Exam 1 (Fluids, Electrolytes, Acid-Base) Flashcards
Normal range for K+
3.5-5.0 mEq/L
Na+ normal range
136-145 mEq/L
Normal range for Ca++
8.8-10.5 mg/dL
Normal range of Mg+
1.3-2.1 mEq/L
Normal range for Cl-
95-105 mEq/L
Normal range for phosphate (mostly HPO4-)
3.0-4.5 mg/L
Normal range for pH
7.35-7.45
Normal range for CO2
35-44 mm Hg
Normal range for O2
80-100 mm Hg
Normal range for bicarbonate (HCO3)?
21-28 mEq/L
Osmolality
The concentration of a solution in terms of osmoles of solutes per kilogram of solvent.
High osmolality means that there is less water than solute - WATER DEFICIT
Low osmolality means that there is more water than solute - WATER EXCESS
Osmolarity
The concentration of a solution n terms of osmoles or milliosmoles of solutes per liter of solution. (The solutes, or solid particles, are electrolytes such as sodium.)
Isotonic
Having the same concentration of solute as another solution – this means each solution has the same oncotic pressure.
Having equal tension
Hypotonic
Having a smaller concentration of solute than another solution
The solution having the smaller concentration exerts less oncotic pressure than the solution with greater concentration of solutes.
Hypertonic
Having a greater concentration of solute than another solution
The solution having the greater concentration exerts more oncotic pressure than the solution with smaller concentration of solutes
Colloid osmotic pressure
Colloids are particles with large molecular weights
The colloids are too large to move across the membrane
Plasma colloid osmotic pressure is the osmotic pressure exerted by these proteins
Tissue hydrostatic pressure
The pressure exerted on the interstitial fluid by the elastic recoil of the tissues in any region of the body
This force tends to push water from the interstitial fluid back into the capillaries
High/low osmolarity causes:
High osmolarity causes:
- Thirst -> increased water intake
- ADH release -> water reabsorbed from urine
Low osmolarity causes:
- Lack of thirst -> decreased water intake
- Decreased ADH release -> water lost in urine
True/False
Increased levels of ADH decrease urine output
True
ADH prevents diuresis by causing more water to be absorbed in the kidney tubules. If more water is absorbed, there is less water left to eliminate as waste, decreasing urine output.
Clinical manifestations r/t ADH elevation
Mild central nervous system dysfunction: malaise, anorexia, nausea, vomiting, headache
Severe central nervous system dysfunction: confusion, lethargy, seizures, coma, fatal cerebral herniation
Comparison of ADH & Aldosterone
- ADH is the “tap water” hormone - causes kidneys to reabsorb water; renal absorption of water due to ADH makes a smaller volume of more concentrated urine
- Aldosterone is the “saltwater” hormone - causes kidneys to reabsorb sodium and water; renal reabsorption of sodium and water due to aldosterone makes a smaller volume of urine
Hypovolemia Clinical Manifestations (S/S)
_ Sudden weight loss
_ Postural blood pressure decrease with concurrent increased heart rate
- Flat neck veins when a patient is supine
- Prolonged small vein filling time
- Prolonged capillary refill time
- Lightheadedness
- Dizziness
- Syncope
- Oliguria or small volume of concentrated urine
- Decreased skin turgor
- Dryness of oral mucous membranes btwn cheek & gum
- Hard stools
- Soft sunken eyeballs
- Longitudinal furrows in the tongue
- Absence of tears & sweat
- In infants, fontanel may be sunken; neck veins not reliably assessed in infants
Types of abnormal fluid loss
- Emesis (vomiting)
- Tubes in the GI tract or other body cavities
- Hemorrhage
- Drainage from fistulas, wounds, or open skin
- Paracentesis
The nurse is caring for a client with congestive heart failure. On assessment, the nurse notes that the client is dyspneic and that crackles are audible on auscultation. The nurse suspects excess fluid volume. What additional signs would the nurse expect to note in this client if excess fluid volume is present?
- Weight loss
- Flat neck and hand veins
- An increase in blood pressure
- A decreased central venous pressure (CVP)
- An increase in blood pressure
A fluid volume excess is also known as overhydration or fluid overload and occurs when fluid intake or fluid retention exceeds the fluid needs of the body. Assessment findings associated with fluid volume excess include cough, dyspmnea, crackles, tachypnea, tachycardia, elevated blood pressure, bounding pulse, elevated CVP, weight gain, edema, neck and hand vein distention, altered level of consciousness, and decreased hematocrit.
A nurse is preparing to care for a client with a potassium deficit. The nurse reviews the client’s record and determines that the client was at risk for developing the potassium deficit because the client:
- Sustained tissue damage
- Requires nasogastric suction
- Has a history of Addison’s disease
- Is taking a potassium-sparing diuretic
- Requires nasogastric suction
The normal serum potassium level is 3.5 mEq/L to 5.1 mEq/L. A potassium deficit is known as hypokalemia. Potassium-rich gastrointestinal fluids are lost through gastrointestinal suction, placing the client
The nurse would identify which set of blood gas values as consistent with a diagnosis of respiratory acidosis in a client?
- pH 7.0; PaCO2 42, HCO3- 24
- pH 7.46; PaCO2 38, HCO3- 22
- pH 7.35; PaCO2 44, HCO3- 26
- pH 7.32; PaCO2 48, HCO3- 25
- 4
The nurse would expect to see a decreased pH and increased PaCO2 in a client with respiratory acidosis (pH 7.32; PaCO2 48, HCO3- 25). Normal pH is 7.35 to 7.45, and normal PaCO2 is 35 to 45 mm Hg. This series of values (pH 7.0; PaCO2 42, HCO3- 24) indicates a very low pH, which is moving into the range of incompatibility f with life. This series of values (pH 7.46; PaCO2 38, HCO3- 22) is mostly within normal range with just a slight elevation in the pH. This series of values (pH 7.35; PaCO2 44, HCO3- 26) are within the normal range.
An older adult client is experiencing difficulty with edema and fluid overload. What nursing intervention would be the most accurate in evaluating the client’s fluid balance?
- Measure the intake and output
- Check for thirst and skin turgor
- Evaluate changes in daily weight
- Evaluate vital signs every 3 hours
- 3
The priority assessment for a client with fluid problems is to obtain the daily weight. Weight gain and loss are the most accurate measurements of fluid gain and loss. Checking tissue turgor on an older adult is not very accurate since many older adults have poor turgor. Thirst is too nonspecific. The I&O is important, but it is not as accurate in evaluating the amount of fluid retained as is the daily weight.
