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ABG interpretation
Reading File
analyse_media
Finding Sources
I have all the values clearly extracted. Here is the complete ABG interpretation:
ABG Interpretation - Alida Khatun (F/16D)
Sample: Arterial | FiO2: 21% (Room air) | Temp: 37.0°C | Date: 08-Aug-2026
Step 1: Key Values at a Glance
| Parameter | Value | Reference | Status |
|---|---|---|---|
| pH | 7.415 | 7.35-7.45 | ✅ Normal |
| pCO2 | 31.7 mmHg | 35.0-45.0 | 🔻 LOW |
| HCO3 (actual) | 19.9 mmol/L | 22-26 | 🔻 LOW |
| BE(ecf) | -4.7 mmol/L | -2 to +2 | 🔻 Negative |
| pO2 | 83 mmHg | 83-108 | ✅ Normal (low normal) |
| sO2 | 97% | ✅ Normal | |
| Lactate | 1.37 mmol/L | 0.5-1.6 | ✅ Normal |
Step 2: Primary Disorder
pH = 7.415 - Normal, but the primary disturbance is hidden:
- HCO3 is LOW (19.9) → points to metabolic acidosis
- pCO2 is LOW (31.7) → points to respiratory alkalosis
Since pH is in the normal range but trending alkalotic (>7.40), and both HCO3 and pCO2 are low, this is a mixed disorder.
Primary disorder: Metabolic Acidosis (low HCO3 of 19.9, negative BE of -4.7)
Step 3: Compensation Check
For metabolic acidosis, expected pCO2 (Winter's formula):
Expected pCO2 = (1.5 × HCO3) + 8 ± 2 = (1.5 × 19.9) + 8 = 29.85 + 8 = 37.85 ± 2 = 35.85 - 39.85 mmHg
Measured pCO2 = 31.7 mmHg → this is BELOW the expected range
➡️ This means there is concomitant primary respiratory alkalosis in addition to the metabolic acidosis.
Diagnosis: Mixed Metabolic Acidosis + Respiratory Alkalosis
(The two disorders are partially offsetting each other, keeping the pH near normal)
Step 4: Anion Gap
Anion Gap (reported) = 1 mmol/L ← This is reported directly on the ABG
However, calculating manually:
AG = Na⁺ - (Cl⁻ + HCO3⁻) = 132 - (114 + 19.9) = 132 - 133.9 = -1.9 mmol/L
This is a very low / negative anion gap - most likely due to hypoalbuminemia (Hb 9.1 g/dL on CBC, likely low albumin too) or the reported hyperchloremia (Cl⁻ = 114, which is HIGH ↑).
This points to Normal Anion Gap (Hyperchloremic) Metabolic Acidosis - likely causes:
- Diarrhea (most common)
- RTA (renal tubular acidosis)
- GI bicarbonate loss
Step 5: Oxygenation Assessment
| Parameter | Value | Interpretation |
|---|---|---|
| pO2 | 83 mmHg | Low-normal for room air |
| sO2 | 97% | Normal |
| pO2(A-a) gradient | 29 mmHg | Mildly elevated (normal <15-20 mmHg in young) |
| pO2/FiO2 ratio | 397 | Normal (>300 = no ARDS) |
| RI (Respiratory Index) | 0.34 | Normal (<1.0) |
The slightly elevated A-a gradient (29 mmHg) suggests mild V/Q mismatch or early parenchymal issue, but oxygenation is currently maintained.
Step 6: Electrolyte Abnormalities
| Electrolyte | Value | Status | Significance |
|---|---|---|---|
| Na⁺ | 132 mmol/L | 🔻 LOW | Mild hyponatremia |
| K⁺ | 2.7 mmol/L | 🔻 LOW | Hypokalemia - significant! |
| Ca²⁺ | 0.74 mmol/L | 🔻 LOW | Ionized hypocalcemia |
| Cl⁻ | 114 mmol/L | 🔻 HIGH | Hyperchloremia |
| Glucose | 5.8 mmol/L | ✅ Normal | |
| Lactate | 1.37 mmol/L | ✅ Normal |
Hypokalemia (K⁺ 2.7) is clinically significant and consistent with GI losses (diarrhea).
mOsm = 269 mOsm/L - slightly low (normal 280-295), consistent with mild hypo-osmolality.
Step 7: CBC Correlation
From the side panel:
- Hb: ~10.9 g/dL - mild anaemia
- WBC: 12,600 - mild leukocytosis (possible infection/stress)
- Hct on ABG: 27% (low, consistent with anaemia)
- tHb (estimated): 9.1 g/dL - significant anaemia
Summary Diagnosis
Mixed Metabolic Acidosis (Normal Anion Gap / Hyperchloremic) + Primary Respiratory Alkalosis
- Likely cause: Diarrhea (explains NAGMA + hypokalemia + hyponatremia)
- Respiratory alkalosis: possibly from compensatory hyperventilation overshooting, fever, pain, or anxiety
- Significant electrolyte derangements: Hypokalemia, Hyponatremia, Ionized Hypocalcemia
- Mild anaemia (Hb ~10.9 g/dL)
- pH is near-normal due to the opposing effects of the two disorders
Immediate Clinical Action Points
- Correct hypokalemia (K⁺ 2.7) - IV/oral KCl supplementation
- Address the cause - rule out acute diarrhea, look for RTA if no GI loss
- Correct ionized hypocalcemia (Ca²⁺ 0.74)
- Monitor respiratory status - find cause of respiratory alkalosis (sepsis? pain? anxiety?)
- Recheck ABG after initial resuscitation
- CBC + CMP to assess albumin (likely low) and renal function
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