ABG's

Question 1

Assessment and Care of Patients with Acid-Base Imbalances

Answer 1

Question 2

What is pH

Answer 2

˜balance of acids and bases in body fluids

Question 3

What is the normal Arterial pH balance

Answer 3

7.35 to 7.45

Question 4

What is the normal Venous pH balance

Answer 4

7.31 to 7.41

Question 5

What is the normal pCO2

Answer 5

35-45 mmHg

Question 6

What is the normal HCO3

Answer 6

22-26 mEq/L

Question 7

What pH levels can be fatal

Answer 7

˜pH <6.9 or >7.8 usually fatal

Question 8

Respiratory system more sensitive to which imbalance

Answer 8

˜acid-base changes; can begin compensating in seconds to minutes

Question 9

Kidneys are more powerful in what?

Answer 9

result in rapid changes in ECF composition; fully triggered for imbalance of several hours to days

Question 10

What are the types of Acid-Base Imbalances

Answer 10

˜Metabolic acidosis
˜Respiratory acidosis
˜Metabolic alkalosis
˜Respiratory alkalosis

Question 11

Acid-Base Mnemonic—ROME

Answer 11

˜Respiratory

˜Opposite

Alkalosis ↑ pH ↓ PaCO2

Acidosis ↓ pH ↑ PaCO2

˜Metabolic

˜Equal

Acidosis ↓ pH ↓ HCO3

Alkalosis ↑ pH ↑ HCO3

Question 12

Laboratory Assessment:
Metabolic Acidosis

Answer 12

˜pH <7.35

˜Bicarbonate <21 mEq/L

˜Pao2 normal

˜Paco2 normal or slightly decreased

˜Serum potassium high

Question 13

Respiratory Acidosis

Answer 13

˜Respiratory function is impaired, causing problems with O2 and CO2

˜Retention of CO:

Respiratory depression

Inadequate chest expansion

Airway obstruction

Reduced alveolar-capillary diffusion

˜Hallmark of respiratory acidosis:

Decreased Pao2 with rising Paco2

Question 14

Laboratory Assessment:
Respiratory Acidosis

Answer 14

˜pH <7.35

˜Pao2 low

˜Paco2 high

˜Serum bicarbonate variable

˜Serum potassium levels elevated (if acute acidosis)

Serum potassium levels normal or low (if renal compensation present

Question 15

Acidosis: Patient-Centered Collaborative Care

Answer 15

˜History

˜CNS changes

˜Neuromuscular changes

↓ Muscle tone, deep tendon reflexes

˜Cardiovascular changes

Early: ↑ Heart rate, cardiac output changes

Worsening: Hyperkalemia; ↓ heart rate; T wave peaked and QRS widened; weak peripheral pulses; hypotension

˜Respiratory changes
Kussmaul respiration
˜Skin changes (metabolic and respiratory acidosis)
Warm, dry, and pink (vasodilation)
˜Psychosocial assessment

Question 16

Interventions: Metabolic Acidosis

Answer 16

˜Hydration

˜Drug therapy

Insulin to treat DKA

Antidiarrheals

Bicarbonate (only with low serum level)

Question 17

Interventions: Respiratory Acidosis

Answer 17

˜Focus is on improving ventilation and oxygenation, maintaining patent airway

˜Drug therapy

Bronchodilators

Anti-inflammatories

Mucolytics

˜Oxygen therapy

˜Pulmonary hygiene

˜Ventilation support

Prevention of complications

Question 18

Metabolic Alkalosis

Answer 18

˜Base excess – Excessive intake bicarbonates, carbonates, acetates, citrates

˜Acid deficit – Prolonged vomiting, excess cortisol, hyperaldosteronism, thiazide diuretics, prolonged NG suction

˜Hallmark of base excess acidosis:

ABG result with ↑ pH and ↑ bicarbonate level with normal O2 and CO2 levels

Question 19

Respiratory Alkalosis

Answer 19

˜Hyperventilation – Anxiety, fear, improper vent settings, stimulation of central respiratory center due to fever, CNS lesion, salicylates

˜Hallmark of respiratory alkalosis:

ABG result with ↑ pH coupled with low CO2 level

O2 and bicarbonate usually normal

Question 20

Alkalosis: Patient-Centered Collaborative Care

Answer 20

˜Assessment (same for metabolic and respiratory alkalosis)

˜Hypocalcemia

˜Hypokalemia

˜CNS changes – Positive Chvostek’s and Trousseau’s signs

˜Neuromuscular changes – Tetany-twitching of facial muscles

˜Cardiovascular changes

Respiratory changes

Question 21

Interventions: Alkalosis

Answer 21

˜Prevent further losses of hydrogen, potassium, calcium, chloride ions
˜Restore fluid balance
˜Monitor changes, provide safety
˜Modify or stop gastric suctioning, IV solutions with base, drugs that promote hydrogen ion excretion