L3 ILP 1: Respiratory Failure Flashcards

1
Q

What is hypoxaemia?

A

Inadequate oxygenation of blood PaO2 < 80mmHg

  • Partial pressure of O2

PaO2 =< 60mmHg = SEVERE hypoxaemia

  • May be acute or chronic
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2
Q

What are 6 pathological basis for hypoxaemia?

A
  1. V/Q mismatch (most common)
  2. Hypoventilation
  3. Diffusion limitation across blood-gas membrane
  4. ↓ FiO2 (eg, high altitude)
  5. Mixed causes
  6. Imbalance between O2 consumption & delivery
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3
Q

What are 5 basis for hypoxaemia?

A
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4
Q

What is hypoxia?

A

O2 delivery to tissues is inadequate to meet metabolic needs

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5
Q

What are 4 causes of hypoxia (results from)?

A
  1. Hypoxaemia- “next stage”
  2. ↓ cardiac output- Heart is not pumped blood (O2) out to the extremities
  3. ↓ Haemoglobin- No vehicle for O2 to bind to
  4. Increase Metabolic rate (eg burns)
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6
Q

What is hypercapnia?

A

PaCO2 >= 50mmHg (normal = 35-45mmHg)

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7
Q

What are 3 major clinical signs of respiratory distress?

A
  1. Respiratory compensation
  2. Increased sympathetic tone
  3. End-organ hypoxia
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8
Q

What are 4 clinical signs about respiratory compensation for respiratory distress?

A
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9
Q

What are 3 clinical signs about increased sympathetic tone for respiratory distress?

A
  1. Increased HR
  2. Increased BP
  3. Sweating (diaphoresis)
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10
Q

What are 5 clinical signs about end-organ hypoxia for respiratory distress?

A
  1. Altered mental status (Brain function)
    1. Confusion
    2. Aggression
    3. ↓awareness & ↓alertness
  2. Fitting
  3. ECG changes
    1. ST depression
    2. Ventricular ectopic beats
  4. Desaturation
    1. Cyanosis (Blueish tinge)
  5. Late signs
    1. Bradycardia
    2. Hypotension
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11
Q

What is respiratory failure?

A

“When the respiratory system is unable to provide adequate gas exchange for metabolic requirements”

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12
Q

What are the 2 types of respiratory failure?

A
  1. PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I
  2. +/- PaCO2 >= 50mmHg (6.7kPa) = Type II
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13
Q

What is type I respiratory failure?

A

PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I

Hypoxaemia without Hypercapnia

(PaO2 <60mmHg; <8kPa)

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14
Q

What is type II respiratory failure?

A

+/- PaCO2 >= 50mmHg (6.7kPa) = Type II

  • Hypercapnia

Hypoxaemia with Hypercapnia

(PaO2 <60mmHg; <8kPa),

(PaCO2 >50mmHg; >6.7kPa)

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15
Q

What are the 3 stages of respiratory failure?

A

Depends on previous ABGs

  1. Acute
  2. Chronic
  3. Acute on chronic
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16
Q

What does the Oxyhaemoglobin Dissociation Curve for respiratory failure look like?

A
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17
Q

What are 10 clinical features of type I respiratory failure?

A

(Hypoxaemia)

Decreased PaO2 ↔PaCO2

  1. Restlessness
  2. Confusion
  3. Aggression
  4. Sweating
  5. Fitting, convulsions
  6. “Plucking”
  7. Increased RR, HR, BP
  8. ECG changes
  9. Blurred vision, tunnel vision
  10. Pallor
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18
Q

What are 7 clinical features of type II respiratory failure?

A

(Hypoxaemia + Hypercapnia)

Decreased PaO2; Increased PaCO2

  1. Flushed skin
  2. Drowsiness
  3. Warm peripheries
  4. Bounding pulse
  5. Headache
  6. Convulsions
  7. Coma
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19
Q

What are the 4 managements of Type I respiratory failure?

A

Improve ventilation

  1. Breathing exercises
  2. NIV = IPPB or CPAP

Mobilise & remove secretions

  1. ACTs
  2. Suction

NB: Will depend on level of co-operation

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20
Q

What are the 3 managements of Type II respiratory failure?

A
  1. Oxygen therapy
  2. NIV = BiPAP OR
  3. Intubation = SIMV
    • Deload lungs, remove CO2
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21
Q

What is the problem, evidence, management and outcome measures of Type I respiratory failure?

A
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22
Q

What is the problem, evidence, management and outcome measures of Type II respiratory failure?

A
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23
Q

What are the 4 mechanisms of pulse oximetry?

A

“SpO2” = % of O2 carried by Haemoglobin (Hb)

  1. Two light emitting diodes
    1. Visible red spectrum
    2. Infrared spectrum
  2. Beams of light pass through tissues to photodetector
  3. Light absorbed by blood and soft tissues
  4. Amount of light absorption depends on degree of oxygenation of Hb within the tissues
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24
Q

What are the 2 values of the pulse oximetry? What are 5 problems that causes the pulse oximetry to be inaccurate?

