Fluids and ElectrolytesFluids and Electrolytes

TUMS-III Lecture SeriesTUMS-III Lecture SeriesM. Kwan Chan-House, MDM. Kwan Chan-House, MD

ObjectivesObjectives

Learn to calculate maintenance fluidsLearn to calculate maintenance fluids

Learn maintenance electrolyte needsLearn maintenance electrolyte needs

Learn the signs and symptoms of Learn the signs and symptoms of dehydrationdehydration

Learn to calculate replacement fluids for Learn to calculate replacement fluids for isonatremic/hyponatremic/hypernatremic isonatremic/hyponatremic/hypernatremic dehydrationdehydration

Oral Rehydration TherapyOral Rehydration Therapy

““Just Start Maintenance”…Just Start Maintenance”…

Maintenance fluid provide the Maintenance fluid provide the water and water and electrolyteselectrolytes equal to those lost simply for equal to those lost simply for being alive and having a basal metabolic ratebeing alive and having a basal metabolic rate

Metabolism makes Metabolism makes heat and soluteheat and solute that you that you need to get rid of to maintain homeostasisneed to get rid of to maintain homeostasis– Insensible fluid loss – dissipates heat by evaporation Insensible fluid loss – dissipates heat by evaporation

of water from skin and URT (50% of maintenance of water from skin and URT (50% of maintenance needs)needs)

– Soluble waste is excreted in urine (50% of Soluble waste is excreted in urine (50% of maintenance needs)maintenance needs)

Some ConversionsSome Conversions

1 mL = 1 cc1 mL = 1 cc

30 cc = 1 ounce30 cc = 1 ounce

Calculating Maintenance FluidsCalculating Maintenance Fluids

The Holliday-Segar FormulaThe Holliday-Segar Formula(Burn these numbers into your mind)(Burn these numbers into your mind)

100-50-20100-50-20

4-2-14-2-1

Calculating Maintenance FluidsCalculating Maintenance Fluids

The Holliday-Segar FormulaThe Holliday-Segar FormulaBased on calorie expenditureBased on calorie expenditure

1 mL of water needed for each kcal used1 mL of water needed for each kcal used

Weight (kg)Weight (kg) kcal/d or mL/dkcal/d or mL/d kcal/h or mL/hkcal/h or mL/h

0 to 10 kg0 to 10 kg 100100/kg/d/kg/d 44/kg/h/kg/h

11 to 20 kg11 to 20 kg (1000) + (1000) + 5050/kg/d/kg/dFor each kg > 10For each kg > 10

(40) + (40) + 22/kg/h/kg/hFor each kg >10For each kg >10

>20 kg>20 kg (1,500) +(1,500) + 20 20/kg/d/kg/dFor each kg > 20For each kg > 20

(60) + (60) + 11/kg/h/kg/hFor each kg > 20For each kg > 20

Calculating Maintenance FluidsCalculating Maintenance Fluids

The Holliday-Segar FormulaThe Holliday-Segar FormulaCase #1Case #1

An 32 kg girl is admitted for elective surgery An 32 kg girl is admitted for elective surgery and is NPO. She has normal renal and is NPO. She has normal renal function, no diarrhea and no fever. What function, no diarrhea and no fever. What would her maintenance fluids be?would her maintenance fluids be?

Calculating Maintenance FluidsCalculating Maintenance Fluids

The Holliday-Segar FormulaThe Holliday-Segar Formula

First 10 kg First 10 kg 100100 ml/kg/day x 10 = 1000 ml ml/kg/day x 10 = 1000 mlSecond 10 kg Second 10 kg 5050 ml/kg/day x 10 = 500 ml ml/kg/day x 10 = 500 mlLast 12 kg Last 12 kg 2020 ml/kg/day x 12 = 240 ml ml/kg/day x 12 = 240 ml________________________________________________________________________________Total 32 kg 1740 ml/dayTotal 32 kg 1740 ml/day

