AIR LEAKS

IN THE NEONATE Developed by - Lisa Fikac, MSN, RNC-NIC

Expiration Date - 3/9/2018

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.

1.5 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 and Creative Memories are the sources for all graphics unless otherwise noted.

The author would like to thank Stacey Cashwell for her work as original author.

• Describe the etiology of the common air leaks experienced in the neonatal population.

• Discuss the clinical presentation, management, complications, and outcomes of the neonate with an air leak.

The development of the lungs is sequential and occurs in five phases -

• Embryonic phase • Pseudoglandular phase • Canalicular phase • Saccular phase • Alveolar phase

The embryonic phase occurs between 4 to 6 weeks gestation

• The main event of this phase is formation of the proximal airway • Lung buds appear and begin to divide • The pulmonary vein appears during this phase and elongates to join the lung

buds • The trachea develops, and by the end of this period there are -

o Three divisions of primitive lobes and bronchi on the right o Two divisions of primitive lobes and bronchi on the left

The pseudoglandular phase occurs between 7 to 16 weeks gestation

• The main event of this phase is the formation of conducting airways • At this time cartilage appears, and the main bronchi develop • The tracheobronchial tree branches into the trachea and terminal bronchioles

o After this occurrence, the tree only increases in size and length without additional formation of branches

• The major lobes of the lungs are identified, and the capillary bed is formed o This connects the bronchial blood supply but does not connect with the

terminal air sacs • The connective tissue, muscle, and lymphatics are identifiable

The canalicular phase occurs between 17 to 28 weeks gestation

• The main event of this phase is the formation of the acini • During this phase, Type II alveolar epithelial cells that eventually become the

alveolar lining begin to appear • Capillaries begin to proliferate and invade the walls of the terminal airways • The airway structure changes from glandular to tubular and increases in size and

length • Lung fluid production begins during this period

o Using extrapolated data derived from studies of lambs, it is believed that the term infant secretes about 250 mL/day of lung fluid

o A reduction in amount or loss of lung fluid may result in lung hypoplasia o Lung fluid aids in the -

Development and maturation of lung cells Formation, size, and shape of the air space

• Alveolar sacs appear between 24-26 weeks gestation • Keep in mind that during this phase of development -

o There is insufficient air-blood surface area for gas exchange o Type II alveolar epithelial cells are incapable of releasing sufficient

surfactant to sustain adequate respirations

The saccular phase occurs between 29 to 35 weeks gestation

• The main event of this phase is the development of gas-exchange sites • Terminal air sacs appear as an out-pouching of the alveolar ducts, or terminal

bronchioles o The air sacs look like a "bunch of grapes" o The alveolar ducts increase in number and maturity

• Mature type II alveolar epithelial cells begin to cluster at the alveolar ducts • Capillaries and vascularization increase with the eventual fusion of the

endothelium and epithelium o This creates the blood-gas barrier needed to sustain extrauterine life

• The overall size of the lungs increases quickly • At approximately 26-28 weeks, there is sufficient differentiation in the lung

structures and cells to allow oxygen exchange to occur o In other words, extrauterine life can be sustained

The alveolar phase occurs between 36 weeks gestation and continues through postnatal life until approximately 8 years of age

• This phase is marked by the expansion of gas-exchange surface area and continued proliferation of the alveoli

• The alveolar wall and interstitial spaces become very thin, and the single capillary network comes into close proximity to alveolar membrane

Surfactant is the primary surface-active agent present in the lungs, and it greatly reduces the surface tension of water.

