acid-base disorders

A 70-year-old man with severe COPD (FEV1 30% predicted), on triple inhaled therapy and supplemental oxygen, presents with a 3-day history of increased dyspnoea, productive cough with purulent sputum, and reduced exercise tolerance. He denies fever or chest pain. On examination, he is tachypnoeic (RR 24), saturating 88% on 2 L/min oxygen, with diffuse wheeze and prolonged expiration. His chest X-ray shows hyperinflation but no new infiltrates. His arterial blood gas on 2 L/min oxygen shows pH 7.32, pCO2 68 mmHg, pO2 55 mmHg, bicarbonate 35 mmol/L. Given this presentation, what is the most appropriate immediate management step?

A 3-week-old male presents with non-bilious projectile vomiting after each feed. He is otherwise well-appearing. An abdominal X-ray is unremarkable. An upper GI contrast study is performed, and relevant images are shown. What is the MOST likely acid-base disturbance in this patient?

A 6-week-old male infant presents to the emergency department with a 2-week history of progressively worsening non-bilious vomiting, which has become projectile over the past few days. His parents report he is feeding eagerly but vomits most feeds shortly after completion. He has had fewer wet nappies than usual and appears more lethargic. On examination, he is irritable but consolable. His weight is below the 3rd percentile, having dropped from the 10th percentile at birth. Vital signs are: Temperature 36.8°C, Heart Rate 155 bpm, Respiratory Rate 40 bpm, Blood Pressure 85/50 mmHg, Oxygen Saturation 98% on room air. Capillary refill time is 3 seconds. Abdominal examination reveals a soft, non-distended abdomen with active bowel sounds; no palpable masses are appreciated. Initial blood gas shows pH 7.52, pCO2 40 mmHg, Bicarbonate 32 mmol/L, Na+ 132 mmol/L, K+ 3.0 mmol/L, Cl- 88 mmol/L. A point-of-care ultrasound was performed, and the image provided was obtained. Considering the clinical presentation, the laboratory results, and the findings demonstrated in the image, which of the following represents the most appropriate immediate therapeutic intervention?

A 68-year-old man with a history of severe chronic obstructive pulmonary disease (COPD) and known secondary pulmonary hypertension presents with increasing dyspnoea and peripheral oedema. His arterial blood gas on room air shows pH 7.31, PaCO2 68 mmHg, PaO2 48 mmHg, and SaO2 80%. His chest X-ray shows hyperinflation and prominent pulmonary arteries. Which of the following interventions is most likely to acutely decrease his pulmonary vascular resistance?

A 4-week-old male presents with non-bilious emesis. An upper GI series is performed (image shown). What acid-base abnormality is MOST likely?

A 6-week-old male presents with persistent non-bilious vomiting after feeding. He appears hungry and has lost weight since birth. Examination reveals visible peristaltic waves across the abdomen. An abdominal ultrasound is performed, as shown. What is the most likely acid-base disturbance seen in this patient?

A 6-week-old male infant presents to the emergency department with a 2-week history of progressively worsening non-bilious vomiting, which has become projectile over the past few days. His parents report he is feeding eagerly but vomits most feeds shortly after completion. He has had fewer wet nappies than usual and appears more lethargic. On examination, he is irritable but consolable. His weight is below the 3rd percentile, having dropped from the 10th percentile at birth. Vital signs are: Temperature 36.8°C, Heart Rate 155 bpm, Respiratory Rate 40 bpm, Blood Pressure 85/50 mmHg, Oxygen Saturation 98% on room air. Capillary refill time is 3 seconds. Abdominal examination reveals a soft, non-distended abdomen with active bowel sounds; no palpable masses are appreciated. Initial blood gas shows pH 7.52, pCO2 40 mmHg, Bicarbonate 32 mmol/L, Na+ 132 mmol/L, K+ 3.0 mmol/L, Cl- 88 mmol/L. A point-of-care ultrasound was performed, and the image provided was obtained. Considering the clinical presentation, the laboratory findings, and the abnormality demonstrated in the provided image, which of the following best explains the mechanism leading to the observed electrolyte and acid-base derangements?

A 5-week-old male presents with non-bilious projectile vomiting. An ultrasound is performed (shown). What acid-base disturbance is MOST likely?