Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm

    Disease

    Select...

    Specialty

    Select...

    Chief Complaint

    Select...

    Organ System

    Select...

    Patent Pending

    Arterial Blood Gas (ABG) Analyzer

    Interprets ABG.
    Favorite

    INSTRUCTIONS

    This analyzer should not substitute for clinical context. Sodium and chloride are required for anion gap calculation.
    Pearls/Pitfalls
    While the analyzer can often help with analysis, the history of the patient is critical for accurate interpretation.
    mm Hg
    mEq/L
    mEq/L
    mEq/L
    g/dL

    Result:

    Please fill out required fields.

    Next Steps
    Evidence
    Creator Insights

    Advice

    A venous blood gas often correlates well with arterial blood gas findings (except for PaO2) unless values are extremely abnormal, and can often be used successfully as a screening tool.

    Formula

    This tool, developed by Jonathan Chen, MD first determines the primary process by looking at the pH and the PCO2. It then calculates compensations to determine chronicity, compensatory, and co-existing acid-base disturbances.

    Facts & Figures

    Metabolic Acidosis (Anion Gap)

    MUDPILES

    • Methanol
    • Uremia
    • Diabetic Ketoacidosis (check serum ketones)
    • Propylene Glycol (in BZD drips) 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 (salycylate)
    • 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
    Dr. Jonathan Chen

    About the Creator

    Jonathan Chen, MD, PhD is a research fellow in medical informatics, based at the Veteran Affairs Hospital in Palo Alto and Stanford University. He completed the Stanford Internal Medicine residency program and was in the Medical Scientist Training Program (MSTP) and Biomedical Informatics Training (BIT) program at UC Irvine. Dr. Chen co-founded Reaction Explorer, LLC, which offers a unique system for teaching complex problem-solving in organic chemistry with the aid of expert system technology.

    To view Dr. Jonathan Chen's publications, visit PubMed