Pulmonary Disorders Flashcards
The parents of a 9-year-old obese boy are concerned that he is falling asleep in school and seems to have decreased energy and attention. He is also reported to snore, especially when in a sound sleep. Which one of the following types of sleep apnea is most likely?
a. Obstructive
b. Central
c. Mixed
d. Hypoxic
3.1
Answer: A
Given age and habitus, the most likely explanation is OSA. Central apnea refers to loss of breathing from a primary neurologic problem and mixed apnea would be composed of both central and obstructive. The only method to know whether the child becomes hypoxic during sleep with apnea events is to complete a sleep study with oxygenation saturation monitoring.
Which one of the following diagnostic studies is best to obtain for confirming a diagnosis of OSA?
a. Airway evaluation
b. Polvsomnography
c. Chest radiography
d. pH probe
3.2
Answer: B
Although an airway evaluation may help diagnose adenotonsil-lar hypertrophy that may contribute to obstructive apnea, a sleep study or polysomnography is the diagnostic test of choice to evaluate for obstructive apnea and the degree of apnea/hypopnea episodes.
What are the most appropriate initial management strategies for a child who has definitive OSA?
a. Nutrition counseling, exercise, noninvasive ventilation for
sleep
b. Nutrition counseling, immediate tonsillectomy, cardiology referral
C. Exercise, noninvasive ventilation for sleep, chest radiography
d. Immediate tonsillectomy, cardiology referral, and chest radiography
3.3
Answer: A
Reduction of body weight would be the first adjustment to managing the sleep apnea along with noninvasive ventilation in the form of CPAP or BiPAP. Adenotonsillectomy would also be a consideration, but after appropriate diagnostic testing and first attempts at weight management.
An 8-year-old weighing 25 kg presents with a 2-day history o cough and respiratory distress, and Initialy requites supple mental oxygen. He is tachypneic with moderate retracion and has an initial SaO, of 88% with bilateral infiltrates presen on chest radiograph. He is placed on NIPPV without signit cant improvement and therefore efforts to intubate him begin The initial ABG reveals a Pao, of 70 mmHg on Fio, 0.6.
The diagnosis of ARDS is made for this child based on which of the following characteristics?
a. Acute onset, bilateral lung infiltrates, and Pao, / Fio, ratio of 200 to 300
b. Progressive onset, hyperinflation on chest X-ray, and Pao,/ Fio, ratio of <200
c. Progressive onset, hyperinflation on chest X-ray, and Pao, / Fio, of 200 to 300
d. Acute onset, bilateral lung infiltrates, and Pao,/ Fio, ratio <200
3.4
Answer: D
The definition of ARDS is based on characteristics of acute onset bilateral lung infiltrates, noncardiogenic origin, and Pao,/ Fio, ratio of <200. ALI has similar characteristics but is defined by a Pao,/ Fio, ratio of 200 to 300.
Which of the following studies will assist in confirming the diagnosis of ARDS based on the documented criteria?
a. Complete blood count
b. Bronchoalveolar lavage
C. Chest CT
d. Echocardiogram
3.5
Answer: D
Determining the etiology of cardiac versus noncardiac origin of ARDS symptoms requires at least an echocardiogram. Placement of a pulmonary artery catheter is an option to obtain more detail, but is quite invasive, and not always available in every critical care setting, so an echocardiography is often done to evaluate for underlying cardiac disease as the cause of pulmonary edema and respiratory distress.
Which of the following ventilator settings would be the mi appropriate for an 8-year-old who weighs 23 kg with hypes in the initial phase of ARDS?
a. Tidal volume 250, PEEP 10
b. Tidal volume 175, PEEP 10
c. Tidal volume 175, PEEP 6
d. Tidal volume 250, PEEP 6
3.6
Answer: B
Numerous studies have been done to determine optimal ventilator settings for managing patients with ARDS. Current evidence confirms the incidence of further injury with the use of particular ventilation strategies including high inspiratory pressures; so based on the objective of protecting the lung, low tidal volumes (7-8 ml./kg) and higher PEEP (to keep Fio2 <0.6) should be considered in the plan of care.
Despite optimization of mechanical ventilation settings in the management of the child with ARDS, it is decided to transition to high-frequency oscillatory ventilation for which of the following primary reasons?
a. Need for higher tidal volumes
b. Limiting peak inspiratory pressures
C. Ability to provide lower mean airway pressure
d. Lowering oxygenation requirements
3.7
Answer: B
High-frequency oscillatory ventilation assists in limiting peak inspiratory pressures for the purpose of protecting the lungs and offering a constant distending pressure (MAP), while avoiding overdistention of alveoli.
What dose of dexamethasone is indicated for a child with rhinorrhea, stridor, and a barky cough?
