ABG Part-5 | ABG Interpretation Step-by-Step | Acid-Base Disorders & Common Lab Values

Confused by ABG interpretation and not sure where to start when you see pH, PaO₂, PaCO₂ and HCO₃⁻ on an arterial blood gas report? In this lecture, we take a step-by-step approach to arterial blood gas (ABG) analysis and bring together the concepts of oxygenation, ventilation and acid–base balance to understand what the numbers are actually telling us. Instead of memorizing isolated ABG values, we build a systematic approach that helps you identify the primary abnormality, understand compensation, and recognize when more than one acid–base disorder may be present. In this video, you will learn: 🔹 The important ABG normal values and what each parameter means 🔹 How to interpret pH, PaO₂, PaCO₂, SaO₂, HCO₃⁻ and Base Excess 🔹 How PaO₂ reflects oxygenation and PaCO₂ reflects ventilation 🔹 How to recognize hypoxaemia, hypercapnia, hypoventilation and hyperventilation 🔹 How to distinguish Type 1 and Type 2 respiratory impairment/failure 🔹 How to identify respiratory acidosis and respiratory alkalosis 🔹 How to identify metabolic acidosis and metabolic alkalosis 🔹 How to recognize uncompensated, partially compensated and compensated acid–base disorders 🔹 How the lungs and kidneys compensate for acid–base disturbances 🔹 How to recognize mixed respiratory and metabolic acid–base disorders 🔹 Why a normal pH does not always mean a normal acid–base status 🔹 How to determine which abnormality is more likely to be the primary disorder 🔹 Why compensation has an expected range and does not simply continue indefinitely 🔹 How inappropriate compensation can suggest a mixed acid–base disorder 🔹 The basic concept of the A–a gradient and its role in assessing oxygenation A simple way to approach ABG interpretation We begin by looking at oxygenation and ventilation using PaO₂ and PaCO₂. Then, we bring in pH and HCO₃⁻ to determine whether the primary problem is respiratory or metabolic. Finally, we assess compensation and consider whether the pattern suggests a single acid–base disorder or a mixed disorder. This systematic approach can make ABG analysis much easier to understand and is especially useful when preparing for MBBS, NEET PG, FMGE, USMLE and other medical examinations. Whether you are learning arterial blood gas interpretation for the first time or revising acid–base disorders for an exam, the goal of this lecture is to help you understand the logic behind ABG interpretation rather than simply memorize patterns. 📌 If you find ABG interpretation confusing, watch the lecture from beginning to end and follow the decision-making process step by step. 💬 Comment below: Which part of ABG interpretation do you find most difficult — compensation, mixed disorders, Type 1 vs Type 2 respiratory failure, or acid–base disorders? 👍 Like the video if it helped you understand ABG analysis more clearly. 📤 Share it with your medical-student friends and classmates. 🔔 Subscribe to Whiteboard Medicine Simplified for more simplified, high-yield medical lectures, physiology, pharmacology and clinical concepts. #ABGInterpretation #ABGAnalysis #ArterialBloodGas #AcidBaseBalance #AcidBaseDisorders #RespiratoryAcidosis #MetabolicAcidosis #RespiratoryFailure #MedicalStudents #NEETPG