Maintenance fluid

Fluid Therapy

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FLUID THERAPY

RESUSCITATION MAINTENANCE

Crystalloid Colloid ELECTROLYTES NUTRITION

1. Replace acute loss 1. Replace normal loss
(hemorrhage, GI loss, (IWL + urine+ faecal)
3rd space etc) 2. Nutrition support


Volume of Distribution of Water

Solids
///////////////////// 60%-Males
H2O 50%-Females


Solids 40% of Wt

Intracellular Extracellular
(2/3) (1/3)
H2O H2O

Na


E.C.F. COMPARTMENTS

Interstitial 3/4 Intra-
vascular
1/4
H2O H2O

Na Na
Colloids
& RBC


“Third Space”
• Acute sequestration in a body compartment
that is not in equilibrium with ECF
• Examples:
– Intestinal obstruction
– Severe pancreatitis
– Peritonitis
– Major venous obstruction
– Capillary leak syndrome
– Burns


Daily Fluid Balance
Intake:
1-1.5L

Insensible Loss
-Lungs 0.3L
-Sweat 0.1 L

Urine: 1.0 to 1.5L


Body Water and Fluid
Compartments
TBW = 0.6 or 0.5 x kg
TBW = ECF + ICF
(1/3) (2/3)
ECF = extracellular, ICF = intracellular
ECF = Interstitial + Plasma
(3/4) (1/4)
Fluid spaces are iso-osmolar due to water
movement


70 kg male

Total body water=60% body wt
=0.6X70=42 liters

ECF=1/3 ICF=2/3
0.3X42=13 liters 0.6 X42=25 liters

Blood=1/4 (ECF)
0.25X13=3. 3 liters


• Monitoring Fluid Therapy

• Serial exams: vascular fullness, skin turgor,
auscultation,, pulse quality, HR, RR
• Urine: specific gravity, volume
• Blood pressure
• Body weight
• Labs: electrolytes, BUN, Creatinine, lactate
(tissue perfusion)
• CVP


Why give fluids?
• Replace intravascular volume
• Improve tissue perfusion
• Replace fluid deficits (dehydration)
• Meet maintenance in NPO patient
• Replace ongoing losses (burns, etc.)
• Fluid diuresis to eliminate toxins
• Anesthetic and surgical support
• Replacement of specific components (blood,
plasma)
• Nutritional support (TPN, PPN)


Clinical Diagnosis

• Intravascular depletion
MAP= CO x SVR
Hemodynamic effects
• BP HR JVP
• Cool extremities
• Reduced sweating
• Dry mucus membranes

• E.C.F. depletion
– Skin turgor, sunken eyeballs
•Water Depletion – Weight
– Hemodynamic effects
Thirst
Hypernatremia

Electrolyte composition
mEq/L ICF ECF
Plasma Interstitial
Na+ 15 142
142 144
144
K+ 150
150 4 4
Ca2+ 2 5 2.5
Mg2+ 27 3 1.5

- 1 103 114
Cl
HCO3- 10 27 30
HPO42- 100 2 2
SO42- 20 1 1
Organic acid - 5 5
Protein 63 16 6


. Ion Distribution

COMPARTMENT CATION ANION Suitable solution

ICF K+ Mg++ HPO4-, Prot containing K+ Mg+
and HPO4-
ECF PLASMA Na+ Cl-, HCO3- Prot. High Na+ and Cl-

ISF Na+ Cl- HCO3-


Volume Deficit-Clinical Types

• Total body water:
– Water loss (diabetes insipidus, osmotic diarrhea)

• Extracellular:
– Salt and water loss (secretory diarrhea, ascites, edema)
– Third spacing

• Intravascular:
– Acute hemorrhage


Deficit
.
Dehydration Hypovolemia

* thirst • headache
* urine output  • nausea
• syncope

hypotonic isotonic
electrolytes electrolytes

5% Dextrose Ringer’s acetate
Ringer’s lactate
Normal saline


The IV Fluid Supermarket

• Crystalloids • Colloids
– Dextrose in water
– Albumin
• D5W
• 5% in NS
• D10W
• D50W • 20% (Salt Poor)
– Saline – Dextrans
• Isotonic (0.9% or “normal”) – Hetastarch
• Hypotonic (0.45%, 0.25%)
• Hypertonic
• Blood
– Combo
• D51/2NS
• D5NS
• D10NS
– Ringer’s lactate “physiologic”.
(K, HCO3, Mg, Ca)


COMPOSITION OF
PARENTERAL FLUIDS

• Parenteral fluids are generally classified
based on molecular weight and oncotic
pressure.
• Colloids have a molecular weight of
>8000 and have high oncotic pressure.
• Crystalloids have a molecular weight of
<8000 and have low oncotic pressure.


