assess thirst intensity ( r = 0.72, P ≤ .001), and a low correlation with fluid restriction ( r = 0.35, P = .002).

CONCLUSIONS

The evaluation of the German TDS-HF showed satisfactory psychometric properties in this sample. The instrument is usable for further research and additional psychometric testing.

Fluid REStriction in Heart failure versus liberal fluid UPtake: Rationale and design of the randomised FRESH-UP study

AIMS

It is common practice for clinicians to advise fluid restriction to heart failure (HF) patients, but data from clinical trials are lacking. Moreover, fluid restriction is associated with thirst distress and may adversely impact quality of life (QoL). To address this gap in evidence, the Fluid REStriction in Heart failure versus liberal fluid UPtake (FRESH-UP) study was initiated.

METHODS

The FRESH-UP study is a randomised, controlled, open-label, multicentre trial to investigate the effect of a 3-month period of liberal fluid intake versus fluid restriction (1500ml/day) on QoL in outpatient chronic HF patients (NYHA II-III). The primary aim is to assess the effect on QoL after 3 months using the Overall Summary Score of the Kansas City Cardiomyopathy Questionnaire (KCCQ). Thirst distress as assessed by the Thirst Distress Scale for patients with HF, KCCQ Clinical Summary Score, each of the KCCQ domains and clinically meaningful changes in these scores, the EQ-5D-5L, patient reported fluid intake and safety (i.e. death, HF hospitalisations) are secondary outcomes. The FRESH-UP study is registered at ClinicalTrials.gov (NCT04551729).

CONCLUSION

The results of the FRESH-UP study will substantially add to the level of evidence concerning fluid management in chronic HF and may impact QoL of these patients.

Clinical predictors of hyponatremia in patients with heart failure according to severity of chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) has been associated with adverse clinical outcomes. Hyponatremia, a marker of illness severity and poor prognosis, is commonly exhibited in patients with CKD.

METHODS

This cross-sectional study included patients hospitalized due to heart failure (HF). We used stepwise logistic regression to investigate the independent association of cardiovascular drugs, markers of HF severity, and baseline clinical characteristics with hyponatremia in three subgroups; normal renal function, mild-to-moderate CKD, and severe CKD.

RESULTS

Of the 1232 patients, 38.6% were hyponatremic. Patients with severe CKD, compared to those with normal renal function and mild-to-moderate CKD, were more likely to be hyponatremic (47.1%, 34.4% and 36.6%, respectively; p ≤ 0.0001). Alcohol consumption, female sex, n-terminal pro-brain natriuretic peptide (NT-proBNP), hydrochlorothiazide (HCT), and mineralocorticoid receptor antagonist (MRA) use, or angiotensin II receptor I blocker (ARB) non-use were associated with hyponatremia in patients with normal renal function (p ≤ 0.03 in all cases). Current smoking, diabetes mellitus, NT-proBNP, loop diuretic dose, and MRA use were predictors in mild-to-moderate CKD (p ≤ 0.04 in all cases). ARB use, loop diuretic dose, and HCT use were predictors in severe CKD (p ≤ 0.03 in all cases). Non-use of dihydropyridine calcium channel blocker (CCB) was an independent predictor of hyponatremia in all CKD stages (p ≤ 0.04 in all cases).

CONCLUSION

Apart from a firm favorable effect of CCBs, cardiovascular therapy should be carefully tailored to avoid hyponatremia in patients with cardiorenal syndrome.

Sodium and/or fluid restriction and nutritional parameters of adult patients with heart failure: A systematic review and meta-analysis of randomized controlled trial

INTRODUCTION

Heart failure (HF) is a clinical syndrome resulting from the structural and/or functional impairment of blood supply to tissues. Congestion and edema associated with water retention are the main symptoms presented by patients. Fluid (FR) and sodium restriction are non-pharmacological measures indicated in clinical practice to mitigate this symptom, despite their low evidence level.

AIM

Assessing the impact of sodium and/or fluid restriction on nutritional parameters of adult patients with HF, based on systematic review with meta-analysis.

METHODS

The study was conducted in June 2020, on the following databases: EMBASE, PubMed/MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science. Citations were also collected in the gray literature such as thesis banks and preprints. Randomized clinical trials conducted with patients in the age group 18 years, or older, who were hospitalized or under outpatient/clinical follow-up, and who were subjected to intervention based on fluid and/or sodium restriction in comparison to the control, were herein selected.

RESULTS

Although FR-based diets are effective in reducing liquid intake, they increase individuals' thirst sensation and body weight in comparison to non-FR diets. The association between this intervention and sodium restriction is also effective in reducing liquid intake as sodium intake decreases. However, the association of the most severe (<2000 mg/day) and moderate (2000-2400 mg/day) sodium restrictions with FR has reduced energy intake, although without evidence of weight change - only the most severe sodium restriction was capable of keeping individuals' thirst sensation. In addition, moderate sodium restrictions (2300 to 3000 mg/day) in association with FR were capable of decreasing urinary sodium excretion. On the other hand, prescriptions of severe or moderate sodium restriction (<2,400 mg/d) alone have reduced individuals' body weight and BMI, although they did not change their caloric intake. However, severe sodium restriction (<2,000 mg) has led to higher body weight than the low-sodium diet (2000 to 2,4000 mg/day).

