Postanesthetic Apnea in the Former Preterm Infant Flashcards by Cindy Ehret

After an anesthetic, former premature infants should be admitted to the hospital overnight for cardio-respiratory monitoring. True or false?

True.

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What is the incidence of apnea for premature infants:

< 30 weeks gestation
30-31 weeks
34-35 weeks

80%

50%

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What are contributing factors causing apnea due to prematurity? (4)

CNS disease
Systemic illness
Thermal/metabolic disturbances
A/w anomalies

CAST

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What are the types of apnea? (3)

Central: no nasal airflow, no muscular activity

Obstructive: no nasal airflow WITH muscular activity

Mixed

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What is the correlation between a preterm infant and brainstem conduction time?

Immature infants have increased brainstem conduction time.

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For an infant that is ~28 weeks preterm, the age at last day of apnea is generally around _____.

2 months

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For an infant that is ~29 weeks preterm, the age at last day of apnea is about _____.

1 month

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How is ventilation generally regulated? (3)

Central rhythm (pattern) generator

Central chemoreceptors (CO2) not fully developed in pre-term

Peripheral chemoreceptors (O2) not fully developed in pre-term

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What is the ventilatory response to CO2 in preterm infants? (4)

Flatter response

Flatter at 2 days postnatal age than at 4 weeks

Flatter in preterms with apnea than those without

Flatter during hypoxia than during normoxia or hyperoxia

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What is the ventilatory response to hypoxia for term and preterm infants? (3)

Increase followed by sustained decrease
Reverse response to hyperoxia
Initial increase blunted in preterms

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When is a sustained increase response seen in

term infant
preterm infant

1 week

3 weeks

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What is the pre-term’s response to hypoxia?

Initial increase
Then, sustained decrease until see 100% O2

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What can affect upper airway function and induce apnea? (3)

Irritants can induce reflex apnea

Intrinsic upper airway instability

Delayed chemoreceptor activation of upper airway muscles relative to diaphragm

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Suction can cause apnea without having an anesthetic because of reflexes. True or false?

True.

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What are the effects of halogenated anesthetics? (4)

Decreased muscle tone of airway

Reduced FRC

Dose dependent decrease in CO2 response & right shift of CO2 response curve

Depress response to hypoxia (even at subanesthetic doses)

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What minimum MAC results in a decreased response to hypoxemia with halogenated agents?

1/10 MAC

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Increased incidence of apnea in infants < ____ weeks so don’t let kids go home < _______ weeks.

What is a risk factor in itself for predicting apnea?

anemia

Strict regional is _______ against apnea.

If regional is combined with any type of anesthetic, what occurs?

PROTECTIVE, but does not rid risks of apnea

Back to same risks as general if not worse.

The use of ketamine with a spinal in an apneic risk infant will decrease risk of apnea. True or false?

False

What can help with bradycardia and O2 saturation?

Caffeine

What are general pediatric recommendations for surgery? (4)

Delay elective surgery beyond 46 weeks post-conception

Hospitalize < 52 weeks post-conception

Consider caffeine prophylaxis

Consider use of STRICT regional anesthesia

Pyloric stenosis is a surgical emergency. True or false?

False.

When should infants with pyloric stenosis present to the operating room? (2)

Adequately hydrated

Electrolytes normalized

What is the great risk for hypertrophic pyloric stenosis infants?

ASPIRATION

What is hypertrophic pyloric stenosis? What occurs as a result?

Hypertrophy of the muscular layer of pylorus Gastric outlet obstruction

What is the M:F ratio of occurence of hypertrophic pyloric stenosis?

4:1 male:female

What predisposes an infant to have hypertrophic pyloric stenosis?

family history Otherwise, unknown etiology.

How does hypertrophic pyloric stenosis present? (5)

Recurrent projectile vomiting Palpable "olive" in the epigastrum Visible peristalsis Bradypnea Jaundice

When does hypertrophic pyloric stenosis present?

2 - 6 weeks of age

How is hypertrophic pyloric stenosis confirmed? (2)

Barium swallow Ultrasound

What are anesthetic considerations for hypertrophic pyloric stenosis? (3)

Risk of aspiration Dehydration Metabolic derangements

What are signs of dehydration in infant with hypertrophic pyloric stenosis when there is\_\_\_% dehydration: 5 10 15 20

poor tissue turgor, dry mouth sunken font, tachycardia, oliguria sunken eyeballs, hypotension stupor,coma

If HCO3 \> \_\_\_\_, more indication of vomiting and dehydration. What situation can result?

30 Hypochloremic metabolic alkalosis. Hypokalemia also.

Urine becomes acidotic as ____ stores are depleted. As a result the body saves ____ and ______ while excreting \_\_\_\_\_. What is the resulting pH of the urine?

K+ stores Na, H2O and excretes H+ ACIDIC

How do you preoperatively replace fluid deficits?

D5 ½ NS + 20-40 meq/L potassium

What are the goals for the following electrolytes? Cl HCO3

Cl \> 90 HCO3 \< 30

What is the anesthetic management for pyloric stenosis? (4)

Suction stomach Preoxygenate RSI or awake Maintain with N2O, unless lap.

What should you avoid in pyloric stenosis?

NARCOTIC

When should you extubate in an infant with pyloric stenosis?

AWAKE