Lecture 16 - Symptomatology In COPD Flashcards
1
Q
COPD definition
A
- chronic - never get back to normal lung function again
- obstructive: airflow obsructed, FEV1/FVC decreased, expiratory flow rates decreased
- Pulmonary: not just an airway dysease, lung parenchyma also affected
2
Q
COPD caused
A
- smoking main cause
- occupational exposure
- pollution
- infections
3
Q
Why should we care about COPD
A
- common and under-diagnosed
- high-mortality: 4th cause of death in men, 6th in females
- substantial morbidity: 25% retire prematuraly, 3rd leading cause of burden of dieases, significant cost to health system
4
Q
Mortality and morbidity of COPD
A
- premature mortality by 7 years
- Co-morbidities: depression/anxiety, chest infection, right heart failure, osteoporosis, pneumothorax
5
Q
Inflammation in COPD
A
- Small airway disase: airway inflammation and remodelling
- Parenchymal destruction: loss of alveolar attachments, decrease of elastic recoil - airflow limitation
- the two coexist
6
Q
Symptoms of COPD
A
- SOB/ dyspnoea. On exertion initially, at rest in end-stage disease
- chronic cough +/ sputum production
- wheeze
- ankle oedema
- weight loss
- anorexia
7
Q
Assessment and severity
A
- can have severe airflow limitation
- can have severe SOB symptoms
- don’t have to have both
- mMRC dypnoea scale
- CAT scale
8
Q
Dyspnoea
A
- symptom, not a sign
- term used to characterize a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity
- the experience derives from interactions among multiple physiological, psychological, social and environmental factors, and may induce secondary physiological and behavioral response
9
Q
What is required to allow exercise without breathlessness
A
- air must go in and out
- blood must circulate
- air and blood must meet
- oxygen has to be available to muscle
- muscle must be strong/effective
- load must not be excessive
- response to exercise has to be appropriate
10
Q
Normal response to exercise
A
- need to increase ventilation to maintain O2 and CO2 levels and do this while also reducing work of breathing so that more of cardiac output can be used for muscles and sensation of breathlessness is minimised
11
Q
Limits to exercise in normals
A
- maximal cardiac output is the main limit: max heart rate age related, max stroke volume is trainable
- peripheral muscle oxygen utilisation is trainable
- lungs are pretty good
12
Q
Problem in COPD
A
- usually when you start exercising, you increase your inspiratory capacity to increase tidal volume
- in COPD, they try to increas their tidal volume but cant breathe all the air out, so cant increase their inspiratory capacity
- dyspnoea is inversely proportional to inspiratory capacity
- IC goes down and down over time in COPD
13
Q
Physiological limitations to exercise in COPD
A
- lungs take longer to empty - it is incomplete before you need to take next breath
- end-expiratory lung volume is above FRC
- further increase in end expiratory lung volume when there is a need to icnrease in ventilation
14
Q
Other consequences of dynamic hyperinflation
A
- increased work of breathing: breathing at suboptimal part of the PV curve
- inspiratory threshold load - lungs not empty at start of inspiration so inspiratory muscles have to overcome combined inward recoil of chest wall and lungs before inspiratory flow starts
- altered length-tension of inspiratory muscles: shorter operating length means limited capacity. Use more oxygen for same/less result
15
Q
Other limits
A
- peripheral muscle weakness/wasting
- cardiovascular de-conditioning
- pulmonary hypertension
- Hypoxia
- Anemia
- Anxiety: hyperventilation