CONCLUSION

Sodium restriction may not be an effective strategy because it adversely affects individuals' weight, a fact that suggests increased congestion. Weight-based FR is supported to bethe best way to individualize this non-pharmacological treatment and it does not appear to affect nutritional parameters capable of putting patients with HF at higher malnutrition risk.

Thirst distress in outpatients with heart failure in a Mediterranean zone of Spain

Aims

This study aimed to evaluate psychometric properties of the Spanish version of the Thirst Distress Scale for patients with Heart Failure (TDS‐HF) and to describe thirst distress‐associated factors in outpatients at a heart failure (HF) clinic in Spain. Thirst is common in patients with HF, but thirst distress has rarely been addressed and may significantly decrease quality of life.

Methods and results

A cross‐sectional study was performed assessing perceived thirst distress by patients with HF during the preceding 3 days, with the TDS‐HF (scores 8 to 40). Univariable and multivariable linear regression analyses were performed to identify variables independently associated with thirst distress. Three‐hundred two HF outpatients were included (age 67 ± 12 years, 74% male, HF duration 82 ± 75 months, left ventricular ejection fraction 42 ± 14%). Most patients were on treatment with fluid restriction (99%), sodium restriction (99%), and diuretics (70%). The psychometric evaluation of the Spanish version of the TDS‐HF showed satisfactory item‐total and inter‐item correlations (range from 0.77 to 0.85 and 0.60 to 0.84, respectively), and internal consistency was 0.95 (Cronbach's alpha). The majority perceived mild to moderate thirst distress, and 18% perceived it as high or severe. The mean score obtained was 16.2 ± 9.3 (median 13, Q1–Q3 8–20). Higher serum urea {beta coefficient 1.6 [95% confidence interval (CI) 0.267 to 2.92], P = 0.019} and lower potassium [beta coefficient −3.63 (85% CI −6.32 to −0.93), P = 0.009] remained significantly associated with thirst distress in the multivariable analysis, together with the dose of diuretics [beta coefficient 2.98 (95% CI 1.37 to 4.59), P < 0.001]. Treatment with angiotensin receptor blocker showed an independent protective effect [beta coefficient −3.62 (95% CI −6.89 to −0.345), P = 0.03].

Conclusions

The psychometric evaluation of the Spanish version of the TDS‐HF showed good psychometric properties. One in five patients experienced severe distress by thirst, but the majority had mild to moderate thirst distress. The dose of diuretics and angiotensin receptor blocker treatment influence thirst distress and could be clinically important targets to relieve thirst distress in patients with HF.

A RandomisEd ControLled TrIal of ChEwing Gum to RelieVE Thirst in Chronic Heart Failure (RELIEVE-CHF)

BACKGROUND

Thirst is a common and troublesome symptom of patients with chronic heart failure (CHF). To date, there are no interventions to help alleviate thirst in this cohort. Chewing gum is a novel intervention, which has been tested in people undergoing haemodialysis, also prescribed with a fluid restricted therapy. The aim of this study was to determine the effect of chewing gum on the level of thirst in the short-term (average of 24 hours each day for 4 days) and in the longer-term (Days 7, 14 and 28) individuals with CHF.

METHODS

Seventy-one (71) individuals with CHF on oral loop diuretics were randomised to chewing gum (n=36) or control (n=35) for 2 weeks. Both groups were assessed for their level of thirst at Days 1-4, 7, 14 and 28.

RESULTS

Significant improvements in the level of thirst of those who received chewing gum compared to the control group at Day 4 (p=0.04) and Day 14 (p=0.02) were observed.

CONCLUSION

Chewing gum provided relief from thirst in the short-term and in the longer term. This trial provides important information to inform future clinical trials on ways to relieve thirst.

Thirst and factors associated with frequent thirst in patients with heart failure in Spain

BACKGROUND

Thirst is a troublesome symptom in patients with Heart Failure (HF) and one that might be perceived differently in different countries depending on climate, food and cultural habits. The aims of the study were to describe thirst frequency, duration and intensity and to identify factors associated with frequent thirst in outpatients with HF in a Mediterranean country.

METHODS

Data was collected in a cross-sectional study involving 302 patients diagnosed with HF (age 67±12 years, 74% male, LVEF 43%±14) in Spain on thirst frequency and duration, and thirst intensity by patient self-report (VAS, 0-100 mm). Clinical variables were collected from the medical files. Regression analysis was used to identify factors independently associated with frequent thirst.

RESULTS

Of all the patients, 143 (47%) were frequently thirsty, and their median (25^th and 75^th percentiles) thirst intensity was higher (VAS 50 mm [20-67] vs 7 [0-20], p<.001). Their thirst lasted longer compared to those who never/sometimes were thirsty (p<.001). Less treatment with angiotensin receptor blockers (Odds Ratio [OR] 2.72; 95% Confidence Interval [CI] 1.33-5.58), diuretics >40 mg/day (OR 1.92; 95% CI 1.02-3.64), depression (OR 2.99; CI 1.17-7.62), male gender (OR 1.98; CI 1.08-3.64) and worse New York Heart Association functional class (OR 1.92; 95% CI 1.05-3.52) were independently associated with frequent thirst.