• Fetal lungs excrete surfactant into the amniotic fluid and can be detected during pregnancy

It is composed of the following phospholipids -

• Lecithin • Sphingomyelin • Cholesterol • Phosphatidylinositol (PI) • Phosphatidylcholine (PC) • Phosphatidylglycerol (PG)

The role of surface-active phospholipids, such as surfactant, is to -

• Line the terminal air sacs which are composed mainly of Type I and Type II pneumocytes

o Type I pneumocytes cover ~ 95% of the alveolar surface which is where gas exchange occurs

o Type II pneumocytes are greater in number but cover < 5% of the alveolar surface It is believed that surfactant is produced and secreted by these cells They first appear around 20-24 weeks gestation Surfactant is first detectable at about 25-30 seeks gestation The neonate is able to maintain alveolar stability at about 33-36

weeks gestation • Maintain alveolar stability by reducing surface tension at the air-fluid

interface o Surface tension pressures in the lungs generally cause the alveoli to

collapse

o Surface-active agents reduce the surface tension allowing the droplet to smooth to a thin film that allows the alveoli to remain open and gas exchange to occur

Surfactant is essential to normal lung function because it -

• Decreases surface tension at the end of expiration AND • Increases surface tension during inspiration, or lung expansion

Surfactant prevents atelectasis at the end of expiration and facilitates elastic recoil on inspiration, stabilizing the lungs to maintain acceptable blood gas pressures and decrease the work of breathing.

The incidence of spontaneous air leaks is approximately 1% in normal term infants. Incidence increases with -

• Respiratory distress syndrome (RDS) ~ 4% • Continuous positive airway pressure (CPAP) ~ 15% • Mechanical ventilation ~20-25%.

Regardless of the severity, air leaks may interfere with the success of other treatment strategies.

Air leaks are primarily thought to be related to -

• Increased airway pressures during resuscitation • Mechanical ventilation

There are some situations where air leaks occur spontaneously, such as -

• Uneven air distribution in the term infant • Underlying lung disease in the preterm infant

In the preterm infant, reinflation of atelectatic alveoli becomes increasingly difficult over time.

• In order to generate sufficient pressures to continually reinflate the alveoli, the infant increases his -

o Respiratory rate o Respiratory depth or work of breathing (WOB)

• Maintenance of a constant inspiratory:expiratory (I:E) pressure ratio may result in uneven reinflation of alveoli leading to -

o Minimal reinflation with some breaths o Complete reinflation with some breaths, and o Over-inflation with other breaths

• The uneven pattern stresses the alveoli walls and leads to rupture of the alveoli -> an air leak.

When alveoli rupture, escaping air may dissect following the tracheobronchial tree and accumulating in any one of the following cardiopulmonary structures -

• Mediastinum - pneumomediastinum • Pleural space - pneumothorax • Pericardial sac - pneumopericardium • Interstitial tissue - pulmonary interstitial emphysema (PIE) • Peritoneal cavity - pneumoperitoneum

Air leaks are more common in the newborn period than at any other time of life.

There are three groups of infants who are greatest risk for developing air leaks. They are -

• Healthy term infants • Infants with pulmonary disease • Infants receiving positive pressure support

o Mechanical ventilation OR o CPAP

Healthy Term Infants

At birth the term infant generates high distending airway pressures 40-80 cm H2O pressure, during the first few breaths to open and stabilize the alveoli and initiate the displacement of pulmonary fluid.

Once adequate respirations have been established, only approximately 15-20 cm H2O pressure is needed to maintain an effective airway.

Frequently the infant is asymptomatic, requiring minimal to no intervention

• Resolution usually occurs within 24-48 hours of life.

Although air leaks may be small, they may delay the establishment of adequate, effective respirations and discharge from the hospital.

Infants with Pulmonary Disease

The following pulmonary diseases can lead to an air leak -

• Respiratory distress syndrome (RDS) • Aspiration syndromes

o Meconium (MAS) o Blood o Amniotic fluid o Mucous o Feeding

• Hypoplastic lungs • Congenital lobar emphysema • Pulmonary interstitial emphysema (PIE)

For infants with RDS, high pressures are needed to open and maintain the airways for adequate ventilation and oxygenation.

• Air leaks can occur because constant pressure exerted against the alveoli wall causes it to rupture.

