Resp 5 Flashcards

Question

What is 'Oxygen saturation'? How is it measured? What is the ideal measurement?

Answer 1

O2 saturation of Hb in arterial blood (SaO2) Measured with a pulse oximeter and expressed as a % Ideally \>95%

Answer 2

Arterial blood obtained (usually from radial artery) Blood is heparinised and put in cold water (prevents clotting) Sample put through a blood gas analyser Normally reads pCO2, pO2 and pH

Answer 3

Low pH Hypoxic Normal CO2 Low Hb saturation (\<95%) High resp rate

Answer 4

**Some alveoli poorly ventilated:** Pulmonary embolism Pneumonia Consolidation Early stages of acute asthma **Most alveoli poorly ventilated:** Pulmonary Oedema Fibrosis * - Fibrosing alveolitis* * - Extrinsic allergic alveolitis* * - Pneumoconiosis* * - Asbestosis*

Answer 5

Breathlessness Exercise intolerance Central cyanosis

Answer 6

Low pH Hypoxia Hypercapnia \<95% Hb saturation High resp rate

Answer 7

**Ineffective respiratory effort:** Poor resp effort * - Resp depression (narcotics)* * - Muscle weakness (upper or lower motor neurone disease)* Chest wall problems * - Scoliosis/Kyphosis* * - Trauma* * - Pneumothorax* Hard to ventilate lungs *- High airway resistance (bronchitis, asthma)* **Emphysema**

Answer 8

**Cause:** Alpha1 - antitrypsin deficiency (genetic or smoking) **Effects:** Increased lung compliance (Barrel chest) Airway obstruction (bronchiole collapse during expiration) V/P mismatch Reduced O2 absorption Type 1 failure initially Progresses to type 2 as CO2 transport impaired

Answer 9

pO2 falls below 8kPa Peripheral chemoreceptors sense this and increase respiratory drive This leads to correction of hypoxia but causes hypocapnia Leads to rise in CSF pH causing an attempted reduction in respiratory drive

Answer 10

Increased ventilation causes hypocapnia Renal correction of acid base balance in blood (decrease in HCO3- in blood corrects pH) Increased ventilation persists due to continued action of peripheral chemoreceptors

Answer 11

pCO2 rises, pO2 falls Central chemoreceptors increase respiratory drive Breathlessness is felt and respiration rate increases This provides some respiratory compensation However poor ventilation (due to disease) prevents full compensation

Answer 12

**CO2 retention:** CSF rise in pCO2 corrected by choroid plexus Central chemoreceptors are reset to higher CO2 level Hypoxia persists Reduction in respiratory drive (which is now driven by peripheral chemoreceptors (hypoxia) **Pulmonary circulation:** Hypoxia causes pulmonary hypertension leads to right heart failure (cor pulmonale) **Hypoxia:** Increased Hb (polycythaemia) 2,3 BPG release **Increased respiratory effort:** Increased work required for breathing Severely disabling

Answer 13

A chronic disorder characterised by: ## Footnote * - Chronic inflammation leading to Airway wall remodelling* * - Reversible, variable airflow reduction* * - Increase in airway response to variety of stimuli (Airway hyper-responsiveness)* * - Susceptibility to infection*

Answer 14

**Asthma:** Increased acellular membrane thickness Damaged epithelium Thickened reticular basement membrane **Smokers or premature lungs:** As in asthma + Loss of alveolar septa

Answer 15

Th2 lymphocytes are activated by macrophages which have absorbed and processed the antigen Th 2 cells release cytokines which attract and activate mast cells and eosinophils also B cells, which produce IgE 2 phase response results **Immediate response phase(0-20 minutes):** Interaction of allergen and specific IgE leads to mast cell degranulation and mediator release (Histamine, tryptase, prostaglandins and leukotriene) This leads to bronchial smooth cell contraction/bronchoconstriction **Late phase response (3-12 hours later):** Complex array of inflammatory cells, mediators and cytokines that causes airway inflammation Eosinophils release leukotriene C4 which causes shedding of epithelial cells

Answer 16

**Cellular:** Neutrophils Eosinophils Mast cells **Soluble mediators:** Cytokines (TNF-a) Leukotrienes Growth factor (involved in repair) **Process:** Chronic inflammation