CONCLUSIONS

About half of patients with HF and fluid restriction experienced frequent thirst in a Mediterranean area of Spain, and their thirst duration and intensity were significantly increased. Frequent thirst was associated with demographic, clinical and therapeutic variables. The results may help to identify patients with a higher risk of frequent thirst and might suggest therapeutic changes in order to diminish this troublesome symptom.

Racial Differences in Diuretic Efficiency, Plasma Renin, and Rehospitalization in Subjects With Acute Heart Failure

BACKGROUND

Black patients have higher rates of hospitalization for acute heart failure than other race/ethnic groups. We sought to determine whether diuretic efficiency is associated with racial differences in risk for rehospitalization after acute heart failure.

METHODS

A post hoc analysis was performed on 721 subjects (age, 68±13 years; 22% black) enrolled in 3 acute heart failure clinical trials: ROSE-AHF (Renal Optimization Strategies Evaluation in Acute Heart Failure), DOSE-AHF (Diuretic Optimization Strategy Evaluation in Acute Decompensated Heart Failure), and CARRESS-HF (Cardiorenal Rescue Study in Acute Decompensated Heart Failure). Repeated-measures ANOVA was used to test for a race×time effect on measures of decongestion. Diuretic efficiency was calculated as net fluid balance per total furosemide equivalents. In a subset of subjects, Cox regression was used to examine the association between race and rehospitalization according to plasma renin activity (PRA).

RESULTS

Compared with nonblack patients, black patients were younger and more likely to have nonischemic heart failure. During the first 72 to 96 hours, there was greater fluid loss (P=0.001), decrease in NT-proBNP (N-terminal pro-B-type natriuretic peptide; P=0.002), and lower levels of PRA (P<0.0001) in black patients. Diuretic efficiency was higher in black than in nonblack patients (403 [interquartile range, 221-795] versus 325 [interquartile range, 154-698]; P=0.014). However, adjustment for baseline PRA attenuated the association between black race and diuretic efficiency. Over a median follow-up of 68 (interquartile range, 56-177) days, there was an increased risk of all-cause and heart failure-specific rehospitalization in nonblack patients with increasing levels of PRA, while the risk of rehospitalization was relatively constant across levels of PRA in black patients.

CONCLUSIONS

Higher diuretic efficiency in black patients with acute heart failure may be related to racial differences in activity of the renin-angiotensin-aldosterone system.

Knowledge, Adherence to Lifestyle Recommendations, and Quality of Life Among Koreans With Heart Failure

OBJECTIVE

To assess heart failure (HF) knowledge, adherence to lifestyle recommendations, and quality of life (QOL) among Koreans with HF and identify factors influencing QOL.

METHODS

A cross-sectional and correlational design was used and a total of 142 Koreans with HF were recruited between April 2012 and September 2013. Data were analyzed using multiple logistic regression with SPSS version 21.0.

RESULTS

The mean age of participants was 64.1 ± 7.4 years. A higher proportion of participants were male, married, unemployed, had a high education level, and class I New York Heart Association (NYHA) functional status. A higher proportion of participants had ≥2 comorbidities and the most prevalent comorbidity was diabetes. The mean score of HF knowledge was 6.9 (possible range 0-15) and the most frequent incorrect items were "proper actions to reduce thirst" and "causes of leg swelling" in both better and worse QOL groups. Among the recommended lifestyle, pneumococcal vaccination had the least adherence in both groups. Multiple logistic regression showed that patients in NYHA class I, with a higher left ventricular ejection fraction, who had knowledge of "amount of fluid intake a day" and consumed more than moderate alcohol tended to have better QOL. Conclusion: More active interventions targeting HF knowledge in proper actions to reduce thirst, causes of leg swelling, and the amount of fluid intake per day are required. Patients with HF in more serious condition need special attention regarding the risk of worse QOL. The role of alcohol consumption in QOL among HF patients in Korea needs further exploration.

Thirst in heart failure: what do we know so far?

PURPOSE OF REVIEW

Thirst is a common and burdensome symptom of heart failure, which impacts adversely on quality of life. To date, there is limited research on the prevalence of thirst, the factors associated with thirst and interventions to help manage thirst in heart failure. This review summarizes key empirical research developments of thirst.

RECENT FINDINGS

Recent research shows that the heart failure syndrome, medications, self-care practice such as fluid restriction and anxiety contributes greatly to increased thirst in patients with heart failure. In addition, predictors such as being younger, male patient, with high symptom burden and serum urea is also associated with thirst. There are no intervention studies to manage thirst, only reports of various strategies recommended to heart failure patients in clinical practice.

SUMMARY

Despite the burden of thirst in heart failure patients, strategies to relieve thirst remains insufficiently addressed in literature. Further research to improve the understanding of the severity of thirst and its relationship to possible factors associated with thirst is required in order to develop future interventions to either prevent or alleviate troublesome thirst in patients with heart failure.

Higher Diuretic Requirements in Acute Heart Failure With Admission Hyponatraemia Versus Normonatraemia

BACKGROUND

Diuretic requirements in patients with acute decompensated heart failure (ADHF) and hyponatraemia versus normonatraemia on admission has not been previously explored.

