If >20 mmol/L, hyperglycemic emergency consideration
Blood gas
pH
PaCO2 mmHg
PaO2 mmHg
Lactate mmol/L
Electrolytes
Potassium mmol/L for arrhythmia triggers
Ionized calcium mmol/L for myocardial function
Magnesium mmol/L for torsades risk
Etiology and organ injury evaluation
Etiology-directed labs
High-sensitivity troponin for suspected ACS
Interpret in clinical context post-arrest
CBC for anemia or infection
Coagulation studies for bleeding risk and thrombolysis planning
Creatinine and urea for renal impairment and dosing
AST ALT for hypoxic hepatitis
CK for rhabdomyolysis context
Pregnancy test in reproductive potential
Toxicology targeted testing
Acetaminophen level if overdose concern
Salicylate level if overdose concern
Carboxyhemoglobin if CO exposure concern
Ethanol if relevant
Interpretation pearls and pitfalls
Lab interpretation considerations
Lactate elevation from low-flow state and epinephrine
Troponin elevation from global ischemia without coronary occlusion
Metabolic acidosis from arrest duration and perfusion failure
Hyperkalemia from acidosis or missed dialysis
Hemolysis artifact falsely elevating potassium
Diagnostic Tests
Scoring Systems
Clinical scales and structured reporting
Neurologic status scales
GCS for initial status
FOUR score when intubated
Utstein-style reporting elements
Witnessed status
Bystander CPR
Initial rhythm
Time to first shock
Time to ROSC
Post-arrest prognostication caution
Avoid early definitive prognostication in first 72 hours after ROSC when sedated or cooled
MRI
MRI brain applications
Hypoxic-ischemic injury assessment
Diffusion-weighted imaging patterns
Timing typically >48-72 hours post-ROSC for prognostication support
Alternative diagnoses
Acute ischemic stroke
Encephalitis
Practical constraints
Hemodynamic instability limiting transport
Device compatibility for pacemaker or ICD
CT
CT imaging strategy
CT head non-contrast
Intracranial hemorrhage suspicion
Unexplained coma after ROSC
CT pulmonary angiography
Suspected massive PE
RV strain signs or high pretest probability
CT aorta
Suspected dissection or rupture
CT chest
Aspiration
Pneumothorax
Imaging timing considerations
Minimize delay to coronary angiography when STEMI present
Ultrasound (or US)
POCUS in cardiac arrest
Cardiac views during pulse checks only
Pericardial effusion and tamponade physiology
RV dilation for PE suspicion
Cardiac standstill documentation as prognostic adjunct
Lung ultrasound
Pneumothorax assessment
Pulmonary edema patterns
IVC assessment as volume status adjunct
Technique safeguards
If ultrasound prolongs pause, abort scan and resume compressions
Single-cycle image capture for later review
Disposition
Post-arrest level of care
Destination and monitoring level
ICU admission for all comatose post-ROSC patients
ICU admission for hemodynamic or respiratory instability
Cath lab activation pathway
STEMI on ECG
High suspicion coronary occlusion with shockable rhythm and no clear non-cardiac cause
Transfer criteria
Targeted temperature management capability needed
Coronary angiography capability needed
ECPR capability needed
Termination and post-mortem pathways
Termination and post-mortem considerations
Local termination of resuscitation protocol adherence
Medical examiner or coroner notification triggers
Organ donation referral where appropriate
Family support and communication pathway
Documentation for death certification as applicable
Treatment
ACLS core algorithm
Core cardiac arrest management
High-quality CPR
Minimal interruptions
Compressor switch every 2 minutes
Defibrillation strategy for shockable rhythms
Biphasic 120-200 J initial if unknown device default
Escalate energy for subsequent shocks
Epinephrine timing
Non-shockable
Initiate epinephrine as soon as feasible
Shockable
Initiate epinephrine after initial defibrillation attempts and ongoing CPR
Antiarrhythmic use for refractory VF or pVT
Amiodarone or lidocaine options
Medication protocols
Medication dosing and sequences
Epinephrine IV/IO 1 mg
Repeat every 3-5 minutes
Class I recommendation for cardiac arrest (AHA)
Amiodarone IV/IO for refractory VF or pVT
300 mg bolus
Additional 150 mg bolus if needed
Class IIb recommendation for refractory VF or pVT (AHA)
Lidocaine IV/IO alternative for refractory VF or pVT
1.0-1.5 mg/kg bolus
Additional 0.5-0.75 mg/kg bolus
Maximum 3 mg/kg total
Class IIb recommendation for refractory VF or pVT (AHA)
Magnesium sulfate IV for torsades
2 g bolus
Repeat once if refractory
Class IIa recommendation for torsades (AHA)
Sodium bicarbonate IV
1 mmol/kg for specific indications
Tricyclic antidepressant toxicity
Hyperkalemia with ECG changes
Severe metabolic acidosis with prolonged arrest and specific guidance
Routine use not recommended (Class III no benefit, AHA)
Calcium chloride IV for specific indications
10 mL of 10% solution
Hyperkalemia with ECG changes
Calcium channel blocker overdose
Hypocalcemia
Dextrose for hypoglycemia
If glucose <3.0 mmol/L, dextrose IV per local concentration and protocol
Reversible cause directed therapies
Cause-specific interventions
Tension pneumothorax
Immediate needle decompression or finger thoracostomy if trained
Chest tube placement
Cardiac tamponade
Pericardiocentesis if tamponade physiology and arrest
Massive PE
Systemic thrombolysis consideration during arrest when high suspicion and no contraindication
Opioid toxicity
Naloxone pathway if respiratory arrest suspected and pulses present
Prioritize ventilation and oxygenation if pulseless
