PALS Part 2.2 (11-13)(Cardiac Arrest, Arrhythmias, & ROSC) Flashcards
What is the main cause of bradycardia in kids and what is it typically an impending sign of deterioration to?
Symptomatic bradycardia is most often the RESULT of tissue hypoxia and is often an impending sign of cardiac arrest
Primary Vs Secondary Bradycardia
Primary Bradycardia:
- Is the result of congenital or acquired heart conditions that slow the spontaneous depolarization rate of the heart’s normal pacemaker cells or slow conduction through the heart’s conduction system.
- Primary causes include:
a) congenital problems of the heart and pace maker or conduction system
b) surgical injury to the pacemaker or conduction system
c) cardiomyopathy
d) myocarditis
Secondary Bradycardia:
- Is the result of noncardiac conditions that alter the normal function of the heart (i.e. slow the sinus node pacemaker or slow conduction through the atrioventricular junction)
- Primary causes include:
a) hypoxia
b) acidosis
c) hypotension
d) hypothermia
e) drug effects
f) increased vagal tone (suctioning, gagging, vomiting)
What are the 5 types of bradycardia?
- Sinus Brady
- AV Block: 1st degree
(prolonged PRI) - AV Block: 2nd Degree Type 1 (Wenckebach)
(longer and longer PRI until dropped QRS) - AV Block: 2nd Degree Type 2
(constant PRI but dropped QRSs) - AV Block: 3rd Degree (Complete Heart Block)
What is the most common cause of SVT in children and infants?
Reentry pathways in the AV node
BONUS: SVT is the most common tachyarrhythmia in children
(remember that tachycardia is normal but tachyarrhythmia is when the rate is abnormally fast and stems from an abnormal cause)
Does a tachyarrhythmia always produce symptoms within a relatively quick time frame?
NO, tachyarrhythmias can take hours to days to progress to hemodynamic instability.
Often the first symptoms felt include heart palpitations, syncope, or light headedness.
LOOK OVER COMPARISON CHART OF ST AND SVT ON PAGE 239
LOOK OVER COMPARISON CHART OF ST AND SVT ON PAGE 239
REVIEW ECG RHYTHM CHARACTERISTICS; COMPARE THE BOOK AND THE ECG QUICK STUDY GUIDE SAVED ON DESKTOP
REVIEW ECG RHYTHM CHARACTERISTICS; COMPARE THE BOOK AND THE ECG QUICK STUDY GUIDE SAVED ON DESKTOP
5 conditions that predispose to Torsades de pointes?
- Long QT syndrome
- Hypomagnesemia
- Hypokalemia
- Antiarrhythmic drug toxicity
- Other drug toxicities
What are the 3 major signs when assessing a pt that tells you they are unstable?
- AMS
- Hypotension
- Signs of Shock
When symptomatic bradycardia is persistent despite O2, ventilations, and CPR, what is the next steps?
What drugs are included or should be considered?
- Continue CPR
- IV/IO Access
- EPINEPHRINE:
Has A1, B1, B2 adrenergic activity. (a1 = vasoconstriction, B1 = increased heart rate, contractility, conductivity, B2 = bronchodilation). Epi = catecholamine, & catecholamine effects can be reduced by acidosis and hypoxia which makes airway, vent, O2, and compression support so vital to make the drug effective. - ATROPINE:
Is a Parasympatholytic or anticholinergic drug that accelerates sinus or atrial pacemakers and enhances AV conduction. Atropine should be used instead of Epi when the brady is caused by increased vagal tone, cholinergic drug toxicity (organophosphates), or complete AV block. It should NOT be used over epi for AV blocks caused by bradycardia stemming from a root problem of hypoxia or acidosis (treatable causes). The reasoning for this will be on another note card - Consider Transthoracic/Transvenous Pacing:
This is typically only indicated when an AV block occurs after surgical correction of a congenital heart disease. But may be useful in brady caused by complete heart block or abnormal sinus node function
** POSSIBLE TEST QUESTIONS, IT WAS A QUIZ Q - Identify and Treat underlying causes; i.e. Hs & Ts
When should atropine be used instead of Epi in a persistent symptomatic bradycardic patient? When should it NOT be used instead of Epi? WHY?
Atropine is a Parasympatholytic or anticholinergic drug that accelerates sinus or atrial pacemakers and enhances AV conduction.
Atropine should be used instead of Epi when the brady is caused by increased vagal tone, cholinergic drug toxicity (organophosphates), or complete AV block.
It should NOT be used over epi for AV blocks caused by bradycardia stemming from a root problem of hypoxia or acidosis (treatable causes).
The reasoning for wanting to sometimes use atropine over epi is that epi can cause ventricular arrhythmias if the myocardium is chronically abnormal or hypoxic/ischemic. HOWEVER, if the child does not respond to first line atropine then use epi
If the child is stable and has a narrow tachyarrhythmia how many attempts at vagal maneuvers should you do before moving on to more advanced conversion techniques?
Why is a vagal maneuver helpful and what are 2 ways you can do it for children?
2 attempts before moving on
Some tachyarrhythmias stem from a loss of vagal nerve tone and doing a vagal maneuver increases that loss of tone which should hopefully decrease the heart rate
For infants and children of all ages you can apply a plastic bag mixed with water and ice and apply it to the upper half of the child’s face for 15-20 seconds; DO NOT occlude the nose or mouth
OR
Do the classic Valsalva maneuver by having them blow through a narrow straw (not for infants or small children)
Which drugs are used in tachyarrhythmias?
Adenosine and Amiodarone
REVIEW PG 251-252 WHICH HAS INDICATIONS/PRECAUTIONS, DOSAGE/ADMINISTRATION AND MOA
When do you have time to consider an analgesic and sedation before synchronized cardioversion?
When the child is hemodynamically stable aka non-symptomatic. When the child is unstable, DO NOT delay synch cardioversion
Remember that when synchronized, the manual defibrillator will wait to deliver the shock after you press the button until it is aligned with an R wave.
Important considerations, indications, and dosages of Synchronized Cardioversion
IMPORTANT CONSIDERATIONS:
- most units will auto default to UNsynchronized cardioversion so you have to make sure to specifically push the sync button each time
- If the R waves are undifferentiated or too low amplitude, in which case you must increase the gain of the ECG or switch to a diff lead
- Synchronization may take extra time
INDICATIONS:
- Hemodynamically unstable patients with tachyarrhythmias, but with palpable pulses
- Elective cardioversion, under the direction of a pediatric cardiologist, for children with hemodynamically stable SVT, atrial flutter, or VT with a pulse
ENERGY DOSE:
- start with 0.5-1J/kg for cardioversion of SVT or VT w/ pulse
- If ineffective increase to 2J/kg