3.8
0.6 mg/kg
Percentage of CF population with nontuberculous mycobacterium (NTM)
5-20%
Percentage of population between ages of 6-10 years with Pseudomonas aeruginosa
35-40%
Percentage of CF population with Burkholderia cepacia complex (Bcc)
2.5%
Cessation of airflow through the respiratory tract for 20 seconds or longer or shorter respiratory pause associated with bradycardia or cyanosis significant enough to cause arterial hypoxemia and hypercapnia
Apnea
- 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
- Immaturity of the respiratory center (premature infants), head trauma, toxin-mediated
Central Apnea
- 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
Obstructive Apnea
Diagnostic evaluation for sleep apnea
- Polysomnography (sleep study)
- Echocardiography and/or electrocardiography (EKG) to evaluate for cardiac sequelae
Pearl of apnea
Always consider an acute life-threatening event in a young infant presenting with apnea
Result of lung injury, specifically to the alveolar capillary barrier (alveolar epithelium, capillary endothelium), which is vital in maintaining lung fluid balance
Acute respiratory distress syndrome (ARDS)
Diagnostic criteria for ARDS
- Acute onset
- Bilateral infiltrates on chest radiograph
- PaO2/FiO2 ratio of <200
- Noncardiogenic origin: pulmonary artery wedge pressure <18 mmHg or absence of clinical evidence of left atrial hypertension
Oxygen index calculation
([FiO2*MAP]/PaO2)
PaO2:SpO2
100:____
70:____
40:____
26:____
0:____
100:98
70:94
40:75
26:50
0:0
If Oxygen index >20 consider…
high-frequency oscillatory ventilation
If Oxygen index >40 consider…
extracorporeal membrane oxygenation (ECMO)
Management of ARDS
- High positive end-expiratory pressure (PEEP) to achieve FiO2<0.5-0.6
- Low tidal volume (7-8mL/kg)
- Avoid peak inspiratory pressure (PIP) >30
When is permissive hypercapnia indicated?
managing acute respiratory distress syndrome (ARDS)
Significance of high frequency oscillatory ventilation (HFVO)
- small tidal volumes
- high mean airway pressures
- limited PIPs
ARDS Pearls
- ARDS is a clinical syndrome with multiple etiologies
- Management focuses on lung-protective strategies
Tension pneumothorax clinical presentation
- tracheal deviation (contralateral)
- hypotension
- tachycardia
- cyanosis
Chest pain, dyspnea, neck pain, subcutaneous emphysema, Hamman’s sing
pneumomediastinum clinical presentation
Halo sign on x-ray may indicate what?
pneumopericardium
Air leak Pearls
- Pneumomediastinum may be associated with subcutaneous emphysema on examination
- Pneumomediastinum and pneumopericardium typically do not require intervention unless associated with marked cardiopulmonary compromise
Abnormal collection of air between the visceral and parietal pleura in the thoracic cage
Pneumothorax
Spontaneous pneumothorax triggered by menstruation and thought to be associated with thoracic endometriosis
Catamenial pneumothorax
Symptoms of a pneumothorax
- may be asymptomatic
- pleuritic chest pain (sharp and worse with inspiration) and dyspnea
- Chest pain usually resolves or changes to a dull pain within 1-3 days despite the persistence of the pneumothorax
s/s of a pneumothorax in ventilated patients
increased PIP or decreased expired tidal volume on mechanical ventilator
Management of Pneumothorax: observation
- pulse oximetry and cardiorespiratory monitoring in stable patients
- 100% oxygen delivered via face mask to “wash out” nitrogen from pleural space
Where is the needle inserted during needle aspiration in a pneumothorax?
at the second intercostal space at the midclavicular line
Where is the thoracostomy tube placed in the pleural space?
in the pleural space at the fourth, fifth, or sixth intercostal space at the mid-axillary line
Pneumothorax Pearls
- Conservative and noninvasive treatment options should be considered first in the clinically stable patient
- Tension pneumothorax is diagnosed by clinical findings and is considered a medical emergency
Intermittent asthma
- 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 3-4 times per month
- lung function tests are normal when there are no symptoms
- lung function tests are >80% of expected value and may vary slightly
Moderate persistent asthma
- symptoms occur daily and interfere with daily activities - inhaled short-acting asthma medication is used daily
- nighttime symptoms occure more than 1 time per week, but do not happen daily
- lung function tests are abnormal (>60% and <80%)
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%)
What are common findings on chest radiography in asthma?
- hyperinflation with flattened diaphragms
- peribronchial thickening
- narrowed cardiac silhouette
Acute Management of Asthma
- Oxygen (first priority)
- B-agonists (bronchial smooth muscle relaxation)
- Corticosteroids (target underlying airway inflammation)
- Anticholinergics (ipratropium bromide or Atrovent - promotes bronchodilation without affecting mucociliary clearance)
Typical pathogens found to cause bronchiolitis
Respiratory syncytial virus (RSV), adenovirus, influenza, parainfluenza, and human metapneumovirus
Physical examination findings of bronchiolitis
hypoxia, respiratory distress, diffuse crackles/rhonchi, expiratory wheeze, prolonged expiratory phase, irritability
- A form of chronic lung disease occurring in premature infants
- Result of acute respiratory disease that originates in the neonatal period
bronchopulmonary dysplasia
congenital central hypoventilation syndrome
inadequate respiratory drive as a result of genetic defect in the autonomic nervous system’s control of breathing
What gene causes congenital central hypoventilation syndrome?
