Pulmonary Disorders



Pulmonary Disorders





Apnea

Katie Ward



Types



  • Central.



    • Disruption of afferent (cessation of output) or efferent (inability of peripheral nerves or respiratory muscles to receive input) signals of the central respiratory center.


    • Inappropriate response to hypercapnia and hypoxemia.


  • Obstructive.



    • Reduced airway patency secondary to some form of obstruction causing poor or no air movement through passage.


    • Usually results in significant respiratory effort that is ineffective.


Etiology



  • Central: immaturity of the respiratory center (premature infants), head trauma, toxin-mediated.


  • Obstructive: obstructive sleep apnea (OSA), mucopolysaccharidosis, craniofacial anomalies, obesity, adenoid or tonsillar hypertrophy, aspirated foreign body, vocal cord paralysis.


  • Mixed: obstructive and central.



Clinical Presentation



  • At time of evaluation, patient may appear clinically well.


  • History may include poor sleep patterns, fatigue, daytime sleepiness, or difficulty concentrating.


  • Examination during apneic episode: no respiratory effort, breath sounds, or chest wall movement; potential hypoxia, cyanosis, and bradycardia.


Diagnostic Evaluation



  • Polysomnography


  • Echocardiography and/or electrocardiography (EKG) to evaluate for cardiac sequelae.


Management



  • If adenotonsillar hypertrophy, referral to an otolaryngologist for possible adenotonsillectomy


  • If obese, weight management, including nutrition, exercise, and behavioral elements.


  • Noninvasive positive pressure ventilation (NIPPV): continuous positive airway pressure (CPAP) or bilevel positive airway pressure (BiPAP).



Acute Respiratory Distress Syndrome

Katie Ward


Background



  • Result of lung injury, specifically to the alveolar capillary barrier (alveolar epithelium, capillary endothelium), which is vital in maintaining lung fluid balance.


Diagnostic Criteria



  • Acute onset.


  • Bilateral infiltrates on chest radiograph (see Figure 3.1).







    FIGURE 3.1 • ARDS Radiographic Images. Nonuniform parenchymal involvement in ARDS. Anterior-posterior chest X-ray and CT scans corresponding to lung apex, hilum, and base from a patient with sepsis and ARDS. Images are taken with the patient in supine position, at a PEEP of 5 cm H2O. The CT scans illustrate the influence of the gravitational axis on the pattern of alveolar consolidation in ARDS: Nondependent regions are aerated, while dependent regions remain consolidated.


  • Pao2/Fio2 ratio of <200.


  • Noncardiogenic origin: pulmonary artery wedge pressure <18 mmHg or absence of clinical evidence of left atrial hypertension.


Etiology



  • Direct lung injury as a result of pneumonia, aspiration, pulmonary contusion, pulmonary embolism, submersion injury, or inhalational injury.


  • Indirect lung injury as a result of sepsis, shock, burn injury, pancreatitis, exposure to cardiopulmonary bypass, transfusionrelated acute lung injury (TRALI), or cardiopulmonary arrest.



Clinical Presentation



  • Tachypnea, labored breathing.


  • Hypoxia, labored breathing.


  • Hypocarbia followed by hypercarbia.


  • Rales/crackles, decreased breath sounds.


Diagnostic Evaluation



  • Chest radiography: bilateral infiltrates.


  • Arterial blood gas (ABG): Pao2/Fio2 ratio <200.


  • Complete blood count (CBC): evaluation for infectious process as well as hemoglobin level to calculate arterial oxygen content.


  • ECHO: evaluation for cardiogenic etiology of pulmonary disease.


  • Bronchoalveolar lavage (BAL): neutrophil activation, culture for infectious origin.


  • Oxygen index calculation ([Fio2 × MAP]/Pao2): If >20, consider high-frequency oscillatory ventilation (HFOV); if >40, consider extracorporeal membrane oxygenation (ECMO).


Management



  • Supplemental O2


  • Noninvasive ventilation (CPAP, BiPAP): may reduce intubation; Recent studies have included high flow nasal cannula (HFNC) as an additional modality to provide oxygenation prior to intubation or for management.


  • Intubation and ventilation.



  • High positive end-expiratory pressure (PEEP) to achieve Fio2 <0.5-0.6, low tidal volume (7-8 mL/kg); avoid peak inspiratory pressure (PIP)>30 cm H2O.


  • Permissive hypercapnia (unless contraindicated).


  • Escalation of symptoms.



    • Titrate PEEP upward.


  • HFOV.



    • Smaller tidal volume.


    • Higher mean airway pressures.


    • Limited PIPs.

Additional management strategies may include the following:



  • Surfactant.



    • Reduces alveolar surface tension.


    • Dosing: 50 to 100 mg/kg administered 1 to 2 times within 12 to 48 hours of initiation of mechanical ventilation.


  • Nitric oxide.



    • Results in capillary and pulmonary dilation.


    • Dose: 20-80 ppm continuous inhalation.


    • Requires methemoglobin level monitoring.


  • Conservative fluid management.


  • Neuromuscular blockade.


  • Bronchoscopy.


  • Corticosteroid administration.



    • No evidence in pediatrics.


    • Typically initiated 7 to 10 days into course of ARDS.


  • If oxygen index is not improving on conventional ventilator or HFOV, consider ECMO.



Air Leak Syndromes

Katie Ward



Etiology



  • Spontaneous.


  • Trauma.


  • Underlying lung disease.


  • Ventilator-induced.



Clinical Presentation



  • Depends on the location of air.


  • Pneumothorax.



    • Chest pain, dyspnea, tachycardia.


