Test 1 (Body Fluids CIS) Flashcards
ISOSMOTIC Volume Contraction/ EXPANSION
- Osmolarity remains the same in ECF and ICF
- Only changes ECF Volume (ICF remain unchanged)
Examples:
- Vomiting
- Diarrhea
- Hemorrhage
- INFUSION of 0.9% NaCl!!!!!!!
Hyperosmotic Volume Contration (LOSS of WATER)
- Osmolarity of ECF INCREASES as ECF Volume DECREASES
- ICF Volume DECREASES as Water shifts from ICF to Equilibrate Osmolarity
Examples:
- Dehydration
- Diabetes
- Insipidus (Excessive Thirst)
Hyperosmotic Volume EXPANSION (GAIN of NaCl)
- Osmolarity of ECF INCREASES as ECF Volume INCREASES
- ICF Volume DECREASES as Water shifts from ICF to Equilibrate Osmolarity
Examples:
- Excess NaCl intake
- Mannitol Infusion
Hyposmotic Volume CONTRACTION (LOSS of NaCl)
- Osmolarity fo ECF DECREASES as ECF Volume DECREASES
- ICF Volume Increases
Examples:
- Hypoalsoswteronism
- Adrenal Insufficiency
Hyposmotic Volume EXPANSION (GAIN of Water)
- Addition of PURE WATER DECREASES ECF Osmolarity
- Water proportionately INCREASES ECF and ICF Volumes
Examples:
- SIADH
- Psychogenic Polydipsia
Sweat
- A dilute (HYPOTONIC) fluid containing low concentration of Na+ and K+
- Primarily WATER Loss (DEHYDRATION!!!!!!!!!)
What does the body systems do to address the Dehydration?
INCREASE:
- ADH (Osmoregulatory)
- Thirst (Osmoregulatory)
- SNS (Volume Regulation)
- RAAS (Volume Regulation)
DECREASE:
- ANP (Generates Na+ LOSS)
Elevation in BUN but no elevation in Creatinine levels
- If you see an Elevatino in BUN but not an elevation in Creatinine, this means the patient is DEHYDRATED!!!
BUN/ Creatinine is greater than 20 to 1, this is called a Pre-Renal Cause of BUN!!! (Aka Dehydration)
Hypovolemia
- Loss of Water and shows up as a low BP/ loss of water weight
- Can lose Na+ along with the Water!!!
NaCl Depletion
- Hyponatremia: Loss of NaCl
- Weight Loss
- Blood pressure
- BUN/ Creatinine Ration: Significance of elevation Ratio?
- Significane of no Neurologic Findings? Relationship to plasma Na?
How does a patient address Hypovolemia?
INCREASE:
- ADH (Osmoregulatory)
- Thirst (Osmoregulatory)
- SNS (Volume Regulation)
- RAAS (Volume Regulation)
DECREASE:
- ANP (Volume Regulation)
Hypovolemia
- Release of ADH with resulting high Urine Osmolarity
- Would result in exaggerated Hyponatremia due to WATER Retention
HYPONATREMIA:
- Elevated Renin, Angiotensin, Aldosterone, and low ANP with Low Urinary Na Excretion
***This patient’s Na is LOW, but not as low as expected… possibly due to LACK of WATER INTAKE by Patient
**Not LOW ENOUGH to cause Significant problems (Primarily Neurologic Issues)
Significance of a patient’s Blood Pressure at 70/50 after being in an accident
- HYPOTENSION in this patient is probably due to a LARGE VOLUME of Blood Loss due to his accident
***Blood is ISOSMOTIC therefore the Osmolatiry will not change in the ECF but the Volume of the ECF will DECREASE while everything in the ICF stays the same!!!
Effects of adding Either NaCl, Water, or Isotonic Saline
NaCl:
1) Plasma Na
- INCREASE
2) ECF Volume:
- INCREASE
3) Urine Na:
- INCREASE
4) ICF Volume:
- DECREASE
5) ADH:
- DECREASE
H2O:
1) Plasma Na
- DECREASE
2) ECF Volume:
- INCREASE
3) Urine Na:
- INCREASE
4) ICF Volume:
- INCREASE
5) ADH:
- DECREASE
Isotonic Saline:
1) Plasma Na
- No Change
2) ECF Volume:
- INCREASE
3) Urine Na:
- INCREASE
4) ICF Volume:
- No Change
5) ADH:
- No Change
Compensatory Mechanism
1) Osmoregulatory (ADH and Thirst)
- Sweating leads to Increased Thirst and ADH release to replace Water losses and lower plasma Na+ or Osmolarity
2) Volume Regulation (RAAS, ANP)
- Associated Volume repletion activates the SNS and RAAS to maintain GFR as well as lowering ANP release to limit further Na+ losses by INCREASED Tubular Na+ Reabsorption
