Please confirm that you would like to log out of Medscape.
If you log out, you will be required to enter your username and password the next time you visit.
Log outCancel
When Distress Is Failure: Pediatric Respiratory Illness
Image of an infant with severe respiratory syncytial virus (RSV)-related pneumonia from Humphreys G. Bull World Health Organ. 2015;93(5):290-1. [Open access.] PMID: 26229198; PMCID: PMC4431520.
When Distress Is Failure: Pediatric Respiratory Illness
Understanding the progression of respiratory distress and respiratory failure in children is crucial, especially during the major viral pulmonary season for this population: winter.[1] The differential diagnosis for pediatric respiratory illness is broad and wide-ranging.
One of the most common causes of pediatric respiratory failure is viral bronchiolitis.[1,2] It is the predominant cause of inpatient admissions among children in their first 2 years of life. RSV alone results in an annual 57,000 hospitalizations of those younger than 5 years in the United States, with an estimated 200,000 deaths yearly.[3] Moreover, viral coinfections or bacterial superimposed pneumonias may occur in over 30% of cases, causing worsening pulmonary status in which respiratory distress can quickly progress into respiratory failure.[1,2,4]
Radiograph of a child with RSV showing bilateral perihilar fullness from Wikimedia Commons | James Heilman, MD.
When Distress Is Failure: Pediatric Respiratory Illness
Higher Risk of Respiratory Failure in Children Than Adults
Children are at greater risk of respiratory failure than adults due to anatomic differences, a decreased ability to compensate, and functional differences in respiration.[5,6] Anatomic differences in pulmonary size and function mean the pediatric airways are smaller and more prone to obstruction. In addition, the smaller upper airways create an increased resistance to airflow. The lower airways have a greater tendency to collapse or are more prone to atelectasis, thereby requiring greater inspiratory pressures to remain open.
Infant ventilation is dependent on the diaphragm and respiratory rate; thus, in the setting of respiratory distress, muscular effort and oxygen consumption increases.[5,6] Hypoxemia can develop quickly—This is the most common cause of cardiovascular collapse in children.
The pediatric airway continuously changes until about age 8 years when it becomes anatomically similar to that of an adult airway. The differences and their clinical significance are outlined below[5]:
Newborns are primarily obligate nose breathers, thus they are more prone to distress from nasal obstruction (ie, mucus). Infants transition to nose and mouth breathers as they grow.
The cricoid is the narrowest portion of the pediatric airway (vs the laryngeal inlet in adults), causing a funicular shape with a more anteriorly positioned larynx and resulting in more susceptibility to airflow compromise from even a small amount of inflammation and secretions.
The trachea in children is narrower and has softer cartilage, with a higher risk of inspiratory collapse in the setting of partial obstruction.
The pediatric epiglottis is longer, softer, and omega in shape, all of which can contribute to laryngomalacia and obstruction.
The tongue in children is larger relative to their jaw, which can cause obstruction, especially during periods of decreased tone such as when sleeping, under sedation, and with central nervous system dysfunction.
Image from Wikimedia Commons | Sunshineconnelly.
When Distress Is Failure: Pediatric Respiratory Illness
To understand anatomic differences in the pediatric lower airway and their significance, it is important to be familiar with the mechanics of inspiration and expiration.
Inspiration is an active maneuver that involves contraction and downward movement of the diaphragm while the rib cage expands and the rib muscles contract (left image).[5] These actions allow for an increase in air volume in the chest.
In contrast, exhalation is a passive movement that allows the diaphragm to relax and move back up into the rib cage while the rib muscles also relax (right image), thus reducing air volume in the chest.[5]
Images of mean thoracic morphology across age groups from Bastir M, Garcia Martínez D, Recheis W, et al. PLoS One. 2013;8(9):e75128. [Open access.] PMID: 24073239; PMCID: PMC3779208.
When Distress Is Failure: Pediatric Respiratory Illness
Many lower airway anatomic differences exist in the pediatric population relative to adults. These may provide challenges when children are in respiratory distress, including the following[5,6]:
The ribs in children are in a more horizontal position, which limits the ability of the thorax to expand on inspiration. Thus, most of their inspiratory mechanics is dependent on diaphragmatic contraction.
