Dr Mere Kende

MBBS, Mmed (Path), MACTM, MAACB, MACRRM

Lecturer- SMHS

Fluid Balance& IV Fluids

Outline

Normal Body Fluid Physiology Types and composition of Parenteral Fluids Indications for IV Fluids Specific replacement Fluids Calculating Minimal fluid requirement Complications of IV Fluids Burn Fluid Management IV Fluids in Shock Treatment Examples of calculating IVF requirement

Principles of Fluids and Electrolytes

Fluid Compartments

Example: 70-kg male

Total Body Water: 42,000 mL (60% of BW)

• Intracellular: 28,000 mL (40% of BW)

• Extracellular: 14,000 mL (20% of BW)

• Plasma: 3500 mL (5% of BW)

• Interstitial: 10,500 mL (15% of BW)

Composition of Body Fluids

Fluid distribution

Total

Body

water

(ml/kg)

IC Fluids

(ml/kg)

EC Fluids

(ml/kg)

Blood

Volume

(ml/kg)

Neonate 800

(80%BW) 350 450 96

Infant 700 400 300 80

Child 650 400 250 70

Adult 600 (60% BW)

400 200 60

Total Blood Volume (TBV)

TBV = 5600 mL (5-8% of BW)

Red Blood Cell Mass

Male, 20–36 mL/kg (1.15–1.21 L/m2);

female, 19–31 mL/kg (0.95–1.0 L/m2

Water Balance

• 70-kg male

The minimum obligate water requirement

to maintain homeostasis (assuming normal

temperature and renal concentrating ability

and minimal solute [urea, salt] excretion) is

about 800 mL/d, which would yield 500

mL of urine/day.

“Normal” Intake: 2500 mL/d (about 35

mL/kg/d baseline)

Oral liquids: 1500 mL

Oral solids: 700 mL

Metabolic (endogenous): 300 mL

“Normal” Output: 1400–2300 mL/d

1. Urine: 800–1500 mL

2. 2. Stool: 250 mL

3. Insensible loss: 600–900 mL (lungs and

skin).

(With fever, each degree above 37°C adds

2.5 mL/kg/d to insensible loss; insensible

losses are decreased if a patient is on a

ventilator; free water gain may occur from

humidified ventilation.)

Electrolyte Requirements

70-kg adult, unless otherwise specified

Sodium (as NaCl): 80–120 mmol/d

And Pediatric patients, 3–4 mmol/kg/ 24 h

Chloride: 80–120 mEq (mmol)/d, as NaCl

Potassium: 50–100 mmol/d) (Pediatric

patients, 2–3 mmol/kg/24 h ).

Note: 1gram KCl- has 13mmol/L potassium’

In the absence of hypokalemia and with normal

renal function, most of this is excreted in the

urine. Of the total amount of potassium, 98% is

intracellular, and 2% is extracellular.

Thus, assuming the serum potassium level is normal, about 4.5 mmol/L (mEq/L), the total extracellular pool of K+ = 4.5 × 14 L = 63mmol.

Potassium is easily interchanged between intracellular and extracellular stores under conditions such as acidosis. Potassium demands increase with diuresis and building of new body tissues (anabolic states).

Calcium: 1–3 gm/d,

Most of which is secreted by the GI tract. Routine

administration is not needed in the absence of

specific indications.

Magnesium: 20 mEq/d (mmol/d).

Routine administration is not needed in the absence of

specific indications, such as parenteral

hyperalimentation, massive diuresis, ethanol

abuse (frequently needed) or preeclampsia.

Glucose Requirements

100–200 g/d (65–75 g/d/m2). i.e., 2-4litres of 5% dextrose solution

During starvation, caloric needs are supplied by body fat and protein; the majority of protein comes from the skeletal muscles. Every gram of nitrogen in the urine represents 6.25 g of protein broken down.

The protein-sparing effect is one of the goals of basic IV therapy. The administration of at least 100 g of glucose/d reduces protein loss by more than one-half. Virtually all IV fluid solutions supply glucose as dextrose (pure dextrorotatory glucose).

