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Level 2 of 6Must-remember

Cardiac arrest and advanced life support

Assess, manage and stay safe — enough on its own

The card — assess, manage, caution

Assessment— look, ask, measure

  • Diagnose in ten seconds on two findings: the patient is unresponsive and is not breathing normally. Nothing else is required, and nothing else may delay the first compression.
  • A pulse check adds information only if a confident examiner completes it inside those same ten seconds: even experienced clinicians are unreliable at palpating a pulse under stress, and every second without compressions is a second of zero cerebral perfusion.
  • Agonal breathing is the great trap: slow, noisy, irregular gasping or snoring respirations are a sign of cardiac arrest, not a sign of life. If you have to ask whether that is breathing, the answer is no — more arrests are missed this way than any other.
  • A brief convulsion or a few myoclonic jerks at the moment of collapse is common and reflects abrupt cerebral hypoperfusion; it regularly gets the arrest labelled as epilepsy. Pupils dilate and become unreactive within about a minute, which carries no prognostic meaning and never justifies withholding resuscitation.
  • There are only four arrest rhythms in two groups: shockable — ventricular fibrillation and pulseless ventricular tachycardia; non-shockable — asystole and pulseless electrical activity. Only about 20–25% of contemporary arrests present in VF, but that group is the most likely to survive and the most time-critical.Not available at your setup — Defibrillator.
  • Fine VF closely mimics asystole: before calling a near-flat trace asystole, check the lead connections, turn up the gain and look in a second lead — and if in any doubt, shock.Doctor / NurseNot available at your setup — Defibrillator.
  • Return of spontaneous circulation means an organised rhythm WITH a palpable central pulse, a measurable blood pressure, or a sudden sustained rise in end-tidal carbon dioxide. An organised complex on the monitor without any of those is pulseless electrical activity, not ROSC.
  • End-tidal carbon dioxide is the only continuously available measure of CPR quality: during good CPR it runs at 1.3–2.7 kPa (10–20 mmHg), a falling value within a cycle means the compressor is tiring, and a value persistently below about 1.3 kPa (10 mmHg) after 20 minutes of high-quality CPR in an intubated patient indicates a very poor prognosis.Not available at your setup — Endotracheal intubation kit.
  • The highest-yield test during an arrest is a blood gas — potassium, calcium, pH, lactate, glucose and haemoglobin within minutes — remembering that metabolic abnormalities may be a consequence of the arrest rather than its cause.Not available at your setup — Arterial blood gas.
  • Hunt the reversible causes in every cycle — the four Hs and four Ts: hypoxia; hypovolaemia; hypo- and hyperkalaemia and other metabolic derangement; hypothermia; thrombosis (coronary and pulmonary); tension pneumothorax; tamponade; toxins.
  • Recognise the peri-arrest patient before the arrest: threatened airway or stridor; respiratory rate ≥ 25 or < 8 per minute; SpO2 below 90% on supplemental oxygen; systolic BP below 90 mmHg or a fall > 40 mmHg from baseline; heart rate below 40 or above 130 per minute; urine output below 0.5 mL/kg/h; new confusion or a fall in Glasgow Coma Scale of 2 points or more; lactate above 2 mmol/L with hypoperfusion.
  • In children the equivalents are different: a heart rate below 60 per minute with poor perfusion, grunting, capillary refill beyond 4 seconds, a child too lethargic to protest at a cannula, and a parent's statement that the child is not behaving normally. An infant or child with a heart rate below 60 per minute and signs of poor perfusion is in arrest for practical purposes and requires chest compressions.
  • Population changes the picture: in the elderly arrest follows hours of nonspecific decline and the rhythm is more often PEA or asystole; in-hospital arrest is preceded by hours of documented physiological abnormality, of which a rising respiratory rate is the earliest and most consistently abnormal; paediatric arrest is hypoxic until proved otherwise; beyond about 20 weeks of pregnancy aortocaval compression means supine compressions generate almost no output; in trauma the mechanism is exsanguination, tension pneumothorax or tamponade.
  • In severe hypothermia the patient may appear dead — rigid, apnoeic, impalpable pulse, fixed pupils — while remaining entirely salvageable. Prolonged palpation and rhythm assessment are justified here and almost nowhere else.
  • Record the Utstein variables, because they carry most of the prognostic weight: whether the arrest was witnessed, whether bystander CPR was given, the initial rhythm, the interval from collapse to first compression, and the interval from collapse to first shock.
  • Check a capillary glucose and a core temperature in every arrest, and after ROSC obtain a 12-lead ECG immediately — ST elevation mandates urgent revascularisation, and about 70% of resuscitated arrest survivors without ST elevation still have relevant coronary disease.

