A ACCS Acute Medicine (CT1) station on MedMock, start to finish

Welcome to the clinical station. I'll read you the scenario, then ask you some questions. You're the FY2 on the acute medical unit on a night shift. A nurse asks you to review a 72-year-old man in bed 12, admitted four hours ago with an exacerbation of COPD, because he's become more drowsy over the last hour. His respiratory rate is 28, oxygen saturations are 96% on 15 litres via a non-rebreathe mask, heart rate 112, blood pressure 138 over 84 and temperature 37.6. He opens his eyes to voice. What would you do?

I'd go and see him straight away. I'm worried he's retaining carbon dioxide: he's drowsy, breathing fast and saturating at 96% on 15 litres, when a patient with COPD who's at risk of hypercapnia usually has a target of 88 to 92%. His NEWS2 is well above 7, so he needs an emergency response. I'd ask the nurse to stay with me and assess him from A to E, treating as I go. Airway: is he talking and protecting his airway? Breathing: his work of breathing, whether he can finish sentences, air entry, wheeze, and signs of a pneumothorax such as unequal air entry or a deviated trachea. I'd take an arterial blood gas straight away and then step his oxygen down to a 28% Venturi mask, aiming for 88 to 92%. I wouldn't take the oxygen off altogether, because stopping it suddenly can make his oxygen levels fall dangerously. Circulation: pulse, blood pressure, capillary refill, IV access with bloods including a full blood count, U&Es and CRP, cultures if he spikes a temperature, and an ECG. Disability: his GCS, pupils, a capillary glucose, and I'd check the drug chart for opioids or sedatives. Exposure: his temperature, his calves and any other source of infection. Because he's drowsy, I'd call the medical registrar early rather than wait for the gas result.

He rouses to voice and answers in short phrases. There's widespread wheeze with reduced air entry at the right base, and his trachea is central. His capillary glucose is 6.8 and he hasn't been given any opioids or sedatives. The gas, taken while he was still on 15 litres, shows a pH of 7.24, pCO2 9.8 kPa, pO2 14.2 kPa, bicarbonate 31 and lactate 1.1. How do you interpret that, and what's your differential for his drowsiness?

It's a respiratory acidosis: the pH is low and the CO2 is high, so he's in type 2 respiratory failure. The raised bicarbonate suggests some chronic CO2 retention that his kidneys have partly compensated for, but the low pH tells me there's an acute rise on top, so it's acute-on-chronic hypercapnic respiratory failure. His pO2 is more than he needs, which makes me think the high-flow oxygen has contributed to the CO2 rise. But on 15 litres I'd expect it to be much higher than 14.2, so there's also a real problem with his gas exchange. The normal lactate is reassuring. For his drowsiness, the most likely cause is CO2 narcosis from the exacerbation, made worse by the uncontrolled oxygen. I'd also think about the trigger and anything alongside it: pneumonia is likely with the reduced air entry at the right base, but I'd consider a pneumothorax, a PE, heart failure or a cardiac event, and an intracranial cause if he doesn't wake up as his CO2 comes down. His glucose and drug chart have ruled out hypoglycaemia and sedating drugs.

What's your management now?

He stays on the 28% Venturi mask, titrated to 88 to 92%, and I'd make sure that target range is prescribed on his chart. I'd give nebulised salbutamol and ipratropium driven by air rather than oxygen, with nasal cannula oxygen alongside if his saturations drop during the nebulisers. He should have steroids, by mouth if he can swallow safely and otherwise IV, and given the signs at the right base I'd start antibiotics in line with local guidance and send a sputum sample. He needs a portable chest X-ray, to look for pneumonia and to rule out a pneumothorax, which matters before any NIV. I'd repeat the gas within 30 to 60 minutes of changing his oxygen. If he's still acidotic, with a pH below 7.35 and a CO2 above 6.5 kPa despite that treatment, he meets the criteria for NIV and it shouldn't be delayed. Before it starts, the registrar and I need a clear, documented escalation plan: whether he'd be for intubation and intensive care if NIV fails, or whether NIV is his ceiling. The lower his pH, the more likely NIV is to fail, so if he is for escalation I'd want critical care involved early. I'd avoid anything sedating and keep him on close observations.