Pediatric patients require about 100–200 mg/kg/h.

COMPOSITION OF PARENTERAL FLUIDS

Parenteral fluids are generally classified based on Molecular Weight (MW) and Oncotic Pressure.

Colloids (MW >8000)- High Oncotic pressure (albumin)

crystalloids (MW <8000) - Low Oncotic Pressure (Dextrose)

Crystalloids

Colloids

• Albumin

• Blood products (RBCs, single-donor plasma, etc)

• Plasma protein fraction (Plasmanate)

.Synthetic colloids (hetastarch [Hespan], dextran)

Hartmann’s +/-5% glucose

Na+ 130mmol/L

Cl- 110 mml/L

K+ 5 mmol/L

Lactate 30 mmol/L

Ca++ 2 mmol/L

Baseline Fluid Requirement

Afebrile 70-kg Adult: 35 mL/kg/24 h

If not a 70-kg Adult:

Calculate the water requirement according to the

following “kg method”.

“kg method”

• For the 1st 10 kg of body weight: 100

mL/kg/d plus

• For the 2nd 10 kg of body weight: 50

mL/kg/d plus

• For the weight above 20 kg: 20 mL/kg/d

What is the minimum requirement?

70kg Man: D51/4NS with 20mmol/L KCl at 125ml/hr

(3L free water/day)

Adult Patients:

Use D51/4NS

Determine water requirement ‘kg method’

Divide by 24hr to determine the hourly rate

Paediatric patients:

Use the same solution as adults

“Kg method” vs”‘Meter square method”

Meter Squared method

Maintenance Fluid –

Calculate:1500/m2/day

Divide by 24hr to get the flow rate per hour

To calculate SA, use the ‘rules of sixes’

normogram

‘Rules of Sixes’ Normogram for Calculating Fluids

in Children

Weight- Pound-lbs (kg) Body Surface Area (m2) 3 (1.4) 0.1 6 (2.7) 0.2 12 (5.4) 0.3 18 (8.2) 0.4 24 (10.9) 0.5 30 (13.6) 0.6 36 (16.3) 0.7 42 (19.5) 0.8 48 (21.8) 0.9 60 (27.2) 1.0

After 60 lb, add 0.1 for each additional 10lb After 100 lb (45kg) treat as adult

Formal Body Surface Area Chart

2kg

40cm

0.14

Indications for IV Fluids

Indications: KVO

IV antibiotics/medications

Too sick/not eating well

Awaiting OT

Blood Transfusion

Blood Loss/Dehydration

Medical procedures

Cautions:

Children Brain injury

Elderly Alcohol Intoxication

Pneumonia Lung Infection

Renal Failure Heart failure

Diabetic ketoacidosis Electrolyte Disorders

What fluid to Use? General Principles

Avoid IV Fluids unless necessary

Consider benefits & Risks

Insert large Bore Needle (size 14-18) for urgent resuscitation

Choose a Proximal large veins

Avoid lower limbs if possible (risk of DVT/thrombophebitis)

General principles of IV Fluids

Minimal two attempts/failures in IV insertion -allow another colleague to try

Take as much time to search for ‘good vein

Intraosseus/CV line infusion or cut-down may be required (slide)

Adequately secure IV line

Consider risk of infection

IV line should ideally be dated, changed every 3 days

Intraosseous sites

Specific Replacement Fluids

Maintenance Fluid- Dextrose saline solution (eg D5 ½

NS)

Antibiotic Infusion ? Dextrose/saline

Issue of incompatibility

Presence of electrolyte disorders

Heart Failure

Renal Failure

Hypertension

Pyeloric stenosis- Normal Saline

Renal calculi –1/2, 1/3 strength NS or Dextrose solution

Hypokalemia – N/Saline with 20-40mmol KCL/hr

Hyponatremia- 0.9% N/S, avoid dextrose/low strength

N/S (higher % N/S if necessary)

Heat Stroke – Normal Saline

Burn Patient- Normal Saline (+/-colloids/Blood)