    • Ipsilateral hyperresonance to percussion, decreased air entry, decreased vocal fremitus.


    • Hypoxia: increased PIP on mechanical ventilation.


    • Tension pneumothorax: tracheal deviation (contralateral), hypotension, tachycardia, cyanosis—medical emergency.


  • Pneumomediastinum.



    • Chest pain, dyspnea, neck pain, subcutaneous emphysema, Hamman’s sign (i.e., crunching sound noted over the precordium space that is noted concurrent with heart tones rather than respirations; represents the sound of the heart beating against an air-filled space).


  • Pneumopericardium.



    • Tachycardia, tachypnea, mill wheel murmur, muffled heart sounds, hypotension.


Diagnostic Evaluation



  • Chest radiography.



    • Pneumothorax: thin line where lung is separated from chest wall.


    • Tension pneumothorax: shift of the mediastinum to the contralateral side (see Figure 3.2).






      FIGURE 3.2 • Tension Pneumothorax Chest Radiograph. Left tension pneumothorax produces collapse of the left lung and mediastinal shift to the right.







      FIGURE 3.3 • Pneumomediastinum Chest Radiograph. Asthmatic child with pneumomediastinum with air surrounding the small triangular thymus gland, extending as linear sheaths into the neck and superior mediastinum (upper arrows) and extending along the lower left cardiac edge (lower arrows).


    • Pneumomediastinum: radiolucent streaks in mediastinum (see Figure 3.3).


    • Pneumopericardium: air in pericardial sac and “halo” sign (see Figure 3.4).


  • EKG.



    • Pneumopericardium: ST-segment elevations and low voltage.


Management



  • Depends on clinical symptomatology and patient’s clinical status.


  • Goal is to remove pathologic air and restore normal pressure gradient.


  • Needle decompression.



    • May require thoracostomy tube placement; most common in pneumothorax.


  • Limiting PIP, if requiring mechanical ventilation.


  • Surgical evacuation is rare.


  • Observation.







FIGURE 3.4 • Pneumopericardium Chest Radiograph. In this chest X-ray, air can be seen within the pericardial sac surrounding the heart (pneumopericardium), and in the right hemithorax.


Pneumothorax

Anne Vasiliadis



Etiology



  • Spontaneous pneumothorax is very rare but more common in males.



Risk Factors



  • Tall, thin males aged 10 to 30 years.


  • Smoking.


  • Underlying lung disease or connective tissue disorder.



Clinical Presentation



  • History: typically no inciting event for spontaneous pneumothorax.


  • Patient may report symptoms occurring after a maneuver that increases intrathoracic pressure, including Valsalva maneuver or other type of straining.


  • Patients with traumatic pneumothorax will generally report a history of blunt injury such as a trauma or fall.




Clinical Findings



  • Hypoxia, which can be acute.


  • Tachycardia.


  • Increased PIP or decreased expired tidal volume on mechanical ventilator.


  • Tension pneumothorax.



    • May result in tracheal deviation, decreased cardiac output leading to hypotension, tachycardia, and hypoxemia.


    • Medical emergency requiring immediate intervention.


Diagnostic Evaluation



  • Diagnosis typically confirmed with a posterior-anterior chest radiograph.



    • A lateral decubitus film may be needed if suspicion is high, but PA film is normal.


  • CT may help identify underlying blebs/bullae or very small pneumothoraces not detected by radiography.


  • There are multiple equations for calculating size of pneumothorax in adults, but these methods are not accurate in the pediatric population.


  • Laboratory evaluation: ABG may reveal decreased Pao2.


Management



  • Treatment is determined by type and size of pneumothorax and the clinical condition of the patient.


  • Observation.



    • Stable patients may only require observation with pulse oximetry and cardiorespiratory monitoring.


    • During observation, patient should receive 100% oxygen delivered via face mask to “wash out” nitrogen from pleural space.


  • Needle aspiration: Air is aspirated via a temporary needle inserted at the second intercostal space at the midclavicular line.


  • Thoracostomy tube: Catheter is placed in the pleural space at fourth, fifth, or sixth intercostal space at the midaxillary line and connected to water seal or suction.


  • Surgical intervention: video-assisted thoracoscopic surgery (VATS) and/orpleurodesis.



Asthma

Megan Trahan



Etiology/Types



  • Triggers.



    • Extrinsic: allergic/immunologic factors.


    • Intrinsic: Infectious process, very common trigger for status asthmaticus.


    • Exercise-induced bronchospasm.


  • Severity classification.



    • Intermittent asthma.



      • Symptoms (difficulty breathing, wheezing, chest tightness, and coughing).



        • Occur fewer than 2 days per week.


        • Do not interfere with normal activities.


        • Nighttime symptoms occur fewer than 2 days per month.


    • Mild persistent asthma.




      • Symptoms occur more than 2 days a week, but do not occur every day; they interfere with daily activities.


      • Nighttime symptoms occur 3 to 4 times per month.


      • Lung function tests are normal when there are no symptoms.


      • Lung function tests are ≥80% of the expected value and may vary slightly (peak expiratory flow [PEF] varies 20%-30%) from morning to afternoon.


    • Moderate persistent asthma.



      • Symptoms occur daily and interfere with daily activities.


      • Inhaled short-acting asthma medication is used daily.


      • Nighttime symptoms occur more than 1 time per week, but do not happen daily.


      • Lung function tests are abnormal (e.g., ≥60% and <80% of the expected value); PEF varies more than 30% from morning to afternoon.


    • Severe persistent asthma.



      • Symptoms occur every day and severely limit daily physical activities.


      • Nighttime symptoms occur often, sometimes every night.