Nacl 5%
Na 850 mmol/L

CL 850 mmol/L

1700 mosm/L


Kcl 15%

K 2000mmol/L

Cl 2000mmol/L

2000 mosm/L


NaHco3 7.5%
Na 1000mmol/L
Hco3 1000mmol/L
2000mos/L

NaHco3 HCL H2co3 Nacl

H2co3 co2 H20


Dextrose Hyper Tonic
D25% 1180 mos/L

D50% 2770 mos/L


Colloids

• Dextran solutions (dextran 40 and dextran
70): Similar osmotic pressure to plasma. Dextrans
interfere with normal coagulation partly by
hemodilution of clotting factors and partly by
“coating” platelets and the vascular endothelium.
May promote renal failure.
• 20% Human serum albumin: Protein based
solution, falling out of favor in some circles secondary
to reports of increased mortality in the critically ill
adult population, and some debate still lays in its use
outside of the neonatal arena.


Colloids
• Colloid refers to a liquid that exerts osmotic
pressure due to large MW (greater than
30,000) particles in solution. A variety of
colloid solutions are seen for in hospital use:
• Hydroxyethyl starch (Hespan): hetastarch can
cause a coagulopathy, through hemodilution of
clotting factors, inhibition of platelet function and
reduction of the activity of factor VIII
• Pentastarch (Pentaspan):Pentastarch differs from
hetastarch in that it has a lower mean MW.
Preliminary studies also suggest that pentastarch
may have fewer adverse effects on coagulation than
hetastarch.25. No clear pediatric value yet.


Fluids can be described as being
.
from three categories
Isotonic - Fluid has the same osmolarity as plasma
Normal Saline (N/S or 0.9% NaCl),
Ringers Acetate(RA), Ringer’s lactate (RL)

Hypotonic -Fluid has fewer solutes than plasma
Water, 1/2 N/S (0.45% NaCl), and D5W
(5% dextrose in water) after the sugar is
used up

Hypertonic-Fluid has more solutes than plasma
7.5% Hco3Na/ 15% kcl
3% saline solution, 5%salin solution


Isotonic Dehydration
Most Common form of Dehydration

Occurs when fluids and electrolytes are lost in
even amounts

There are no intercellular fluid shifts in
isotonic dehydration

Common Causes
diuretic therapy
excessive vomiting
excessive urine loss
hemorrhage
decreased fluid intake


Hypertonic Dehydration
Second most common type of dehydration.

Occurs when water loss from ECF is greater than
solute loss

hyperventilation, pure water loss with high fevers,
and watery diarrhea.

Diabetic Ketoacidosis and Diabetes Insipidus

Iatrogenic Causes
prolonged NPO, excessive hypertonic fluids, sodium
bicarbonate,


Hypotonic Dehydration
Relatively Uncommon - Loss of more solute
(usually sodium) than water.

Hypotonic Dehydration causes fluid to shift from the
blood stream into the cells, leading to decreased
vascular volume and eventual shock
Seen in Heat Exhaustion

Increased cellular swelling -causes increased
intracrainial pressure - Confusion.
Seen in Heat Stroke


Isotonic infusion
• Ringer’s acetate
• Ringer’s lactate
• Normal saline

Replace acute/
increases ECF abnormal
loss

ICF ISF Plasma

700 ml 300 ml


Hypotonic infusion
• 5% dextrose

Replace Normal
increases ICF > ECF loss (IWL + urine)

ICF ISF Plasma

660 ml 270 ml 70 ml


Fluid Therapy

• Replacement
• Maintenance
• Repair deficit


BACIC PRINCIPLES

Replace Abnormal loss: GIT, 3rd space,
Ongoing loss, septic and
Hypovolemic shock

Maintain IWL + urine

Repair Acid base, electrolyte imbalances


FLUID SELECTION
• Replace : RA, RL, NS

• Maintain: N/2 + D (adult)

• Repair : NaHCO3 8,4%
KCl 15%
NaCl 3%


Maintenance
• IWL + urine
• Adults/children : 4:2:1
eg 60 kg 4 x 10 + 2 x 10 + 1 x 40 =
100ml/hr


Requirements
• Fever
• Restless/delirium
• Warm ambient temperature
• Hyperventilation


Requirements
• Hypothermia
• High humidity
• Oliguria/anuria
• Reduced consciousness
• Retention/oedema
• Increased intracranial pressure


Rationale of maintenance
solutions
• Fluid redistribution
• Basal requirement of potassium &
sodium
• electrolyte concentration in
infusion solutions


Electrolyte solutions

Plasma Isotonic Hypotonic solutions
solutions

290 308 273 278 290

278

Normal Ringer’s D5 KAEN 3B*
saline acetate/ lactate

* KAEN 3B : contains 50 mmol Na+, 20 mmol K+, 50 mmol
Cl-, 20 mmol lactate, 27 g dextrose per L.


