Resipiratory Failure

Question 1

How is respiratory failure defined

Answer 1

PaCO2 over 50mmhg and
PaO2 below 60mmhg

Or

Arterial Sp02 below 90%

Question 2

List the 5 anatomical of causes of respiratory failure in the paediatric population

CC AIR

Answer 2

Acquired extra-thoracic airway causes

Congenital extrathoracic airway causes

Intrathoracic airway and lung causes

Respiratory pump causes

Central control causes

Question 3

What are the Acquired extra-thoracic airway causes of paediatric respiratory failure (3)

Answer 3

Infections
(retropharyngeal abscess, croup, bacterial tracheitis, peritonsillar abscess)

Trauma (postextubation croup, thermal burns, foreign-body aspiration)

Narrowed airways (hypertrophic tonsils and adenoid)

Question 4

What are the Congenital extrathoracic airway causes of paediatric respiratory failure

Answer 4

Subglottic stenosis

Subglottic web or cyst

Tracheomalacia
softening of the tracheal cartilage which can lead to tracheal collapse and airway obstruction. Long-term intubation can lead to structural damage and weakening of the cartilage.

Craniofacial anomalies( cleft lip/ palate)

Question 5

Intrathoracic airway and lung causes of respiratory failure

Answer 5

Acute respiratory distress syndrome (ARDS)

Asthma

Bronchiolitis

Pneumonia

Pulmonary edema

Pulmonary embolus

Sepsis

Question 6

Respiratory pump causes of paediatric respiratory failure

Answer 6

Diaphragmatic hernia

Flail chest

Duchenne muscular dystrophy

Guillain-Barré syndrome

Myasthenia gravis

Question 7

Central control causes include the following:

Answer 7

CNS infection

Stroke

Traumatic brain injury

Question 8

Pathophys mechanisms of respiratory failure

Answer 8

(V)/ (Q) Mismatch !!!

• above 1= path perfusion
• below 1= insult vent

Intrapulmonary shunt !!! Increased dead space and mixing of ox & deox blood

Hypoventilation !!! Reduced o2 sat and increased CO2

Abnormal diffusion of gases at the alveolar-capillary interface

Reduction in inspired oxygen concentration d/2 environment

Question 9

Examples of extra thoracic airway differences in children that increases the risk of respiratory failure ( 3/4)

Answer 9

Neonates and infants are obligate nasal breathers until of 2-6 months because of the proximity of the epiglottis to the nasopharynx. Nasal congestion can lead to clinically significant distress in this age group.

smaller airway in infants and children younger than 8 years compared with older patients.

Infants and young children have a large tongue that fills a small oropharynx.

The larynx is opposite vertebrae C3-4 in children versus C6-7 in adults.

The epiglottis is larger and more horizontal to the pharyngeal wall in children than in adults. The cephalic larynx and large epiglottis can make laryngoscopy challenging.

Infants and young children have a narrow subglottic area. A small amount of subglottic edema can lead to clinically significant narrowing, increased airway resistance, and increase the breathing load

Adolescents and adults have a cylindrical airway that is narrowest at the glottic opening.unlike the cone on n paeds

adenoidal and tonsillar lymphoid tissue is prominent and can contribute to airway obstruction.

Uncorrected congenital anatomic abnormalities (eg, cleft palate, Pierre Robin sequence) or acquired abnormalities (eg, subglottic stenosis, laryngomalacia/tracheomalacia) may cause inspiratory obstruction.

Question 10

What makes up the extrathoracic opening

Answer 10

The area extending from the nose through the nasopharynx, oropharynx, and larynx to the subglottic region of the trachea constitutes the extrathoracic airway. This area differs in pediatric versus adult patients in 8 respects

Question 11

What is the intrathoracic airway

Answer 11

conducting airways and alveoli,
the interstitia
the pleura
lung lymphatics, and the pulmonary circulation.

There are 6 noteworthy differences between children and adults in this area

Question 12

6 differences in paediatric intrathoracic airway

Answer 12

Paediatric pop has fewer and smaller alveoli than do adults. The number exponentiates from approximately 20 million at birth to 300 million by 8 years of age Therefore, infants and young children have a relatively small area for gas exchange

Collateral ventilation is not fully developed in children therefore, atelectasis is more common.
During childhood, anatomic channels form to provide collateral ventilation to alveoli.
-betw/adjacent alveoli
-betw/ bronchiole and alveoli
-betw/adjacent bronchioles.
allows alveoli to participate in gas exchange even in the presence of an obstructed distal airway.

Smaller intrathoracic airways are more easily obstructed than larger ones. With age, the airways enlarge in diameter and length.

