2c Respiratory Diseases (Apnea of Prematurity) Yen

Question 1

What is an overview of Apnea?

Answer 1

Occurs in 25% of preterm infants. Contributes to prolonged hospitalization. Frequency decreases with increasing maturity

Question 2

What is the frequency of apnea like in premature infants?

Answer 2

Nearly 100% < 28 weeks. 50% 30-31 weeks. 14% 32-33 weeks. 7% 34-35 weeks

Question 3

What is the definition of apnea?

Answer 3

The cessation of respiratory airflow for more than 20 seconds. Short pauses in breathing (5-10 sec) is normal in premature infants. Clinically presents few days after respiratory support removed. Usually accompanied by bradycardia and/or cyanosis

Question 4

What is Central Apnea?

Answer 4

Absent inspiratory effort (no signal from the brain to breath)

Question 5

What is Obstructive Apnea?

Answer 5

Has inspiratory effort, airway obstruction present

Question 6

What is the Pathogenesis of Apnea?

Answer 6

Poor central respiratory drive (immature chemoreceptor function). Upper airway patency (poor pharyngeal muscle tone). Inadequate respiratory muscles (decreased contractile strength). Environmental temperature (more apneas with increased ambient temperature). Nasal obstruction (Obligate nose breathers, they do not switch to oral breathing during nasal occlusion)

Question 7

What is the diagnosis for Apnea?

Answer 7

Diagnosis of Exclusion. Other conditions that can cause apnea: Infection, Hypoxemia, Temperature instability, Metabolic disorders, Intracranial hemorrhage, Antepartum medications (Mg sulfate, Opiates)

Question 8

What are the general measures for Apnea management?

Answer 8

Servo-controlled warmer or incubator. Avoid vigorous nasal suctioning or irritating stimuli (can cause inflammation). Supplemental oxygen. Nasal CPAP (Continuous Positive Airway Pressure)

Question 9

What is the pharmacologic class of choice for Apnea?

Answer 9

Methylxanthine therapy

Question 10

What is the MOA of Methylxanthine?

Answer 10

Increases ventilatory response to CO2. Increase force of diaphragmatic contraction. Improves pharyngeal muscle tone. Reduced duration of REM sleep

Question 11

What is the Methylxanthine agent used?

Answer 11

Theophylline

Question 12

What are the target serum levels with Theophyline?

Answer 12

7-12 mcg/ml

Question 13

What are the ADRs with Theophylline therapy?

Answer 13

Tachycardia, GI irritation (causes reflux), feeding intolerance, vomiting, irritability, jitteriness, seizures

Question 14

When is Caffeine used for Apnea?

Answer 14

Continue use until 34-36 weeks GA, and apnea resolved for at least 5 days. Therapeutic range of 5-25 mcg/ml

Question 15

What are the three agents used to treat apnea of prematurity?

Answer 15

Theophylline. Caffeine. Doxapram (not routinely used)