3928768 fluids and electrolytes
TRANSCRIPT
8/13/2019 3928768 Fluids and Electrolytes
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Fluids and Electrolytes
By
Chirag Jain
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Objectives
Learn to calculate maintenance fluids
Learn maintenance electrolyte needs
Learn the signs and symptoms ofdehydration
Learn to calculate replacement fluids for
isonatremic/hyponatremic/hypernatremicdehydration
Oral Rehydration Therapy
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“Just Start Maintenance”…
Maintenance fluid provide the water andelectrolytes equal to those lost simply forbeing alive and having a basal metabolic rate
Metabolism makes heat and solute that youneed to get rid of to maintain homeostasis – Insensible fluid loss – dissipates heat by evaporation
of water from skin and URT (50% of maintenance
needs) – Soluble waste is excreted in urine (50% of
maintenance needs)
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Some Conversions
1 mL = 1 cc30 cc = 1 ounce
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Calculating Maintenance Fluids
The Holliday-Segar Formula(Burn these numbers into your mind)
100-50-20
4-2-1
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Calculating Maintenance Fluids
The Holliday-Segar Formula
Based on calorie expenditure
1 mL of water needed for each kcal usedWeight (kg) kcal/d or mL/d kcal/h or mL/h
0 to 10 kg 100/kg/d 4/kg/h
11 to 20 kg (1000) + 50/kg/d
For each kg > 10
(40) + 2/kg/h
For each kg >10
>20 kg (1,500) + 20/kg/d
For each kg > 20
(60) + 1/kg/h
For each kg > 20
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Calculating Maintenance Fluids
The Holliday-Segar Formula
Case #1
An 32 kg girl is admitted for elective surgery
and is NPO. She has normal renal
function, no diarrhea and no fever. Whatwould her maintenance fluids be?
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Calculating Maintenance Fluids
The Holliday-Segar Formula
First 10 kg 100 ml/kg/day x 10 = 1000 ml
Second 10 kg 50 ml/kg/day x 10 = 500 ml
Last 12 kg 20 ml/kg/day x 12 = 240 ml
________________________________________
Total 32 kg 1740 ml/dayor
72.5 ml/hr
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Calculating Maintenance Fluids
The Holliday-Segar Formula
First 10 kg 4 ml/hr x 10 = 40 mlSecond 10 kg 2 ml/hr x 10 = 20 ml
Last 12 kg 1 ml/hr x 12 = 12 ml
___________________________________
Total 32 kg 72 ml/hr
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Maintenance Electrolytes
Electrolyte loss can all be considered
urinary
Sodium 3 mEq/100 ml
Potassium 2 mEq/100 ml
Chloride 2 mEq/100 ml
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We all need some Sugar…
Glucose is added to:
– Prevent ketosis
– Limit protein catabolism
20% of caloric need made up of glucose is
sufficient to prevent severe catabolism
– 5 grams glucose for every 100 cal
– D5W (5% dextrose water) is an appropriate
base for electrolyte solutions
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Putting it Together
Maintenance IVF will need: – Water
– Glucose
– Sodium – Potassium
– Chloride
Your choices:
– D5 0.2 NS with 20 mEq KCl/L (<18 month old) – D5 0.45 NS with 20 mEq KCl/L
(PEARL – Do not add KCl until after first void andpotassium level is known)
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Dehydration
Any combination of abnl intake and/or abnl
losses can lead to dehydration
– Most common cause in pediatrics is diarrhea
Types of dehydration:
– Isonatremic
– Hyponatremic
– Hypernatremic
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Taking the History
Vomiting
Diarrhea
Urine output (number of wet diapers)
Decreased po intake
Weight changes (acute)
Fever
Length of illness
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Degree of Dehydration
Clinical Signs Mild Moderate Severe↓ in body weight 3-5% 6-10% 11-15%
Fontenelle/Skin
turgor/Eyes
Normal (+/-) ↓ ↓↓
Skin Color Normal Pale Grey
Mucus
Membranes
Normal to Dry Dry Parched
Cap Refill 2-3 seconds 3-4 seconds > 4 seconds
Heart Rate Normal ↑ ↑↑
Blood Pressure Normal Postural changes Hypotension
Urine Output Normal to slight ↓ Oliguria Severe oliguria or
anuria
Tears ↓ ↓↓ to absent Absent
Urine Spec Grav >1.020 ↑↑ ↑↑↑ or anuria
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How dry are you?