oror 72.5 ml/hr72.5 ml/hr

Calculating Maintenance FluidsCalculating Maintenance Fluids

The Holliday-Segar FormulaThe Holliday-Segar Formula

First 10 kg First 10 kg 44 ml/hr x 10 = 40 ml ml/hr x 10 = 40 ml

Second 10 kg Second 10 kg 22 ml/hr x 10 = 20 ml ml/hr x 10 = 20 ml

Last 12 kg Last 12 kg 11 ml/hr x 12 = 12 ml ml/hr x 12 = 12 ml

______________________________________________________________________

Total 32 kg 72 ml/hrTotal 32 kg 72 ml/hr

Maintenance ElectrolytesMaintenance Electrolytes

Electrolyte loss can all be considered Electrolyte loss can all be considered urinaryurinary

SodiumSodium 3 mEq/100 ml3 mEq/100 ml

PotassiumPotassium 2 mEq/100 ml2 mEq/100 ml

ChlorideChloride 2 mEq/100 ml2 mEq/100 ml

We all need some Sugar…We all need some Sugar…

Glucose is added to:Glucose is added to:– Prevent ketosisPrevent ketosis– Limit protein catabolismLimit protein catabolism

20% of caloric need made up of glucose is 20% of caloric need made up of glucose is sufficient to prevent severe catabolismsufficient to prevent severe catabolism– 5 grams glucose for every 100 cal5 grams glucose for every 100 cal– D5W (5% dextrose water) is an appropriate D5W (5% dextrose water) is an appropriate

base for electrolyte solutionsbase for electrolyte solutions

Putting it TogetherPutting it Together

Maintenance IVF will need:Maintenance IVF will need:– WaterWater– GlucoseGlucose– SodiumSodium– PotassiumPotassium– ChlorideChloride

Your choices:Your choices:– D5 0.2 NS with 20 mEq KCl/L (<18 month old)D5 0.2 NS with 20 mEq KCl/L (<18 month old)– D5 0.45 NS with 20 mEq KCl/L D5 0.45 NS with 20 mEq KCl/L (PEARL – Do not add KCl until after first void and (PEARL – Do not add KCl until after first void and

potassium level is known)potassium level is known)

DehydrationDehydration

Any combination of abnl intake and/or abnl Any combination of abnl intake and/or abnl losses can lead to dehydrationlosses can lead to dehydration– Most common cause in pediatrics is diarrheaMost common cause in pediatrics is diarrhea

Types of dehydration:Types of dehydration:– IsonatremicIsonatremic– HyponatremicHyponatremic– HypernatremicHypernatremic

Taking the HistoryTaking the History

VomitingVomitingDiarrheaDiarrheaUrine output (number of wet diapers)Urine output (number of wet diapers)Decreased po intakeDecreased po intakeWeight changes (acute)Weight changes (acute)FeverFeverLength of illnessLength of illness

The Physical ExamThe Physical Exam

FeverFeverElevated HRElevated HROrthostatic changes (Orthostatic changes (↓10 mmHg Diastolic BP ↓10 mmHg Diastolic BP and/or ↑10 bpm from lying to standing)and/or ↑10 bpm from lying to standing)Sunken fotanelleSunken fotanelleSunken eyesSunken eyesLack of tearsLack of tearsDry lips/mucosal membranesDry lips/mucosal membranesPoor skin tugor (tenting)Poor skin tugor (tenting)Prolonged capillary refill time/Skin colorProlonged capillary refill time/Skin color

The LabsThe Labs

Lytes (Na, K, Cl, HCO3)Lytes (Na, K, Cl, HCO3)

BUN/Cr (ratio > 20)BUN/Cr (ratio > 20)

Urine specific gravityUrine specific gravity

Elevated hematocrit (hemoconcentration)Elevated hematocrit (hemoconcentration)

