Lab Values Flashcards
Sodium-Potassium pump
Sodium ions (Na+) are pumped OUT of the cell and potassium ions (K+) are pumped INTO the cell
*energy to drive the pump is released by hydrolysis of ATP
What is the main cation of ECF , what does it do
Sodium, plays a major role in maintaining the concentration and volume of ECF and influencing water distribution between ECF and ICF, important in generating and transmitting nerve impulses, muscle contractility, and regulating acid-base balance
What does serum sodium levels reflect
The ratio of sodium to water
(Not necessarily the amount of sodium in the body)
ECF osmolarity main determinant
Sodium
Hypertonic imbalance cause
Water to move from inside the cell into the ECF (to dilute the concentrated sodium) causing the cell to shrink
Hypotonic imbalance cause
Causes water to move into the cell, causing the cell to swell
How does sodium leave the body
Through urine, sweat, and feces
(Mainly regulated by the kidneys under the influence of ADH)
What is the most abundant extracellular cation
Sodium
What ere the functions of sodium
-primary determinant in ECF osmolality
-influences water distribution between ECF & ICF
-serum Na+ level reflects the ratio of Na+ to water
-role in maintaing BP
-transmission of nerve impulse and muscle contractility
-acid-base balance
Why should people with Hypertension not have too much salt
Too much salt will increase volume in the intracellular space
Osmolarity
A measurement concentration of molecule per weight of water
*concentration of solutes in the blood
Low soules=low sosmolarity
Low Na+ osmolarity = hypoosmolarity
(Solute concentration is what drives the movement of water)
Hypervolemic hyponatremia
Occurs when the body has an increase in total body water that’s greater than the increase in total body sodium. This causes a marked increase in extracellular fluid volume, which can lead to edema. Common causes include heart failure, cirrhosis, and kidney injury. Treatment includes correcting the underlying cause, restricting sodium and fluids, and using diuretics.
Hypovolemic hyponatremia
Occurs when the body has a decrease in total body water that’s greater than the decrease in total body sodium. This causes a decrease in extracellular fluid volume. Common causes include fluid losses from the kidneys or gastrointestinal tract, such as from diarrhea or overdiuresis. Treatment typically involves normal saline.
Both hypovolemic & hypervolemic hyponatremia are common in
Older adults d/t comorbidities
Multiple Rx
Lack of access to food/water
Lack of thirst
Na+ loss> total body water
Hypovolemic hyponatremia
Total body water gain> Na+
Hypervolemic hyponatremia
What are the causes of hypovolemic hyponatremia
Excessive sweating
Vommiting
Diahrrea
Diuretics
What are the causes of hypervolemic hyponatremia
Fluid volume overload
-kidney failure
-liver failure
-heart failure
(Edema common itch these chronic conditions)
What are the symptoms of hyponatremia
Stupor/coma
Anorexia
Lethargy
Tendon reflexes decrease
Limp muscles
Orthostatic hypotension
Seizures
Stomach cramping
(Headache, altered mental status, muscle weakness and cramps)
How does hyponatremia play a role in nerve impulses
Sodium must be available at normal levels in order to have normal conduction of nerve pulses, if these action potential slow down then symptoms will be present
Orthostatic hypotension
A form of low blood pressure that happens when standing up from sitting or lying down.
Can occur with hyponatremia
Ascites
Ascites is a condition that occurs when fluid collects in spaces in your belly (abdomen). If severe, it may be painful. The problem may keep you from moving around comfortably. Ascites can set the stage for an infection in your abdomen. Fluid may also move into your chest and surround your lungs.
Hyponatremia can cause ascites because
retention of sodium and water to compensate for the low effective circulatory volume resulting in the development of ascites.
(Lack of volume in the ECF, fluid moves out and into the intravascular space which is not functional)
Hypovolemic hyponatremia interventions
With hold diuretics
Replace sodium & water
Isotonic IV therapy
Hypervolemic hyponatremia interventions
Fluid restriction (may have edema)
Tx of underlying disorder (HF, renal, hepatic)
What are the nursing implications for hyponatremia
Neurological assessment
Implement seizure precautions (if severe)
Implement fall precautions
Monitor intake and output
Daily weights if edema present