GIT Loss- Normal Saline +/KCl

Gastric Loss (NGT, emesis)- D5 ½ NS with 20mmol/L KCL

Diarrhoea: D5LR (hartmans) with 15mmol/L KCl. Use BW as

replacement guide (about 1L for each kg)

Bile loss: D5LR (Hartman’s) with 25mmol/L (1/2 amp) NaHCO3-

ml for ml

Pancreatic loss: D5LR with 50mmol/L (1amp) NaHCO3- ml for

ml

Diabetic Ketoacidosis-

start with N/saline and insulin infusion/ sliding scale, switch to

dextrose when glucose is <15mmol/L,

continue dextrose insulin until acidosis and dehydration

corrected,

K+ may be required later

Haemorrhage Shock –

1st choice Hartman’s/Ringer’s Lactate (warmed)

2nd Choice N/S (risk of hyperchloraemic acidosis with impaired

RF)

Colloid with caution (Burn patients)

Blood Transfusion if in shock >30-40% blood loss

Resuscitation/Shock----(except cardiogenic)

Use crystalloid -Normal Saline/Hartmans preferred

Amount replaced – approx 3mls blood lost requires 1ml crystalloid

Blood transfusion may be required if hemorrhaging/anaemic or not responding to crystalloids or more than allowable blood loss (>30%)

Aim –BP systolic >100mmHg, HR <120/min, Urine Output >0.5ml/kg/hr

Estimated Fluid and Blood Losses based on

Patient’s (70kg) Initial Presentation (ATLS)

Blood Loss CLASS I Class II Class III Class IV

Blood Loss (ml) Up to 750 750-1500 1500-2000 >2000

% Blood Loss Up to

15%

15-30% 30-40% >40%

PR

BP <100 >100 >120 >140

Pulse Pressure

(mmHg)

normal normal decreased decreased

RR 14-20 20-30 30-40 >35

Urine Output

(ml/hr)

>30 20-30 5-15 Negligible

CNS/mental Status Slight

anxious

Mildly anxious Anxious,

confused

Confused, lethargic

Fluid Replacement

(3:1)

crystalloid crystalloid Crystalloid

& Blood

Crystalloid & Blood

IVF in Burn Patient ABC

Assess % Burn

IVF resuscitation

Prevent On-going Loss

Monitor Complications

Prevent Infection

Prevent Contractures

Burn Patients:

Use the Parkland or

Rule of Nines Formula

Parkland Formula

Calculate Total Fluid requirement during

first 24hr:

=% Body burn x BW (kg) x 4ml

Parkland formula

Total fluid requirement in 24 hours =

4 ml×(total burn surface area (%))×(body weight (kg))

Replace over 24hrs

½ over 1st 8hr (from time of burn)

¼ over 2nd 8hr

¼ over 3rd 8hr

Children receive maintenance fluid in addition, at hourly

rate of;

4 ml/kg for first 10 kg of body weight plus

2 ml/kg for second 10 kg of body weight plus

1 ml/kg for > 20 kg of body weight

“Rules of Nine’

Used to estimate % body burn in adults

Estimation of Fluid loss (ml)= 25 x % Body burn x m2 BSA

This system is used to estimate ongoing fluid losses from a burn until it is healed or grafted

How to Assess % Burn?-3 Methods

Method1. Palmar surface—

The surface area of a patient’s palm (including fingers) is roughly

1% of total body surface area.

Palm surface are can be used to estimate relatively small

burns ( < 15% of total surface area) or very large burns ( >

85%, when unburnt skin is counted).

For medium sized burns, it is inaccurate.

Method 2. Wallace rule of nines—

This is a good, quick way of estimating medium to large burns in

adults.

The body is divided into areas of 9%, and the total burn area

can be calculated.

In adults, this is reasonable method. It is not accurate in

children.

Method 3. Lund and Browder chart—

This chart, if used correctly, is the most accurate method.

It compensates for the variation in body shape with age and

therefore can give an accurate assessment of burns area in

children.

Aim For Normal Urine Output

Adult: 0.5ml/kg/hr

Children 1ml/kg/hr

Infants <1yr 2ml/kg/hr

Shock Definition/causes of shock

Clinical Features

Management

Urgent Treatment (ABC)

Immediate management

Long term management

Effects of Loss of Fluid?

