Create two OSPE stations: one on COPD with type 2 respiratory failure based on arterial blood gas findings, and another on pneumothorax based on guideline‑based management.

OSPE Station 1: COPD with Type 2 Respiratory Failure Based on ABG Findings

Station Overview

Time: 10 minutes
Candidate Task: Interpret arterial blood gas results and manage a patient with COPD exacerbation presenting with type 2 respiratory failure

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Clinical Scenario

A 68-year-old male smoker (40 pack-years) presents to the Emergency Department with:

• Increased breathlessness over 3 days
• Productive cough with purulent sputum
• Unable to complete sentences
• Respiratory rate: 32 breaths/min
• Heart rate: 110 bpm
• SpO₂: 84% on room air

Initial ABG on room air shows:

• pH: 7.28
• PaCO₂: 68 mmHg (9.1 kPa)
• PaO₂: 52 mmHg (6.9 kPa)
• HCO₃⁻: 31 mmol/L
• SpO₂: 84%

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Tasks for Candidate

Task 1: ABG Interpretation (3 minutes)

Interpret the arterial blood gas results and answer:

1. What type of respiratory failure is present?
2. Is this acute or acute-on-chronic respiratory failure? Explain your reasoning.
3. What is the significance of the bicarbonate level?
4. Does this patient meet criteria for non-invasive ventilation (NIV)?

Expected Answers:

• Type 2 (hypercapnic) respiratory failure with respiratory acidosis 1
• Acute-on-chronic based on elevated bicarbonate (>28 mmol/L) suggesting chronic CO₂ retention with acute decompensation 1
• Bicarbonate elevation indicates chronic hypercapnia with metabolic compensation 1
• YES - meets NIV criteria: pH <7.35 with PaCO₂ >6 kPa (45 mmHg) and respiratory acidosis 1, 2

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Task 2: Immediate Oxygen Management (3 minutes)

The patient is currently receiving 15L/min via reservoir mask. What should you do?

1. What is the target oxygen saturation for this patient?
2. What oxygen delivery device and flow rate should be used immediately?
3. When should you recheck blood gases?
4. What is the critical danger of the current oxygen therapy?

Expected Answers:

• Target SpO₂: 88-92% for patients with COPD at risk of hypercapnic respiratory failure 1
• Immediate change to 28% Venturi mask at 4 L/min or 24% Venturi mask at 2-3 L/min 1
• Recheck ABG in 30-60 minutes after oxygen adjustment 1
• Risk of worsening respiratory acidosis - excessive oxygen (PaO₂ >10.0 kPa) increases risk of CO₂ retention and acidosis 1

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Task 3: Further Management Decision (4 minutes)

After 45 minutes on 28% Venturi mask, repeat ABG shows:

• pH: 7.26
• PaCO₂: 72 mmHg (9.6 kPa)
• PaO₂: 58 mmHg (7.7 kPa)
• SpO₂: 89%

Answer the following:

1. What is your next management step?
2. What are the specific indications present for this intervention?
3. What additional treatments should be initiated alongside?
4. What would indicate treatment failure requiring escalation?

Expected Answers:

• Start NIV immediately - bilevel positive airway pressure ventilation 1, 2
• Indications present: pH <7.35, PaCO₂ >6 kPa, respiratory acidosis persisting >30 minutes after standard medical management 1
• Additional treatments:
  • Nebulized bronchodilators (salbutamol ± ipratropium) driven by compressed air with supplemental oxygen via nasal prongs at 1-2 L/min 3
  • Systemic corticosteroids (prednisolone 30 mg daily) 3
  • Antibiotics if ≥2 of: increased breathlessness, increased sputum volume, purulent sputum 3
• Treatment failure indicators: pH continues to fall, worsening acidosis, deteriorating consciousness, inability to tolerate NIV 1

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Examiner Marking Guide

ABG Interpretation (3 points):

• Correctly identifies type 2 respiratory failure (1 point)
• Recognizes acute-on-chronic pattern from bicarbonate (1 point)
• Identifies NIV indication (1 point)

Oxygen Management (3 points):

• States correct target SpO₂ 88-92% (1 point)
• Prescribes appropriate Venturi mask concentration (1 point)
• Recognizes danger of excessive oxygen (1 point)

Further Management (4 points):

• Initiates NIV appropriately (1 point)
• Lists correct additional therapies (2 points)
• Identifies treatment failure criteria (1 point)

Total: 10 points

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OSPE Station 2: Pneumothorax Based on Guideline Management

Station Overview

Time: 10 minutes
Candidate Task: Assess chest X-ray findings and manage pneumothorax according to evidence-based guidelines

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Clinical Scenario

A 24-year-old tall, thin male presents with:

• Sudden onset right-sided chest pain 4 hours ago
• Mild breathlessness at rest
• No significant past medical history
• Non-smoker
• Vital signs: BP 125/78, HR 88, RR 18, SpO₂ 96% on room air
• Clinically stable, able to speak in full sentences

Chest X-ray shows: Right-sided pneumothorax with 2.5 cm rim of air at the hilum level

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Tasks for Candidate

Task 1: Classification and Initial Assessment (3 minutes)

1. What type of pneumothorax is this (primary or secondary)?
2. Based on the chest X-ray finding, how would you classify the size?
3. Does this patient require supplemental oxygen? Explain your reasoning.
4. What is the most appropriate initial management approach?

