Respiratory Flashcards
Paroxysmal and reversible obstruction of the airways
History of recurrent episodes of wheezes, chest tightness, breathlessness, and/or cough, particularly at
night/early morning
Symptoms may be triggered by specific triggers (e.g. pollens, pets, cold air or perfumes)
Symptoms may worsen after taking beta-blockers, aspirin or NSAIDs (BAN) — Paracetamol is safe
Evidence of variable airflow obstruction seen on tests such as peak expiratory flow measurement
Asthma
Bronchospasm (smooth muscle spasm narrowing airways)
Excessive production of secretions (plugging airways)
Acute asthma
Risk Factors for Asthma
A combination of genetic & environmental factors
Personal history of atopy (genetic tendency to develop allergic diseases) such as eczema
Family history of asthma or atopy
Inner city environment
Prematurity and low birth weight
Smoking
Maternal smoking
Presentation of Acute Asthma
Cough
SOB
Wheezes
Chest tightness
Slight tachypnea, tachycardia
Classically, expiratory wheeze is
heard (widespread wheeze)
Mild Attack
o Use of accessory muscles of
respiration
o Inability to complete a sentence
in one breath
o Intercostal retractions
Acute Severe Attack
Silent chest (no wheeze at all)
Exhaustion
Altered consciousness
Cyanosis
Arrythmia
hypotension
Poor respiratory effort
PEF <33% best or predicted
RR >26
Sp02 <92%
Pa02 <8 kPa
Normal PaCO2 (4.6-6 kPa)
Life-threatening Attack
SE of Atenolol
wheezing
SE of Ramipril
cough
Initial diagnostic tool — Reversible obstructive pattern
Pulmonary function tests (SPIROMETRY)
Day-to-day peak flow variability showing diurnal cycle
Treatment monitoring and adjustment
Diagnostic for Asthma
Symptoms of Asthma
Post-dilator improvement of >12% in FEV1/FVC
Unexplained peripheral blood eosinophilia
- Low dose inhaled steroid (preventer) + SABA when needed (reliever)
Asthma in adults
- Very low dose inhaled steroid + SABA when needed (reliever)
Asthma in children
Add LTRA (e.g. Montelukast)
Asthma in adults
> 5 years — LABA or LTRA // <5 years — LTRA
Asthma in children
Increase the dose of inhaled steroids OR add
LABA (Salmeterol)
Asthma in adults
Increase the dose of inhaled steroid
Asthma in children
In severe cases — Short-term oral steroid
Asthma in adults
In severe cases — SR Theophylline
Asthma in children
Immediate treatment [OSTHP]
- Start O, if saturation < 92%, aim for 94-98%
- Salbutamol 5mg (or terbutaline 10mg) nebulized with 02
- IV Hydrocortisone 100mg OR oral prednisolone 40-50 mg
Where diagnosis is uncertain but with
demonstration of airway obstruction [EEV1/FVC « 0.7),
reversibility testing and trial of assessment are suggested
Chest X-ray is not a routine assessment
but it’s useful for
Exclusion
Only benefit for IV hydrocortisone over
oral prednisolone if patient is vomiting or having severe dyspnea where they cannot consume oral medication
True
If immediate TTT is not working, add
ipratropium - MgS04 — IV aminophylline + IV salbutamal (ICU)
In children, tx pf acute exacerbation
OSIPH
IV Salbutamol or IV Aminophylline
Mgs04 comes last
Side effect of B2 agonist
Palpitation and Tachycardia
If life threatening features are present (SIM)
- Give salbutamol nebulizers every 15 minutes, or 10 mg continuously
- Add in ipratropium 0.5mg to nebulizers
- Give single dose of Mg504 (1.2-2g IV) over 20 minutes
If improving within 15-30 minutes (SP)
- Nebulized Salbutamol every 4 hrs
- Prednisolone 40-50 mg PO OD for 5-7 days
» It’s a sign of poorly controlled asthma
» Choice of medication: Short acting beta 2 agonist (used before exercise)
» Review of the regimen including inhaled corticosteroids should be done
Exercise-induced asthma
- Patients who are well controlled on inhaled corticosteroids but complains of exercise being the specific problem,
then consider ADDING either:
- Leukotriene receptor antagonist (LTRA) = Montelukast
- Along-acting beta 2 agonist (LABA) = Salmeterol
- Sodium cromoglicate
- An oral beta 2 agonist
- Theophylline
- This would be taken 2h before an exercise and will prevent symptoms for approximately 12h
» History of smoking and progressive dyspnea
» Evidence of irreversible airflow obstruction on spirometry
- FEV1 < 80% predicted
- FEV1/FVC < 0.7 (Post-dilator)
» All spirometry findings are increased (TLC, RV) except for DLCO & VC
COPD
Presentation of COPD
- Cough + sputum production
- Dyspnea
- low-grade fever (mostly afebrile)
- Wheezes
Investigations of COPD
Raised hematocrit
Chest X-ray is not recommended but if ordered
- Hyperinflated lung fields
- Flattened diaphragm
- Prominent posterior ribs markings (>7 posterior ribs seen)
- Small heart
- May see bullae
