Pediatrics - Pyloric Stenosis & Neonatal Apnea Flashcards Preview

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Flashcards in Pediatrics - Pyloric Stenosis & Neonatal Apnea Deck (34):
1

What is the incidence of apnea of prematurity when the child is less than 30 weeks gestation?

80%

2

What are some contributing factors to apnea of prematurity?

CNS disease, Systemic illness, thermal/metabolic disturbances, airway anomalies

3

What are the 3 patterns of apnea?

Central: no airflow at nares and no muscular activity

Obstructive: muscular effort without nasal airflow

Mixed

4

How is ventilation regulated?

Central rhythm (pattern) generator--root cause
Central chemoreceptors (CO2)
Peripheral chemoreceptors (O2)

5

What are some possible causes of a less pronounced (flatter) CO2 response curve?

Prematurity
Flatter at 2 days than at 4 weeks postnatal age
Flatter in preterms with apnea than those without
Flatter during hypoxia

6

What is the premature infants ventilatory response to hypoxia?

Initial increase followed by a sustained decrease

7

At what age does the sustained increase ventilatory response mature?

At 1 week in term infants and about 3 weeks in preterm infants

8

What enhances the initial increase in ventilation?

CO2

9

What effects do halogenated anesthetics have on FRC and muscle tone?

Reduced FRC
Decreased muscle tone of airway, chest wall and diaphragm

10

What effect do halogenated anesthetics have on the CO2 response curve?

Dose-dependent decrease in slope and right shift of CO2 response curve

11

What effect do halogenated anesthetics have on the ventilatory response to hypoxia?

Depress ventilatory response to hypoxia (even at sub anesthetic doses)

12

What is the post conceptual age?

Age since birth - weeks premature

13

What type of pharmacological prophylaxis could potentially be used to help with AOP?

Caffeine (not routinely used, but helpfun)

14

What are the recommendations for elective surgery for patients with AOP?

Delay elective surgery beyond 46 weeks post conceptual age

15

At what age should infants be hospitalized and monitored with AOP?

<52 weeks PCA

16

What type of emergency is pyloric stenosis?

Medical, not surgical

17

Infants with pyloric stenosis should present to the operating room only after what has been normalized?

Adequate rehydration and normalized electrolytes

18

Patients with pyloric stenosis are treated as at risk for what?

Aspiration

19

What causes pyloric stenosis?

Hypertrophy of the muscularis layer of the pylorus

20

What is the incidence of pyloric stenosis?

1:300-500 live births
4:1 male to female

21

At what age does pyloric stenosis typically present?

2-6 weeks

22

How does pyloric stenosis present?

Recurrent vomiting
Varying degree of malnutrition/dehydration
Palpable "olive" in the epigastrium
Visible peristalsis
Bradycardia
Jaundice (5-10% of cases)

23

How is pyloric stenosis confirmed?

Barium swallow or ultrasound

24

What are the three main anesthetic considerations for a patient with pyloric stenosis?

Aspiration risk
Dehydration
Metabolic derangements

25

What are the physical findings for 5% dehydration?

Poor tissue turgor, dry mouth

26

What are the physical findings for 10% dehydration?

Sunken fontanelle, tachycardia, oliguria

27

What are the physical findings for 15% dehydration?

Sunken eyeballs, resting hypotension

28

What are the physical findings for 20% dehydration?

Stupor, coma

29

What are the two main serum electrolyte disturbances associated with pyloric stenosis?

Hypochloremic metabolic alkalosis
Hypokalemia

30

What happens to urine as potassium and chloride stores are depleted?

Urine becomes more acidic

31

What are some important considerations for preoperative management of patients with pyloric stenosis?

Acute volume repletion for shock
Deficit replacement over 12-48 hours
Establish normal urine output
Normalize electrolytes

32

What is the goal for normalizing chloride and bicarbonate pre operatively?

Cl > 90
HCO3 < 30

33

How is the procedure for pyloric stenosis usually performed?

Laparoscopically

34

What are some important anesthetic management considerations for a pyloric stenosis operation?

Evacuate stomach by suction
Pre-oxygenate and RSI or awake intubation
Avoid narcotics
Extubate awake