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Assessing fluid balance

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VOL: 97, ISSUE: 06, PAGE NO: 11

Mandy Sheppard, RGN, is a training and development consultant, Kent

The onset of continence problems can be a gradual process, and patients may be too embarrassed to seek immediate help. This means that any associated fluid imbalance could be relatively long-standing by the time it is first assessed.

The physiological signs of acute fluid imbalance, such as a tachycardia accompanied by hypotension, may be absent, particularly in younger people where compensatory mechanisms are intact and effective. For this reason the assessment of people with continence problems should emphasise visual observations and meticulous history-taking, using effective questioning and listening techniques.

In acute settings, where changes usually occur over a shorter period of time, it is easier to establish a cause-and-effect relationship by piecing events together in a chronological order. This is far more difficult when changes occur over a longer period, as the number of variables and influencing factors multiply.

It may be necessary to assess the fluid balance of patients with continence problems as part of their continence management or because they have presented with a separate medical condition. This could include the following:

- Complaints caused by, or which develop as a result of, continence problems, such as an electrolyte imbalance;

- The causes of the patient’s continence problems, such as a genitourinary disorder;

- An aggravating or exacerbating factor, such as coughing as a result of a pulmonary disorder;

- A condition that is aggravated by the patient’s continence problems, such as a skin condition.

To get a complete picture, any assessment must be broad yet thorough and be founded on a good clinical knowledge base.

Many patients are extremely embarrassed about their continence problems and may be unable or reluctant to discuss them. Nurses must be responsive to these anxieties, and interpersonal skills are vital because a history is one of the main elements of a fluid-balance assessment.

Older patients with a fluid imbalance present additional challenges when it comes to assessment. The physiological changes associated with ageing, such as decreases in their glomerular filtration rate, ability to concentrate urine, thirst sensation and aldosterone secretion, affect older patients’ ability to withstand changes in fluid balance.

In addition, two important assessment tools are invalid in many older patients. The first is skin turgor, which is not reliable when the patient’s skin has lost its elasticity. The second is the assessment of mucous membranes in older people, which may be dry as a result of decreased salivation rather than a fluid deficit.

History-taking is a key part of any fluid-balance assessment. For this reason and because any situation in which patients are unable to provide information - either because of speech difficulties, confusion, disorientation or depression - the help of carers may be required and it may be necessary to use alternative methods of communication.

Fluid loss or gain factors

A range of factors could precipitate either fluid loss or fluid gain. During the history-taking, any of the following conditions should be noted and explored:

- Fluid loss as a result of inadequate intake - this may be caused by nausea, gastrointestinal complaints, social circumstances, confusion or conditions such as arthritis or a cerebrovascular accident, which can make it physically difficult to eat or take fluids. Older people may also restrict their fluid intake in an attempt to alleviate continence problems or because mobility problems make it difficult for them to get to a toilet;

- Excessive fluid loss as a result of vomiting, diarrhoea, increased insensible losses or the excessive use of laxatives or diuretics;

- Fluid gain associated with renal, cardiac or hepatic insufficiency or excess sodium in the diet or in medications.

Visual assessment

During conversation, is the patient constantly trying to moisten his or her lips? This may be a sign of dry mucous membranes caused by fluid deficit.

Nurses should also assess the patient’s skin turgor, as a loss of elasticity may indicate a fluid deficit, but remember that this may not be a reliable method of assessment for older patients.

In the absence of any other causative factors, such as low plasma-albumin levels, peripheral oedema may indicate fluid overload.

Clinical signs

Postural hypotension may become evident when the patient moves from a lying to a standing position. To be significant and to suggest fluid depletion, a drop of at least 15mmHg will be noted in the systolic pressure, with a drop of 10mmHg in the diastolic pressure.

Serial bodyweights are an accurate method of monitoring fluid status. If patients are able to weigh themselves regularly at home these measurements may be used for review, but nurses must ensure that they use the same scales, wear the same amount of clothing and weigh themselves at the same time every day.

Patients who are not steady on their feet may have difficulties weighing themselves, and those with poor eyesight may not be able to see the reading. In such cases, patients can be weighed during regular appointments or clinic visits.

It is also important to ensure that no other changes that could affect their weight have taken place - for instance, as if they have started diuretic therapy.

The time it takes for a patient’s peripheral veins to refill is also a reliable test of fluid deficit. The end of the vein nearest the toes should be occluded with finger pressure and the vein then emptied by stroking it in the direction away from the occluding finger.

Once the vein has emptied and appears flat, the finger pressure should be released, allowing blood to flow into the vein from the direction of the toes.

If the patient is well hydrated, the vein should fill almost immediately. If the patient’s fluid levels are depleted, the vein will fill slowly, usually taking more than three seconds to do so.

Fluid history

If patients cannot provide an accurate history of their fluid balance it may be useful if they or their carers maintain a diary of their dietary and fluid intake.

Output can be more difficult to evaluate. For patients with urinary continence problems who are not catheterised or do not use a penile sheath the number of pads used daily may provide useful information. It may, however, be necessary to weigh them to estimate urinary output.

Assessment strategies

Many patients have difficulties discussing their continence problems, so to take a thorough history nurses must be able to gain their confidence. Even before patient contact, a number of factors should be considered.

The nurse may be the first person the patient has told about his or her continence problem and may have been preparing to do so for some time. If the setting is a local clinic or practice, the patient may be concerned about being seen by friends or neighbours.

Discretion is important, so the history should be taken in a private area where conversation cannot be overheard. In addition, an appropriate assessment technique, using open or leading questions, will yield more than asking a series of closed questions.

Listening skills are also vital: simple techniques such as making eye contact and nodding suggest that the nurse is listening and interested.

Sufficient time should be allocated to take the history. Patients can sense if the nurse is hurrying or seems preoccupied and interruptions should be kept to a minimum. A series of interruptions sends a clear message that the nurse does not take the problem seriously, so ensure that an engaged sign is on the door, the telephone has been diverted and any bleeps have been silenced.

Body language can inadvertently create a misleading impression and, if possible, barriers such as desks should be removed. Many patients are afraid that their continence problem is producing an odour. Sitting too close to them may be intimidating, but sitting too far away can reinforce this perception.

Nurses should also be alert for any non-verbal cues. Men may feel awkward discussing their continence problems with a woman, and cultural influences may need to be considered. As always, nurses should avoid jargon and use plain language.

Conclusion

Assessing fluid balance is an extremely important part of the overall management and care of patients with continence problems. It also allows nurses to combine their interpersonal and communication skills with clinical knowledge, providing the best possible care.

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