The shocked patient
Shock is not just low BP: it is organs not getting enough blood. Recognise it early, give a fluid challenge, find the type (bleeding, sepsis, heart, blockage, allergy), and treat the cause.
A 48-year-old man is brought in pale, sweaty and confused. Pulse 132, BP 84/50, RR 28, cold hands, capillary refill 5 seconds. His wife says he has had black stools for two days and takes painkiller injections for back pain.
What kind of shock is this, and what do you give first?
- A to E, high-flow oxygenCall for help early.
- Two wide-bore cannulas16G or bigger. Bloods with lactate, group and cross-match.
- Fluid challenge500 mL crystalloid over 15 minutes, then reassess. 250 mL if heart failure is possible.
- Work out the typeCold or warm hands? Neck veins high or low? Bleeding, sepsis, heart, blockage, allergy.
- Bleeding? Blood earlyMajor haemorrhage protocol. Tranexamic acid for trauma within 3 hours.
- MonitorECG, BP every 5 minutes, catheter with hourly urine.
- Treat the causeAntibiotics, source control, stop the bleeding, drain the chest, adrenaline.
- Not respondingSenior and ICU: noradrenaline, more monitoring.
- Systolic BP below 90 or MAP below 65 despite fluids
- Lactate above 4 mmol/L
- Cold, mottled skin, confusion, little urine
- Raised JVP with low BP
- Ongoing bleeding
- Hidden bleeding (GI, ruptured ectopic, AAA, trauma)
- Septic shock
- Cardiogenic shock from MI
- Tension pneumothorax, massive PE or tamponade
- Adrenal crisis
- Wheat pill poisoning
| Fluid challenge | 500 mL over 15 minutes, reassess. Repeat while responding, up to about 2 litres, then senior |
| Heart failure possible | 250 mL boluses |
| Bleeding | Blood early. Do not over-fill with crystalloid |
| Target MAP | 65 mmHg or more. Noradrenaline if not reached with fluid |
| Anaphylaxis | IM adrenaline 0.5 mg first |
Check every dose against a current drug reference and your hospital protocol.
On this page
What shock is
Shock means the organs are not getting enough oxygen, because blood flow is too low. Low BP is a late sign. Young patients and those on beta-blockers may keep a normal BP until they are close to collapse.
- Fast pulse and fast breathing.
- Cold, pale or mottled hands and feet. Capillary refill more than 3 seconds.
- Confusion, agitation, drowsiness.
- Little urine (below 0.5 mL/kg/hour).
- Raised lactate.
- Narrow pulse pressure (for example 100/88).
The four types
- Cold, flat neck veins
- GI bleed, trauma, ectopic, AAA, burns, diarrhoea
- Blood or fluid
- Often warm early, bounding pulse
- Fever, infection, allergen
- Fluid, antibiotics, adrenaline, noradrenaline
- Cold, high neck veins, crackles
- Heart attack, arrhythmia, valve
- Small fluid steps, treat the heart
- Cold, high neck veins, clear lungs
- Tension pneumothorax, massive PE, tamponade
- Decompress, thrombolyse, drain
First hour
- Pulse and BPFalling pulse, rising BP: responding. Continue carefully.
- Capillary refill and skinWarmer, faster refill.
- Mental stateLess confused.
- Urine outputRising.
- LungsNew crackles or falling SpO₂: stop fluid, senior review.
- LactateRepeat within 2 hours. Falling is good.
Bleeding
- Major haemorrhage protocol: red cells early, then plasma, platelets and cryoprecipitate as per protocol.
- Do not flood with crystalloid: it dilutes clotting factors and worsens bleeding. Aim for enough BP to keep the patient perfused (permissive hypotension in trauma, unless head injury).
- Find and stop the source: endoscopy, surgery, interventional radiology, splint the pelvis.
- Keep the patient warm. Cold blood does not clot.
- See Upper GI bleed and Postpartum haemorrhage.
Adrenal crisis
Low BP not responding to fluid, in someone on long-term steroids (or who stopped them suddenly), with low sodium, high potassium or low sugar, vomiting, belly pain. Give hydrocortisone 100 mg IV now. Do not wait for the cortisol result.
Investigations
| Test | Why |
|---|---|
| Blood gas with lactate | Severity, acidosis, potassium, Hb |
| CBC, clotting, fibrinogen | Bleeding, sepsis, DIC |
| Group and cross-match | Blood |
| Urea, creatinine, electrolytes, sugar | Organ damage, adrenal crisis |
| Blood cultures | Sepsis |
| ECG, troponin | Heart attack, arrhythmia |
| Pregnancy test | Ectopic |
| Bedside ultrasound | Free fluid, pericardial effusion, heart function, IVC, AAA |
| Chest X-ray | Pneumothorax, pneumonia, pulmonary oedema |
Common mistakes
- Waiting for the BP to fall before calling it shock.
- Giving 3 litres of saline to a bleeding patient instead of blood.
- Giving litres of fluid to a patient with cardiogenic shock.
- Forgetting a pregnancy test in a young woman in shock.
- Missing adrenal crisis in a patient on long-term steroids.
- Treating the BP number and never finding the cause.
Frequently asked questions
What are the types of shock?
