Respiratory

Obstructive lung disease

  • An airways rather than parenchymal problem with expiratory airways obstruction
  • Normal/increased Vital capacity, Reduced FEV1.0, Reduced FEV/FVC
  • CXR - Hyperexpanded lungs. Transfer factor reduced with emphysema
  • Type 1 and later disease Type 2 Respiratory failure
  • Pursed lips breathing, intercostal recession, breathless, hyperinflated "barrel" chest, loss of cardiac dullness

Smoking

Smoking is highly addictive and damaging. Always offer help to quit. Document it. Signs consistent with a high Level of addiction include smoking first cigarette within 30 mins of waking and smoking > 25/day. Patients often less than truthful in their intake as they are aware of the stigma that goes with smoking these days. Smoking related diseases include cancers, vascular disease and other
  • Cancers - Lung - all types, Oral cavity, Laryngeal, Oesophageal, Pancreatic
  • Vascular disease - MI/Angina, Stroke, Peripheral vascular disease
  • Aggravates - Goodpasture's syndrome, Grave's eye disease, Chickenpox pneumonitis

Therapies are available - any /all worth trying. Complementary can be tried - Hypnotherapy, Acupuncture. Whatever works. Nicotine replacement therapies (NNTs) - gum, inhalers, nasal sprays, patches, lozenges are all available. In resistant cases Bupropion SR (Zyban) may be used. This is a Noradrenaline and dopamine reuptake inhibitors. May be used with patch. C/I with epilepsy

Nicotine Withdrawal is accompanied by a craving for nicotine, Anger, restlessness, anxiety. Patient is Irritable, possibly increased appetite, Poor concentration. Most resolve by 30 days. Weight gain 2-4 kg is typical

Asthma

Introduction
  • Asthma is a chronic respiratory illness with acute exacerbations with expiratory wheeze and reversible airways obstruction.
  • Reversibility over time and with treatment which can be established by history, examination, PEFR records and spirometry. Reversibility is key to the diagnosis and differentiation from other obstructive diseases most notably COPD.
Aetiology
  • Asthma is increasing worldwide and each year in the UK 1000-2000 people die of Asthma.
  • It is commoner in those with hay fever, urticaria and eczema and raised IgE and eosinophils - Allergic asthma.
  • It is this rise in 'allergy' that may account for the overall rise in asthma incidence.
  • The aetiology of asthma is incompletely understood. It is possibly due to excess of Th2 > Th1 in nasal and bronchial mucosa. Th2 lymphocytes secrete cytokines, inducing the production of IgE. Th2 lymphocytes cause maturation and recruitment of mast cells and eosinophils. At a pathology level there is thickening of the lamina reticularis.
  • Eosinophilia may be seen in bronchial biopsies. Curschmann's spirals containing eosinophils and Charcot-Leyden granules suggest steroid responsiveness
Preciptants
  • Asthma may be precipitated by factors such as cigarette smoke, house dust mite allergen, viral infections, Exercise and Emotional stresses, cold air and Irritant gases as well as perfume and deodorants, drugs - NSAIDs, Aspirin (associated with Nasal polyps), Beta blockers, Tartrazine ( a colourant), Aspergillus spores and other chemicals - see occupational asthma
  • The response to precipitant may be early bronchospasm post exposure to precipitant and/or delayed bronchospasm is seen in 1/3rd even up to 10 hours after initial exposure
Clinical
  • The main symptoms include episodic expiratory wheeze and dyspnoea with prolonged expiratory phase. There may be chest tightness and cough which is quite often nocturnal.
  • Asthma has been classified into Intrinsic asthma where there is no allergic component or atopy. Patients do not have evidence of raised IgE. Seen more in late onset asthma. On the other side is extrinsic asthma where allergy and atopy play a key role. Allergic asthma is commoner in children and young adults and there is an elevated IgE
  • Investigations include FBC and U&E and CRP /ESR normal - usually normal unless infective component. Eosinophils and IgE may be elevated with extrinsic asthma. PEFR shows variability with time and treatment. Predicted peak flow should be assessed from standard charts. Diary of PEFR readings can show variability. Reversibility can be tested with an improved FEV1.0 by > 15% after 2 weeks of Prednisolone 30 mg od. CXR will in most cases be normal. Histamine and Methacoline challenges are uncommonly used and not to be used in brittle asthmatics. Skin prick testing may be used to identify possible allergens to avoid. Aspergillus antibodies if eosinophilia or CXR shadowing