      • Lung function tests are abnormal (≤60% of expected value); PEF varies >30% from morning to afternoon.


    • Acute asthma exacerbation.



      • Mild symptoms: Tachypnea without accessory muscle use.



        • Heart rate is <100 beats per minute.


        • Pulsus paradoxus is not present.


        • Auscultation of chest reveals moderate wheezing, which is often end-expiratory.


        • Oxygen saturation in room air is >95%.


      • Moderate symptoms: Tachypnea and accessory muscles use are common.



        • Loud expiratory wheeze with suprasternal retractions present.


        • Pulsus paradoxus may be present (e.g., 10-20 mmHg).


        • Oxygen saturation in room air is 91% to 95%.


      • Severe symptoms.



        • Tachypnea; respiratory rate >30 breaths per minute, based on age and activity.


        • Accessory muscles use with suprasternal retractions common.


        • Heart rate >120 beats per minute.


        • Wheezing; biphasic (e.g., expiratory and inspiratory); usually loud.


        • Pulsus paradoxus, common (e.g., 20-40 mmHg). Oxygen saturation <91% in room air.








TABLE 3.1 Asthma Presentation by Severity













Mild


Moderate


Severe


Impending Respiratory Failure


Exertional dyspnea Slight tachypnea No retractions No increased work of breathing.


Dyspnea at rest, some difficulty with phonation, tachypnea, loud expiratory wheezing, retractions, accessory muscle use, mild tachycardia, pulsus paradoxus of 10-25 mmHg, PEF 40%-69%, Spo290%-95%.


Dyspnea at rest, tripod position, difficulty with phonation, agitation, tachypnea, inspiratory and expiratory wheezing, retractions and accessory muscle use, tachycardia, pulsus paradoxus of 20-40 mmHg, PEF <40%, Spo2 <90.


Drowsy or confused, paradoxical thoracoabdominal movement, “silent chest” with absence of wheezing, bradycardia, no pulsus paradoxus secondary to muscle fatigue.




Clinical Presentation



  • Common symptoms include wheezing, shortness of breath, chest or abdominal pain, and cough which is often at night.


  • Symptomatology is often related to trigger.



    • Viral trigger: fever, rhinorrhea, sick contact exposure.


    • IgE-mediated trigger: strong patient or family history of atopy/allergies (Table 3.1).


  • Other signs and symptoms.



    • Forced or prolonged expiratory phase.


    • Hypoxia related to ventilation/perfusion (V/Q) mismatch.


    • Pulsus paradoxus, especially when severe asthma exacerbation is combined with hypovolemia.


Diagnostic Evaluation



  • Laboratory



    • ABG (not required in mild/moderate exacerbations).



      • Hypoxemia and hypocarbia with early or mild asthma exacerbation (e.g., respiratory alkalosis).


      • Worsening air trapping results in an inability to clear carbon dioxide, leading to normal or elevated Paco2 (e.g., respiratory acidosis).


      • Serum lactate level; elevated.



    • Electrolyte panel.



      • Evaluates Degree of dehydration and acidosis.


      • Hypokalemia; intracellular shifts of potassium are associated with β-agonist therapy


      • Magnesium level; in anticipation of magnesium sulfate therapy.


    • Imaging: chest radiography.



      • Not required for all children with asthma.


      • Evaluates for suspected pneumonia, pneumothorax and other air leak syndromes, cardiomegaly pulmonary edema.


      • Common findings:



        • Hyperinflation with flattened diaphragms.


        • Peribronchial thickening.


        • Narrowed cardiac silhouette.


Acute Management



  • Initial interventions.



    • Supplemental oxygen—first priority.


    • IV fluids.



      • Increased insensible losses with tachypnea.


      • Avoid overhydration; risk for pulmonary edema.


    • β-agonists (e.g., albuterol, levalbuterol).



      • Sympathomimetic medication, result in bronchial smooth muscle relaxation.


      • Intermittent dosing with inhaled nebulization (usually three doses in the first hour) or metered-dose inhaler.


      • Continuous nebulization for refractory asthma exacerbation; typically 10 to 20 mg/hour.


    • Corticosteroids target underlying airway inflammation.



      • IV formulation recommended in severe exacerbations or with high doses of β-agonist; a 3- to 5-day course typically recommended.


      • Taper dosing is recommended for steroid therapy >5 days.


    • Anticholinergics (e.g., ipratropium bromide).



      • Promotes bronchodilation without affecting mucociliary clearance.


      • Used most frequently in the emergency department to prevent hospitalization; data limited on inpatient use.


  • Admission criteria.



    • Symptoms after observation for 60 minutes.


    • Oxygen requirement.


    • Short-acting β-agonist required more than every 2 to 3 hours.


    • Prior ICU admissions.


Adjunct Therapies



  • Magnesium sulfate is classified as bronchodilator which inhibits calcium-mediated smooth muscle contraction.



    • Usually given as a rapid bolus (over 30 minutes) or as a continuous infusion.


    • Most common adverse reaction is hypotension.


    • Cardiac dysrhythmias noted with very high magnesium levels (10-12 mg/dL).


  • Terbutaline and epinephrine are β-agonists delivered through intravenous or subcutaneous route.



    • Terbutaline.



      • Administered as a bolus with or without infusion.


      • Monitor EKG and cardiac enzymes for myocardial ischemia.


  • Methylxanthines (e.g., theophylline, aminophylline).



    • Promote bronchial smooth muscle relaxation by unknown mechanism.


    • Used for patients with status asthmaticus refractory to steroids and inhaled/IV β-agonists.


    • Narrow therapeutic window; monitor drug levels.