Electrolyte Requirements:
70-kg adult
• Sodium (as NaCl): 80-150 mEq (mmol)/d
(Pediatric patients, 3-4 mEq/kg/ 24 h
[mmol/kg/24 h])
• Chloride: 80-150 mEq (mmol)/d, as NaCl
• Potassium: 50-100 mEq/d (mmol/d)
(Pediatric patients, 2-3 mEq/kg/24 h
[mmol/kg/24 h]).
• Calcium: 1-3 gr/d,
• Magnesium: 20 mEq/d (mmol/d).


Sodium Physiology

1. Sodium and its anions make up about 90% of
the total extracellular osmotically active
solute.
2. Serum osmolality (mOsm/kg H20) = 2 X
[Na+] + [glucose]/18 + [BUN]/2.8
3. For practical purposes, twice the Na+
concentration equals serum osmolality
because urea and glucose ordinarily are
responsible for less than 5% of the osmotic
pressure.


Hyponatremia
(Na+ <136 mEq/L
[mmol/L])
• Low osmolality. Further classified based on clinical assessment of
extracellular volume status
• Isovolemic.
No evidence of edema, normal BP. Caused by water intoxication
(urinary osmolality <80 mOsm), SIADH, hypothyroidism,
hypoadrenalism, thiazide diuretics, beer potomania
• Hypovolemic.
Evidence of decreased skin turgor and an increase in heart rate and
decrease in BP after going from lying to standing. Due to renal loss
(urinary sodium >20 mEq/L) from diuretics, postobstructive diuresis,
mineralocorticoid deficiency (Addison disease, hypoaldosteronism) or
extrarenal losses (urinary sodium <10mEq/L) from sweating, vomiting,
diarrhea, third spacing fluids (burns, pancreatitis, peritonitis, bowel
obstruction, muscle trauma)
• Hypervolemic.
Evidence of edema. urinary sodium <10 mEq/L). Seen with CHF,
nephrosis, renal failure, and liver disease


Symptoms: Usually with Na+
<125 mEq/L (mmol/L)
• severity of symptoms correlates with
the rate of decrease in Na+.
• ?Lethargy, confusion, coma
• ?Muscle twitches and irritability,
seizures
• ?Nausea, vomiting
• Signs:
Hyporeflexia, mental status changes


Treatment: Based on
determination of volume status.
Life-Threatening. (Seizures, coma) 3-5% NS can be given in the
ICU setting. Attempt to raise the sodium to about 125 mEq/L
with 3-5% NS.
Isovolemic Hyponatremia. (SIADH)
• Restrict fluids (1000-1500 mL/d).
• Demeclocycline can be used in chronic SIADH.
Hypervolemic Hyponatremia
• Restrict sodium and fluids (1000-1500 mL/d).
• Treat underlying disorder. CHF may respond to a combination of
ACE inhibitor and furosemide.
Hypovolemic Hyponatremia
• Give D5NS or NS.


Hypernatremia (Na+ >144 mEq/L
[mmol/L])

• Mechanisms: Most frequently, a deficit
of total body water.
• (Hypovolemic hypernatremia).
• (Isovolemic hypernatremia).
• (Hypervolemic hypernatremia).


[mmol/L])
• Mechanisms: Most frequently, a deficit of
total body water.
• Combined Sodium and Water Losses
(Hypovolemic hypernatremia).
• Water loss in excess of sodium loss
results in low total body sodium.
• Due to renal (diuretics, osmotic diuresis
due to glycosuria, mannitol, etc) or
extrarenal (sweating, GI, respiratory)
losses


[mmol/L])

• Excess Sodium (Hypervolemic
hypernatremia).
• Total body sodium increased, caused by
iatrogenic sodium administration (ie,
hypertonic dialysis, sodium-containing
medications) or adrenal hyperfunction
(Cushing’s syndrome,
hyperaldosteronism).