Management— do this, in order

  • Start compressions immediately — supine on a firm surface, heel of one hand over the centre of the chest (lower half of the sternum), second hand on top with fingers interlocked and lifted off the ribs, arms straight, shoulders over the hands. Depth 5–6 cm, rate 100–120 per minute, complete recoil, 30 compressions to 2 ventilations, and change the compressor every 2 minutes at each rhythm check.
  • Ventilate with a bag–valve–mask and reservoir at 15 L/min oxygen, two-handed with a second operator squeezing the bag, and an oropharyngeal airway sized from the incisors to the angle of the jaw; each breath over about one second with just enough volume to make the chest visibly rise.
  • Vascular access: a large peripheral cannula in the antecubital fossa first; after two failed attempts or two minutes, place an intraosseous needle (proximal tibia or humerus in adults) — every drug and fluid here may be given by that route at the same dose. After every peripheral or intraosseous drug, flush with 20 mL of 0.9% sodium chloride and elevate the limb for 10–20 seconds.Doctor / Nurse
  • Shockable rhythm — shock at once. Pads: one below the right clavicle to the right of the sternum, the other in the left mid-axillary line at about the level of V6. Energy 150 J for the first biphasic shock, then 150–200 J for every subsequent shock (200 J throughout is equally acceptable); if only a monophasic defibrillator is available, use 360 J for every shock. Charge during compressions and keep the pre-shock pause under five seconds.Doctor / NurseNot available at your setup — Defibrillator.
  • After the shock, resume compressions immediately for 2 minutes without checking the pulse or the rhythm — the only exception is an unmistakable sustained sign of life such as purposeful movement, coughing or normal breathing.
  • Shockable drug timing is precise: after the third shock give adrenaline 1 mg IV/IO and amiodarone 300 mg IV/IO; then adrenaline 1 mg every 3–5 minutes; after the fifth shock a further amiodarone 150 mg. If amiodarone is unavailable, lidocaine 1 mg/kg (about 100 mg in an adult) with a further 50 mg after the fifth shock — never give both.Doctor / Nurse
  • In a witnessed, monitored arrest with a defibrillator already attached, up to three stacked shocks may be given in rapid succession before compressions begin, after which the standard cycles resume.Doctor / NurseNot available at your setup — Defibrillator.
  • Refractory VF: move the pads to an anteroposterior position (left precordium and between the scapulae), confirm adhesion and dry skin, give magnesium sulfate 2 g (8 mmol) IV over 10–15 minutes if torsades de pointes, hypomagnesaemia or digoxin toxicity is suspected, and re-work the reversible causes.Doctor / NurseNot available at your setup — Defibrillator.
  • Non-shockable rhythm — do not shock. Give adrenaline 1 mg IV/IO immediately, as soon as access is achieved, then every 3–5 minutes, and spend the whole of every cycle working through the reversible causes, because in asystole and PEA the treatment is the cause.Doctor / Nurse
  • Airway: a bag–valve–mask with an oropharyngeal airway is an acceptable airway for a whole arrest, and a supraglottic airway is the sensible middle route. Intubation is for the operator who can pass the tube in at most five seconds. Once any advanced airway is in place, abandon the 30:2 cycle: continuous compressions at 100–120/min with 10 breaths per minute, asynchronously.Doctor / NurseNot available at your setup — Endotracheal intubation kit. A bag-valve-mask with an oropharyngeal airway, or a supraglottic airway, is acceptable for the whole arrest.
  • Hyperkalaemia: calcium chloride 10%, 10 mL IV (or calcium gluconate 10%, 30 mL); sodium bicarbonate 8.4%, 50 mmol IV; 10 units of soluble insulin in 50 mL of 50% glucose IV; dialysis after ROSC. Hypokalaemia or hypomagnesaemia: cautious potassium replacement and magnesium sulfate 2 g (8 mmol) IV.Doctor / NurseNot available at your setup — Serum electrolytes.