      • Therapeutic level 10 to 20 mcg/mL.


    • High side-effect profile (e.g., nausea, vomiting, abdominal discomfort, arrhythmias, seizures).


  • Antimicrobials.



    • Common coinfections include pneumonia or acute sinusitis.


    • Macrolides have anti-inflammatory properties, although studies do not recommend empiric macrolide use.


  • Helium-oxygen mixture (Heliox): inhaled (no definitive evidence that this works).



    • Helium: low-density gas that reduces airflow resistance and allows laminar flow.


    • Enhances inhaled β-agonist delivery.


    • Mixtures include 60/40 (i.e., 60% helium, 40% oxygen), 70/30, and 80/20.


    • Can also be entrained into ventilator or noninvasive ventilator circuits.



      • Lowers peak airway pressures, facilitates weaning, but limited use if severe hypoxemia.


  • Noninvasive mechanical ventilation: includes CPAP and BiPAP.



    • Used for hypoxemia or increased work of breathing.


    • Reduces work of breathing and dyspnea.


    • Limited by patient cooperation.


  • High-flow nasal cannula can be used as a noninvasive method of respiratory support.


  • Mechanical ventilation (used in cases refractory to other therapies).



    • Increased risk for barotrauma, air leak syndromes, nosocomial infection, pulmonary edema, circulatory dysfunction, steroid/muscle relaxant-associated myopathy, and death.


    • Anticipate hypotension with onset of positive pressure ventilation (PPV) related to dehydration combined with the effects of PPV on preload.


    • Allow permissive hypercapnia, long expiratory phase with slow ventilator rates.


  • ECMO or inhaled anesthesia may be considered in extreme cases.


Chronic Management



  • Controllers: stepwise therapy; based on National Heart, Lung, and Blood guidelines.


  • β-agonist: monitor usage; >2 canisters per month requires reevaluation.


  • Asthma Action Plan: details when to use medications, call providers, and seek emergency care. Provided to each patient on every encounter.


  • Identify and avoid triggers; consider allergy evaluation.




Bronchiolitis

Danielle Mashburn



Etiology



  • Risk factors for severe disease include:



    • Prematurity, infants <6 months of age, underlying cardio-pulmonary disease, and immunodeficiency.



Clinical Presentation



  • Upper respiratory tract symptoms (e.g., rhinorrhea, congestion, low-grade fever).






    FIGURE 3.5 • Bronchiolitis Chest Radiographs. Chest radiographs of 6-month-old infant with hMPV bronchiolitis, showing hyperinflation and diffuse perihilar infiltrates.


  • Lower respiratory tract symptoms (cough, tachypnea, dyspnea, decreased oral intake).


  • Physical examination findings: hypoxia, respiratory distress, diffuse crackles/rhonchi, expiratory wheeze, prolonged expiratory phase, irritability.


Diagnostic Evaluation



  • Majority of cases can be diagnosed based on history and physical examination.


  • Laboratory testing, if indicated (or if needed for isolation purposes).



    • Respiratory viral culture or polymerase chain reaction.


    • Blood gas analysis: moderate/severe cases.


  • Chest radiography.



    • Patchy atelectasis, peribronchial thickening, perihilar prominence, airspace disease, hyperinflation (see Figure 3.5).


Management



  • Supportive therapy is mainstay.



    • Oxygen supplementation, rehydration, secretion clearance.


    • Routine use of corticosteroids, racemic epinephrine, and bronchodilators is not recommended.


  • In severe cases, patient may require initiation of:



    • High-flow nasal cannula therapy, NIPPV or mechanical ventilation.


Chronic Lung Disease (Bronchopulmonary Dysplasia)

Danielle Mashburn



Risk Factors



  • Prematurity, intrauterine growth restriction, extremely low birth weight, family history of lung disease, ventilator-associated volutrauma or barotrauma, oxygen toxicity, increased pulmonary blood flow, infection.



Clinical Presentation



  • Premature infant born with severe respiratory distress syndrome.



    • Tachypnea, retractions, scattered rales, hypoxemia, periods of apnea, cyanosis, hypercarbia, increased anterior-posterior chest diameter.


  • Long-standing oxygen requirement (>28 days postnatally), chronic diuretic and bronchodilator dependence.


Diagnostic Evaluation



  • Chest radiography.



    • Initial findings: pulmonary edema, atelectasis, hyperinflation.






      FIGURE 3.6 • Bronchopulmonary Dysplasia Chest Radiograph. This 2-month-old child was treated with mechanical ventilation during the first days of life for hyaline membrane disease. The chest radiograph shows generalized overaeration and course modularity with multiple cyst-like areas throughout both lung fields.


    • Chronic findings: hyperexpansion (air trapping), areas of focal hyperlucency (cystic changes), linear stranding (fibrosis) (see Figure 3.6).


  • Blood gas analysis: evaluates the ability to oxygenate and ventilate.



    • Respiratory acidosis usually present.


  • ECHO: evaluates for congenital heart disease (CHD) as cause of respiratory distress.


  • Otolaryngology evaluation: to exclude anatomic airway abnormalities.


Management



  • Therapies to avoid preterm birth.


  • Supportive care.



    • Goal: Promote neonatal growth while supporting respiratory needs and minimizing further injury through:



      • Lung-protective ventilator strategies or use of NIPPV as able.


      • Maintaining functional residual capacity by using optimal PEEP levels.


      • Judicious use of diuretic and bronchodilators.


      • Use of antibiotics until pulmonary infection excluded.


      • Prevent gastroesophageal reflux disease.


      • Nutritional support: may require nasogastric or gastrostomy tube feedings.


