PALS Part 2.2 (11-13)(Cardiac Arrest, Arrhythmias, & ROSC)

Question 1

What is the main cause of bradycardia in kids and what is it typically an impending sign of deterioration to?

Answer 1

Symptomatic bradycardia is most often the RESULT of tissue hypoxia and is often an impending sign of cardiac arrest

Question 2

Primary Vs Secondary Bradycardia

Answer 2

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)

Question 3

What are the 5 types of bradycardia?

Answer 3

• 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)

Question 4

What is the most common cause of SVT in children and infants?

Answer 4

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)

Question 5

Does a tachyarrhythmia always produce symptoms within a relatively quick time frame?

Answer 5

NO, tachyarrhythmias can take hours to days to progress to hemodynamic instability.

Often the first symptoms felt include heart palpitations, syncope, or light headedness.

Question 6

LOOK OVER COMPARISON CHART OF ST AND SVT ON PAGE 239

Answer 6

LOOK OVER COMPARISON CHART OF ST AND SVT ON PAGE 239

Question 7

REVIEW ECG RHYTHM CHARACTERISTICS; COMPARE THE BOOK AND THE ECG QUICK STUDY GUIDE SAVED ON DESKTOP

Answer 7

REVIEW ECG RHYTHM CHARACTERISTICS; COMPARE THE BOOK AND THE ECG QUICK STUDY GUIDE SAVED ON DESKTOP

Question 8

5 conditions that predispose to Torsades de pointes?

Answer 8

• Long QT syndrome
• Hypomagnesemia
• Hypokalemia
• Antiarrhythmic drug toxicity
• Other drug toxicities

Question 9

What are the 3 major signs when assessing a pt that tells you they are unstable?

Answer 9

• AMS
• Hypotension
• Signs of Shock

Question 10

When symptomatic bradycardia is persistent despite O2, ventilations, and CPR, what is the next steps?
What drugs are included or should be considered?

Answer 10

• 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

Question 11

When should atropine be used instead of Epi in a persistent symptomatic bradycardic patient? When should it NOT be used instead of Epi? WHY?

Answer 11

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

Question 12

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?

Answer 12

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)

Question 13

Which drugs are used in tachyarrhythmias?

Answer 13

Adenosine and Amiodarone

REVIEW PG 251-252 WHICH HAS INDICATIONS/PRECAUTIONS, DOSAGE/ADMINISTRATION AND MOA

Question 14

When do you have time to consider an analgesic and sedation before synchronized cardioversion?

Answer 14

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.

Question 15

Important considerations, indications, and dosages of Synchronized Cardioversion

Answer 15

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

Question 16

REVIEW SYNCHRONIZED CARDIOVERSION PROCESS STEPS ON PG 255

Answer 16

REVIEW SYNCHRONIZED CARDIOVERSION PROCESS STEPS ON PG 255

Question 17

What is another medication that can be given instead of Amiodarone for an unstable tachyarrhythmic pt?

Answer 17

Procainamide at 15mg/kg over 30-60 minutes

This and amio SHOULD NOT be given routinely without expert consultation and SHOULD NOT be given together or with other drugs that also prolong the QT interval

Question 18

Which assessment technique should you use to assess the pt after a cardiac arrest and ROSC is achieved?

Answer 18

Systematic Approach to the Seriously Ill or Injured Child

Question 19

What are the primary goals of post-cardiac arrest care?

Answer 19

• Optimize and stabilize airway, oxygenation, ventilation, and cardiopulmonary function with emphasis on restoring and maintaining vital organ perfusion and function (especially the brain)
• Prevent secondary organ injury
• Identify and treat the causes of acute illness
• Institute measures that may improve long-term, neurologically intact survival
• Minimize the risk of deterioration of the child during transport to a higher level of care

Question 20

How do you treat organ system dysfunction in a cardiac arrest or post cardiac arrest situation?

Answer 20

• provide O2 and ventilations
• support tissue perfusion and cardiovascular function
• avoiding hypotension
• correcting acid-base and electrolyte imbalances
• maintaining appropriate glucose concentration
• providing targeted temp management
• ensuring adequate analgesia and sedation

Question 21

What are the 2 general phases of stabilizing a child in Post-cardiac arrest care?

