Body fluids IV

Content areas Fluid disturbances & compensatory mechanisms Fluid disturbances & compensatory mechanisms Changes in volume and electrolytes in Changes in volume and electrolytes in –Diarrhoea –Vomiting Importance of rehydration Importance of rehydration Fluids used for rehydration Fluids used for rehydration –Limitations/ risks involved with their use Usefulness of fluids in replacing lost fluid Usefulness of fluids in replacing lost fluid

WATER BALANCE Ingested fluid 1,300ml Ingested fluid 1,300ml Solids 800ml Solids 800ml Metabolic water 400ml Metabolic water 400ml 2,500ml 2,500ml Skin 500ml Skin 500ml Lungs 400ml Lungs 400ml Urine 1,500ml Urine 1,500ml Faeces 100ml Faeces 100ml 2,500ml 2,500ml ICF 28 L ECF 14 L

Causes of fluid loss Skin - burns, large wounds Skin - burns, large wounds GIT -Diarrhoea, vomiting … GIT -Diarrhoea, vomiting … Kidney -Polyuria, diuretics Kidney -Polyuria, diuretics Haemorrhage, oedema …… Haemorrhage, oedema ……

Transpiration / Insensible loss - Inevitable loss - Depends on environment integrity of skin integrity of skin - The evaporation of water from skin ml/day - Loss of electrolytes is negligible (Perspiration – visible excretion) (Perspiration – visible excretion) Breathing Inevitable loss Breathing Inevitable loss

24 hr transcellular fluid secretion into the 24 hr transcellular fluid secretion into the gut by an adult gut by an adult Saliva 1,500 ml Saliva 1,500 ml Gastric juice 2,500 ml Gastric juice 2,500 ml Bile 500 ml Bile 500 ml Pancreatic juice 700 ml Pancreatic juice 700 ml Succus entericus 3,000 ml Succus entericus 3,000 ml 8,200 ml 8,200 ml Faeces 100 ml Faeces 100 ml  Diarrhoea & vomiting can alter water balance balance

Kidneys Kidneys L of fluid passes into the Bowman’s space daily - Average daily urine output is 1000 mL (500 mL of urine – obligatory loss) (500 mL of urine – obligatory loss) The balance depends on intake 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 patient Dehydration- Loss of body water Over hydration- Excess of body water

Dehydration ↓ in ECF volume due to loss of H 2 O & Na + Symptoms - Dry throat & mouth- Difficulty in speech - Lethargy- ↓ urine output - Weight loss Signs - ↓ Skin turgor - Sunken eye balls -Dry lips and tongue - Sunken fontanelle(in infants) -Flat neck veins- ↑ Heart rate and pulse rate -↓ Blood pressure

Over hydration Puffy eyelids Puffy eyelids Bulging fontanelle (in infants) Bulging fontanelle (in infants) Oedema Oedema Weight gain Weight gain……….. Osmolality Number of osmoles/Kg of solvent Osmolality Number of osmoles/Kg of solvent Osmolarity –Number of osmoles/Liter of solvent Osmolarity –Number of osmoles/Liter of solvent Tonicity of fluids Tonicity of fluids Osmotically active particalls ab=nd volume homeostasis Homeostasis –maintenance of the interior of the body in a stable state Osmotically active particalls ab=nd volume homeostasis Homeostasis –maintenance of the interior of the body in a stable state Fluid volume is mainly determined by the total amount of osmotically active particals on the compartment Fluid volume is mainly determined by the total amount of osmotically active particals on the compartment Osoticallly active particals fluid volume Osoticallly active particals fluid volume

Dehydration States Isosmotic dehydration Isosmotic dehydration Hyperosmotic dehydration Hyperosmotic dehydration Hypo-osmotic dehydration Hypo-osmotic dehydration

↓ Plasma volume –Blood loss (hemorrhage) Diarrhoea and vomiting BurnsMechanism Loss of fluid from plasma loss from interstitium ECF volume no change in osmolality ECF volume no change in osmolality - No shift of fluid into/out of ICF - No shift of fluid into/out of ICF Treatment – isotonic saline Treatment – isotonic saline Isosmotic Dehydration ICF ICF ISF PlasmaIntestines

Hyperosmotic Dehydration Loss of water in excess of salt Causes a)↓ Water intake b)Diabetes insipidus -  loss of water from kidney c)Diabetes mellitus d)Alcoholism e)Fever f)Excessive sweating

Mechanism i. Loss of fluid from plasma (water > solutes) Hyperosmotic plasma Hyperosmotic plasma Fluid moves from interstitium Plasma Fluid moves from interstitium Plasma ii. Osmolality of interstitial fluid Fluid moves from ICF ECF Fluid moves from ICF ECF in ECF & ICF volumes in ECF & ICF volumes in osmolality of ECF & ICF in osmolality of ECF & ICF

Hyposmotic Dehydration Solute loss in excess of water Solute loss in excess of water Causes Causes Renal loss of NaCl due to Renal loss of NaCl due to Adrenal insufficiency (Addison’s disease ) Adrenal insufficiency (Addison’s disease )

