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Level 2 of 6Must-remember

Shock: recognition and resuscitation

Assess, manage and stay safe — enough on its own

The card — assess, manage, caution

Assessment— look, ask, measure

  • What you are looking for: shock is acute circulatory failure with inadequate or inappropriately distributed tissue perfusion causing generalised cellular hypoxia — a diagnosis of perfusion, not of blood pressure.
  • History to ask for: fever, cough or any source of infection; vomiting, diarrhoea, black stool or visible bleeding; chest pain, breathlessness or palpitation; a sting, drug, food or new medicine; trauma; last menstrual period in any woman of childbearing age; steroids taken or recently stopped; and all regular drugs, especially beta-blockers, calcium channel blockers, digoxin, anticoagulants and antihypertensives.
  • Blood pressure and its traps: hypotension is conventionally a systolic below 90 mmHg or a mean arterial pressure below 60–65 mmHg, but a chronic hypertensive may be profoundly shocked at 130/80 mmHg while a patient with autonomic failure or cirrhosis lives comfortably at 85/50 mmHg — judge against the patient's own baseline and follow the trend.
  • The brain window: new confusion, agitation, drowsiness or a falling Glasgow Coma Scale means compensation has already been outstripped — this is decompensated shock.
  • The kidney window: with previously normal renal function, urine output below 0.5 mL/kg per hour indicates shock; in children the threshold is below 1 mL/kg per hour and below 2 mL/kg per hour in infants.
  • The skin window: cold, pale, clammy, slate-grey peripheries with capillary refill over 3 seconds in an adult or over 2 seconds in a child; mottling ascends from the knee, so palpate the knee and not only the fingers.
  • Respiratory rate: a quietly rising respiratory rate is the earliest and most frequently ignored sign, driven by the metabolic acidosis — count it for a full minute.
  • Heart rate can lie: its absence does not exclude shock, because beta-blockers, calcium channel blockers, digoxin, conduction disease, athletic conditioning and neurogenic shock all blunt it, and extreme hypovolaemia may be accompanied by bradycardia.
  • Pulse pressure is free information: a wide pulse pressure with a low diastolic and warm peripheries indicates a high-output distributive state, while a narrow thready pulse with cold peripheries indicates a low-output state.
  • Three bedside questions sort almost every case: are the peripheries warm or cold; are the neck veins raised or flat; is the chest wet or dry? Cold with raised veins and a clear chest is obstructive shock — the group with the shortest time to collapse.
  • Bedside numbers to record: capillary glucose, lactate, shock index (heart rate divided by systolic pressure; normal 0.5–0.7, above 0.9 abnormal), and qSOFA — one point each for systolic below 100 mmHg, respiratory rate above 22 per minute and altered mentation with GCS below 15, two or more being positive.Not available at your setup — Arterial blood gas. Shock index and qSOFA need only pulse, blood pressure, respiratory rate and mentation — record them even where glucose and lactate testing are unavailable.
  • Lactate: a value above 2 mmol/L defines both septic and cardiogenic shock, above 5 mmol/L predicts death in infarct-related cardiogenic shock and above 8 mmol/L defines SCAI stage E — repeat at 2 and at 6 hours, because serial values beat any single value.Not available at your setup — Arterial blood gas.
  • Immediately lethal, specifically treatable causes to seek on the first pass: absent breath sounds with hyper-resonance and tracheal deviation (tension pneumothorax); raised jugular venous pressure with muffled heart sounds and pulsus paradoxus (tamponade); urticaria, wheeze or angio-oedema after an exposure (anaphylaxis); inferior ST-elevation with raised JVP, clear lungs and hypotension (right ventricular infarction); sudden hypotension with a clear chest, hypoxia and right heart strain (massive pulmonary embolism); a non-blanching rash (meningococcal sepsis); and hypotension unresponsive to fluid and vasopressors with hyponatraemia and hypoglycaemia (adrenal crisis).
  • How much blood has been lost: blood pressure may be maintained despite a 25% reduction in circulating volume in a young fit patient, although unreplaced losses exceeding 15% eventually produce hypotension — a normal pressure never excludes major haemorrhage.
  • Children compensate far longer and then crash: hypotension in a child is a pre-terminal sign, defined as a systolic below 70 mmHg in infants under 1 year, below 70 plus twice the age in years between 1 and 10 years, and below 90 mmHg over 10 years — hunt instead for central capillary refill over 2 seconds, tachycardia for age, cool mottled peripheries with an ascending temperature gradient, weak peripheral with strong central pulses, tachypnoea without distress, and irritability progressing to lethargy; bradycardia in a shocked child is a pre-arrest rhythm.
  • Groups whose presentation is blunted: in the elderly the clues are mild confusion, tachycardia, tachypnoea, falling urine output, rising creatinine and new glucose intolerance, often without fever — a temperature below 36°C marks severity, not reassurance; the immunosuppressed and neutropenic may mount neither fever nor leucocytosis; pregnancy masks haemorrhage; spinal cord injury gives warm peripheries with hypotension and bradycardia; and chronic liver disease lowers the baseline so the usual thresholds under-diagnose shock.

