Acid Base Disorders

Question 1

Normal Human Body pH

Answer 1

7.4

Question 2

How to get ABG

Answer 2

Draw blood from artery

Question 3

Three main systems of compensation
- Instant

Answer 3

1. Physiologic Buffers (rapid)
   - Carbonic Buffer System (also phosphate and protein buffers)

Question 4

Three main systems of compensation
- Fast

Answer 4

2. Lungs (minutes/hours)
   - Decrease CO2 = Increase Respiratory Rate = More Basic
   - Increase CO2 = Decrease Respiratory Rate = More Acidic

Question 5

Three main systems of compensation
- Slow

Answer 5

3. Kidneys (metabolic, more than 2 days)
   - Increase HCO3 = reabsorb or produce HCO3 = More basic

• Decrease HCO3 = excrete HCO3
  = More acidic

Question 6

Primary Respiratory Alkalosis
- Symptoms

Answer 6

CNS Effects
Mild: Dizziness, Lightheadedness, paresthesia

Severe: Confusion, Seizure

Question 7

Primary Respiratory Alkalosis
- Causes

Answer 7

Hyperventilation
- Drug Induced (Nicotine)
- Anxiety
- Infection

Hypoxia
- High altitude

Question 8

Primary Respiratory Acidosis
- Symptoms

Answer 8

Headache, delirium, coma

Tachycardia, Arrhythmia

Hypotensive Symptoms (Dizziness, lightheaded)

Question 9

Primary Respiratory Acidosis
- Causes

Answer 9

Hypoventilation
- Drug induced
- Neuromuscular dysfunction
- Head injury

Airway obstruction
- Pneumonia
- COPD
- Pulmonary Edema

Hypermetabolic Stress
- Too much metabolism leading to accumulation of CO2

Question 10

Primary Metabolic Alkalosis
- Symptoms

Answer 10

CNS Effects
- Lethargy, confusion
- Muscle weakness
- Hypoventilation
- Hypokalemia
- Cardiac Effects

Question 11

Primary Respiratory Alkalosis
- Causes

Answer 11

Intake of excess alkali

Severely decreased renal function

Loss of excess hydrogen ions (Vomiting diuretics)

Question 12

Primary Metabolic Acidosis
- Symptoms

Answer 12

CNS Effects
- Lethargy, Confusion, Coma

Hyperkalemia

Hyperventilation

Insulin Resistance

Nausea and Vomiting

Question 13

Primary Respiratory Acidosis
- Causes

Answer 13

Determine by Anion Gap
[Na+] - [Cl-] - [HCO3-]

Question 14

Anion Gap
- Thresholds

Answer 14

Equal to 12
- Acidosis not caused by Anion gap

Greater than 14
- Acidosis is likely caused by an excess of unmeasured anions

Less than 14
- Acidosis is likely caused by a lack of excess unmeasured anions

Question 15

Normal Anion Gap Acidosis
- Cause

Answer 15

Hyperalimentation
Acetazolamide
Renal tubular acidosis
Diarrhea/dilutional (rapid saline administration)
Ureteral diversion
Pancreatic fistula

Question 16

Increased Anion Gap Acidosis
- Cause

Answer 16

Methanol/metformin
Uremia
Diabetic ketoacidosis
Propofol/paraldehyde
Iron/isoniazid
Lactate/linezolid
Ethylene glycol
Salicylates/starvation

Question 17

Decreased Anion Gap Acidosis
- Cause

Answer 17

Uncommon

Associated with hypoalbuminemia
- albumin is a unmeasured ion
- Low albumin leads to lower anion gap

Question 18

Flow chart for Acid Base Disorders

Answer 18

1. Assess pH
   2a: Assess pCO2
   - <40mm Hg = Respiratory Alkalosis
   - >40mm Hg = Respiratory Acidosis

2b: Assess HCO3-
- <22mEq/L = Metabolic Acidosis
- >22mEq/L = Metabolic Alkalosis

3. Only for Metabolic Acidosis
   - Assess Anion Gap
   (Na - Cl - HCO3)