CARDIAC ARREST

CARDIAC ARREST - Bobby Peters, MD, FAAEM
BASICS
DESCRIPTION
• Absence of effective mechanical cardiac activity
• This section is not a substitute for an American Heart Association-approved Advanced Cardiac Life Support (ACLS) course and is intended only as a quick reference.
• Synonym(s): Code Blue
ALERT
Geriatric Considerations
Poor risk for survival and long-term outcome
Pediatric Considerations
Bradycardia is the most common initial form of cardiac arrest. Most frequently, it is a response to underlying pulmonary disease and hypoxia. Adequate oxygenation and ventilation are especially important.
Pregnancy Considerations
• Displace the uterus either manually or by placing a rolled towel or pad under the right hip. If the patient cannot be resuscitated within 5-15 minutes, consider emergency C-section to relieve uterine obstruction and increase blood return to the heart. This may also be done to save the fetus if at a viable age.
• Consider amniotic fluid embolism or eclampsia-related seizures as precipitating factors.
GENERAL PREVENTION
Treat underlying disease
EPIDEMIOLOGY
• Predominant age: Increases with age
• Predominant sex: Male > Female
Prevalence
In the United States: 200:100,000 (per year)
RISK FACTORS
• Male gender
• Increasing age
• Hypercholesterolemia
• Hypertension
• Cigarette smoking
• Family history of atherosclerosis
• Diabetes
ETIOLOGY
• Asystole (confirm in two leads; 11% actually fine ventricular fibrillation [VF])
• VF
• Pulseless ventricular tachycardia (VT)
• Pulseless electrical activity (PEA, previously known as electrical mechanical dissociation [EMD])
ASSOCIATED CONDITIONS
• Coronary artery disease (cardiac arrest may be first presenting symptom)
• Valvular heart disease
• Hypertension


DIAGNOSIS
SIGNS AND SYMPTOMS
• Loss of consciousness secondary to central nervous system hypoperfusion
• Absence of pulses in large arteries
• Apnea or agonal breathing
• Cyanosis or pallor
History
Find out how patient coded
• Witness or unwitnessed?
• Seizure activity?
• History or risk factors?
Physical Exam
• Check pupils: Dilated may indicate drug overdose
• Check pulse, hydration status, diaphoretic? (i.e., reasons for tachycardia)
• Check lungs (i.e., did person have respiratory decline before cardiac decline?)
TESTS
ECG
Lab
• Arterial blood gases
• Electrolytes
• CBC
• Drug levels (check toxicology screen, Tylenol level, also digoxin level or antiepileptic levels of history of specific medication use, etc.)
• Prothrombin time (international normalized ratio), partial thromboplastin time, type, and cross, if indicated
• Lab results may be altered by
- Digoxin toxicity: May cause hyperkalemia
- Hypo- or hyperventilation: Changes oxygen partial pressure and carbon dioxide partial pressure
- Acidosis: Increases serum potassium
Imaging
Chest radiograph for endotracheal tube (ET) placement, pneumothorax; consider echocardiogram for pericardial effusion
Diagnostic Procedures/Surgery
• If PEA secondary to tamponade, may need paracardiocentesis
• If coding, probably needs airway intubation
• May need central line for IV access
• May need chest tube for pneumothorax
Pathological Findings
Based on underlying cause
DIFFERENTIAL DIAGNOSIS
• Adverse reaction to drugs: Barbiturates, narcotics, calcium channel blockers, beta-blockers, and tricyclic antidepressants
• Shock: Septic or blood-loss induced
• Hypothermia
• Pulmonary embolism
• Cardiac tamponade
• Pneumothorax
• Acidosis
• Electrolyte abnormality
• Carbon monoxide poisoning
TREATMENT
STABILIZATION
• Prehospital emergency medical service personnel, ED, "cardiac arrest team," intensive care setting
• If response time is >5 minutes, improved outcome noted in patients when CPR started before defibrillation in Vfib. (1)[A]
GENERAL MEASURES
• Perform defibrillation 1st
- Adults: 200, 300, or 360 J
- Children: Use largest paddles that will fit on child, even adult size if good contact can be achieved.
- Defibrillate at 2 J/kg once. Increase to 4 J/kg twice.
• Administer 100% oxygen by bag-valve-mask or ET (preferred)
• Start 2 IV lines as close to the heart as possible (central line okay, but do not waste time). Large-bore peripheral lines can deliver fluid more quickly than a central line, especially important in PEA secondary to hypovolemia.
• Perform CPR, including closed-chest compression. Intermittent abdominal compression and active compression/decompression show no survival advantage.
• Keep patient, especially a child, warm if possible.
• Monitor pulse after 3 initial defibrillations. Check monitor between each defibrillation and after any intervention.
• Use an end-tidal CO2 monitor to assess gas exchange, if available. Esophageal intubation will produce a very low end-tidal CO2 and requires proper reintubation.
MEDICATION (DRUGS)
First Line
• Lidocaine, atropine, naloxone, and epinephrine may all be given by ET. Follow with 10 mL of normal saline or sterile water, followed by bagging.
• Epinephrine: 1 mL = 1 mg (1:1,000); 1 mL = 0.1 mg (1:10,000)
• Adults: VT and pulseless VT. Use in order listed below
- Defibrillate (nonsynchronized setting) 3 times at 200, 300, and 360 J
 Check monitor rhythm.
 Follow each drug administration with repeated defibrillation at 360 J.
 Check monitor and pulses after each subsequent intervention.
• Epinephrine: 1 mg IV every 3-5 minutes or a vasopressin 40 U IV single dose, 1 time only; may choose to resume epinephrine if no response after a single dose of vasopressin (high-dose epinephrine is permissible, but discouraged and may actually worsen outcomes).