METHODS

The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial dataset was utilised to examine the characteristics and diuretic requirements of patients with ADHF with hyponatraemia or normonatraemia on admission.

RESULTS

Patients with ADHF and admission hyponatraemia (n = 103, average Na 130.2 meq/L) had a higher degree of congestion evident in higher frequency of jugular venous distension (JVD) >12 cmH₂O (p = 0.007), 2+ lower extremity oedema (p = 0.001), and higher right atrial pressure (p = 0.007), compared with normonatraemic patients (n = 327, average Na 138.6 meq/L). Despite a similar baseline furosemide dose in both groups (median 200 mg), the hyponatraemia group received higher in-hospital furosemide (280 vs. 200 mg, in both groups, respectively, p < 0.001) which represented a higher percentage of furosemide utilisation relative to baseline, compared with the normonatraemia group (33% vs 0%, in both groups respectively, p = 0.007). With in-hospital diuresis, the Na level of hyponatraemic subjects started significantly increasing at discharge and up to 6 months after randomisation-all relative to baseline. Hyponatraemic patients had significantly lower systolic blood pressure (SBP) longitudinally at multiple time points compared with normonataremic patients, but it did not further decrease despite the higher furosemide dose in the former group.

CONCLUSION

Patients with ADHF and hyponatraemia on admission had a higher degree of congestion and required higher doses of furosemide, compared with normonatraemic subjects. The lower Na and SBP in this instance should not lead to withholding or minimising diuretic dosage which should rather be dictated by volume status.

Changes in Thirst Intensity During Optimization of Heart Failure Medical Therapy by Nurses at the Outpatient Clinic

BACKGROUND

Thirst can be aggravated in patients with heart failure (HF), and optimization of HF medication can have positive impact on thirst.

OBJECTIVES

The aims of this study were to describe changes in thirst intensity and to determine factors associated with high thirst intensity during optimization of HF medication.

METHODS AND RESULTS

Patients with HF (N = 66) who were referred to an HF clinic for up-titration of HF medication were included. Data were collected during the first visit to the clinic and at the end of the treatment program. Data were dichotomized by the median visual analog scale score for thirst, dividing patients into 2 groups: low thirst intensity (0-20 mm) and high thirst intensity (>20 mm on a visual analog scale of 0-100 mm). In total, 67% of the patients reported a higher thirst intensity after the HF up-titration program. There was no difference in thirst intensity between the patients who reached target doses and those who did not. Plasma urea level (odds ratio, 1.33; 95% confidence interval, 1.07-1.65) and fluid restriction (odds ratio, 6.25; 95% confidence interval, 1.90-20.5) were independently associated with high thirst intensity in patients with HF.

CONCLUSIONS

Thirst intensity increased in two-thirds of the patients during a time period of optimization of HF medication. Fluid restriction and plasma urea levels were associated with high thirst intensity.

Trajectory of thirst intensity and distress from admission to 4-weeks follow up at home in patients with heart failure

BACKGROUND

Patients with heart failure (HF) can suffer from increased thirst intensity and distress. Trajectories of thirst intensity and distress from hospital to home are unclear. The aim of this study was to describe thirst intensity and distress trajectories in patients from the time of hospital admission to 4 weeks after discharge, and describe trajectories of thirst intensity and distress by patients' characteristics (gender, age, body mass index [BMI], plasma urea, anxiety, and depression).

PATIENTS AND METHODS

In this observational study, data were collected from patients with HF (n=30) at hospital admission, discharge, and at 2 and 4 weeks after discharge. Thirst intensity (visual analog scale, 100 mm) and distress (Thirst Distress Scale-HF, score 9-45) were used. Trajectories were examined using growth modeling.

RESULTS

Trajectory of the thirst intensity was significantly different, for patients with low and high thirst intensity levels (median cut-off 39 mm), from admission to 4 weeks follow up (thirst increased and decreased, respectively). Patients with high level of thirst distress (median score >22) at admission, having fluid restriction and women continued to have higher thirst distress over time. Patients feeling depressed had higher thirst intensity over time. There were no differences in the trajectories of thirst intensity and distress by age, BMI, plasma urea, and anxiety.

CONCLUSION

Intensity and distress of thirst, having fluid restriction, and feeling depressed at the admission were critical in predicting the trajectory of thirst intensity and distress after discharge to home in patients with HF. Effective intervention relieving thirst should be provided before their discharge to home.

