Shock and vasoactive support

Recognise shock early from perfusion, not just blood pressure; classify it with bedside tools and POCUS; give fluids only to responders; choose and titrate vasopressors and inotropes correctly; manage cardiogenic shock; and use lactate and capillary refill as resuscitation targets.

6 topics

01
Recognising and classifying shock
Shock is inadequate tissue perfusion, often but not always with hypotension. Look at the three windows (skin, kidney, brain) and lactate, then use history, examination and POCUS to sort it into hypovolaemic, distributive, cardiogenic or obstructive.
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02
Fluid challenge and fluid responsiveness
Give fluid only if the patient is likely to respond and needs more cardiac output. Use passive leg raise or a mini fluid challenge with a cardiac output surrogate, and stop when the response is lost or harm appears.
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03
Vasopressors: choice, titration and escalation
Noradrenaline is first-line. Target MAP 65 mmHg (60-65 in septic patients aged ≥ 65). Add vasopressin as noradrenaline doses escalate (commonly 0.25-0.5 mcg/kg/min), then adrenaline; consider steroids and look for a missed cause in refractory shock.
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04
Inotropes and inodilators
Use an inotrope only when low cardiac output causes hypoperfusion despite adequate filling and MAP. Dobutamine is the usual first choice; milrinone or levosimendan suit beta-blocked or RV-failure patients.
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05
Cardiogenic shock
Stage it (SCAI A-E), find the cause (usually acute MI), revascularise the culprit lesion early, support with noradrenaline ± inotrope, and involve a shock team early for mechanical support in selected patients.
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06
Lactate, capillary refill and resuscitation targets
Lactate is a marker of severity and response, not only of tissue hypoxia. Re-measure every 2 h during resuscitation; capillary refill time is a fast, non-inferior target. Know the non-hypoxic causes of raised lactate.
5 stepsAlgorithmNew

Drugs in this module

Doses written for this module's context. The same drug may read differently in another module.

Noradrenaline (norepinephrine)

Catecholamine vasopressor (alpha-1 > beta-1)

Indications: First-line vasopressor for septic, vasodilatory and most cardiogenic shock with hypotension.
Adult dose: Start 0.05-0.1 mcg/kg/min; titrate every 5-10 min to MAP 65 mmHg (60-65 if septic and aged ≥ 65). Usual 0.05-0.5 mcg/kg/min. Add vasopressin as doses escalate (commonly 0.25-0.5 mcg/kg/min). > 0.5-1 mcg/kg/min = refractory shock.
Preparation (India): 2 mg/2 mL ampoules. Standard syringe 4 mg in 50 mL NS or D5 (80 mcg/mL); 8 mg in 50 mL (160 mcg/mL) if fluid-restricted.
Cautions: Extravasation necrosis (phentolamine 5-10 mg in 10 mL NS infiltrated if available). Digital and mesenteric ischaemia at high dose. May start via a good proximal peripheral cannula while central access is placed.
Monitoring: Arterial line, MAP, lactate, capillary refill, urine output; hourly peripheral site checks.

Vasopressin

V1 agonist (non-catecholamine vasopressor)

Indications: Second vasopressor in vasodilatory/septic shock; may help in RV failure and pulmonary hypertension because it does not raise pulmonary vascular resistance much.
Adult dose: Fixed 0.03 units/min (0.01-0.04). Not titrated like noradrenaline.
Preparation (India): 20 units/mL ampoules. 20 units in 50 mL NS = 0.4 units/mL; 0.03 units/min = 4.5 mL/h.
Cautions: Digital, mesenteric and myocardial ischaemia; hyponatraemia. Avoid as sole agent in low cardiac output.

Adrenaline (epinephrine)

Catecholamine (beta-1, beta-2, alpha-1)

Indications: Second or third agent in refractory vasodilatory shock; cardiogenic shock with hypotension (short term); anaphylaxis.
Adult dose: Infusion 0.05-0.5 mcg/kg/min. Anaphylaxis: 0.5 mg IM (0.5 mL of 1 mg/mL) every 5 min as needed.
Preparation (India): 1 mg/mL ampoules. 4 mg in 50 mL = 80 mcg/mL.
Cautions: Raises lactate via beta-2 glycolysis; tachyarrhythmia; hyperglycaemia; more refractory shock than noradrenaline in infarct-related cardiogenic shock (OptimaCC).

Phenylephrine

Pure alpha-1 agonist

Indications: Short-term bolus for anaesthesia-related vasodilatation; hypotension with tachyarrhythmia; LVOT obstruction (HOCM, SAM).
Adult dose: Bolus 50-100 mcg IV; infusion 0.5-2 mcg/kg/min (or 20-200 mcg/min).
Preparation (India): 10 mg/mL ampoules. Bolus syringe: 10 mg in 100 mL (100 mcg/mL).
Cautions: Reflex bradycardia; reduces cardiac output if LV function is poor. Not a first-line agent in septic shock.

Dopamine

Catecholamine (dose-dependent DA, beta-1, alpha-1)

Indications: Rarely: bradycardic hypotension where pacing is unavailable. Not recommended as first-line in shock.
Adult dose: 5-20 mcg/kg/min.
Preparation (India): 200 mg/5 mL ampoules. 200 mg in 50 mL = 4000 mcg/mL.
Cautions: More arrhythmias than noradrenaline, and higher mortality in cardiogenic shock (SOAP II subgroup). 'Renal-dose' dopamine has no benefit.

Dobutamine

Inotrope (beta-1 > beta-2)

Indications: Low cardiac output with hypoperfusion despite adequate filling and MAP (cardiogenic shock, septic cardiomyopathy).
Adult dose: 2.5-10 mcg/kg/min (max 20).
Preparation (India): 250 mg/20 mL vials. 250 mg in 50 mL = 5000 mcg/mL.
Cautions: Vasodilatation and hypotension (support MAP with noradrenaline first); tachyarrhythmia; increases myocardial O2 demand.

Milrinone

Phosphodiesterase-3 inhibitor (inodilator)

Indications: Low-output states, especially with high pulmonary vascular resistance, RV failure, or beta-blocker therapy.
Adult dose: 0.125-0.75 mcg/kg/min infusion; usually omit the loading dose (50 mcg/kg over 10 min) because of hypotension.
Preparation (India): 10 mg/10 mL ampoules. 10 mg in 50 mL = 200 mcg/mL.
Renal / hepatic: Renally cleared: reduce dose in AKI (e.g. max 0.2-0.4 mcg/kg/min when eGFR < 30) and expect a long half-life.
Cautions: Hypotension, arrhythmia; accumulates in renal failure.

Levosimendan

Calcium sensitiser and K-ATP opener (inodilator)

Indications: Low-output heart failure, especially in patients on beta-blockers; weaning from inotropes (specialist use).
Adult dose: 0.05-0.2 mcg/kg/min for 24 h; omit the 6-12 mcg/kg bolus if hypotensive.
Preparation (India): 12.5 mg/5 mL vials. 12.5 mg in 500 mL D5 = 25 mcg/mL.
Cautions: Hypotension; active metabolite lasts about 1 week. Not recommended for septic shock (LeoPARDS). Not for septic shock: SSC 2026 suggests against levosimendan there.

6 topics

Recognising and classifying shock

Fluid challenge and fluid responsiveness

Vasopressors: choice, titration and escalation

Inotropes and inodilators

Cardiogenic shock

Lactate, capillary refill and resuscitation targets

Drugs in this module

Module references (19)