Cardiology In Critical Care



After review/study of these pages and attendance at a Critical Care Nursing Skills Lab, the critical care nurse will be able to:

  1. State the two dysrhythmias for which defibrillation is indicated.
  2. Given a hypothetical patient scenario, demonstrate the proper emergency measures to be followed.
  3. State two key differences between adult and pediatric defibrillation.


OVERVIEW: Defibrillation is achieved by delivering a strong electric current though electrodes placed on the surface of a patient’s chest wall. Proper electrode placement ensures that the axis of the heart is directly situated between the sources of current (defibrillator paddles). Since dysrhythmias are chaotic with no coordinated ventricular response, the electric current is delivered randomly. It is through implementation of emergent defibrillation that ventricular fibrillation and pulseless ventricular tachycardia can be terminated and cardiac output restored.


  1. To eradicate life-threatening ventricular fibrillation or pulseless ventricular tachycardia.
  2. To restore cardiac output lost due to dysrhythmias and reestablish tissue perfusion and oxygenation.


  1. Defibrillator
  2. Conductive medium- defibrillator pads
  3. Cardiac monitor with recorder
  4. Emergency cart and medications
  5. Emergency pacing equipment



  1. Verify V-fib or V-tach by ECG and correlate with clinical state. Assess to determine absence of pulse. Call for help and perform CPR until defibrillator and crash cart arrives.
  2. Prepare for defibrillation
  1. Turn power "ON". Defaults to 200 joules.
  2. Select correct paddles- adult, pediatric or internal.
  3. Prepare patient and/or paddles with proper conductive agent.
  4. Checks that defibrillator is in asynchronous mode.
    If other than 200 joules desired, press "ENERGY SELECT" and select desired amount
  1. Turn on ECG recorder for continuous printout.
  2. Places one paddle at the heart’s Apex just left of the nipple in midaxillary line. Place the other paddle just below the right clavicle to the right of the sternum, applying 25 lbs. / square inch pressure to paddles.
  3. ***Press "CHARGE" on defibrillator front panel or on the Apex paddle. Wait until indicator stops flashing to indicate fully charged.
  4. ***State "ALL CLEAR" and visually check that all personnel are clear of contact with bed, patient and equipment.
  5. ***Checks rhythm immediately before discharge.
  6. 8. Depress both buttons simultaneously and maintain pressure until electrical current delivered. (Maintain 25 lbs/in2)
  7. ***Assess conversion of dysrhythmia.
  8. 10. If first defibrillation unsuccessful, immediately charge paddles to 300 joules and repeat steps 2 through 9.
  9. If second defibrillation unsuccessful, immediately charge paddles to 360 joules and repeat steps 2 through 9.
  10. If third attempt is unsuccessful, continue CPR, initiate ACLS protocols, intubate and obtain IV access. Assess patient status and precipitating factors to prevent further decompensation of patient.
  11. Clean defibrillator and paddles, discard supplies, and wash hands.
  12. Documents procedure in patient record or cardiac arrest flowsheet.

RATIONALE/Nursing Considerations

  1. May be mistaken for artifact or leads may be off.
  2. Asses situation. If a second person is getting the defibrillator, establish an airway and begin CPR.
  1. Convert to pediatric size for children or internal if the patient is has an open chest.
  2. Enhances electrical conduction through subcutaneous tissue and assists in minimizing burns.
  3. Limit to paddle area.Use 2 joules/kg for children.
  4. Will not fire if it is in synchronous mode due to absence of R wave
  1. Establishes a visual recording and a permanent record of current ECG status and response to intervention.
  2. Defibrillation s achieved by passing an electric current through cardiac muscle mass to restore a single source of impulse generation. Decreases transthoracic resistance and improves flow of current across axis of heart.
  3. This will charge unit with current.
  4. Maintains safety to caregivers, since electric current can be conducted from the patient to another individual if contact occurs.
  5. ECG rhythm may change, ensure it is a rhythm that requires defibrillation.
  6. Premature release may result in failure to discharge energy. May also be delivered by depressing discharge button on the defibrillator.
  7. If rhythm has converted, must reassess.
  8. Immediate action increases chance for successful depolarization of cardiac muscle. Transthoracic resistance decreases by approximately 8 % with the second shock.
  9. Immediate action increase chance of successful depolarization of cardiac muscle. "Stacked shocks" sequence is more important than adjunctive drug therapy and delays between shocks to deliver medications are detrimental.
  10. Necessary to maintain the delivery of oxygenated blood to vital organs.
  11. Conductive gel accumulated on defib paddles impedes surface contact and increases transthoracic resistance.
  12. Provides for completion of medical/ nursing records.



  1. Neurologic status. Reorient to person, place, and time.
  2. Respiratory status. Auscultate lung sounds, Monitor rate, depth, & quality of breathing. Oxygen as ordered.
  3. Cardiovascular status. Get 12-lead ECG and continue to monitor rhythm and blood pressure, pulse and respirations frequently until stable.
  4. Initiate IV antidysrhythmic therapy.
  5. Monitor for burns. Treat if indicated.
  6. Documentation. Include neurologic, respiratory and cardiovascular assessment before and after defibrillation. All code related information should be completed on the code summary flowsheet.
  7. Patient/family education. Assess understanding of past, current and future needs.


  1. Temporary altered LOC occurs following defibrillation. Cerebral anoxia or emboli may develop as a post-procedure complication.
  2. Respiratory centers of the brain may be depressed as a result of hypoxia.
  3. Dysrhythmias may develop after defibrillation .
  4. Ventricular dysrhythmias are indicative of myocardial irritability, and if antidysrhythmic therapy is not administered, recurrence of ventricular dysrhythmias is probable.
  5. Electric current in contact with subcutaneous tissue can cause loss of skin integrity.
  6. Provides a record of pre-procedure patient status, nursing interventions, post-procedure patient status, and both expected and unexpected outcomes. Serves as a legal medical record of the events.
  7. Prepares patient and family for both expected and unexpected outcomes.


  1. Check all equipment for proper grounding to prevent current leakage.
  2. Disconnect temporary pacemaker and other electrical equipment.
  3. Do not defibrillate directly over an implanted pacemaker. Defibrillation may result in damage to equipment.


  1. Support patient and family as necessary after defibrillation.
  2. Clear defibrillator of remaining electrical current immediately; never set charged defibrillator paddles down. Prepare equipment for future use.
  3. Support patient with CPR as appropriate.
  4. Check possible causes of failure to convert ventricular dysrhythmias:
  1. Defibrillator not functioning
  2. Debris on paddles which impairs conductivity
  3. Low amplitude fibrillatory waves, which can be associated with long-standing ventricular fibrillation, acidosis and hypoxia; this requires CPR measures prior to defibrillation.
  4. Frayed wires and faulty equipment.
  1. Recognize the following differences for internal defibrillation:
  1.  Use sterile internal defibrillator paddles.
  2.  Use sterile gel pads between myocardium and defibrillation paddles.
  3.  Charge defibrillator to prescribed voltage; a significantly lower (15-30 joules) energy level is used.
  1. Recognize the following changes for pacemaker defibrillation:
  1. Turn off temporary external pacemaker.
  2. Avoid placing defibrillator paddles over permanent pulse generator or electrode.


  1. Dysrhythmias Pulmonary edema
  2. Cardiac arrest Pulmonary or systemic emboli
  3. Respiratory arrest Equipment malfunction
  4. Neurologic impairment Death
  5. Altered skin integrity

Reference: Advanced Cardiac Life Support, 1994 American Heart Association.

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This page last updated 07/25/10