Management of Asthma: Drugs commonly used include

  • Standard beta agonist e.g Salbutamol inhaler
  • Long acting beta agonist (LABA) e.g salmeterol
  • Inhaled corticosteroids
  • Leukotriene receptor antagonist
  • Oral or IV Corticosteroids
  • IV Beta agonists
  • IV Aminophylline

Standard escalation process for Chronic Asthma

  • Step 1 Mild intermittent Asthma: Short acting beta agonist as required such as a Salbutamol inhaler. Teach inhaler technique.
  • Step 2 Regular preventer medication: Add Inhaled corticosteroid 200-800 mcg/day - start at 400 mcg/day e.g Beclametasone, Budesonide, Fluticasone. Advise to rinse mouth after to avoid oral candidal infection or hoarseness.
  • Step 3 Add on therapy - Long acting beta2-agonist (LABA)e.g Salmeterol and/or Increase inhaled steroid to 800 mcg/day if still not controlled. No response to LABA then stop it, continue steroid and consider SR Theophylline or Leukotriene receptor antagonist (Montelukast, Zafirlukast).
  • Step 4 Persistent poor control - Increase inhaled steroid dose to 2000 mcg/day - Add Leukotriene receptor antagonist/ Oral beta2 agonist tablet/SR Theophylline
  • Step 5 Continuous or frequent oral steroid usage : Increase inhaled steroid dose to 2000 mcg/day to minimise oral steroids. Consider other treatments - refer to specialist. Methotrexate has been used in severe Asthma.
  • Patient involvement and education is fundamental at all stages.

Acute Severe Asthma (Status Asthmaticus)

Introduction

  • No patient with acute severe asthma who gets to hospital still breathing should die. Monitor patients at all times. If not improving then inform intensivists early.
  • Most asthmatics never need to come to the emergency department and have good control of their asthma in the community.
  • However asthma kills and all asthma attacks that warrant hospital assessment must treated cautiously. If admission neded then regular review of clinical status and escalation of therapy are paramount
  • Keep the unwell patient in sight on the Acute assessment unit or in A&E or HDU. Close and regular observation and senior input are key
  • Always ensure breathless patient accompanied at all times e.g in x-ray dept.

Fatalities

  • Death is due to tiredness, bronchoconstriction, mucus plugging and ventilation/perfusion mismatches
  • In fatal asthma attacks extensive mucus plugging of the airways is typically found in autopsies

Clinical - worrying signs that need escalation

  • Severe dyspnoea and expiratory wheeze
  • Inability to complete a full sentence
  • A reduced PEFR < 33% or even worse the inability to blow a PEFR
  • Tachycardia > 120/min or Bradycardia
  • SaO2 < 92% or PaO2 < 8 KPa or PaCO2 4.6-6.0 kPa normalises from being low is a worrying sign
  • Hypotension
  • Visibly tired and exhausted
  • Patient in extremis – do not wait for these signs to appear before getting intensivists
  • A silent chest - wheeze stops as respiratory volume shifted reduces
  • Confusion, Cyanosed, Comatose and drowsy.
  • Pulsus paradoxus - there is a BP drop > 20 mmHg during inspiration which suggests major attempts at shifting gas and will reduce in the tiring patient.
  • Cardiorespiratory arrest

Investigations

  • May show an elevated WCC suggesting infection and a possible role for antibiotics though many of these are viral.
  • CXR in all but the mildest cases - consolidation, collapse, pneumothorax, infiltrates and other pathology.
  • Check ABG if SaO2 on air < 92% or needing oxygen or tiring
  • Record PEFR is possible and compare with normal value if known

Management (Liaise closely with Intensivists)

  • Ensure patient sitting up, comfortable as possible, reassurance, hydration, encourage slower and deeper respirations
  • Give High FiO2 40-60%
  • Nebulised salbutamol 5 mg repeated every 15-20 minutes
  • Nebulised ipratropium bromide (Atrovent) 0.5 mg 4 hourly
  • Prednisolone 40-50 mg stat orally and/or 100 mg IV Hydrocortisone qds
  • Ask anaesthetists to review if failing to improve with initial therapy or have concerns
  • IV MgSO4 1.2-2 g (8 mmol) in 20 minutes may help to improve FEV1
  • Consider IV aminophylline or IV salbutamol with ECG monitoring
  • Close observation at all times as rapid deterioration is possible
  • Antibiotics not necessarily indicated unless clear evidence of infection
  • Hydration is important so give IV fluids.

