Adequate hydration for hospital patients has largely been overlooked as an important factor in recovery, partly because there were no official guidelines about requirements
Emma Derbyshire PhD RNutr
Senior Lecturer and Researcher
in Human Nutrition,
Manchester Metropolitan University,
Member of the National Hydration Council
(UK) Scientific Panel
The European Hydration Institute (EHI) has been established with a view to advancing and sharing understanding of knowledge and matters relating to hydration and health.(1) Although much is mentioned about the hydration needs of older people, the importance of hydration in patients in hospital remains an overlooked area.
There is now good evidence that dehydration in hospitals can alter the physical and psychological function of patients, leading to longer hospital stays(2) and poor health outcomes.(3) The role of health professionals is important and can play a key role in preventing, detecting and treating fluid disorders and electrolyte imbalances. Ultimately, this may help towards improving the patients’ healthcare experience, but more importantly, it may help their recovery.
Until recently there has been a lack of guidelines and consensus across Europe as regards hospital hydration. The European Food Safety Authority (EFSA) has recently attempted to plug this gap and has now published Dietary Reference Values for water.(4) Although the values are not yet specific to hospital patients, they provide an important and useful benchmark, which was not available previously.
This paper aims to examine which individuals are at risk of dehydration in European hospitals and how this can affect patient health and recovery. The following sections will also outline and evaluate current methods used to assess hydration status in hospitals and provide up-to-date information about the latest hydration guidelines.
Hospital hydration and health
In hospital environments, suboptimal hydration is not uncommon. There are many reasons for this but improving staff awareness, levels of patient supervision (helping patients to drink fluids) and early diagnosis of oral health problems and other medical disorders, such as dysphagia, may help to improve fluid uptake.(5)
When patients are not adequately hydrated there is evidence that this can lead to higher mortality rates. In one study, patients with higher water intakes (five or more glasses daily) were less likely to suffer a fatal heart attack than patients with lower water intakes.(6)
Older patients, in particular, have a higher risk of dehydration in hospitals when compared with younger individuals. This, in turn, has been linked to higher rates of infection and mortality rates of over 50%. One reason is that older individuals have a reduced thirst sensation and reduced fat-free mass (around 73% water), both of which can lead to poor hydration status.(7)
In recent years, medical evidence has shown that being adequately hydrated can play an important role in preventing and treating certain conditions. For example, adequate hydration is thought to reduce the risk of urinary tract infections and kidney stones as well as diabetes, hypertension, venous blood clots, stroke and coronary heart disease. Poor hydration may also exacerbate the symptoms of pulmonary disorders, such as cystic fibrosis.(8) There is further evidence that proper hydration can help to reduce the risk of pressure ulcers, constipation, low blood pressure and impaired cognitive (mental) performance.(3)
In addition to older hospital patients, other ‘at risk’ groups for developing dehydration are patients with chronic gastric conditions, such as diarrhoea, and those on multiple medications (polypharmacy), which can stress the body’s water and electrolyte balance. Infants and children are also at risk of ‘hypernatraemic dehydration’ – when more salt than water is lost from the body (usually with bouts of vomiting and/or diarrhoea). Although treatment strategies depend on the severity of conditions, oral hydration solutions may be needed to replace both the fluids and electrolytes that have been lost by the body.(9,10)
Signs of inadequate hydration
Identifying patients at risk of dehydration can be difficult, and physical signs, such as dry mouth, lips and eyes, are easily confused with other medical conditions. Some simple signs of dehydration (mild to severe) are shown in Table 1 and can be useful indicators for healthcare practitioners.
Hydration status can also be determined using urine tests, such as urine colour and specific gravity tests. New research, however, has suggested that these may not be the best indicators, particularly when it comes to identifying ‘early dehydration’.(11) Clearly, there is a need for novel methods that are simple, safe, inexpensive, precise, reliable, non-invasive and preferably portable.
One possibility may be testing tear fluid osmolarity.(12) However, further validation studies are needed, particularly on hospital patients, before this can be recommended as a viable method.
Guidance of ‘how much’ fluid people should drink on a daily basis has recently been published by EFSA in the form of ‘Dietary Reference Intakes’.(4) It is, however, important to consider that ‘total fluid values’ (see Table 2) include water from beverages and foods. Examples of foods with a high moisture content include soups, stews, dairy products such as yoghurt and certain fruits and vegetables. These values, also known as adequate intakes, have been derived using data from populations with a desirable urine osmolarity.
It is important to consider that these guidelines are for healthy individuals and that hospital patients may have slightly different needs. Individual requirements can be influenced by factors such as ambient temperature, humidity, poor ventilation, oral health, age and health status.
