cardiopulmonary resuscitation (CPR)

Introduction

An emergency measure to maintain a person's breathing & heartbeat when they have stopped as a result of myocardial infarction, trauma, or other disorder. Ventricular arrhythmias are responsible for the majority of cardiopulmonary arrests in adults.

Epidemiology

• see in-hospital cardiopulmonary resuscitation

Clinical manifestations

• 40% of cardiac arrest survivors claim recall of events during cardiac arrest
• gasping during CPR after cardiac arrest is associated with increased 1-year survival with good neurologic outcome
  • do NOT terminate chest compressions prematurely

Diagnostic procedures

• one time electroencephalography (EEG)* for patients who do not follow commands after return to spontaneous circulation

Complications

• pulmonary aspiration & aspiration pneumonia resulting from bag-mask ventilation & endotracheal intubation
• seizures

Management

• priorities:
  • recognition of cardiopulmonary arrest
  • activation of the emergency medical system (EMS)
  • basic life support (see basic life support)
  • defibrillation*
    • restoration normal effective rhythm as soon as possible the single most important goal of resuscitation
    • more basic life support prior to defibrillation does not improve outcomes
    • after initial defibrillation, an additional 2 minutes of chest compression with rescue breathing should follow initial defibrillation before reananalyzing rhythm & checking for pulse*
    • public access defibrillation (PAD) improves return of spontaneous circulation & survival after out-of-hospital cardiac arrest
      • only a minority of patients sustain spontaneous circulation after defibrillation; but still favorable neurologic outcomes (37.7% vs 22.6%) & survival (44% vs 32%) are improved by defibrillation
    • defibrillation for ventricular fibrillation & other shockable rhythms prior to administration of epinephrine in in-hospital cardiac arrest
  • airway
    • intubation
      • attempts at endotracheal intubation can interrupt chest compressions &/or slow defibrillation
    • bag mask ventilation vs endotracheal intubation for out-of-hospital cardiac arrest
      • results of comparison inconclusive
    • the AHA no longer recommends blind finger sweeping of airway under any circumstances, as this may push foreign objects into the airway & cause an obstruction*
  • large bore peripheral IV for fluid resuscitation
    • preferably 2 large bore IV lines
    • administration of appropriate IV medications
  • non-shockable rhythms
    • a novel technigue involves an airway adjunct impedance threshold device & active compression-decompression with a device resembling a toilet plunger
    • combined with automated gradual head-up/torso-up positioning
    • improves cerebral blood flow impeded by increased intracranial pressure resulting from standard supine CPR
• also see pediatric basic & advanced cardiopulmonary life support
• hypothermia may (or may not) preserve brain function
  • for initial rhythms of
    • ventricular tachycardia/ventricular fibrillation
    • asystole/pulseless electrical activity
  • procedures include
    • therapeutic hypthermia (32-34 degrees C for 24 hours)
      • all adults who do not follow commands after return to spontaneous circulation
      • a target temperature of 31 C does not reduce mortality or improve neurologic outcome at 180 days vs a target temperature of 34 C
      • fever prevention (<= 37.5 C) more important than cooling to a lower temperature
        • target temperature = 32-37.5 C
      • for patients initially hypothermic after return to spontaneous circulation, rewarm no faster than 0.5 C/hour
    • slightly lowering temperature then slowly warming, holding below 37.5 degrees C for 72 hours
  • mild therapeutic hypothermia for neuroprotection after CPR of benefit
  • prehospital cooling not recommened
  • no benefit in neurological outcomes or mortality for maintenance of mild hypothermia for out-of-hospital cardiac arrest
• epinephrine
  • early epinephrine associated with better survival outcomes in adults with shockable & nonshockable out-of-hospital cardiac arrest
  • epinephrine administered by paramedics associated with improved 30 day survival in out-of-hospital cardiac arrest (3.2% vs 2.4%); survivors more likely to have severe neurologic disability
• consider a therapeutic trial of a nonsedating anticonvulsant in patients with EEG evidence of ictal or interictal waveforms
• extracorporeal membrane oxygenation (ECMO)
  • may be appropriate in select patients in qualified health care settings
• special considerations for patients with ventricular assist device or artificial heart

