Fluid Assessment

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Fluid Assessment

Inspection

• Look around the bed for clues. e.g. fluid restriction signs, catheter bag, nutritional supplements

• Look at the face for sunken orbits – this is a sign of moderate to severe dehydration

• Look inside the mouth – look at the tongue and mucous membranes for signs of moisture. Dehydration will cause these surfaces to appear dry

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Fluid Assessment - Palpation

• Skin turgor. Gently pinch a fold of skin on the forearm, hold it for a few seconds, then let go.

• Normal hydration – the skin will promptly

return to its original position

• Dehydration – the skin will take longer to

return to its original position

• This sign is unreliable in elderly patients – as these people tend to have lost their natural skin elasticity anyway

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Fluid Assessment – Palpation (2)

• Capillary refill – raise the patient’s hand to the level of the heart, then press down hard on the nail for 5 seconds. Note the time taken for the normal pink colour to refill. If this takes longer than 2 seconds it indicates poor peripheral blood supply

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Fluid Assessment – Palpation (3)• Pulse – there may be a compensatory tachycardia in both dehydration

and fluid overload• Blood pressure – check both lying and standing BP. Low standing BP

indicates dehydration(Measure BP with the person either supine or seated. Stand, then measure BP again after standing for a minute

• If = or greater than 20mmHg difference in standing BP• Orthostatic or postural hypotension occurs when there is a sudden and

significant decrease in the systolic and/or diastolic blood pressure when a person stands up. It occurs within three minutes of standing..

• When a person stands, there is about 500–1,000 ml of blood that goes from the upper body to the lower body. In response to this, there are compensatory effects from activation of the SNS , the renin-angiotensin system, and consequent aldosterone release. Homeostatic mechanisms may be inadequate to restore low BP, if myocardial contractility or vascular responsiveness is depressed, as seen in hypovolemia.

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Fluid Assessment – Palpation (4)

• JVP – check the height of the JVP. This is one of the most sensitive ways of judging intravascular volume. JVP will be low in dehydration and high in fluid overload. Fluid overload also commonly causes basal crepitations as a result of pulmonary oedema – so if you suspect fluid overload you should listen to the lung bases.

• Oedema – check both sacral and ankle for signs of fluid overload.

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Fluid Assessment - Auscultation

• Crepitations in the lung bases are present in pulmonary oedema

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Fluid Assessment - Urine

Check the urine.

• darker urine suggesting dehydration

• Urine specific gravity is a slightly more accurate way of measuring hydration as it measures the concentration of solutes in the urine. The greater the concentration, the greater the degree of dehydration.

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Fluid Assessment - Bloods

• Sodium levels in the blood become abnormally high when water loss exceeds sodium loss, as in dehydration. • Normal plasma sodium levels are between 136 and 145

mEq/litre.

• Elevated urea with a normal creatinineconcentration will occur in dehydration, as there is increased reabsorption of urea and not creatinine by the kidneys.• In dehydration, the ratio of urea to creatinine

is elevated from a factor of 10 to a factor of 20.

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Fluid Assessment

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Signs of Fluid Overload

• High Blood Pressure

• Increase in Weight

• Oedema

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Signs of Dehydration

• Low BP

• Decreased skin turgor

• Dry mucosa

Summary

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