Frequent drinking of small volumes improves cardiac function and survival in rats with chronic heart failure

Fluid retention is the main reason for the high hospitalization rate among patients with chronic heart failure (CHF). Given the lack of knowledge about fluid intake regulation and its consequences in patients with CHF, current guidelines do not provide clear direction for fluid management. Using a rat model of CHF, we investigated altering drinking behaviors and explored fluid management strategies. CHF was induced by ligating the left anterior descending coronary arteries in 8‐week‐old, male, Sprague‐Dawley rats. A custom‐designed drop counting and feedback control system was used to record and modulate drinking behaviors. During the first month after an induced myocardial infarction (MI), we observed that the spontaneous per drinking volume (PDV) was significantly increased in animals with prolonged intervals between drinking episodes. In addition, there was a significant inverse correlation between the early PDV and the post‐MI lifespan (r = −0.907; P < 0.001). Moreover, modulating the drinking behavior of rats with CHF to involve frequent drinking of small PDVs significantly enhanced hemodynamics and prevented cardiac remodeling, with a significant improvement in the 180‐day survival rate, compared with animals allowed to drink freely (50% vs. 36%; P < 0.01). The results of dynamic PDV changes, after MI, suggest that an impaired thirst mechanism is associated with the sensing and regulating of fluid balance in rats with CHF. These results suggest that increasing the drinking frequency, with small PDVs, may be beneficial to preventing progression of cardiac dysfunction in CHF.

Development and psychometric evaluation of the Thirst Distress Scale for patients with heart failure

BACKGROUND

Patients with heart failure can experience thirst distress. However, there is no instrument to measure this in patients with heart failure. The aim of the present study was to develop the Thirst Distress Scale for patients with Heart Failure (TDS-HF) and to evaluate psychometric properties of the scale.

METHODS AND RESULTS

The TDS-HF was developed to measure thirst distress in patients with heart failure. Face and content validity was confirmed using expert panels including patients and healthcare professionals. Data on the TDS-HF was collected from patients with heart failure at outpatient heart failure clinics and hospitals in Sweden, the Netherlands and Japan. Psychometric properties were evaluated using data from 256 heart failure patients (age 72±11 years). Concurrent validity of the scale was assessed using a thirst intensity visual analogue scale. Patients did not have any difficulties answering the questions, and time taken to answer the questions was about five minutes. Factor analysis of the scale showed one factor. After psychometric testing, one item was deleted. For the eight item TDS-HF, a single factor explained 61% of the variance and Cronbach's alpha was 0.90. The eight item TDS-HF was significantly associated with the thirst intensity score ( r=0.55, p<0.001). Regarding test-retest reliability, the intraclass correlation coefficient was 0.88, and the weighted kappa values ranged from 0.29-0.60.

CONCLUSION

The eight-item TDS-HF is valid and reliable for measuring thirst distress in patients with heart failure.

Clinical aspects of changes in water and sodium homeostasis in the elderly

The population of elderly individuals is increasing worldwide. With aging, various hormonal and kidney changes occur, both affecting water homeostasis. Aging is a risk factor for chronic kidney disease (CKD) and many features of CKD are reproduced in the aging kidney. Dehydration and hyperosmolarity can be triggered by diminished thirst perception in this population. Elderly with dementia are especially susceptible to abnormalities of their electrolyte and body water homeostasis and should be (re-)assessed for polypharmacy. Hypo- and hypernatremia can be life threatening and should be diagnosed and treated promptly, following current practice guidelines. In severe cases of acute symptomatic hyponatremia, a rapid bolus of 100 to 150 ml of intravenous 3% hypertonic saline is appropriate to avert catastrophic outcomes; for asymptomatic hyponatremia, a very gradual correction is preferred. In summary, the body sodium (Na+) balance is regulated by a complex interplay of environmental and individual factors. In this review, we attempt to provide an overview on this topic, including dehydration, hyponatremia, hypernatremia, age-related kidney changes, water and sodium balance, and age-related changes in the vasopressin and renin-angiotensin-aldosterone system.

The effectiveness of individual rehabilitation on health status in patients with heart failure: A quasi-experimental study

Patients with heart failure (HF) live with a serious disease, and need long-term rehabilitation care. Elements in rehabilitation for patients with HF are based on the recommendations from the European Society of Cardiology and focuses on self-care and adherence in general. The aim of this study is to test the effect of individually prepared rehabilitation plans measured on health status (HS). The study design is quasi-experimental. Patients in the control group follow the conventional rehabilitation. For the patients in the intervention group. an individual rehabilitation plan was prepared and followed up by telephone after 4 and 12 weeks. For all patients, HS was measured with Short Form-36. One hundred sixty-two patients are included in the study, of which 137 (84.6%) consented. There were no differences in HS before and after the intervention. There are no significant differences by use of a systematically prepared intervention compared with usual care for patients with HF measured on HS 3 months after discharge from the outpatient clinic.

A survey of views and opinions of health professionals managing thirst in chronic heart failure

BACKGROUND

Thirst is a common and burdensome symptom of chronic heart failure (CHF) which affects adherence to self-care practices specifically fluid restriction. Despite this, there is no standard clinical practice for managing the symptom of thirst.

AIMS AND OBJECTIVES

The aim is to identify the current strategies recommended by health professionals to help relieve thirst in CHF patients and their perceived usefulness of these strategies.

METHODS

A survey was distributed to attendees of the 8th Annual Scientific Meeting of Australasian Cardiovascular Nursing College.

RESULTS

There were 42 of 70 respondents to the survey. The majority (33 of 40; 82.5%) had recommended various strategies to alleviate thirst. The most recommended strategy was ice chips (36 of 38; 94.7%). Overall, the respondents reported 'some use' in all of the strategies.

CONCLUSION

Information from this survey may help in the incorporation of thirst-relieving strategies into evidence-based guidelines; further improving the quality of care of patients.

