Pediatric Pulmonary Emergencies

Your unit is called to respond for a five-year-old male with a recent history of fever, noisy breathing and drooling. The child’s mom states that the fever began this morning and has spiked this afternoon. The child’s parents were alarmed by his noisy breathing and called 9-1-1. Mom says the child has not taken anything by mouth since he became ill.

Your assessment reveals the child’s pulse to be 144; respirations 32, even and shallow; BP is 100/66; and his pulse oximetry reading is 90% on room air. He appears to be alert, awake and in acute respiratory distress. He seems to prefer an upright or forward-leaning position. His skin is hot and moist without a rash; the oropharynx is clear and the mucosa is moist; lung sounds are clear bilaterally, and the child has inspiratory stridor.

As you read this article, try to identify the disease process that is most likely causing this child’s symptoms and develop a prehospital management process for this child. This case will be revisited, and the diagnosis and treatment discussed at the end of this article.

The common denominator for unexpected deaths in children is hypoxia. This encompasses a diverse group of illnesses and conditions, including infectious diseases, choking, drowning, heart disease and pulmonary compromise. Children maintain cardiovascular function until they become extremely hypoxic. The child’s rapid metabolism requires oxygen, and the body’s source for oxygen comes from the pulmonary system. Children with pulmonary problems can ultimately progress to cardiovascular compromise, and eventually to death.

Airway Anatomy and Physiology

Children have different anatomic and physiologic qualities from adults. The tongue is one of the most obvious anatomical differences between the adult and child. The pediatric tongue is larger than the adult’s in relation to the amount of free space in the oropharynx. The large tongue creates a significant probability for airway occlusion and leaves little room for airway swelling. The size of the tongue is one explanation for why children are obligate nose-breathers; breathing through the nose is easier because it provides a direct path for airflow without concern for any obstruction that the tongue may cause.

The pediatric trachea is much more pliable than the adult’s. Children do not have completed tracheal rings (with the exception of the first tracheal ring). The increased pliability of the trachea can be troublesome in the pediatric patient because hyperextension and/or hyperflexion of the neck may lead to complete or partial airway occlusion.

The small diameter of the trachea allows a small amount of swelling to cause significant compromise of airflow. This is the anatomic reason why children develop a croupy cough and adults do not.

The pediatric epiglottis tends to be very large and is more U-shaped or oblong, making it more difficult to control when attempting intubation. There are a variety of practices related to pediatric intubation using a straight (Miller) blade versus a curved (MacIntosh) blade. The reason for this preference is attributed to the unique shape of the epiglottis. The curved blade fits into the vallecula and indirectly lifts the epiglottis out of the way, while the straight blade gets under the epiglottis and directly elevates it for visualization of the vocal cords. The long epiglottis can flop down around the curved blade and may cause visual obstruction of the airway.

The adult larynx sits at about the level of the fourth or fifth cervical vertebra; the pediatric larynx sits at about the level of the first or second cervical vertebra. If the pediatric larynx were lower, as the child swallowed food, it would go directly into the trachea. This is important to realize because the higher the larynx is, the more anterior the airway is. To be successful in managing a child’s airway, it should always be assumed that the airway is very anterior.

The mainstem bronchi in young children have less of an angle than in adults. As a result, aspiration can occur in either the left or right mainstem bronchus. As children grow, the chest diameter increases and the angle of the left bronchus increases as well.

Chest Anatomy and Physiology

The anatomy of the pediatric chest results in differences in how respiratory compromise is observed. The bones in young children are not completely calcified and tend to be flexible. When a child suffers some form of respiratory compromise, he or she will attempt to increase the volume of air entering the chest through the utilization of accessory muscles. Children’s ribs are more horizontal than rounded like adults’. The horizontal nature of the ribs provides very little leverage to increase the anterior and posterior diameters of the chest. This does not provide the degree of lift that is necessary to increase the volume of air within the chest when it is needed most. Some children have less-developed accessory muscles, which makes it more difficult to increase the strength and depth of ventilations. The lack of accessory muscles is the reason many children in distress will be observed using diaphragmatic breathing.

The child’s sternum is very pliable. When the accessory muscles are being stretched, they pull on various bony structures, including the sternum.

The relationship between heart size and thoracic cavity size helps to explain why children have less pulmonary reserve than adults. Children have less ability to increase volume within the lungs because the lungs are only capable of expanding to the degree there is space to expand; the heart occupies much of the thoracic cavity.

The pediatric abdominal cavity is very small and has very large organs compressed within it. A significant problem with the overcrowding that occurs in the abdomen is that it has a negative effect on the compensatory mechanisms of respiration. Children rely heavily on rate of respiration for compensation because they are unable to increase respiration depth, due to the diaphragm’s inability to move downward against the abdomen. Conversely, adults can increase both rate and depth of respiration when they experience respiratory difficulty.