Management— do this, in order

  • Treat and diagnose at the same time: oxygen, access, fluid, cultures, antibiotics and the ECG all proceed while the cause remains unknown — treatment must never be delayed while the final diagnosis is established.
  • Oxygen: give supplemental oxygen and titrate to an SpO₂ of 92–95%.
  • Access: place two peripheral cannulae of 16 or 18 gauge, since a short wide peripheral cannula delivers fluid faster than a long triple-lumen central line; where peripheral access fails in a peri-arrest patient, intraosseous access is the quickest route to the central circulation and accepts every drug and fluid listed here.Doctor / Nurse
  • Monitoring: catheterise every shocked patient for hourly urine measurement, attach continuous cardiac monitoring and pulse oximetry, and record a 12-lead ECG and capillary glucose.
  • Choose the fluid: crystalloid, preferring a balanced solution (Ringer's lactate or Hartmann's) where large volumes are anticipated; 0.9% sodium chloride is an acceptable alternative but large volumes cause hyperchloraemic acidosis, and hydroxyethyl starch must not be used in critically ill patients.
  • Septic or distributive shock: work towards 30 mL/kg in the first hour (about 2 L in a 70 kg adult) given as 500 mL aliquots with reassessment after each; children 10–20 mL/kg over 10–20 minutes, reassessed after every bolus.
  • Non-haemorrhagic hypovolaemia: 500 mL boluses titrated to clinical endpoints; children 10–20 mL/kg over 10–20 minutes.
  • Haemorrhagic shock: give blood, not crystalloid — crystalloid is a bridge only; children packed red cells 10 mL/kg, warmed. Where the patient is not actively bleeding the transfusion threshold is a haemoglobin below 70 g/L, and a target of 90 g/L may be more appropriate in significant coronary artery disease or limited respiratory reserve.Not available at your setup — Blood & blood products. While blood is being obtained, use crystalloid as a bridge only, control the bleeding, and transfer urgently to a facility with blood.
  • Cardiogenic shock: 250 mL challenges only, and only without fluid overload, auscultating the chest after each; in massive pulmonary embolism give 500 mL of 0.9% sodium chloride and then stop, because further volume worsens a failing right ventricle; where volume status is uncertain a 250 mL crystalloid challenge (or 10 mL/kg) will usually show whether the hypotension is fluid-responsive.
  • Reassess the same five things after every bolus: pulse and blood pressure; capillary refill and peripheral temperature; respiratory rate and oxygen requirement; the lung bases for new crackles; and mental state. Stop and reconsider when new basal crackles appear, the oxygen requirement rises, the JVP becomes visibly raised, or the pressure has not improved after 30 mL/kg — and in children, if shock persists after 40 mL/kg consider elective intubation rather than further boluses.
  • Noradrenaline is the first-line vasopressor in septic, other distributive, cardiogenic and pulmonary-embolism-related shock: start 4–8 microgram/min IV (about 0.05–0.1 microgram/kg/min) and titrate every 5 minutes to a MAP of at least 65 mmHg; refractory shock may need 10–30 microgram/min, and children 0.05–0.1 microgram/kg/min. Where hypotension is severe do not wait until 30 mL/kg has been given before starting it.Doctor / NurseNot available at your setup — Infusion pump.
