Med Surg 1
Fluid, Electrolytes, and pH balance
hypotonic solution – fewer solutes than isotonic. (½ NS)
Isotonic solution – equal amount to the average bod fluids (NS)
hypertonic solution – more solutes than isotonic. (3%NS)
- HypOvolemia – Volume deficit
- causes: V/D, insensible, burns, 3rd spacing.
- increase: HR, RR. (compensating for the decrease in intravascular volume volume)
- Decrease: BP, UO, turgor of skin, and weight.
- restless, and lethargic
- HypERvolemia – Volume excess
- causes: HF, SIADH (too much ADH hormone), too much IV fluids
- Increase: HR, BP, Edema, weight, JVD
- crackles, confusion, HA (neuro s/s from the increased intracranial pressure)
- we are mostly concerned
osmolality of a “normal” person’s serum is 280-300 mOsm (NS is about 300)
- The higher the osmolality the more hypertonic the fluid is.
Factors affecting the fluid volume, and electrolytes:
- HF, N/V/D, fluid and food intake and output, chronic illness (renal, liver, Adrenal)
- Measure I/O’s!! avoid trying to catch up with fluid balance, stay on top of it before it gets out of control.
- recording I/O’s, and daily weights will allow us as nurses to manage the volume of fluid and correct issues. Avoid trying to catch up with IV fluid replacements
- 1 liter weighs 1 kilogram
- Confusion is an important sign when a person is out of homeostasis.
- OLD people are at high risk! especially if they are getting
- a person’s I is 1200ml and O is 3600 ml. The person is in a fluid volume deficit.
Trends are VERY important when looking at labs and s/s!! Also look at the patient and look for errors in the sampling when there is a result that does not make sense.
- Cations (+): K+(3.5-5), Na+(135-145), Ca+(8.6-10.2) Mg+ (1.5-2.5)
- Anions (-): Cl–, HCO3–, PO4⁻ (2.4-4.5)
- Extracellular Fluid: Na, Cl, and HCO3
- Intracellular fluid: K, Mg, and PO4
other normal lab levels
- WBC 5-10
- Hgb 15
- Hct 40% (about 3x the Hgb)
- Hyper – >145 (135-145)
- High concentration of the Na in the ECF pulls the fluid out of the cells causing cells to shrink
- Usually caused by dehydration
- can be caused by: diarrhea, hyperaldosteronism, DI, fluid restriction. (loss of fluid, or gain of Na)
- s/s: orthostatic hypotension, thirst, restlessness, agitated and disorientated, increase in tone of MM or fatigue. (FALL RISK)
- REhydrate the person with ½ NS slowly if dehydration is the problem. do this slowly so that the cells do not swell too much (brain cells swelling will cause change in LOC)
- HypO – <135 mEq
- Low concentration of Na outside the cells cause fluid to move into the cells where there is a higher concentration of Na causing the cells to swell.
- MOST common electrolyte balance issue seen in the hospital.
- caused by: N/V, suctioning, diarrhea, water enama, SIADH.
- s/s: Confusion, change in LOC, seizures, HA, decrease in tone or fatigue, cramping, Orthostatic hypotension, tachycardia.
- restrict water, replace Na, ADH antagonist,
Both low and high levels of Na will throw off a person’s LOC
The increased rate of change will increase the s/s
K + (3.5-5) low causes PVC (early beats), premature arrhythmias. high levels causes, bradycardia, asystole.
- HyperK > 5.0
- caused by: an infusion that was too quick, burns, tumor lysis, crushing injuries, renal injuries, adrenal insufficiency, DM that is poorly controlled.
- acidosis can increase K in the ECF, insulin will carry the K back into the cell.
- fix this with: stop K intake, Kayexalate, IV insulin with glucose. (sometimes albuterol will be ordered to decrease K as well, the albuterol will stimulate the release of insulin then the insulin will move the K into the cell)
- HypoK <3.5
- causes: suction, N/V/D, alkalosis, increased insulin
- s/s: irregular HR, fatigue, cramps, slow shallow respirations (to compensate if they are alkalotic)
- Give magnesium before potassium if IV
- monitor closely if the K dose is given then their output stops.
- Hypercalcemia (8.5-10.2)
- administer diuretics that excrete Ca
- causes: immobility, increased parathyroid hormone, increase calcium containing antacids
- decreased neuromuscular excitability, mm weakness, decreased clotting time
- causes: alkalosis, bone issues, decrease parathyroid hormone, malnutrition, blood transfusion
- chvostek’s sign(cheek twitch), trousseau’s (decorticate posture in hand and arm when a bp cuff is put on)
- hyperMagnesemia (>2.5 mEq/L)
- causes: increased intake,
- s/s: flaccid muscles, slow resp rate, weak muscles.
- HypoMag <1.5 mEq
- causes: D/V, ETOH abuse, nutritional issues, and suctioning.
- s/s: tetany, seizures, lethal dysrhythmias.
- replace the mag,
- phosphate (2.5-4.5)
- not as essential
- part of ATP
- causes: ETOH withdrawal, refeeding syndrome, DKA recovery
- s/s: weakness, rhabdomyolysis, confusion,
- causes: renal failure, chemo,
- s/s: lethargy, tetany, drowsiness,