SAQ 1420 – Hypoxic breathlessness with CXR and arterial blood gas

A 35-year-old man has presented to the ED with 24 hours of progressive breathlessness.

On assessment, he has increased work of breathing and is hypoxic on room air.

A chest X-ray is displayed below.

List three abnormalities on the CXR.

(Marked out of 3.0)

/ 3

Give two likely diagnoses. For each, list three investigations or findings that would help support that diagnosis.

(Marked out of 8.0)
Diagnosis | Investigation or supportive finding<br /> |<br /> |<br /> |<br /> |<br /> |<br /> |

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An arterial blood gas taken from the patient is displayed below.

ABG parameter	Result	Reference range
FiO2	1.0 (15 L/min via non-rebreather mask)
pH	7.11	7.35-7.45
pCO2	61 mmHg	35-45 mmHg
pO2	158 mmHg
HCO3	19 mmol/L	22-28 mmol/L
Base excess	-12 mmol/L	-3 to +3 mmol/L
Na	141 mmol/L	135-145 mmol/L
K	3.8 mmol/L	3.5-5.0 mmol/L
Cl	105 mmol/L	95-110 mmol/L
Glucose	10.7 mmol/L	3.0-7.0 mmol/L

List two acid-base abnormalities shown on the ABG, with supporting evidence.

(Marked out of 4.0)
Acid-base abnormality | Supporting evidence<br /> |<br /> |

/ 4

Calculate or interpret the anion gap, delta gap or ratio, and A-a gradient. State the clinical implication of the gas exchange abnormality.

(Marked out of 9.0)
Calculation / interpretation | Result or implication<br /> Anion gap |<br /> Delta gap / ratio |<br /> A-a gradient |<br /> Clinical implication |

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Total Score: 0 / 24

Percentage: 0%