Pulmonary EmbolismDr Felix Woodhead

Consultant Respiratory Physician

Pulmonary Embolism

• Part of VTE

• Potentially fatal

• Can complicate hospital admission

• Preventable

• Tests poor

Risk factors

• Surgery– Abdominal

– Lower limb

• Obstetric

• Malignancy

• Previous VTE

Clinical Probability

• Wells score

• Geneva criteria

• Is a major risk factor present? =1

• Is there no other explanation? =1

• Score:– 2: High probability

– 1: Intermediate probability

– 0: Low probability

D-dimer

• Only useful if NEGATIVE

• ↑ by many things (including pregnancy and infection)

• Used only after assessment of clinical probability– Not used if high clinical probability

Imaging

• CTPA in most places

• V/Q – only if normal CXR and no cardiopulmonary disease

– Intermediate scan requires follow-up imaging (CTPA)

• Doppler USS if DVT (no need for resp imaging)

Screening for thrombophilia/cancer

• Thrombophilic abnormality occurs in 25-50% VTE

• Usually interacts with environment (esp oestrogens), and risk is multiplicative

• Does not predict risk of recurrence

• Screen for cancer with bloods, clinical picture and CXR only

Treatment

• Thrombolysis only in massive PE (circ collapse)

• Thrombolysis controversial if RV impairment

• Anticoagulate with LMWH then warfarin for– 4-6/52 if associated with temporary risk factor

– 3/12 if no risk factor (BTS), US recommend 6/12

• ?unfractionated heparin initial bolus

Pulmonary Arterial HypertensionDr Felix Woodhead

Consultant Respiratory Physician

Findings

• Exertional breathlessness

• Exertional chest pain and presyncope

• Normal radiology if idiopathic

• Normal PFTs if idiopathic

• ↑ systolic PAP on echo only if TR

Defined by RHC

• mPAP – > 25 mmHg at rest (normal 12-16 mmHg)

– > 30 mmHg on exertion

• Cardiac Output

• Cardiac Index (=CO/height2)

• Pulmonary Vascular Resistance

Causes• Left ventricular impairment (PCWP > 15)

– LVF

– Mitral valve disease

• Increased pulmonary blood flow (L→R shunt) → Eisenmenger’s syndrome

• Hypoxaemia (cor pulmonale)

• Chronic Thromboembolic (CTEPH)

• HIV

• CTD (SSc etc)

• Idiopathic (IPAH)

Investigations

• PFTs

• CTPA

• Echo (± bubbles)

• 6 minute walk

• Right Heart Catheter

• (traditional) pulmonary angiogram

Treatment• Treatment of associated causes

– LV disease

– O2 for cor pulmonale

• Warfarin (for all)

• Calcium channel blockers – little used now

• Endothelin receptor blockers – Bosentan, sitaxentan

• PDE4 antagonists – Sildenafil etc

• Prostaglandins

– Nebulised

– Continuous IV via Hickman line

Sleep medicine

Dr Felix Woodhead

Consultant Respiratory Physician

Obstructive sleep apnoea/hypopnoea Sx• Periodic reduction of airflow at night

• Caused by ostruction (cf central apnoea) due to reduced muscle tone in a suceptible airway (obesity)

• Apnoea : no airflow for 10 s

• Hypopnoea : ≤ 50% airflow in 10 s

• AHI (apnoea/hypopnoea index) = no of events/hr

• AHI

– 5-14 = mild

– 15-30 = moderate

– >30 = severe

Symptoms

• Sleepiness (daytime hypersomnolence)– Epworth Sleepiness Score

• Witnessed apnoeas

• Nocturia

• Hypertension

• Reduced concentration

• Reduced libido

• Tendency to cor pulmonale, esp in COPD

Diagnosis

• Overnight oximetry– Good screening esp in obese

– Cannot be used to exclude OSAHS

• Limited PSG– Useful initial test in young, non-obese

• Full PSG

Treatment

• Only if symptomatic

• AHI >15, desat index >10/hr

• Nasal CPAP– fixed

– Autotitrating device

Domiciliary NIV

• For ventilatory failure

• Other treatments

– Low flow O2 (with care)

– Treatment of sleep disordered breathing

• Hallmark of ventilatory failure is ↑pCO2