Decreased cardiac Output (low BP, high PR)

Poor tissue perfusion and oxygenation

HYPOXIA (acidosis)

Impaired Renal perfusion (impaired electrolytes/acidosis)

Anaerobic Metabolism -Lactic Acidosis

Lack of ATP generation

Damage to cell membranes

Swelling and damage to cells and death

SIGNS OF DEHYDRATION-children

MOST RELIABLE IS LOSS OF BODY WEIGHT

OTHERS

PALLOR/POOR CAPILLARY REFILL

DEEP BREATHING

DECREASE SKIN TURGOR

INCREASE D THRIST

OTHER SIGNS OILGURIA, RESTLESSNESS, LETHARGY, SUNKEN EYES,

DRY MOUTH, SUNKEN FONTENALLE, ABSENCE OF TEARS—POOR SENSITIVITY FOR MILD MODERATE DEHYDRATION

For children,

<4% BW loss -------no clinical signs

4-6% BW loss -----clinical signs present

>7% BW loss-------acidosis and acidosis present

IVF Treatment

Bolus:

1-2 litres in adults &

20ml/kg bolus in Children

Assess for Response to initial Resuscitation

Rapid Response Transient

Response

No Response

Vital Signs Return to Normal Transient

improvement,

recurrence of inc HR

& Low BP

Remain abnormal

Estimated Blood

Loss

Minimal 10-20% Moderate & On-

going (20-40%)

Severe >40%

Need for More

crystalloids

Low High high

Need for blood Low Moderate to high Immediate

Blood Preparation Type & Cross Match Type-Specific Emergency blood

Release

Need for operative

intervention

probably Likely Highly likely

Early presence of

surgeon

Yes Yes Yes

How to Assess Adequate Fluid

Response

BP & PR- not very sensitive

CVP & Skin colour-difficult to assess

Volume of Urine Output-sensitive and

prime indicator

Complications of IV Fluids

Pulmonary Oedema

Heart Failure

Increased Intracranial Pressure

Electrolyte Imbalance

Worked examples of burns

resuscitation

A 25 year old man weighing 70 kg with a 30% flame burn was admitted to PMGH ED at 4 pm. His burn occurred at 3 pm. Picked up by ambulance, given IL N/S on transit plus morphine & oxygen

1) Total fluid requirement for first 24 hours. (parkland Formula)

4 ml×(30% total burn surface area)×(70 kg) = 8400 ml in 24 hours

2) Half to be given in first 8 hours, half over the next 16 hours. Will receive (4200 ml) during 0-8 hours and 4200 ml during 8-24 hours

3) Subtract any fluid already received from amount required for first

8 hours.

Has already received 1000 ml from emergency services, and

so needs further 3200 ml in first 8 hours after injury

4) Calculate hourly infusion rate for first 8 hours.

Divide amount of fluid calculated in (3) by time left until it

is 8 hours after burn

Burn occurred at 3 pm, so 8 hour point is 11 pm.

It is now 4 pm, so need 3200 ml over next 7 hours: 3200/7 = 457 ml/hour from 4 pm to 11 pm

5) Calculate hourly infusion rate for next 16 hours

Divide figure in (2) by 16 to give fluid infusion rate Needs 4200 ml over 16 hours: 4200/16 = 262.5 ml/hour from 11 pm to 3 pm next day

How to calculate Maintenance fluid in a

child?

A 24 kg child with a resuscitation burn will need the following maintenance fluid:

4 ml/kg/hour for first 10 kg of weight =

40 ml/hour plus

2 ml/kg/hour for next 10 kg of weight =

20 ml/hour plus

1 ml/kg/hour for next 4 kg of weight =

1×4 kg = 4 ml/hour

Total = 64 ml/hour

References

Advanced Trauma Life Support For Doctors (ATLS) 7th

Edition 2005

L. Gomella, Clinician’s Pocket References , 2007

Primary Care Manual RFDS--Queensland - 2007