Productive cough (TABLESPOON of mucus)
that lasts for three months or more per year
for at least two years
Chronic Bronchitis
is now the preferred term for patients
with airflow obstruction who were
previously diagnosed with chronic bronchitis
or emphysema
COPD
Asthma Vs COPD
Reversibility distinguishes asthma from
COPD
COPD is almost refractory to medication
Almost all COPD patients do smoke or have
smoked in the past
COPD tend to be in old age (>35 years)
» Asthma patients can develop COPD later in life
» Venturi mask doesn’t create +ve pressure
unlike non-invasive ventilation
MAanagement of COPD
- Antibiotics — If sputum is purulent or clinical signs of pneumonia
- Prednisolone 30mg/day for 7-14 days
- Nebulized normal saline — to clear out mucus
- Inhaled or nebulized bronchodilators
- Controlled 02 therapy 24% via Venturi face mask, with oximetry Maintain saturations between 88% and 92%
- |V aminophylline Beneficial if the patient is wheezy and has not improved with nebulizers alone
- Non-invasive ventilation — RR> 30, pH< 7.34, falling Pa02 or rising PaC0O2 despite medical treatment
Invasive mechanical ventilation
Indications
- Failed NIV
- Contraindicated NIV in scenarios such as: respiratory arrest, high aspiration risk or impaired mental status
Complications
Invasive mechanical ventilation
¢ Pneumonia
* Barotrauma
* Failure to wean to spontaneous ventilation
A respiratory stimulant, given IV
Used to drive respiratory rate if >20 breaths/minute
Been replaced by NIV
Doxapram
amount of air in the lungs after maximal inspiration
TLC
amount of air that remains in the lungs after maximal expiration
RV
amount of air that is pushed out of the lungs after maximal inspiration
VC
amount of air pushed out of the lungs after forced maximal expiration
FVC
amount of air pushed out of the lungs in 1sec during maximal expiration
FEV1
FEV1 - decreased
Less than 80% of predicted
Obstructive
FEV1 - decreased
Less than 80% of predicted
Restrictive
FvC N
More than 80% of predicted
Obstructive
FvC - decreased
Less than 80% of predicted
Restrictive
FEV1/FVC decreased
Less than 0.7
Obstructive
FEV1/FVC - N
0.7-0.8
OR
increased
More than 0.8
Restrictive
Obstructive Lung Disease
vs
Restrictive Lung Disease
Long-term oxygen therapy (LTOT)
Prescribed to patients with COPD and severe chronic hypoxemia
7 Once started, it’s likely to be life-long
# Usually given over a minimum of 15h a day
Add-ons to improve breathlessness = Prednisolone or Nebulized normal saline
Possible candidates
- Very severe airflow obstruction — FEV] < 30% predicted
- Polycythemia
- (Cyanosis
- Peripheral swelling
- Raised JVP
- Oxygen saturation 92% or less on room air
Conditions for assessment
® Patient should be stable and >5 weeks have passed since last exacerbation of COPD
® (On a fully optimized treatment for COPD
- 2 sets of ABG are taken 3 weeks apart to ensure the patient is sufficiently hypoxic
Indications
- p02<7.3kPa
- p02 =7.3kPa+ one of the following:
- 2ry polycythemia (raised hematocrit)
- Peripheral edema
- Pulmonary hypertension
Non-invasive ventilation
Indications
- Acidosis (pH <7.35)
- Rising PaCO2
- Falling Pa02
- RR=30
All of these despite medical management (steroids, nebulized bronchodilators & standard 02 therapy) is an
indication of non-invasive ventilation
Risk Factors for Pulmonary Embolism
is suspected with normal X-ray & normal chest examination
Pulmonary embolism
Respiratory alkalosis + Hypoxia =
Pulmonary embolism
Respiratory alkalosis + NO hypoxia =
Panic attack
Symptoms of PE
Dyspnea
Pleuritic chest pain or retrosternal chest pain
Cough and hemoptysis
Signs of PE
- Tachypnea, tachycardia
- Hypoxia, anxiety, restlessness, agitation and impaired consciousness
® Pyrexia - Elevated JVP
- Gallop heart rhythm, a widely split-second heart sound, tricuspid regurgitant murmur
- Pleural rub
- Systemic hypotension and cardiogenic shock
Diagnosis of Pulmonary Embolism
CTPA (CT pulmonary angiogram) — Gold standard
Management of Pulmonary Embolism
Immediate administration of LMWH once PE is suspected (even prior to CTPA)
Results in hyperventilation which causes a respiratory alkalosis
There would be no metabolic compensation as panic attacks resolve rapidly
We would not expect any metabolic compensation as it takes the kidneys days to conserve acid
Pa02 would be normal
Panic attacks
Pulmonary embolism in pregnancy
Chest X-ray should be requested first before deciding whether a V/Q scan or CTPA should be done, in order to
exclude other pulmonary diseases such as pneumonia, pneumothorax or lobar collapse
Abnormal X-ray + clinical suspension of PE = CTPA
Normal X-ray + clinical suspicion of PE = V/Q sean