Fluids

[John]

Fluids

Compartments
Total body water          = 60%  body weight
ICF                             = 40%    
ECF                            = 20%   

   Interstitial fluid 
   Plasma   
   Transcellular
   Water moves freely between these compartments

ECF is further divided by the Transcellular compartment
Accumulation of fluid in the transcellular compartment

Compartments
A. Hypertonic solution has high solute concentration
    and therefore a low water concentration.

B. Hyportonic solution has low solute concentration
    and therefore a high water concentration.

C. Water moves from a hypertonic solution to a hypotonic solution.

ICF & ECF
K+
HCO3-
HPO42-
SO42-
Protein anions
Volume controlled by [K+]

Na+
Cl-
HCO3-
Volume controlled by [Na+]

Plasma
Volume controlled by balance between hydrostatic and colloid osmotic pressure.  

A. capillary filtration 
- pushes water out of capillary into interstitial spaces

(arterarl and venous pressures, precapillary and postcapillary resistance, the forcde of gravity).

B. Tissur hydrostatic pressure
- pulls water out of capillary into the tissue space.

C. capillary colloidal osmotic pressure.
- pulls water back into the capillary

D. interstial fluid pressure
- opposess the movementof water out of the capillary.
Protein mostly responsible is albumin

Oedema
Increased hydrostatic pressure

Increased vascular volume (heart failure, kidney disease, premenstral sodium retention, pregnancy, environmental heat stress).

Venous obstruction (liver disease with potal vein obstruction, acute pulmonary edema, venous thrombosis)

Decreased arteriolar resistance ( calcium channel blocking, drug responses)

Decreased capillary colloid osmotic pressure

Increased loss of plasma proteins (protein losing kidney disease, extensive burns)

Decreased production of plasma proteins. (liver disease, starvation, malnutrition).

Increased capillary permeability

Inflammation, allergic reaction, malignancy, tissur injury and burns.

Or any combination of these

Isotonic fluid volume deficit

Causes

Inadequate intake

Excessive GI losses

Excessive skin losses

Third space losses

Manifestations

Acute Weight loss

Thirst

Urine

Serum

Cardiovascular

ECF loss

Body Temperature

Isotonic fluid excess
Causes

Inadequate Na+ and H2O elimination
Excessive Na+ intake in relation to output
Excessive fluid intake in relation to output

Manifestations

Acute weight gain
Increased ECF volume
Increased vascular volume

From capillaries to interstitial space
A. water is carried to tissues in arterial blood.

B. The pressure in arterial blood is relatively high.

C. As the blood enters the fine thin walled capillaries,
    some of the fluid is forced out into the interstitial spaces
    by hydrostatic pressure.

From interstitial spaces into the Circulatory system.
A. as the water moves from the capillaries into the interstitial
spaces, the concentration of water in these spaces increases
while that in the capillaries decreases.

Thus some of the water forced out of the arterial end of the capillary is reabsorbed onto the distal end by the process of Osmosis.

B. The rest of the excess fluid enters the lymph vessels,
is eventually returned to the venous system.

Reduction in the extracellular fluid volume.
A. from the vascular compartment
     bleeding, hamorrages

B. from the interstitial spaces
     sweating, burn, exercise.

C. as a loss from the gastrointestinal tract
     diarrhea, decreased volume.

Movement of fluid between the etracellular compartment and the intracelluar compartment.

1. Water moves between the interstitial spaces and the inside of the cells by the process of osmosis. 
   

The factor influencing the direction of movement is Osmotic pressure, concentration move.

2. When the extracellular fluid becomes more dilute than the fluid in the cells, the net movement of water will be into the cells. 
   

If the extracellular fluid becomes more concentrated than the fluid in the cells, water will move out of the cells.

Mr. Kendall had been vomiting for several days. 

His urine output decreased. 

He was given 1 litre of 5% dextrose in water and then 1 litre of 5% dextrose in normal saline (0.9% NaCl)

1  In his adult stage, Mr.  Kendall's body water represents 60 % of his total body weight. 

What percentage of his total body weight is in the intracellular compartment 40 %

What percent of water is in the extracellular compartment?  20 %

2  Explain why Mr.  Kendall's urine output is decreased. 
    Mr Kendall is losing body fluid from vomiting, a lack of fluid intake.

3  The three primary sources for water intake are liquid, food, and oxidation of food.

4  Vomiting caused Mr. Kendall to lose body fluids, caused a decrease in urine output. 
   

The solute concentration was increased due to less circulating body fluid. 
    

As a result of an increased solute concentration, the posterior pituitary gland will release more ADH

5  Mr. Kendall received 1 litre of 5% dextrose in water, 
which has a similar osmolality as plasma.  
  

A solution with osmolality similar to that of plasma is considered to be iso-osmolar or isotonic.
 
6  The second litre he received was 5% dextrose in normal saline.  This solution is a(n) hyperosmolar or hypertonic  solution.