Anaesthetic Management

  • 1-3 % will require intubation. Bag valve-Mask ventilation is very difficult due to severe airway obstruction
  • Rapid sequence induction is used and lidocaine may be given as pretreatment IV to suppress coughing
  • Ketamine is the induction agent of choice as it stimulates catecholamine release which aids bronchodilation
  • The largest tube that can be passed is used as that will allow bronchial toilet.

Discharging patients with asthma can be made safer with a few simple steps

  • On discharge always give a Peak flow metre with instructions how to use it and to seek help if PEFR falling either by escalating treatment e.g self administering steroids and seeking urgent medial help
  • Educate through respiratory nurse. Advise patient and family that patients can deteriorate and if at all concerned then ring 999.
  • Send home on a short course of steroids. Be aware that those who do badly tend to come from more difficult social environments and may be wise to hold on to them longer
  • Happier at sending home earlier those who are sensible and who have someone with them to get help if any problems
  • Give direct and unambiguous advice to return if worsens by 999 if needed. Document it.

COPD vs. Asthma

  • Ensure you have a good understanding of the similarities and the differences between asthma and COPD
  • Both cause airways obstruction and wheezy breathlessness but not all those who smoked have COPD and sometimes it is late onset asthma.
  • COPD is rare under 35 and uncommon in non smokers (but always think ? AAT deficiency)
  • A diurnal variation more seen with asthma and more of a response to therapy is seen
  • Night-time waking with breathlessness and/or wheeze and cough suggests asthma
  • Look for the presence of absence of reversibility
  • Reversibility trial
    • Measure FEV and FVC before and after either 8 weeks inhaled steroid or Prednisolone 30 mg for 2 weeks
    • A > 15% improvement suggests the diagnosis is asthma

Allergic Broncho-pulmonary aspergillosis

Introduction

  • ABPA included here as this is mainly a disease of chronic severe asthmatics
  • Not an infection but hypersensitivity to a ubiquitous fungus.
  • Seen in those with long term asthma or Cystic fibrosis

Aetiology

  • There is an IgE response to the fungus

Clinical

  • Worsening symptoms in known asthmatic
  • Expectorate dark mucous plugs, Malaise, fever

Investigations

  • Precipitating IgG antibodies to Aspergillus species
  • Elevated serum IgE (> 1000 ng/mL)
  • Eosinophil laden mucus plugs found in the airways.
  • CXR/HRCT shows proximal bronchiectasis and transient or fixed pulmonary infiltrates
  • Raised blood eosinophils (> 1 × 109 cell/µ?)
  • Positive responses to Aspergillus on skin testing

Management

  • Steroids (Prednisolone 40-50 mg/day) can suppresses the inflammatory response
  • Removal of mucus plugs is also possible by bronchoscopy
  • More recent work suggests a role for itraconazole

Chronic obstructive airways disease

Introduction

  • Lack of reversibility measured by FEV 1.0 is key to the diagnosis of COPD
  • Almost always a smoker's disease with progressive irreversible airflow limitation
  • Heightened inflammatory response of the lung with progressive lung damage.
  • Distinct pathologies emphysema and chronic bronchitis merge in degrees to form COPD.

Causes

  • Smoking is the main risk factor but only a fraction of smokers develop COPD
  • A genetic susceptibility is important
  • Alpha-1 anti-trypsin (AAT) deficiency
  • Coal workers and Cadmium workers are at increased risk.
  • Smoking marijuana
  • Emphysema
  • Destruction and enlargement of air spaces distal to the terminal bronchiole.
  • Panacinar/Lower lobe destruction - pure AAT deficiency.
  • Centrilobular destruction/upper lobe emphysema is seen in smokers

Chronic bronchitis

  • Defined clinically as a morning productive cough > 3 months per year for 2 consecutive years

Pathophysiology

  • Increased T lymphocytes / neutrophils release proteases (elastases) damaging local normal elastic walls.
  • Damage heightened in those with antiprotease deficiency
  • Smokers have increased protease activity
  • Increased Bronchial mucus secretion with an increase in size and number of bronchial mucus glands.
  • 'Air trapping' leads to V/Q mismatch and hypoxia.
  • Hypoxia and respiratory acidosis induce pulmonary vasoconstriction and eventually cor pulmonale.