  • Use of steroids remains controversial and is not currently recommended (Table 3.2).


Congenital Central Hypoventilation Syndrome

Danielle Mashburn



Etiology



  • Mutation of PHOX2B gene.



    • Gene is essential for embryologic development of the autonomic nervous system in the neural chest.


    • Majority of cases are a result of spontaneous gene mutation.


    • In a small percentage of cases, congenital central hypoventilation syndrome is inherited (autosomal dominant).



Clinical Presentation



  • Usually presents in the newborn period.



    • Apnea, respiratory arrest, hypopnea, cyanosis, tachycardia, diaphoresis, lethargy, hypercarbia, hypoxemia.


  • Patients who present outside of newborn period.



    • Learning disabilities, growth failure, cor pulmonale.


    • Develop worsening symptoms with sleep.


    • Do not show classic signs of respiratory distress (e.g., tachypnea, retractions).



      • Exhibit monotonous respiratory rate and work of breathing despite hypoxemia and hypercarbia.


Diagnostic Evaluation



  • Genetic testing for PHOX2B gene mutation.


  • Polysomnography.



    • Findings include hypoventilation, hypoxemia, decreased minute ventilation, and frequent arousal.


  • Studies to evaluate for underlying metabolic, pulmonary, cardiac, or brainstem disease.



    • ECHO, chest radiography, brain MRI, urine amino and organic acids.


Management



  • Normalization of ventilation.



    • Tracheostomy with mechanical ventilation.


    • Chronic NIPPV.


    • Diaphragmatic pacing.


  • Supplemental oxygen is not adequate because it does not address hypoventilation.


  • Need continuous pulse oximetry and end-tidal CO2 monitoring.


  • Early intervention may improve long-term neurodevelopmental outcome.


Congenital Diaphragmatic Hernia

Danielle Mashburn



Etiology



  • Failure of pleuroperitoneal folds to close at 6 to 8 weeks gestation.



Clinical Presentation



  • Signs of respiratory failure in immediate newborn period.



    • Hypercarbia, hypoxia.


  • Physical examination findings: retractions, tachypnea, grunting, cyanosis, absent breaths, increased chest diameter, sounds on ipsilateral side, heart sounds shifted to contralateral side, scaphoid abdomen, presence of bowel sounds in thorax.


Diagnostic Evaluation



  • Antenatal ultrasound.




    • Commonly occurs in infants with a history of polyhydramnios.


    • Often diagnosed prior to birth: allows for counseling and postnatal planning.


  • Chest radiography.



    • Fluid-filled loops of bowel seen in thoracic cavity.


    • Associated mediastinal shift (see Figure 3.7).


  • ECHO.



    • Allows ability to evaluate for cardiac dysfunction and measures systemic and pulmonary pressures.


  • Chromosomal evaluation as disorder is frequently associated with anomalies.


Management



  • Cardiorespiratory stabilization.



    • Immediate intubation, sedation, and stomach decompression.


    • Bag-mask ventilation should be avoided as this will introduce air into gastrointestinal tract, worsening lung compression.


    • Lung-protective strategies (when stable) and pulmonary hypertension management.


    • Consider ECMO if conventional ventilation fails.


  • Delayed surgical intervention to repair defect.



    • Can be considered after hemodynamic stabilization and resolution of pulmonary hypertension.


  • Ongoing pulmonary care.



    • Chronic lung disease is common source of morbidity for survivors of congenital diaphragmatic hernia (CDH).






FIGURE 3.7 • Diaphragmatic Hernia. A: Abdominal surface of the diaphragm and the derivation of the components during development. The pleuroperitoneal membranes, the septum transversum, and the esophageal mesentery form the diaphragm. A Bochdalek hernia forms when there is a posterolateral defect. Morgagni hernias are less common and are present anteriorly. B: Chest radiograph of a child with a congenital posterolateral (Bochdalek) diaphragmatic hernia on the left. The mediastinum is displaced to the right by the intestinal loops present in the left chest.


Laryngotracheobronchitis/Croup

Andrea M. Kline-Tilford



Etiology/Types



  • Most commonly caused by parainfluenza types 1 and 2.


  • Less commonly caused by RSV, influenza types A and B, and parainfluenza type 3.


  • Infrequently caused by Mycoplasma pneumoniae.



Clinical Presentation



  • Barking cough, hoarseness, stridor which may be on inspiration only or biphasic.



  • Frequently begins 12 to 48 hours after symptoms of a nonspecific respiratory illness.


Diagnostic Evaluation



  • Westley croup score (published symptom scoring tool).



    • Provides an objective measure for disease severity.


  • Generally diagnosed on history and physical examination.


  • Consider lateral neck films.



    • Haziness or narrowing of subglottic area.


    • Distention of hypopharynx.


  • Consider chest radiography.



    • Narrowing of subglottic area (e.g., “steeple sign”) (see Figure 3.8).


    • Positive findings noted only in approximately 50% of studies.


Management



  • Supportive care.


  • Humidified or cooled air/gas.



    • Provides soothing vasoconstriction of airway tissue.


  • Steroids: dexamethasone 0.6 mg/kg IV/IM.


  • Oxygen and additional respiratory support/maneuvers, as needed.


  • Consider nebulized epinephrine solution.



    • Results in vasoconstriction of mucosal vasculature.






      FIGURE 3.8 • Steeple Sign. Viral croup in an 18-month-old boy. A: Lateral view of the neck shows marked subglottic tracheal narrowing (arrow) and distension of the hypopharynx (*). B: Frontal view in another patient shows narrowing of the subglottic trachea (arrows).