Mechanisms i. Loss of NaCl from plasma Plasma osmolality Plasma osmolality Fluid moves from plasma interstitium ii. Interstitial osmolality Fluid moves from ECF ICF ECF volume, ICF volume ECF volume, ICF volume Osmolality in ECF & ICF Osmolality in ECF & 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 Diuretics

Hyperosmotic overhydration Causes a) Oral/IV administration of large volume of hypertonic saline Mechanism I. Plasma osmolality Fluid moves from interstitium Plasma Fluid moves from interstitium Plasma II. Interstitial osmolality Fluid flow from ICF ECF Fluid flow from ICF ECF II. ICF & ECF volume ICF & ECF osmolality ICF & ECF osmolality

Hypo-osmotic overhydration Intake of water exceeds the excretory capacity of kidney Causes a) Ingestion of large volume of water b) Retention of H 2 O by kidney (SIADH) Syndrome of inappropriate secretion of ADH Syndrome of inappropriate secretion of ADH (ADH – anti diuretic hormone) (ADH – anti diuretic hormone)

Mechanism I. Plasma osmolality Fluid flows from plasma Interstitium Fluid flows from plasma Interstitium Osmolality of Interstitium Osmolality of Interstitium II. Fluid flows from plasma ECF ICF III. ICF & ECF volume ICF & ECF osmolality ICF & ECF osmolality

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 Gastric juice Isotonic with plasma [Cl - ], [K + ] [Cl - ], [K + ] Very high [H + ] Very high [H + ] Therefore net result of vomiting, a) Isotonic dehydration a) Isotonic dehydration b) Acid loosing Alkalosis b) Acid loosing Alkalosis c) Hypochloraemia c) Hypochloraemia d) Hypokalaemia d) Hypokalaemia e) Hypovolaemia e) Hypovolaemia

Metabolic consequences of DIARRHOEA Intestinal, pancreatic, biliary & colonic secretions Isotonic with plasma [Na + ], [K + ], [HCO 3 - ] [Na + ], [K + ], [HCO 3 - ] Therefore net result of diarrhoea, a) Isotonic dehydration a) Isotonic dehydration b) Base loosing Acidosis b) Base loosing Acidosis d) Hypokalaemia d) Hypokalaemia e) Hypovolaemia e) Hypovolaemia

 Diarrhoea & vomiting in infants & children - Serious problem - Serious problem - Total deprivation of food & H 2 O - Total deprivation of food & H 2 O Adults Survive > 10 days Adults Survive > 10 days Children Survive < 3 days Children Survive < 3 days

Reasons 1. Absolute volume of water in ECF - child < adult 2. Water distribution 1/7 exchanged 1/7 exchanged 1/2 exchanged 1/2 exchanged Fluid is lost more rapidly Fluid is lost more rapidly TBW TBWICFECF Adult55-60% 2/3 2/3 1/3 1/3 Children65-70% 1/2 1/2

3. Infants kidney is less efficient - Response to ADH & Aldosterone is less therefore reabsorption of fluids is - Response to ADH & Aldosterone is less therefore reabsorption of fluids is - Treatment must be prompt & efficient a) Assess the level of dehydration a) Assess the level of dehydration b) Rehydrate accordingly b) Rehydrate accordingly

Rehydration Solutions 1. Oral Rehydration solution (ORS) ‘Jeewani’ ‘Jeewani’ -NaCl - 3.5g -NaCl - 3.5g -Na Citrate – 2.9g -Na Citrate – 2.9g -KCl – 1.5g -KCl – 1.5g -Glucose 20g -Glucose 20g 1L of H 2 O

2.Blood  Whole blood  Plasma  Packed cells Disadvantages Diseases (hepatitis B, HIV) Allergies

a. Colloids a. Colloids Dextran, Gelafundin Dextran, Gelafundin Maintains /increases plasma oncotic pressure Maintains /increases plasma oncotic pressure helps draw fluid into the intravascular compartment helps draw fluid into the intravascular compartment 3. Intravenous solutions

Disadvantages Coagulation problems Coagulation problems Adverse reactions Adverse reactions Expensive Expensive

b. Crystalloids  Normal saline (0.9% NaCl)  Hartmann’s solution (Ringer lactate) Isotonic solution Isotonic solution  Glucose (Dextrose) - 5%, 10% ↑ ECF space

Proportional distribution of fluid into different compartments Infusion of 1L of normal saline Infusion of 1L of normal saline 1L will remain in the ECF 1L will remain in the ECF 1/4 in plasma 1/4 in plasma ¾ in interstitial fluid ¾ in interstitial fluid

Infusion of 1L of colloid Infusion of 1L of colloid 1L remain in plasma 1L remain in plasma Infusion of 1L of 5% dextrose Infusion of 1L of 5% dextrose 1/3 rd in ECF 1/3 rd in ECF 2/3 rd in ICF 2/3 rd in ICF