A
  1. Normal SpO2 = ≥96%
  2. No information on PaCO2
  3. Low perfusion
  4. Hypotension
  5. Movement
  6. Skin pigmentation
  7. Nail polish
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25
Q

What are 4 aims of oxygen therapy?

A
  1. Correct hypoxaemia and therefore aim to decrease tissue hypoxia
  2. Decrease WOB
  3. Decrease myocardial work
  4. Decrease cerebral vasodilation
26
Q

What are 3 delivers of oxygen therapy?

A
  1. Continuous
  2. Intermittent
  3. Nocturnal
  4. Wall – in hospital
  5. O2 concentrator – home
  6. Cylinder – portable
27
Q

What are 4 major dangers of oxygen therapy?

A
  1. Pts with chronic respiratory failure (COPD)
  2. Oxygen toxicity
  3. Depression of ciliary function
  4. Absorption atelectasis
28
Q

What are 2 dangers of oxygen therapy with patients with COPD with oxygen therapy? How do normal people breath VS COPD patients

A
  1. Decreased PaO2 becomes main stimulus to breath (compared to increased PaCO2 levels in people without COPD)
    1. Supplemental O2 may lead to increased PaO2 –> decreased drive to breath
    2. Increased PaCO2 - CO2 narcosis

Normally, increased CO2 levels is what drives people to come up to breath in a pool (not decreased O2 levels)

29
Q

How do normal people breath VS COPD patients?

A
  • Decreased PaO2 becomes main stimulus to breath (compared to increased PaCO2 levels in people without COPD)
  • Normally, increased CO2 levels is what drives people to come up to breath in a pool (not decreased O2 levels)

Normal health: drive from increased CO2 levels

COPD: drive from decreased O2

30
Q

What are 2 dangers of oxygen toxicity with oxygen therapy? What are 2 pulmonary changes?

A

FiO2 0.5 – 0.6 (50-60%) for long periods

Pulmonary changes:

  1. pulmonary oedema
  2. decreased pulmonary compliance

Need to keep oxygen levels as low as possible for all patients

  • While still making sure patient doesn’t go into hypoxia and hypocapnia
31
Q

What are 2 dangers of depression of ciliary function with oxygen therapy?

A
  1. Thickening of secretions
  2. Further secretion retention

Congested airways

32
Q

What are 5 dangers of absorption atelectasis with oxygen therapy?

A
  1. Nitrogen = structural role to hold alveoli open
  2. With ↑O2 in alveoli, nitrogen is moved out (Balancing act between O2 and N2)
    1. structural collapse (atelectasis)
    2. alveoli perfused but not ventilated
    3. V/Q mismatch
33
Q

What are 4 ways to manage the dangers of oxygen therapy?

A
  1. Ensure correct flow and FiO2
  2. Ensure correct fit of device
  3. Monitor improvements / deterioration –> titrate FiO2 accordingly
  4. Minimise side effects
34
Q

What are the 2 types of oxygen therapy devices?

A
  1. Variable: Amount of O2 is varied (uncontrolled, not specific, exact)
    • No setting
  2. Fixed: Amount of O2 is known (specific)
    • Setting for specific amount given
35
Q

What are 3 variable devices for oxygen therapy?

A
36
Q

What are 3 characteristics of variable devices of oxygen therapy?

A
  1. Variable FiO2 as not able to dial device to a set concentration
  2. Lower flow rates
  3. FiO2 vary according to patient’s breathing pattern:
    1. rate
    2. depth
    3. peak inspiratory flow (PIF) demands
37
Q

What are 5 characteristics of variable devices “nasal prongs” of oxygen therapy?

A
  1. Inexpensive
  2. Comfortable, less noticeable, can eat / drink
  3. But, may cause:
    1. pressure areas around mouth & nose
    2. mucosal damage
  4. Flow rate ~= 1- 4 L/min*
  5. FiO2 0.24 - 0.36

*High Flow Nasal Prongs can deliver >6L/min and FiO2 up to100;combined with humidification to prevent drying of airways;

38
Q

What is the L/min VS FiO2 of variable devices “nasal prongs” of oxygen therapy?

A
39
Q

What are 4 characteristics of variable devices “face mask (Inspiron or Hudson)” of oxygen therapy?

A
  1. Inexpensive
  2. Vent holes on sides for release of exhaled gases and to mix with room air
  3. Needs flow rate >= 5 L/min to prevent rebreathing of exhaled gases
  4. FiO2 0.40 - 0.60
40
Q

What is a characteristic of variable devices “tracheostomy” of oxygen therapy?

A

Air should be humidified (since not passing through nose and mouth)

41
Q

What is the L/min VS FiO2 of variable devices “face mask/tracheostomy mask” of oxygen therapy?

A
42
Q

What is a characteristic of variable devices “rebreather masks” of oxygen therapy?

A
43
Q

What 4 characteristics of variable devices “partial rebreather” as oxygen therapy?

A
  1. Exhaled O2 from anatomic dead space is conserved
  2. If insufficient flow –> risk re-breathing CO2
  3. 6-10 L/min
  4. FiO2 =< 0.60
44
Q

What 5 characteristics of variable devices “non-rebreather” as oxygen therapy?