Hypothermia
Active rewarming
Prolonged resuscitation consideration until rewarmed in severe hypothermia
Post-ROSC management
Post-ROSC hemodynamics and neuroprotection
Fluids and vasopressors
Norepinephrine infusion if shock
Initiate 0.05-0.1 mcg/kg/min
Titrate every 2-5 minutes to MAP ≥65 mmHg
Sedation and analgesia if intubated
Avoid hypotension from oversedation
Targeted temperature management
Temperature control strategy for comatose survivors
Prevent fever
Seizure management
Benzodiazepine for convulsive seizure
Continuous EEG when available for refractory coma or suspected nonconvulsive seizures
Coronary reperfusion therapy
Emergent angiography for STEMI (Class I, AHA)
Consider early angiography for shockable rhythm with suspected cardiac cause (Class IIa, AHA)
Airway confirmation and ventilation safety
Airway and ventilation safety checks
Continuous waveform capnography for intubated patients
Tube confirmation
CPR quality feedback
ROSC detection adjunct
ACEP evidence grading label
Level B or C depending on local policy
Ventilation strategy post-ROSC
Avoid hyperventilation
Avoid severe hypocapnia
SpO2 94-98%
Special Populations
Pregnancy
Pregnancy-specific cardiac arrest modifications
Manual left uterine displacement
High-quality CPR with standard hand position
Defibrillation energy same as nonpregnant
Airway early due to aspiration risk and rapid desaturation
Perimortem cesarean delivery consideration
If fundus at or above umbilicus
If no ROSC by 4 minutes, delivery by 5 minutes goal when feasible
Reversible causes emphasis
Hemorrhage
Eclampsia
Amniotic fluid embolism
Pulmonary embolism
Geriatric
Older adult considerations
Higher baseline coronary disease prevalence
Medication burden and QT risk
Frailty affecting prognosis and goals of care discussions
Rib fractures and CPR injury risk
Lower physiologic reserve post-ROSC
Pediatrics
Pediatric cardiac arrest approach
Respiratory etiology predominance
PALS algorithm pathway
Compression depth
One-third of AP chest diameter
Defibrillation for VF or pVT
2 J/kg first shock
4 J/kg subsequent shocks
Maximum 10 J/kg or adult maximum
Epinephrine IV/IO 0.01 mg/kg
0.1 mL/kg of 0.1 mg/mL solution
Repeat every 3-5 minutes
Amiodarone IV/IO for refractory VF or pVT
5 mg/kg bolus
Maximum 300 mg per dose
Hs and Ts adapted
Hypoxia
Hypovolemia
Hypothermia
Toxins
Tamponade
Tension pneumothorax
Thrombosis
Pulmonary
Coronary
Weight-based dosing reference requirement
Use length-based tape when weight unknown
Background
Epidemiology
Epidemiologic features
Out-of-hospital cardiac arrest incidence higher than in-hospital
Shockable rhythms proportion higher in witnessed adult arrests
Survival strongly dependent on early CPR and early defibrillation
Neurologic outcome related to no-flow and low-flow times
Pathophysiology
Pathophysiologic sequence
Abrupt loss of effective cardiac output
Global ischemia
Myocardium
Brain
Kidneys
Reperfusion injury after ROSC
Oxidative stress
Inflammation
Post-cardiac arrest syndrome
Brain injury
Myocardial dysfunction
Systemic ischemia reperfusion response
Persistent precipitating pathology
Therapeutic Considerations
Rationale for key therapies
CPR generates limited forward flow
Compression fraction and depth critical
Defibrillation treats VF and pVT by terminating disorganized electrical activity
Epinephrine increases coronary perfusion pressure via alpha-adrenergic vasoconstriction
Antiarrhythmics support defibrillation success in refractory VF or pVT
Temperature control reduces fever-associated secondary brain injury
Coronary reperfusion addresses common precipitant in adult shockable arrests
Avoid hyperoxia and hypocapnia to reduce secondary neurologic injury
Early goals-of-care integration for high-burden comorbidity and poor prognosis scenarios
Patient Discharge Instructions
copy discharge instructions
copy discharge instructions
If discharged after recovery from cardiac arrest
Follow-up within 7 days with cardiology or primary care
Medication list review and adherence plan
Driving restriction counseling per local law and cardiology advice
Avoid alcohol and recreational drugs until cleared
Return immediately for chest pain
Return immediately for dyspnea
Return immediately for palpitations or syncope
Return immediately for new weakness or speech difficulty
Return immediately for seizure activity
Wound care instructions for defibrillation pads or lines if present
Family CPR and AED education resources recommendation
References
Clinical guidelines and consensus
Resuscitation guideline sources
American Heart Association Guidelines for CPR and Emergency Cardiovascular Care
Adult Basic Life Support and Advanced Cardiovascular Life Support sections
Pediatric Advanced Life Support sections
Evidence grading using Class of Recommendation and Level of Evidence
International Liaison Committee on Resuscitation Consensus on Science with Treatment Recommendations
European Resuscitation Council Guidelines
Evidence-based sources and tools
Supporting evidence and implementation resources
Utstein reporting templates for cardiac arrest registries
Post-cardiac arrest syndrome reviews and critical care pathways
Capnography standards for airway confirmation and CPR quality monitoring
POCUS guidance for cardiac arrest with pulse-check time minimization
ACEP evidence grading system
Level A randomized evidence
Level B moderate evidence
Level C consensus or limited evidence
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.