A 5-year-old boy with a history of bronchial asthma was rushed to the emergency department with increasing shortness of breath, pyrexia, and a productive cough. He has difficulty communicating due to an inability to complete a sentence. Examination reveals crackles and wheezes in the lower lobes, tachycardia, and a bounding pulse. Arterial blood gas: pH 7.3, PaCO2 68 mmHg, HCO3 28 mmol/L, PaO2 60mmHg. How would you interpret this?

Correct Answer: B

Rationale: The patient has a low pH (acidosis), elevated PaCO2 (respiratory cause), and an increased HCO3, indicating partial compensation. This suggests respiratory acidosis due to CO2 retention from severe asthma exacerbation.

Correct Answer: B

Rationale: Diarrhea leads to metabolic acidosis with a normal anion gap due to excessive bicarbonate loss in stool. This type of acidosis is known as hyperchloremic acidosis, where chloride replaces lost bicarbonate.

Correct Answer: B

Rationale: Diarrhea leads to metabolic acidosis with a normal anion gap due to excessive bicarbonate loss in stool. This type of acidosis is known as hyperchloremic acidosis, where chloride replaces lost bicarbonate.

Correct Answer: B

Rationale: Infants with large VSDs often experience poor growth due to increased metabolic demand and heart failure.

Correct Answer: A

Rationale: Second-generation H1 antihistamines are first-line for chronic urticaria due to their efficacy and fewer side effects.