24. Acute and chronic respiratory failure.

Question 1

what is acute and chronic respiratory failure ?

Answer 1

inability of the respiratory system to adequately deliver oxygen or remove carbon
dioxide from the body

defined as a PaO₂ of < 60 mmHg/8 kPa
and
defined as a PaCO₂ of > 45 mmHg/6 kPa

resulting in respiratory acidosis

acute : pH <7.3
chronic PH 7.3-7.5 = there has to be metabolic compensation by the kidneys

Question 2

what are the types of respiratory failure ?

Answer 2

hypoxermic - due to inadequate oxygenation

occurs in 4 situations

1) V/Q mismatch - blood travels to alveoli that is not ventilated 
or dead space 
asthma 
pulmonary edema 
ARDS

2) intrapulmonary shunts - blood entering the arterial system without entering the ventilated lung parenchyma
=MOST Important feature 100 percent oxygen does not resolve hypoxemia
pac02 is normal normal or low

3) hypoventilation -
po2 does high high pac02
hypoventilation always leads to paco2

4) diffusion defects

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hypercapneic

inadequate ventilation
due to : increased dead space ventilation , reduced respiratory dive due to CNS dysfunction

Question 3

aetiology of respiratory failure in infants ?

Answer 3

not due to copd
but mostly congenital and infectious process

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chronic -

1) congenital heart disease
2) lower airway obstruction - asthma

muscular dystrophy

end stage cystic fibrosis

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acute - upper airway obstruction  
1) croup (nebuliser epinephrine ,corticosteroids) 
2) anaphylaxis 
3) aspiration of foriegn body 

lower airway obstruction
bronchiolitis (nasla suctioning ,bronchodilator)

parenchymal disease
1) pneumonia
pulmonary edema - cardiogenic / non cardiogenic

diorder to control of breathing - increased intracranial pressure
poisoning or overdose
neuromuscular disease - Gillian barre

Question 4

what are the symptoms of upper airway obstruction ?

Answer 4

stridor
seal like cough
hoarseness of voice

Question 5

what is the clinical symptoms of lower airway obstruction ?

Answer 5

wheezing - typically expiratory

prolonged expiratory phase

Question 6

what re the clinical symptoms of parenchymal disease ?

Answer 6

grunting
crackles
decreased breath sounds

Question 7

what are the signs and symptoms distinguishing between respiratory distress and failuree

Answer 7

distress 
tachypnea 
increased effort for breathing
tachycardia 
pallor
anxiety agitation 

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resp failure 
bradypnea 
decreased effort - apnea 
bradycardia 
cyanosis
lethargy , unresponsive , coma

Question 8

what is the diagnosis of respiratory failure ?

Answer 8

pulse oximetry

BGA - gold standard

Question 9

what is the treatment for respiratory failure ?

Answer 9

Severe hypoxemia, hypoventilaton, or apnea

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1) immediate assistance with bag & mask ventilation

Heated high-flow nasal cannula (HHFNC):
◦ used in infants and young children more frequently
◦2L/min in infants and greater than4L/min in children are considered high flow

BiPAP / CPAP
Administration of mechanical ventilatory support
without using an invasive artificial airway
provide positive pressure breathing through a:mouthpiece, nasal mask, facemask

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2. Intubation and controlled mechanical ventilation

two useful methods for calculating the correct size of ETT for a child:
1. Measuring the child’s height with a special ‘Broselow tape’ and then reading the corresponding ETT size on the tape

2. Children older than 2 years, using the formula: ETT size = (16 + ages in years) /4

ECMO (Extracorporeal membrane oxygenation)
Central venous blood is directed out of the body, oxygenated, warmed and returned back