15 dehydration

Fluid therapy in dehydration

Dr Ngugi

How severe is the dehydration?

Cold Hands plus, weak / absent pulse, and one of: Capillary refill > 3 secs Not alert, AVPU < A

ShockY

How severe is the dehydration?Cold Hands plus, weak / absent pulse, and one of: Capillary refill > 3 secs Not alert, AVPU < A

Pulse easy to feel, but unable to drink or AVPU < A plus:

Sunken Eyes

Skin pinch ≥ 2 secs

Shock

Severe Dehydration

Y

Y

How severe is the dehydration?Cold Hands plus, weak / absent pulse, and one of: Capillary refill > 3 secs Not alert, AVPU < A

Pulse OK but unable to drink plus:Sunken EyesSkin pinch ≥ 2 secs?

Able to drink plus ≥ 2 of:

Sunken Eyes and / or

Skin pinch 1 - 2 secs

Restlessness / Irritability

Shock

Severe Dehydration

Some Dehydration

Y

Y

Y

How severe is the dehydration?Cold Hands plus, weak / absent pulse, and one of: Capillary refill > 3 secs Not alert, AVPU < A

Pulse OK but unable to drink plusSunken EyesSkin pinch ≥ 2 secs?

Able to drink plus 2 or more of:Sunken Eyes and / orSkin pinch 1 - 2 secsRestlessness / Irritability

Shock

Severe Dehydration

Some Dehydration

Not classified above? No Dehydration

Y

Y

Y

Y

Why do we use these signs?• Shock requires immediate management• The ability to drink is an important indicator of

severity. If they can drink then use oral or oral + ngt fluids.

• Sunken Eyes and Skin Pinch are the most reliable signs of dehydration

• Signs which work poorly include:– Dry mucous membranes– Absence of tears– Poor urine output

Treating Shock / Severe Dehydration

• The greatest concern is the loss of fluid from the circulation.• To restore circulation the fluid replaced at first needs, ideally, to be like plasma

Sodium, Na+ 140 mmol/l

Potassium, K+ 4.0 mmol/l

Which common iv fluids have a similar composition to plasma?

All concentrations are in mmol/l Na+ K+

Plasma 140 4.0

Normal Saline (0.9%) 154 0

Ringer’s Lactate(Hartmann’s)

130 5.4

Use of low sodium content fluids

Na+, 140 mmol/l

Exi

stin

g flu

id

Fluid deficitIf the fluid deficit is first replaced with a low sodium fluid then body sodium is diluted.

These low sodium fluids are much less good at restoring the circulation and can cause hyponatraemia leading to convulsions

Low sodium concentration fluids that should not be used to correct shock or severe

dehydration unless there is severe malnutrition

All concentrations are in mmol/l

Na+ K+

Half Strength Darrow’s (& 5% Dextrose) 61 17

Low sodium concentration fluids that should not be used to correct shock or severe

dehydration in any situation.

All concentrations are in mmol/lNa+ K+

Dextrose (4%) / Saline (0.18%) 31 0

5% Dextrose 0 0

Treatment of hypovolaemic shock

Shock identified Airway & Breathing (oxygen) effectively managed

Establish iv / io access

20 mls / kg bolus of fluid (<15 mins)

Re-assess clinical signs of shock

Signs persist

Treatment of severe dehydration without shockFull Strength Ringers(Normal Saline if unavailable)

Age < 12 months Age ≥ 12 months to 5 years

Phase 1 30 mls / kg over 1 hour

30 mls / kg over 30 mins

Phase 2 70 mls / kg over 5 hours

70 mls / kg over 2.5 hours

Then re-assess child – if still signs of severe dehydration repeat step. If signs improving treat

for some dehydration

This is equivalent to correcting 10% dehydration in 3 – 6 hours

Re-assessmentCold Hands - Weak (absent) pulse - Prolonged capillary refill?Reduced level of consciousness?Sunken Eyes / Slow skin pinch

Pulse OK but unable to drink plusSunken EyesSkin pinch ≥ 2 secs?

Able to drink plus 2 or more of:Sunken Eyes and / orSkin pinch 1 - 2 secsRestlessness / Irritability

Shock

Severe Dehydration

Some Dehydration

Not classified above? No Dehydration

Y

Y

Y

Y

Some dehydration is best treated with ORS

• Oral rehydration (by mouth or ngt) works just as well as iv rehydration.– In one detailed review of >1500 children deaths

and convulsions were fewer in the orally treated group than in the iv treated group.

– If the rate of drinking is not adequate ORS can safely be given down an ng tube.

How much to give?

• ORS ++• ORS plenty• Frequent ORS• ORS until better

Prescribing ORS

• 75 mls / kg of ORS over 4 hours.• After 4 hours reassess and reclassify;

– Severe, Some or no dehydration?

Counseling the mother / caretaker?

• What do you tell the mother of an 8kg child?

ORS in practice.

300 mls 200 mls

Prescribing ORS

• 75 mls / kg for an 8kg child?

– 600 mls in 4 hours– 2 large cups / 2 soda bottles in 4 hours– 3 small cups in 4 hours.

Vomiting and feeding?• Vomiting is NOT a contra-

indication to oral rehydration• Careful counseling about, slow,

steady administration of ORS is helpful.

• Breast feeding and other forms of feeding can and should continue during diarrhoea and oral rehydration.

• There is no evidence of benefit from using half-strength feeds or gradual re-introduction of feeding.

Role of antibiotics & Zinc.• Diarrhoea / dehydration do not require antibiotics

if that is the only problem.• But if a child is shocked or has signs of another

severe illness then treat with antibiotics appropriate for shock or the co-existing problem.

• Bloody diarrhoea is treated with Ciprofloxacin.• Zinc should be given to all children with diarrhoea

as it speeds resolution of symptoms:– 10mg od (half tab) for 14 days if age <6 months– 20mg od (one tab) for 14 days if age >=6 months

Questions?

Summary

• A small number of signs are most useful in classifying the severity of dehydration.

• Shock & severe dehydration must be treated using fluids with physiological sodium concentrations.

• Classify severity, treat by specifying fluid, the volume needed and the time to give it in.

• Then reassess.