Pathology

  • Mucous gland hyperplasia, Impaired cilia function,
  • Squamous metaplasia (columnar cells become squamous)
  • Chronic inflammatory process, Localised fibrosis
  • Alveolar wall destruction - centriacinar and panacinar emphysema
  • Large emphysematous spaces > 1cm are called bullae.

Clinical

  • Chronic cough with sputum production
  • Progressive breathlessness which leads to progressive limitation of mobility
  • Hypoventilating “Blue bloaters” – with cyanosis,right heart failure and retain CO2.
  • Hyperventilating pink puffers who are thin, breathless not retaining CO2
  • Prolonged expiration > 5 seconds
  • Nicotine stained fingers
  • Use of accessory muscles
  • Hyperinflated Barrel chest, Hyperresonance to percussion
  • Shortened cricoid to notch distance of 3 finger breadths or less
  • Loss of cardiac dullness on percussion.
  • Pursed lip breathing
  • Central cyanosis
  • Heart sound loudest in epigastrium as heart pushed more vertically by large emphysematous lungs
  • Raised JVP and peripheral oedema with cor pulmonale

Differentials

  • Asthma, Bronchiectasis
  • Heart failure

Investigations

  • FBC may show polycythaemia especially if continues to smoke
  • CRP/ESR raised if infection
  • CXR can show hyperinflation, flattened diaphragm, bullae, prominent pulmonary vessels and exclude a tumour or consolidation
  • ECG AF, RBBB P pulmonale, RAD.
  • Reduced FEV1 < 80%, FEV/FVC < 70% with < 10% reversibility.
  • Raised FRC (Functional residual capacity) and total lung volume
  • Reduced gas transfer factor (DLCO) with emphysema
  • Serum alpha-1 antitrypsin low in AAT deficiency test in those age < 40 years or with a family history.
  • HRCT can show some of the damage and dilatation of the airways and bullae
  • Functional tests - BODE index assesses BMI, FEV1, dyspnoea and 6 minute walking tests and predicts mortality

Severity FEV1

  • Mild airflow obstruction 50–80% predicted - may have symptoms
  • Moderate airflow obstruction 30–49% predicted - likely to have symptoms - cough, breathless, wheeze, Increased FRC and decreased TLCO
  • Severe airflow obstruction < 30% predicted - hyperinflated lungs, breathless, hypoxic, cor pulmonale

Management

  • Smoking cessation improves prognosis and slows deteriorating FEV.
  • Initially use short acting beta agonists on a PRN basis e.g salbutamol
  • Tiotropium an inhaled long acting anticholinergic improves FEV1 and reduces the frequency of exacerbations
  • Long acting bronchodilators (LABD) e.g salmeterol aid expiration and improve symptoms and exercise tolerance
  • Oral theophylline may be useful but be wary of interactions
  • Inhaled steroids may be added to those with FEV < 50% predicted with more than 2 exacerbations a year
  • Oral steroids used for acute flare ups and then stopped or weaned off slowly
  • Surgery - In a small number lung volume reduction surgery is useful - bullectomy and Lung volume reduction may be done thorascopically.
  • LTOT (Long term oxygen therapy) - Pulse oximetry to identify patients needing LTOT
  • Oxygen concentrators should be used to supply the LTOT at home
  • Assessments usually delayed until 6 weeks post exacerbation
  • Caution as uncontrolled oxygen can lead to drowsiness and CO2 retention
  • Long term oxygen therapy which can prevent pulmonary hypertension if used for 15+ hrs /day
  • Aim to keep SaO2 > 90 % and PaO2 > 8 Kpa.
  • Pulmonary rehabilitation improves mobility, quality of life and reduces Symptoms and hospital admissions
  • Vaccination against influenza and pneumococcus recommended
  • Patients should be supplied with antibiotics and steroids and educated when to take them with exacerbations.
  • Involvement of respiratory nurses to educate and support discharges and follow up can prevent admissions and possibly reduce the severity and frequency of exacerbations.