Respiratory Distress, Failure and Arrest

EMS providers need to be precise in their use of the terms respiratory distress, respiratory failure and respiratory arrest. The distinction dictates how aggressive providers need to be in managing their patient.

Respiratory distress is defined as an abnormal physiologic condition identified by increased work of breathing; respiratory failure is defined as the period when the child exhausts his energy reserves, can no longer maintain oxygenation and ventilation, and begins to decompensate; and respiratory arrest is defined as the absence of effective breathing.

It is important to note that although the cause of the respiratory problem may not be evident to the EMS provider in most pediatric interactions, aggressive prehospital management must still take place to prevent a bad outcome for the patient. The EMS provider needs to help determine potential causes of the hemodynamic and/or respiratory compromise, but identifying the exact cause of the pathology is extremely difficult to accomplish in the field and is not necessary to provide lifesaving treatment. The goal is to identify a set of likely causes and treat the patient based on those likely causes.

Respiratory distress indicates that the patient still has the ability to compensate for himself. Respiratory failure is present when the patient has exhausted all of his compensatory mechanisms. A patient in respiratory distress can progress to respiratory failure, and a patient in respiratory failure can progress to respiratory arrest if management is not rapid and aggressive.

Assessing the Short-of-Breath Child

When assessing a child with respiratory compromise, it is important not to upset the child and exacerbate the pulmonary event. The general approach includes a careful history, a focused examination, use of available monitors (based on local protocols and level of certification) and discussion with online medical control.

Causes of respiratory compromise may include mechanical obstruction of the airway by a foreign body, edema, a mucus plug or bronchospasm. Other causes that do not directly affect the airway but can have untoward effects include congenital heart defects and trauma or infection resulting in chest wall compromise.

Differential Diagnosis of Respiratory Compromise

Differential diagnosis is exactly what the term suggests: using differences in a patient’s presentation to diagnose a medical problem. A differential diagnosis is implemented by listing clinical conditions and comparing them against other clinical conditions to produce a specific diagnosis or probability of a specific diagnosis. A differential diagnostic approach will be used for the disease processes discussed in this article.

Bronchospasm

Bronchospasm is defined as abnormal narrowing of the lumen of the bronchi due to spasm of the bronchial smooth muscle. In a number of clinical situations, there will be no specific disease diagnosed. Pediatric patients may not be assigned diagnoses because their respiratory emergency is the result of a hypersensitivity reaction to some substance. Unlike adults, a young patient who experiences a bronchospastic event will be treated for the wheezing. Adults are often diagnosed with a specific disease process that results in bronchospasm (asthma, COPD, congestive heart failure), which makes treatment very specific. Until children have a recurrence of bronchospasm, they will be diagnosed with reactive airway disease—a nonspecific, catch-all diagnosis used when a specific diagnosis is unknown.

Asthma

In the year 2000, there were 14 million people with asthma, of whom 4.8 million were under age 18. Asthma in children accounts for a loss of 10 million school days and costs parents or the child’s primary caregivers an estimated $726.1 million in lost work days. A more disturbing statistic is that from 1983 to 1996, the adverse outcomes and deaths related to asthma tripled.

Asthma is a long-term inflammatory process that targets the lower airways and is manifested through increased mucus production and an acute narrowing of the airways through inflammation of airway tissue, leading to swelling within the airways.

The narrowing of the airway diameter increases airway resistance through the bronchioles. As the bronchiole smooth muscle contracts and the airways are narrowed, air moves forcefully through the tiny passages, producing the wheezing that is heard through the stethoscope.

From an anatomical perspective, it is important to remember that each bronchial airway is wrapped with smooth muscle capable of contraction and relaxation. These tiny muscles respond to local triggers and to a variety of substances that can be inhaled. This is important because it explains the mechanics of bronchiole spasm (shortened to bronchospasm) and the therapy used to treat wheezing.

The underlying problem with asthma is an increased responsiveness of bronchial smooth muscles, leading to bronchoconstriction. When bronchiole airways spasm, airway resistance increases, the expiratory phase of respiration increases and prolongs, and expiratory volumes decrease. In other words, a large amount of air may be taken into and held in the lungs but, because of the narrow passages, it cannot escape. An increase in airway resistance causes air to be trapped in the terminal airways, leading to carbon dioxide retention. Asthma attacks are usually associated with widespread airflow obstruction. This obstruction of the airways is often reversible when treatment is aggressive and initiated early.

Common symptoms of asthma include shortness of breath, chest tightness, wheezing and coughing.

