Apnea in the Newborn

Developed by - Lisa Fikac, RNC-NIC, MSN

Original Author - Stacey Cashwell, MSN, RN Expiration Date - 1/27/17

This continuing education activity is provided by Cape Fear Valley Health System, Training and Development Department, which is an approved provider of Continuing Nursing Education by the North Carolina Nurses Association, an accredited approver by the American Nurses Credentialing Center’s Commission on Accreditation.

0.9 Contact hours will be awarded upon completion of the following criteria:

• Completion of the entire activity • Submission of a completed evaluation form • Completion a post-test with a grade of at least 85%.

The planning committee members and content experts have declared no financial relationships which would influence the planning of this activity.

Microsoft Office Clip Art is the source for all graphics unless otherwise noted.

• Discuss the physiology and risk factors leading to apnea in the newborn. • Discuss assessment of the newborn with apnea to include history, physical assessment,

and diagnostic studies. • Discuss the management and outcomes of the newborn with apnea.

Apnea is one of the most frequent respiratory problems in preterm infant.

• The reason why some infants are affected and others are not is unknown. • Apnea in the term infant is never normal and must be thoroughly assessed.

Respiratory Physiology

There are two major mechanisms that control and regulate ventilation. They are the -

• Neural system • Chemical system

Neural System

The cerebral cortex and brainstem control the neural system.

• They regulate respiratory rate and rhythm.

The peripheral components of this system are found in the upper airway and lungs.

Chemical System

The chemical control system is found in the medulla and is sensitive to PaCO2 changes.

• The peripheral portion of the system is in the carotid and aortic vessels and is also sensitive to PaCO2 changes.

• This system also controls alveolar ventilation which is the primary defense against hypoxia.

The adult response to hypoxemia and carbon dioxide retention is to increase respirations.

• However, the neonate responds to this same scenario by an initial increase in respirations followed by respiratory depression.

The preterm infant is less responsive to carbon dioxide. This may be due to -

• Decreased sensitivity in the chemical center • Mechanical factors that prevent an increase in ventilation

Key Terms -

Apnea - a respiratory pause of at least 20 seconds or shorter IF accompanied by cyanosis, pallor, hypotonia, or bradycardia.

Periodic breathing - a sequence of 3 or more successive respiratory pauses of > 3 seconds in duration, with < 20 seconds of normal respiratory pattern between pauses.

• In term infants, a limited amount of periodic breathing is considered normal.

• Periodic breathing is less frequent after 36 weeks gestation. • In preterm infants, periodic breathing is frequently the cause of prolonged oxygen desaturation.

Primary apnea is the cessation of breathing following rapid attempts to breathe.

• This is the first sign of oxygen deprivation. • It is usually related to labor and delivery events. • It is difficult to differentiate between primary and secondary apnea.

o Assume that the infant is in secondary apnea if there is any doubt. • Bradycardia develops at the same time the infant enters primary apnea. • BP is maintained. • When in primary apnea, the infant responds to -

o Tactile stimulation such as drying or slapping the infant's feet o Free flow oxygen

Secondary apnea occurs when oxygen deprivation continues.

• Following several gasps, breathing stops. • Bradycardia will progress to asystole. • The BP falls as secondary apnea begins. • When in secondary apnea -

o Tactile stimulation will not help.

o Positive-pressure ventilation is necessary.

Remember -

• If an infant begins breathing with stimulation, he is in primary apnea. • If an infant does not begin breathing with stimulation, he has secondary

apnea and will require positive-pressure ventilation (PPV). • The longer a baby remains in secondary apnea, the longer it will take for

spontaneous breathing to occur. • Initiation of PPV results in rapid improvement in the compromised infant--don't waste time

continuing to stimulate the infant. • Knowledgeable and skilled caregivers capable of responding to events surrounding birth should

be present at every delivery.

Apnea of prematurity is a form of primary apnea and is not associated with any other disease processes.

There is an inverse relationship between apnea and gestational age.

• The lower the gestational age, the greater the incidence of apnea. • At least 85% of infants less than 34 weeks gestation experience apnea of

prematurity.

Apnea and bradycardia episodes usually begin within the first week of life and spontaneously resolve by 36 weeks postconceptional age.

• For ~95% of infants, episodes of apnea resolve by term.

Apnea of prematurity may be associated with -

• Obstruction o Accounts for up to 30% of cases

• Hypoxemia • Neuronal immaturity • Sleep • Catecholamine deficiency • Respiratory muscle fatigue

Various conditions that produce hypoxemia and/or alter the sensitivity of peripheral or central chemoreceptors may cause apnea in the preterm infant.