In the UK, the Royal College of Nursing encourages hospital patients to drink fluids at mealtimes and when medications are provided to patients. It is recommended that they drink around half a litre (500ml) on these occasions, which is the equivalent of approximately 2.5l fluid daily,(13) slightly higher than EFSA guidelines.
Organisations such as the Care Quality Commission have also identified that many hospital patients suffer from dehydration, which has been attributed to a lack of consistent guidance, leadership and staff knowledge about how to assess and maintain patients’ hydration status. It was also proposed that meal times should be more structured and conducted as social events, where patients can be assisted in drinking.(14)
Types of fluids
All non-alcoholic beverages can play a role in restoring fluid losses, but some are regarded as being healthier than others. In the UK, a fluid guide has been produced by the British Nutrition Foundation that rates water as being the first beverage choice, followed by unsweetened tea and coffee, low-calorie drinks and sugar-sweetened beverages.(15) As mentioned previously, foods with a high-moisture content can also help to improve hydration status.
It is also important to consider that encouraging patients to drink more water could reduce operational and patient costs. For example, well-hydrated patients generally recover faster and often use fewer medications than those drinking suboptimal amounts.
Overall, in most European hospitals, water is not yet seen as an ‘essential nutrient’ that can help to support patient recovery. On the whole, the provision of drinking water, appropriate storage and assistance in helping patients to drink sufficiently is largely inadequate. While we have the European Food Safety Authority guidelines, clear hydration policies across European Health Authorities are still lacking. Providing this key nutrient to hospital patients at regular intervals, in a form that is appealing, such as fresh, chilled water rather than tepid water served in jugs, and encouraging and assisting patients to drink fresh water are all matters that can be easily rectified. In turn, these simple changes can have considerable health and economic benefits for European healthcare systems.
Key points for consideration
- Chilled, fresh water should be available to hospital patients throughout their day. Encouraging patients to drink water with meals and when their medications are distributed can help to improve fluid uptake.
- Water should generally be the first beverage of choice but tea (caffeinated and herbal), diluted squash, fruit juices and moisture-rich foods can also help to maintain hydration levels.
- Staff should be enthusiastic about encouraging and helping patients to drink water in appropriate amounts (small and often rather than large volumes).
- Some patients may not feel thirsty or not want to drink water, for example incontinent patients, and they may need to be reminded about the importance of drinking regular fluids.
- Health professionals should also take care to consider patients’ medications and the effect these can have on water balance.
- Urine colour and assessing patients’ physical characteristics are useful indicators of hydration status but advanced, quick, cost-effective and accurate methods are also needed.
- Encouraging patients to drink plenty of water can help to prevent, treat and manage a wide range of medical conditions leading to shorter hospital stays, improved patient wellbeing and reduced healthcare costs.
- European Hydration Institute. www.europeanhydrationinstitute.org/what_is_the_ehi.html (accessed 21 February 2012).
- Suhayda R, Walton JC. Preventing and managing dehydration. Medsurg Nurs 2002;11(6):267–78.
- Aggett K. Nutrition Guidelines for the European Care Industry 2006. www.lidstercorp.co.uk/documents/LiteratureReviews/HealthCareandNutrition… (accessed 21 February 2012).
- EFSA Panel on Dietetic Products, Nutrition, and Allergies. Scientific opinion on dietary reference values for water. EFSA Journal 2010; 8(3):1459–506.
- Amella EJ. Feeding and hydration issues for older adults with dementia Nurs Clin North Am 2004; 39(3):607–23.
- Chan J et al. Water, other fluids and fatal coronary heart disease. Am J Epidemiol 2002;155(9):827–33.
- Holman C, Roberts S, Nicol M. Promoting adequate hydration in older people. Nurs Older People 2005;17(4):31–32.
- Manz F. Hydration and disease. Am Coll Nutr 2007;26(5 Suppl):535S–541S.
- Colletti JE et al. The management of children with gastroenteritis and dehydration in the emergency department. J Emerg Med 2010; 38(5):686–98.
- NHS Choices. Dehydration. www.nhs.uk/conditions/dehydration/Pages/Introduction.aspx (accessed 21 February 2012).
- Rowat A et al. A pilot study to assess if urine specific gravity and urine colour charts are useful indicators of dehydration in acute stroke patients J Adv Nurs 2011;67:1976–83.
- Fortes MB et al. Tear fluid osmolarity as a potential marker of hydration status Med Sci Sports Exerc 2011;43:1590–97.
- Royal College of Nursing. Hospital hydration best practice toolkit 2011. www.rcn.org.uk/newsevents/campaigns/nutritionnow/tools_and_resources/hyd… (accessed 21 February 2012).
- Care Quality Commission. 2011. www.cqc.org.uk/findareport.cfm (accessed 21 February 2012).
- Benelam B, Wyness L. Hydration and health: a review. Nutr Bull 2010;35:3–25.