AIMS

•       Understand normal fluids electrolyte requirements/ maintenance

 

•       Understand how to assess DEHYDRATION in children

 

•       Understand the difference between DEHYDRATION and SHOCK but that they may occur together

 

MAINTENANCE FLUIDS

RCH FLUID CALCULATOR

 

Fluid & Electrolytes
Normal Fluid Requirements

INSENSIBLE LOSSES

•        Caloric content of feeds

•        Ambient temperature

•        humidity of inspired air

•        Fever

 

 

•        Stool output usually between 0 -10 ml/kg/day are lost in stools (may exceed 300 ml/kg/day in diarrhoea)

•        Urinary output usually between 1-2 ml/kg/hour

 

Fluid & Electrolytes
Normal Electrolyte Requirements

DEHYDRATION

 

A condition caused by the excessive loss (deficit)  of water from the body

 

DEGREE OF DEHYDRATION

What are the symptoms and signs of dehydration?

 

 

How do you distinguish MILD v MODERATE v SEVERE dehydration?

WEIGHT

•       Weigh bare child and compare with any recent (within 2 weeks) weight recordings

 

•       The best method relies on the difference between the current body weight and the immediate pre-morbid weight.

 

 

MILD DEHYDRATION <4%

•       No clinical signs

 

•       They may have increased thirst

 

•       They will have a history of losses eg vomiting, diarrhoea, increased insensible losses

 

–   DOCUMENT FREQUENCY/ VOLUME/ DURATION OF LOSSES

MODERATE DEHYDRATION 4-6%

•       HISTORY OF LOSSES +/ DECREASED URINE OUTPUT 

 

•       Central Capillary Refill Time> 2 secs

•       Increased respiratory rate

•       Mild decreased tissue turgor

•       Sunken eyes, fontanelle

•       Dry mucous membranes

SEVERE DEHYDRATION > 7%

•       HISTORY OF LOSSES, decreased urine output +/- lethargy

 

•       CRT > 3 secs

•       Mottled skin

•       Decreased tissue turgor

•       Other signs of shock

–   Tachycardia

–   Neurological:  irritable or reduced conscious level,

–   Hypotension

•       Deep, acidotic breathing

 

Considering fluids:

Degree of dehydration (deficit)
+

Maintenance fluid requirements
+

Ongoing losses

 

Calculate deficit

•       Degree of dehydration expressed as % of body weight

 

–   e.g. a 10kg child who is 5% dehydrated has a water deficit of 500mls

 

–   WEIGHT X DEFICIT % X 10 (in ml)

 

–   = 10 X 5 X 10 = 500 ML

 

•       The deficit is replaced over a time period that varies according to the child's condition. Precise calculations (eg 4.5%) are not necessary

 

•       The rate of rehydration should be adjusted with ongoing assessment of the child.

Speed of replacement

•       Replacement may be rapid in most cases of  gastroenteritis (best achieved by oral or ng fluids)

 

•       SLOWER in DKA, meningitis and HYPERNATRAEMIA

–   In Hypernatraemia aim to rehydrate over 48 hours with Na not falling more than 1mmol/litre/hour

SHOCK

Shock occurs as result of rapid loss of 20 mL/kg from the intravascular space

 

SHOCK

 

•       The treatment of shock requires rapid administration of a bolus of intravascular fluid (start with 10- 20ml/kg then reassess) with electrolyte content that approximates to plasma (eg. 0.9% saline)

 

•       If the intravascular volume is maintained, clinical dehydration is only evident after losses of >25 mL/kg of total body water.

 

 

DEHYDRATED BUT NOT SHOCKED

 

•       The treatment of dehydration requires gradual replacement of fluids, with electrolyte content that relates to the to the electrolyte losses, or to the total body electrolyte content.

RATE OF REPLACEMENT

•       RCH Gastroenteritis

•       Aim for ENTERAL replacement if possible

•       PO

–   Ondansetron if >6m/ >8kg

–   10-20ml/kg over an hour of ORS

•       NG

–   Ondansetron as above

–   BHS we do SLOW rehydration

NG fluid replacement

•       Replace deficit over first 6 hours and then give daily maintenance over the next 18 hours. To calculate hourly rate

 

•       TABLE 3 of the RCH gastroenteritis

IV FLUIDS

•       NG is safer and more effective but IV rehydration is indicated for severe dehydration and if NG fails (eg. ongoing profuse losses or abdominal pain)

 

•       Also suitable for children who already have an IV insitu

 

•       Certain comorbidities, particularly GIT conditions (eg. short gut or previous gut surgery) - discuss these patients with senior staff.

IV fluid choice (not shocked)

•       Rapid IV Rehydration (d/w senior)

–   In older children > 4 years

–    moderate dehydration with no comorbidities, no electrolyte disturbance and no significant abdominal pain

–   10 ml/kg/hr (up to 1000ml/hr) for 4 hours  0.9% sodium chloride (normal saline) and 5% Glucose, then reassess.

Standard IV Rehydration for the first 24 hours.

•       Table 4 RCH guideline

•       Table 4

IV FLuids

•        0.9% sodium chloride (normal saline) and 5% Glucose for rehydration after any required boluses.

–   If serum K < 3mmol/L, add KCl 20mmol/L, or give oral supplements

 

•       Measure Na, K and glucose at the outset and at least 24 hourly from then on (more frequent testing is indicated for patients with comorbidities or if more unwell)

 

•       Plasmalyte 148 is used in ICU at BHS

 

Monitoring

•       Bare weigh patient 6 hourly in moderate and severe dehydration, who are receiving NGTR or iv fluids

 

•       Carefully reassess after 4-6 hours, then 8 hourly to guide ongoing fluid therapy – this should be part of morning & afternoon handover

 

•       Look particularly for:

–   weight change

–   clinical signs of dehydration

–   urine output

–   ongoing losses

–   signs of fluid overload, such as puffy face and extremities.

FLUIDS

•       Understand maintenance requirements

•       Understand assessment of dehydration

•       Differentiating dehydration v shock v dehydration & shock

•       Fluid replacement

–   Po

–   Ng

–   Iv fluids