  • Antipyretics, if febrile, and consider IV fluid administration.


  • Consider heliox administration.



    • Increases laminar flow of gas, improves airway mechanics, and reduces respiratory workload.


  • Consult otolaryngology if patient fails to improve with standard medical therapy.



Cystic Fibrosis

Ruth DeVoogd




Etiology/Types



  • Autosomal recessive disorder.


  • Over 1,500 gene mutations identified which cause CF; some mutations cause more mild disease.



Clinical Presentation



  • Traditional signs: poor growth, large foul-smelling and oily stools, increased appetite, and frequent respiratory infections.


  • Since newborn screening for CF provides an early diagnosis, infants may present well-nourished without any respiratory involvement.


  • Pulmonary: cough, increased sputum, crackles, wheezing, shortness of breath, hemoptysis, chest pain, and hypoxemia; occasionally pneumothorax.


  • Gastrointestinal tract: periumbilical or right lower quadrant (RLQ) pain, constipation, loose stools, flatus, abdominal distention, vomiting. RLQ pain mimics appendicitis; however, is usually due to constipation or distal intestinal obstruction syndrome (DIOS).


  • Weight loss.


  • Dehydration: Hypochloremic and hyponatremic alkalosis.


  • Hyperglycemia: If has impaired glucose tolerance or CF-related diabetes.


Diagnostic Evaluation



  • Sweat chloride test: noninvasive test. Sweat chloride ≥60 mmol/L (>30 mmol/L in infants).


  • Genotype: positive for combination of mutations.


  • Pulmonary exacerbation: Chest radiography (may or may not show acute process), decline in pulmonary function test (FEV1), oxygen saturation, sputum or throat culture, high-resolution chest CT scan may be indicated.


  • Gastrointestinal complications: abdominal radiography to evaluate for constipation, DIOS, abdominal ultrasound.


Laboratory Testing



  • CBC with differential, electrolytes, BUN, creatinine, glucose, liver panel with γ-glutamyl transferase, prothrombin time (PT)/international normalized ratio (INR).


  • Hemoglobin A1C if history of CF-related diabetes or weight loss.


  • Culture for CF pathogens: expectorated sputum (preferred), throat culture, or BAL.


Management



  • Pulmonary exacerbation.



    • Airway clearance (e.g., high-frequency chest wall oscillation [vest therapy], handheld device, intrapulmonary percussive ventilator).


    • Airway hydrators (e.g., Dornase alpha [Pulmozyme], hypertonic saline).


    • Antibiotics to cover typical CF pathogens.



      • Pseudomonas aeruginosa: aminoglycosides, antipseudomonal penicillins, β-lactams, cephalosporins (third and fourth generations), and fluoroquinolones.



        • CF patients usually clear aminoglycosides more rapidly, necessitating a higher mg-per-kg dose than normal.


      • Staphylococcus aureus: antistaphylococcal penicillins, cephalosporins, TMP/SMX, some fluoroquinolones.


      • Methicillin-resistant Staphylococcus aureus (MRSA): TMP/SMX, linezolid, vancomycin, clindamycin.


      • Burkholderia cepacia complex: meropenem, plus one other (e.g., aminocycline, amikacin, ceftazidime, chloramphenicol, TMP/SMX).


    • Aerosolized antibiotics: tobramycin (Tobi), aztreonam (Cayston).


    • Oral antibiotics: depending on airway culture results and susceptibilities.


  • Abdominal pain.



    • DIOS: laxative, polyethylene glycol (Miralax, GoLytely), enema (saline or Gastrografin), stool softener.


    • Acute abdomen: surgery consult to evaluate for severe obstruction, appendicitis, intussusception.



  • Hyperglycemia.



    • Monitor blood glucose levels, treat if indicated.


    • Risk in CF-related diabetes is that patient will become hypoglycemic because of the production of insulin.



Foreign Body Aspiration

Andrea M. Kline-Tilford



Epidemiology



  • Common in children, with approximately 160 annual pediatric deaths.


  • Accounts for >17,000 emergency department visits in children <14 years of age.


Etiology/Types



  • Food items are common in all pediatric age groups.


  • Nonfood items more common in older pediatric patients (e.g., pen caps, paperclips).



Clinical Presentation



  • Acute complete obstruction results in asphyxiation and death.


  • Acute noncomplete obstruction.



    • Symptoms can vary based on size and location of partial obstruction, but often include a combination of the following: coughing, gagging, choking, wheezing, respiratory distress.


    • Decreased breath sounds over affected lung (if foreign body is in the bronchial tree position).


  • Late noncomplete obstruction.



    • Paroxysmal cough, fever and local inflammation, edema, and granulation tissue formation.


  • Three stages in noncomplete obstruction FBA.



    • Initial event.


    • Asymptomatic period.


    • Symptoms of ensuing complications.


Diagnostic Evaluation



  • History is most important.


  • Chest radiography.



    • Most helpful views include:



      • Posterior-anterior views.


      • Lateral decubitus.


      • Inspiratory and expiratory (may be difficult to obtain in infants and young children).


  • Chest fluoroscopy.


  • Chest CT scan.


  • Bronchoscopy (rigid): may be used to visualize and retrieve the object.


Management



  • Prompt diagnosis and management are critical.


  • Acute presentation.



    • Back blows/chest compressions (infant).


    • Abdominal thrusts (child).


  • Direct visualization and manual retrieval (bronchoscopy).



Lung Transplantation

Carole A. Branch



Etiology



  • Most common indications in children 0 to 18 years.



    • CF.



      • Baseline FEV1 <30% of predicted value.


