Hydration

Assessing hydration in a patient

A popular OSCE question. Which makes it surprising that it's always such a surprise, maybe because - Surprise! - we've never been taught it.

Situations where assessing the fluid status is important eg dehydration:-
-Vomiting
-Sepsis
-Bowel obstruction
-Bleeding
-Recent Surgery
-Diarrhoea
-Fever

Causes of fluid overload:-
-Right heart failure
-Constrictive pericarditis
-Hypoalbuminaemia

Anyhoo - how to assess someone's hydration status, whether dehydrated or fluid overloaded:

General Inspection
I'm looking at the environment to see if there are any important clues into the patient's fluid status. This includes
-fluid restriction,
-drugs
-drips
-lines
-catheter bags,
-or nutritional supplements.

I am then looking at the patient to see if there is any obvious signs of them being
-dehydrated
-or fluid overloaded, e.g. oedema.

Hands
Starting with the hands I am
-feeling them
-and testing the capillary refill to see if there are signs of peripheral shutdown.
Dehydration would be indicated if the cap refill was prolonged.
Normal <2s.

Wrist
I am palpating the
-pulse.
Both dehydration and fluid overload would cause a tachycardic pulse.

Arm
I am testing
-the blood pressure,
-both sitting and standing.
If there was a decrease in the pressures this could indicate dehydration.

Wait 3 minutes between sitting and standing.
Fall in >20mmHg Systolic or >10mmHg Diastolic = Postural Hypotension

Neck
I am looking at the patient's neck to assess
-the JVP, as its height is an indicator of intravascular volume.
Normal = 2cm above sternal angle

If it is diminished, this indicates dehydration.
If it is raised it can indicate fluid overload.

Face
I am looking at
-the eyes, to see if there are sunken orbits. This can indicate moderate to severe dehydration.
I am also looking in
-the mouth to see if there is a lack of moisture, which indicates dehydration.

Chest
Looking at the chest, I am assessing
-the skin turgor by pinching a fold of skin at the sternum (this could also be done on the forearm) for a few moments and then releasing it.

If the skin resumes its place quickly the skin turgor is normal, but if takes a longer amount of time the skin turgor is reduced, and this indicates dehydration.
NB This test, however, is of less use in the elderly when there is loss of skin elasticity.

Oedema
I am checking
-the sacral region
-and legs for signs of oedema, and therefore fluid overload.

Auscultation
I am listening to
-the lungs for the presence of fine inspiratory basal crackles, which could indicate pulmonary oedema
-additional heart sounds to indicate a hyperdynamic state

And to finish off...
I'd like to check the patient's
-temperature
- obs chart (temperature, BP, O2 sats, pulse, RR)
-urine output/catheterise
- fluid balance chart
Inputs (IV fluids, oral intake)
Outputs (urine, stool, drains, stoma bags etc) - vomiting? diarrhoea?
- drug chart – is patient on any diuretics?
- notes - recent surgery?
- further Ix i.e. U&Es, FBC, central line monitoring