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Respiratory

1

Lecture 7

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@bitemedicine

Dr Azeem Alam, MBBS BSc (Hons)Surgical AFPGuy’s and St. Thomas’ Hospital

Content reviewed on 21/04/2020.

Learning objectives• 2 respiratory topics: Pneumothorax and Pulmonary Embolism

• Case-based discussion(s) to identify the top differentials and why

• Theory to cover pathophysiology, diagnostic criteria, investigations and

management

• Quiz (Mentimeter and multi-step SBAs)

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Case 1

History

A 23-year-old male presents with sudden onset left-sided chest pain and shortness of breath after meeting his friends.

He is usually fit and well.

On examination, there is left-sided hyper-resonance on percussion and diminished breath sounds.

Observations

HR 114, BP 120/82, RR 26, SpO2 92%, Temp 37.2°C.



PathophysiologyDefinition: accumulation of air within the pleural space

Spontaneous occurs without trauma• Primary pneumothorax: without underlying pulmonary disease• Secondary pneumothorax: complication secondary to underlying pulmonary

disease

Traumatic pneumothorax• Penetrating or blunt injury to the chest, including iatrogenic causes

Tension pneumothorax (EMERGENCY)• Intrapleural pressure exceeds atmospheric


(1)


Pathophysiology

Primary spontaneous

Pathogenesis Spontaneous rupture of a subpleural bleb

Typical presentation Young, tall, healthy, male presenting with sudden onset breathlessness and chest pain

Underlying lung disease?

No

Risk factors • Tall, slender, young (20-30)

• Smoking• Marfan syndrome• Family history• Diving or flying

(2)


PathophysiologySecondary spontaneous

Pathogenesis Rupture of damaged pulmonary tissue

Typical presentation Middle-aged patient with COPD presenting with sudden onset breathlessness and chest pain

Underlying lung disease? Yes: occurs due to ruptured bleb or bullae secondary to lung disease

Risk factors • Underlying lung disease: COPD, asthma, lung cancer

• Tuberculosis• Pneumocystis

jirovecii

(3)


PathophysiologyTension (emergency)

Pathogenesis • Air is forced to enter the thoracic cavity without any means of escape

• Results in a ‘one-way-valve’

Typical presentation Ventilated patient suddenly becomes breathless and acutely unwell

Underlying lung disease? Yes/no: usually occurs in ventilated or trauma patients

Risk factors • Mechanical ventilation

• Trauma• Iatrogenic: central

line insertion, biopsy

(4)


Clinical featuresSymptoms Signs

Sudden onset pleuritic chest pain Tachycardia and tachypnoea

Sudden onset dyspnoea Cyanosis

Hyper-resonance ipsilaterally

Reduced breath sounds ipsilaterally

Hyperexpanded chest ipsilaterally: associated with tension pneumothorax

Contralateral tracheal deviation and circulatory shock in tension pneumothorax


DifferentialsPneumothorax Pulmonary embolism Pneumonia

• SOB• Pleuritic chest pain

• SOB• Pleuritic chest pain• Haemoptysis• Pain / swelling in one leg

• SOB• Pleuritic chest pain• Productive cough• Fever

• Any age• Primary spontaneous• Secondary spontaneous• Tension

• Risk factors for thromboembolism• Obesity• Prolonged bed rest • Pregnancy • Malignancy

• Usually middle-aged or elderly

• More common with underlying lung disease

Confirmed on CXR ECG usually non-specific, but sinus tachycardia and S1Q3T3

Usually confirmed on CXR


InvestigationsImaging• Chest x-ray: visible visceral pleural edge with no lung margins peripheral to this• CT chest: gold-standard imaging method but not routinely performed

Bedside• ECG: exclude a cardiac cause

Bloods• Arterial blood gas: may demonstrate respiratory failure

Additional points• Other investigations will depend on the aetiology• ALL patients require a repeat CXR after intervention

• Tension pneumothorax: decompress prior to imaging if high clinical suspicion


Management: spontaneous • Needle aspiration: 2nd intercostal space midclavicular line

• Chest drain: 5th intercostal space mid-axillary line; triangle of safety

• Remember to always insert above the upper border of the rib

• High-flow oxygen


(7)


Management: tension• EMERGENCY: high-flow oxygen and urgent needle decompression

• Aspirate: 14G cannula at the 2nd-3rd intercostal space midclavicular line

• After decompression: chest drain insertion


Chest drain insertion

Base of axilla

Lateral edge of latissimus dorsi

Lateral edge of pectoris major

Nipple or 5th intercostal space


Chest drain insertion


Management: recurrentpneumothoracesOptions• Open thoracotomy and pleurectomy: lowest recurrence rate (1%)• VATS pleurectomy: lower morbidity than open• Surgical chemical pleurodesis: less popular now

