Clinical assessment of fluid balance

A history of the client’s recent fluid input and output along with any particular difficulties related to their fluid balance needs to be obtained. This must recognise planned and future interventions that will affect intakes. For example when a client is nil by mouth for

surgery and certain procedures, they will not be able to eat and drink. Treatments such as chemotherapy or extensive head and neck surgery will obviously impact on their fluid intakes. Interventions will therefore be needed to overcome any potential fluid imbalance that may occur. There are a number of vital signs that can be used to assess and monitor a client’s fluid balance. These include the monitoring of fluid input and output alongside laboratory findings and weight.

Table 6.4 summarises the key means of determining a client’s fluid status.

Fluid input and output charts

This is a common means of monitoring fluid balance and can act as an important part of the assessment and monitoring process.

The following details how a fluid balance chart should be maintained:

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The registered nurse or other registered practitioner to determine the need for a fluid balance chart. All clients receiving IV fluids should be given a fluid balance chart.

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Inform the client, their carers and all other staff involved in the care about the fluid balance chart.

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Measure intake from all sources, i.e. oral fluids, IV fluids, enteral feeds (including water used to flush the tube), fluid medication and liquid food (e.g. soup).

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Accurately measure output from all sources, i.e. urine output (bedpan, urinal or catheter), nasogastric drainage, drainage tubes, diarrhoea, wound drainage and vomit.

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Record input and output on the chart.

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At the end of each 24-hour period, total the client’s input and output values. Higher input values compared to output values indicate a positive fluid balance, whereas lower input values compared to output values indicate a negative fluid balance.

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Weigh the patient daily at the same time and in the same clothes. Sudden and acute weight changes are indicative of fluid gains/losses. One litre of water weighs 1 kg.

These changes can then be assessed against the fluid balance record from each day.

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Significant changes in the client’s input and output need to be reported to the regis- tered nurse and doctor in case further monitoring or intervention is required.

Urine output that falls below 30 mL/hour over two consecutive hours can be indicative of renal failure, internal bleeding or dehydration. Further investigations and treatment would be urgently started if this occurs.

Maintaining fluid intakes

Fluid balance in adults normally comprises of an input of 2400 mL and an output of 2400 mL; however, this can vary from day to day.

Oral intakes

After assessing and determining a client’s needs the most obvious method of ensuring their fluid intake is to give adequate amounts of oral fluids. Many of the issues that relate to ensuring adequate nutritional intakes in practice will also apply to maintaining oral

Table6.4Assessmentoffluidstatus. ObservationFluidexcessDehydration HistoryofrecentfluidbalanceaReducedurineoutput(oliguria) Nourineoutput(anuria) Excessiveurineoutput(polyuria) NB:Oliguria/anuriacanoccurinconditions suchasrenalfailureandwillcauseanexcess offluidinthebody

Reducedurineoutput(oliguria) Nourineoutput(anuria) Excessiveurineoutput(polyuria) Diarrhoea Vomiting Polydipsia(excessivethirst) Excessivefaecalfistulalosses Unabletoeatordrinknormally NB:Oliguria/anuriawillnormallyoccurin dehydratedclients.Howeverconditionssuchas diabetesmellituscanleadtopolyuriaandthatcan causedehydrationifintakeisnotmaintained Afaecalfistulacanoccurwhenatractdevelops fromtheboweltotheabdominalsurfacewhereit oozesfaecalfluid.Thismayoccurafterbowel surgeryorincertaincancers PhysicalassessmentaFirm,protrudingeyeballs Oedema Ascites Boundingpulse Tautshinyskin Sunkeneyeballs Dryandflakyskin Drycrackedmouth Weakthreadypulse (Continued)

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Table6.4(Continued) ObservationFluidexcessDehydration Vitalsignsb Bloodpressure Pulse Temperature Respirations Increased Increased Unchanged Increasedrate

Decreased(especiallyonstanding) Increased Elevated Unchangedorincreased Keylaboratoryfindingsb Urine-specificgravity SerumsodiumDecreased(around1.003) Lessthan135mmol/LIncreased(around1.025ormore) Greaterthan145mmol/L HourlyurineoutputbMorethan60mL/hour NB:normallyhydratedindividualscanhavean outputabove60mL/hour

Lessthan30–50mL/hour NB:thismaynotbethecaseiftheclienthas polyuriaduetodiabetesmellitus Weightb Thismustbeassessedinthe contextofaclient’snutritional status.Acutelossesand increases(overhours/afew days)areusuallyassociatedwith fluidmovement

A5%gainAlossof2–6%mayindicatedehydration aTheseobservationsarebasedonasubjectiveorpersonalviewoftheclient’spresentationandassuchmaynotalwaysbeaccurate. bTheseobservationsarebasedonmoreobjectivemeasurementsandofferamoreaccuratemeansofdeterminingfluidstatus.

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fluid intakes. The RCN and NPSA (2007) have jointly detailed a number of practical tips to encourage water consumption in the clinical areas.

The following are a summary of these tips:

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Develop a policy on water provision and monitoring for patients

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Free fresh water should be available for patients and staff throughout the day

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Use picture reminders for the nursing staff to encourage water intakes

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Use a positive approach with patients to promote them to drink more

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Serve fresh and chilled water. The use of water coolers may be an option and a slice of citrus fruit may help improve vitamin C consumption

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Try a little and often offer water at mealtimes and also between meals. Offer larger volumes of water when giving medication and encourage patients to drink from early in the morning

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Offer water alongside tea and coffee. Hot water with a piece of fruit can appeal to those wanting a hot drink

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Remember older people and those who are sick can lose their thirst response

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Encourage carers and family to promote hydration with the client

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As the weather gets warmer, increase the availability of water and encourage greater intakes

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Identify those at risk of dehydration and those requiring assistance with drinking. Use strategies for confused patients to help them consume water

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Monitor and record fluid intake

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Keep trying – sometimes it takes times and patience

Intravenous therapy

For some clients it will not be possible to maintain an adequate oral intake. In this case IV therapy will be an important means of ensuring adequate fluid intakes. The choice of fluid will be determined by the client’s condition and must be prescribed. There are a variety of IV fluids that are used to maintain electrolyte and fluid balance.Normal saline contains water and the electrolytes sodium and chloride. In this solution, there is specifically 0.9 g of sodium chloride per 100 mL of water. Other solutions contain glucose and water only (sometimes called a dextrose solution since dextrose is another term for glucose). A 5% glucose solution contains 5 g of glucose in 100 mL of water.

There are also other forms of IV fluids that have combinations of glucose and saline and some that contain sodium lactate or sodium bicarbonate. The choice and amount of IV fluid for fluid replacement is dependent on the patient’s condition and will be influenced by their blood results.

There are specific management issues related to IV infusions that are beyond the scope of this chapter.