Respiratory Flashcards
Example of B2 agonist
salbutamol (SABA)
salmeterol (LABA)
how do beta agonists work
- stimulates the B2 receptor located on smooth muscle of the bronchial tree, causing it to relax, causing vasodilation
- also causes K+ to move from extracellular to intracellular, decreasing K+ concentration in the blood
when are beta2 agonists used
- asthma
- COPD
- hyperkalaemia
contradictions for b2 agonists
cardiac conditions, arrhythmias
side effects of b2 agonists
tremor, muscle cramps, anxiety, palpitations, arrhythmias, tachycardia
possible interactions of B2 agonists
- beta blockers reduce effectiveness
how to give salbutamol as nebs in asthma
with oxygen
how to give salbutamol as nebs in COPD
with air to prevent CO2 retention
examples of anti-cholinergics / anti-muscarinics
SAMA - ipratropium
LAMA - tiotropium
how do anti-muscarinics work
competitive inhibitor for AcetylCholine on muscarinic receptors, decreasing smooth muscle tone, increasing HR and conductivity and decreasing glandular and tract secretion
when are anti-muscarinics used
COPD - SAMA used to relieve, LAMA used to prevent
Asthma - SAMA added to SABA to relieve or LAMA added to LABA and inhaled corticosteroid to prevent
contraindications for anti-muscarinics
those at risk of glaucoma (due to risk of increased intra-ocular pressure), arrhythmias, urinary retention
side effects of anti-muscarinics
arrhythmias, GI disturbance, resp tract irritation, sinusitis, constipation, cough, dry mouth
possible interactions for anti-muscarinics
drugs with other anti-muscarinic effect e.g., tricyclic anti-depressants
example of inhaled corticosteroids
beclomethasone
how do inhaled corticosteroids work
enter cells and modify gene transcription, down-regulating pro-inflammatory interleukins, cytokines and chemokine and up-regulating anti-inflammatory proteins
- they decrease mucosal inflammation, widen airways and decrease mucus secretion
when are inhaled corticosteroids used
asthma and COPD - used as preventers and to decrease exacerbations
contraindications for inhaled corticosteroids
history of pneumonia and in children be cautious - can cause growth suppression
side effects for inhaled corticosteroids
oral candidiasis, pneumonia risk
example of systemic corticosteroids
prednisolone
how does prednisolone work
- binds to glucocorticoid receptors and up regulates anti-inflammatory genes and down-regulates pro-inflammatory genes
- mineralocorticoid effects by stimulating Na and water retention and K+ secretion in the renal tubule
when is prednisolone used
- allergic and inflammatory disorders
- autoimmune suppression
- cancer to decrease tumour swelling
- HRT in adrenal insufficiency and hypopituitarism
contraindications for prednisolone
infection and children (can cause growth suppression)
side effects of prednisolone
immunosuppression, mood changes (insomnia, psychosis, suicidal thoughts, confusion), muscle weakness, easy bruising, DM, osteoporosis, adrenal atrophy
interactions of prednisolone
NSAIDs increase risk of GI bleed, cytochrome P450 inhibitors decrease efficacy
examples of mucolytics
carbocisteine
how do mucolytics work
decrease sputum viscosity, facilitating expectoration
when are mucolytics used
COPD (decrease eaccerbations), Bronchiectasis (via steam inhalation)
contraindications for mucolytics
peptic ulcers (can disrupt the gastric barrier)
side effects of mucolytics
peptic ulcers, rarely gastric bleed
examples of xanthines
theophylline
how do xanthines work
- competitive non-selective phosphodiesterase inhibitors, which increase intracellular cAMP, inhibiting leukotriene synthesis, thus decreasing inflammation and innate immunity
- non-selective adenosine receptor antagnoist (preventing the blocking of irregular heart signals)
when are xanthines (theophylline) used
asthma and stable COPD as a bronchodilator
when are xanthines contraindicated
cardiac disease (arrhythmias), peptic ulcer disease, hyperthyroidism, hypertension, epilepsy, hypokalaemia risk
side effects of xanthines (theophylline)
arrhythmias, N&V, diarrhoea, gastric irritation, palpitations, tachycardia, headache, insomnia, convulsions
interactions of xanthines (theophylline)
may have additive effects if used with b2 agonists such as increasing chance of hypokalaemia
how does oxygen therapy work
increase pO2, increasing diffusion of oxygen to issues
when do you use oxygen therapy
- pneumothorax
- CO poisoning
- acute hypoxaemia
- chronic hypoxaemia
how does oxygen therapy work in pneumothorax
O2 causes decrease in N2, increasing diffusion of nitrogen out of the body
how does oxygen therapy work in CO poisoning
decreases carboxyhemoglobin half life
contraindications for oxygen therapy
chronic type 2 resp failure (severe COPD) - can result in hypercapnia
side effects of oxygen therapy
discomfort
types of oxygen therapy
- reservoir mask (non-rebreathe)
- venturi mask
- nasal cannula
- simple facemask
- non-invasive ventilation (BiPAP / CPAP)
target O2 levels
94-98%
target O2 levels in someone with chronic type 2 RF
88-92%
when to use a reservoir / non-rebreathe mask
acute settings
- if SpO1 <85%
- continuous supply
when to use a Venturi mask
- oxygen and air blended
- if target is less (in CT2RF)
when to use a nasal cannula
- if possible
- variable O2 conc
when to use a simple facemask
- variable O2 conc
- if nasal cannula cannot be used
when to use NIV
- if CO2 retention and hypoxic
- last resort as difficult to wean off