Indications for referral to a thoracic surgeon

First contralateral pneumothorax Second ipsilateral pneumothorax

Bilateral spontaneous pneumothorax Persistent air-leak despite chest drain

High risk professions: e.g. pilots Pregnancy


Top decile question


Management: follow-upFlying• Patients can fly 1 week post check CXR as long as the pneumothorax has resolved

Diving• Avoid indefinitely until the patient has had a definitive bilateral surgical

pleurectomy, post-operative CT chest and normal lung function tests


Recap• Pneumothorax is classified as primary or secondary spontaneous, or tension

• Patients present with dyspnoea and pleuritic chest pain

• The most important initial investigation is a CXR

• Tension pneumothorax is an emergency, requiring immediate aspiration

• Management is either conservative, or with oxygen, aspiration or drainage

• There are numerous surgical options for recurrent pneumothoraces

• Patients must be offered discharge advice regarding flying and diving

Case 2

History A 65-year-old female presents with sudden onset shortness of breath and pleuritic chest pain.

She has a history of a right-sided mastectomy for breast cancer, 1 year ago.

She has a BMI of 27.

Observations

HR 125, BP 85/60, RR 28, SpO2 89%, Temp 37.7°C


PathophysiologyDefinition: obstruction of the pulmonary vasculature secondary to an embolus

• Virchow’s triad• Often secondary to deep vein thrombosis• Embolus dislodges and migrate to the lung circulation• Obstructed pulmonary vasculature ⟶ increased pulmonary vascular resistance

• Can result in arrhythmias, pulmonary infarction, cor pulmonale and cardiac arrest

Pathophysiology


Clinical featuresSymptoms SignsPleuritic chest pain Tachypnoea and tachycardiaDyspnoea HypoxiaCough or haemoptysis Deep vein thrombosis: swollen,

tender calfFever PyrexiaSyncope: a red flag symptom Hypotension: SBP < 90mmHg

suggests massive PEElevated JVP: suggests corpulmonaleRight parasternal heave: suggests right ventricular strain


DifferentialsPneumothorax Pulmonary embolism Pneumonia

• SOB• Pleuritic chest pain

• SOB• Pleuritic chest pain• Haemoptysis• Pain / swelling in one leg

• SOB• Pleuritic chest pain• Productive cough• Fever

• Any age• Primary spontaneous• Secondary spontaneous• Tension

• Risk factors for thromboembolism• Obesity• Prolonged bed rest • Pregnancy • Malignancy

• Usually middle-aged or elderly

• More common with underlying lung disease

Confirmed on CXR ECG usually non-specific, but sinus tachycardia and S1Q3T3

Usually confirmed on CXR

Case 2

History A 65-year-old female presents with sudden onset shortness of breath and pleuritic chest pain.

She has a history of a right-sided mastectomy for breast cancer, 1 year ago.

She has a BMI of 27.

Observations

HR 125, BP 85/60, RR 28, SpO2 89%, Temp 37.7°C



Wells scoreWells Two-Level PE Score

Clinical feature Points

Clinical signs and symptoms of a DVT 3.0

PE is number 1 diagnosis or equally likely 3.0

Tachycardia (>100 BPM) 1.5

Immobilisation for more than three days or surgery in the previous four weeks

1.5

Previous, objectively diagnosed PE or DVT 1.5

Malignancy with treatment within the last 6 months, or palliative 1.0

Haemoptysis 1.0


InvestigationsBedside• ECG: sinus tachycardia (most common); RBBB and right axis deviation; S1Q3T3

Bloods• ABG: may demonstrate respiratory failure

Imaging• CXR: typically normal, although a wedge-shaped opacification can be seen• ECHO: assess for right ventricular strain in massive PE

Specialist tests: depends on Wells score• CTPA is performed if high probability (Wells score > 4) or• D-dimer performed if low probability (Wells score ≤ 4)


Investigations


Further investigations: unprovoked PEInvestigations for cancer• All patients: full set of blood tests, CXR, and urinalysis• Patients > 40 years old: CT abdomen and pelvis should be considered

Investigations for thrombophilia• Antiphospholipid antibodies: considered in people who have an unprovoked PE• Hereditary thrombophilia: considered in people who have an unprovoked PE and a

first-degree relative who has had a DVT


ManagementMassive PE• Thrombolysis: e.g. alteplase

Non-massive PE• Anticoagulation:

• Oral anticoagulation: warfarin or DOAC for 3 months if provoked, or 6 months if unprovoked

• LMWH used for 6 months in cases of active cancer

Alternative treatments• Inferior vena cava filter: consider in patients with recurrent PEs, despite

anticoagulation• Surgical embolectomy: when thrombolysis has failed or is contraindicated


Recap• A pulmonary embolism presents with dyspnoea and pleuritic chest pain

• Risk factors can be remembered using Virchow’s triad

• A massive PE can cause cor pulmonale and rapid deterioration

• Initial investigations include ABG, ECG, CXR, D-dimer, CTPA and ECHO for a massive PE

• Patients with an unprovoked PE require further investigations

• Management options include thrombolysis, DOAC, LMWH or specialist interventions

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