Acid-Base Balance Flashcards
substance that releases hydrogen ions (H+)
Acid
have a low hydrogen ion concentration and can accept hydrogen ions in solution.
Bases (Alkalis)
the relative acidity or alkalinity of a solution
pH
reflects the hydrogen ion concentration of the solution (inversely proportional)
pH
normal pH
7.35-7.45
prevent excessive changes in pH by removing or releasing hydrogen ions
buffers
Major buffer systems in the ECF:
- Bicarbonate (HCO3-)
- Carbonic acid (H2CO3)
acid buffer; opponent of acids
Bicarbonate (HCO3-)
weak acid
Carbonic acid (H2CO3)
TO ACHIEVE NORMAL pH
1 part Carbonic Acid (1.2 mEq/L) : 20 parts bicarbonate (24
mEq/L)
adding a strong acid in the ECF, depleting the bicarbonate and lowering the pH levels
ACIDOSIS
adding a strong base to the ECF, depleting carbonic acid as it combines with the base, increasing the pH levels.
ALKALOSIS
The lungs help regulate acid-base balance by eliminating or retaining Carbon Dioxide (CO2), a potential acid
RESPIRATORY REGULATION
Carbon Dioxide (CO2) + Water (H2O) =
Carbonic acid (H2CO3)
The lungs help regulate acid-base balance by ________________________________, a potential acid.
eliminating or retaining Carbon Dioxide (CO2)
respiration rate and depth increases, exhaling CO2 and decreasing carbonic acid levels
High Carbonic acid (H2CO3) and CO2 levels
the respiration rate and dept are reduced, retaining CO2 and increasing carbonic acid levels
High Bicarbonate (HCO3-) levels
are the ultimate long-term regulator of acidbase balance, although slower to respond to changes
Kidneys
regulate pH by reabsorbing and regenerating bicarbonate and hydrogen ions
Kidneys
Hydrogen ion (H+) + Bicarbonate (HCO3-) =
Carbonic acid (H2CO3)
kidneys reabsorb and regenerate bicarbonate and excrete hydrogen ions ○ H2CO3»_space; H+ (excreted) and HCO3- (retained)
High H+ ions (acidic)
excess bicarbonate is excreted and H+ ion is retained ○ H2CO3»_space; H+ (retained) and HCO3- (excreted)
Low H+ ions (alkalosis)
FACTORS AFFECTING BODY FLUID, ELECTROLYTES, AND ACID-BASE BALANCE:
◎ Age
◎ Gender and Body Size
◎ Environmental Temperature
◎ Lifestyle
Two basic types of Fluid Imbalances
Isotonic and Osmolar
water and electrolytes are lost or gained in equal proportions
Isotonic
loss or gain of only water, so that the osmolality of the serum is altered (electrolytes are concentrated)
Osmolar
Four Categories of Fluid Imbalances
◎ Fluid Volume Deficit
◎ Fluid Volume Excess
◎ Dehydration (hyperosmolar imbalance)
◎ Overhydration (hypo-osmolar imbalance)
The body loses both water and electrolytes from the ECF (intravascular compartment) in similar proportions
Fluid Volume Deficit (FVD)
The body loses both water and electrolytes from the ECF (intravascular compartment) in similar proportions, so it often is called ______________________
hypovolemia
Causes of Fluid Volume Deficit (FV):
○ Abnormal losses through the skin, GI tract, kidney
○ Movement of fluid in a third space (area that deems the fluid unavailable for us)
The body retains both water and sodium in similar proportions to normal ECF
Fluid Volume Excess (FVE)
The body retains both water and sodium in similar proportions to normal ECF, often called ___________________________
hypervolemia
Causes of Fluid Volume Excess (FVE):
○ Increased intake of NaCl (sodium level is still normal, since both water and sodium are equally retained)
○ Infusion of sodium-containing fluids rapidly
○ Disease processes (heart failure, kidney failure, liver cirrhosis)
excess interstitial fluid
Edema
leaves a small depression or pit after finger pressure is applied
Pitting Edema
Water is lost from the body, leaving the client with excess sodium
