Abcs Of Abg's Arterial Blood Gas Analysis - Synder

Front 1

What are ABGs?

Back 1

-arterial blood gas
-assessment of arterial blood for oxygenation and gas exchange (CO2) and AB status of pt

Front 2

What are directly measured components of ABGs?

Back 2

-pH = 7.35 - 7.45
-pO2 = 80-100
-pCO2 = 35-45 (40)
***Calculated is [HCO3-] = 22-28 (24)

Front 3

*What is the definition of respiration?

Back 3

-the mechanical act of breathing, circulation of blood thru pulmonary vascular bed, exchange of O2 and CO2 at alveolar capillary interface

Front 4

What does respiration depend on?

Back 4

-automatic control (medulla, pons)
-volition
-diaphragm
-ribs and muscle of thorax
-integrity of circulation
-number and condition of alveoli

Front 5

What is pulmonary ventilation?

Back 5

-the amount of gas brought into and/or out of lungs
-usually referred to in terms of CO2 excretion

Front 6

**Hypoventilation

Back 6

-decreased excretion of CO2
-and accumulation in blood

Front 7

**Hyperventilation

Back 7

-increased exretion of CO2
-reduced in blood

Front 8

***What will a pCO2 increase cause?

Back 8

-pH to fall and in response kidneys generate bicarb to offset the acid and blunt the degree of fall in pH

Front 9

***What is the Henderson Equation?

Back 9

[H+] = 24 x pCO2 / [HCO3-]

Front 10

What are potential causes of decreased CO2 excretion in reference to:

Decreased perfusion?

Back 10

-PNA
-ARDS
-Pulmonary embolism
-Cardiac arrest
-COPD/Emphysema

Front 11

What are potential causes of decreased CO2 excretion in reference to:

Obstruction?

Back 11

-this can occur anywhere from mouth to nose to small airways
-COPD/emphysema
-Severe asthma

Front 12

What are potential causes of decreased CO2 excretion in reference to:

Thorax

Back 12

-Fail chest - trauma
-Hemothorax
-Pneumothorax

Front 13

What are potential causes of decreased CO2 excretion in reference to:

Musculature

Back 13

-Myasthenia
-Hypokalemia
-Hypophosphatemia
*remember it is the chest that expands the lungs; and condition that causes the muscle to not work will cause dec CO2 excretion

Front 14

What are potential causes of decreased CO2 excretion in reference to:

CNS

Back 14

-sedation
-CNS lesions
-Drugs
-Myxedema (hypothyroid crisis)
-Paralyzing agents
-cord injury (C3 or above), polio, ALS

Front 15

****Primary CO2 retention from any of the above conditions will lead to?

Back 15

-Respiratory ACIDOSIS

Front 16

What are the effects of Respiratory Acidosis in reference to:
1. NM
2. Cardiovascular
3. Labs

Back 16

1. anxiety, stress, lethargy, coma, dilerium, seizures, tremors
2. Tachycardia, arrhythmia, vasodilation
3. inc [HCO3-], hyperphosphatemia*

Front 17

Disorders that cause hyperventilation (inc excretion, inc the pH)

Hypoxemia

Back 17

-V/Q mismatch, shunts, hypotension, high altitude

Front 18

Disorders that cause hyperventilation (inc excretion, inc the pH)

Drugs and hormones

Back 18

-Salicylates and ASA
-T4
-Progesterone (pregos)
-catecholamines
-xanthines

Front 19

Disorders that cause hyperventilation (inc excretion, inc the pH)

Specific conditions

Back 19

-Cirrhosis, hyponatremia, sepsis, pregos, heat stress, ventilators

Front 20

****Primary to increased CO2 excretion leads to?

Back 20

-Respiratory ALKALOSIS

Front 21

***Effects of Respiratory Alkalosis on:
1. NM
2. CV
3. GI
4. Labs

Back 21

1. Confusion, seizures, syncope
2. Tachy, angina, arrhytmia, ECG changes
3. N/v
4. dec bicarb, hypophasphatemia, dec ionized Ca++

Front 22

****HYPOXEMIA IS...?

Back 22

-the MOST potent stimulus to respiration
-THE MOST IMPORTANT AND URGENT ABNORMALITY TO CORRECT

Front 23

*What happens when pCO2 is abnL?

Back 23

-pH is deranged b/c change in pCO2 and metabolic compensation begins
-compensation is demonstrated by change in [HCO3-] and is PREDICTABLE

Front 24

*Metabolic Acidosis

Back 24

-[HCO3-] is decreased
-causes pH to fall
-pCO2 decreases (hypervent) to compensate

Front 25

*Metabolic Alkalosis

Back 25

-[HCO3-] is increased
-causes pH to rise
-pCO2 rises (hypovent) to compensate

Front 26

***What are the 2 types of metabolic acidosis?

Back 26

1. normal anion gap (~12)
2. increased anion gap
- anion gap = [Na+] - ([Cl-] + [HCO3-])

Front 27

***NORMAL ANION GAP:

HARDUP

Back 27

-Hyperalimentation
-Acetazolamide
-Renal tubular acidosis
-Diarrhea
-Ureteroilostomy
-Pancreatic fistual
***RTA and Diarrhea are MC

Front 28

***INCREASED ANION GAP

AMPLESUDS

Back 28

-alcoholic ketoacidosis, methanol, paraldehyde, lactate, ethylne glycol, ASA, Uremia, diabetic ketoacidosis, starvation

Front 29

*Urine anion gap

Back 29

-different from serum anion gap
-UAG > 0 suggests renal causes
-UAG < 0 suggests GI causes

Front 30

SIMPLE ACID- BASE DISORDERS

Back 30

MEMORIZE CHART IN DR. SNYDER'S NOTES

Front 31

What is the Winter's Formula?

Back 31

-for metabolic acidosis

(1.5 x [HCO3-]) + 8 +/- 2

Front 32

***Do A/B disorders compensate to 7.4?

Back 32

-AB disorders never compensate completely to 7.4
-a pH of 7.4 suggests that there is a mixed disorder

Front 33

What is the delta gap?

Back 33

-it is the anion gap -12

Front 34

What is the "Starting bicaarbonate"

Back 34

= the calculated delta gap + [HCO3-]

Front 35

What is going on if the "starting bicarb" is > 24?

Back 35

-there is a mixed metabolic alkalosis AND metabolic acidosis

Front 36

What is going on if the "starting bicarb" is < 24?

Back 36

-there is mixed normal anion gap (RTA, diarrhea) and increased anion gap metabolic acidosis