L3 ILP 1: Respiratory Failure Flashcards
What is hypoxaemia?
Inadequate oxygenation of blood PaO2 < 80mmHg
- Partial pressure of O2
PaO2 =< 60mmHg = SEVERE hypoxaemia
- May be acute or chronic
What are 6 pathological basis for hypoxaemia?
- V/Q mismatch (most common)
- Hypoventilation
- Diffusion limitation across blood-gas membrane
- ↓ FiO2 (eg, high altitude)
- Mixed causes
- Imbalance between O2 consumption & delivery
What are 5 basis for hypoxaemia?

What is hypoxia?
O2 delivery to tissues is inadequate to meet metabolic needs
What are 4 causes of hypoxia (results from)?
- Hypoxaemia- “next stage”
- ↓ cardiac output- Heart is not pumped blood (O2) out to the extremities
- ↓ Haemoglobin- No vehicle for O2 to bind to
- Increase Metabolic rate (eg burns)
What is hypercapnia?
PaCO2 >= 50mmHg (normal = 35-45mmHg)

What are 3 major clinical signs of respiratory distress?
- Respiratory compensation
- Increased sympathetic tone
- End-organ hypoxia

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

What are 3 clinical signs about increased sympathetic tone for respiratory distress?
- Increased HR
- Increased BP
- Sweating (diaphoresis)
What are 5 clinical signs about end-organ hypoxia for respiratory distress?
- Altered mental status (Brain function)
- Confusion
- Aggression
- ↓awareness & ↓alertness
- Fitting
- ECG changes
- ST depression
- Ventricular ectopic beats
- Desaturation
- Cyanosis (Blueish tinge)
- Late signs
- Bradycardia
- Hypotension

What is respiratory failure?
“When the respiratory system is unable to provide adequate gas exchange for metabolic requirements”
What are the 2 types of respiratory failure?
- PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I
- +/- PaCO2 >= 50mmHg (6.7kPa) = Type II
What is type I respiratory failure?
PaO2 =< 60mmHg (8kPa) [ie, severe hypoxaemia] = Type I
Hypoxaemia without Hypercapnia
(PaO2 <60mmHg; <8kPa)
What is type II respiratory failure?
+/- PaCO2 >= 50mmHg (6.7kPa) = Type II
- Hypercapnia
Hypoxaemia with Hypercapnia
(PaO2 <60mmHg; <8kPa),
(PaCO2 >50mmHg; >6.7kPa)
What are the 3 stages of respiratory failure?
Depends on previous ABGs
- Acute
- Chronic
- Acute on chronic
What does the Oxyhaemoglobin Dissociation Curve for respiratory failure look like?

What are 10 clinical features of type I respiratory failure?
(Hypoxaemia)
Decreased PaO2 ↔PaCO2
- Restlessness
- Confusion
- Aggression
- Sweating
- Fitting, convulsions
- “Plucking”
- Increased RR, HR, BP
- ECG changes
- Blurred vision, tunnel vision
- Pallor
What are 7 clinical features of type II respiratory failure?
(Hypoxaemia + Hypercapnia)
Decreased PaO2; Increased PaCO2
- Flushed skin
- Drowsiness
- Warm peripheries
- Bounding pulse
- Headache
- Convulsions
- Coma
What are the 4 managements of Type I respiratory failure?
Improve ventilation
- Breathing exercises
- NIV = IPPB or CPAP
Mobilise & remove secretions
- ACTs
- Suction
NB: Will depend on level of co-operation
What are the 3 managements of Type II respiratory failure?
- Oxygen therapy
- NIV = BiPAP OR
- Intubation = SIMV
- Deload lungs, remove CO2
What is the problem, evidence, management and outcome measures of Type I respiratory failure?

