IV Fluids

last authored: March 2011, David LaPierre
last reviewed:

 

 

Introduction

Intravenous (IV) fluids are a key treatment for dehydration and hemodynamic instability. They can be used for resuscitation or for maintenance. An IV has a number of parameters:

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Types of Fluids

There are many options when choosing IV fluids.

 

glucose (g/L)

Na+ (mEq/L)

K+ (mEq/L)

Cl- (mEQ/L)

lactate (mEq/L)

comments

normal saline (0.9%)

0

154

0

154

0

maintenance, resuscitation

half-normal saline (0.45%)

0

77

0

77

0

maintenance

ringer's lactate

0

130

4

109

28

3 MEq/L Ca2+ as well

 

D5W

50

0

0

0

0

maintenance

D5W + 1/2%NS

50

77

 

77

   

2/3 + 1/3

           

normal plasma

           

 

Choosing IV fluids

Normal saline is the easiest to remember in terms of components. It can be used for resuscitation or for maintenance.

 

Potassium chloride (KCl) should be added to IV fluids if the patient is receiving nothing by mouth and has normal renal function, as the kidneys are constantly filtering potassium. It should be used with caution if renal function is impaired.

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Adult Fluid Needs

 

Recuscitation

An adult bolus is normally 500-1000ml of nromal saline or ringer's lactate. Repeat as needed until stabilized; consider colloid after 2 boluses. If using colloids, one needs 3x the amount to restore fluid volume. In a recuscitation situation, if a few litres don't work, give blood, even uncrossmatched blood. The length of time spend in shock is important for survival.

 

 

Maintenance

Daily fluid needs for an adult are 2500-3000 ml, plus electrolytes.

Weight loss or weight gain are the best measure of fluid balance.

 

increased needs

fever (12% per rise in degree celsius)

tachypnea

vomiting and diarrhea

high output renal failure

decreased needs

congested heart failure

mechanical ventilation

oligouric renal failure

If intake is limited to IV for more than a week, total parenteral nutrition should be instituted.

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Pediatric Fluid Needs

 

80 cc/kg of children is blood

 

Recuscitation

A pediatric fluid bolus is 10-20 ml/kg. Regarding fluid types, NS or 1/2 NS are usually used in children, while in neonates, 1/4 - 1/2 NS are often used.

 

 

Maintenance

The 4-2-1 rule

  • 4 cc's/kg/hr for first ten kg
  • 2 cc's/kg/hr for next ten kg
  • 1 cc/kg/hr for each kg thereafter

ie a 25 kg child will require 65 cc's/hr.

Holliday Segar formula

  • first 10 kg: 100 ml/kg/day
  • second 10 kg: 50 ml/kg/day
  • every additional kg: 20 ml/kg/day

 

These amounts needs to be increased in situations of increased loss, ie fever or with burns.

 

Neonates have higher fluid requirements: ~150 ml/kg/day.

 

For caloric intake, D5W is used for most children and D10W - for neonates (less than 1 month).

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Hanging IV Fluids

Macrodrip is the most common, delivering 1ml every 15 drops. Microdrip, used in precise situations, offers 1ml/60 drops.

Infusion rate is commonly calculated per hour. For example a rate of 125ml/hr would equal a 1000ml bag/8 hours.

After hourly flow rate has been calculated, determine minute flow rate (ie 125 ml/hr =

flow rate/hr / 60 = flow rate/min

 

Ensure the patient is aware of proper site placement, and is not experiencing signs or symptoms of phlebitis or interstitial extravasation.

 

 

 

Clinical Usage and Tips

Measure adequacy with urine output, aiming for 1-2 mg/kg/hr

 

Monitor for signs of dehydration and fluid overload:

dehyration

  • tachycardia, dropped blood pressure
  • no tears
  • decreased urine output
  • dry mouth, tongue, skin
  • decreased skin turgor
  • sunken fontanelles

overload

  • shortness of breath
  • fluid crackles in the lungs
  • ankle or sacral edema
  • increased jugular venous pressure

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Resources and References

 

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