HF is a terminal outcome of many cardiovascular diseases . Effective fluid management is a principal way for HF treatment and care . Body weight, urine volume and net fluid balance are considered to reflect the dynamic changes of fluid in vivo [1, 2, 12]. However, it is a hard challenge to obtain an accurate net fluid output and a series of body weight changes both in hospital and at home every day [14, 25]. In this study, we simplified the fluid intake and output recording scheme that was much easier than the professional mode for the self-management of HF patients, and it was also efficient to monitor clinical stability and electrolyte balances. Therefore, this simplified fluid recording scheme might effectively help HF patients improve the quality of life, reduce the recurrent hospitalization times, and especially enhance the feasibility of self-management.
Given the decreased activities of endurance and the difficulties of changing positions from recumbent to standing, monitoring weight daily is often rejected by HF patients. In addition, the accuracy of body weight measurement was also interfered by many factors . Furthermore, as one of the common markers to assess congestion, daily weight loss has no direct relationships with fluid loss and symptom improvement [27, 28]. Thus, only monitoring body weight hardly reflect the daily fluid balance.
Measuring fluid intake and output has long been supposed to be precise and normative. However, it is hard to carry out owing to the low self-management abilities and the complexities of counting fluid intake and output for HF patients . These patients often forget to record fluid intake, reduce the cooperation to collect urine and stool, and ignore to count the fluid contained in foods (such as fruits and vegetables) . In many cases, HF patients are educated to regularly measure fluid intake and output following the textbook disciplines. However, these patients often encounter the changes of lifestyle and physiological state, including bedridden with weakness, urea incontinence and so on. Therefore, this study simplified the professional recording scheme, defining fluid intake and output as net fluid volume. In contrast to the professional mode, it is easier to be manipulated and followed by HF patients. And it did not change the clinical stability and increase the disorders of electrolyte in HF patients. The body weight and NT-proBNP also presented no significant difference (P > 0.05). Some studies also showed that non-dogmatic recording schemes does not cause other adverse results .
Researchers recommended that severe HF patients should moderately restrict fluid, including no more than intaking 1,500–2,000 ml of water, and over 500 ml of additional net output every day [1, 9, 12]. Generally, healthy subjects intake fluid about average 1,500 ml/day in normal conditions. However, the body actually need about 2,500 ml of water to maintain the physical functions. The additional 1,000 ml of water is acquired from “embedded water” (150 ml) contained in foods and “generated water” (750 ml) from food metabolism which is produced from tricarboxylic acid (TCA) cycle and oxidative phosphorylation processes (mainly carbohydrate and fatty acids) (13). The fluid output include: urine about 1,400-1,500 ml/day, feces about 100–200 ml/day, and insensible loss about 800–900 ml/day (e.g. perspiration and evaporation through skin, and water vapor expired to air through lungs) . Coincidentally, the content of water in food is close to that of feces plus insensible loss from skin and lungs. Therefore, when we monitor fluid intake and output in HF patients, we could almost ignore the fluid intake from foods and the fluid output from feces and insensible loss.
Frankly, there are several limitations in the present study. First, this study was performed in a single center, and a hospital-specific bias could not be excluded. Second, this study just observed the changes of HF patients in hospital, but not at home. We hope SRG patients could also adaptively record their net fluid intake and output as a part of his/her daily lifestyle every day. Third, more importantly, we wonder whether this simplified fluid intake and output records together with monitoring body weight could really improve the quality of life and reduce the hospitalization times in these patients for a long time. And we are proceeding a follow-up procedure now.