Red Book - COPD

Question 1

Define COPD

Answer 1

GOLD definitions:

Common, preventabel and treatable disease

Characterised by persistent respiratory symptoms 

and airflow limitation

Due to alveolar/airway abnormalities

Usually due to exposure to noxious particles and gases

Question 2

Describe briefly the pathophysiology and the key noxious stimulants

Answer 2

Expiratory airflow is due to:

Small airway inflammation - obstruictive bronchiolitis
Parenchymal destruction - emphysema

Stimulants:
	Smoking
	Air pollution
	Occupational exposure
	a-1 antitryosisn deficiency

Question 3

Classifcation of COPD

Answer 3

GOLD class, based on FEV1 (post bronchodilator)

1 - mild - >80%
2 - mod 50-79%
3 - severe 30-49%
4 - very severe <30%

of Predicted

Question 4

Diagnosis and severity og COPD

Answer 4

Symptoms - cough with exertional breathless
sputum production
frequent winter infections
wheeze

Spiro - demonstrable obstruction, post bronchodilater FVC <0.7

Severity - GOLD, MRC scale
Chronic hypoxia, hypercapanoea, pulmonary hypertension, failure, polycythaemia

Question 5

Pathophysiology of COPD

Answer 5

Airflow limitations and gas trapping —> hyperinflation —> dynamic on exercise —> dyspnoea

Gas exchange —> worsening transfer.
Increased dead space, reduced vent drive —> less vent —> hypercap

Mucous hypersecretion —> irritants

Pulmonary hypertnesion —> HPV, smooth muscle hyperplasia

Co-existing systemic features - muscle wasting

Frequent exacerbations from viruses/bacteria/environment

Question 6

When to bring to ITU

Answer 6

Persistant/worsening hypoxia and worsening acidosis (pH <7.25) desite NIV and O2

Needs I&V

Needs vasopressors/inotropes

LOC

Resp distress not resonding to TX

Question 7

Indications for NIV during exacerbation

Answer 7

Worsening resp acidosis (PaCO2>6.5, pH < 7.35 despite medical tx

Severe acidosis <7.25. (Should have NIV in a level2/3 setting with I&V near)

Ceiling of treatment for non ICU candidates

Question 8

Managing an exacerbations

Answer 8

ABCDE etc

Tests - Bloods - FBC, U&E, LFT, CRP, Clotting, ABG
Micro - Sputum and blood cultures
CXR
ECG/Echo

Treatment:
	Neb salbutamol
	Neb ipratropium
	Steroids 
	Abx if needed
	Carbocisteine if cough

Resp Support:
	O2 88-92%
	Use of venturi devices
	NIV
	I&V

Question 9

Preventitive measures

Answer 9

Optimise broonchodilators and mucolytics

Pneumococcal/flu vaccines

LTOT

Smoking cessation

Question 10

When to intubate

Answer 10

Imminant resp arrest

Resp disress

Failure or CI to NIV

Persistant pH < 7.15 with NIV

GCS <8

Question 11

Mechanical vent in COPD

Answer 11

COPD patients have limited exp flow rates and intrinsip PEEP

Intrinsic PEEP: decreases venous return —> low BP
Increased PVR —> Right heart strain
Barotrauma/volutrauama

Therefore:
	Reduce RR
	Prolong the I:E ratio
	Reduce breath stacking
	Accept hypercapnoea (may rasied PVR)

Extrinsic PEEP, below iPEEP

Treat bronchospasm

Question 12

Evidence for acetazolamide

Answer 12

DIABOLO trial

No difference in mechanical ventilation