resspiratory failure lms

Question 1

type 1 respiratory failure

Answer 1

hypoxaemia
gas exchange failure

Question 2

type 2 failure

Answer 2

hypercapnia
ventilatory failure

Question 3

caauses of hypoventilation

Answer 3

brainstem - stroke, encephalitis, drugs
spinal cord - trauma
anterior horn cell - motor neurone disease, poliomyelitis
nerves - GBS
neuromuscular junction - myasthenia gravis
muscle - muscular dystrophies, muscle relaxants
chest well - obesity, kyphoscoliosis
lung and airways - COPD, brnchiectasis, thymoma

Question 4

factors decreasing respiratory drive

Answer 4

sedatives, opioids, anaasthesia
sleep and sleep disruption
excess O 2
rare = diseases of medulla, eg. stroke, trauma, encephalitis

Question 5

sleep hypoventilation

Answer 5

sleep in a healthy individual: basal metabolic rate declines, alveolar ventilation declines more, PaCO2 rises by 2-4mmHg
PaCO2 rises by > 10mmHg = sleep hypoventilation

Question 6

diagnosis of type 2 resp failure

Answer 6

variable symtpoms
orthopnoea - cant lie flat
thoracic abdominal paradox
shortness of breath
alteration in rate and depth of breathing
accessory muscle use

Question 7

symptoms and signs of CO2 retention

Answer 7

poor sleep quality
morning headahce
day time fatigue and sleepiness
cenrtral nervous system - decreased conscious state

Question 8

invasive ventilation

Answer 8

ETT/tracheotomy

Question 9

non-invasive ventilation

Answer 9

negative pressure ventilation (eg. during polio epidemics)
positive pressure ventilators (e.g VPAP, bipap)

Question 10

why not CPAP

Answer 10

doesnt ventilate - splints upper airways and bronchial airways

Question 11

nocturnal NIV

Answer 11

non invasive ventilation
improves outcomes in chronic type 2 resp failure

Question 12

VQ mismatch

Answer 12

Question 13

ddx of hypoxia

Answer 13

atmospheric oxygen presssure eg. altitude
shunt (pulmonary arteriovenous fistulas, congenital heart disease)
hypoventilation (ie. secondary to severe type 2)

Question 14

acute lung disease causing hypoxia

Answer 14

infections, cardiac failure (pulmonary oedema
pulmonary embolism
exoossure to inhaled toxic substances

Question 15

chronic lung disease causing hypoxia

Answer 15

COPD, cystic fibrosis, interstitial lung dissease, pulmonary vascular disease

Question 16

treatment of type 1 respiratory failure

Answer 16

supplimental oxygen
CPAP/NIV
invasive ventilation
ECMP (extra corporeal membrane oxygenation)
treat underlying condition

Question 17

nasal cannula

Answer 17

convenient - patient can still talk and eat and drink
variable FiO2
low oxygen requirements including home use
usually dont go higher than 4L/min

Question 18

hudson mask

Answer 18

5-10L/min flow
higher FiO2 40-60%

Question 19

non rebreather mask

Answer 19

reservoir bag collects. exhaled gas
40-90% FiO2
inadequate humidifications

Question 20

patients with chronic lung disease

Answer 20

severe chronic lung diease when CO2 is chronically raised, ie. loss of most stimulus to ventilation form CO2
hypoxic drive to ventilation becomes very important
ie. arterial hypoxaemia becomes the cheif stimulus to ventilation
high oxygen concentrations to relieve hypoxia can cause depressed breathing

Question 21

ventilation can be dangerous for

Answer 21

people with chronically raised Co2 levels eg. acute on chronic COPD

Question 22

venturi devices

Answer 22

reliable FiO2
humidification not necessary

Question 23

HFNC

Answer 23

high flow nasal cannula
heats, humifidies and delivers high flow oxygen
30-60L/min
FiO2 up to 100%
well tolerated due to humidification
minimal dilution with room air (precise FiO2)

Question 24

blood pH in patients with hypercapnia

Answer 24

normal pH suggests chronic CO2 retention while a low pHraises concern for acute or acute on chronic CO2 retention, which requires immidiate intervention ie. respsiratory acidosis