Fluid volume deficit, excess and water intoxication

Fluid Volume Disturbances

• Fluid Volume Deficit (Hypovolemia)

Fluid Volume Deficit

• Mild – 2% of body weight loss

• Moderate – 5% of body weight loss

• Severe – 8% or more of body weight loss

THREE TYPES OF deficit

• Hyperosmolar fluid volume deficit- water loss is greater than the electrolyte loss

• Isosmolar fluid volume deficit – equal proportion of fluid and electrolyte loss

Fluid Volume Deficit

• Pathophysiology – results from loss of body fluids and occurs more rapidly when coupled with decreased fluid intake

Fluid Volume Deficit

• Clinical manifestations- Acute weight loss- Decreased skin turgor

Fluid Volume Deficit

- Oliguria - Concentrated urine - Postural hypotension - Weak, rapid, heart rate - Flattened neck veins - Increased temperature - Decreased central venous pressure

ETIOLOGY AND RISK FACTORS• Severe vomiting • Traumatic injuries• Ileostomy• Burns

• Use of diuretics

LABORATORY FINDINGS

• Increased osmolality(> 295 mOsm/ kg)• Increase BU (>25 mg / L )• Elevated hematocrit (> 55%) • Increased specific gravity of urine ( > 1.030)

MANAGEMENT

Management of fluid in patient with fluid deficit should aim at

Replacing deficitCorrecting ongoing lossesMaintenance

Management of mild deficit

• Mild fluid volume loss can be corrected with oral fluid replacement

Management of moderate/severe volume deficit

• IV fluids needed

• Fluid Volume Excess (Hypervolemia)

Fluid Volume Excess

• Pathophysiology – may be related to fluid overload or diminished function of the homeostatic mechinisms responsible for regulating fluid balance

ETIOLOGY AND RISK FACTORS

• Heart failure• Renal disorders• Cirrhosis of liver• Increased ingestion of high sodium foods• Excessive amount of IV fluids containing sodium• Electrolyte free IV fluids• SIADH,Sepsis• decreased colloid osmotic pressure• lymphatic and venous obstruction • Cushing’s syndrome & glucocorticoids

Why does heart failure leads to oedema

• Reduced renal perfusion--- activates renin angiotensin aldosterone mechanism---- results in fluid retention

Why does renal failure cause oedema?

• Why does liver failure cause oedema

CLINICAL MANIFESTATION

• Dyspnea & crackles in lungs• pleural effusion• Neck veins prominant• Bounding pulse &elevated BP• Pitting & sacral edema• Weight gain• Increased CVP• Change in level of consciousness

Fluid Volume Excess

LAB INVESTIGATION

• serum osmolality <275mOsm/ kg• Decreased hematocrit [ < 45%]

MANAGEMENT

• Diuretics• Restrict fluids• In people with HF, ACE inhibitors• A low sodium diet

Water intoxication

• At the onset of this condition fluid outside the cells has an excessively low amount of solutes in comparison to inside the cells, the fluid shifts through osmosis into the cells in order to balance its concentration.

• This causes the cells to swell. In the brain, this swelling increases ICP

features

• headache• personality changes• changes in behavior, confusion, irritability• difficulty breathing during exertion• cramping, nausea, vomiting, • seizures, brain damage, coma or death due to

cerebral oedema

Risk factors

• Psychiatric conditions-polydipsia• Over replacement of IV fluids • Heat stress

management

• Restriction of fluids is sufficient in mild cases• If severe diuretics needed

Thank you!!