7  The osmolality of plasma is 290 mOsm.  A solution with less than 240 mOsm is considered hypo-osmolar or hypotonic.

8  One-half of normal saline (0.45%) NaCl solution has 155 mOsm. 

What is this type of solution?  Hypo-osmolar or hypotonic. 

Mr.  Kendall developed oedema of the lower extremities.

Laboratory results documented a lower than normal serum
    protein.

9  Factors regulating the flow of body constituents between the
    interstitial and intravascular compartments are:
    hydrostatic pressure, tissue pressure, colloid osmotic pressure,
    tissue colloid osmotic pressure.

10  Define the following four terms
 (a) Pressure gradient 
     difference in pressure between two point in a fluid
 (b) Crystalloids diffusible substances
 (c) Colloids       nondiffusible substances
 (d) Albumin most important osmotically active protein

11  Pressure gradients are responsible for the exchange of fluid
      between the capillaries and the tissues

12  The amount of colloid osmotic pressure that develops depends on the concentration of non diffusible substances such as protein or albumin

13  The direction of movement of fluid depends on the results of the opposing forces.

(a) The hydrostatic pressure is greater than the colloid osmotic pressure at the arterial end of the capillary; thus the fluid moves out of the capillaries and into the surrounding tissues

(b) The osmotic pressure is greater than the hydrostatic pressure at the venous end of the capillary; thus the fluid moves out of the tissues and re-enters the capillary

14  Mr.  Kendall's decrease in serum protein could account for his oedema

15  Mr. Kendall has a venous obstruction due to varicosities.  
     

This causes an increase in venous hydrostatic pressure, preventing fluid from moving out of tissues and into the circulation.  
     

Explain what happens to this fluid. The fluid accumulates in the tissue 
causing oedema

Disturbance in fluid balance
1. Gastroenteritis
2. Fever
3. Acute inflammation
4. Hyperventilation
5. Congestive heart failure
6. Full thickness burns
7. Exercise
8. Diabetes mellitus

1.vomiting, diarrhea
2. Sweating
3. Dehydration
4. Excessive breathing
5. Urination
6. Dehydration,
7. Sweating
8. Urination.

Tom Fellows is a 67-year-old single Caucasian man who until recently lived alone in his own house. 

He now lives in an intermediate care unit of a continuing care facility where his meals are provided. 

He is independent in activities of daily living but requires help with shopping and money management.

He was a financial analyst who led an active social life, which included almost nightly "happy hours" with work associates until his retirement 5 years ago.

After his retirement he started to drink alone.

He quit going to the dining room for his meals and gradually stopped drinking fluids other than his beer and wine.

The nurse on the day shift recorded his vital signs as temperature 37.2OC, pulse 104, and respirations 28.

His laboratory studies revealed an elevated haemoglobin and haematocrit.

Other laboratory studies revealed serum potassium, 3.4 mEq/L; serum Na, 147 mEq/L; and Cl, 105 mEq/L. 

His skin and mucous membranes were very dry. He complained of constipation.

1  From this history, identify three fluid problems.
    Dehydration, oedema, and constipation.

2  What is the clinical source of Mr. Fellows' dehydration?
    Insufficient water intake (or decreased thirst mechanism)

3  Identify four clinical signs and symptoms of dehydration
    experienced by Mr. Fellows:

 (a)  vital signs:  temperature slightly elevated, pulse and respirations elevated
 (b)  Hgb, Hct and BUN elevated
 (c)  serum sodium elevated
 (d)  skin and mucous membranes dry

4  Is it possible to have dehydration and oedema at the same time?
    Yes

Explain 

A person can have hypovolaemia in the vascular system with increased fluid in the interstitial spaces – effectively a shift from the vascular compartment to the IF compartment.

Mr. Fellows was given intravenous fluids for several days and then later given tube feedings daily. 

5  While Mr. Fellows was receiving intravenous fluids, identify at least two nursing interventions aimed at maintaining an appropriate fluid balance for clients receiving intravenous fluids.  
 

Assess the intravenous fluid according to the type ordered and its osmolarity, adjust the rate according to the client’s age and physiological state assess fluid intake and output – fluid balance.

6  If Mr. Fellows receives continuous intravenous replacements
with 5% dextrose in water, what type of fluid problem might result?  
   

Water intoxication or over hydration

7  If the intravenous fluids were administered too rapidly, what type of fluid imbalance is Mr. Fellows most likely to develop?  
  

Hypervolaemia or isotonic fluid excess.

Identify three symptoms of this imbalance. 

Acute weight gain, Full, bounding pulse, Shortness of bearth.                    

For others see p 762 in seventh edition of Porth

8   Tube feedings high in carbohydrate can cause what type of a fluid problem?
     

diarrhoea

9    The normal potassium level in the aged is  poorly conserved, and therefore fluid imbalances often result in a potassium deficit called hypokalaemia.

10  Fluid imbalances can cause Mr. Fellows to be at an increased risk for skin breakdown.