[mmol/L])

• Excess Water Loss (Isovolemic
hypernatremia).
• Total body sodium remains normal,
but total body water is decreased.
Caused by diabetes insipidus
,excess skin losses, respiratory
loss, others.


Hypernatremia

• Symptoms:
Depend on how rapidly the sodium level
has changed
• Confusion, lethargy, stupor, coma
• Muscle tremors, seizures
• Signs:
Hyperreflexia, mental status changes


Hypernatremia:
Treatment:
• Euvolemic/Isovolemic. (No orthostatic
hypotension) calculate the volume of free
water needed to correct the Na+ to normal
as follows:
• Body water deficit = Normal TBW - Current
TBW
Where Normal TBW = 0.6 x Body weight in kg
• And Current TBW =Normal serum sodium x
TBW / Measured serum sodium


Hypervolemic
Hypernatremia

• Avoid medications that contain
excessive sodium
(carbenicillin, etc).

Use furosemide along with D5W.


Hypernatremia:
Treatment:
• Hypovolemic Hypernatremia.
Determine if the patient volume is
depleted by determining if orthostatic
hypotension is present;
• if volume is depleted, rehydrate with
NS until hemodynamically stable,
• then administer hypotonic saline (1/2
NS).


Treatment of hypernatremia

• Hypotonic fluid loss is the most common form
of hypernatremia.
• It is caused by gastroenteritis, osmotic
diuresis.
• Signs of intravascular depletion are evident.
• Treatment involves replacement volume with
normal saline, followed by correction of the
free water deficit


Basal requirement of
Potassium

• K+ intake ranges from 40-150 mEq daily
• Homeostasis (minimum req) 20-30 mEq/day
• Increased requirement in heart failure and
hypertension


Relationship between serum K+ serum and
TBK at various levels of deficit and excess
10 -
-
8 -
-
6 -
serum K+ -
(meq/L) 4 -
-
2 -
-
-
-900 -600 -300 0 +300
K+ deficit (meq) K+ excess (meq)


Decreased serum K+
and deficit of TBK (%)
5 -
-
4 -
-
3 -
serum K+ -
(meq/L) 2 -
-
1 -
- total body K+ = 50 mEq/kg body weight
-
05 10 15 20 25 K+ deficit (%)


K+ and acid-base status
Blood pH 7.2 7.3 7.4 7.5 7.6 K+ depletion
5.0 4.5 4.0 3.5 3.0 0 mEq
Serum K+ 4.5 4.0 3.5 3.0 2.5 100 mEq
4.0 3.5 3.0 2.5 2.0 200 mEq
3.2 3.0 2.5 2.0 1.5 400 mEq

Acidosis Alkalosis

cell ECF DCC Cell ECF Tubulus distal

3 K+ 3 K+ H+ 3 K+ 3 K+
K+ K+
H+ H+ H+ H+ H+
2 Na + 2 Na + 2 Na + 2 Na +

Urine Urin
H + acid urine H+ Urine Alkali
K + low urine K+ K + K+ urin tinggi


Standard K+ concentration in i.v.
solutions
1 Cnc: <40 mEq/L
< 40mEq/L
2 Rate of adm: <20 mEq/hr KCl

3 daily dosage : <100 mEq/day
4 Monitor ECG and serum K+
5 U r i n e output: >0.5 ml/kg/hr

KCl bolus


Serum Electrolytes
MAGNESIUM
• common electrolyte abnormality hospitalized
humans is hypomagnesimia
• Primarily intracellular
• Low Mg may be clinically silent but makes
hypocalcemia and hypokalemia refractory to
treatment
• Vitamin D controls Mg absorption
• May see high Mg in renal failure


Serum Electrolytes
MAGNESIUM
• Normosol and Plasmalyte contain Mg
• Very low Mg may require treatment with IV
MgSO4
• Cofactor for NaK ATPase


Rate of administration of
Electrolyte & glucose
Na+ 100 mEq/hr

K+ 20 mEq/hr

Ca++ 20 mEq/hr

Mg++ 20 mEq/hr
-
HCO3 100 mEq/hr

Glucosa 0,5 gr/kg/hr ( 4 mg/kg/min)*

* Neonates 6-8 mg/kg/min


Conclusion
• Maintenance fluid therapy : normal loss
• (IWL + Urine)
• Suitable in hypertonic dehydration
• Minimized risk of potassium depletion in cases
of prolonged inadequate oral intake
• ‘Ready for use” product associated with less
risk of contamination
• Can be combined with amino acids


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