Dehydration (Hyperosmolar imbalance)
Sodium levels are increased
Dehydration (Hyperosmolar imbalance)
Cells are dehydrated/shrunk
Dehydration (Hyperosmolar imbalance)
Causes of Dehydration (Hyperosmolar imbalance)
○ Diabetic Ketoacidosis (DKA)
○ Osmotic diuresis
○ Administration of hypertonic solutions
Water is gained in excess of electrolytes, resulting in low serum osmolality and low serum Na+ levels
Overhydration (hypo-osmolar imbalance)
Cells are swollen
Overhydration (hypo-osmolar imbalance)
Can lead to cerebral edema and impaired neurologic function
Overhydration (hypo-osmolar imbalance)
Causes of Overhydration (hypo-osmolar imbalance)
○ Syndrome of Inappropriate Anti-Diuretic Hormone (SIADH)
○ Head Injury
ELECTROLYTE IMBALANCES: SODIUM
Hyponatremia
Hypernatremia
- Less than 135 mEq/L
- Severe cases: <110 mEq/L
- Can lead to neurological damage (cerebral edema) due to low serum osmolality
- Causes: burns, GI losses, diuretics, head injury
Hyponatremia
- Higher than 145 mEq/L
- Cells are dehydrated
- Primary manifestations are neurological in nature
- Causes: water deprivation, diabetes insipidus, excessive use of NaCl
Hypernatremia
ELECTROLYTE IMBALANCES: POTASSIUM
Hypokalemia and Hyperkalemia
- Less than 3.5 mEq/L
- Causes:
GI losses (vomiting, diarrhea)
Potassium-wasting diuretics
Poor intake of Potassium - S/Sx: muscle weakness, lethargy, cardiac dysrhythmias
Hypokalemia
- More than 4.5 mEq/L
- More dangerous than hypokalemia – can lead to cardiac arrest
- Causes:
1. Renal Failure
2. High Potassium Intake
3. Burns - S/Sx: confusion, muscle weakness, bradycardia, irregular pulse, numbness in extremities
Hyperkalemia
ELECTROLYTE IMBALANCES: CALCIUM
Hypocalcemia and Hypercalcemia
- Total calcium: >10.5 mg/dL
- Ionized calcium: >5 mg/dL
Calcium is mobilized from the skeleton due to malignancy or prolonged immobilization
S/Sx: depressed DTR, cardiac dysrhythmias, hypercalciuria, flank pain secondary to urinary calculi
Hypercalcemia
- Total calcium: <8.5 mg/dL
- Ionized calcium: <4 mg/dL
- SEVERE HYPOCALCEMIA CAN CAUSE TETANY WITH MUSCLE SPASMS AND PARESTHESIAS AND CAN LEAD TO CONVULSIONS. Other manifestations include: decreased cardiac output, hyperactive DTR
- Two signs:
- Chvostek’s sign
- Trousseau’s sign
Causes: total thyroidectomy, hypomagnesemia, chronic alcoholism
Hypocalcemia
ELECTROLYTE IMBALANCES: MAGNESIUM
Hypomagnesemia and Hypermagnesemia
- More than 2.5 mEq/L
- Often iatrogenic (result of overzealous magnesium therapy)
- S/Sx: depressed DTR, bradycardia, lethargy, respiratory depression, cardiac arrest
Hypermagnesemia
- Less than 1.5 mEq/L
- Common cause: chronic alcoholism
- Other causes: GI losses, burns, pancreatitis
- S/Sx: Chvostek’s and Trousseau, increased reflexes,
respiratory difficulties, cardiac dysrhythmias
Hypomagnesemia
ELECTROLYTE IMBALANCES: CHLORIDE
Hypochloremia and Hyperchloremia
- Below 95 mEq/L
- Causes: GI/kidney losses, sweating
- S/Sx: muscle twitching, tremors, tetany
Hypochloremia
- Above 108 mEq/L
- Causes: excess replacement of NaCl or KCl
- S/Sx: acidosis, weakness, lethargy, dysrhythmias, coma
Hyperchloremia
ELECTROLYTE IMBALANCES: PHOSPHATE
Hypophosphatemia and Hyperphosphatemia
- Below 2.5 mg/dL
- Causes: GI losses, use of phosphate-binding antacids, alcohol withdrawal
- S/Sx: paresthesias, muscle weakness and pain, metal
changes, and possible seizures
Hypophosphatemia
- Above 4.5 mg/dL
- Causes: tissue trauma, chemotherapy, renal failure, increased ingestion/administration of phosphate
- S/Sx: numbness, tingling around the mouth and
fingertips, muscle spasms, tetany
- S/Sx: numbness, tingling around the mouth and
Hyperphosphatemia
Acid-base imbalances
◎ Classified as:
respiratory or metabolic
