Pediatric Shock

Question 1

What are the three broad determinants of blood pressure?

Answer 1

1) Blood volume
2) Cardiac output
3) Systemic vascular resistance

Question 2

What is meant by cardiac output?

Answer 2

Refers to the volume of blood pumped per unit of time, usually 1 minute

In other words, cardiac output is the amount of blood the heart pumps in one minute.

Question 3

How is cardiac output calculated?

Answer 3

Stroke volume x heart rate (bpm)

Question 4

What is meant by stroke volume?

Answer 4

Stroke volume refers to the volume of blood pumped in each beat

Question 5

What are the determinants of stroke volume?

Answer 5

1) Preload
2) Contractility
3) Afterload

Question 6

What is the lowest normal systolic bp in neonates?

Answer 6

60

Question 7

What is the lowest normal systolic bp in infants?

Answer 7

70

Question 8

What is the lowest normal systolic bp in children 2-10y?

Answer 8

70 + (age x2)

Question 9

What is the lowest normal systolic bp in children > 10y?

Answer 9

90

Question 10

What is shock?

Answer 10

Shock can be defined as a pathophysiologic state characterized by inadequate tissue perfusion to meet tissue demand

Insomuch as it is the role of the circulatory system to provide adequate tissue perfusion, shock can be conceptualized as circulatory failure

Can also be thought of generalized perfusion/demand mismatch

Question 11

How is shocked diagnosed?

Answer 11

Shock is a CLINICAL diagnosis base on overall clinical picture

NOT based on blood pressure, esp. in children wherein hypotension is a late finding

Normotensive patients may be in shock!!!

NOT based on laboratory markers of end-organ perfusion

Question 12

Aside from hypotension and tachycardia, name 5 potential clinical signs of shock.

Answer 12

1) AMS
2) Skin changes - pale, cool, mottled skin
3) Pulses - weak or “thready”
4) Decreased capillary refill tiime
5) Decrease urine output

Question 13

What is meant by compensated shock?

Answer 13

Compensated shock refers to a state in which there are clinical signs of inadequate tissue perfusion but the systolic blood pressure remains in a normal range. Compensated shock is contrasted with hypotensive shock.

Question 14

What are the four broad categories of shock based on pathophysiology?

Answer 14

Hypovolemic

Obstructive

Cardiogenic

Distributive

Question 15

Provide a mnemonic approach to differential diagnosis for a child in shock.

Answer 15

InASHOCK

In - internal hemorrhage (occult trauma, GI bleeding, ruptured ectopic, AAA)

A - anaphylactic shock

S - septic shock

H - hypovolemic shock (GI losses, GU losses / DKA)

O - obstructive shock (massive PE, tension pneumothorax, cardiac tamponade)

C - cardiogenic shock (myocardial, arrhythmia, drug-induced)

K - endocrine shock

Question 16

You diagnose a child with shock. Provide an approach to determining the underlying cause.

Answer 16

1) History - SAMPLE history
2) Physical exam
3) RUSH protocol u/s assessment
4) Appropriate laboratory work-up

Question 17

Describe the RUSH protocol.

Answer 17

HI-MAP mnemonic

H - heart

I - IVC

M - Morrison’s pouch

A - aorta

P - pulmonary assessment

Question 18

How do infants and young children differ from older children, adolescents, and adults in terms of their ability to adjust stroke volume?

Answer 18

Infants have a very small stroke volume with a very limited ability to increase.

They are therefore dependent on an adequate heart rate to maintain cardiac output.

In other words, to increase cardiac output, the infant must increase their heart rate as stroke volume is relatively fixed

The clinical significance of this is that tachycardia in infant is serious

Question 19

What is meant by cold and warm shock?

Answer 19

Cold shock:

Characterized by peripheral vasoconstriction and cool clammy skin
Results from cardiogenic, obstructive, and hypovolemic shock
Pump or tank problem

Warm shock:

Characterized by peripheral vasodilation.
Results from early distributive shock
Results in warmer skin and bounding pulses. This state is sometimes called “warm shock.”
Pipes problem

As distributive shock progresses, however, concomitant hypovolemia and/or myocardial dysfunction produce a decrease in cardiac output. SVR can then increase, resulting in “cold shock.”

In other words, the “warm shock” or early distributive shock eventually becomes “cold” like the others.

Question 20

What are the two broad treatment strategies in shock?

Answer 20

1) Improve perfusion (increase supply)

2) Reduce demand

Question 21

How can oxygen demand be reduced?

Answer 21

Treat increased work of breathing, pain, anxiety, and fever

Question 22

Which antibiotics should be administered to infants <3m with sepsis?

Answer 22

Ampicillin (75 mg/kg/dose) + Cefotaxime (100 mg/kg/dose, MAX 2 g/dose)

Question 23

Which antibiotics should be administered to patients >3m with sepsis?

Answer 23

Ceftriaxone (100 mg/kg/dose, MAX 2 g/dose) IV q24h

Add Vancomycin if suspect meningitis (15 mg/kg/dose, MAX 1 g/dose) IV q6h

Question 24

Why is cefotaxime preferred to ceftriaxone in infants <3m?

Answer 24

Ceftriaxone is highly bound to albumin and appears to displace bilirubin
Although displacement of free bilirubin by ceftriaxone has not been reported, it is advisable to avoid ceftriaxone in neonates at risk for acute bilirubin encephalopathy.

Question 25

Which vasopressor should be given in pediatric septic shock?

Answer 25

Depends on whether the patient presents with warm or cold shock Early distributive shock in children often presents as warm shock Give norepinephrine (true vasopressor, squeezes the pipes) ``` Later distributive shock often presents as cold shock Give epinephrine (inotrope, squeezes the pump but not the pipes) ```

Question 26

What is the dose of norepinephrine in pediatric septic shock?

Answer 26

Consult Pedi STAT 0.1 mcg/kg/minute to 2 mcg/kg/minute usual maximum dose: 2 mcg/kg/minute

Question 27

What is the dose of epinephrine in pediatric septic shock?

Answer 27

Consult Pedi STAT 0.1 to 0.5 mcg/kg/minute Rates >0.3 mcg/kg/minute associated with vasopressor activity

Question 28

A patient with suspected sepsis has persistent shock despite adequate fluid resuscitation and the addition of vasopressors. What is the next step in management?

Answer 28

Consider stress dose hydrocortisone A child in septic shock with fluid-refractor and vasopressor-refractory shock may have concomitant adrenal insufficiency Administer hydrocortisone 1-2mg/kg IV bolus (mas 100mg)

Question 29

Which metabolic derangement is commonly seen in pediatric septic shock?

Answer 29

Hypoglycemia

Question 30

How do you calculate maintenance fluids in children?

Answer 30

There is a section for this in Pedi STAT Otherwise, can use "4-2-1 rule" 4cc/kg or 1st 10kg 2cc/kg for 2nd 10kg 1cc/kg for every kg over 20kg

Question 31

How should hypoglycemia be corrected in pediatric patients?

Answer 31

Consult Pedi STAT Use D10W in all pediatric patients "preference for larger volumes of less-concentrated dextrose to reduce venous injury" UTD" "Higher concentrations of dextrose are not recommended as an initial bolus, as they frequently result in hyperglycemia with a subsequent insulin surge, triggering further hypoglycemia." Dosing as per Pedi STAT = 5cc /kg Alternatively you can use the "rule of 50s" Neonates and infants should be given 10% dextrose at 5 mL/kg IV bolus, toddlers and children should receive 25% dextrose at 2 mL/kg IV bolus, and adolescents can be given 50% dextrose at 1 mL/kg IV bolus