FeNaFeNa

Degree of DehydrationDegree of DehydrationClinical SignsClinical Signs MildMild Moderate Moderate SevereSevere

↓ ↓ in body weightin body weight 3-5%3-5% 6-10%6-10% 11-15%11-15%

Fontenelle/Skin Fontenelle/Skin turgor/Eyesturgor/Eyes

Normal (+/-)Normal (+/-) ↓↓ ↓↓↓↓

Skin ColorSkin Color NormalNormal PalePale GreyGrey

Mucus Mucus MembranesMembranes

Normal to DryNormal to Dry DryDry ParchedParched

Cap RefillCap Refill 2-3 seconds2-3 seconds 3-4 seconds3-4 seconds > 4 seconds> 4 seconds

Heart RateHeart Rate NormalNormal ↑↑ ↑↑↑↑

Blood PressureBlood Pressure NormalNormal Postural changesPostural changes HypotensionHypotension

Urine OutputUrine Output Normal to slight Normal to slight ↓↓ OliguriaOliguria Severe oliguria or Severe oliguria or anuriaanuria

TearsTears ↓↓ ↓↓ ↓↓ to absentto absent AbsentAbsent

Urine Spec GravUrine Spec Grav >1.020>1.020 ↑↑↑↑ ↑↑↑ ↑↑↑ or anuriaor anuria

How dry are you?How dry are you?

Only with accurate weights can you be Only with accurate weights can you be precise – how often does that happen?precise – how often does that happen?

Level of dehydration can be estimated Level of dehydration can be estimated using the H&P and labsusing the H&P and labs

A Case of DehydrationA Case of Dehydration

A 10 kg infant has had severe diarrhea for A 10 kg infant has had severe diarrhea for the past 2 days, decreased formula intake, the past 2 days, decreased formula intake, a sunken fontenelle, no tears and oliguria. a sunken fontenelle, no tears and oliguria.

How dehydrated is this infant?How dehydrated is this infant?

What laboratory values do you want to What laboratory values do you want to obtain?obtain?

How do you want to manage this infant?How do you want to manage this infant?

Management of DehydrationManagement of Dehydration

Step 1 – Determine the presence and Step 1 – Determine the presence and degree of dehydrationdegree of dehydrationStep 2 – Obtain appropriate laboratory Step 2 – Obtain appropriate laboratory data (iso/hypo/hyper-natremia)data (iso/hypo/hyper-natremia)Step 3 – Bolus 20 mL/kg of NS (isotonic Step 3 – Bolus 20 mL/kg of NS (isotonic and will stay in the intravascular space)and will stay in the intravascular space)Step 4 – Determine patient’s needs for Step 4 – Determine patient’s needs for next 24 to 48 hoursnext 24 to 48 hours

Maintenance + Deficit + On-going lossesMaintenance + Deficit + On-going losses

A Case of DehydrationA Case of Dehydration

This infant is ~10% dehydrated given the This infant is ~10% dehydrated given the history and PE findingshistory and PE findings

Na 140, K 3.7, Cl 107, HCO3 22Na 140, K 3.7, Cl 107, HCO3 22

Bolus 20 mL/kg NS Bolus 20 mL/kg NS improved urine improved urine outputoutput

Still refusing po intake and still stooling at Still refusing po intake and still stooling at a rate of 20 mL/hra rate of 20 mL/hr

Now what?Now what?