• Amiodarone: 300 mg IV push may be used prior to lidocaine
• Lidocaine: 1.5 mg/kg IV, repeat in 5 minutes to total dose of 3 mg/kg
• Magnesium sulfate: 1-2 mg IV in suspected torsades de pointes or refractory VF/VT
• Procainamide: 30 mg per minute IV in refractory VF/VT (maximum dose: 17 mg/kg) is permissible. However, because the time to a useful level by infusion is so long, it is discouraged and is unlikely to be of any benefit. No improvement in survival to discharge.
• Bicarbonate: 1 mEq/kg IV only in known preexisting bicarbonate-responsive acidosis or to alkalinize the urine in known tricyclic overdose
Adults: Asystole
• CPR
• Confirm in 2 leads.
• Consider possible causes, including hypoxia, hyperkalemia, hypokalemia, preexisting acidosis, drug overdose, and hypothermia.
• Consider defibrillation, as for VT/VF, since VF may be mistaken for asystole.
• Consider immediate transcutaneous pacing.
• Epinephrine: 1 mg IV push repeated q3-5min; may use intermediate-dose or high-dose epinephrine (2-5 mg IV or 0.1 mg/kg IV) q3-5min
• Atropine: 1 mg IV push q3-5min to total dose of 0.04 mg/kg; shorter atropine dosing intervals acceptable (q1-2min)
• Consider termination of efforts if no reversible underlying cause is found.
For Pulseless Electrical Activity
• Includes EMD, idioventricular rhythms, ventricular escape rhythms, bradycardic-asystolic rhythms, and postdefibrillation idioventricular rhythms
• Assess blood flow by Doppler ultrasound if available.
• Consider possible reversible causes: Cardiogenic shock (weak pump), cardiac tamponade, tension pneumothorax, severe hypovolemia, pulmonary embolism (consider thrombolytics), hypothermia, hypoxia, acidosis, hyperkalemia, or overdose of drugs such as beta-blockers, calcium channel blockers, tricyclics, and digoxin (pnemonic 5H and 5Ts).
• Epinephrine: 1 mg IV push and repeat q3-5min; may use intermediate-dose or high-dose epinephrine (2-5 mg IV or 0.1 mg/kg IV, respectively) q3-5min, but this shows no proven improvement in survival
• Atropine: 1 mg IV q3-5min to total dose of 0.04 mg/kg if absolute bradycardia (60 beats per minute) or relative bradycardia; may decrease interval to 1-2min if desired
Children (drugs listed in alphabetical order):
• Amiodarone for pulseless VF/VT, 5 mg/kg IV or intraosseous (IO) rapid bolus; for perfusing tachyarrhythmias, loading dose of 5 mg/kg IV or IO over 20-60 minutes, maximum dose 15 mg/kg/d
• Atropine: 0.01-0.02 mg/kg per dose; minimum dose is 0.1 mg, maximum single dose is 0.5 mg in child, 1.0 mg in adolescent
• Epinephrine
- For bradycardia: 0.01 mg/kg IV/IO or 0.1 mg/kg ET (1:1,000)
- For asystolic or pulseless arrest: 1st dose is 0.01 to 0.03 mg/kg IV/IO. Doses as high as 0.2 mg/kg may be effective.
- Infusion: 0.1 ug/kg per minute. Titrate to desired effect (0.1-1.0 ug/kg per minute).
• Lidocaine:
- Bolus: 1 mg/kg per dose (maximum 3 mg/kg)
- Infusion: 20-50 ug/kg per minute
• Sodium bicarbonate: 1 mEq/kg per dose or 0.3  kg  base deficit; infuse slowly and only if ventilation is adequate
• Contraindications and precautions
- There are contraindications during an arrest.
- Calcium may be used if known (preexisting) hyperkalemia precipitated arrhythmia; calcium is contraindicated in hyperkalemia secondary to digoxin.
- Magnesium is relatively contraindicated in renal failure, but given the consequences of not terminating rhythm; this is only a relative contraindication in this setting.
Second Line
Asystole: Aminophylline 250 mg IV bolus has been effective in uncontrolled trials, but should be used only when conventional therapy has failed.
SURGERY
If indicated
• Pericardiocentesis to treat cardiac tamponade
• Needle decompression (second intercostal space midclavicular line), then chest tube insertion to treat tension pneumothorax
FOLLOW-UP
PROGNOSIS
• Outcome is related to underlying disease, age, duration of arrest, and other factors.
• Outcome is poor if
- >4 minutes to CPR or >8 minutes to ACLS
- Arrest occurs in field
- Resuscitation effort >30 minutes
• About 14% survive in-hospital arrest, fewer after field arrest
COMPLICATIONS
• Significant neurologic, hepatic, renal, or cardiac ischemic injury
• Rib fractures or pneumothorax from CPR
PATIENT MONITORING
Intensive care setting on continuous monitor to look for precipitating cause, including serial ECGs and enzymes to rule out myocardial infarction
REFERENCES
1. Wik L, Hansen TB, Fylling F, et al. Delaying defibrillation to give basic cardiopulmonary resuscitation to patients with out-of-hospital ventricular fibrillation: A randomized trial. JAMA. 2003;289(11):1389-1395.
2. Graber MA. Emergency medicine. In: Graber MA, Lanternier ML, Graber M, eds. The Family Practice Handbook. St. Louis, MO: Mosby-Yearbook; 1997.
3. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation. Guidelines 2000 for cardiopulmonary resuscitation and emergency cardiovascular care. Circulation. 2000;102(suppl 8):I95-I104.
MISCELLANEOUS
Make sure patient is not listed as Do Not Resuscitate.