Concept D: Arterial Blood Gasses/f & E

Front 1

Consist of molecules that can give up, or donate, H+ ions to other molecules:

Back 1

-Acids (Carbonic Acid)

Front 2

Consist of molecules that can accept, H+ ions:

Back 2

-Bases (Bicarbonate)

Front 3

When pH rises or falls, 3 regulatory systems come into play, name those:

Back 3

1.) Chemical Buffers
2.) Respiratory System
3.) Renal System

Front 4

-Body maintains a healthy pH in part through these
-Substances that minimize changes in pH by combining with excess acids or bases
-Found in blood, intracellular fluid, and interstitial fluid

Back 4

-Chemical Buffers (HCO3, PO4, and protein)

Front 5

What is the body's primary buffer and what is it responsible for?

Back 5

-HCO3

-Buffering blood and interstitial fluid by relying on series of chemical reactions in which pairs of weak acids and bases (such carbonic acid and HCO3) combine with stronger acids (such as HCL) and bases to weaken them

Front 6

How does phosphate help alter pH in the body?

Back 6

-React with either acids or bases to form compounds that slightly alter pH (most often in the renal tubules)

Front 7

How do protein buffers help alter pH in the body?

Back 7

-Work inside and outside cells
-Bind with acids and bases to neutralize them

Front 8

This second line of defense regulates blood levels of CO2, which combines with H20 to form carbonic acid:

Back 8

-Respiratory system

Front 9

How do the lungs help to alter pH in the body?

Back 9

-Chemoreceptors in the medulla senses pH changes and vary the rate and depth of respirations to compensate
-Breathing faster or deeper eliminates more CO2 and breathing slower or less deeply retains CO2
-Lungs can handle twice the amount of acids and bases and can respond within minutes, but can restore normal pH only temporarily

Front 10

How do the kidneys help alter pH in the body?

Back 10

-Reabsorb acids and bases or excrete them into urine
-Produce HCO3 to replenish lost supplies
-Takes hours to days to complete
-Effectiveness changes with age
-If pH is <7.35, kidneys reabsorb HCO3 and also excrete H+ ions along with phosphate or ammonia
-If pH is >7.45, kidneys excrete HCO3 and retain more H+ ions

Front 11

If the body compensates only partially for an imbalance, pH.....

Back 11

-remains outside the normal range

Front 12

If the body compensates fully or completely, pH.....

Back 12

-returns to normal

Front 13

What does the anion gap help in determining a diagnosis?

Back 13

-Helps you differentiate among various acidotic conditions
-Refers to the relationship among the body's cations and anions
-Represents the level of unmeasured anions in ECF

Front 14

What does an increase in the anion gap determine?

Back 14

-Indicates an increase in the percentage of one or more unmeasured anions in the bloodstream
-Can occur with acidotic conditions characterized by higher-than-normal amounts of organic acids (lactic acidosis and ketoacidosis)

Front 15

What does a decrease in the anion gap determine?

Back 15

-Rare by may occur with hypermagnesemia and paraprotein enemia states

Front 16

What is the normal range for anion gap?

Back 16

-8 to 14 mEq/L

Front 17

The following conditions may lead to the development of which acid-base imbalance:
-Neuromuscular conditions: hypoventilation,
-Depression of the respiratory center in the brain: obesity, brain lesions
-Certain drugs: anesthetics, sedatives, opioids, hypnotics
-Lung Dz: respiratory infx, COPD, acute asthmatic episodes, chronic bronchitis, late stages of adult respiratory distress syndrome, pulmonary edema
-Chest wall trauma: flail chest, pneumothorax
-Airway obstruction: secretions, foreign bodies, tumors, anaphylaxis

Back 17

-Respiratory Acidosis

Front 18

Describe s&s of patient experiencing respiratory acidosis:

Back 18

-Altered LOC (restlessness, confusion, even coma)
-Depressed deep tendon reflexes
-N & V
-Headache from CO2
-Skin warm and flushed
-Rapid, shallow respirations (trying to breathe off CO2)
-Tachycardia
-Cyanosis (late)

Front 19

What F & E imbalance can occur with respiratory acidosis?

Back 19

-Hyperkalemia (overwhelming amount of H+ ions enter cells, causing K+ to leave the cell and enter bloodstream)

Front 20

Describe treatment for a patient experiencing respiratory acidosis:

Back 20

-Focus on improving ventilation and lowering PaCO2
-If respiratory is cause: bronchodilator, supplemental O2, drug therapy to treat hyperkalemia, antibiotic for infx, removal of secretions, removal of foreign body

Front 21

Describe nursing interventions for a patient experiencing respiratory acidosis:

Back 21

-Monitor VS and cardiac rhythm
-Continue to assess respiratory patterns and report changes quickly
-Monitor neurological status
-Report variations in ABG levels, pulse ox, or serum electrolytes
-Give meds as prescribed
-Admin O2 as ordered (keep in mind, patients with COPD require lower concentrations)
-Perform tracheal suctioning
-Monitor I & O

Front 22

The following conditions may lead to the development which aced-base imbalance:
-Any condition that causes a person to "blow off" CO2
-Hyperventilation
-CPR
-Pain
-Salicylate intoxication and can occur with use of nicotine, xanthines
-Hypermetabolic states: fever, liver failure, sepsis
-Conditions that affect the respiratory control center: higher progesterone levels during pregnancy, stroke, trauma
-Acute hypoxia: high altitude, pulmonary dz, severe anemia, pulmonary embolus, or hypotension
-Overventilation during mechanical ventilation

Back 22

-Respiratory Alkalosis

Front 23

What F & E imbalance is caused by respiratory alkalosis?