Acute Exacerbation of COPD

Introduction

  • Make sure you know the indications for NIPPV
  • Not all breathlessness in COPD is due to COPD
  • In selected patients consider pulmonary embolism, heart failure or a small pneumothorax.

Cause of exacerbations

  • Irritants e.g Cigarette smoke, noxious particles and gases e.g SO2, NO2, Ozone.
  • Viral infections - Rhinoviruses, Coronaviruses, Influenza, Parainfluenza, Adenovirus, Respiratory syncytial virus
  • Bacterial/other infections - Haemophilus influenza, Streptococcus pneumonia, Moraxella catarrhalis, Pseudomonas aeruginosa, Chlamydia pneumonia

Additional Symptoms and signs include

  • Increasing breathlessness, expiratory wheeze, malaise, "acopia"
  • Cough which may be productive, Tiredness and exhaustion.
  • Pursed lips breathing, barrel chested individual with the use of accessory muscles
  • New onset cyanosis, worsening peripheral oedema

Investigations

  • FBC - elevated WCC and CRP may suggest infection
  • CXR - Hyper expanded dark lungs, consolidation or patchy shadowing, lung malignancy, exclude Pneumothorax - old films might help to identify Bullae
  • Arterial Blood gases - look for hypoxia and acidosis. A pH < 7.25 is a poor prognostic indicator
  • Elevated HCO3 suggests a chronic compensation to respiratory acidosis

Management

  • Sit patient up and supported and so not having to use energy on posture and to allow use of accessory muscles.
  • Chest physiotherapy can aid expectoration and IV fluids can be useful for those too tired to drink
  • Controlled Oxygen is given usually 24-28% initially to achieve a PO2 of 88-92% and slowly increase to 35% checking ABG each time
  • Venturi mask initially 28% at 4 L/min O2 preferred as this allows accurate amounts of oxygen to be given
  • Repeat ABG 30 minutes after altering FIO2
  • If the PaCO2 is normal then increase target oxygen saturation to 94-98% and repeat ABG after 30 minutes.
  • Bronchodilator therapy - Nebulised Salbutamol 2.5-5 mg 4-6 times per day
  • Nebulised Ipratropium bromide (Atrovent)
  • Nebulizers should be driven by air and not oxygen
  • Prednisolone 30 mg od stat +/- Hydrocortisone 100 mg IV
  • Steroids continued for up to 14 days and then stopped.
  • Augmentin or other antibiotics if infection suspected - purulent sputum, fever, raised CRP, consolidation
  • Fever, Sputum, Elevated WCC or CRP, CXR changes
  • NIV is given if respiratory acidosis pH < 7.35 or PCO2 > 6 Kpa
  • It has been found to reduce the need for intubation and ITU admissions, improve blood gases and reduce the work of breathing and also reduces infective complications and hospital stay
  • However it cannot be used in drowsy uncooperative patients, severe acidosis, unstable haemodynamics
  • Full intubation and ventilation may be required if satisfactory oxygenation not possible with NIV and the patient has some potential for recovery
  • Senior medical staff should discuss with ITU and family and patient if possible
  • There may be an advance directive which should be respected
  • IV Doxapram should be considered and is a respiratory stimulant in the tiring patient. May aid expectoration
  • IV aminophylline is not commonly used these days. It is pro arrhythmic.
Reference : NICE COPD Guidance

Alpha-1 Antitrypsin (AAT) deficiency

Introduction

  • An inherited curable cause of emphysema and cirrhosis
  • In a summary PIMM is good PIZZ is bad

Aetiology

  • Deficiency of Alpha-1-antitrypsin due to a gene mutation on chromosome 14
  • Leads to failure to inhibit neutrophil elastase which causes local tissue damage and leads to panacinar emphysema and possibly cirrhosis depending on genotype.
  • Alpha-1-antitrypsin (AAT) is produced in the liver and is an inhibitor of the proteolytic enzyme elastase
  • Elastase released by neutrophils and causes local damage which is reduced by AAT
  • AAT Enzymes Defined by electrophoresis Medium(M) Slow(S) Very Slow(Z)
  • Normals are PIMM. Homozygotes are PIZZ. Heterozygotes are PIMZ. PiZZ is seen in 1 in 2500 in Europe and is the worstgenotype.