With aspiration syndromes, the presence of foreign material in the pulmonary system sets up a chain of events.

• During inspiration, air enters the lungs. • During expiration, the foreign material obstructs the removal of air in the distal

alveoli and smaller airways causing "air trapping." o This is called the ball-valve effect. o This occurs because the airway distends with inspiration and constricts

with expiration allowing the foreign material to obstruct the small airways. • With each subsequent breath more air is trapped and the alveoli become more

distended. • Eventually, alveolar rupture and an air leak occur.

Hypoplastic lungs have experienced abnormal growth and development.

• Similar to RDS, the lungs are stiff and non-compliant, and the same series of events noted for RDS may occur.

• Hypoplastic lungs should be considered when an infant presents with a diaphragmatic hernia or a maternal history of oligohydramnios.

Infants with congenital lobar or pulmonary interstitial emphysema require positive pressure ventilation in order to maintain adequate oxygenation.

• Again, the chain of events leading to air leaks is the same as in the case of the infant with RDS or hypoplastic lungs.

In NICUs that perform surfactant replacement therapy on a regular basis, air leaks do not commonly occur.

• However, in facilities where the procedure is done infrequently or the individuals performing the procedure have limited training, the response to surfactant therapy may be inappropriate or slow causing overdistention of the airways. This can predispose the infant to an air leak.

Infants on Positive Pressure Support

Any infant requiring positive pressure during resuscitation is at risk for developing an air leak.

• Although caregivers should be mindful of this potential complication and avoid unnecessarily high pressure, it is always important to resuscitate an infant promptly and effectively.

• The use of a T-piece resuscitator for resuscitation may help to minimize the occurrence of air leaks.

Infants on mechanical ventilation are being supported with higher than normal pressures in an effort to achieve and maintain adequate oxygenation.

• Due to the use of greater pressures, the infants are at greater risk for developing air leaks.

• Infants receiving continuous positive airway pressure (CPAP) are also at risk for developing air leaks.

For both resuscitation and use of mechanical ventilation, the common denominator is the overdistention and rupture of alveoli.

• The location of the alveolar rupture determines the location and severity of air leaks.

Clinical changes in the infant's status may go unnoticed until a sudden deterioration in status occurs.

The development of an air leak should be considered when any of the following infants experiences a sudden deterioration in status -

• The preterm infant with RDS - whether he is being treated with positive pressure support or not.

• The term or post-term infant with meconium-stained amniotic fluid. • The infant with a history of PIE or lobar emphysema. • The infant requiring resuscitation at birth. • Infants receiving CPAP or positive pressure ventilation.

Term newborns can experience asymptomatic air leaks that spontaneously resolve in approximately 24-48 hours.

Physical assessment findings include -

• Symptoms may be gradual and include increasing difficulty -

o Ventilating o Oxygenating o Perfusing

• Early clinical signs include - o Restlessness and irritability o Lethargy o Tachypnea o Increasing work of breathing with -

Grunting Nasal flaring Retractions

• Signs of sudden and severe deterioration in the infant include -

o Profound generalized cyanosis o Bradycardia o Hypotension

May be severe and accompanied by poor peripheral perfusion o Dampening of the QRS complex on the cardiorespiratory monitor o Air hunger, gasping, anxious facies o Decreased or shifted breath sounds on auscultation o Chest asymmetry o Diminished, muffled, or shifted heart sounds at the point of maximal

intensity (PMI) o Easily palpable liver and spleen o Subcutaneous emphysema o Cardiorespiratory arrest

Diagnostic studies used include -

• Arterial blood gases (ABGs) may show - o Increasing hypoxemia o Increasing hypercapnia o Persistent metabolic, respiratory, and/or mixed acidosis

• Transillumination of the chest with a high-intensity fiberoptic light may reveal hyperlucency of the affected side.

o When performing transillumination, the room must be darkened as much as possible.

o Compare each side of the chest bilaterally - From right to left Under the midclavicular area In the axillae Subcostal regions