What further information would you want?

First, his baseline: previous gases and bicarbonate to see whether he's a known CO2 retainer, whether he carries an oxygen alert card or uses home oxygen or home NIV, how often he's been admitted, and whether he's needed NIV or intensive care before. Then his exercise tolerance, frailty and other conditions, and whether there's a ReSPECT form, a DNACPR decision, an advance decision to refuse treatment or anyone with lasting power of attorney for health, because those shape his escalation plan. About this admission, I'd want to know what treatment he's had since he arrived, how his saturations and oxygen have changed through the evening, and when he was put on 15 litres and why. And, if he's able to tell us, what he wants himself, and who his next of kin is.

His chest X-ray shows hyperexpanded lungs with right lower zone consolidation and no pneumothorax. The nurse tells you she turned his oxygen up to 15 litres about an hour ago because his saturations had dropped to 85%, and there's no target range on his drug chart. How would you handle that with her?

I'd be supportive. She was right to act on saturations of 85%, and right to call me when he became drowsy, so I'd thank her for that. Once he's stable, I'd have a quiet word to explain why patients like him have a target of 88 to 92%, and that the safer step is to increase the oxygen gradually, for example with a Venturi mask, and ask for a review at the same time. The bigger gap is that no target range was prescribed, and that's the medical team's responsibility, so I'd prescribe it now and make sure it's handed over. Because the oxygen may have contributed to his deterioration, I'd complete an incident report so it's looked at as a system issue rather than to blame anyone, and I'd tell the registrar and the nurse in charge. I'd also discuss with the registrar how we explain it openly to him and his wife, in line with our professional duty of candour.

Thank you. The registrar is at a cardiac arrest and will be about 20 minutes. His wife arrives at the bedside and asks you, "Is he dying?" What would you do?

First I'd make sure he's safe while the registrar is tied up: the nurse stays with him on close observations, I'd ask the critical care outreach team to review him, and I'd have a low threshold for a crash call if he deteriorates. Then I'd introduce myself to his wife and, with the nurse at his bedside, speak to her somewhere quieter nearby. I'd answer honestly: "He is very unwell. His lungs aren't clearing carbon dioxide properly, which is why he's so sleepy. We've changed his oxygen and started treatment for a chest infection, and within the next hour we'll know whether that's enough. If it isn't, he may need a tight-fitting mask that helps his breathing. Many people improve with that, but I can't promise he will, and there's a real chance he could become more unwell." I wouldn't give false reassurance. I'd pause and let her react, then ask whether he's ever talked about what he'd want if he became this unwell, explaining that it helps us understand what matters to him but that she isn't being asked to make the decision. I'd tell her the registrar will come and speak to her, and I'd document the conversation.

Forty-five minutes after the oxygen change and nebulisers, his repeat gas on 28% shows a pH of 7.28 and pCO2 8.9 kPa, with saturations of 90%. He's no more alert. The registrar has just finished at the arrest and phones you. Please hand him over; you have one minute.

Situation: I'm the FY2 on AMU, calling about the 72-year-old man in bed 12 admitted this evening with an exacerbation of COPD. He's drowsy with acute-on-chronic type 2 respiratory failure, and I think he needs NIV, so I'd like you to review him now. Background: he has COPD, and I'm still gathering his baseline and checking whether he has a ReSPECT form. He'd been put on 15 litres via a non-rebreathe an hour before I saw him, with no target range prescribed. Assessment: when I saw him he was rousable to voice only, respiratory rate 28, heart rate 112, blood pressure 138 over 84, temperature 37.6. His first gas on 15 litres showed pH 7.24, CO2 9.8, pO2 14.2 and bicarbonate 31. I stepped him down to a 28% Venturi mask, and he's had nebulisers, steroids and antibiotics for a right lower zone pneumonia on X-ray, with no pneumothorax. His repeat gas after 45 minutes is pH 7.28, CO2 8.9, saturations 90%, and he's no more alert. I've asked outreach to see him. Recommendation: he meets the criteria for NIV. Please review him now to start it, agree his ceiling of care and decide whether critical care should be involved. His wife is here and would like to speak to you. I'll stay with him and keep repeating his observations.

Thank you, that's the end of the station.