* pneumomic ABC for Airway, Breathing, Circulation seems no longer recommended

* the same logic would seem to apply to rescue breathing as applies to blind finger sweep; both would seem to risk pushing a foreign object further into the airway, whereas compression- only CPR would not (ref does not seem to consider this)

Prognosis:

• cardiopulmonary resuscitation at the site of cardiac arrest with better ourcomes than immediate transport & resuscitation attempts on the way to the hospital
• factors predicting neurologically intact survival include age, renal insufficiency (serum creatinine > 2.0 mg/dL), hypotension, myocardial infarction, frailty
• the most sensitive early (48 hours) markers of poor outcome (no sedation) are:
  • no pupillary response or corneal response
  • absence of motor response to pain
  • burst suppression pattern on electroencephalogram
• mortality, brain damage, & nursing home admission at 1 year lower if bystanders had jumped in to help in out-of-hospital cardiac arrest
• criteria for unsurvivable out-of-hospital cardiac arrest
  • cardiac arrest unwitnessed by emergency medical services or medical personnel
  • nonshockable initial rhythm
  • lack of return of spontaneous circulation before receipt of a third dose of 1-mg epinephrine
• survival of in-hospital cardiac arrest to hospital discharge with good congitive outcome in elderly (70 years) is > 15%
• frail patients are unlikely to survive to hospital discharge following in-hospital cardiac arrest

Notes

• often performed poorly
• when performed properly, delivers only a small fraction of normal cardiac output
• chest-compression-only out-of-hospital bystander CPR at least as effective as standard CPR
• uninterrupted chest compressions in out-of-hospital cardiac arrest improves outcomes
  • quality of compressions more important than continuous vs interrupted
• compression-only CPR is associated with higher rates of bystander CPR, which boosts the overall survival rate
  • standard CPR is associated with the highest survival rate
• CPR-trained bystanders may give rescue breaths between chest compressions (ratio 30:2)
• emergency medical services should provide positive pressure ventilation in addition to chest compressions until supraglottic device or endotracheal tube is established
• conventional cardiopulmonary resuscitation better than compression-only CPR for children with noncardiac causes of arrest
• suction cup device used by emergency medical services personnel may improve survival
• CPR is more efficient with use of two devices:
  • a chest-wall suction device that allows active decompression as well as compression of the chest
  • an airway impedance-threshold device that limits passive ventilation during chest decompression
  • ResQCPR System FDA-approved for use by first responders
• mechanical CPR does not improve survival over manual CPR in adults with out-of-hospital cardiac arrest
• giving family members the choice to observe out-of-hospital cardiopulmonary resuscitation is associated with better psychological outcomes
• telephone guidance for bystanders improved CPR performance & survival in Arizona
• return of spontaneous circulation in out-pf-hospital cardiac arrest lower during the COVID-19 pandemic

In 1998, paramedics implemented a new guideline that allows emergency personnel to withhold resuscitation if a patient has a terminal condition & the patient, a family member, or a caregiver has indicated (verbally or in writing) that the patient did not want resuscitation.

Dispatcher assistance increases use of bystander CPR in children & improves neurologic outcomes

bystander CPR before arrival of emergency medical services arrival more than doubles 30-day survival

automated external defibrillators in public places improves outcomes

fully autonomous drones equipped with a global positioning system & autopilot software could be used to speed delivery of automated external defibrillators to bystanders during an episode of sudden cardiac arrest

More general terms

• clinical procedure

More specific terms

• advanced cardiac life support (ACLS)
• basic life support (BLS)
• CPR class 1 intervention
• CPR class 2 intervention
• CPR class 3 intervention
• in-hospital cardiopulmonary resuscitation (CPR)
• termination of cardiopulmonary resuscitation (CPR)

Additional terms

• cardiac arrest
• emergency medical system (EMS)
• outcomes of comatose patients after cardiopulmonary resuscitation (CPR)