Only with accurate weights can you beprecise – how often does that happen?
Level of dehydration can be estimated
using the H&P and labs
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A Case of Dehydration
A 10 kg infant has had severe diarrhea for
the past 2 days, decreased formula intake,
a sunken fontenelle, no tears and oliguria.
How dehydrated is this infant?
What laboratory values do you want toobtain?
How do you want to manage this infant?
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Management of Dehydration
Step 1 – Determine the presence anddegree of dehydration
Step 2 – Obtain appropriate laboratory
data (iso/hypo/hyper-natremia)Step 3 – Bolus 20 mL/kg of NS (isotonicand will stay in the intravascular space)
Step 4 – Determine patient’s needs fornext 24 to 48 hours
Maintenance + Deficit + On-going losses
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A Case of Dehydration
This infant is ~10% dehydrated given the
history and PE findings
Na 140, K 3.7, Cl 107, HCO3 22
Bolus 20 mL/kg NS improved urine
output
Still refusing po intake and still stooling ata rate of 20 mL/hr
Now what?
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A Case of Dehydration
PEARL 1000 mL (1L) = 1000 gm (1 kg)
Maintenance = 1000 mL (100 mL/kg/day)Deficit = 1000 mL (10% of a 10 kg infant)
1000 mL – 200 mL (bolus given) = 800 mL remains
to be given
On-going losses = 20 mL/hr 480 mL/day
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A Case of Dehydration
For isonatremic and hyponatremic
dehydration
Give HALF of Maintenance and Deficit in first 8
hours and remainder over the next 16 hours
(Maintenance + Deficit) – Bolus = 1800 mL
Therefore: Run 900 mL over 8 hours at 112 mL/hrThen, 900 mL over 16 hours at 56 mL/hr
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Hypernatremic Dehydration
Total body water losses in excess of
sodium losses
Hypernatremia must be corrected
SLOWLYHyperosmolality causes cells to shrink – especially
in the CNS
Correcting too quickly will cause fluid to be rapidlydrawn into brain cells
Cerebral edema is BAD
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Hypernatremic Dehydration
A Case
A 5 kg infant presents with a 5 day history ofviral syndrome with fever, vomiting and
diarrhea. Signs and symptoms reveal an
infant who is 10% dehydrated. Laboratory
data reveals a Na of 160.
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Hypernatremic Dehydration
Hypernatremic dehydration is corrected EVENLY
over 48 hours
Bolus 20 mL/kg to restore intravascular volume
Maintenance = 100 mL/kg x 5 kg = 500ml/day48 hours of maintenance = 1000 mL
Deficit = 0.5 kg = 500 mL500 mL – 100 mL (bolus given) = 400 mL remain to be given
Total fluids over a 48 hour period is 1400 mL or
29 mL/hr
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Oral Rehydration Therapy
Indications
– <10% dehydrated
– Following initial volume resuscitation
Contraindications
– >10% dehydrated/circulatory instability
– Severe vomiting
– Abdominal distention/ absent bowel sounds
– Severe hypo- or hyper- natremia
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Oral Rehydration Therapy
Examples – Pedialyte, Infalyte, WHO
rehydration solution
Administration
– 25 mL/kg/hr of deficit over the first 6 hours
– Then 10 mL/kg/hr over the next 6 hours (if
needed)
– When repleted then maintenance volumescan be given
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ANY QUESTIONS ??