      • Pao2 <55 mmHg at rest.


      • Worsening severity of hypercapnia.



        • Female pediatric patient with rapid decline in lung function.


        • Frequent respiratory exacerbations requiring hospitalization and IV therapy with no improvement in lung function.


    • Pulmonary hypertension.



      • New York Heart Association/World health Organization functional class III or IV: rapidly progressive disease, elevated right arterial pressures >15 mmHg, cardiac index <2 L/minute/m2, failing medical therapy.


    • Other indications for lung transplantation include surfactant dysfunction syndromes, CHD, chronic lung disease, bronchiolitis obliterans (BO), and pulmonary fibrosis.


Evaluation/Referral



  • Referral for transplant is usually made by a pulmonologist.


  • Evaluation process.



    • Series of diagnostic tests, procedures, and assessments.


    • Evaluation of support system and ability to follow rigorous therapy, daily monitoring, and reevaluation schedule following transplant.


    • Prescribed medical regimen.


    • Tiered allocation scores (lung allocation score).


    • Age <12 years is listed as Priority I or II based on medical condition.



      • Priority I: Respiratory failure or supplemental O2 to achieve Fio2 >50% in order to maintain O2 levels >90% OR arterial or capillary Pco >50 mmHg or a venous Pco2 >56 mmHg or pulmonary hypertension.


      • Priority II: All other candidates that do not meet criteria for Priority I.


    • Age >12 years.



      • Score from 0 to 100 calculated: based on evaluation criteria.


      • Higher score receives higher priority, based on age, diagnosis, indicators of disease severity, likelihood of successful transplant.


      • Other factors in listing for transplant include blood type, height weight, and geographical area.


    • Contraindications for lung transplant: absolute or relative.



      • Absolute contraindications include malignancy within past 2 years, immunodeficiency syndrome, hepatitis B or C with liver disease, severe neuromuscular disease, multiorgan system dysfunction.


      • Relative contraindications include pleurodesis, renal insufficiency, markedly abnormal body mass index (BMI), chronic airway infection with specified organisms, severe scoliosis, active collagen disease, mechanical ventilation, among others.


Diagnostic Transplant Evaluation



  • Organs matched by height, weight, blood type.


  • HLA antibody screening is performed.



    • Specific antibodies can be avoided if recipient has elevated antibody levels.


Postoperative Considerations



  • ICU settings with mechanical ventilation and chest tubes for first 24 to 48 hours.


  • IV antibiotics to cover previous organisms, donor organisms, and current cultures.


  • Pulmonary rehabilitation.


  • Immunosuppressive therapy: triple therapy per International Pediatric Lung Transplant Consortium.



Rejection



  • Acute rejection: Cellular rejection is highest in the first few weeks following transplant.



    • May be difficult to distinguish between rejection and infection.


    • Transbronchial biopsy with BAL surveillance performed on a regular basis based on institutional protocol.


    • Acute rejection graded from A0 (none) to A4 (severe) Grades A2 and higher are treated with high-dose pulse steroids.


    • Refractory acute rejection may be treated with augmentation of immunosuppression with monoclonal or polyclonal T-cell antibodies.


  • Chronic rejection/BO.



    • Leading cause of morbidity and late mortality 1 year after lung transplant.


    • Approximately half of all lung transplant patients are diagnosed with BO by 5 years after transplant.


    • BOS is the clinical correlate of BO.



      • Symptoms of BOS: unexplained drop in FEV1 or the forced expiratory flow (FEF) 25% to 75% on pulmonary function tests (PFTs) which does not respond to bronchodilators, plus dyspnea, wheezing.


      • Treatment: no consistently effective treatment; often consists of augmentation of immunosuppression,
        photopheresis, total lymphoid irradiation, azithromycin for anti-inflammatory effect or retransplantation.


      • Life expectancy: 1-year survival is close to 85%; median 4.3 years with better outcomes when children are 1 to 10 years of age.


Obstructive Sleep Apnea

Andrea M. Kline-Tilford



Etiology/Types



  • Most commonly due to hypertrophy of adenoids and tonsils in relation to airway diameter.


  • Also may be due to nasal obstruction, fat deposition in the pharynx, cranial facial abnormalities, or abnormal neuromotor tone.



Clinical Presentation



  • Varies with age, but typical age is toddler/preschool.


  • Loud snoring, gasping, and labored breathing during sleep.


  • May also have agitated/mobile sleep.


  • Signs of hyperactivity and inattentiveness during wakefulness.


  • School-age.



    • Agitated sleep, difficult morning arousal, daytime sleepiness, and learning problems.


Diagnostic Evaluation



  • Polysomnogram.



    • Quantifies the number and duration of airway obstructions during sleep.


    • Determines presence of hypoxia and/or hypoventilation during sleep.


    • Identifies sleep fragmentation.


  • Additional diagnostic tests to be considered:



    • ABG.


    • EKG.


    • Echocardiography.


  • Lateral neck radiography.


Management



  • Referral to otolaryngology for consideration of adenoidectomy/tonsillectomy.


  • Monitor postoperatively for hypoxia, persistent oxygen requirement, and postobstructive pulmonary edema.


  • Counsel family to monitor for return of symptoms.


  • Consider noninvasive ventilation: CPAP or BiPAP.



Pneumonia

Viswanath Gajula



Etiology



  • Community-acquired pneumonia.



    • Most common organisms by age group.



      • Neonate: group B streptococcus, Escherichia coli, Staphylococcus aureus, herpes simplex virus, Ureaplasma urealyticum.


      • Infants up to 1 year of age: RSV is most common cause.


