Arterial Blood Gas (ABG) Analyzer
Why Use
The ABG analysis is a systematic approach that, when used in conjunction with patient history and clinical scenario, helps to determine the primary disease process and subsequently calculate any evidence of compensatory process. It also can aid in determining the chronicity of the acid-base disturbance along with any secondary or co-existing acid-base disturbances.
When to Use
ABG analysis is useful when diagnosing or monitoring various respiratory, metabolic, and circulatory disorders. If a respiratory process is present, ABG analysis can help indicate if the process is acute or chronic.
Formula
Pearls / Pitfalls
While the analyzer can often help with analysis, the history of the patient is critical for accurate interpretation.
Management
Management varies significantly depending on the ABG results, along with the clinical scenario.
Critical Actions
1. Ensure proper sampling of blood specimen. 2. Consider repeating ABG if results do not fit the patient history and clinical scenario. 3. A venous blood gas (VBG) can also be checked to see if it correlates with ABG results (only PaO 2 should be different).
Advice
Technique matters when it comes to collecting the blood specimen. Inaccurate results may be due to obtaining a venous sample instead of an arterial sample, the presence of air bubbles in the specimen (lowering PaCO 2 ), or a delay in analyzing the sample (lowering PaO 2 ).
More Information
Metabolic Acidosis (Anion Gap) MUDPILES Methanol Uremia Diabetic Ketoacidosis (check serum ketones) Propylene Glycol or Paraldehydes Isoniazid Lactic Acidosis (check serum lactate) Ethylene Glycol (anti-freeze) Salycylates GOLDMARK Glycols (ethylene or propylene) Oxoporin (reflects fatty liver damage from glutathione consumption, e.g. acetaminophen toxicity) L-Lactate D-Lactate (bacterial form) Methanol Aspirin (salicylate) Renal Failure (BUN uremia) Ketoacidosis Metabolic Acidosis (Non-Anion Gap) GI Loss Diarrhea / Laxatives Fistula, (pancreatic, biliary) Uretero-intestinal diversion (ileal conduit) Renal Loss Renal Tubular Acidosis (Type 1 Distal or Type 2 Proximal) Renal Failure Hyper-kalemia Exogenous Acid HCl Amino Acids FUSED CARS Fistula (pancreatic, biliary) Uretero-gastric conduit Saline admin (dilutional acidosis) Endocrine (hyper-PTH) Diarrhea Carbonic anhydrase inhibitor (acetazolamide) Ammonium chloride Renal tubular acidosis Spironolactone Metabolic Alkalosis Alkaline Input Bicarbonate Infusion Hemodialysis Calcium Carbonate Parenteral Nutrition Proton Loss GI Loss (vomiting, NG suction) Renal loss Diuretics Mineralocorticoids Respiratory Acidosis Airway Obstruction Foreign body, aspiration OSA (obstructive sleep apnea) Laryngo- or broncho-spasm Neuromuscular Myasthenia gravis Hypokalemic periodic paralysis Guillain-Barre Botulism, Tetanus Hypo-kalemia, hypo-phosphatemia Cervical spine injury Morbid obesity Polio, MS, ALS Central Drugs (opiates, sedatives) Oxygen treatment in acute hypercapnia Brain trauma or stroke Pulmonary Pulmonary edema Asthma Pneumonia ARDS COPD Pulmonary Fibrosis Mechanical Ventilation Respiratory Alkalosis Hypoxia High altitude CHF Pulmonary Embolism Lung Disease Pulmonary fibrosis Pulmonary edema Pneumonia Drugs Progesterone Nicotine Stimulation of Respiratory Drive Psychogenic Neurologic (pontine tumor) Sepsis Pregnancy Mechanical ventilation