Session 5 - Hypoxia, Chemical Control Of Breathing + LRTI Flashcards

1
Q

Define Hypoxia

A

A fall in alveolar, thus arterial pO2

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2
Q

Define Hypoventilation

A

When ventilation falls with no change in metabolism

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3
Q

What effects does Hyperventilation have on pCO2 and pH

A
  • pCO2 decreases

- pH rises

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4
Q

How is a respiratory acidosis compensated for?

A

Kidneys reduce excretion of Hydrogen Carbonate, hence more is in the plasma, more hydrogen ions are buffered and pH rises to normal levels

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5
Q

Why can a severe Metabolic Alkalosis not be fully compensated for?

A

To compensate the lungs reduce ventilation rate. However RR must be kept at a minimum level to ensure that hypoxia doesn’t occur.

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6
Q

Where are the peripheral chemoreceptors located?

A

Carotid and Aortic bodies

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7
Q

What does stimulation of central chemoreceptors cause?

A
  • Increase in tidal volume and RR
  • More blood directed to brain and kidneys
  • Increased pumping of heart
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8
Q

Which out of central or peripheral chemoreceptors detect more acute changes in gas concentrations?

A

Central

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9
Q

By which cells is the CSF’s Hydrogen carbonate concentration controlled by?

A

Choroid Plexus Cells

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10
Q

How do Type 1 and 2 respiratory failure differ?

A

Type 1 - Normal or low pCO2

Type 2 - Raised pCO2

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11
Q

How is living at altitude a risk factor for respiratory failure?

A

Lower pO2 of inspired air means hypoxia can result

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12
Q

Which type of respiratory failure is Hypoventilation linked with?

A

Type 2 only

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13
Q

Which type of respiratory failure is diffusion impairment always associated with and why?

A

Type 1

Because carbon dioxide diffuses much more easily than oxygen it is rarely effected by diffusion difficulties

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14
Q

Give some examples of when there may be a ventilation perfusion mismatch.

A
  • Lobar Pneumonia

- Pulmonary embolism

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15
Q

Give some of the most common normal flora in the respiratory tract.

A
  • Viridans Strep
  • Neisseria Strep
  • Anaerobes
  • Candida Strep
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16
Q

What are some of the natural defences our respiratory tract has against infections?

A
  • Cough and sneeze reflex
  • Muco-ciliary clearance mechanisms (cilia and nasal hairs)
  • Resp mucosal immune system (macrophages, IgA, IgG)
17
Q

Give the names of some of the viruses which cause the most common URT infections

A
  • Rhinovirus
  • Coronavirus
  • Influenza / Parainfluenza
18
Q

Define Pneumonia

A

A general term donating inflammation of the gas-exchanging regions of the lung, usually due to infection

19
Q

What is the difference between bronchiole and Lobar Pneumonia?

A

Lobar pneumonia is localised to a particular lobe of the lungs whereas bronchiole starts in a bronchiole and spreads to all regions that the bronchiole branches into

20
Q

What are the most common organisms which cause community acquired pneumonias?

A
  • Strep pneumoniae
  • Haemophilus influenza
  • Klebisiella pneumoniae
21
Q

Name some organisms which commonly cause hospital acquired pneumonias.

A
  • Staph aureus
  • MRSA
  • Pseodomonas
22
Q

What are some of the most common symptoms of pneumonia?

A
  • fever, chills, sweats, cough
  • sputum (clear, rusty or heavily stained with blood)
  • Dyspnoea, pleuritic chest pain, malaise, vomiting
  • diarrhoea, headache, myalgia
23
Q

What are the four criteria that make up the CURB 65 score and what are there values which would class them as a positive result for pneumonia?

A
  • C - New mental confusion
  • U - Urea >7mmol/L
  • R - RR >30 per minute
  • B - BP systolic < 90 or diastolic <60mmHg
    If have two or more of above then this is an indication for hospital treatment
24
Q

What samples may be taken for investigations of pneumonias?

A
  • Sputum
  • Nose + throat swabs
  • Endotracheal aspirates
  • Open lung biopsy
  • Blood Culture
  • Urine
25
Q

What microbiological investigation may be undertaken to try and confirm or rule out pneumonia?

A
  • Macroscopic investigation of sputum (colour)
  • G - staining, acid fast
  • Culture
  • PCR
  • Antigen and Antibody detection
26
Q

How may pneumonias be managed in general?

A
  • Fluids; oral or IV if severe
  • Anti-pyretic drugs
  • Analgesics
  • Oxygen - if cyanosed
  • Antiobtiotics
27
Q

What is the usual antibiotic treatment for community acquired pneumonias?

A

Target is usually pneumococcus, which is sensitive to Penicillin or related antibiotics

28
Q

What is the usual antibiotic treatment for hospital acquired pneumonias?

A

Usually G -ve so IV Co-Amoxiclav is used

29
Q

What are the major complications of a pneumonias?

A
  • Lung abscess
  • Bronchiectasis
  • Empyema
30
Q

How can we prevent pneumonias from occurring?

A
  • Flu vaccine
  • Pneumococcal vaccine
  • Chemoprophylaxis: Oral penicillin to patients with high risk of LRTI