Arterial Blood Gas Flashcards
Information From Arterial Blood Gasses
Oxygenation
Ventilation
Acid/base
First Choice for ABGs
Radial artery
Other Possible Arteries for ABGs
Femoral
Brachial
Complications of ABGs
Hematoma
Arterial damage
Stinger (if you hit the nerve)
Normal pH Range
7.35-7.45
Normal CO2 Range
35-45 mmHg
Normal PaO2 Range
83-102 mmHg
Normal HCO3 Range
22-28 mmol/L
Normal Anion Gap Range
10-16 mmol/L
What can acidosis cause?
Decreased force of cardiac contraction
Decreased vascular response to catecholamines
Decreased response to the effects and action of certain medications
What can alkalosis interfere with?
Tissue oxygenation
Neurological and muscle function
Factors that Control pH
Diet Metabolic production of CO2 Regulation through the GI tract Influence of other electrolyte Buffers
3 Systems that Maintain Body pH
Chemical buffering
Respiratory center
Kidneys
Main Chemical Buffer
Carbonic acid system
H2O + CO2 -> H2CO3 -> HCO3 + H
What concentrations trigger the respiratory center as the respiratory buffer?
CO2
Carbonic acid
HCO3
What is altered to increase or decrease ventilation?
Respiratory rate
Tidal volume
Length of Time for the Respiratory Buffer
1-3 minutes
Length of Time for the Renal Buffer
Hours to days
More powerful regulatory system
Define Chemical Buffer
System of one or more compounds that act to resist pH changes when strong acid or base is added
Types of Chemical Buffer Systems
Bicarbonate buffer system
Phosphate buffer system
Protein buffer system
Respiratory Acidosis: pH, CO2, Causes
pH: down
CO2: up
Cause: hypoventilation
Causes of Respiratory Acidosis
CNS depression Impaired muscle function Pulmonary disorders Massive PE Hypoventilation
Signs and Symptoms of Respiratory Acidosis
Dyspnea Respiratory distress Shallow respiration Headache Restlessness Confusion Tachycardia Dysrhythmias
Management of Respiratory Acidosis
Increase the ventilation
Treat pneumothorax, pain, and CNS depression
May require mechanical ventilation
Causes of Respiratory Alkalosis
Psychological responses Pain Increased metabolic demands Respiratory stimulants CNS lesions
Reasons for Increased Metabolic Demands
Fever
Sepsis
Pregnancy
Thyrotoxicosis
Signs and Symptoms of Respiratory Alkalosis
Light headedness Numbness Tingling Confusion Inability to concentrate Blurred vision Dysrhythmias and palpitations Dry mouth Diaphoresis Tetanic spasms of the arms and legs
Metabolic Acidosis: pH, HCO3
pH: low
HCO3: low
Causes of Metabolic Acidosis
Renal failure DKA Anaerobic metabolism Starvation Salicylate intoxication Sepsis
Signs and Symptoms of Metabolic Acidosis
Headache Confusion and restlessness progressing to lethargy Stupor or coma Dysrhythmias Kussmaul's respirations Warm, flushed skin N/V
Management of Metabolic Acidosis
Treat the cause Hypoxia will produce metabolic acids Restore tissue perfusion Use of bicarbonate if indicated Hydration
Metabolic Alkalosis: pH, HCO3
pH: high
HCO3: high
Causes of Metabolic Alkalosis
Ingestion of excess antacids Excess use of bicarbonate Use of lactate in dialysis Protracted vomiting Gastric suction Hypochloremia Excess use of diuretics High levels of aldosterone
Signs and Symptoms of Metabolic Alkalosis
Dizziness Lethargy Disorientation Seizures Coma Weakness Muscle twitching Muscle cramps & tetany N/V Respiratory depression
Define Base Excess
Calculated value estimates that metabolic component of an acid/base abnormality
How much of Cl is reabsorbed under normal pH conditions?
99%
What happens to Cl- reabsorption when acidosis is present?
Fewer ions are reabsorbed
Anion Gap Equation
Anion gap = Na - (Cl + bicarb)
Define Partial Compensation
pH remains outside the normal range
Define Full Compensation
pH has returned within the normal range
Compensation in Primary Respiratory Acidosis
Increased PaCO2
Decreased pH
Increased HCO3
