respiratory unit 2 Flashcards
which drugs should be avoided in asthmatic patients?
Beta-blockers, NSAIDs, aspirin
why is aspirin contraindicated in asthma?
aspirin inhibit cylclo-oxygenase which contributes to the conversion of arachidonic acid to bronchodilatory PGs
when does intrinsic asthma develop and what are symptoms triggered by?
adulthood and triggered by non-allergic factors such as viral infection, irritants and exercise
what causes mucosal oedema?
Platelet activating factor released by macrophages sustains bronchial hyperactivity causing respiratory capillaries to leak plasma leading to oedema
what contributes to airway remodelling?
PAF causing accumulation of eosinophils which release inflammatory mediators causing epithelial damage and hypertrophy and hyperplasia of bronchial smooth muscle
what does the hx of an asthma pt include?
presence of atopy and allergic rhinitis in the close family
what is the pulse rate in acute severe asthma?
> 110 beats/min in adults
what is breathing like in acute severe asthma?
shallow and rapid breathing = >30 breaths/min and low O2 saturation (<92%)
what is the most useful test for abnormalities in airway function?
FEV - inhale deeply as possible and exhale completely into a mouth piece
how much can normal individuals usually exhale?
70% of their total capacity in 1 second
what does a peak flow meter measure?
peak expiratory flow rate (PEF) - maximum flow rate that can be forced during expiration
what diurnal availability is suggestive of asthma?
more than 60L/min (or more than 20%)
when can adrenal suppression occur with inhaled corticosteroids?
belcometasone >1500ncg or budesonide >400ncg in children
how many weeks trial is recommended for LT antagonists?
4-6 week trial then STOP if no improvement
what therapeutic range should theophylline be maintained in?
10-20mg/L
what range can theophylline cause nausea and vomiting in?
common in over 20mg/L but can be seen in as low as 13mg/L
when should an acute asthma attack result in hospital admission?
PEF <50% OR pts has trouble completing sentences in one breath, life threatening features present, pt is too breathless to talk
how would you manage acute asthma?
short course of oral steroid at high dose e.g. prednisolone 40-50mg OD for 7 days, increase B2 agonist dose if deteriorates further then oxygen administration to reach >92%, IV HC if pt cannot take oral medication
what is the main disadvantage of MDIs?
they require good technique
what should pregnant women receiving steroid dose exceeding 7.5mg/day for >2 weeks recieve prior to delivery?
parental HC 100mg 6-8/hr during labour
what is step 3 of the asthma management ladder?
addition of LABA AND assess control of asthma
when would you add 400ncg of an ICs in the asthma managment ladder?
step 2 when SABA is inadaquate
what is the minimum volume that should be nebulised in a nebuliser?
3-4ml
side effects of corticosteroids
oral candidiasis, sore throat, croaky voice