Treatment of asthma is focused on reversing bronchospasm, correcting hypoxia and treating airway inflammation. Asthma is a disease of ventilation, so asthma patients will not become hypoxic until ventilation has been severely compromised. But many patients describe symptomatic improvement with supplemental oxygen, so an initial treatment step is to administer oxygen. Most patients will benefit from oxygen administered by cannula, but if the pulse oximeter reading is below 92%, the patient is likely to be in significant trouble, and oxygen should be administered by 100% nonrebreather mask. Oxygen will work to correct hypoxia but will not reverse bronchospasm or inflammation. To alleviate these symptoms, inhaled beta-agonists should be used under local protocol. Beta-agonists are drugs that stimulate beta receptors in the small muscles within the bronchioles, resulting in bronchodilation. Ventolin, Proventil and Atrovent are a few examples of inhaled beta-agonists. Epinephrine and terbutaline are non-specific alpha- and beta-agonists, and some systems will have paramedic-level personnel administer these medications by subcutaneous injection, particularly for patients in severe distress at presentation. This subcutaneous treatment may allow some initial bronchodilation, particularly in the pediatric patient, and therefore make inhalation treatments with beta-agonists even more effective.

Corticosteroids may also be used to help decrease inflammation within the airways after the acute bronchospasm has been relieved. It is important to realize, however, that steroids take several hours to begin working and should not be viewed as an emergent airway treatment modality.

If bronchospasm is not effectively relieved by pharmacological means, intubation may be necessary. For the child in severe respiratory distress, it is imperative that the EMS provider be aggressive with therapy to prevent having to intubate the patient. Positive pressure ventilation may actually worsen the condition of an asthmatic patient because of increased pulmonic pressures and the potential for barotrauma or increased air trapping.

Bronchiolitis

Bronchiolitis is an acute infectious process of the lower respiratory tract in young children. Bronchiolitis typically occurs in children ages 2–24 months and is most commonly caused by a virus. To EMS providers, the most well-known infectious form of bronchiolitis is respiratory syncytial virus (RSV). Symptoms of bronchiolitis include fever, tachycardia and/or tachypnea, shortness of breath, chest tightness, wheezing and coughing.

The bronchiolitis patient will experience increased mucus production, acute narrowing of the airways through inflamed airway tissue and clogging of the airway with infectious byproducts.

Bronchiolitis patients typically present in the same way as asthma patients, with a few variations. The bronchiolitis patient will wheeze due to narrowing of the airway diameter. The major difference is that the bronchiolitis patient will likely have a fever and a relatively slow onset of symptoms. It is not necessary to differentiate asthma from bronchiolitis in the acute patient because the pathology is the same and will not affect your treatment decisions.

Treatment of bronchiolitis is focused on correcting hypoxia, reversing bronchospasm, treating airway inflammation and, if possible, identifying and treating the causative pathogen. The first step is to administer high-flow oxygen by mask. Oxygen works to correct the hypoxia, but will not correct bronchospasm or inflammation. To alleviate these symptoms, use inhaled beta-agonists.

The decision to assist ventilations to prevent respiratory failure is pivotal to the overall outcome of the child. The conservative approach to invasive airway management is preferred.

Airway Obstruction

Airway obstruction is a true medical emergency. Identifying and clearing an airway obstruction takes precedence over any other treatment. It is important to remember that a patient with a complete airway obstruction will be unable to breathe, talk or cough.

The first phase of managing a foreign body airway obstruction is implementation of basic airway maneuvers such as back blows and chest thrusts in infants and the Heimlich maneuver in older children. Do not delay transport of this patient. Interventions should be performed while en route to the ED. If the foreign body is expelled from the airway at any time, the EMS provider should, if visible, remove the object from the victim’s mouth. It is imperative not to perform a blind finger sweep on the pediatric airway; inserting a finger into the posterior pharynx may lodge the object further into the airway. If basic maneuvers do not work to dislodge the obstruction, there are several ALS interventions that may be employed.

ALS interventions that may be successful in the pediatric patient with an obstructed airway include direct laryngoscopy to visualize the obstruction, and, if visible, removal of the obstruction with Magill forceps.

Laryngoscopy may move the object enough to allow partial ventilation. If not, the airway obstruction must be bypassed. This is the rare circumstance where an ALS provider may need to consider needle cricothyroidotomy, which will allow for oxygenation but will not allow for the exchange of gasses.

In some circumstances, introducing positive pressure through the trachea will eject the foreign object from the upper airway. If this does not occur, using rapid and low-volume ventilation (jet ventilation) will allow both oxygenation and ventilation to occur despite the foreign body occlusion. Medical protocols will direct EMTs in this rare circumstance, or immediate contact should be made with online medical control.

Epiglottitis

Epiglottitis is an acute, severe, life-threatening disease of the upper airway. In epiglottitis, a local infection of the epiglottis occurs, followed by bacteremia. The epiglottis and the structures connected to or immediately surrounding it become inflamed and edematous, leading to a compromised airway at the level of the epiglottis and respiratory compromise.