Fluid restriction in patients with heart failure: how should we think?

BACKGROUND/AIM

Fluid restriction has long been considered one of the cornerstones in self-care management of patients with heart failure. The aim of this discussion paper is to discuss fluid restriction in heart failure and propose advice about fluid intake in heart failure patients.

RESULTS

Although there have been seven randomised studies on fluid restriction in heart failure patients, the effect of fluid restriction on its own were only evaluated in two studies. In both studies, a stringent fluid restriction compared to a liberal fluid intake was not more beneficial with regard to clinical stability or body weight. In the other studies fluid restriction was part of a larger study intervention including, for example, individualised dietary recommendations and follow-up by telephone. Thus, the effect of fluid restriction on its own has been poorly evaluated.

CONCLUSION

Fluid restriction should not be recommended to all heart failure patients. However, temporary fluid restriction can be considered in decompensated heart failure and/or patients with hyponatremia. Tailored fluid restriction based on body weight (30 ml/kg per day) seems to be most reasonable. To increase adherence to temporary fluid restriction, education, support and planned evaluations can be recommended.

Rapid and Highly Accurate Prediction of Poor Loop Diuretic Natriuretic Response in Patients With Heart Failure

BACKGROUND

Removal of excess sodium and fluid is a primary therapeutic objective in acute decompensated heart failure and commonly monitored with fluid balance and weight loss. However, these parameters are frequently inaccurate or not collected and require a delay of several hours after diuretic administration before they are available. Accessible tools for rapid and accurate prediction of diuretic response are needed.

METHODS AND RESULTS

Based on well-established renal physiological principles, an equation was derived to predict net sodium output using a spot urine sample obtained 1 or 2 hours after loop diuretic administration. This equation was then prospectively validated in 50 acute decompensated heart failure patients using meticulously obtained timed 6-hour urine collections to quantify loop diuretic-induced cumulative sodium output. Poor natriuretic response was defined as a cumulative sodium output of <50 mmol, a threshold that would result in a positive sodium balance with twice-daily diuretic dosing. Following a median dose of 3 mg (2-4 mg) of intravenous bumetanide, 40% of the population had a poor natriuretic response. The correlation between measured and predicted sodium output was excellent (r=0.91; P<0.0001). Poor natriuretic response could be accurately predicted with the sodium prediction equation (area under the curve =0.95, 95% confidence interval 0.89-1.0; P<0.0001). Clinically recorded net fluid output had a weaker correlation (r=0.66; P<0.001) and lesser ability to predict poor natriuretic response (area under the curve =0.76, 95% confidence interval 0.63-0.89; P=0.002).

CONCLUSIONS

In patients being treated for acute decompensated heart failure, poor natriuretic response can be predicted soon after diuretic administration with excellent accuracy using a spot urine sample.

Camera on Vessel: A Camera-Based System to Measure Change in Water Volume in a Drinking Glass

A major problem related to chronic health is patients’ “compliance” with new lifestyle changes, medical prescriptions, recommendations, or restrictions. Heart-failure and hemodialysis patients are usually placed on fluid restrictions due to their hemodynamic status. A holistic approach to managing fluid imbalance will incorporate the monitoring of salt-water intake, body-fluid retention, and fluid excretion in order to provide effective intervention at an early stage. Such an approach creates a need to develop a smart device that can monitor the drinking activities of the patient. This paper employs an empirical approach to infer the real water level in a conically shapped glass and the volume difference due to changes in water level. The method uses a low-resolution miniaturized camera to obtain images using an Arduino microcontroller. The images are processed in MATLAB. Conventional segmentation techniques (such as a Sobel filter to obtain a binary image) are applied to extract the level gradient, and an ellipsoidal fitting helps to estimate the size of the cup. The fitting (using least-squares criterion) between derived measurements in pixel and the real measurements shows a low covariance between the estimated measurement and the mean. The correlation between the estimated results to ground truth produced a variation of 3% from the mean.

Effects of limiting fluid intake on clinical and laboratory outcomes in patients with heart failure. Results of a meta-analysis of randomized controlled trials

BACKGROUND

The guidelines of the Scientific Societies of Cardiology recommend limiting fluid intake as a nonpharmacological measure for the management of chronic heart failure (HF). However, many patients with HF may suffer from severe thirst. A meta-analysis was performed to evaluate the effect of limiting fluid consumption based on various clinical and laboratory outcomes in patients with chronic HF.

METHODS

Only randomized controlled trials comparing liberal and restricted fluid oral intake in patients with HF were included. Primary outcomes were HF hospitalizations and all-cause mortality. Secondary outcomes were the sensation of thirst, the duration of therapy with intravenous diuretics, and the serum levels of creatinine, sodium, and B-type natriuretic peptide (BNP).

RESULTS

Six studies met the inclusion criteria. Significant heterogeneity was detected for the majority of outcomes. In 5 studies, patients with restricted fluid intake compared to patients with free consumption of beverages had similar rehospitalization and mortality rates. There were no differences regarding patients' sense of thirst (4 studies), duration of intravenous diuretic treatment (2 studies), serum creatinine levels (5 studies), and serum sodium levels (5 studies). Serum BNP levels were significantly higher in the group with free fluid intake (4 studies).