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

What are the 4 mechanisms of pulse oximetry?
“SpO2” = % of O2 carried by Haemoglobin (Hb)
- Two light emitting diodes
- Visible red spectrum
- Infrared spectrum
- Beams of light pass through tissues to photodetector
- Light absorbed by blood and soft tissues
- Amount of light absorption depends on degree of oxygenation of Hb within the tissues

What are the 2 values of the pulse oximetry? What are 5 problems that causes the pulse oximetry to be inaccurate?
- Normal SpO2 = ≥96%
- No information on PaCO2
- Low perfusion
- Hypotension
- Movement
- Skin pigmentation
- Nail polish
What are 4 aims of oxygen therapy?
- Correct hypoxaemia and therefore aim to decrease tissue hypoxia
- Decrease WOB
- Decrease myocardial work
- Decrease cerebral vasodilation
What are 3 delivers of oxygen therapy?
- Continuous
- Intermittent
- Nocturnal
- Wall – in hospital
- O2 concentrator – home
- Cylinder – portable
What are 4 major dangers of oxygen therapy?
- Pts with chronic respiratory failure (COPD)
- Oxygen toxicity
- Depression of ciliary function
- Absorption atelectasis
What are 2 dangers of oxygen therapy with patients with COPD with oxygen therapy? How do normal people breath VS COPD patients
- Decreased PaO2 becomes main stimulus to breath (compared to increased PaCO2 levels in people without COPD)
- Supplemental O2 may lead to increased PaO2 –> decreased drive to breath
- Increased PaCO2 - CO2 narcosis
Normally, increased CO2 levels is what drives people to come up to breath in a pool (not decreased O2 levels)
How do normal people breath VS COPD patients?
- 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
What are 2 dangers of oxygen toxicity with oxygen therapy? What are 2 pulmonary changes?
FiO2 0.5 – 0.6 (50-60%) for long periods
Pulmonary changes:
- pulmonary oedema
- 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
What are 2 dangers of depression of ciliary function with oxygen therapy?
- Thickening of secretions
- Further secretion retention
Congested airways

What are 5 dangers of absorption atelectasis with oxygen therapy?
- Nitrogen = structural role to hold alveoli open
- With ↑O2 in alveoli, nitrogen is moved out (Balancing act between O2 and N2)
- structural collapse (atelectasis)
- alveoli perfused but not ventilated
- V/Q mismatch

What are 4 ways to manage the dangers of oxygen therapy?
- Ensure correct flow and FiO2
- Ensure correct fit of device
- Monitor improvements / deterioration –> titrate FiO2 accordingly
- Minimise side effects
What are the 2 types of oxygen therapy devices?
- Variable: Amount of O2 is varied (uncontrolled, not specific, exact)
- No setting
- Fixed: Amount of O2 is known (specific)
- Setting for specific amount given

What are 3 variable devices for oxygen therapy?

What are 3 characteristics of variable devices of oxygen therapy?
- Variable FiO2 as not able to dial device to a set concentration
- Lower flow rates
- FiO2 vary according to patient’s breathing pattern:
- rate
- depth
- peak inspiratory flow (PIF) demands
What are 5 characteristics of variable devices “nasal prongs” of oxygen therapy?
- Inexpensive
- Comfortable, less noticeable, can eat / drink
- But, may cause:
- pressure areas around mouth & nose
- mucosal damage
- Flow rate ~= 1- 4 L/min*
- 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;

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

What are 4 characteristics of variable devices “face mask (Inspiron or Hudson)” of oxygen therapy?
- Inexpensive
- Vent holes on sides for release of exhaled gases and to mix with room air
- Needs flow rate >= 5 L/min to prevent rebreathing of exhaled gases
- FiO2 0.40 - 0.60

What is a characteristic of variable devices “tracheostomy” of oxygen therapy?
Air should be humidified (since not passing through nose and mouth)

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

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

What 4 characteristics of variable devices “partial rebreather” as oxygen therapy?
- Exhaled O2 from anatomic dead space is conserved
- If insufficient flow –> risk re-breathing CO2
- 6-10 L/min
- FiO2 =< 0.60

What 5 characteristics of variable devices “non-rebreather” as oxygen therapy?
- One way valve between reservoir bag and mask and over exhalation ports of mask
- Prevents exhaled gases re-entering
- Prevents room air entering
- 10-15 L/min
- FiO2 up to 0.80 - 0.90
What is the L/min VS FiO2 of variable devices “partial and non-rebreathers” of oxygen therapy?

