Shock Assessment OSCE — Four Types, ABCDE Approach, and Fluid Resuscitation

Why Shock Assessment Is Examined

Shock is a state of cellular hypoperfusion leading to organ dysfunction and death. It is the underlying mechanism in many acute medical and surgical emergencies. OSCEs examine it as: a deteriorating patient scenario (BP 80/50 on the ward — what do you do?), an interpretation station (what type of shock is this?), or a prescribing station (write a fluid resuscitation plan). Examiners test systematic assessment, type differentiation, and the evidence-based treatment of each category.

The Four Types of Shock

Differentiating Types Clinically

Haemorrhagic Shock Classification (ATLS)

ABCDE Assessment of the Shocked Patient

A — Airway

Secure airway — unconscious patients (GCS below 8) need anaesthetic review and intubation.

B — Breathing

• High-flow oxygen (15 L/min non-rebreathe mask) in all shocked patients
• Assess for tension pneumothorax (absent breath sounds, tracheal deviation, raised JVP — needle decompression immediately)
• SpO2, respiratory rate, chest examination

C — Circulation

• Heart rate, BP (lying and sitting), capillary refill time, skin temperature, JVP, urine output
• IV access x2 large-bore; bloods (FBC, U&E, LFTs, lactate, blood cultures, clotting, crossmatch)
• 12-lead ECG (ischaemia, arrhythmia)
• Fluid challenge: 500 mL Hartmann's or 0.9% NaCl over 15 minutes — reassess after each bolus
• Catheterise for hourly urine output monitoring (target 0.5 mL/kg/hour)

D — Disability

• GCS, pupils, blood glucose (hypoglycaemia mimics and complicates shock)

E — Exposure and Everything Else

• Full exposure looking for bleeding sources, rashes (anaphylaxis, meningococcal sepsis), pericardial rub
• Temperature (sepsis, hypothermia)
• Consider imaging: CXR (haemothorax, widened mediastinum), POCUS (pericardial effusion, IVC size)

Fluid Resuscitation — Evidence-Based Approach

Fluid choice:

• Crystalloids (Hartmann's or 0.9% NaCl) — first-line for all types of shock
• Blood products (1:1:1 ratio: PRBC:FFP:platelets) — for haemorrhagic shock (massive transfusion protocol)
• Albumin has no mortality benefit over crystalloids in sepsis
• Avoid colloids (HES/starch) — associated with increased AKI and mortality

Fluid challenge vs fluid resuscitation:

• Bolus 250-500 mL over 10-15 minutes
• Assess response: HR, BP, capillary refill, urine output
• Repeat if responsive — stop if no improvement after 2 boluses (seek senior help)

Vasopressors — When Fluids Are Not Enough

Vasopressors require HDU/ITU — discuss with senior before initiation.

Septic Shock Management — Surviving Sepsis Bundle

Frequently Asked Questions

"What is the difference between shock and hypotension?"

Hypotension is defined as systolic BP below 90 mmHg (or more than 40 mmHg below baseline). Shock is a broader clinical syndrome of inadequate tissue perfusion — it can occur before hypotension develops (compensated shock) and is characterised by tachycardia, peripheral vasoconstriction, reduced urine output, and rising lactate. Conversely, hypotension can occur without shock (e.g., postural hypotension on standing in an otherwise well patient).

"What is obstructive shock and how do you treat it?"

Obstructive shock results from mechanical obstruction to cardiac filling or outflow. The three main causes are: tension pneumothorax (treat with immediate needle decompression second intercostal space, midclavicular line, then chest drain), cardiac tamponade (treat with pericardiocentesis — drain the pericardial effusion), and massive pulmonary embolism (treat with systemic thrombolysis or surgical embolectomy). All three are immediately reversible if recognised and treated promptly.

"What does a raised lactate indicate?"

Lactic acidosis in shock results from anaerobic metabolism — cells switch to anaerobic glycolysis when oxygen delivery is insufficient, producing lactate as a by-product. Lactate above 2 mmol/L indicates tissue hypoperfusion; above 4 mmol/L is associated with significantly increased mortality. A falling lactate in response to treatment is a useful marker of resuscitation adequacy. However, lactate can also be elevated without tissue hypoperfusion (liver failure, thiamine deficiency, Metformin, sepsis-independent mechanisms).

"What is POCUS and how is it used in shock assessment?"

Point-of-care ultrasound is bedside ultrasound performed at the time of assessment. In shock, it is used for: IVC collapsibility index (estimates volume status — a collapsible IVC suggests hypovolaemia), cardiac function assessment (global LV function, RV dilation suggesting PE), pericardial effusion (tamponade), pleural fluid or haemothorax, and free fluid in the abdomen (haemoperitoneum in trauma). FAST (Focused Assessment with Sonography in Trauma) is a standardised POCUS protocol used in trauma.

"When do you call ITU in a shocked patient?"

Immediate ITU referral is required for: shock not responding to initial resuscitation (2 fluid boluses without improvement), septic shock requiring vasopressors, cardiogenic shock, obstructive shock not immediately reversible, lactate above 4 mmol/L despite treatment, or any organ dysfunction (AKI, impaired consciousness, respiratory failure). The decision to escalate should be made early — do not wait for the patient to deteriorate further before calling for help.

Related Posts

• Sepsis and NEWS Score OSCE — systematic approach to the septic patient
• Anaphylaxis Management OSCE — distributive shock in anaphylaxis
• Basic Life Support OSCE — managing the patient in cardiac arrest from any cause