CONCLUSION

In patients with HF, liberal fluid consumption does not seem to exert an unfavorable impact on HF rehospitalizations or all-cause mortality. Further randomized controlled trials are warranted to definitively confirm the present findings.

Berberine attenuates adverse left ventricular remodeling and cardiac dysfunction after acute myocardial infarction in rats: role of autophagy

The present study aimed to test the hypothesis that berberine, a plant-derived anti-oxidant, attenuates adverse left ventricular remodelling and improves cardiac function in a rat model of myocardial infarction (MI). Furthermore, the potential mechanisms that mediated the cardioprotective actions of berberine, in particular the effect on autophagy, were also investigated. Acute MI was induced by ligating the left anterior descending coronary artery of Sprague-Dawley rats. Cardiac function was assessed by transthoracic echocardiography. The protein activity/levels of autophagy related to signalling pathways (e.g. LC-3B, Beclin-1) were measured in myocardial tissue by immunohistochemical staining and western blot. Four weeks after MI, berberine significantly prevented cardiac dysfunction and adverse cardiac remodelling. MI rats treated with low dose berberine (10 mg/kg per day) showed higher left ventricular ejection fraction and fractional shortening than those treated with high-dose berberine (50 mg/kg per day). Both doses reduced interstitial fibrosis and post-MI adverse cardiac remodelling. The cardioprotective action of berberine was associated with increased LC-3B II and Beclin-1 expressions. Furthermore, cardioprotection with berberine was potentially related to p38 MAPK inhibition and phospho-Akt activation. The present in vivo study showed that berberine is effective in promoting autophagy, and subsequently attenuating left ventricular remodelling and cardiac dysfunction after MI. The potential underlying mechanism is augmentation of autophagy through inhibition of p38 MAPK and activation of phospho-Akt signalling pathways.

Predictors of thirst in intensive care unit patients

CONTEXT

Thirst is a pervasive, intense, and distressing symptom in intensive care unit (ICU) patients. Although thirst may be avoided and/or treated, scant data are available to help providers identify patients most in need.

OBJECTIVES

This study was designed to identify predictors of the presence, intensity, and distress of thirst in ICU patients.

METHODS

This descriptive cross-sectional study enrolled 353 patients from three ICUs (medical-surgical, cardiac, and neurological). To measure outcomes, patients were asked to report the presence of thirst (yes/no) and, if present, to rate its intensity and distress on zero to 10 numeric rating scales (10=worst). Predictor variables were demographic (e.g., age), treatment-related (e.g., opioids), and biological (e.g., total body water). Data were analyzed with logistic regression and truncated regression with alpha preset at 0.05.

RESULTS

Thirst presence was predicted by high opioid doses (≥ 50 mg), high furosemide doses (>60 mg), selective serotonin reuptake inhibitors, and low ionized calcium. Thirst intensity was predicted by patients not receiving oral fluid and having a gastrointestinal (GI) diagnosis. Thirst distress was predicted by mechanical ventilation, negative fluid balance, antihypertensive medications, and a GI or "other" diagnosis.

CONCLUSION

Thirst presence was predicted by selected medications (e.g., opioids). Thirst intensity and/or thirst distress were predicted by other treatments (e.g., mechanical ventilation) and medical diagnoses (e.g., GI). This is one of the first studies describing predictors of the multidimensional characteristics of thirst. Clinicians can use these data to target ICU patients whose thirst might warrant treatment.

Thirst in chronic heart failure: a review

AIMS AND OBJECTIVES

This review will (1) explore factors related to thirst in chronic heart failure and (2) describe interventions to alleviate thirst in chronic heart failure patients.

BACKGROUND

Thirst is a common and troublesome symptom of chronic heart failure. Despite the burden and prevalence of this symptom, there are limited strategies to assist in its management.

DESIGN

This is a review of literature on the burden of thirst, contributors to thirst and potential management strategies of thirst in patients with chronic heart failure.

METHODS

Medline, Cumulative Index for Nursing and Allied Health, PubMed and Scopus were searched using the key words thirst, chronic heart failure, angiotensin II, fluid restriction and intervention. Of the 165 citations yielded, nine studies (n = 9) were included. The eligibility criteria included participants with confirmed diagnosis of chronic heart failure, randomised controlled studies or any studies with thirst as primary or secondary outcome, in humans and in English. There was no limit to the years searched.

RESULTS

Factors related to thirst in chronic heart failure were condition; prolonged neurohormonal activation, treatment; pharmacological interventions and fluid restriction and emotion. No intervention studies were found in chronic heart failure patients. Interventions such as artificial saliva and chewing gum have been investigated for their effectiveness as a thirst reliever in haemodialysis patients.

CONCLUSION

Thirst is a frequent and troublesome symptom for individuals with chronic heart failure. It is highly likely that this contributes to poor adherence with fluid restrictions. Chewing gum can help alleviate thirst, but investigation in people with heart failure is needed.

RELEVANCE TO CLINICAL PRACTICE

Increasing awareness of thirst and interventions to relieve it in clinical practice is likely to improve the quality of care for people with chronic heart failure.