PHOX2B gene
Congenital defect of diaphragm resulting in herniation of gastrointestinal contents into thoracic cavity
Congenital diaphragmatic hernia
Which side of the chest does CDH typically occur on?
Left side
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 all can be physical exam findings of?
congenital diaphragmatic hernia
What should be avoided in newborns with CDH that will introduce air into gastrointestinal tract, worsening lung compression?
bag-mask ventilation
Croup is caused by most commonly by which virus?
Parainfluenza types 1&2
What is the common finding on chest radiography in children with croup?
- narrowing of the subglottic area, aka steeple sign
Croup Pearls
- symptoms typically more prominent at night, peak in 48 hours and can last up to 1 week
- accounts for up to 90% of infectious airway obstruction
Pathophysiology of cystic fibrosis
impaired movement of salt and water across the epithelial cell wall in the exocrine glands, leading to thick sticky secretions
What leads to malabsorption and malnutrition in children with cystic fibrosis?
sticky mucus blocks pancreatic ducts, impairing excretion of pancreatic enzymes and bicarbonate, both of which are necessary for digestion of nutrients
In patients with CF, RLQ pain may mimic appendicitis; however, it is usually caused by what?
distal intestinal obstruction syndrome (DIOS)
Cystic Fibrosis Pearls
- Consider the diagnosis of CF in any patient with poor growth and frequent respiratory infections
- Newborn screening is not a diagnostic procedure and may not detect all individuals with CF
- If airway culture results are unknown or patient quite ill, treat for pseudomonas initially while waiting for culture results
- Cepacia syndrome, which occurs in patients who culture Burkholderia cepacia complex, is life-threatening. Syndrome involves rapid decline, fever, bacteremia, and necrotizing pneumonia
- Appendix is often enlarged in CF, even without appendicitis. An abdominal CT may show this enlargement, but patient may not require surgical intervention
- A child who presents with hyponatremia and hypochloremia should always be suspected of having CF
Obstructive sleep apnea Pearls
- not all snoring results in OSA
- history and physical examination alone are not reliable in distinguishing primary snoring from OSA
- OSA should be considered in children evaluated for ADD
- Long-term, untreated OSA has been associated with neurocognitive impairment, behavior problems, and cor pulmonale
Antibiotics of choice for pertussis
Macrolides - azithromycin (in young infants) and erythromycin
Pertussis Pearls
- AAP recommends antimicrobial prophylaxis for all exposed close contacts regardless of their immunization status
- Suspect pertussis in infants <4 months of age if paroxysmal cough is present
Serous, acellular fluid collection due to increased hydrostatic pressure across the vascular membrane
Transudative pleural effusion
Due to leakage of protein and inflammatory cells, secondary to inflammatory cascade
Exudative pleural effusion
Often associated with congestive heart failure, pericarditis, hypoalbuminemia, nephrotic syndrome, peritoneal dialysis. Transudative or Exudative?
Transudative
Often associated with infectious process, chylothorax, neoplasm, connective tissue disease, immunodeficiency. Transudative or Exudative?
Exudative
Findings in chest radiography with pleural effusions
blunted costophrenic angle
Pulmonary Contusion Pearls
- Most common thoracic injury in pediatric trauma patients and frequently seen with other injuries to the chest wall and to other organ systems
- primary goal is to identify other life-threatening injuries
- severe pulmonary hemorrhage may be associated with diffuse hemorrhage-related liver damage and massive hilar contusions
- increased morbidity for trauma patients with pulmonary contusions
Smoke Inhalation Pearls
- direct bronchoscopy is the diagnostic study of choice
- most children with smoke inhalation injuries do not suffer long-term respiratory sequelae
thought to be the most important cause of ventilator-induced lung injury, due to the use of high inspiratory pressure during mechanical ventilation
barotrauma
causative factor which leads to alveolar rupture and trapping of air along the interstitium, causing pneumothorax, pneumomediastinum and subcutaneous emphysema
volutrauma
trauma due to repeated opening and collapse of alveolus at low lung volumes
atelectrauma
Management in ventilator associated lung injury
- keep alveoli open during all stages of ventilation with appropriate PEEP
- reduce FiO2 to less than 0.6
- low tidal volumes of 5-6 ml/kg
Acidosis with high pCO2
primary respiratory acidosis
Acidosis with low pCO2
compensation for a primary metabolic acidosis
Acidosis with normal CO2
either uncompensated or partially compensated metabolic acidosis
Acidosis with high HCO3
compensation for a respiratory acidosis
Acidosis with normal HCO3
partial or uncompensated respiratory acidosis
Acidosis with low HCO3
primary metabolic acidosis
Alkalosis with high HCO3
primary metabolic acidosis
Alkalosis with low HCO3
compensation for a respiratory alkalosis
Alkalosis with normal HCO3
partial or uncompensated respiratory alkalosis
Alkalosis with high pCO2
compensation for primary metabolic alkalosis
Alkalosis with low pCO2
primary respiratory alkalosis