Neuronal immaturity is a logical source for apnea because respiratory effort is more immature at younger gestational ages.

• This is due to a lack of dendrite formation and limited synaptic connections. This results in a decreased excitatory drive.

Etiologies of apnea include -

• Central causes • Obstruction • Mixture of central and obstructive causes

Central apnea is a total absence of airflow and respiratory effort.

• This accounts for ~15% of all apnea. • Contributing factors may include -

o Increased chest wall compliance combined with less compliant lungs o Altered levels of neurotransmitters in the brain stem o Diaphragmatic fatigue o Central nervous system (CNS) insult o Unknown reasons

Obstructive apnea is an absence of air flow with continued respiratory effort associated with a blockage.

• Obstruction is usually at the level of the pharynx. • This accounts for as much as 30% of all apnea. • Related to -

o Flexion of the neck o Secretions or formula in the airway o Occluded endotracheal tube o Macroglossia - large tongue o Micrognathia - small lower jaw

Mixed apnea is a combination of central and obstructive apnea.

• This accounts for 50-60% of all apnea.

Specific Causes of Apnea

Sleep related

Apnea is more frequent during sleep and especially during rapid eye movement (REM) or active sleep.

Preterm infants, especially those less than 32 weeks gestation, spend ~80% of their time asleep.

• The majority of that time is spent in REM sleep.

Apnea is uncommon during non-REM sleep, but periodic breathing is much more common.

Potential respiratory system causes of apnea include -

• Hypoxia • Respiratory distress syndrome (RDS) • Aspiration of -

o Formula o Blood o Secretions

• Infection - e.g. pneumonia • Pneumothorax • Airway obstruction

o Airway anomalies (e.g. choanal atresia) o Secretions

Potential cardiovascular system causes of apnea include -

• Hypotension • Arrhythmias • Patent ductus arteriosus (PDA) • Congestive heart failure (CHF)

Potential hematologic system causes of apnea include -

• Anemia where there is insufficient hemoglobin to carry oxygen.

• Polycythemia slows delivery of oxygen to the cells due to thickness of the blood.

Thermoregulation issues that may cause apnea include -

• Hypothermia - very common • Hyperthermia • Rapid rewarming of the cold infant • Increased environmental temperature

Types of infection that may cause apnea include -

• Pneumonia • Sepsis - bacterial or viral • Meningitis • Necrotizing enterocolitis (NEC)

Metabolic factors that may cause apnea include -

• Hypoglycemia • Hypocalcemia • Hypomagnesemia • Hyponatremia • Acidosis

Gastrointestinal factors that may cause apnea include -

• Vagal stimulation which may occur with feeding or stooling • Gastroesophageal reflux (GER) - may be a factor due to lower

esophageal sphincter relaxation, but recent studies do not find an association between pre-discharge apnea and reflux.

• Gastric distention

Iatrogenic causes of apnea include -

• Increased environmental temperature • Vagal response to suctioning or insertion of gavage tubes • Painful stimuli • Medications used in the mother -

o Narcotics o Analgesics o Anesthesia o Magnesium sulfate

• Medications used in the infant - o Phenobarbital o Prostaglandin E1 o Fentanyl (Sublimaze®) o Morphine sulfate o Midazolam (Versed®) o Lorazapam (Ativan®)

Assessment and management of apnea should start with the simple and obvious and then move on to the unclear and complex.

Evaluation of apnea should focus on ruling out treatable causes.

Assessment

Assess the circumstances surrounding the apnea episodes.

EXAMPLES

• Apnea that occurs soon after birth may be associated with medications given to the mother.

• Does apnea always occur after feedings? o Consider changes in feeding amounts, method, or frequency

• Associated bradycardia, color change, or desaturations • Duration • Position of the infant • Type of stimulation needed to resolve the episode

o None, self-resolved o Gentle tactile stimulation o Vigorous tactile stimulation o Oxygen o Positive pressure ventilation

Once the simple and straightforward factors have been ruled out or corrected, then evaluate the more complex factors.

Go from the routine to the unusual and complex!!!

