5.2 Respiratory failure Flashcards
oxygen sats to be classed as cyanosis
<85%
pathophysiology of neonatal RDS
insufficient surfactant so alveoli collapse, can’t expand properly
does oxygen help in V/Q mismatch?
yes, but underlying pathology needs treating
typical ABG in PE
-low PaO2
-low PaCO2
-high pH
what is meant by ‘shunt’?
area of alveoli where no gas exchange occurs due to extensive alveolar damage, blood doesn’t get re-oxygenated
appearance of lungs in ARDS
heavy, red, congested, oedematous, fluid in alveoli
explain how ARDS is linked to shunt
-diffuse loss of surfactant = alveolar atelecstasis
-stiff lungs, compliance decreases
-lung volumes decrease, minute ventilation increases to compensate
-loss of hypoxic pulmonary vasoconstriction
(vasodilator prostaglandins, bradykinin, cytokines realeased, associated with inflammation)
-intrapulmonary shunt develops where there’s NO VENTILATION with respect to perfusion
management of ARDS on ventilator
100% oxygen, but also PEEP/ other adjustment
cause of central control disorder of ventilation
opioid overdose
scoliosis
sideways curvature of spine
kyphosis
abnormal rounding of upper back due to excessive outward curvature of spine
link kyphoscoliosis to decreased respiratory system compliance
reduction in chest wall compliance and lung compliance due to micro-atelecstasis
how can correction of hypoxia worsen V/Q mismatch?
removes pulmonary arteriole hypoxic vasoconstriction, so poorly ventilated alveoli now are more perfused, diverting blood from better ventilated alveoli
in what situation could type 1 respiratory failure progress to type 2?
disease progression, more areas involved
-asthma exacerbation
-end stage COPD
which 4/6 cause of hyperaemia can be fully/partially corrected by oxygen?
- low FiO2
- hypoventilation
- V/Q mismatch
- diffusion abnormalities