  • Hypovolaemia: rapid crystalloid bolus of 500 mL, and blood for haemorrhage pushed by hand or pressure device since gravity will not deliver during CPR. Tension pneumothorax: immediate needle decompression or finger thoracostomy on clinical grounds, then a drain — do not wait for a radiograph. Tamponade: pericardiocentesis, or resuscitative thoracotomy in penetrating trauma with a witnessed arrest.Doctor / NurseNot available at your setup — Blood & blood products, Chest drain / tube thoracostomy.
  • Hypothermia: below 30°C withhold resuscitation drugs and limit defibrillation to three shocks; above 30°C double the drug intervals until normothermia. Continue CPR until the core temperature is at least 32°C, using warmed fluids, humidified oxygen and extracorporeal rewarming where available.Doctor / Nurse
  • Toxins: opioid — naloxone 0.4–2 mg IV, repeated; tricyclic or other sodium-channel blocker — sodium bicarbonate 8.4%, 50–100 mmol IV; beta-blocker — glucagon 5–10 mg IV; calcium-channel blocker — calcium chloride 10%, 10 mL IV with high-dose insulin euglycaemia; digoxin — correct potassium and magnesium and give digoxin-specific antibody fragments; local anaesthetic — lipid emulsion 20%; organophosphate — escalating atropine plus pralidoxime. Resuscitate far longer than usual.Doctor / Nurse
  • Pulmonary embolism: thrombolysis for PEA arrest with strongly suspected massive embolism, and if it is given, continue CPR for 60–90 minutes before considering stopping. Coronary thrombosis: urgent angiography and revascularisation. Acidaemia: effective ventilation, not routine bicarbonate — if metabolic acidosis persists after successful defibrillation with adequate ventilation, sodium bicarbonate 1 mmol/kg may be given.Doctor / Nurse
  • Special circumstances. Anaphylaxis: use the arrest dose of adrenaline (1 mg IV), not the 0.5 mg intramuscular dose, and give large-volume crystalloid rapidly, since up to 35% of the circulating blood volume can extravasate within 10 minutes. Severe asthma: ventilate slowly at low rates and volumes, disconnect the circuit briefly to let the chest deflate, hunt bilateral tension pneumothorax, consider magnesium sulfate 2 g IV. Drowning and paediatric arrest: 5 rescue breaths before compressions. Electrocution: isolate the source before touching the patient.Doctor / Nurse
  • Pregnancy beyond about 20 weeks: manually displace the uterus to the patient's left (or wedge 15–30 degrees left lateral), compress slightly higher on the sternum, anticipate a difficult airway, and if there is no ROSC within about 4 minutes, perform perimortem caesarean delivery — for the mother's benefit as much as the infant's.Doctor / Nurse
  • Paediatric: estimate weight for ages 1–10 years as (age in years + 4) × 2 kg; 5 rescue breaths first; compress the lower half of the sternum to about 4 cm in an infant under 1 year (two-thumb encircling technique) and about 5 cm in a child, ratio 15:2 with two or more rescuers, defibrillate at 4 J/kg for every shock, adrenaline 10 microgram/kg IV/IO = 0.1 mL/kg of 1:10,000, maximum 1 mg, amiodarone 5 mg/kg (max 300 mg), fluid 10 mL/kg. Newborn resuscitation uses a ratio of 3:1, delivering 90 compressions and 30 breaths per minute. Check the blood glucose in the first minute of every collapsed child.Doctor / NurseNot available at your setup — Defibrillator.
  • After ROSC, treat the first ten minutes as more dangerous than the arrest — pads stay on, drugs stay drawn up. Targets: SpO2 94–98%; PaCO2 4.5–6.0 kPa (35–45 mmHg); mean arterial pressure ≥ 65 mmHg; glucose 6–10 mmol/L (108–180 mg/dL); a constant temperature between 32°C and 37.5°C for 24–72 hours with fever actively prevented; potassium about 4.5 mmol/L and magnesium about 2.0 mmol/L.Not available at your setup — Arterial blood gas.
  • Post-ROSC haemodynamics: intubate and ventilate anyone who does not obey commands; treat hypotension first with a 500 mL crystalloid bolus, then noradrenaline by infusion from about 0.05 microgram/kg/min (roughly 3–4 microgram/min in a 70 kg adult) titrated to MAP ≥ 65 mmHg, adding dobutamine 2.5–10 microgram/kg/min if output remains poor after adequate filling.Doctor / NurseNot available at your setup — Endotracheal intubation kit, Mechanical ventilator, Infusion pump.

