Chapter 3 - Respiratory Flashcards
Advantages to drug inhalation?
Dose required is smaller and will rveducye side effectsyvgvvvvvcçg
Types of inhalers?
pMDI e.g. Atrovent, spiriva respimat, Atimos modulite, Neovent
Breath actuated inhalers-Salamol Easi-breathe
Dry powder inhalers - Symbicort turbo, Seebri, Duaklir, Ultibro, spiriva, Incruse, Anoro, easyhaler, Bricanyl turbo
Elderly,children and those with co-ordination difficulties can struggle with pMDI, what can they be changed to?
Breath actuated
Dry powder
*Could stay with pMDI but give a spacer.
Who are spacers useful for?
Poor inhalation technique Children Elderly High dose corticosteroids Nocturnal asthma Candiasis prone
How do spacers help?
Reduce aerosol velocity and impaction of drug particles in oropharynx so more deposited in lungs
How does nebuliser droplet size affect its use?
If 1-5 microns mass median diameter -deposited in airways so use for asthma
1-2 microns mass median diameter results in alveolar deposition, e.g pentamidine isetionate for pneumocystis
Common asthma symptoms?
Coughing,
Wheezing
Chest tightness
SoB
What is complete asthma control defined as?
No daytime symptoms No night time awakening (due to asthma) No attacks No need for rescue medication No activity limitations incl. exercise) Normal lung function -FEV1 / peak flow > 80%
Lifestyle changes to help asthmatics?
Losing weight
Physio exercises
Stopping smoking
Why might you be concerned when a theophylline patients stops smoking whilst on treatment?
Smoking is a hepatic enzyme induced leading to reduced theophylline levels, if a patient stops the level will go up potentially causing theophylline toxicity. This can be delayed due to MR preparations but signs are: Severe vomiting Agitation Restlessness Dilated pupils Tachycardia Hyperglycaemia Haematemesis Convulsions Ventricular and supraventricular tachycardias Hypokalaemia
When would a patient not normally receive a loading dose of IV Aminophylline?
Patient already on Aminophylline or Theophylline.
Why might dose changes be required in the following theophylline patient groups?
Hepatic failure, Viral infection,HF, elderly
Smokers and alcoholics?
Hepatic failure, viral infections, HF and being elderly can effect the metabolism of theophylline in the liver increasing the plasma concentration and potentially causing toxicity by going over the 10 - 20 mg/ L range
Smokers and alcoholics have induced liver enzymes resulting in decreased plasma values and therefore may not achieve the therapeutic values to give adequate bronchodilation, of particular problem in severe acute asthma.
How does administration of the phyllines affect blood sampling ?
If IV sample should be taken 4 - 6 hours after whereas with oral it should be 5 days after starting and 3 after changes (4-6 hours after MR dose)
Why monitor for hypokalaemia on Theophylline?
If plasma potassium goes below normal concentration of 4.5mmol / L than it can give rise to arrhythmias, QT elongation, torsade de points, etc. Hypokalaemia can be potentiated by diuretics (thiazides, loop), corticosteroids, beta agonists, phylline derivatives and hypoxia.
A patient with Hx of sudden cardiac disease is given Hydroxyzine for pruritis, why might you be concerned?
Hydroxyzine is contraindicated in patients with QT Elongation, risk factors for QT elongation including electrolyte imbalance, bradycardia, CVD and FHx of sudden cardiac death
Cautioned in elderly due to increased side effect susceptibility, caution in patients on drugs that lower heart rate or potassium.
Why would you ask a patient with a cough of unknown cause if it’s made worse by anything?
Asthma can be triggered by cold air, exercise, allergens, smoking.
What are the characteristics of an asthma cough?
Worsens at night or in the morning
Wheezing, chest tightness and difficulty breathing present.
A link to atopic disorders such as hay fever and eczema
Pathophysiology - eosinophilic / neutrophilic pathways leading to bronchospasm, excess mucus, mucosal oedema, smooth muscle hypertrophy, increased breathing rate, collagen deposition
How does ipratroprium and other mAch antagonists affect asthma pathophysiology?
Decreased cGMP formation to decrease smooth muscle contraction in the lungs therefore reducing bronchoconstriction and mucous secretion
Why is Omalizumab indicated for prophylaxis of severe allergic asthma?
Omalizumab is a humanized IgG1k monoclonal antibody that binds to IgE in the blood, a characteristic of asthma is IgE binding to FCepsilonR1, then IgE crosslinking and degranulation (tryptase / histamine / PGD2 / LTC4 / heparin release). So reducing this will prevent the problems associated with histamine release
Why target IL5 with Benralizumab and Mepolozumab in eosinophilic asthma?
IL5 is associated with chemotaxis and migration of eosinophils, leading to its survival and migration to the lungs.
Eosinophils release eosinophil peroxidase and major basic protein which causes cell damage structurally, bronchial hyperplasia and adaptive immunity activation.
Use of these will reduce blood eosinophils and lung exacerbations in severe asthma.