Answer 17

Mucosal oedema due to vascular leak Thickening of bronchial walls due to infiltration of inflammatory cells Mucus overproduction (thich, tenacious, slow moving, Doesnt come up in dry cough) Smooth muscle contraction Hyperresponsiveness of airways Airway remodelling: * - Hypertrophy and hyperplasia of smooth muscle* * - Hypertrophy of mucus glands* * - Thickening of basement membrane*

Answer 18

Wheeze and other clincal features of asthma Obstructive pattern on spirometry (decreased FEV1/FVC ratio and obstructive flow volume loop) Air trapping increases residual volume

Answer 19

Airway narrowing leads to reduced ventilation Hyperventilation cannot compensate for reduced O2 but can compensate for CO2 retention by increasing breathed out CO2 **Mild to moderate attack:** Reduced pCO2 and pO2 Type 1 resp failure **Severe attacks:** More extensive airway involvement + exhaustion due to hyperventilation leads to further gas exchange impairment and the loss of CO2 compensation Reduced pO2 and Increasing pCO2 Type 2 resp failure Can be life threatening

Answer 20

SM contraction lead to narrowing of airways Flow is greatly impeded even by seemingly small contraction There is also a large increase in the work required to breath E.g. A 20% reduction in airway diameter leads to 60% reduced airflow and greatly increased work in breathing

Answer 21

Muscarinic antagonists (E.g. Ach) Histamine Cold air Arachadonic acid metabolites (Prostaglandins, Leukotrienes)

Answer 22

Where a larger % reduction in FEV1 is seen in response to increasing histamine levels than would be normally expected AHR is a feature of asthma, however many non-asthmatics have AHR

Answer 23

**Airway obstruction in asthma is reversible:** \>15% improvement spontaneously or on administration of bronchodilators or steroids **COPD airway obstruction is not:** \<15% improvement with treatment

Answer 24

**Hereditary** **Sensitisation to airborn allergens:** Air pollution Tobacco smoke (pre/post-natal or direct) Fungal spores (Damp housing) **Hygiene hypothesis:** Excess hygiene in childhood leads to derangement of normal immune development

Answer 25

**Atopic (Type 1 hypersensitivity)** Allergic asthma Viral induced wheeze (Classified as asthma in under 5s) **Non-atopic (not type 1 hypersensitivity associated):** Aspirin sensitive asthma Occupational asthma (Farmers, Bakers, Welders)

Answer 26

Clinical diagnoses only, non standard definitions for type, severity, findings on investigation etc. **Includes 1 or more of these *reccurent* symptoms:** Wheeze Breathlessness Chest tightness Cough Variable airflow obstruction **AHR and airway inflammation assessment**

Answer 27

**Wheeze:** High pitched, expiratory, musical Originates in airways which have been narrowed by compression or obstruction **In asthma:** Variable intensity and tone Bilateral

Answer 28

Often worse at night Exercise induced Dry (wet indicates infection/COPD etc)

Answer 29

Often with exercise During acute exacerbations Assessment might find: * - Tachypnoea* * - Intercostal Recession (negative pressures draw intercostal muscles inward)* * - Tracheal tug (movement of the trachea and thyroid cartilages downwards)* A prolonged expiratory phase is with or without wheeze is a common marker of asthma

Answer 30

**Onset and pattern of symptoms:** Symptoms Disturbance to life Precipitating factors **Past medical history:** Hayfever, eczema Prenatal smoke exposure **Family history:** Asthma, smoking **Occupational history:** Farms, Woods, Coal fires **Non-asthma drug history** **Pets**

Answer 31

**Inspection:** Chest: * - Scars or deformities* * - Hyperexpansion (barrel chest)* General: * - Hayfever* * - Eczema* * - Lethargy* * - Can they talk?* Room: * - Meds* * - Charts* **Percussion:** Hyperresonant **Ascultation:** Polyphonic wheeze

Answer 32

**Common:** Harrison's Sulcus (indrawing of costal cartilages in children **Uncommon:** Sternal (pectus) deformities

Answer 33

**With a peak flow meter:** Check flow meter is at zero, sit the patient upright Hold device horizontal ask the patient to take a deep breath, firmly seal lips around the mouthpiece and exhale as hard as possible