Expected Answers:

• Primary spontaneous pneumothorax (PSP) - young, tall, thin male with no underlying lung disease 4, 5
• Size classification varies by guideline, but 2.5 cm rim indicates significant pneumothorax requiring intervention 4, 5
• No supplemental oxygen required - patient not hypoxaemic (SpO₂ 96%), most patients with pneumothorax are not hypoxaemic 1
• Needle aspiration is the preferred initial treatment over chest tube drainage for PSP 5

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Task 2: Intervention Decision-Making (4 minutes)

You decide to perform needle aspiration. Answer the following:

1. What are the specific advantages of needle aspiration over chest tube drainage for this patient?
2. After successful aspiration with clinical improvement, what is the appropriate next step?
3. Under what circumstances would you admit this patient for observation with high-flow oxygen?
4. If the patient were hypoxaemic (SpO₂ 82%), how would your oxygen management differ?

Expected Answers:

• Advantages of needle aspiration: Less invasive, better tolerated, shorter hospital stay, strong recommendation in guidelines for initial PSP treatment 5
• Next step after successful aspiration: Consider ambulatory management if clinically stable, arrange follow-up imaging, provide safety-netting advice 5
• Admission with high-flow oxygen indications: If aspiration fails, pneumothorax requires drainage, or patient becomes hypoxaemic - use reservoir mask at 15 L/min targeting 100% saturation (oxygen accelerates pneumothorax clearance) 1
• Oxygen for hypoxaemic patient: Reservoir mask at 15 L/min, target saturation 94-98%, pneumothorax needs aspiration or drainage if patient hypoxaemic 1

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Task 3: Recurrence Prevention Counseling (3 minutes)

The patient asks about preventing future episodes. Address:

1. What is the approximate recurrence risk after first PSP?
2. What lifestyle modifications should you advise?
3. When would you recommend early surgical intervention for this first episode?
4. What surgical options exist for recurrence prevention?

Expected Answers:

• Recurrence risk: Approximately 20-30% after first PSP, higher with subsequent episodes 5
• Lifestyle modifications:
  • Avoid air travel until complete resolution confirmed on imaging
  • Avoid scuba diving permanently unless definitive surgical treatment
  • Smoking cessation strongly advised
  • Avoid activities with rapid pressure changes 5
• Early surgical intervention indication: Conditional recommendation for patients who prioritize recurrence prevention over avoiding surgery 5
• Surgical options: Video-assisted thoracoscopic surgery (VATS) with pleurodesis and/or bullectomy 5

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Examiner Marking Guide

Classification and Assessment (3 points):

• Correctly identifies primary spontaneous pneumothorax (1 point)
• Recognizes patient is not hypoxaemic and doesn't require routine oxygen (1 point)
• Recommends needle aspiration as first-line treatment (1 point)

Intervention Management (4 points):

• Explains advantages of needle aspiration (1 point)
• Describes appropriate post-aspiration management (1 point)
• Correctly identifies when to use high-flow oxygen (1 point)
• States correct oxygen delivery for hypoxaemic pneumothorax (1 point)

Recurrence Prevention (3 points):

• Discusses recurrence risk (1 point)
• Provides appropriate lifestyle advice (1 point)
• Explains surgical options appropriately (1 point)

Total: 10 points

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Key Teaching Points for Both Stations

COPD Type 2 Respiratory Failure:

• ABG is essential for diagnosis and monitoring - venous blood gas may be acceptable for pH and HCO₃⁻ but arterial remains gold standard 6, 7
• Target SpO₂ 88-92% in at-risk patients prevents worsening hypercapnia 1
• NIV criteria: pH <7.35 with PaCO₂ >6 kPa (45 mmHg) 1, 2
• Avoid sudden oxygen cessation - causes life-threatening rebound hypoxaemia 1

Pneumothorax Management:

• Most pneumothorax patients are not hypoxaemic and don't require oxygen 1
• Needle aspiration preferred over chest tube for initial PSP treatment 5
• High-flow oxygen only if: admitted for observation or patient is hypoxaemic - accelerates resolution 1
• Conservative management acceptable for minimally symptomatic, clinically stable PSP patients 5