Infants have a flatter diaphragm, which produces even less efficient movement.
Children have an increased susceptibility for smaller airway collapse due to their (1) having weaker intercostal muscles as well as a more compliant and cartilaginous chest wall, which causes elastic recoil during expiration, and (2) having not only just 10% of the amount of alveoli of adults but also smaller alveoli.
Image courtesy of Fatima Westry, MS, PA-C.
When Distress Is Failure: Pediatric Respiratory Illness
Another important anatomic factor in the pediatric lower airway is a smaller diameter and the effect of edema on the airway, as described by Poiseulle's law.[5] Poiseulle's law states that resistance in the airway is inversely proportional to the radius of that airway to the fourth power.
Consequently, small changes in airway diameter can cause large changes in resistance to airflow through that diameter.[5] In the image shown, the presence of 1 mm of edema in an infant airway reduces the airway radius by haIf while raising the resistance by 16-fold, whereas in adults, the resistance only increases by 3-fold.
This principle explains why when the airways of newborns and infants—whose tracheas are about one third the size of an adult's—are subjected to edema, inflammation, or physical obstruction (ie, secretions), these patients can suffer respiratory distress or respiratory failure more easily than adults.
Image of intercostal retractions in a newborn with respiratory distress from Wikimedia Commons | Bobjgalindo.
When Distress Is Failure: Pediatric Respiratory Illness
Respiratory distress is defined as an increase in respiratory rate and effort, which may involve the following features[5,6]:
Increased breathing rate per minute (tachypnea)
Nasal flaring
Abnormal, noisy, or labored breathing
Retractions (shown): Increased respiratory muscle effort results in a collapse of soft tissue that can be seen in various areas on an infant's chest (below or between the ribs, sunken neck).
Elevated heart rate (tachycardia)
Pale or blue skin (cyanosis)
Change in body position: Patients lean forward or tilt up their head.
Specific breath sounds may be associated with upper versus lower airway distress.[5,6] In upper airway respiratory distress, stridor—an abnormal high-pitched, wheezing inspiratory sound that indicates disruptive airflow in the larynx —may be appreciated. In lower airway respiratory distress, wheezing, which has also been described as musical sounds mainly during expiration, may be more prominent.
Source of table content: Pierre L, Pringle, EJ, eds. Pediatric Fundamental Critical Care Support. Third ed. Mount Prospect, Ill: Society of Critical Care Medicine; 2018.[6] Right image from Wikimedia Commons | James Heilman, MD.
When Distress Is Failure: Pediatric Respiratory Illness
Many causes of upper airway diseases may lead to respiratory distress, often categorized as anatomic disorders, infections, external or internal compression, and other miscellaneous diagnoses (shown).[6]
Images from Ciet P, Tiddens HA, Wielopolski PA, et al. Pediatr Radiol. 2015;45(13):1901-15. [Open access.] PMID: 26342643; PMCID: PMC4666905.
When Distress Is Failure: Pediatric Respiratory Illness
Causes of lower airway disease are generally divided into lower airway obstruction and conditions that affect the lungs.[5]
Etiologies of lower airway obstruction include the following[5]:
Asthma
Foreign body aspiration
Bronchiolitis
Neoplasm/mass
Conditions that affect the lungs include the following[5]:
Pneumonia
Cystic fibrosis (shown): The image shows multiple areas of mosaic pattern that are probably areas of hypoperfusion (arrows) in a boy with cystic fibrosis.
Pulmonary edema
Pneumothorax
Pleural effusion
Interstitial lung disease
Chronic respiratory failure
Neuromuscular disease
Abdominal pathology or complications
Image from Wikimedia Commons | Momofbear.
When Distress Is Failure: Pediatric Respiratory Illness
Respiratory failure occurs when the pulmonary system does not provide adequate oxygenation, ventilation, or both to maintain the body's metabolic demands.[7-9] It can then progress to respiratory or cardiac arrest. Respiratory failure is the most common cause of cardiac arrest in children.