• Chest x-ray is the best way to confirm an air leak. X-rays can provide the following information that indicates an air leak -

o An increase in lucency and size o Flattened diaphragm on the affected side o Widened intercostal spaces o Decreased or absent pulmonary vascular markings o Sharp contrast of the cardiac border and diaphragm - also known as the

sharp edge sign o With tension pneumothorax, there is -

Mediastinal shift with deviation of the trachea and heart to the opposite side

Decreased volume and increased opacity of the opposite lung o With bilateral pneumothoraces, there is a narrow cardiac silhouette

Often, the best defense is a good offense...

It makes sense that prevention of air leaks should be part of the plan of treatment.

Infants should receive the lowest amount of positive pressure possible that will produce the desired result. Strategies to help achieve this goal include -

• Clearing the airway before resuscitation • Using T-piece resuscitators or pressure gauges in resuscitation • Securing endotracheal tubes properly

In situations where the infant with an air leak is not experiencing respiratory distress or only mild symptoms, close observation may be all that is needed.

Infants who are experiencing significant respiratory distress and/or cardiovascular compromise should be treated emergently.

• Healthcare providers who are adequately trained and skilled in providing emergency care must be available in all settings that provide positive pressure ventilatory support.

• Tension pneumothoraces are considered to be an emergent crisis since tension in the chest cavity decreases lung excursion and cardiac output.

• Pneumomediastinum rarely requires treatment. • Pneumopericardium is life threatening and requires needle aspiration or

drainage to avoid cardiac tamponade.

Immediate supportive care of the infant with an air leak includes -

• Elevation of the head of bed to 30-40 degrees o Work of breathing is decreased by using gravity to -

Move air to the upper chest Push abdominal organs down and away from the

diaphragm • Administration of oxygen at 100% FiO2

o The goals for using this treatment are to - Improve oxygenation Create a nitrogen washout that will increase the

reabsorption rate of the trapped air by as much as six fold

o The prolonged use of 100% oxygen in the preterm infant should be made with extreme caution due to the risks of - Oxidative stress Development of retinopathy of prematurity (ROP)

Needle aspiration of the air leak is usually attempted first and may be all that is needed to resolve the air leak.

For infants receiving positive pressure ventilatory support, a needle aspiration kit should be easily accessible. The kit consists of -

• Antiseptic solution • 18, 20, or 22-gauge angiocath with a T-connector OR

19, 21, or 23 gauge butterfly needle

• Three-way stopcock • 20-30 mL syringe

Once the chest is cleansed aseptically, there are two approaches for needle aspiration -

• Lateral approach - recommended due to the decreased risk of hitting major blood vessels in the chest.

o The infant is positioned at a 45 degree angle with the affected side up. o The butterfly needle or angiocath is inserted into the 4th intercostal space

in the mid-axillary or anterior axillary line.

• Anterior approach o The infant is positioned supine with the head of the bed slightly elevated. o The butterfly needle or angiocath is inserted into the 2nd intercostal space

in the midclavicular line.

Once the chest has been accessed with the butterfly needle or angiocath, air is withdrawn into the syringe and released into the environment by turning the stopcock.

• The procedure is repeated until either - o There is no more air aspirated OR o A chest tube can be placed

In the event that infant fails to improve and/or air continues to re-accumulate, a chest tube should be inserted.

Chest tube insertion is a surgical procedure that requires all healthcare providers involved to practice strict sterile technique that includes use of -

• Gown • Gloves • Mask • Cap

Commercially prepared chest tube procedure trays are available and should include the following equipment -

• Gloves, gown, mask, cap • Sterile drapes • Antiseptic solution • 8, 10, or 12 Fr thoracostomy tube • Syringes • Sterile sponges • 1% lidocaine without epinephrine • Scalpel blades • Hemostat • Scissors • Needle holder • Sterile suture • Sterile connectors • Tubing • Chest tube drainage system

• Wall suction • Sterile saline solution • Sterile bio-occlusive dressing • Chest tube clamp

Steps for chest tube insertion include -

• Pain management o Provide comfort measures for the infant. o Administer fentanyl for procedural pain since it has a more rapid onset of

action than morphine. o If the infant condition allows, administration of 1% lidocaine to the

insertion site should be done. If the infant is severely unstable, the procedure should not be delayed.

