Week 207 - OSA and Chest Wall

Question 1

Week 207 - OSA and Chest Wall: Where does control of the respiratory rhythm come from?

Answer 1

Medulla Oblongata

• Ventral respiratory group (mostly expiratory firing)
• Dorsal respiratory group (mostly inspiratory firing)

Question 2

Week 207 - OSA and Chest Wall: What is the group pacemaker hypothesis?

Answer 2

• Membrane properties of individual neurones and connections between neurones, generate rhythmic bursts of firing.

Question 3

Week 207 - OSA and Chest Wall: What is the role o the pontine respiratory group?

Answer 3

Fine tunes the respiratory rhythm.

Question 4

Week 207 - OSA and Chest Wall: What are the four airway and lung reflexes that fine tune respiration?

Answer 4

• Nose + upper airways; irritant receptors > Vagus nerve.
• Stretch receptors > Vagus nerve.
• Irritant receptors > Vagus nerve > Bronchoconstriction.
• J receptors in alveoli - Engorged capillaries / interstitial fluid > Vagus nerve > Dyspnoea.

Question 5

Week 207 - OSA and Chest Wall: What is the main chemical stimulus for breathing when PaO2 and PaCO2 are normal?

Answer 5

Co2

Question 6

Week 207 - OSA and Chest Wall: In what situation can O2 directly stimulate breathing?

Answer 6

At low levels of PO2.

Question 7

Week 207 - OSA and Chest Wall: What is the name of scoring system for assessment of sleep apnoea?

Answer 7

Epworth sleepiness scale.

Question 8

Week 207 - OSA and Chest Wall: What are the ABG results for a person in Type I respiratory failure?

Answer 8

PO2 : Low
PCO2 : Normal (or low)
pH : Normal (or alkalosis)
HCO3 : Normal (or low)

Question 9

Week 207 - OSA and Chest Wall: What are the ABG results for a person in Type 2 respiratory failure?

Answer 9

PO2 : Low
PCO2 : High
pH : Acidosis (or normal)
HCO3 : High (or normal)

Question 10

Week 207 - OSA and Chest Wall: What is the FEV1, FVC and FEV1:FVC in a restrictive lung disease?

Answer 10

• FEV1 and FVC are both reduced since there is a reduced volume.
• The ratio will therefore be normal (or may increase since FVC is reached quickly).

Question 11

Week 207 - OSA and Chest Wall: What are the three types of Acid Maltase deficiency?

Answer 11

• It is an autosomal recessive disease.
• Defect of lysosomal enzyme.
• Causes painless, slow, progress proximal muscle myopathy. (Diaphragm involvement is common, presents with respiratory failure)

Question 12

Week 207 - OSA and Chest Wall: What are the three types of Acid Maltase deficiency? Describe each briefly.

Answer 12

• Infantile - Organomegaly, skeletal muscle involvement, CVS, Resp. failure and usually death <2years.
• Juvenile - limited survival.
• Adult - Best prognosis.

Question 13

Week 207 - OSA and Chest Wall: What is the definition of obstructive sleep apnoea?

Answer 13

Stopping (or slowing) of breathing during sleep due to obstruction of the upper airway.

Question 14

Week 207 - OSA and Chest Wall: What is the incidence of OSA?

Answer 14

2-5% men and 1-2% of women have OSA worthy of treating.

Question 15

Week 207 - OSA and Chest Wall: What is the aetiology of OSA?

Answer 15

• Pharyngeal incompetence brought on by sleep.
• Periods of arousal from sleep to clear airway.
• Markedly fragmented sleep.
• Daytime consequences (Sleepiness)

Question 16

Week 207 - OSA and Chest Wall: What are the risk factors for developing OSA?

Answer 16

• Obesity
• Lower facial shape.
• Tonsils, Hypothyroid, smoking, acromegaly, nasal problems, alcohol, sedatives, menopause, neuromuscular diseases/stroke.

Question 17

Week 207 - OSA and Chest Wall: What is the distribution of male:female in OSA?

Answer 17

M:F, 4:1 > 10:1

Question 18

Week 207 - OSA and Chest Wall: What is the age distribution of OSA?

Answer 18

• Can occur at any age, but increases with age and the peak presentation is 40-60 years.

Question 19

Week 207 - OSA and Chest Wall: What are the daytime symptoms of OSA?

Answer 19

• SLEEPINESS
• Dry mouth
• Morning Headaches
• Poor concentration
• Irritability
• Anxiety/depression
• Loss of libido

Question 20

Week 207 - OSA and Chest Wall: What are the night time symptoms of OSA?

Answer 20

• Snoring
• Choking
• Nocturia
• Apnoeas
• Sweats
• Restless Sleep
• Vivid dreams

Question 21

Week 207 - OSA and Chest Wall: What are the laboratory investigations available for OSA? Give a brief description of each.

Answer 21

• Simple oximetry.
• Embletta - Oximetry, Nasal flow, Snoring, Pulse, Chest movements.
• Visilab - Observation and data obs. (Sleeping position, Activity, sats, pulse)
• PSG - Polysomnography, studies EEG, EOG, EMG, ECG.

Question 22

Week 207 - OSA and Chest Wall: What is the management of OSA?

Answer 22

• Address underlying cause (acromegaly, hypothyroidism)
• Stop evening alcohol and sedatives.
• Stop smoking.
• Lose weight.
• Posture training.

Question 23

Week 207 - OSA and Chest Wall: What are the four functions of the pericardium?

Answer 23

• Stabilisation of the heart within the thoracic cavity, due to its ligamentous attachments.
• Protection.
• Pericardial fluid functions as a lubricant.
• Prevention of excessive dilation of the heart.

Question 24

Week 207 - OSA and Chest Wall: What are the symptoms of reasonably large pericardial effusion?

Answer 24

• Disruption to haemodynamics of heart.
• SOB
• Dysphagia
• Hoarseness
• Hiccups

Question 25

Week 207 - OSA and Chest Wall: What are the signs on an ECG of a pericardial effusion?

Answer 25

Low Voltage. | electrical alternans.

Question 26

Week 207 - OSA and Chest Wall: What are the signs of tamponade?

Answer 26

* Tachycardia * Hypotension * Rales/oedema/ascites * Muffled heartsounds * pulsus pardoxus

Question 27

Week 207 - OSA and Chest Wall: What is the basic outline of the jugular venous wave form?

Answer 27

* a Wave is first, this is due to contraction of the right atrium. * x descent, small descent due to relaxation of the atria. * c Wave, not normally visible. * x descent, during early stage of systole, fall of R.atrial pressure, floor of RA and tricuspid valve drops due to rv contraction. * v Wave, due to continuous filling of right atrium, whilst tricuspid valve is closed. * y descent, reduction in right atrium pressure due to opening of tricuspid valve.

Question 28

Week 207 - OSA and Chest Wall: Describe what is occurring during the a Wave of the JVP.

Answer 28

* First positive presystolic wave. * Dominant wave in JVP. * Due to the contraction of the right atrium. * Precedes S1 but comes after the ECG p wave.

Question 29

Week 207 - OSA and Chest Wall: The c Wave of the JVP is not always present, what does it interrupt and what can it signify?

Answer 29

* Appears as a wave during the x descent. * Transmitted carotid pulsations. * Upward bulge of closed tricuspid valve is isovolumic systole.

Question 30

Week 207 - OSA and Chest Wall: What is the v Wave?

Answer 30

• Due to increased pressure in the right atrium due to continuous filling whilst the tricuspid valve is closed.