Abg

Front 1

Arterial Blood Gases

Back 1

Info of clients’ acid-base status

Body’s ability to regulate the pH ( whether compensation is occurring)

Info about overall oxygen status

Front 2

ASSESSMENT OF ACID-BASE STATUS

Back 2

-pH reflects the H+ Ions in the Blood

Normal pH is 7.35 – 7.45

Acidosis pH < 7.35
Alkalosis pH > 7.45

Front 3

Respiratory System (PaCO2)

Back 3

-Maintains pH by excreting CO2 (a volatile acid)
-Rate of excretion of CO2 controlled by medulla oblongata
-Reacts quickly in minutes but is less effective over time
-If respiratory is the cause of acid base imbalance it loses the ability to correct it.

Front 4

RENAL SYSTEM (HCO3)

Back 4

-Reabsorbs and conserves all bicarb (HCO3) it filters and excrete weak acids
-Takes up to 72 hours to reach peak action, but can maintain balance for longer
-If the renal system is the cause of the acid-base imbalance, it loses its ability to correct the ph (i.e. Kidney failure)

Front 5

PCO2 RESPIRATORY PARAMETER

Back 5

Normal pCO2 = 35–45mmHg

↑ pCO2 ( >45) = respiratory acidosis and ↓ in pH
↓ pCO2 (<35) = respiratory alkalosis and ↑ in pH

Front 6

HCO3 METABOLIC PARAMETER

Back 6

-HCO3 is most common base found in blood
-It buffers H+ ions in an acid state
-Is regulated by the kidneys

Normal HCO3 22-26 mEq/L
↑ in HCO3 (>26) = ↑in pH (alkalosis)
↓ in HCO3 (<22) = ↓in pH (acidosis)

Front 7

CAUSES OF RESPIRATORY ALKALOSIS

Back 7

PH > 7.45 CO2 <35

Alveolar Hyperventilation
-Psychogenic (fear, anxiety, pain)
-CNS stimulation
-Hypermetabolic states (fever)
-Mechanical overventilation
-Body’s initial response to hypoxia (pneumonia, heart failure, PE

Front 8

CAUSES OF RESPIRATORY ACIDOSIS

Back 8

PH < 7.35 CO2 > 45

Hypoventilation
-depression of respiratory center (sedatives, narcotics, CVA, cardiac arrest)
-respiratory muscle paralysis (spinal cord injury, Guillain-Barre)
-chest wall disorders (pneumothorax)
-disorders of lung parenchyma (COPD, pneumonia, ARDS, CHF)

Front 9

CAUSES OF METABOLIC ACIDOSIS

Back 9

PH < 7.35 HCO3 < 22

Diabetic ketoacidosis
Starvation
Renal Failure
Lactic Acidosis
Diarrhea
Fistula Drainage

Front 10

CAUSES OF METABOLIC ALKALOSIS

Back 10

PH > 7.45 HCO3 >26

-NG suctioning/vomiting (loss of H+ ions)
-Excess Steroid Administration
-Excessive administration of NaHCO3
-Diuretic Therapy

Front 11

ASSESSMENT OF OXYGENATION

Back 11

paO2 is the amount of oxygen dissolved in blood serum
-Normal values are 80-100

Sa02 is the % of oxygen bound to hemogloblin
-normal value > 95

Front 12

ACID-BASE COMPENSATION

Back 12

-The respiratory and renal system compensate for each other to return the pH to normal
-The system not causing the problem tries to correct the imbalance
-The lung compensate for metabolic disturbances by changing CO2 excretion
-The kidneys compensate for respiratory disturbances by altering bicarb

The goal of compensation is a normal pH

Front 13

Steps for Interpretation of ABGs

Back 13

-Evaluate pH
Is it acidosis or alkalosis?
-Analyze CO2
<35 alkalosis
>45 acidosis
-Analyze HCO3
>26 alkalosis
<22 acidosis
-Determine if CO2 or HCO3 matches the pH alteration
-Determine if body is attempting to compensate

Front 14

ABG examples

Back 14

pH- 7.50→alkalosis
pCO2- 30→alkalosis
HCO3-24→normal

pH alkalosis and pCO2 alkalosis; thus the match indicates respiratory

pH-7.30→acidosis
pCO2-38→normal
HCO3-18→acidosis

Ph acidosis and HCO3 acidosis > metabolic

Front 15

Example of Compensation

Back 15

pH-7.33=acidosis
pCO2-54=acidosis
HCO3-30=alkalosis

pCO2 ‘matches’ pH so the problem is respiratory…so label it respiratory acidosis.
-To compensate the kidneys conserve bicarb; but the pH is not yet normal…so…label it: respiratory acidosis with partial compensation.
-It is ‘complete or total’ compensation when the pH is back to normal!