Transcript Document

Body fluids IV
Content areas
• Fluid disturbances & compensatory
mechanisms
• Changes in volume and electrolytes in
– Diarrhoea
– Vomiting
• Importance of rehydration
• Fluids used for rehydration
– Limitations/ risks involved with their use
• Usefulness of fluids in replacing lost fluid
WATER BALANCE
ICF
28 L
ECF
14 L
Skin
500ml
Lungs
400ml
Urine 1,500ml
Faeces
100ml
2,500ml
Ingested fluid 1,300ml
Solids
800ml
Metabolic water 400ml
2,500ml
Causes of fluid loss
•
•
•
•
Skin
GIT
Kidney Haemorrhage,
burns, large wounds
Diarrhoea, vomiting …
Polyuria, diuretics
oedema ……
Transpiration / Insensible loss
- Inevitable loss
- Depends on
environment
integrity of skin
- The evaporation of water from skin
- 500-750 ml/day
- Loss of electrolytes is negligible
(Perspiration – visible excretion)
Breathing
Inevitable loss
24 hr transcellular fluid secretion into the
gut by an adult
Saliva
1,500 ml
Gastric juice
2,500 ml
Bile
500 ml
Pancreatic juice
700 ml
Succus entericus 3,000 ml
8,200 ml
Faeces
100 ml
 Diarrhoea & vomiting can alter water
balance
Kidneys
- 180 L of fluid passes into the Bowman’s
space daily
- Average daily urine output is 1000 mL
(500 mL of urine – obligatory loss)
The balance depends on intake
 Kidney disease can effect water balance
Dehydration & overhydration
Key words
Symptoms - What the patient tells us
Signs
- What we find out by examining the
patient
Dehydration
- Loss of body water
Over hydration - Excess of body water
Dehydration
↓ in ECF volume due to loss of H2O & Na+
Symptoms
- Dry throat & mouth
- Lethargy
- Weight loss
- Difficulty in speech
- ↓ urine output
Signs
- ↓ Skin turgor
- Dry lips and tongue
- Flat neck veins
- ↓ Blood pressure
- Sunken eye balls
- Sunken fontanelle(in infants)
- ↑ Heart rate and pulse rate
Over hydration
• Puffy eyelids
• Bulging fontanelle (in infants)
• Oedema
• Weight gain
………..
Dehydration States
• Isosmotic dehydration
• Hyperosmotic dehydration
• Hypo-osmotic dehydration
Isosmotic Dehydration
↓ Plasma volume –
Blood loss (hemorrhage)
Diarrhoea and vomiting
Burns
Mechanism
Loss of fluid from plasma
Intestines
Plasma
ISF
loss from interstitium
ECF volume
no change in osmolality
- No shift of fluid into/out of ICF
ICF
Treatment – isotonic saline
Hyperosmotic Dehydration
Loss of water in excess of salt
Causes
a)
b)
c)
d)
e)
f)
↓ Water intake
Diabetes insipidus -  loss of water from kidney
Diabetes mellitus
Alcoholism
Fever
Excessive sweating
Mechanism
i.
Loss of fluid from plasma (water > solutes)
Hyperosmotic plasma
Fluid moves from interstitium
ii.
Plasma
Osmolality of interstitial fluid
Fluid moves from ICF
in ECF & ICF volumes
in osmolality of ECF & ICF
ECF
Hyposmotic Dehydration
• Solute loss in excess of water
•
Causes
Renal loss of NaCl due to
Adrenal insufficiency (Addison’s disease)
Mechanisms
i. Loss of NaCl from plasma
Plasma osmolality
ii.
Fluid moves from plasma
Interstitial osmolality
Fluid moves from ECF
ECF volume , ICF volume
Osmolality in ECF & ICF
interstitium
ICF
Overhydration
Isosmotic overhydration
Causes
a) Oral/IV administration of large volume of
isotonic normal saline (0.9 % NaCl)
Mechanism
I.
ECF volume ↑
II. No change in osmolality of ECF/ ICF
Treatment
Diuretics
Hyperosmotic overhydration
Causes
a) Oral/IV administration of large volume of hypertonic saline
Mechanism
I.
Plasma osmolality
II.
Fluid moves from interstitium
Interstitial osmolality
II.
Fluid flow from ICF
ICF & ECF volume
ICF & ECF osmolality
Plasma
ECF
Hypo-osmotic overhydration
Intake of water exceeds the excretory capacity of
kidney
Causes
a) Ingestion of large volume of water
b) Retention of H2O by kidney (SIADH)
Syndrome of inappropriate secretion of ADH
(ADH – anti diuretic hormone)
Mechanism
I.
Plasma osmolality
Fluid flows from plasma
Interstitium
Osmolality of Interstitium
II. Fluid
III.
flows from plasma ECF
ICF & ECF volume
ICF & ECF osmolality
ICF
Volume & Osmolality in ECF & ECF
NMS_ DIAGRAM
Volume & Osmolality in ECF & ECF
NMS_ DIAGRAM
Volume & Osmolality in ECF & ECF
Metabolic consequences of VOMITING
Gastric juice
Isotonic with plasma
[Cl-], [K+]
Very high [H+]
Therefore net result of vomiting,
a) Isotonic dehydration
b) Acid loosing Alkalosis
c) Hypochloraemia
d) Hypokalaemia
e) Hypovolaemia
Metabolic consequences of DIARRHOEA
Intestinal, pancreatic, biliary & colonic secretions
Isotonic with plasma
[Na+], [K+], [HCO -]
3
Therefore net result of diarrhoea,
a) Isotonic dehydration
b) Base loosing Acidosis
d) Hypokalaemia
e) Hypovolaemia
 Diarrhoea & vomiting in infants & children
- Serious problem
- Total deprivation of food & H2O
Adults
Children
Survive > 10 days
Survive < 3 days
Reasons
1. Absolute volume of water in ECF - child < adult
2. Water distribution
TBW
ICF
ECF
Adult
55-60%
2/3
1/3
Children
65-70%
1/2
1/2
Fluid is lost more rapidly
1/7 exchanged
1/2 exchanged
3. Infants kidney is less efficient
- Response to ADH & Aldosterone is less
therefore reabsorption of fluids is
- Treatment must be prompt & efficient
a) Assess the level of dehydration
b) Rehydrate accordingly
Rehydration Solutions
1. Oral Rehydration solution (ORS)
‘Jeewani’
-NaCl - 3.5g
-Na Citrate – 2.9g 1L of H O
2
-KCl – 1.5g
-Glucose 20g
2. Blood
 Whole blood
 Plasma
 Packed cells
Disadvantages
Diseases (hepatitis B, HIV)
Allergies
3. Intravenous solutions
a. Colloids
Dextran, Gelafundin
Maintains /increases plasma oncotic pressure
helps draw fluid into the intravascular
compartment
Disadvantages
• Coagulation problems
• Adverse reactions
• Expensive
b. Crystalloids
 Normal saline (0.9% NaCl)
 Hartmann’s solution (Ringer lactate)
Isotonic solution
 Glucose (Dextrose) - 5% , 10%
↑ ECF space
Proportional distribution of fluid into
different compartments
• Infusion of 1L of normal saline
1L will remain in the ECF
1/4 in plasma
¾ in interstitial fluid
• Infusion of 1L of colloid
1L remain in plasma
• Infusion of 1L of 5% dextrose
1/3 rd in ECF
2/3 rd in ICF