Clinical

  • Progressive cough, wheeze, breathlessness and sputum production
  • Clubbing due to bronchiectasis develops
  • Signs of chronic liver disease
  • Panacinar emphysema, Bronchiectasis, Cirrhosis, Hepatocellular carcinoma

Investigations

  • CXR findings of emphysema
  • AAT Serum level below 50 to 80 mg/dL (11 µmol/L) with a severe deficient genotype
  • Liver biopsy shows PAS positive diastase resistant globules and cirrhosis.

Management

  • Stop smoking and reduce alcohol intake otherwise treat as for emphysema/cirrhosis
  • Infusion of pooled human AAT (alpha-1 antiprotease)

  • Gene therapy is a future possibility
  • Lung and liver transplantation available as therapeutic options as the new liver produces normal AAT – curative
  • However the patient requires a life of immunosuppression.

Non-invasive ventilation

Introduction

  • A form of respiratory support that does nor require sedation and paralysis but can augment respiratory function

Mechanism

  • Recruits more alveoli, improves oxygenation, reduces effort for respiratory muscles, increases sensitivity to increased PaCO2

Indications

  • COPD with Respiratory acidosis pH 7.25-7.35
  • Type II Respiratory failure secondary to chest wall deformity, neuromuscular disease or obstructive sleep apnoea
  • Cardiogenic pulmonary oedema unresponsive to CPAP
  • Weaning from tracheal intubation

Methodology

  • Patients are fitted with a tight fitting mask with a humidifier and BIPAP box
  • Room air or supplemental oxygen may be given
  • It is patient triggered to reduce the work of inspiration
  • The machine kicks in during inspiration to raise inspiratory positive airways pressure to a set level
  • Requires patient to relax and cooperate with the machine
  • Aim for O2 saturations of 85-92%
  • Usually given for up to 24 hours depending on clinical progress, sometimes given for much longer

Settings

  • Recommended initial settings for bi-level pressure support in COPD.
  • Expiratory positive airway pressure (EPAP): 4-5 cm H2O
  • Inspiratory positive airway pressure (IPAP): 12-15 cm H2O and may be increased up to 20 cm in small increments.
  • Triggers Maximum sensitivity Back up rate: 15 breaths/min. Back up I:E ratio: 1:3
  • Repeat ABG 4 hourly and aim for pH > 7.30

Contraindications to NIV

  • Life threatening hypoxaemia - consider urgent intubation and ventilation.
  • pH < 7.25 - consider intubation and ventilation
  • Facial trauma/burns Recent facial upper airway
  • upper gastrointestinal tract surgery
  • Fixed obstruction of the upper airway
  • Inability to protect airway
  • Haemodynamic instability
  • Severe co-morbidity
  • Impaired consciousness/Confusion/agitation
  • Vomiting/Bowel obstruction
  • Copious respiratory secretions
  • Focal consolidation on chest radiograph
  • Untreated pneumothorax

Caveats

  • NIV may be used, despite the presence of these contraindications if is to be the “ceiling” of treatment
  • Some will however be tried on NIV as Intubation and Ventilation not appropriate.

Long term Oxygen therapy

Evidence Level A NICE indications for considering long term oxygen therapy (LTOT)

  • Patients with a PaO2 of less than 7.3kPa when stable
  • PaO2 of 7.3 to 8.0kPa when stable but an additional risk feature such as secondary polycythaemia, nocturnal hypoxaemia, peripheral oedema or pulmonary hypertension
  • Oxygen should be used for at least 15 hours a day as there is no benefit for shorter durations

Evidence level D

  • Severe airflow obstruction with FEV1 of less than 30% of predicted
  • Cyanosis, Polycythaemia, Peripheral oedema, Elevated jugular venous pressure
  • Oxygen saturation less than 92% when breathing air.

Department of Health guidelines for use of long term oxygen in COPD

  • Assess when clinically stable and not during acute episode
  • Smoking cessation and bronchodilator therapy established
  • FEV1 < 1.5 L VC < 2.0 L PO2 < 7.3 KPa PCO2 > 6 Kpa
  • Aim for Oxygen usage for 15 hours per day