Analysis

Alarm bells raised over the effect of dehydration on nurses’ care

More research is needed to assess long-term damage caused by dehydration, say experts in the wake of a study involving nurses and doctors that show almost half of them were dehydrated at the end of a shift.

The study by scientists at the University of Nottingham faculty of medicine and health sciences found a link between dehydration and cognitive function, which could potentially affect performance and patient safety.

Existing research – published in the Journal of the American College of Nutrition (2012) and Clinical Nutrition (2015) – shows that dehydration of just 2% of body weight may impair physical and cognitive performance. Dehydration can lead to kidney damage, constipation, dental and respiratory problems.

The latest study asked 88 nurses and doctors working on medical and surgical wards at a university teaching hospital to undergo tests assessing levels of dehydration before and after a shift, and the effect on their cognitive function.

Access to water

More than one third – 36% – were dehydrated at the start of their shift. Throughout the shift a further 9% became dehydrated, resulting in 45% failing to have enough to drink by the time they finished work.

RCN senior employment relations adviser Kim Sunley says the research highlights the problems nurses have taking breaks when they work excessive hours with too few staff.

‘It is a matter of time rather than access,’ she says. ‘Most wards and units will have a kitchen area. It’s the age-old issue of having adequate staff so that nurses can take five minutes out to rehydrate.

‘Employers have a legal duty under workplace regulations to provide access to drinking water. If nurses don’t have access to it – or are not given the time to have access to it – then employers are in breach of that regulation.

‘There are also patient safety implications if cognition is affected. It is in the organisation’s interests to do more.’

Participants in the research were asked to turn up 20 minutes before their shift started when their blood and urine were tested and their height and weight measured.

Their cognitive function was also tested before and after the shift using computer-based tests – the Stroop Colour Naming Interference Test and Sternberg Memory Paradigm. Results shows an association between dehydration and impaired cognitive function, although a direct link could not be made says University of Nottingham clinical research fellow Ahmed El-Sharkawy, one of the research authors.

‘In certain cognitive tests those who were dehydrated had a greater number of errors – a median difference of one error,’ he says.

Kidney injury risk

Participants in the study worked as usual though their shift, but were asked to keep a fluid diary and measure intake and output of fluid using scales. Using four separate measures of hydration helped to validate results in an area of research where no clear measure currently exists.

‘One of the difficulties of this area of research is that there is not a gold standard to measure hydration. But this measure of osmolality is reasonable,’ says Mr El-Sharkawy.

The results show that almost half the participants were dehydrated at the end of their shift and 41% were oliguric.

‘If they were patients on our ward I would say they were at risk of kidney injury and it was worrying,’ says Mr El-Sharkawy.

Participants were also asked to use a laptop and remember five numbers while other random numbers and letters were flashed on to the screen. ‘It is not the most sensitive test. It is crude and it’s not the real world,’ says Mr El-Sharkawy. ‘But these were healthy, cognitively sound generally young individuals. So you would not expect them to make those mistakes.

Principal study findings

Of the 88 doctors and nurses who completed the study over 130 shifts:

36% were found to be dehydrated at the start of their shift.

45% were dehydrated at the end of the shift.

Mean (SD) urinary osmolality was significantly greater at the end of the shift when compared with the start (720 [282] vs 622 [297] mOsm/kg, p = 0.031).

41% were oliguric at the end of the shift.

Single number and five-letter Sternberg short-term memory tests were significantly impaired in dehydrated participants (p< 0.05).

‘There was one mistake difference on average on one task. Over the course of the day they may be doing many tasks.’

Loughborough University emeritus professor of sport and exercise Ron Maughan says headaches and poor concentration are linked with dehydration. ‘Even modest levels of dehydration can have that effect,’ he says. ‘We try to avoid that happening and we have a fairly good thirst mechanism. But we can ignore our thirst and consciously override it.’

He compares nurses to commuters who deliberately don’t drink at breakfast because they know the trains do not have toilets on board. ‘There is possibly a concern over the need to go to the bathroom at a time that might be inconvenient,’ he says.

‘That applies in some caring professions because you may be rushed off your feet or you don’t want to be in a situation where you are not focused on the job in hand because you need to go to the bathroom.’

Picture credit: Alamy

European Hydration Institute (EHI) director Jane Holdsworth says more training is needed for healthcare professionals to understand the implications of dehydration. Although basic information is covered as part of existing training, nurses could benefit from more in-depth understanding about the signs and risks, she says.

EHI is developing an online course that will give nurses the opportunity to refresh their knowledge on hydration. ‘We are in the process of setting up four online courses covering general water and hydration, perioperative hydration, hydration for people who are physically active and hydration for people in care homes.

‘They will be small stand-alone modules that people in those areas can complete to bring them up to speed on hydration.

It’s the age-old issue of having enough staff so nurses can take time out

– Kim Sunley

‘The general water and hydration module focuses on the basics – why hydration is important, how we hydrate and what happens to the water in our bodies. That is applicable to anyone and to healthcare professionals too.’

Modules, which should be available on the EHI website by the end of the year, are free and may carry credits for continuous medical education.

While there has been some work on the short-term effects of dehydration, possible long-term damage has not been clearly identified, says Professor Maughan.

‘We need a lot more information in this area,’ he adds.

‘The issue of hydration has been under-researched over the years perhaps because people don’t think it is anything of any great importance’.

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