3.5 Practice Drills and Readiness Markers

Post-ROSC (Post-Cardiac Arrest) Care

Return of spontaneous circulation is the start of a new, fragile phase, not the end of the resuscitation. The post-cardiac-arrest bundle protects the brain, heart, and other organs from secondary injury. Drive these targets:

Airway and breathing. If not already intubated, secure an advanced airway and confirm with waveform capnography. Ventilate to a normal ETCO2 - hyperventilation lowers cerebral blood flow and raises intrathoracic pressure, both harmful. Titrate oxygen down to maintain SpO2 94-99%, because hyperoxia generates injurious free radicals.

Circulation. Hypotension worsens anoxic brain injury, so support a SBP above 90 mmHg / MAP above 65 mmHg with fluids and, if needed, a vasopressor infusion (norepinephrine, epinephrine, or dopamine).

Disability and the 12-lead. Obtain a 12-lead ECG immediately; if it shows STEMI, the patient needs emergent coronary angiography. Comatose patients (not following commands) are candidates for targeted temperature management, maintaining a constant temperature between 32 C and 36 C and then actively preventing fever for at least 24-72 hours.

Avoiding secondary injury

The two great post-ROSC mistakes are over-oxygenating and over-ventilating. Hyperoxia (an oxygen saturation pinned at 100% on high-flow oxygen) increases oxidative free-radical injury, so titrate FiO2 down to keep SpO2 in the 94-99% range. Hyperventilation is harmful in two ways: it raises intrathoracic pressure and impedes venous return (lowering cardiac output), and by blowing off carbon dioxide it constricts cerebral vessels and reduces cerebral blood flow at the worst possible time.

Ventilate to a normal rate (about 10 breaths per minute) targeting an ETCO2 near 35-40 mmHg. Re-arrest is common in the first minutes after ROSC, so keep the defibrillator on the patient, reassess the rhythm and pulse frequently, and continue any antiarrhythmic infusion that was started during the code.

Matching the special situation to its fix

The unifying skill across special resuscitations is recognizing the modifier early and adding the targeted therapy without abandoning high-quality CPR. A renal-failure patient who arrests with a widening QRS and a peaked-T history points to hyperkalemia - calcium to protect the myocardium is the time-critical move. A young patient with a long QT collapsing into polymorphic VT points to torsades - magnesium.

A pregnant patient past mid-gestation needs manual left uterine displacement to relieve aortocaval compression so compressions actually generate output, and the clock on a perimortem cesarean starts at arrest. A cold-water-immersion victim may look dead but is profoundly hypothermic - rewarm before declaring death, because cold-protected brains have recovered after long downtimes.

An overdose patient in true arrest still needs compressions and ventilation first; naloxone reverses the respiratory depression that caused the arrest but is not a substitute for CPR. In every case, the standard algorithm runs underneath the specific antidote.

Special Resuscitation Situations

Several scenarios change the standard algorithm. Recognizing the modifier is a favorite exam target.

• Torsades de pointes (polymorphic VT with a long QT): give magnesium sulfate 1-2 g IV/IO; if pulseless, defibrillate.
• Hyperkalemia-induced arrest (peaked T waves, widening QRS, history of renal failure): give calcium chloride/gluconate to stabilize the myocardium plus sodium bicarbonate and other measures to shift potassium.
• Suspected massive pulmonary embolism (a T in the H's and T's): thrombolytics may be given during CPR per protocol.
• Cardiac arrest in pregnancy (after ~20 weeks): apply manual left uterine displacement to relieve aortocaval compression, use standard drug doses and energy, and prepare for possible perimortem cesarean.
• Severe hypothermia: start CPR, limit drugs/shocks until the core is rewarmed, and remember the maxim that the patient is not dead until warm and dead - prolonged resuscitation is justified.
• Opioid-associated arrest: prioritize high-quality CPR and ventilation; naloxone addresses the respiratory cause but does not replace compressions in a true arrest.

Readiness drill

Build a two-column drill: on the left, a rhythm or scenario (refractory VF, symptomatic bradycardia in complete block, stable narrow SVT, inferior STEMI, post-ROSC hypotension, torsades, opioid arrest); on the right, the exact next action and dose. You are ready when you can, after a day away, name the action and the number - epinephrine 1 mg q3-5 min, atropine 1 mg to a max of 3 mg, adenosine 6 then 12 mg, amiodarone 300 then 150 mg, magnesium 1-2 g - without looking, and can explain why each distractor fails.

Mixed-practice retention

Readiness in this domain is not the same as having read the algorithms once. The reliable marker is mixed practice that stays stable after a one-day break: pull random scenarios that span arrest and peri-arrest, force yourself to state the rhythm, the stability assessment, and the next action with its dose, then justify why two distractors are wrong. Trace repeated misses to a specific cue - did you misjudge stability, forget the dose, choose the wrong electrical therapy, or skip the reversible-cause search?

Logging the miss by category (stability error, dose error, sequence error, electricity-versus-drug error) turns a vague weakness into a fixable pattern. When your scores hold steady across a day off and you can defend your reasoning aloud, the domain is exam-ready.