Caution— what harms

  • Never let a pulse check delay compressions, and never accept the absence of a felt pulse as the only thing you were waiting for — the diagnosis is unresponsive plus not breathing normally.
  • Never treat agonal gasps, a brief seizure at collapse, or dilated unreactive pupils as evidence of life or of futility.
  • Never check a pulse or the rhythm immediately after a shock. Mechanical output rarely returns at once because the myocardium is stunned and must be perfused; this is the most frequently broken rule in real arrests.
  • Hyperventilation is harmful and is a stress reflex that must be actively suppressed: excessive rate or volume raises mean intrathoracic pressure, impedes venous return, reduces coronary perfusion pressure and worsens survival.
  • Leaning on the chest abolishes recoil without the operator noticing, and coronary perfusion pressure collapses to zero the instant compressions stop — every pause resets the myocardium, so charge the defibrillator during compressions and keep the pre-shock pause under five seconds.
  • Do not shock asystole; it achieves nothing except an interruption to compressions and myocardial injury. Atropine is no longer given routinely in asystole or PEA.Doctor / NurseNot available at your setup — Defibrillator.
  • Never give amiodarone and lidocaine together, and never give 1:1000 adrenaline intravenously to a child — the paediatric dose is 10 microgram/kg, that is 0.1 mL/kg of 1:10,000.Doctor / Nurse
  • Never attribute an arrest to an electrolyte result unless the context supports it — metabolic abnormalities are frequently a consequence of the arrest rather than its cause.
  • Never use cardiac standstill on echocardiography as the sole criterion for stopping, and never use a composite post-ROSC score such as CAHP or OHCA alone to withdraw treatment.Not available at your setup — Ultrasound.
  • Move any free-flowing oxygen source at least a metre from the chest before shocking: defibrillation with oxygen at the chest has caused fires, as well as skin burns.
  • Unrecognised oesophageal intubation is uniformly fatal, which is why waveform capnography is not optional once a tube is placed; if the first intubation attempt fails, revert to a mask or supraglottic device rather than making repeated attempts on an uncompressed patient.Doctor / NurseNot available at your setup — Endotracheal intubation kit.
  • Stop the 100% oxygen once a reliable saturation is available — hyperoxaemia aggravates reperfusion injury — and do not hyperventilate to a low PaCO2, which causes cerebral vasoconstriction.
  • Do not prognosticate early. Functional neurological assessment is deferred until at least 72 hours after return to normothermia, typically four to five days after the arrest, and no single test suffices; premature pessimism produces a self-fulfilling prophecy.
  • Do not stop too soon in the salvageable groups: resuscitate substantially longer than usual in hypothermia, poisoning, pregnancy, drowning, electrocution, and for 60–90 minutes after thrombolysis for suspected pulmonary embolism. Nobody is dead until they are warm and dead.
  • Do not give anticonvulsants prophylactically after ROSC; treat clinical seizures, and remember that post-hypoxic myoclonus may respond to clonazepam 1.5–10 mg daily orally or valproate 300–1200 mg daily in divided doses.Doctor / Nurse

Refer / escalate

Call the arrest team and a critical care bed at the moment of recognition, not after the first cycle; escalate to cardiology for immediate coronary angiography where there is ST elevation after ROSC or a shockable initial rhythm, to obstetrics for perimortem caesarean if there is no ROSC within about 4 minutes beyond 20 weeks of pregnancy, and to a centre offering extracorporeal support for refractory arrest, hypothermic arrest or massive pulmonary embolism — and where the situation is genuinely unclear, start, because a resuscitation can be stopped and a life cannot be restarted.

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