Acute pediatric respiratory failure can develop in minutes to hours, whereas chronic respiratory failure can progress over several days or longer.[7-9] Signs of respiratory failure in children include:
Grunting, head bobbing
Severe tachypnea and retractions
See-saw breathing
Bradypnea or apnea
Tachycardia or bradycardia
Cyanosis
Mottling, pallor
Decreased responsiveness
Absent air movement
Hypoxemia despite oxygen therapy
Patients with respiratory failure require prompt airway management and adjunctive supportive therapies (eg, supplemental oxygen) and noninvasive ventilatory support (eg, bilevel positive airway pressure [BiPAP]).[7-9] Severe respiratory failure and respiratory arrest require mechanical ventilation or extracorporeal membrane oxygenation (ECMO).
Chest x-ray of a 1 year old shows multiple subsegmental atelectasis and areas of air trapping from Eltahir S, Ahmad KS, Al-Balawi MM, et al. J Med Case Rep. 2016;10:97. [Open access.] PMID: 27091362; PMCID: PMC4836084.
When Distress Is Failure: Pediatric Respiratory Illness
In hypoxemic respiratory failure, the partial pressure of oxygen (PaO2) in the arterial blood falls below 60 mmHg, correlating with pulse oximetry saturations lower than 90%.[7,9] Pediatric cases are most often the result of a ventilation-perfusion (V/Q) mismatch and diffusion impairment.
In V/Q mismatch, an unequal relationship exists between capillary perfusion and alveolar ventilation, leading to impairment of oxygen transfer (atelectasis, pneumonia, bronchospasm, pulmonary hypertension, pulmonary embolism). When a diffusion defect occurs, oxygen and carbon dioxide (CO2) diffusion is limited by changes at the capillary-alveolar membrane (alveolar or interstitial inflammation or fibrosis). Other common etiologies of hypoxemia include the following[7-9]:
Alveolar hypoventilation: An increase in CO2 displaces alveolar oxygen.
Right-to-left shunt: Blood flows from the right side of the heart to the left side without being oxygenated (intracardiac shunts, pulmonary vascular malformations).
Low inspired fraction of oxygen (FiO2): Being at higher altitudes may reduce the inhaled oxygen concentration.
Oxygen administration generally resolves most causes of hypoxemia, except for shunts.
When Distress Is Failure: Pediatric Respiratory Illness
Polysomnography tracing of a 6 year old reveals multiple obstructive apnea events (green-shaded areas) associated with oxyhemoglobin desaturation (yellow-shaded areas) and electroencephalogram (EEG) arousals (red-shaded areas). Image courtesy of Medscape. ECG = electrocardiogram, EOG = electrooculogram, EMG = electromyogram; SaO2 = oxygen saturation.
Hypercapnic respiratory failure
Hypercapnia is an elevation in the partial pressure of CO2 (PaCO2) in arterial blood, indicating impairment in ventilation and often leading to hypercapnic respiratory failure.[7-10] Mechanisms include hypoventilation (more common), increased CO2 production (hypermetabolic states), and increased dead space (asthma), and etiologies include respiratory center failure, neuromuscular conditions, and chest wall abnormalities.[7-10] Signs may include respiratory distress, tachypnea, somnolence, poor respiratory effort, agitation, or changes in mental status.
Suspect hypercapnic respiratory failure particularly in patients with altered levels of consciousness, drug intoxication, brain or spinal cord injury, muscle weakness, or conditions such as restrictive lung disease and obstructive sleep apnea.[7-10]
Normal oxygenation with elevated end-tidal capnography may occur.[7-10] Blood gases reveal respiratory acidosis with a PaCO2 above 50 mmHg. In chronic hypercapnic respiratory failure, pH will be normal with an elevated PaCO2. Persistent, untreated hypercapnia leads to hypoxemia.[7-10]
Image showing peripheral cyanosis over an infant's palm from Suhail M, Faizul-Suhail M, Khan H, Suhail S. J Clin Med Res. 2009;1(4):240-3. [Open access.] PMID: 22461877; PMCID: PMC3299189.
When Distress Is Failure: Pediatric Respiratory Illness
Some medical conditions can complicate the recognition of respiratory distress and impending respiratory failure, or they may muddle the differential diagnosis and/or management strategies.[7,8] Being aware of and assessing for conditions such as the following can facilitate early and appropriate intervention[7,8]:
Neuromuscular or metabolic disorders: The typical signs of an increased respiratory effort (eg, retractions) may be absent due to muscle weakness. Patients can be at risk for complete airway obstruction from reduced muscle tone.