A Case of DehydrationA Case of Dehydration

PEARL PEARL 1000 mL (1L) = 1000 gm (1 kg) 1000 mL (1L) = 1000 gm (1 kg)

Maintenance = 1000 mL (100 mL/kg/day)Maintenance = 1000 mL (100 mL/kg/day)

Deficit = 1000 mL (10% of a 10 kg infant)Deficit = 1000 mL (10% of a 10 kg infant)1000 mL – 200 mL (bolus given) = 800 mL remains 1000 mL – 200 mL (bolus given) = 800 mL remains to be givento be given

On-going losses = 20 mL/hr On-going losses = 20 mL/hr 480 mL/day 480 mL/day

A Case of DehydrationA Case of Dehydration

For For isonatremic and hyponatremic isonatremic and hyponatremic dehydrationdehydration

Give HALF of Maintenance and Deficit in first 8 Give HALF of Maintenance and Deficit in first 8 hours and remainder over the next 16 hourshours and remainder over the next 16 hours

(Maintenance + Deficit) – Bolus = (Maintenance + Deficit) – Bolus = 1800 mL1800 mL

Therefore: Run 900 mL over 8 hours at 112 mL/hrTherefore: Run 900 mL over 8 hours at 112 mL/hr

Then, 900 mL over 16 hours at 56 mL/hrThen, 900 mL over 16 hours at 56 mL/hr

Hypernatremic DehydrationHypernatremic Dehydration

Total body water losses in excess of Total body water losses in excess of sodium lossessodium losses

Hypernatremia must be corrected Hypernatremia must be corrected SLOWLYSLOWLY

Hyperosmolality causes cells to shrink – especially Hyperosmolality causes cells to shrink – especially in the CNSin the CNS

Correcting too quickly will cause fluid to be rapidly Correcting too quickly will cause fluid to be rapidly drawn into brain cellsdrawn into brain cells

Cerebral edema is BADCerebral edema is BAD

Hypernatremic DehydrationHypernatremic Dehydration

A CaseA Case

A 5 kg infant presents with a 5 day history of A 5 kg infant presents with a 5 day history of viral syndrome with fever, vomiting and viral syndrome with fever, vomiting and

diarrhea. Signs and symptoms reveal an diarrhea. Signs and symptoms reveal an infant who is 10% dehydrated. Laboratory infant who is 10% dehydrated. Laboratory

data reveals a Na of 160.data reveals a Na of 160.

Hypernatremic DehydrationHypernatremic Dehydration

Hypernatremic dehydration is corrected EVENLY Hypernatremic dehydration is corrected EVENLY over 48 hours over 48 hours

Bolus 20 mL/kg to restore intravascular volumeBolus 20 mL/kg to restore intravascular volume

Maintenance = 100 mL/kg x 5 kg = 500ml/day Maintenance = 100 mL/kg x 5 kg = 500ml/day 48 hours of maintenance = 1000 mL48 hours of maintenance = 1000 mL

Deficit = 0.5 kg = 500 mLDeficit = 0.5 kg = 500 mL500 mL – 100 mL (bolus given) = 400 mL remain to be given500 mL – 100 mL (bolus given) = 400 mL remain to be given

Total fluids over a 48 hour period is 1400 mL or Total fluids over a 48 hour period is 1400 mL or

29 mL/hr29 mL/hr

Oral Rehydration TherapyOral Rehydration Therapy

Indications Indications – <10% dehydrated<10% dehydrated– Following initial volume resuscitationFollowing initial volume resuscitation

ContraindicationsContraindications– >10% dehydrated/circulatory instability>10% dehydrated/circulatory instability– Severe vomitingSevere vomiting– Abdominal distention/ absent bowel soundsAbdominal distention/ absent bowel sounds– Severe hypo- or hyper- natremiaSevere hypo- or hyper- natremia

Oral Rehydration TherapyOral Rehydration Therapy

Examples – Pedialyte, Infalyte, WHO Examples – Pedialyte, Infalyte, WHO rehydration solutionrehydration solution

AdministrationAdministration– 25 mL/kg/hr of deficit over the first 6 hours25 mL/kg/hr of deficit over the first 6 hours– Then 10 mL/kg/hr over the next 6 hours (if Then 10 mL/kg/hr over the next 6 hours (if

needed)needed)– When repleted then maintenance volumes When repleted then maintenance volumes

can be givencan be given

ANY QUESTIONS ??ANY QUESTIONS ??