Answer 21

FIRST PHASE is immediate post cardiac arrest care that focuses on continuing advanced life support for immediate life-threatening conditions and focus on the ABC’s

SECOND PHASE is when you should provide a broader multiorgan supportive care including targeted temp management

Question 22

What are the 3 main body systems that we are trying to assess and manage during post-cardiac arrest care (once beyond stabilization of the ABC’s)

Answer 22

• Respiratory System
• Cardiovascular System
• Neurologic System

Question 23

Review of 4 different parameters of the cardiovascular system that may need improving and how to do it (generally speaking)

Answer 23

PRELOAD:
- Admin Fluid Bolus

CONTRACTILITY:

• Admin inotropes or inodilators
• Correct hypoxia, electrolyte, and acid-base imbalances, and hypoglycemia/hypocalcemia
• Treat poisonings

AFTERLOAD (SVR):
- Admin vasopressors or vasodilators as needed

HEART RATE:

• Admin chronotropes for brady (epi)
• Admin antiarrhythmics
• Correct hypoxia
• Consider pacing

Question 24

Post Cardiac arrest shock dosages of Epi, Norepi, and Milrinone depending on whether the shock remains hypotensive after fluid resuscitation attempts or returns to normotensive but still shows signs of hypoperfusion?

Answer 24

REFRACTORY HYPOTENSIVE SHOCK POST CA CARE:
- Epi = IV/IO 0.03-0.2mcg/kg per minute*
AND/OR
- Norepi = IV/IO 0.03 to 0.5mcg/kg per minute*

NORMOTENSIVE SHOCK POST CA CARE: (still hypoperfused)
- Low Dose Epi = IV/IO 0.03-0.05mcg/kg per minute*
AND/OR
- Milrinone: IV/IO load with 50mcg/kg over 10-60 minutes. Loading doses by cause hypotension; infuse 0.25-0.75 mcg/kg per minute

Epinephrine can either increase or decrease SVR depending on INFUSION DOSE. Low-dose infusions generally produce more B-Adrenergic affects (increased HR, contractility, and vasodilation). Higher doses produce more A-Adrenergic affects (vasoconstriction)

Norepi is a potent inotropic and peripheral vasoconstricting agent, titrate to effect for low SVR correction that is unresponsive to fluid boluses

MILRINONE is an indicator that augments cardiac output with little effect on heart rate and myocardial O2 demand. Inodilators are used for treatment of myocardial dysfunction with increased SVR or pulmonary vascular resistance. BE AWARE that additional fluids will probably be needed in conjuncture with a Milrinone dose b/c of the vasodilatory effects expanding the vascular space which could CAUSE HYPOTENSION. Inodilators have a LONG HALFLIFE and in consequence the side effects can last a long time after stopping admin and it may take along time for the pt to show signs of adjusting to a change in drip dosage (4.5 hours)

Question 25

What are inodilators like Milrinone used for?

Answer 25

Inodilators are used for treatment of myocardial dysfunction with increased SVR or pulmonary vascular resistance.

BE AWARE that additional fluids will probably be needed in conjuncture with a Milrinone dose b/c of the vasodilatory effects expanding the vascular space which could CAUSE HYPOTENSION. Inodilators have a LONG HALFLIFE and in consequence the side effects can last a long time after stopping admin and it may take along time for the pt to show signs of adjusting to a change in drip dosage (4.5 hours)

Question 26

What is the 4-2-1 method of Maintenance Fluid Calculation?

Answer 26

It is based on weight corresponding to estimated hourly fluid requirements.

WEIGHT: <10kg
EST HOURLY FLUID REQ: 4mL/kg/hr
EX: 8kg infant: 4mL/kg/H x 8kg = 32mL/H

WEIGHT: 10-20kg
EST HOURLY FLUID REQ: 40ml/H + 2mL/kg/H for each kilogram between 10-20kg
EX: 15kg child: 40mL/H + (2mL/kg/H x 5kg) = 50mL/H

WEIGHT: >20kg
EST HOURLY FLUID REQ: 60ml/H + 1mL/kg/H for each kilogram above 20kg
EX: 30kg child: 60mL/H + (1mL/kg/H x 10kg) = 70mL/H

Question 27

Why should a fever be treated against so aggressively in a post cardiac arrest patient?

Answer 27

A fever (38degree C or higher) will negatively affect the recovery from ischemic brain injury. Metabolic O2 demand increases by 10-13% for each degree C above normal temp. Fevers also increase the release of inflammatory mediators, cytotoxic enzymes, and neurotransmitters, which increase brain injury.

To fight fevers use antipyretics such as acetaminophen or ibuprofen, and targeted temp management aimed at a core temp of 32-37degree C UNLESS hypothermia is a root cause of the cardiac arrest.