  • Anaphylaxis: remove the trigger and give adrenaline 500 microgram (0.5 mL of 1:1000) intramuscularly into the anterolateral thigh, repeated every 5 minutes if there is no improvement; children 10 microgram/kg IM — 150 microgram under 6 years, 300 microgram at 6–12 years, 500 microgram over 12 years — with generous intravenous crystalloid, and antihistamine and corticosteroid as adjuncts, never substitutes.
  • Cardiogenic shock drugs: dobutamine 2.5–10 microgram/kg/min IV (occasionally to 20) is the first-line inotrope, combined with noradrenaline in mixed shock; children 2.5–10 microgram/kg/min. For refractory hypotension add adrenaline by infusion, starting 1 microgram/min IV with a usual range of 1–10 microgram/min (children 0.05–0.3 microgram/kg/min).Doctor / NurseNot available at your setup — Infusion pump.
  • Antibiotics: give broad-spectrum empirical antibiotics within one hour of recognising septic shock, after cultures where these can be taken promptly — inability to obtain cultures must not delay treatment. Paediatric first-hour cover is ceftriaxone 80 mg/kg IV once daily or cefotaxime 50 mg/kg IV 6-hourly; in neonates under 28 days use cefotaxime plus amoxicillin or ampicillin. In severe invasive group A streptococcal infection add clindamycin 900 mg IV 8-hourly to benzylpenicillin 2.4 g IV 4-hourly. Drain the source.Doctor / NurseNot available at your setup — Blood culture. Inability to obtain cultures must not delay treatment — give the antibiotics without them.
  • Steroid: in suspected adrenal crisis give hydrocortisone 100 mg IV immediately with fluid and glucose (children 2 mg/kg IV, maximum 100 mg) and do not wait for a cortisol result; in septic shock with an ongoing vasopressor requirement give hydrocortisone 50 mg IV 6-hourly (200 mg/day).Doctor / Nurse
  • Mechanical emergencies: tension pneumothorax needs immediate needle decompression before any imaging and then an intercostal drain; tamponade needs fluid to maintain filling then pericardiocentesis or surgical drainage; haemorrhage needs the bleeding controlled — endoscopy, surgery or interventional radiology.DoctorNot available at your setup — Chest drain / tube thoracostomy.
  • Arrhythmia causing shock — treat the rhythm: for bradycardia with hypotension give atropine 500 microgram IV every 3–5 minutes to a maximum of 3 mg (children 20 microgram/kg, minimum 100 microgram, maximum 600 microgram), with isoprenaline 20–60 microgram IV bolus then 2–20 microgram/min or transvenous pacing if refractory; for tachycardia with shock, syncope, ischaemia or heart failure give urgent synchronised cardioversion at 100–200 J for ventricular tachycardia.DoctorNot available at your setup — Defibrillator.
  • Massive transfusion — more than 8–10 units of red cells in 24 hours, loss of 50% or more of blood volume within 3 hours, or blood loss exceeding 150 mL/min — is given with fresh frozen plasma and platelets in a balanced 1:1:1 ratio; warm the blood and the patient, and correct hypocalcaemia with 10% calcium chloride 10 mL IV or 10% calcium gluconate 10 mL IV over 5 minutes.Doctor / NurseNot available at your setup — Blood & blood products.

