Peds

Question 0

What is the earliest age at which preoperative anxiolysis may be used? What is the oral dose of Midazolam?

Answer 0

Separation anxiety does not begin to develop until after 6 months of age

Oral dose of Midazolam is 0.5 mg/kg

Question 1

What is the concentration of fetal hemoglobin at birth? When does it reach it’s lowest levels?

Answer 1

At birth, the concentration of hemoglobin F is about 80%

It reaches it’s lowest levels by 2 to 3 months of age

Question 2

List 5 fundamental differences between the adult and neonate airway

Answer 2

The tongue of an infant is much larger than an adult
- increased risk of obstruction and difficulty visualizing the larynx

Larynx is located more cephalad (C3-C4) in neonates compared with adults (C4-C5)
- more anterior view during direct laryngoscopy

Infant epiglottis is narrow and omega-shaped compared with broad and flat in adults
- can create difficulty during laryngoscopy

Vocal cords are angulated in neonates compared with being perpendicular to the trachea in adults
- can cause difficulty with intubation

Larynx is funnel-shaped in neonates with the cricoid being the narrowest part, while adults have a cylindrical larynx with the glottis opening being the most narrow area

Question 3

How high can fetal PaO2 rise when the mother is given 100% supplemental O2?

Answer 3

Fetal PaO2 does not rise above 45 mm Hg, even when 100% O2 is given to the mother, because of the high O2 consumption of the placenta, and the uneven distribution of maternal and fetal blood flow in the placenta

Question 4

What is usually the first sign of a high spinal in infants?

Answer 4

Respiratory depression (apnea and hypoxia)
- requires immediate intubation

Hypotension, 2/2 loss of sympathetic tone, is rarely seen in children under 5 years old

Question 5

What gestational age is most at risk for retinopathy of prematurity? What is it’s mechanism? How can it be avoided?

Answer 5

ROP typically occurs in newborns who are born less than 35 weeks of age
- risk is negligible after 44 weeks

Mechanism:

• Hyperoxia leads to constriction of the retinal arterioles, resulting in swelling and degeneration of endothelium that disrupts retinal development
• When normoxic conditions return, vascularization resumes abnormally, causing scarring of the retina

Exposure if preterm infants to PaO2 greater than 80 mm Hg or prolonged periods of time should be avoided
- maintain saturation between 93 and 95% in premature newborns

Question 6

At what pressures do you want an endotracheal air leak in children? How do you test for it?

Answer 6

There should be a small air leak around the endotracheal tube at peak inflation pressures of approximately 15 to 25 cm H2O.

The test can be performed by slowly increasing the airway pressure and listening with a stethoscope over the larynx to hear when a leak develops.

Question 7

How can you estimate the appropriate depth of insertion of an ETT in a child?

Answer 7

For children over three: Age/2 + 12

Question 8

A baby with an omphalocele should be evaluated for what other disorder?

Answer 8

Congenital heart disease

- occurs in up to 20% of patients with an omphalocele

Question 9

Why do infants and children require higher doses of succinylcholine compared to adults?

Answer 9

Increased extra cellular fluid increases the volume of distribution

Question 10

What is the usual timing of diagnosis of pyloric stenosis? What type of electrolyte abnormality is it associated with? What is the correct fluid resuscitation? How do you know when a child is optimized for surgery?

Answer 10

Usually diagnosed at 2 to 6 weeks of age

Associated with a hypochloremic, hypokalemic metabolic alkalosis

Resuscitation involves replacement of deficit with NS followed by maintenance fluid at 1.5 times normal without potassium

Semi-normalization of chloride (over 100) may be the best suggestion of optimization
- pH and K are not reliable indicators

Question 11

What is the most common cause of neonatal bradycardia (

Answer 11

Respiratory failure leading to hypoxia and acidosis

Question 12

What is the correct energy level when using a manual defibrillator in a pediatric patient?

Answer 12

Initial shock should be 2 J/Kg followed by 4 J/Kg for initial shocks

Question 13

The spinal cord of newborns extends down to what level?

Answer 13

L3

Question 14

When does the pulmonary vascular resistance of newborns decrease to that of adults?

Answer 14

2 to 3 months

Question 15

Which pediatric patients are at risk for post-op apnea and must be admitted for observation? What type of anesthetic is preferred? What can be given to decrease risk? What if an infant already has a history of apnea/bradycardia?

Answer 15

Infants younger than 60 weeks post-conceptional age
- anemia is an additional risk factor

Spinal should be considered over GA, although regional plus sedation incurs same risk as GA

Caffeine administration has been shown to decrease risk

In an infant with a prior history, it is recommended to have a six-month interval free from any events before proceeding with elective surgery

Question 16

At what age is the MAC requirement the highest?