• Position the infant laterally with the affected side up and at 45 degrees. • Cleanse the chest aseptically and administer 1% lidocaine locally to anesthetize

the skin. • A small incision is made at the 6th rib in the anterior axillary or mid-axillary line. • Then, a curved mosquito hemostat is used to tunnel over the top of the 5th rib

toward the 4th rib until the tip of the hemostat is in the 4th intercostal space. • Steady pressure is used to enter the pleural space.

o In order to avoid injuring the lung, blood vessels, and nerves, care must be used to stay on top of the rib and insert less than 1 cm.

o When entering the pleural space, a rush of air may be audible. • Once in the pleural space, the hemostat is spread just enough to allow insertion of

the chest tube between the hemostat tips. • The chest tube is advanced anteriorly toward the midclavicular line.

o All side holes of the chest tube must be inside the thorax. • The chest tube is sutured in to close the skin and then secured with a sterile

occlusive dressing. • The chest tube is then attached to the chest tube drainage system used by the

individual facility. o Follow manufacturer's recommendation for use. o A one-way flutter valve may be used in an emergency and/or during

transport. • A chest x-ray is performed to confirm placement of the chest tube.

o Follow-up chest x-rays are also done to evaluate resolution of the air leak.

Chest Tube and Drainage System Care

The chest tube drainage system restores negative pressure and expands the lung by removing air and fluid from the pleural space.

Most facilities use a chest tube drainage system that is a single unit divided into three chambers consisting of -

• Collection chamber • Water seal chamber • Suction chamber

The drainage system must always be securely positioned below the level of the infant's chest. This prevents water from being pulled into the pleural space.

Patency of the chest tube, fluctuation, and bubbling should be assessed and charted hourly.

When assessing function of the chest tube drainage system, oscillation of fluid in the tube indicates that there is effective communication between the pleural space and the drainage chamber.

• In the very small infant, this may appear as a small fluctuation rather than an oscillating movement.

• Both the tubing and collection chamber should be assessed for fluctuation. • Fluctuation may stop as a result of -

o Obstruction of the tube by fibrin or blood clots o Kinked tubing o Improperly functioning suction

• Milking and stripping of the tubing generate high pressures that may damage the lung. Therefore, this should not be done.

Bubbling in the collection chamber indicates that air is being removed from the pleural space.

• Continuous bubbling may indicate a leak in the system.

• Excessive or insufficient fluid in the drainage system may inhibit proper function.

In order to maximize drainage and lung re-expansion, the infant must be turned frequently.

• Stabilization of the chest tube is vital for - o Optimal function o Comfort of the infant o Prevention of accidental removal

• The chest tube may be secured by - o Applying adhesive tape to tubing o Placing a safety pin through the tape, not the chest tube o Pinning it to the bed

If the chest tube becomes dislodged, pressure should be applied to the site with sterile gauze until the chest tube can be replaced.

Removal of the Chest Tube

Criteria for removal of the chest tube include -

• Cessation of bubbling for at least 24 hours • Chest x-rays show no free air for 12-24 hours

Comfort measures and pain relief should be provided to the infant during removal of the chest tube.

The chest tube is removed rapidly, and a sterile petrolatum gauze pressure dressing is applied.

Outcomes are dependent upon the severity of the underlying pulmonary pathophysiology.

• Mortality is high in infants who experience - o Pneumopericardium o Bilateral pneumothoraces o Bilateral pulmonary interstitial emphysema (PIE)

For those who survive bilateral PIE, there is a high risk of chronic lung disease.

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