Caution— what harms

  • Never diagnose shock by the blood pressure alone: readings above 90 mmHg systolic do not exclude it and readings below do not by themselves define it — and hypotension in a child is a pre-terminal, not an early, sign.
  • Never give nitrates or diuretics in right ventricular infarction, and avoid nitrates when the systolic pressure is below 90 mmHg; in right ventricular infarction give fluid instead.
  • Do not use hydroxyethyl starch in critically ill patients — it increases the risk of acute kidney injury and has been associated with increased mortality.
  • Do not chase the acidosis with bicarbonate as a reflex: it generates carbon dioxide that worsens intracellular acidosis, causes sodium overload, shifts the oxyhaemoglobin curve leftward and lowers ionised calcium. Consider it only in severe metabolic acidaemia with pH at or below 7.2 in the presence of acute kidney injury — except in sodium-channel-blocker poisoning, where sodium bicarbonate 50–100 mmol IV is specific therapy.
  • Dopamine 5–20 microgram/kg/min is a second choice only: it offers no survival benefit, causes more arrhythmias in all-cause shock, increases mortality in the cardiogenic subgroup and has no role as a first-line agent in distributive shock.
  • A vasopressor into an empty circulation is a squeeze on nothing: optimise volume first, and correct what stops the drugs working — hypoxaemia, hypocalcaemia and severe acidosis impair contractility, as do beta-blockers, antiarrhythmics and sedatives; hypotension, hypoglycaemia, hypercalcaemia, hypoxia, hypercapnia and hyperthermia must all be corrected rapidly.
  • Falsely reassuring signs: pulse oximetry is unreliable when the peripheries are cold and shut down, so believe the blood gas; a normal haemoglobin does not exclude acute haemorrhage before haemodilution; and a normal pressure with tachycardia in a young adult, athlete or pregnant woman precedes an abrupt decompensation.
  • Never attribute an unexplained tachycardia or raised lactate to anxiety in a patient who looks unwell.
  • Fluid is a drug with a toxicity: pulmonary and peripheral oedema develop readily in critically ill patients given large volumes; take particular care in severe acute malnutrition and in diabetic ketoacidosis, where over-rapid fluid is associated with cerebral oedema, and in children reconsider the plan rather than repeat boluses beyond 40 mL/kg.
  • Anticipate hypotension during and after endotracheal intubation: many shocked patients are fluid-responsive, so give volume before induction and prepare a vasopressor; ventilate with lung-protective settings (tidal volume at or below 6 mL/kg predicted body weight, plateau pressure at or below 30 cmH₂O). There are few data supporting non-invasive ventilation in shock.DoctorNot available at your setup — Endotracheal intubation kit, Mechanical ventilator.
  • Catecholamine harms: all inotropes increase myocardial oxygen consumption and may extend an infarct, and peripheral vasopressor infusion causes extravasation injury — central administration is preferred.
  • In envenoming, tourniquets, incision and suction devices are harmful, and releasing a field ligature may precipitate hypotension or dysrhythmia as stagnant acidotic blood carrying venom re-enters the circulation; vasopressors are considered only after aggressive volume resuscitation and antivenom, since the patient may be reacting anaphylactically to the venom or the antivenom.
  • Never let cultures delay antibiotics, and never continue antibiotics once sepsis has been excluded — all antibiotics should then be stopped.
  • When shock will not respond, the answer is almost always one of five things: bleeding not yet found (retroperitoneum, pelvis, long-bone fracture, gastrointestinal tract, ruptured ectopic pregnancy); an undrained source of infection; a wrong diagnosis (tamponade, tension pneumothorax, pulmonary embolism, adrenal crisis, poisoning); an uncorrected metabolic derangement (acidosis, hypocalcaemia, hypoxia, hypoglycaemia); or an infusion that is not actually running because the cannula is tissued, the line disconnected or the bag empty.

Refer / escalate

Call for help and arrange transfer at once for any shock persisting after adequate volume resuscitation, any obstructive cause needing a procedure (tension pneumothorax, tamponade, massive pulmonary embolism), infarct-related cardiogenic shock needing percutaneous coronary intervention or thrombolysis, uncontrolled haemorrhage needing surgery or endoscopy, or a shocked child — and target admission to intensive care within 6 hours of initial stabilisation for any patient who is critically ill or in shock.

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