Osmotic homeostasis

Alterations in water homeostasis can disturb cell size and function. Although most cells can internally regulate cell volume in response to osmolar stress, neurons are particularly at risk given a combination of complex cell function and space restriction within the calvarium. Thus, regulating water balance is fundamental to survival. Through specialized neuronal "osmoreceptors" that sense changes in plasma osmolality, vasopressin release and thirst are titrated in order to achieve water balance. Fine-tuning of water absorption occurs along the collecting duct, and depends on unique structural modifications of renal tubular epithelium that confer a wide range of water permeability. In this article, we review the mechanisms that ensure water homeostasis as well as the fundamentals of disorders of water balance.

Measurement of thirst in chronic heart failure- a review

Abstract Background: Thirst is a bothersome symptom of chronic heart failure (CHF) which impacts adversely on quality of life. Despite this, limited work has been done to investigate thirst as a symptom or to develop reliable and valid measures of thirst in CHF. The purpose of this manuscript is to establish which tools have been used in research to measure thirst in CHF. Methods: Medline, PubMed, CINAHL, and Scopus were searched using following key words thirst, heart failure, measure, scale, randomised controlled trials and multicentre studies. Results: The search discovered 37 studies of which 6 studies met the inclusion criteria. One study was a research abstract and five were full- text studies. To date, there are only three measurement tools utilised in studies examining thirst in CHF patients (Visual Analogue Scale, Numeric Rating Scale and Thirst Distress Scale). Conclusion: Thirst in CHF is measured in a non- systematic way. In recent studies, the VAS has been used to measure thirst intensity. While this measurement tool is very easy and quick to administer, using a uni-dimensional tool in conjunction with a multi-dimensional tool may be beneficial to capture all dimensions of thirst. In order to manage thirst efficiently, consistent measurement of thirst in CHF is vital.

Thirst trajectory and factors associated with persistent thirst in patients with heart failure

BACKGROUND

Thirst is often increased in patients with heart failure (HF) and can cause distress during the course of the condition. The aim of the present study was to describe the trajectory of thirst during an 18-month period and to identify variables associated with persistent thirst in patients with HF.

METHODS AND RESULTS

Data were collected from 649 patients with HF with the use of the Revised Heart Failure Compliance Scale at 1, 6, 12, and 18 months after a period of hospital treatment for worsening HF. Thirst trajectory was described for the 4 follow-up visits and logistic regression analysis was used to identify factors independently associated with persistent thirst. In total, 33% (n = 212) of the patients reported thirst on ≥1 occasions and 34% (n = 46) continued to have thirst at every follow-up visit. Nineteen percent (n = 121) of the patients had persistent thirst. Patients with persistent thirst were more often younger and male and had more HF symptoms. Higher body mass index and serum urea also increased the risk of persistent thirst.

CONCLUSIONS

Patients with HF who were thirsty at the 1-month follow-up were more often also thirsty at subsequent visits. Assessment of thirst is warranted in clinical practice because one-fifth of patients suffer from persistent thirst.

An intelligent flow control system for long term fluid restriction in small animals

Fluid retention is one of the most common symptoms in patients with chronic heart failure. Although fluid restriction may be a therapeutic strategy, the degree of fluid restriction necessary for the best therapeutic outcome remains unknown partly due to the lack of proper experimental method to restrict water consumption in small animals. The traditional methods that allow animals to access water only in a limited time window or within pre-determined daily volume can be stressful because the animals may become thirsty during the time of water deprivation. To provide a less stressful water restriction paradigm, we designed a feedback-control system of drinking flow to modulate the drinking behavior of small animals. This system consisted of an infrared droplet sensor for monitoring the drinking flow and a computer controlled electric valve to regulate the water availability. A light signal which synchronized with the command for opening the valve was set to establish a conditioned reflex. An animal test indicated that rats were adaptable to a precisely programmed water supply. This system may warrant investigation into the consequences of fluid restriction in chronic experimental animal study.

Thirst response to acute hypovolaemia in healthy women and women prone to vasovagal syncope

The present study measured self-perceived thirst and plasma angiotensin II (ATII) concentrations during graded hypovolaemic stress, induced by lower body negative pressure (LBNP), to elucidate the dependence of thirst on haemodynamics. A total of 24 women aged between 20 and 36 (mean age, 23) years rated their thirst on a visual analogue scale, graded from 0 to 100, when LBNP of 20, 30 and 40 mmHg was applied. Half of the women had a history of vasovagal syncope (VVS). The results showed that the thirst score increased three-fold when LBNP was applied, from 11 (median; 25th-75th percentiles, 9-25) to 34 (27-53; P<0.001). The women in the VVS group had twice as great an increase as those without a history of VVS (P<0.02). The plasma ATII concentration increased significantly in response to LBNP, both in the VVS group and in the control group, but the changes did not correlate with thirst. Application of LBNP decreased systolic and mean arterial pressures, cardiac output and pulse pressure (P<0.001 for all), but thirst correlated only with increase in heart rate and, independently, with reduction of mean arterial pressure. In conclusion, thirst and ATII increase in response to hypovolaemic stress, but are not statistically related. The haemodynamic parameter that was most strongly related to thirst was tachycardia.