Station - Instructions for candidate
You are an intern in the Emergency Department of a Perth teaching hospital.
Bruce Whitlock, a 71-year-old retired boilermaker with severe COPD, has been brought in by ambulance with three days of worsening breathlessness and green sputum. The paramedics found his saturations at 84 percent and gave him 15 L/min of oxygen by mask; he has become drowsy on the way in. He is on a monitored bed with a nurse. The handover, his clinic letter and his arrival blood gas are printed on your sheet.
| Ambulance handover | Three days of increased breathlessness, purulent sputum and fever; SpO2 84% on room air at home, 15 L/min oxygen by non-rebreather mask started; increasingly drowsy in transit. On arrival: RR 24, SpO2 99% on 15 L/min, HR 108, BP 142/84 mmHg, temperature 38.1 C, GCS 13 (E3 V4 M6), glucose 8.1. Medicines: tiotropium, budesonide-formoterol, salbutamol as needed. No allergies. Smokes 10 a day. |
|---|---|
| Respiratory clinic letter (six months ago) | Severe COPD, FEV1 38% predicted; two admissions last year. Clinic arterial gas on room air: pH 7.38, pCO2 55 mmHg, pO2 62 mmHg, HCO3 31. Independent at home with his wife, walks to the shops on good days. Advice: controlled oxygen only, target 88-92%. |
Results provided:
Arterial blood gas on arrival (15 L/min oxygen by non-rebreather mask)
| Item | Value | Reference range |
|---|---|---|
| pH | 7.24 | 7.35-7.45 |
| pCO2 | 78 mmHg | 35-45 mmHg |
| pO2 | 110 mmHg | 80-100 mmHg (room air) |
| HCO3 | 32 mmol/L | 22-28 mmol/L |
| Base excess | +4 | -3 to +3 |
| Lactate | 1.2 mmol/L | <2.0 mmol/L |
| Na, K, Glucose | 138, 4.0, 8.1 mmol/L | 135-145; 3.5-5.2; 4.0-7.8 |
Taken 10 minutes after arrival with the mask still on.
Your tasks are to:
- Interpret the blood gas provided.
- State your most likely diagnosis and differential diagnoses to the examiner.
- Outline your immediate management plan to the examiner.
- The examiner will ask you two questions at the end.
- You do NOT need to take a history or examine the patient; the nurse can answer brief questions and will carry out your instructions.
- The patient is on a monitor; further results are available from the examiner on request.
This is a 10-minute station, with 2 minutes of reading time.