Respiratory COMPLETE Flashcards
Respiratory failure, COPD, Asthma, Pneumonia, DVT/PE inc prevention and anticoag, Pneumothorax, Lung cancer, Pleural effusion, OSAS (132 cards)
Give 5 broad causes of Type I Respiratory Failure.
VQ mismatch e.g. PE, atelectasis
Shunt e.g. patent foramen ovale, atrial septal defects
Low inspired oxygen concentration e.g. high altitude
Alveolar hypoventilation e.g. neuromuscular disorders, chest wall deformities, interstitial lung disease
Altered gas diffusion e.g. pneumonia, ARDS, pulmonary fibrosis
Give 4 broad causes of Type II Respiratory Failure.
Reduced breathing effort; sedation, brainstem disorders, obesity, drugs
Neuromuscular diseases; GBS, MND, spinal cord lesions, MG
Thoracic wall abnormalities e.g. kyphoscoliosis
Increased airway resistance e.g. asthma, COPD, pneumonia, lung fibrosis
Explain the differences between CPAP and NIV (BiPAP).
NIV / BiPAP; creates inspiratory and expiratory positive airway pressure, leading to air moving via a pressure gradient. Facilitates CO2 clearance, airway opening and reduces work of breathing. CO2 retention and COPD very useful. High expiratory positive airway pressure also reduces preload and decreases stroke volume
CPAP; continuous positive airway pressure through all phases of ventilation, facilitating oxygenation by stenting open airways. Congestive HF and OSA very useful. Increases intrathoracic pressure and therefore reduces preload. Care should be taken in patients with low BP.
Give the 3 principles of treating respiratory failure.
- Ensuring adequate oxygenation
- Treating the underlying cause of respiratory failure
- Providing supportive care e.g. hydration, nutrition, electrolyte imbalances
** Be aware in type 2 failure that oxygen must be very carefully controlled, as some patients are at risk of CO2 retention.
Give 3 modes of assisted ventilation, and also give 5 mechanisms of damage that assisted ventilation can cause.
HFNO; heated and humidified, through a NC, up 60L/min. Generates PEEP, reducing work of breathing. Cannot be used if reduced respiratory drive.
NIV / BiPAP
CPAP
Oxygen toxicity
Volutrauma / overstretching
Barotrauma / pressure overload
Biotrauma / shear forces
Cardiac overstimulation
Describe the oxygen / co2 concentrations in I and II respiratory failure.
Type I - low oxygen, low / normal CO2. Primary cause is VQ mismatch
Type II - hypoxia + raised CO2.
Give some differential diagnoses for asthma.
COPD
Upper airway obstruction e.g. tumour, laryngeal oedema
Foreign body aspiration
LV failure
Recurrent pulmonary emboli
Eosinophilic pneumonia
Give 5 different types of investigation commonly used when asthma is suspected, and outline the results that would point towards a diagnosis of asthma.
First line: FeNO (or eosinophil count). FeNO ADULTS >50ppb is diagnostic, >35ppb 5-16yrs diagnostic.
Bronchodilator reversibility testing with spirometry:
>12% increase and 200ml or more from pre-bronchodilator measurement OR >10% of predicted normal FEV1.
PEF variability; diagnose asthma if PEF variability >20%, measuring BD for 2 weeks.
If asthma is not confirmed by eosinophil count, FeNO, BDR or PEF variability, refer for:
Bronchial challenge testing (histamine / methacholine)
Give 4 classic symptoms of asthma and 2 clinical signs.
Wheeze
Dry cough worse at night
SOB
Chest tightness
Widespread polyphonic expiratory wheeze
Reduced PEFR
Outline some risk factors for asthma, not including personal / FHx of atopy.
Antenatal; maternal smoking, RSV infection
Low birth weight
Not breastfed
High exposure to allergens e.g. dust mites
Air pollution
What chemical is the culprit for the most common cause of occupational asthma?
Isocyanates - spray painting and foam moulding using adhesives.
Investigation of asthma in children is fairly similar to adults, but some steps are slightly different. Outline these differences.
In adults, eosinophil count is taken first line alongside FeNO, but this is NOT done in children.
Bronchial challenge testing is not considered as soon as in adults (after FeNO, BDR, PEF), but the next line is skin prick testing to house dust mite or measuring total IgE and blood eosinophil count.
Diagnosis of asthma can be made from these two if there is evidence of sensitisation OR a raised total IgE and eosinophil count is >0.5 x 10^9/L
When asthma is uncontrolled, it’s important to consider reasons for this. What could some reasons be?
Environmental e.g. air pollution, dust exposure
Poor adherence to medication
Smoking
Inhaler technique is poor
Alternative Dx or comorbidities
Measure FeNO if uncontrolled, and if high could indicate poor compliance with medication or need for higher ICS dose.
After starting medications for asthma, when should the patient be reviewed?
8-12 weeks later
What type of drug is formoterol?
Fast-acting long acting beta2 agonist.
Acts on airway to relax airway smooth muscle.
What is the discharge criteria following an acute asthma attack (3).
On discharge medications and stable for 12-24 hours.
Checked and recorded inhaler technique.
PEFR >75%.
Discuss management of an acute asthma attack in an adult, including timescale of escalation of treatment.
- Oxygenation if hypoxic.
- High dose inhaled SABA; normally a pMDI. Oxygen driven nebulised is preferred in life threatening.
- Oral prednisolone 40mg / 5 days. Continue normal ICS during this period.
- Ipratropium Bromide
- IV mag sulf
?Aminophylline
?Intubation and ventilation
What is usually seen on an ABG in a patient intially presenting with an acute exacerbation of asthma?
Respiratory alkalosis, as tachypnoea initially causes a drop in CO2.
Normal CO2 is a bad sign, of exhaustion.
Respiratory acidosis due to high CO2 is very bad.
When should follow up of a mild acute exacerbation of asthma occur, and how should it be managed?
Within 48 hours.
SABA via spacer.
Quadrupled dose of ICS for up to 2 weeks.
Consider oral steroids.
?Abx if convincing infection
What are the potential side effects of salbutamol therapy?
Hypokalaemia (K+ is absorbed from blood into cells, must be monitored)
Tachycardia
Lactic acidosis
What is the most common type of lung cancer overall, and the most common type among non-smokers?
Squamous Cell (nsclc)
Adenocarcinoma more common in non-smokers.
Which type of lung cancer arises from central airways, grows quickly and spreads early?
Small cell lung cancer
Describe the paraneoplastic features seen in squamous cell lung cancer.
PTHrP secretion causing hypercalcaemia.
Clubbing
HPOA - hypertrophic pulmonary osteoarthropathy
Ectopic TSH causing hyperthyroidism
What is Lambert-Eaton myasthenic syndrome, and which 3 types of cancer can it be associated with?
Mainly SCLC, but breast and ovarian too.
Antibody directed against calcium channel in PNS; causes limb girdle weakness, repeated muscle contractions, hyporeflexia, autonomic sx including dry mouth, impotence and micturation difficulty.