A
  1. One way valve between reservoir bag and mask and over exhalation ports of mask
  2. Prevents exhaled gases re-entering
  3. Prevents room air entering
  4. 10-15 L/min
  5. FiO2 up to 0.80 - 0.90
45
Q

What is the L/min VS FiO2 of variable devices “partial and non-rebreathers” of oxygen therapy?

A
46
Q

What are 3 fixed devices of oxygen therapy?

A
47
Q

What are 3 characteristics of fixed devices of oxygen therapy?

A
  1. Higher flow rates
  2. Deliver fixed FiO2 as total flow usually exceeds patients Peak Inspiratory Flow (PIF) demands
  3. More expensive
  4. FiO2 0.24 – 0.60
48
Q

What are the low and high O2 fixed devices of oxygen therapy?

A
49
Q

What are 8 features that can adversely affect ciliary function?

A
  1. Age
  2. Artificial airways
  3. Dehydration
  4. Inhalation anaesthetic
  5. Lack of sleep
  6. Medications (eg narcotics, sedatives)
  7. Oxygen therapy
  8. Smoking
50
Q

What are 4 ways to prevent adverse effects of ciliary function?

A
  1. Hydration: IV fluids, Oral fluids
  2. Humidification
  3. Nebulisation
  4. Swedish nose (for Tracheostomy)
51
Q

What are 8 indications of humidification?

A
  1. FiO2 >0.35
  2. Thick secretions (Infections)
  3. Consolidation
  4. Major infection
  5. Following surgery
  6. Artificial airway
  7. Diuretic therapy
  8. Dehydrated
52
Q

What are 2 types of humidification?

A
  1. water vapour (Fischer-Paykel)
  2. nebulised particles (Puritan, Aquapak)
53
Q

What is the mechanism of nebulisation?

A
  • Converts solution into fine droplets (aerosol particles), suspended in a stream of gas (based on “baffle” theory)
    • Carried into airways via mouthpiece or mask
    • Driven by wall oxygen or nebulizer pump
  • Used to deliver respiratory medications:
  • Bronchodilators, Corticosteroids; Antibiotics;
  • Antifungals; Mucolytics; Saline (hypertonic)
  • Useful for moistening upper airway of surgical patient (normal saline)
54
Q

What are 4 characteristics of particle size & deposition of nebulisation?

A
  1. 1-10 microns
  2. Pattern of deposition in bronchial tree depends on:
    1. Particle size
    2. Method of inhalation
    3. Degree of airflow obstruction
  3. Large particles - can carry more medication, but do not go far in bronchial tree
  4. Small particles - go further, but do not carry very much medication
55
Q

What are large participles in particle size & deposition of nebulisation?

A

can carry more medication, but do not go far in bronchial tree

56
Q

What are small participles in particle size & deposition of nebulisation?

A

go further, but do not carry very much medication

57
Q

What are the 5 characteristics of the application of nebulisation?

A
  1. Need flow rate 6-8L/min to nebulize
    • Care with patient with hypoxic drive (use medical air instead of O2)
    • <6L/min will not be sufficient to force the air faster enough past the liquid to create the droplets to be inspired
  2. Upright sitting
  3. Slow deep breaths –> laminar flow
  4. Interspersed with TV (prevent hyperventilation)
  5. Mouth breathing
58
Q

What are the 3 characteristics of the mechanism of aerosol therapy?

A

Suspension of fine liquid or solid particles in air

  1. Topical deposition of drug (in lungs)  smaller dose, faster acting, less side-effects (minimal systemic absorption)
  2. Pattern of deposition according to size of particles (see earlier)
  3. –> Gravitational sedimentation = time dependent & enhanced by breath hold
  4. Note: as little as 10% of drug actually reaches lungs (thus, optimize technique)
59
Q

What is aerosol therapy?

A

Suspension of fine liquid or solid particles in air

60
Q

What are 2 devices as inhalers of aerosol therapy?

A
  1. Metered dose inhaler
  2. Turbuhaler
61
Q

What are 4 deliveries as inhalers of aerosol therapy?

A
  1. Bronchodilators, inhaled corticosteroids, anticholinergics –> Spacer device (↑ deposition of drug in lungs instead of oropharynx by approx 15%)
  2. Choice of device: must consider patient age, coordination, dexterity, severity, preference
  3. Oral candidiasis: ↓ by rinsing mouth following inhalation of steriods; use space device
  4. Turbuhaler is breath-actuated (releases drug on inspiration); Suitable for people who are unable to coordinate MDI
62
Q

What are 7 roles of the physiotherapist in respiratory failure?

A
  1. Recognize signs of respiratory failure (Type I vs Type II)
  2. Select appropriate management for people with respiratory distress, and respiratory failure
  3. O2 therapy is a drug - must be treated accordingly, prescribed by medical practitioner
  4. Be aware of potential complications / side-effects of O2 therapy
  5. Ensure correct application of O2 therapy (delivery device, flow rate, concentration)
  6. Select humidification where appropriate
  7. Observe & review technique of application of nebuliser and aerosol therapies