PATHOPHYSIOLOGY FLUIDS AND BLOODS
Critical Thinking
FLUIDS AND BLOOD
1. Explain the physiologic mechanisms of regulation of interstitial fluid.
The transfer of water between the vascular and interstitial compartments occurs
at the capillary level. Four forces control the movement of fluid.
- The capillary filtration pressure, which pushes water out of the capillary into
the interstitial spaces.
- The capillary colloid osmotic pressure, which pulls water back into the
capillary.
- The interstitial hydrostatic pressure, which opposes the movement of water
out of the capillary.
- The tissue colloid osmotic pressure, which pulls water out of the capillary
into the interstitial spaces.
The combination of these four forces is such that only a small excess of fluid
remains in the interstitial compartment. This excess fluid is removed from the
interstitium by the lymphatic system and returned to the systemic circulation.
2. Describe the pathophysiologic mechanisms of edema formations.
Edema is the accumulation of fluid in the extracellular fluid space.
Factors precipitating Edema:
● Increased capillary hydrostatic pressure as (Heart Failure)
● Decreased plasma oncotic pressure (Malnutrition)
● Increased capillary permeability (Inflammation)
● Lymphatic obstruction
, INFLAMMATION
Capillary endothelial injury by toxins/ histamine/ anoxia
↓
Endothelial gap
↓
Increased capillary permeability to plasma proteins
↓
Decreased plasma oncotic pressure
↓
Edema
3. Discuss the effects and classification of edema.
● Peripheral Edema – commonly affects arms and legs, ankles and hands.
Common and early signs are:
- Arms and legs starts to look swollen
- Difficulty in moving
- Arms and legs starts feeling heavy
- Sensation and pain near the edema
● Pulmonary Edema – affects lungs by causing excess fluid in the numerous air sacs
in the lungs, making breathing difficult. When pulmonary edema develops
immediate care and treatment is needed because it can lead to congestive heart
failure, respiratory failure and death.
Signs are:
- Dyspnea
- Feeling of drowning when lying down
- Wheezing breath
- Irregular heartbeat
● Cerebral Edema – also called brain swelling because it causes fluid to develop in
our brain. Increased fluid inside the skull reduces brain blood flow and oxygen that
our brain needs. It can be fatal and irreversible if left untreated.
Signs and symptoms are:
- Lack of coordination
- Dizziness
- Nausea
- Headache
- Seizures
● Macular Edema – swelling occurs in the macula that affects our central vision.
Primary symptoms are:
- Blurry vision - Vision for color appears faded
- Wavy vision - Loss of vision
Critical Thinking
FLUIDS AND BLOOD
1. Explain the physiologic mechanisms of regulation of interstitial fluid.
The transfer of water between the vascular and interstitial compartments occurs
at the capillary level. Four forces control the movement of fluid.
- The capillary filtration pressure, which pushes water out of the capillary into
the interstitial spaces.
- The capillary colloid osmotic pressure, which pulls water back into the
capillary.
- The interstitial hydrostatic pressure, which opposes the movement of water
out of the capillary.
- The tissue colloid osmotic pressure, which pulls water out of the capillary
into the interstitial spaces.
The combination of these four forces is such that only a small excess of fluid
remains in the interstitial compartment. This excess fluid is removed from the
interstitium by the lymphatic system and returned to the systemic circulation.
2. Describe the pathophysiologic mechanisms of edema formations.
Edema is the accumulation of fluid in the extracellular fluid space.
Factors precipitating Edema:
● Increased capillary hydrostatic pressure as (Heart Failure)
● Decreased plasma oncotic pressure (Malnutrition)
● Increased capillary permeability (Inflammation)
● Lymphatic obstruction
, INFLAMMATION
Capillary endothelial injury by toxins/ histamine/ anoxia
↓
Endothelial gap
↓
Increased capillary permeability to plasma proteins
↓
Decreased plasma oncotic pressure
↓
Edema
3. Discuss the effects and classification of edema.
● Peripheral Edema – commonly affects arms and legs, ankles and hands.
Common and early signs are:
- Arms and legs starts to look swollen
- Difficulty in moving
- Arms and legs starts feeling heavy
- Sensation and pain near the edema
● Pulmonary Edema – affects lungs by causing excess fluid in the numerous air sacs
in the lungs, making breathing difficult. When pulmonary edema develops
immediate care and treatment is needed because it can lead to congestive heart
failure, respiratory failure and death.
Signs are:
- Dyspnea
- Feeling of drowning when lying down
- Wheezing breath
- Irregular heartbeat
● Cerebral Edema – also called brain swelling because it causes fluid to develop in
our brain. Increased fluid inside the skull reduces brain blood flow and oxygen that
our brain needs. It can be fatal and irreversible if left untreated.
Signs and symptoms are:
- Lack of coordination
- Dizziness
- Nausea
- Headache
- Seizures
● Macular Edema – swelling occurs in the macula that affects our central vision.
Primary symptoms are:
- Blurry vision - Vision for color appears faded
- Wavy vision - Loss of vision
