Resp - 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 wheezeSpiro - demonstrable obstruction, post bronchodilater FVC <0.7Severity - 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 —> dyspnoeaGas exchange —> worsening transfer. Increased dead space, reduced vent drive —> less vent —> hypercapMucous hypersecretion —> irritantsPulmonary hypertnesion —> HPV, smooth muscle hyperplasiaCo-existing systemic features - muscle wastingFrequent 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 O2Needs I&VNeeds vasopressors/inotropesLOCResp 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 txSevere 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 etcTests - 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 mucolyticsPneumococcal/flu vaccinesLTOTSmoking cessation

Question 10

When to intubate

Answer 10

Imminant resp arrestResp disressFailure or CI to NIVPersistant pH < 7.15 with NIVGCS <8

Question 11

Mechanical vent in COPD

Answer 11

COPD patients have limited exp flow rates and intrinsip PEEPIntrinsic 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 trialNo difference in mechanical ventilation