      • 1 to 3 months of age: Streptococcus pneumoniae, Chlamydia trachomatis, Bordetella pertussis, RSV, influenza and parainfluenza virus.


      • 3 months to 5 years of age: viral, Mycoplasma, C. trachomatis, Strep. pneumoniae.


      • >5 years of age: Strep. pneumoniae, Mycoplasma pneumoniae, C. trachomatis.


    • Aspiration pneumonia.



      • Most commonly associated with oral anaerobes.


    • Health-care-associated or hospital-acquired pneumonia.



      • Most commonly associated with gram-negative bacilli, Staph. aureus.


    • Opportunistic infections in immunocompromised host.



      • Most commonly associated with Staph. aureus, gram-negative bacilli, Legionella pneumophila, Aspergillus, Pneumocystis jirovecii, CMV, herpes simplex virus.


Radiographic Patterns of Pneumonia



  • Lobar pneumonia: involving a single lobe or one of lobar segments.



  • Bronchopneumonia: involving smaller airways and surrounding interstitium.


  • Necrotizing pneumonia: Staph, aureus, Streptococcus, commonly.


  • Interstitial pneumonia: atypical bacteria, viral.



Clinical Signs



  • Tachypnea, fever, cough, respiratory distress, grunting in younger children, retractions, and hypoxemia.


  • Focal diminished breath sounds, rales (crackles), and tactile fremitus.


Diagnostic Evaluation



  • Clinical diagnosis in most cases.


  • Clinical presentation often precedes radiographic findings.



Management



  • Antibiotics based on suspected organism and age; tailored to pathogen if specimen obtained.


  • Oxygen and other respiratory support maneuvers, as needed.


  • Monitor for complications and treatment failures.


Pertussis

Viswanath Gajula




Presentation



  • Commonly in children <5 years of age.


  • May be severe in infancy, especially <6 months of age.


  • Presentation occurs in three main stages.



    • Initial symptoms (catarrhal stage: 1-2 weeks) can include rhinorrhea and cough. Fever may be mild or absent. Progression to paroxysms of cough.


    • Paroxysmal phase (1-2 weeks): often associated with a “whoop” upon inspiration, followed by a convalescent stage with persistent cough.


    • Disease in infants is often atypical and characterized by shortened or absent catarrhal stage. Gagging, gasping, and/or apnea occur often around feedings and may be life-threatening.


    • Severe pneumonia and hypoxemic respiratory failure may also occur.


    • Classic duration of cough is 6 to 10 weeks, but may be longer in older children and adults.


Diagnostic Evaluation



  • Direct fluorescent antibody testing, polymerase chain reaction testing, bacterial culture (confirmatory).


  • CBC: lymphocyte-predominant leukocytosis (WBC counts may be elevated to 50-80,000/cm3).


  • Chest radiography: Radiographic findings may be absent, or may be suggestive of small airway disease.


Management



  • Antibiotics: Macrolides including azithromycin and erythromycin are the treatment for pertussis. In young infants, azithromycin is recommended as first-line therapy.


  • Antibiotic treatment after catarrhal stage does not significantly reduce longevity or severity of disease, except possibly in cases of pneumonia.


  • Treatment is most important for preventing spread of disease.


Supportive Care



  • Hospitalization of infants with evidence of pneumonia or who are at risk for apnea.



    • Monitor and maintain adequate hydration.


    • Mechanical ventilation may be necessary in infants with significant apnea or with alveolar disease.



Pleural and Parapneumonic Effusions

Viswanath Gajula


Background



  • Inflammation of pleura secondary to adjacent pneumonia is common and often associated with pleural effusion.



  • In early stages, effusion may be transudative, but becomes exudative due to leakage of protein and inflammatory cells.


  • Empyema is accumulation of pus in the pleural space due to overgrowth of bacteria.


Etiology



  • Transudative and exudative pleural effusions.



    • Transudative: Serous, acellular fluid collection due to increased hydrostatic pressure across the vascular membrane.



      • Often associated with congestive heart failure, pericarditis, hypoalbuminemia, nephrotic syndrome, peritoneal dialysis.


    • Exudative: Due to leakage of protein and inflammatory cells, secondary to inflammatory cascade.



      • Often associated with infectious process, chylothorax, neoplasm, connective tissue disease, immunodeficiency.


  • Pathophysiology of parapneumonic effusion—three stages:



    • Exudative stage: fibrinous, uncomplicated fluid; common in the first 24 to 72 hours of effusion.


    • Fibrinopurulent stage: loculated, thick, cellular-rich fibrinous exudates; complicates to bronchopleural fistula or pyopneumothorax if left untreated; usually occurs in 5 to 10 days, may occur sooner.


    • Organizational stage: “parietal peel” formation due to fibroblast overgrowth on the parietal and visceral pleura. May compromise lung function, causes restrictive lung disease; occurs 1 to 4 weeks after the initial presentation.


Clinical Presentation



  • Similar to pneumonia or can occur as a complication of pneumonia.


  • Pleuritic pain exacerbated by deep breaths and coughing; worsening respiratory distress, persistent fevers, expiratory friction rub, diminished or “distant” breath sounds, and dullness to percussion are suggestive of effusion.


Diagnostic Evaluation



  • Chest radiography, anterior-posterior.



  • Chest radiography decubitus (affected side positioned down).



    • Evaluates mobility of fluid and layering of fluid.


  • Ultrasound or CT of chest.


  • Pleural fluid sampling for cellular and microbiological analysis.


Management (Based on Presentation, Severity, and Indications)

Jan 30, 2021 | Posted by in NURSING | Comments Off on Pulmonary Disorders
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