Assess the history for risk factors -

• Perinatal - maternal factors o Maternal bleeding o Drugs o Fever o Hypertension

o Prolonged rupture of membranes o Polyhydramnios o Chorioamnionitis o Decreased fetal movements o Abnormal fetal presentation

• Neonatal o Prematurity o Cardiorespiratory disease o Metabolic abnormalities o Temperature instability o Infection o Environmental causes o CNS disorders

Physical assessment includes -

• Complete physical and neurological exam o Particularly tone and posturing

• Assess for congenital malformations o Especially those involving the airway

• Assess for respiratory distress and signs of congenital heart disease • Assess the abdomen for potential impact on respirations

Laboratory Studies

• CBC to evaluate for potential infection and anemia • Cultures to rule out sepsis

o Blood o Urine o Cerebrospinal fluid (CSF)

• Glucose and electrolyte levels to assess for metabolic causes • Blood gases to assess for hypoxemia and metabolic and/or respiratory factors

Other Studies

• Chest X-ray to assess for cardiac and respiratory causes • Echocardiogram to assess for cardiac abnormalities • Head ultrasound to assess for intraventricular hemorrhage (IVH) or structural abnormalities • Upper GI to evaluate for gastroesophageal reflux (GER) • EEG to evaluate for further neurological causes

The goals for treatment and management of secondary apnea are to diagnosis the specific cause and treat it.

When treating primary apnea, or apnea of prematurity, treatment should begin with the least invasive interventions possible.

Interventions should begin with the following and progress to the subsequent levels -

• Gentle tactile stimulation o This is helpful when apnea is immediately recognized and treated.

• Positive pressure ventilation (PPV) • Oxygen approximating the FiO2 used before the spell but not exceeding a 10% increase over that

baseline level. o This helps to prevent complications from oxygen toxicity.

• Continuous positive airway pressure (CPAP) may be needed for infants who do not respond to lesser interventions or who have repeated, prolonged spells.

• Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) is a useful way to augment CPAP for infants with severe apnea

o This combines nasal CPAP with the delivery of neurally synchronized breaths through the nasal prongs.

• Mechanical ventilation may be needed for those infants where CPAP nor NIV-NAVA does not improve apnea episodes.

Avoid possible apnea triggers such as -

• Vigorous suctioning • Hot or cold to the face • Sudden gastric distention • Painful stimuli • Loud noises

Positioning -

• Prone positioning may help the infant with apnea.

o It is associated with - Higher oxygen saturation Shorter gastric emptying time Decreased GER and aspiration

• Position the infant with the neck in a neutral position. o Positioning aids may be used.

Pharmacologic Therapy

Methylxanthines are also used to treat apnea of prematurity but should only be used when pathologic causes have been ruled out.

• Methylxanthines work primarily through central stimulation rather than by changing pulmonary function.

The two most commonly used methylxanthines are -

• Caffeine citrate • Theophylline

Side effects of methylxanthines include -

• Gastric irritation • Hyperactivity - restlessness, irritability • Myocardial stimulation - tachycardia, hypotension • Increased urine output

Caffeine citrate is the drug of choice because -

• It may be given once or twice a day. • The onset of action is sooner. • The therapeutic blood level range is wide. • Side effects are less than theophylline.

Caffeine citrate -

• Causes smooth muscle relaxation. • Increases skeletal muscle tone. • Stimulates the respiratory center of the brain. • Increases minute ventilation. • Decreases the CNS threshold to carbon dioxide. • Increases the CNS response to hypercapnea. • Decreases diaphragmatic fatigue. • Increases the metabolic rate.

o Increases oxygen consumption.

Parent Teaching

Apnea episodes can be very upsetting to parents and stand as a barrier to bonding.

• Parents are often concerned that their baby will experience apnea episodes once they go home.

• Teaching parents about the etiology of and response to apnea spells is essential.

• Teaching parents helps to alleviate their fears and involve them in caring for their baby.

Most infants are allowed to mature and out-grow their apnea spells. However, some infants may need to be discharged to home with an apnea monitor.

• If their baby is discharged on a monitor, parents need to be taught how to - o Operate the monitor. o Appropriately respond to the baby's condition.

This includes instructing caregivers on how to perform CPR.

Parents also need to learn how to recognize when their baby is getting sick or experiencing a change in respiratory status.

• This includes when to seek additional healthcare from the baby's provider.

Outcomes depend on the underlying cause of the apnea episodes.

• In infants who are otherwise healthy, the prognosis is good. • For infants who continue to experience apnea spells after reaching 37 weeks

postconceptional age, there is a higher risk for airway and/or neurodevelopmental problems.

• Prompt recognition of apnea episodes and intervention decrease the possibility of complications from hypoxia.

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