Type 1 and Type 2 respiratory failure

Question 1

Define respiratory failure

Answer 1

It is when gas exchange is inadequate

Is is defined as PaO2 of <8kPa and is divided into 2 categories

Question 2

What is Type I respiratory failure

Answer 2

It is defined as the PaO2 of <8kPa with low or normal PaCO2

It is caused primarly by ventilation/perfusion (V/Q) mismatch

Question 3

Causes of Type I respiratory failure

Answer 3

Pneumonia - consolidation

Pulmonary oedema - fluid no gas exchange

PE - ischaemia

Athma - collapsed airways

Emphysema - collapsed airways

Pulmonary fibrosis

Acute respiratory distress syndrome ARDS

Question 4

What is Type II respiratory failure

Answer 4

It is when PaO2 is <8pKa with hypercapnia (PaCO2 >6kPa)

It is caused by hypoventilation with or without V/Q mismatch

Question 5

Causes of Type II respiratory failure

Answer 5

Pulmonary disease - Asthma, COPD, pneumonia, end stage pulmonary fibrosis, obstructive sleep apnoea

Reduced respiratory drive - sedative drugs, CNS tumour, or trauma

Neuromascular disease - myasthenia gravis, cervical cord lesion, guillian barree,

Thoracic wall disease - flat chest, kyphoscoliosis

Question 6

Symptoms of respiratory failure

Answer 6

symptoms of underlying disease + hypoxia and/or hypercapnia

Question 7

symptoms of hypoxia

Answer 7

Dysponea

Restless

agitation

confusion

central cyanosis

If long standing hypoxia - polycythaemia, pulmonary oedema, cor polmonale

Question 8

symptoms of hypercapnia

Answer 8

Headache

peripheral vasodilation

tachycardia

bounding pulse

tremor/flap

papilloedema

confusion

drowsiness

coma

Question 9

Investigating respiratory failure

Answer 9

Aim is to identify underlying cause

Bloods: FBC, U&E, CRP, ABG

CXR

Microbiology - sputum and blood culture (if febrile)

Spirometry - COPD, neurmusclar disease, guilleen barre

Question 10

Management of type I respiratory failure

Answer 10

Treat cause

Give oxygen 35-60% by facemask to correct hypoxia

assisted ventilation if PaO2 <8kPa despite 60% O2

Question 11

Management of type II respiratory failure

Answer 11

Treat cause

Controlled oxygen therapy here

start 24% oxygen with care but dont leave hypoxia not treated

Recheck ABG after 20min, if PaCO2 is steady or low increase Oxygen if PaCO2 risen >1.5kPa and still hypoxic consider assited ventilation

If this fails consider intubation and ventilation