Friday, September 30, 2011

ACLS review: SVT part 6


Synchronized cardioversion
·         Specific timed delivery of electrical shock to the heart
·         Treatment of choice for SVT, VT with a pulse and atrial flutter with evidence of poor profusion
·         Provide sedation and analgesia
·         Prepare to defibrillate immediately if cardioversion causes VF
Note
Synchronized cardioversion is shock delivery that is timed (synchronized) with the QRS complex. This synchronization avoids shock delivery during the relative refractory period of the cardiac cycle when a shock could produce VF.
 
Indications
·         All tachycardias (rate >150 bpm) with serious signs and symptoms related to the tachycardia.  These include unstable SVT, atrial flutter, atrial fibrillation and unstable VT
·         May give brief trial of medications based on specific arrhythmias.
Note
Cardioversion is less likely to be effective for treatment of junctional tachycardia or ectopic or multifocal atrial tachycardia because these rhythms have an automatic focus, arising from cells that are spontaneously depolarizing at a rapid rate




Precautions
·         In critical conditions go to immediate unsynchronized shocks.
·         Urgent cardioversion is generally not needed if heart rate is over 150 bpm.
·         Reactivation of sync mode is required after each attempted cardioversion (defibrillators/cardioverters default to unsynchronized mode).
·         Prepare to defibrillate immediately if cardioversion causes VF.
·         Synchronized cardioversion cannot be performed unless the patient is connected to monitor leads; lead select switch must be on lead I, II, or III and not on “paddles.”


Reviewed 2/28/16

Thursday, September 29, 2011

ACLS review: SVT part 5

Note
For verapamil, give a 2.5 mg to 5 mg IV bolus over 2 minutes (over 3 minutes in older patients). If there is no therapeutic response and no drug-induced adverse event, repeated doses of 5 mg to 10 mg may be administered every 15 to 30 minutes to a total dose of 20 mg. An alternative dosing regimen is to give a 5 mg bolus every 15 minutes to a total dose of 30 mg


Beta blockers (class 1)
Esmolol: 0.5mg/kg bolus over 1 minutes followed by an infusion at 50mcg/kg/min for 4 minutes. If no response then repeat 0.5mg/kg bolus over 1 minute and increase maintenance infusion to 100mcg/kg/min. If inadequate response in 4 minutes, repeat 0.5mg/kg bolus over 1 minute and increase maintenance infusion to 150mcg/kg/min. If inadequate response in 4 minutes, continue repeating bolus dose and increasing maintenance infusion by 50mcg/kg/min until maximum infusion of 300mcg/kg/min has been reached.

Metoprolol: 5mg slow IV push over 5 minutes x 3 as needed to a total dose of 15mg over 15 minutes

Note
In principle these agents exert their effect by antagonizing sympathetic tone in nodal tissue, resulting in slowing of conduction. Like calcium channel blockers, they also have negative inotropic effects and further reduce cardiac output in patients with heart failure

Digoxin (IIb)
·         10-15mcg/kg
·         Usually 0.25mg IV q4h x 4 loading dose, then oral maintenance dose
·         Not useful in emergencies due to slow onset of action



Reviewed 2/28/16


Wednesday, September 28, 2011

ACLS review: SVT part 4

Adenosine
·         6mg rapid IV over 2-3sec.
·         Repeat Adenosine at 12mg rapid IV over 2-3sec.
·         Reduce dosage in patients using Tegretol or dipyridamole
·         Relatively contraindicated in patient with asthma


Note
If the rhythm does not convert within 1 to 2 minutes, give a 12 mg rapid IV push using the method above. The initial dose may be reduced to 3 mg in patients taking dipyridamole or carbamazepine, those with transplanted hearts, or if given by central venous access. Side effects with adenosine are common but transient; flushing, dyspnea, and chest discomfort are the most frequently observed.  Adenosine should not be given to patients with asthma.


Adenosine
·         Adenosine should be considered for stable monomorphic, regular wide complex tachycardia
·         Adenosine should not be used for irregular wide complex tachycardia


Pause after Adenosine









Calcium channel blockers (class 1)
·         Diltiazem: 0.25mg/kg over 2 minutes.  If ineffective, in 15 minutes may repeat 0.35mg/kg over 2 minutes.  Followed by a maintenance infusion of 5-15mg/hr
·         Verapamil: 2.5-5.0mg slow IV push over 2 minutes. May repeat with 5-10mg in 15 to 30 minutes. Maximum dose 20mg
Note
These drugs act primarily on nodal tissue either to terminate the reentry PSVTs that depend on conduction through the AV node or to slow the ventricular response to other SVTs by blocking conduction through the AV node. The alternate mechanism of action and longer duration of these drugs may result in more sustained termination of PSVT or afford more sustained rate control of atrial arrhythmias

Reviewed 2/28/16




Tuesday, September 27, 2011

ACLS review: SVT part 3

Precautions for Carotid Sinus Massage
·         Avoid carotid massage in older adults
·         Never perform bilateral carotid massage
·         Listen for bruits before carotid massage- contraindicated if bruits are present
·         Should not be continued for more than 10 sec.
·         Patient should be on cardiac monitor
·         Should have IV access before attempting vagal maneuvers


Procedure for carotid sinus massage
·         Turn head to the left
·         Apply firm pressure over the right carotid bifurcation near the angle of the jaw
·         If unsuccessful, repeat with a 5- to 1- second rotary “massage motion”
·         If unsuccessful, turn the head to the right side and perform left carotid massage


Contraindications
·         Avoid in elderly
·         Carotid bruits
·         History of CVA
·         Recent MI or myocardial ischemia

Medications Used to Treat Stable (symptomatic) SVT
·         Adenosine
·         Calcium channel blockers (class 1)
·         Beta blockers (class 1)
·         Digoxin


Reviewed 2/28/16







Monday, September 26, 2011

ACLS review: SVT part 2


Evaluate Rhythm
·         Obtain 12 lead EKG
·         Determine if QRS complex is ≥0.12 second
·         Determine treatment options.