are normally regulated by the lungs through the retention/excretion of CO2 (respiratory acidosis or alkalosis)
Carbonic acid levels
Carbonic acid levels are normally regulated by the ____________ through the retention/excretion of CO2 (respiratory acidosis or alkalosis)
lungs
________________________________________ are regulated by
the kidneys (metabolic acidosis or alkalosis)
Bicarbonate and Hydrogen ion levels
Bicarbonate and Hydrogen ion levels are regulated by
the _____________ (metabolic acidosis or alkalosis)
kidneys
Hypoventilation and CO2 retention cause carbonic acid
to increase and the pH to fall below 7.35
RESPIRATORY ACIDOSIS
This causes the kidneys to retain bicarbonate to restore the normal carbonic acid to bicarbonate ratio
RESPIRATORY ACIDOSIS
When a person hyperventilates, exhaling more CO2 and decreasing carbonic acid levels = pH greater than 7.45
RESPIRATORY ALKALOSIS
Kidneys will excrete bicarbonate
RESPIRATORY ALKALOSIS
When bicarbonate levels are low in relation to the amount of carbonic acid = decreased pH
METABOLIC ACIDOSIS
Stimulates the respiratory center = increase depth and rate of respirations; CO2 is eliminated and carbonic acid falls
METABOLIC ACIDOSIS
The amount of bicarbonate in the body exceeds to the normal ratio
METABOLIC ALKALOSIS
Depresses the respiratory rate (slow and shallow) = CO2 is
retained and carbonic levels increases
METABOLIC ALKALOSIS
Types of Intravenous Fluids:
Hypertonic solution
Hypotonic solution
Isotonic solution
concentrated with solute, expanding vascular volume
Hypertonic solution
less solutes, for treatment of cellular dehydration
Hypotonic solution
Enteral Fluid and Electrolyte Replacement
- Fluid intake modifications
- Dietary changes
- Oral electrolyte supplements
Sodium Chloride
Normal Saline
Ringer’s solution
Sodium, chloride, potassium, calcium
Lactated Ringer’s solution
Sodium, chloride, potassium, calcium, and lactate
metabolized in the liver to form bicarbonate
lactate
– dextran, plasma, albumin
- used for severe blood/plasma loss
Volume expanders
hourly rate of the fluid
Milliliters per hour (cc/hr)
cc/hr =
total infusion volume/total infusion time
Drops per minute
gtts/min
gtts/min
total infusion volume x drop factor/total time of infusion in minutes
number of drops delivered per mL of solution (gtts/mL)
Drop factor
commonly used for intermittent or continuous infusions
Metacarpal, basilic and cephalic veins
inserted in the subclavian or jugular vein, with the distal tip
resting in the SVC.
Central Venous Catheters
complications of Central Venous Catheters:
hemothorax/pneumothorax, cardiac perforation, thrombosis, infection
inserted in basilic or cephalic vein, for long -term intravenous access when the client will be maintaining IV
therapy at home
Peripherally Inserted Central Venous Catheter (PICC)
Can be effective in restoring intravascular (blood) volume
BLOOD TRANSFUSIONS
Four main groups/types of human blood:
A, AB, B, O
Rhesus (Rh) Factor:
Rh+ or Rh-
is the only IV solution that is compatible with blood products
0.9% NaCl (Plain NSS)
not commonly used except for extreme cases of acute hemorrhage; RBCs, plasma, plasma proteins, fresh platelets, and other clotting factors
Whole Blood
increase the oxygencarrying capacity of blood in anemia, surgery and blood disorders
Packed Red Blood Cells (RBCs)
bleeding disorders or platelet deficiency
Platelets
expands blood volume and provides clotting factors. No need to be typed and crossmatched
Fresh Frozen Plasma (FFP)
blood volume expander
Albumin and Plasma Protein Fraction
Blood Products
Whole Blood
Packed Red Blood Cells (RBCs)
Platelets
Fresh Frozen Plasma (FFP)
Albumin and Plasma Protein Fraction