Infants and young children have relatively little cartilaginous support of the airways. As cartilaginous support increases, dynamic compression during high expiratory flow rates is prevented.

Residual alveolar damage from chronic lung disease of prematurity or bronchopulmonary dysplasia decreases pulmonary compliance.

Question 13

What is the respiratory pump

Answer 13

1) nervous system with central control (ie, cerebrum, brainstem, spinal cord, peripheral nerves)
2) respiratory muscles
3) chest wall.

5 features mark the difference between the pediatric and adult population:

Question 14

Differences in paediatric respiratory pump they increases the risk of respiratory failure

Answer 14

The respiratory center is immature in infants and young children and leads to irregular respirations and an increased risk of apnea.

The ribs are horizontally oriented. During inspiration, a decreased volume is displaced, and the capacity to increase tidal volume is limited compared with that in older individuals.

The small surface area for the interaction between the diaphragm and thorax limits displacing volume in the vertical direction- reduced VC

The musculature is not fully developed. The slow-twitch fatigue-resistant muscle fibers in the infant are underdeveloped.

The soft compliant chest wall provides little opposition to the deflating tendency of the lungs. This leads to a lower functional residual capacity in pediatric patients than in adults, a volume that approaches the pediatric alveolus critical closing volume.

Question 15

Signs and sx of respiratory failure

Answer 15

History: ppt factors (infec, congenital malformations, premature birth etc

Sx of sepsis, URTI,

Physical exam: avoid interfering with the patient’s mechanisms for compensation. Children often find the most advantageous position for breathing, which can be a helpful diagnostic clue

Question 16

Inspection in resp failure

Answer 16

Children with respiratory distress commonly sit up and lean forward to improve leverage for the accessory muscles and to allow for easy diaphragmatic movement. Children with epiglottitis sit upright with their neck extended and head forward while drooling and breathing through their mouth.

look for central or peripheral cyanosis.

lethargic, irritable, anxious, or unable to concentrate d/2 inability to breath

Assess respiratory function ‘!!!!!!!

Paradoxical chest wall movement(abdom breathing)

Accessory muscle use and nasal flaring

Suprasternal and intercostal retractions
-Creates high negative pleural pressures are required to overcome airway obstruction or stiff lungs.

Question 17

Signs during assessment of respiratory lung function during respiratory failure

Answer 17

Bradypnea is most often observed in central control abnormalities.

Slow and large tidal volume breaths minimize turbulence and resistance in significant extrathoracic airway obstruction (eg, epiglottitis).

Tachypnoea: intrathoracic airway obstruction
The fast and shallow breathing decreases dynamic compliance of the lung.

Question 18

What is paradoxical breathing

Answer 18

D/2 instability of the chest wall & absent intercostal muscle use.
diaphragm contracts and pushes abdominal contents out causing the chest wall retracts inward instead of expanding normally. compensatory pattern for a very young infant with chronic lung disease or decreased chest wall compliance.

Question 19

Signs during Auscultation in respiratory failure

Answer 19

stridor (High pitched an inspiratory sound suggesting difficult breathing
wheezing (expiration)
crackles( alveolar consolidation in infection
decreased breath sounds (pleural effusion).

Question 20

Dx of respiratory failure

Answer 20

Guillian barre

Ludwig angina

Neuromuscular disorders

Question 21

Dg

Answer 21

Clinical exam

Lab
( ABG: actually defines respiratory failure 
PaCO2 greater than 50 mm Hg
PaO2 less than 60 mm Hg
arterial oxygen saturation less than 90%

CBC: polycythemia in Long standing hypoxemia

X-ray: 
foreign body, 
hyperinflation (asthma) 
Consolidation 
Cardiomegaly
Asymmetric lung expansion (bronchial obstruction)

Testing for intrapulmonary shunts

Question 22

Mamagement of respiratory failure

Answer 22

Endotracheal intubation is to maintain airway patency in certain cases (eg, epiglottitis, thermal burns to the airway, severe croup)

Extrathoracic airway support

• systemic CS reduce oedema
• nebulisers
• liquifies

Respiratory support

• O2 therapy
• Continuous positive airway pressure
• Noninvasive positive-pressure ventilation

Question 23

Medication for respiratory failure

Answer 23

depends on cause

Lung surfactant

• stabilising alveoli and reduce surface tension to make breathing easier
• used in Neonatal Resp Distress

Pulmonary vasodilator to rx pulmonary HTN
-NO

Corticosteroids and beta agonists for asthma to reduce oedema and dilate bronchi

AB for pneumonia

Diuretics for pulmonary oedema and LHF