Note:  Stable patients may await expert consultation because treatment has the potential for harm


Narrow Complex Tachycardias
·         Atrial fibrillation
·         Atrial flutter
·         AV nodal reentry
·         Accessory pathway–mediated tachycardia
·         Atrial tachycardia (including automatic and reentry forms)
·         Multifocal atrial tachycardia (MAT)
·         Junctional tachycardia (rare in adults)


Note:  Irregular narrow-complex tachycardias are likely atrial fibrillation or MAT; occasionally atrial flutter is irregular


Wide Complex Tachycardias
·         Ventricular tachycardia (VT
·         SVT with aberrancy
·         Pre-excited tachycardias (Wolff-Parkinson-White [WPW] syndrome)
 

Note:  Because ACLS providers may be unable to distinguish between supraventricular and ventricular rhythms, they should be aware that most wide-complex (broad-complex) tachycardias are ventricular in origin.


Vagal maneuvers
·         Carotid sinus massage
·         Coughing
·         Valsalva maneuver
·         Stimulation of gag reflex
·         Digital rectal stimulation


Rationale
·         Depresses AV node and sinus node
·         Terminates AV nodal reenterant tachycardia
·         Clarifies rhythm


Valsalva Maneuver
·         Performed by the patient (patient must be conscious and cooperative)
·         Document the dysrhythmia before treating
·         Explain the procedure to the patient
·         Instruct the patient to inhale and hold their breath and:
·         Bear down as if to have a bowel movement, and to hold this position for 20-30 seconds.


Reviewed 2/28/16

Sunday, September 25, 2011

ACLS review: SVT part 1

Management of SVT




Mnemonic for Treating SVT
Primary Survey
Recognize symptoms of instability
Evaluate rhythm- EKG
Vagal Maneuvers
Adenosine
Direct cardioversion
Expert consultation

Primary Survey
·         Airway- supplemental oxygen
·         Breathing
·         Circulation
·         Check VS
·         Assess pulse
·         Attach defibrillator/monitor
·         12 lead EKG
·         IV access


Recognize Symptom of Instability?
·         Evaluate the patient: symptomatic or unstable
·         Identify potential reversible causes of the tachycardia

Note:
Many experts suggest that when a heart rate is <150 beats per minute, it is unlikely that symptoms of instability are caused primarily by the tachycardia unless there is impaired ventricular function.


Symptomatic Tachycardia
·         Symptomatic implies that an arrhythmia is causing symptoms, such as palpitations, lightheadedness, or dyspnea, but the patient is stable and not in imminent danger.
·         In such cases more time is available to decide on the most appropriate intervention


Unstable Tachycardia
·         Refers to a condition in which vital organ function is acutely impaired or cardiac arrest is ongoing or imminent.
·         When an arrhythmia causes a patient to be unstable, immediate intervention is indicated


Symptoms of Instability
·         Chest pain
·         Syncope
·         Shortness of breath
·         Cold and clammy skin
·         Decreased level of consciousness
·         Hypotension
·         Pulmonary congestion

Reviewed 2/28/16

Saturday, September 24, 2011

ACLS review: Bradycardia part 9

Tension Pneumothorax
·         Hx trauma, recent pacemaker or central line insertion, ventilator patient
·         Assess for tracheal deviation
·         Needle decompression 2nd intercostal space midclavicular line
·         Chest tube

Thrombosis, Coronary
·         MONA
·         Follow ACS algorithm


References
Aehlert, Barbara. ACLS Quick Review Study Guide, 2nd edition.  Mosby, inc.  St. Louis, Mo. 1994.
Neumar RW, Otto CW, Link MS, Kronick SL, Shuster M, Callaway CW, Kudenchuk PJ, Ornato JP, McNally B, Silvers SM, Passman RS, White RD, Hess EP, Tang W, Davis D, Sinz E, Morrison LJ. Part 8: adult advanced cardiovascular life support: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(suppl 3):S729–S767


Reviewed 2/28/16

Friday, September 23, 2011

ACLS review: Bradycardia part 8

Hypokalemia
·         Slow rhythm with ST segment depression, flattened waves, prominent U wave
·         Potassium replacement either orally or IV
·         No IV push boluses!

Tablets
·         Assess for drug overdose
·         Assess for hx of drug use
·         Consult poison control

Tablets: Calcium Channel Blockers
·         Hypotension
·         Bradycardia with variable heart block
·         Altered mental status
·         EKG: slow rate, prolonged PRI, AV blocks
·         Rx Calcium chloride 10% 1-4G slow IV
·         Fluid resuscitation, vasopressor agents, atropine, transvenous pacing

Tablets: Beta blockers
·         Hypotension
·         Bradycardia with variable heart block
·         EKG: slow rate, prolonged PRI
·         Rx Glucagon 3-10mg IV bolus followed by infusion 2-5mg/hr

Tablets: Tricyclic Antidepressants
·         Amitriptyline, Doxepine, Trazadone, Nortriptyline
·         Prolonged QT, Widened QRS
·         3Cs & 1A - Cardiac dysrhythmias, Convulsions, Coma, & Acidosis
·         Rx NaHCO3 bolus or infusions
·         Maintain pH > 7.45


Reviewed 2/28/16