Answer 16

3 months

Question 17

Describe Down syndrome

Answer 17

Caused by trisomy 21

Features:
Congenital cardiac defects (commonly endocarditis cusion defects)
Short neck
Small mouth
Large tongue 
Thyroid dysfunction 
Atlanto-occipital instability

Question 18

What are some possible manifestations of hypothermia in infants?

Answer 18

Increased total body O2 consumption
Metabolic acidosis 
Hypoglycemia 
Delayed awakening 
Prolonged duration of muscle blockade 
Depression of ventilation

Question 20

When taking care of a child with a myelomeningocele, what else should you consider?

Answer 20

Other pathologies associated with myelomeningocele:

• Hydrocephalus
• Congenital heart defects
• Short trachea - increased chance of bronchial intubation
• Latex allergy

Question 21

What is the normal dose for caudal anesthesia in children? Are there any risks?

Answer 21

1 mL/kg of 0.25% Bupivacaine can generally cover procedures in the T10-S5 dermatomes (no difference between 0.125% and 0.25% Bupi)

Higher risk of dural puncture in infants than adults as the dural sac extends to the S3/4 level instead of S1 as in adults

Question 22

What are some anesthetic associations with rare pediatric syndromes?

Answer 22

Klippel-Feil - cervical spine fusion

Down syndrome - endocardial cusion defects, atlanto-axial instability, subglottic stenosis

Beckwith-Wiedmann - hypoglycemia

Pierre-Robin - micrognathia, upper airway obstruction

Question 23

Describe epiglottitis

Answer 23

An airway emergency that usually occurs in children aged 2-5 years

Caused by Haemophilus influenzae type B

Signs and symptoms include fever, profuse drooling, stridor, and inability to lay supine
- characteristic radiology finding is the “thumb sign” which shows swollen epiglottis along with prevertebral edema

Treatment includes ENT consult, early intubation, and antibiotics
- no attempts at stimulation or suction should be made

Anesthetic management should include sevoflurane inhaled induction in the sitting position, maintenance of CPAP during spontaneous ventilation, and avoidance of paralysis

Question 24

Describe croup

Answer 24

Also called laryngotracheobronchitis

Usually caused by the parainfluenza virus

Signs and symptoms are viral prodrome, fever, and barking cough
- characteristic radiology finding is the “steeple sign” showing only mucosal edema

Treatment includes racemic epinephrine

Question 25

What is the most important mechanism of heat generation in neonates/infants? What triggers it? What inhibits it?

Answer 25

Nonshivering thermogenesis from brown fat

Triggered by norepinephrine, glucocorticoids, and thyroxin

Inhibited by inhaled anesthetics and B-blockers

Question 26

At what rate and what type of solution should initial IV fluid resuscitation in children be?

Answer 26

20 mL/kg of normal saline WITHOUT potassium

Question 27

What pain medication is contraindicated in children following tonsillectomy? Why?

Answer 27

Codeine

- has been linked to several pediatric deaths, likely in “over-metabolizers”

Question 28

What is prostaglandin E1 used for in neonates? What are the side effects?

Answer 28

PGE1 is used to maintain patency or reopen the ductus arteriosus in “ductal dependent lesions” to improve flow to either the lungs or systemic circulation

Side effects include:

• apnea
• hypotension (decreases both SVR and PVR)
• fevers
• CNS irritability

Question 29

Why do infants have an increased work of breathing relative to adults? Why do they fatigue quicker?

Answer 29

Increased work of breathing due to:

• smaller airways cause increased resistance
• increased O2 consumption per kilo
• highly compliant chest wall leading to functional airway closure with each breath

Due to decreased proportion of diaphragmatic type I muscle fibers, infants are more susceptible to early fatigue

Question 30

Compared to adults, why is induction of anesthesia in infants quicker?

Answer 30

4 main factors allow a more rapid rise of FA:FI

1) Infants have increased minute ventilation relative to FRC
2) Infants have a greater fraction of cardiac output that is distributed to vessel-rich organs
3) Infants have decreased blood:gas coefficients
4) Infants have decreased tissue:blood coefficients

Question 31

What is the treatment of choice for intra-op hypotension in a neonate and why?

Answer 31

Atropine is the initial treatment of choice

Neonatal myocytes have poor lusitropy and cannot accomodate increases in preload

Myocytes are also insensitive to catecholamines, so perssors are ineffective

Question 32

Describe the benefits of parental presence during induction of anesthesia (PPIA). How effective is it?

Answer 32

PPIA can help reduce the anxiety of a child (and possibly the parent) during induction of anesthesia

It is most beneficial when a calm parent accompanies the child
- anxious parents can worsen a child’s anxiety

PPIA is still less effective than PO Midazolam