Answer 34

**Usage:** Better used for monitoring as opposed to diagnosis **Limitations:** Wide range of normal values No correction for ethnicity Less reproducible than FEV1 Effort dependent

Answer 35

Stand or sit patient in upright position Incentivise patients that are children to put in maximum effort (visual cues or trained professional) 2-3 tidal breaths are taken with lips around spirometer Deep breath taken to TLC and then blow out as hard as possible Repeat 3 more times to achieve maximum of 5% variaion from largest FVC Can then be repeated post bronchodilator to test obstructive reversibility

Answer 36

May be normal or show lower airway obstruction on a flow/volume graph Normal or reduced FEV1 and FVC do not exclude asthma Reversibility must be checked **Typical profile:** Low PEFR Low FEV1/FVC ratio *Remember normal profile doesn't exclude and to check reversibility*

Answer 37

Checking for exercise induced bronchoconstriction with an exercise stress test and spirometry Spiro is done pre-exercise 6-8 mins of exercise monitoring SaO2 and HR Perfore post-exercise spiro after 1, 5, 10 and 15 minutes Repeat spiro post bronchodilator

Answer 38

Exhaled NO testing (FeNO) is a test of exhaled levels of Nitric oxide, which is a biomarker for chronic inflammation and is found in higher levels with people with chronic inflammation of the airways, such as in asthma **Procedure:** Lungs are emptied as far as possible Inhaled to Vital capacity through device filter Ehale steadily into device

Answer 39

**Limitations:** Not specific to asthma Normal result doesn't exclude asthma **Uses:** In someone judged as intermediate risk of asthma after initial clinical examination can be tested (in conjuction with other tests) to aid diagnoses

Answer 40

Skin prick allergy test Blood IgE levels in response to specific allergens Test for exercise induced asthma Chest X-rays (exclude other disease such as pneumothorax in acute exacerbations)

Answer 41

**Patients:** Correct recognition of symptoms Timely use of medication Appropriate use of health services Personal asthma action plan **Professionals:** Appropriate medication Concordance with treatment plans

Answer 42

Stop smoking Remove wood/laminate flooring from house (Questionable) Cleaning (Questionable) Fresh air Breast feeding Exposure to allergen/triggers Weight loss Diet (Questionable)

Answer 43

**Reliever therapy:** B2 agonists Muscarinic antagonists Theophylline/Aminophylline **Preventer therapy:** Corticsteroids Leukotriene receptor antagonist

Answer 44

Decrease secretion and number of eosinophils Decrease cytokines released from T lymphocytes Decrease mast cell numbers Decrease macrophage numbers and cytokine secretion Decrease epithelial cell cytokine release Decrease mucos secretion from mucus glands Decrease the leak of endothelial cells

Answer 45

Start treatment at step most appropriate to initial severity Acheive early control Maintain control by stepping up or down as necessary

Answer 46

**Mild:** Inhaled short acting B2 agonist as needed **Moderate:** Add inhaled steroid daily May add inhaled long action B2 agonists **Severe:** Consider increasing steroid dose and adding further drugs (E.g. theophylline) Finally add daily steroid tablet

Answer 47

**Mild:** SaO2 \>92% in air HR \<110 RR \<25 Speech normal Minimal wheeze PEFR \>75% predicted **Moderate:** As above however Increased wheeze PEFR 50-75% predicted **Severe:** SaO2 \<92% in air HR \>110 RR \>25 Cant complete sentences No wheeze PEFR 35-50% predicted

Answer 48

SaO2 \<92% in O2 Silent chest, Poor respiratory effort Altered onciousness/hyper-aggressive Exhaustion PEFR \<35% predicted Rising or 'normal' pCO2

Answer 49

*GET HELP* A - Oxygen B- Continuous salbutamol and iptatropium nebs C - IV access (Salbutamol, Mg Sulphate, Aminophylline) Intubate and ventilate Short course of oral prednisilone may also be required Increase through steps as required until symptoms resolve

Resp 5 Flashcards

(73 cards)