What are 3 fixed devices of oxygen therapy?

What are 3 characteristics of fixed devices of oxygen therapy?
- Higher flow rates
- Deliver fixed FiO2 as total flow usually exceeds patients Peak Inspiratory Flow (PIF) demands
- More expensive
- FiO2 0.24 – 0.60
What are the low and high O2 fixed devices of oxygen therapy?

What are 8 features that can adversely affect ciliary function?
- Age
- Artificial airways
- Dehydration
- Inhalation anaesthetic
- Lack of sleep
- Medications (eg narcotics, sedatives)
- Oxygen therapy
- Smoking
What are 4 ways to prevent adverse effects of ciliary function?
- Hydration: IV fluids, Oral fluids
- Humidification
- Nebulisation
- Swedish nose (for Tracheostomy)

What are 8 indications of humidification?
- FiO2 >0.35
- Thick secretions (Infections)
- Consolidation
- Major infection
- Following surgery
- Artificial airway
- Diuretic therapy
- Dehydrated

What are 2 types of humidification?
- water vapour (Fischer-Paykel)
- nebulised particles (Puritan, Aquapak)
What is the mechanism of nebulisation?
- 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)

What are 4 characteristics of particle size & deposition of nebulisation?
- 1-10 microns
- Pattern of deposition in bronchial tree depends on:
- Particle size
- Method of inhalation
- Degree of airflow obstruction
- Large particles - can carry more medication, but do not go far in bronchial tree
- Small particles - go further, but do not carry very much medication

What are large participles in particle size & deposition of nebulisation?
can carry more medication, but do not go far in bronchial tree
What are small participles in particle size & deposition of nebulisation?
go further, but do not carry very much medication
What are the 5 characteristics of the application of nebulisation?
- 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
- Upright sitting
- Slow deep breaths –> laminar flow
- Interspersed with TV (prevent hyperventilation)
- Mouth breathing
What are the 3 characteristics of the mechanism of aerosol therapy?
Suspension of fine liquid or solid particles in air
- Topical deposition of drug (in lungs) smaller dose, faster acting, less side-effects (minimal systemic absorption)
- Pattern of deposition according to size of particles (see earlier)
- –> Gravitational sedimentation = time dependent & enhanced by breath hold
- Note: as little as 10% of drug actually reaches lungs (thus, optimize technique)
What is aerosol therapy?
Suspension of fine liquid or solid particles in air
What are 2 devices as inhalers of aerosol therapy?
- Metered dose inhaler
- Turbuhaler
What are 4 deliveries as inhalers of aerosol therapy?
- Bronchodilators, inhaled corticosteroids, anticholinergics –> Spacer device (↑ deposition of drug in lungs instead of oropharynx by approx 15%)
- Choice of device: must consider patient age, coordination, dexterity, severity, preference
- Oral candidiasis: ↓ by rinsing mouth following inhalation of steriods; use space device
- Turbuhaler is breath-actuated (releases drug on inspiration); Suitable for people who are unable to coordinate MDI
What are 7 roles of the physiotherapist in respiratory failure?
- Recognize signs of respiratory failure (Type I vs Type II)
- Select appropriate management for people with respiratory distress, and respiratory failure
- O2 therapy is a drug - must be treated accordingly, prescribed by medical practitioner
- Be aware of potential complications / side-effects of O2 therapy
- Ensure correct application of O2 therapy (delivery device, flow rate, concentration)
- Select humidification where appropriate
- Observe & review technique of application of nebuliser and aerosol therapies