MRCS Part B Revision · Applied surgical science and critical care
ARDS — MRCS Part B Applied surgical science and critical care
By Dr Richard Miller, MBChB FRCS · Reviewed
ARDS is an applied surgical science and critical care station. Three of the seventeen examined stations in the MRCS Part B OSCE fall in this area. These stations ask you to interpret data and manage a sick surgical patient: a chart, a blood gas, an imaging study or a deteriorating patient on the ward, and the physiology underneath the decision.
What you need to know for the ARDS station
Acute Respiratory Distress Syndrome
Acute respiratory distress syndrome (ARDS) is a severe, life-threatening medical condition characterized by widespread inflammation in the lungs. While ARDS may be triggered by a trauma or lung infection, it is usually the result of sepsis.
ARDS is a disease of the alveoli that leads to decreased exchange of oxygen and carbon dioxide (gas exchange). ARDS is associated with several pathologic changes: the release of inflammatory chemicals, breakdown of the cells lining the lung's blood vessels, surfactant loss leading to increased surface tension in the lung, fluid accumulation in the lung, and excessive fibrous connective tissue formation.
The syndrome has a high mortality between 20 and 50%. The mortality rate with ARDS varies widely based on disease severity, a person's age, and the presence of other medical conditions.
What are you asked at the ARDS station?
The station runs to 15 questions over nine minutes. These are the questions as they are put to you; the model answers are in the question bank.
- How would you approach this situation?
- What does the radiograph show?
- What would your immediate management involve?
- It is now 7 days following the initial NG feeding. The patient has become increasingly hypoxic on blood gas results. The latest of which is shown below pH 7.32 PCO2 50 PO2 105 HCO3- 25 on an FIO2 of 1.0. What does the ABG result show?
- How would you manage the patient now?
- A repeat CXR is performed
What does it show?
- Given the patient’s history and CXR what is the likely disease process?
- What is the definition of ARDS?
- What are the causes of ARDS?
- How could you tell if the pulmonary oedema was cariogenic or non-cardiogenic?
- What is the definition of lung compliance?
- What is lung surfactant composed of, and what purpose does it serve?
And 3 more at this station.
How is the applied surgical science and critical care station marked in MRCS Part B?
Each of these three stations is marked out of 20, split 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. No communication marks are available. The three cover critical care management, interpretation of clinical data, and interpretation of visual information.
FAQ
What does the ARDS station ask?
It opens with "How would you approach this situation?" and runs to 15 questions over nine minutes. Each of these three stations is marked out of 20, split 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. No communication marks are available. The three cover critical care management, interpretation of clinical data, and interpretation of visual information.
What counts as applied surgical science in MRCS Part B?
Three of the seventeen examined stations: critical care management, interpretation of clinical data such as blood results and charts, and interpretation of visual information such as imaging and traces.
How is an applied science station marked?
Out of 20, with 12 marks for clinical knowledge and its application, 4 for clinical and technical skill and 4 for professionalism. Unlike the communication stations, none of the marks are for how you say it.
How much physiology do I need?
Enough to explain the decision you are making. The station rewards applying physiology to the patient in front of you rather than reciting it, so practise talking through why a number changes your management.
How many stations are in the MRCS Part B OSCE?
Seventeen examined stations of nine minutes each, with a minute to read the task before each one. Two preparation stations and at least one rest station bring the circuit to about twenty, and the exam takes about three and a half hours.
What is the pass mark for MRCS Part B?
There is no published pass mark. The cut score is set separately for Applied Knowledge and Applied Skills, for each circuit, by borderline regression. Published pass rates across the 2024/25 diets ranged from 51% to 66%.
Can I fail a station and still pass?
Yes. There is no rule about how many stations you may fail: the cut score applies to your total mark in each component, so a weak station costs the marks you lost on it and strong stations elsewhere can make them back. Applied Knowledge and Applied Skills are passed separately and must both be passed at the same sitting, so a strong anatomy performance cannot rescue a weak communication one.
Dr Richard Miller, MBChB FRCS
Station summaries are reviewed against the current intercollegiate MRCS syllabus and the published marking blueprint. Guidance changes between diets: check the royal colleges' own pages before relying on a date, a fee or a threshold.
Practise this station
The question bank carries the model answer to every question above, with the rest of the applied surgical science and critical care stations.
More applied surgical science and critical care stations