Hypovolaemic (bleeding or fluid loss), distributive (sepsis, anaphylaxis), cardiogenic (heart failure, MI, arrhythmia) and obstructive (tension pneumothorax, massive PE, tamponade).
What is a fluid challenge?
500 mL of crystalloid given over about 15 minutes, followed by reassessment of pulse, BP, perfusion, mental state and urine output. 250 mL is used if heart failure is possible.
When is noradrenaline started in shock?
When the mean arterial pressure stays below 65 mmHg despite adequate fluid, in distributive or cardiogenic shock. It is a senior and ICU decision.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A patient has black stools, pulse 132, BP 84/50 and cold hands. What type of shock is this?
Answer: Hypovolaemic. Melaena with shock: two large cannulas, cross-match, blood early and the upper GI bleed pathway.
- Anaphylactic shock: No trigger.
- Neurogenic shock: No spinal injury.
- Cardiogenic shock: Less likely.
- Septic shock: No infection features.
2. A shocked patient has raised neck veins and absent breath sounds on the left. What type of shock is this?
Answer: Obstructive. Tension pneumothorax causes obstructive shock: decompress immediately.
- Distributive: No.
- Septic: Doesn't explain the chest.
- Cardiogenic from MI: Unilateral absent breath sounds point to pneumothorax.
- Hypovolaemic: Neck veins would be flat.
3. A patient who has taken prednisolone for years is vomiting with BP 80/50, sodium 126 and potassium 5.8. What should be given?
Answer: IV hydrocortisone. Long-term steroid use suppresses the adrenal axis; vomiting can trigger adrenal crisis.
- Furosemide: Harmful.
- Noradrenaline alone: Adrenal crisis needs steroids.
- Insulin: Not indicated.
- Fludrocortisone tablets: Too slow.
4. After an extensive anterior MI, a patient has BP 75/45, cold peripheries, confusion, oliguria and pulmonary crackles. What is the key definitive management?
Answer: Urgent PCI. Cardiogenic shock (commonly from large MI): hypotension with hypoperfusion (cold, oliguria, confusion, raised lactate) and congestion. Early revascularisation (PCI of the culprit lesion) improves survival. Support with inotropes (dobutamine) and vasopressors (noradrenaline), oxygen/ventilation, mechanical circulatory support in selected cases. Exclude mechanical complications (VSD, papillary rupture) with echo.
- 2 L crystalloid bolus: Fluids worsen pulmonary oedema.
- IV metoprolol: Metoprolol is negatively inotropic.
- Oral isosorbide: Isosorbide causes hypotension.
5. In septic shock unresponsive to fluids, which vasopressor is first-line?
Answer: Noradrenaline. Noradrenaline (α1 > β1) is first-line in septic and vasodilatory shock. Vasopressin is added to reduce noradrenaline dose. Adrenaline for anaphylaxis/cardiac arrest and as an alternative. Dobutamine (β1 inotrope) for low cardiac output (cardiogenic shock, septic cardiomyopathy) once MAP is adequate. Dopamine is associated with more arrhythmias.
- Dopamine: Dopamine causes more arrhythmias.
- Isoprenaline: Isoprenaline is a vasodilator.
- Dobutamine alone: Dobutamine is an inotrope that may lower BP.
6. Ventricular preload is best represented by which measurement?
Answer: LV end-diastolic volume. Preload is the stretch on ventricular muscle before it contracts, best measured as end-diastolic volume (or pressure). It depends mainly on venous return. By the Frank–Starling law, greater preload increases stroke volume up to a point.
- Mean arterial blood pressure: An index of afterload.
- Systemic vascular resistance: Determines afterload.
- Stroke volume per beat: The result of contraction, not preload.
- Aortic diastolic pressure: Related to afterload.
7. Which finding best distinguishes early anaphylactic shock from hypovolaemic shock?
Answer: Warm, flushed skin with low SVR. Anaphylactic shock is distributive: histamine and other mediators dilate vessels, so systemic vascular resistance falls and skin is warm and flushed, often with urticaria, wheeze and angioedema. Hypovolaemic shock causes vasoconstriction: high SVR, cold clammy skin. Both cause tachycardia, hypotension, oliguria and raised lactate.
- Tachycardia above 100/min: Present in both.
- Systolic BP below 90 mmHg: Present in both.
- Urine output below 0.5 mL/kg/h: Present in both.
- Raised blood lactate level: Present in both.
References and dose sources
- NICE CG174: Intravenous fluid therapy in adults in hospital
- Surviving Sepsis Campaign adult guidelines 2021
- Resuscitation Council UK guidelines
- Resuscitation Council UK
- NICE NG253 — suspected sepsis in over 16s
- Resus Council — anaphylaxis
- NICE NG158 — VTE
- Ringer's lactate (Hartmann's solution) dosing: Drugs.com: Lactated Ringer's dosage (see also our ringer's lactate (hartmann's solution) dose page)
- Tranexamic acid dosing: Drugs.com: Tranexamic acid dosage (see also our tranexamic acid dose page)
- Noradrenaline (norepinephrine) dosing: Drugs.com: Norepinephrine dosage (see also our noradrenaline (norepinephrine) dose page)
- Hydrocortisone dosing: Drugs.com: Hydrocortisone dosage (see also our hydrocortisone dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.