Epiglottitis has been predominantly referred to as a disease of children ages 2–7, but that is no longer necessarily true. There has been vast progress in reducing epiglottitis since the mid 1980s; this is primarily attributed to introduction of the Hib (Haemophilus influenzae type B) vaccine. As a result of the Hib vaccine, epiglottitis is being seen more in young adults than in children.

The typical presentation for epiglottitis is a rapid onset of fever that may or may not be accompanied by a sore throat. The child will likely refuse to eat or drink due to the irritation, but will eventually be unable to tolerate his own secretions and will begin to drool. He may develop signs of upper airway obstruction, with inspiratory stridor and some degree of respiratory compromise. The older child will sit with his neck extended in the sniffing position. This position is maintained to assist him in optimizing the amount of open airway. This child will typically avoid coughing, as this further irritates the inflamed tissue.

Treatment of epiglottitis is focused on preventing airway obstruction. The first treatment step is to administer high-flow oxygen through a blow-by mask, as tolerated by the child. The goal of all EMS?providers should be to ensure that the child remains calm. There is absolutely no need to do a forced inspection of the child’s airway, and it should not be attempted. Attempting oral intubation in a child with suspected epiglottitis is contraindicated in the field.

If the child deteriorates and requires assisted ventilation in the prehospital setting, use a slow ventilation sequence by bag-valve-mask. If this is not effective, advanced providers would then need to perform a needle cricothyroidotomy.

Croup

Croup is a viral infection of the upper respiratory tract that may, very rarely, cause airway obstruction. Croup is most frequently found in children with a recent history of upper respiratory infection and symptoms. As mentioned in the anatomical review section of this article, the narrowest portion of the pediatric airway is directly beyond the glottic opening, or just below the level of the vocal cords. This is an important point, because the narrow airways are directly affected by edema and fluid accumulation secondary to croup.

The typical presentation of croup includes the hallmark barking cough, accompanied by stridor and a low-grade fever. Children are commonly sick for 1–5 days before the onset of croup. The diagnosis of croup is made by observing physical findings, coupled with a significant history of illness.

The typical presentation for epiglottitis is a rapid onset of fever, sore throat and unwillingness to eat or drink. In contrast, the child with croup will have no difficulty eating or drinking because the point of irritation is below the level of the glottis, and neither food nor fluid will cause direct irritation of the subglottic tissues.

Treatment of croup is aimed at preventing airway obstruction. The first treatment is to administer oxygen and moisture—ideally, humidified oxygen—as tolerated by the child. Your goal should be to ensure that the child remains calm. Differentiating between epiglottitis and croup may be difficult for EMS providers. It is not recommended to attempt an inspection of the child’s airway.

If the child is acutely ill and humidified oxygen is not successful in reducing airway edema, initiate immediate transport to the closest pediatric emergency care center. Management of croup in an emergency care center includes administration of racemic epinephrine, a form of aerosolized epinephrine that stimulates vasoconstriction. The idea is that aerosolized epinephrine can shrink the airway tissues by vessel constriction in the edematous tissue. The problem with racemic epinephrine, and the reason it is not given in the prehospital setting, is that it may contribute to rebound swelling of the airways once the epinephrine has worn off. The risk for rebound swelling makes the use of steroids critically important in the croup patient who has received racemic epinephrine. This child may spend several hours in the hospital for observation to ensure that rebound edema does not present and he is able to adequately maintain his airway.

In the worst-case scenario, children may not respond to racemic epinephrine and will need endotracheal intubation. Intubating these children should be avoided in the prehospital setting until all other options have been exhausted.

Case Study Revisited

To review the opening scenario, you responded for a five-year-old male with noisy breathing, a fever and drooling. His vital signs were: pulse 144, irregular and strong; respirations 32 and shallow; BP 100/66; and pulse oximeter reading 90% on room air. This child has epiglottitis! He has drooling, inspiratory stridor, a rapid onset of fever, is in the tripod position and is oxygenating poorly.

There is an unfortunate conclusion to this real-life scenario.

The EMS providers believed this child was in acute respiratory distress and attempted to bag-mask ventilate him. When the mask was put on the child, he became agitated and hypoxic, then began to gasp for air and lost consciousness. After being laid flat, he went into respiratory arrest. On laryngoscopy, the paramedic said he was unable to visualize the airway structures. While en route to the ED, the paramedic attempted to intubate the child several times without success. The child quickly went into cardiac arrest, remained apneic and was pronounced dead 30 minutes after arrival in the ED.

Pulmonary emergencies are common in children and require expert prehospital care. Hypoxia kills children, and does so quickly. Identifying and treating life-threatening pulmonary illnesses can prevent death.

Bibliography

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The author would like to thank James A. Augustine, MD, for his review and contributions to this article.