Back 23

-Hypokalemia: in defense against the rising pH, H+ ions are pulled out of the cells and into the blood in exchange for K+ ions
-Decreased ionized serum calcium levels: severe alkalosis inhibits calcium ionization

Front 24

Describe s&s for a patient experiencing respiratory alkalosis:

Back 24

-Increase rate and depth of respirations
-Tachycardia
-Anxious and restlessness
-Lightheadedness, muscle weakness, or difficulty breathing
-Tingling in fingers and toes (severe cases)
-ECG changes
-Hyperreflexia (due to lowered calcium levels)

Front 25

Describe treatment for a patient experiencing respiratory alkalosis:

Back 25

-Treating underlying disorder, including removing the causative agent: discontinuing a drug or treating a fever/sepsis
-If acute hypoxemia is cause, O2 therapy
-If anxiety is cause, patient may need sedative
-Counteract hyperventilation by breathing into the bag to force patient to breathe in CO2
-Mechanical ventilator may need to be adjusted

Front 26

Describe nursing interventions for a patient experiencing respiratory alkalosis:

Back 26

-Allay anxiety whenever possible to prevent hyperventilation
-Monitor VS
-Monitor ABG and serum electrolyte levels
-Check ventilator settings frequently
-Breathe into paper bag

Front 27

If a patient's anion gap is greater than 14 mEq/L, then the acidosis is a result of.....

Back 27

-an accumulation of metabolic acids

Front 28

If metabolic acidosis is associated with normal anion gap, then the acidosis is a result of....

Back 28

-loss of HCO3 may be the cause

Front 29

The following conditions may lead to which of the common acid-base imbalances:
-DM
-Chronic alcoholism
-Severe malnutrition or starvation
-Poor dietary intake of carbs
-Hyperthyroidism
-Severe infx with fever
-Lactic acidosis secondary from shock, HF, pulmonary dz, hepatic disorders, seizures, or strenuous exercise
-Renal insufficiency or renal failure (decreased ability of the kidneys to excrete acids)
-Excessive GI losses from diarrhea, intestinal malabsorption, a draining fistula of the pancreas or liver
-K-sparing diuretics
-Poisoning

Back 29

-Metabolic Acidosis

Front 30

What common acid-base imbalance can occur with metabolic acidosis?

Back 30

-Hyperkalemia
-Excess H+ alter the normal balance of K, Na, and Ca leading to reduced excitability of nerve cells

Front 31

Describe s&s for a patient experiencing metabolic acidosis:

Back 31

-Hyperventilation,especially Kussmaul's respirations
-Cardiac output decreased
-Arrhythmias
-At first, skin is warm & dry then becomes cold and clammy
-Muscle weakness
-Dull headache
-Altered LOC
-Diminished DTR
-Anorexia
-N & V
-Signs of hyperkalemia: abdominal cramping, diarrhea, muscle weakness, ECG changes

Front 32

Describe treatment for a patient experiencing metabolic acidosis:

Back 32

-Address both the symptoms and the underlying cause
-For pts with DKA: admin rapid-acting insulin and monitor serum K levels
-For pts with HCO3 loss: admin IV NaHCO3 to neutralize blood
-For pts with renal failure or toxic reaction to a drug: dialysis
-Ventilatory support

Front 33

Describe nursing interventions for a patient with metabolic acidosis:

Back 33

-If your patient already has metabolic acidosis, nursing care include immediate emergency interventions and long-term treatment of the condition and its underlying causes
-Monitor VS and cardiac rhythm
-Closely monitor LOC
-Maintain patent IV access
-Admin NaHCO3 as ordered (flush line with NS before and after)
-Position patient to promote chest expansion
-Monitor renal function
-Monitor serum electrolyte & ABG levels

Front 34

The following conditions may lead to which of the common acid-base imbalances:
-Hypokalemia (common) from the use of thiazides, furosemide, and other diuretics
-Hypocalcemia
-Hypochloremia
-Excessive acid loss from the GI tract (Vomiting-most common)
-Prolonged NG suctioning
-Diuretic therapy: can lead to a loss of H+, K+, and Cl- from the kidneys
-Cushing's dz
-Rebound alkalosis
-Posthypercapnic alkalosis
-Kidney dz
-Corticosteroids and antacids

Back 34

-Metabolic Alkalosis

Front 35

Describe s&s for a patient experiencing metabolic alkalosis:

Back 35

-Typically s&s are a result of hypokalemia so therefore, they are s&s of hypokalemia:
-slow, shallow respirations
-Neuromuscular excitability: muscle twitching; weakness; tetany; numbness and tingling of the fingers, toes, and mouth area
-Neurological: apathy, confusion, seizures, stupor, coma
-If hypokalemia affects the GI tract: anorexia, N & V
-If hypokalemia affects the GU tract: polyuria

Front 36

Describe treatment for a patient experiencing metabolic alkalosis:

Back 36

-Treatment aims to correct the acid-base imbalance by providing the patient's body sufficient time to rid itself of excess HCO3 and increase its H+ concentration:
-IV admin of ammonium chloride (rarely done but sometimes necessary)
-D/C of thiazide diuretics and NG suctioning
-Admin of an antiemetic
-Addition of acetazolamide to inhibit Ca and increase renal excretion of HCO3

Front 37

Describe nursing interventions for a patient experiencing metabolic alkalosis:

Back 37

-Monitor VS
-Assess patient's LOC
-Admin O2 as ordered to treat hypoxemia
-Admin diluted K+
-Monitor I & O
-Irrigate an NG tube with NS solution instead of tap water to avoid gastric electrolyte losses
-Assess ABG and electrolyte levels closely