BP control (neuro-hormonal regulation)
- baroreceptors reflex & sympathetic NS
- RAAS (⇡ BP by ⇡BV, ⇡ vasoconstriction)
- ADH = vasopressin (⇡ BP by ⇡BV, ⇡ vasoconstriction)
- kidneys - long term control of BP thru regulating BV
osmolality
- pulling power of a solution for H2O
- determined by concentration of solutes
which organ has the thirst mechanism?
hypothalamus
ADH = vasopressin
- released by pituitary gland
- function:
1. regulate fluid balance by retaining H20
2. concentrate or dilute urine from collecting ducts
3. vasoconstriction - constrict arteriole smooth muscle
Diabetes (meaning)
large amount of urination
- mellitus - sweet (↓ insulin production)
- insipidus - tastes like water (↓ ADH production)
↓ of ADH (diabetes insipidus)
- ⇡loss of urine –> diluted urine - dehydration
- s/sx = cells shrink – change in mental status
Lab? - hypernatremia
Rx = DDAVP (replace ADH) - fluid replacement, monitor I&O, weight
⇡of ADH (SIADH - syndrome of inappropriate ADH)
- ↓ loss of urine –> concentrated urine - retain H20
- s/sx = cells swell = change in mental status
Rx - Na+ replacement - fluid restriction, weight
Fluid Volume Excess (FVE)
Proportionate ⇡of H20 & Na+
Fluid overload, overhydration, pulmonary edema (drowning), hypervolemia (too much volume in blood), pitting edema
Caused by: HF, CKD, cirrhosis, malnutrition
NI: fluid restriction, Na+ intake, diuretic
Monitor: I/Os, daily wt, TED stockings
Edema
too much fluid w/in interstitial
- pulmonary edema = in lungs/alveoli
- pleural effusion = in pleural space
- ascites = fluid in peritoneal cavity
- periphery = pitting edema
Causes: HF, cirrhosis, renal failure, malnutrition
Rx: diuretic, TED stockings, elevate legs, SCD
Fluid Volume Deficit (FVD)
- dehydration, hypovolemia
- if not treated, can go into hypovolemic shock
causes: proportionate ↓ of Na+ & H20
Rx: anti-diuretic
Labs: keep eye out for hypokalemia (affects heart)
S/Sx of FVD
- flat jugular vein
- change in mental status
- ⇡ pulse, but thready; ↓ BP
- dry mouth, constipation
- tenting of skin; wt loss
Rx: give fluids
isotonic fluids
0.9% normal saline (NS) lactated ringers (LR) - contain Na+, Cl-, K+, Ca++
hypotonic IV solutions
- D5W
- 0.45% NS
hypertonic IV solutions
- 3% NS
- dangerous
Na+ balance
135 - 145 mEq/L
hyponatremia - Na+ level?
Na+
hypernatremia - Na+ level?
> 145 mEq/L
Causes: ↓ in H20 intake – defect in thirst mechanism; if unconscious - unable to drink; dehydration
S/Sx: cells shrink, change in mental status, muscle twitching
Rx: Na+ restriction, IV hypotonic (0.45% NS or D5W)
Normal Potassium (K+) levels?
3.5 - 5.0 mEq/L
↓ or ⇡ will affect heart rhythm
essential for transmission & conduction of nerve impulses & muscle contraction
hypokalemia - levels?
K+
hyperkalemia - levels?
K+> 5.0 mEq/L
Causes: renal failure; movement of K+ from ICF to ECF as result of burn injury, crash injury
S/Sx - change in EKG, muscle weakness
Rx: kayexalate sorbital – binds to K+ in GI tract & excreted in stool (K+ & glucose move together); dialysis if in renal failure.
Oncotic pressure
Pressure caused by protein
Pulls H20 into space
Hydrostatic pressure
Pressure of blood pushing through veins pushes H20 out.
BMP
Basic metabolic panel
Checks electrolyte balance
Calcium levels - normal
8.5 - 10.5 mg/dL