Impeding the movement of the diaphragm: Adequate respiration can be compromised, as seen with abdominal distention, lung hyperexpansion, or air trapping
Postictal states: The risk of hypoventilation exists, particularly after taking antiepileptic medications.
Inaccurate pulse-oximetry: Carbon monoxide poisoning, methemoglobinemia, or poor tissue perfusion from shock or hypothermia can result in flawed readings.
Diabetic ketoacidosis: Kussmaul breathing, a compensatory mechanism to increase CO2 elimination from the body in an effort to normalize blood pH, can mimic respiratory distress.
Image from Wikimedia Commons | Spiritia and Offnfopt.
When Distress Is Failure: Pediatric Respiratory Illness
Factors vital in the determination, management, and treatment of respiratory distress and respiratory failure are outlined below.[5]
Positions for optimal open airway: Place the patient sitting upright or in the sniffing position.
Maneuvers to open the airway: Suctioning can remove a mucosal obstruction, clearing the airway. Performing the head-tilt and jaw-lift maneuver can help to align the airway for optimal airflow and to move a tongue obstruction (shown).
Oxygenation and ventilation supplementation: Bag-mask or positive pressure ventilation, or oxygenation support with a nasal cannula, high-flow nasal cannula, simple face mask, or non-rebreather mask may be required.
Optimization of pharmacotherapy: Use of bronchodilators, steroids, antihistamines, and mucolytics is imperative.
Adjunctive management of circulation and normothermia: Treat fevers; hydration supports respiratory status.
Monitoring of respiratory status: Track oxygen saturation, capnography, and blood gases to aid in determining the respiratory status of the child, but do not discount the physical assessment.
E-cigarette or Vaping Product Use-Associated Lung Injury (EVALI): A Case Study
The popularity of e-cigarettes and vaping products has surged in the past decade. Although they have been marketed as safe alternatives to traditional cigarettes, more recent evidence reveals pulmonary toxicity and other effects from e-cigarette vapors.Medscape Reference Slideshow, Oct 2020
Commenting is limited to medical professionals. To comment please Log-in.
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Close
Contributor Information
Authors
Priscila Nakano, MSN, APRN, CPNP-AC
Baylor College of Medicine/Texas Children’s Hospital
Houston, TX
Disclosure: Priscila Nakano, MSN, APRN, CPNP-AC, has disclosed no relevant financial relationships.
Cynthia Nelson, MPH, MS, PA-C
Baylor College of Medicine/Texas Children’s Hospital
Houston, TX
Disclosure: Cynthia Nelson, MPH, MS, PA-C, has disclosed no relevant financial relationships.
Fatima Westry, MS, PA-C
Baylor College of Medicine/Texas Children’s Hospital
Houston, TX
Disclosure: Fatima Westry, MS, PA-C, has disclosed no relevant financial relationships.
Reviewer
Jaime Jump, DO
Baylor College of Medicine/Texas Children's Hospital
Houston, TX
Disclosure: Jaime Jump, DO, has disclosed no relevant financial relationships.
Editor
Olivia Wong, DO
Section Editor
Medscape Drugs & Diseases
New York, New York
Disclosure: Olivia Wong, DO, has disclosed no relevant financial relationships.
Close
References
Ralston SL, Lieberthal AS, Meissner HC, et al, for the American Academy of Pediatrics. Clinical practice guideline: the diagnosis, management, and prevention of bronchiolitis. Pediatrics. 2014 Nov;134(5):e1474-502. PMID: 25349312
Paluch L. Identifying and managing bronchiolitis. JAAPA. 2020 Sep;33(9):12-5. PMID: 32841971
Noor A, Krilov LR. Respiratory syncytial virus vaccine: where are we now and what comes next? Expert Opin Biol Ther. 2018 Dec;18(12):1247-56. PMID: 30426788.
Brealey JC, Sly PD, Young PR, Chappell KJ. Viral bacterial co-infection of the respiratory tract during early childhood. FEMS Microbiol Lett. 2015 May;362(10):fnv062. PMID: 25877546
Please do not use this form to submit personal or patient medical information or to report adverse drug events. You are encouraged to report adverse drug event information to the FDA.
Comments