Advanced Oxygen Therapy & Humidification Flashcards
What is important for effective function of cilia?
Depth of the periciliary (sol) layer
How can oxygen therapy cause impaired sputum clearance?
Causes dehydration of the airways & increased viscosity of sputum = impaired sputum clearance
What are the 2 categories of humidifiers?
- Home-based vaporisers
- Hospital/personal
What is the function of home-based vaporisers?
- Increases H2O content of room
- Typically short term use
- Can have issues with dampness (not used in hospitals)
What is a common type of hospital/personal humidifiers?
High flow nasal prongs (HFNP)
What are the benefits of HFNP?
- Maintains adequate oxygenation plus humidification
- Provides small amount of positive end expiratory pressure
- Patient still able to talk, eat & drink
- Precise FiO2 delivery (21-80%)
What are the CIs to HFNP?
- Significant facial trauma
- Patients requiring continuous nebulisers (can use spacer with HFNP)
- Any condition where positive pressure would be a problem (e.g. undrained pneumothorax)
What are the considerations for HFNP delivery?
- High flow will help reduce WOB
- FiO2 should be titrated to SpO2
- Encourage nose breathing (mouth closed = PEEP)
What is a disadvantage of HFNP?
- Humidifier chambers do not have a portable battery (i.e. need to be plugged in)
- Need to consider other options for mobilisation
What physio techniques can be combined with HFNP?
- Cough/huff
- PEP devices (bubble, flutter)
- Percs & vibes
- ACBT/FET
What is the function of nebulisers?
- Deliver high flow of air/O2 through small aperture
- Causes aerosolisation of particles
- Can be used for medications, H2O (humidification), saline
What are the different types of nebulisers?
- Wall oxygen/air-based
- Ultrasonic
What is induced sputum?
- Specific procedure to obtain a sputum sample from some not currently producing sputum
What 2 main conditions is induced sputum used for?
- Tuberculosis: Airborne infection, mostly asymptomatic
- Pneumocystis pneumonia (PCP): Fever, non-productive cough (sputum too viscous), SOB
What are the precautions of induced sputum?
- Need gown, gloves, duckbill mask
- Need to be in a negative pressure room
How does induced sputum work?
- Inhalation of nebulised hypertonic saline
- Movement of fluid draws disease cells across alveolar membrane to allow detection on sputum sample
- Induces coughing & salivation
When are the indications for humidification?
- Patient requires continuous O2 >24 hours (especially at high flow rates)
- Patient already has problems with sticky sputum
What are the limits of O2 therapy?
If patient cannot maintain adequate oxygenation with O2 flow they may need positive pressure
What are the two types of positive pressure for augmentation of oxygenation?
- Invasive ventilation (ICU)
- Non-invasive ventilation (CPAP, BiPAP)
What is invasive ventilation?
- Mechanical ventilation
- Machine-supported breaths delivered deep into lungs, bypassing usual nose/mouth route
How is air invasively pumped into lungs?
- Need an artificial airway
- Either endotracheal tube or tracheostomy
How are endotracheal tubes positioned?
- Inserted through the mouth & larynx
- Held in place by cuff/balloon & tapes
- Should terminate 3-5cm above carina on CXR
- Usually limited to 7 days due to risk of damage to airways & larynx
What is a tracheostomy?
- Direct opening into an airway, bypassing upper airway
- Ventilation > 7-10 days
- Reversible, but may scar
What are the types of tracheostomies?
- Mini tracheostomy: Secretion management
- Surgical: General anaesthetic in OT
- Percutaneous: Local anaesthetic in ICU
- Cricothyroidotomy: Emergency
What are the types of tracheostomy tubes?
- Mini tracheostomy
- Portex
- Shiley (long-term use)
- Silver (permanent use)
What type of tracheostomy tubes do mechanically ventilated patients require?
Cuffed tubes
What is the difference between an inflated & deflated cuff?
- Inflated: Isolates upper airway from lower, air cannot flow through upper airway
- Deflated: Allows air to move through upper airway
What are the issues associated with under inflation of the cuff?
- Aspiration/secretion
- Under ventilation in ventilated patient
What are the issues associated with over inflation of the cuff?
- Tracheomalacia
- Tracheo-oesophageal fistula
- Inflammation of tracheal wall
- Formation of granulation tissue
- Tracheoinnominate fistula
- Tracheal stenosis
What pressure of H2O is acceptable on a manometer?
- 15-25cm H2O
- May be higher in ventilated patients
What are the indications for temporary tracheostomy?
- Prolonged intubation (<10-14 days) - decreases risks & side effects of ET tube
- Comfort
- Long term unconsciousness/coma
- Glossal muscle paralysis/inability to swallow
- Loss of laryngeal reflexes
- Foreign body
- Severe neck/mouth injuries
- Inhalation injuries (e.g. smoke)
What are the benefits of temporary tracheostomy?
- Decreases aspiration
- Decreases airway compression/obstruction
- Decreases deadspace by up to 50%
- Decreases sedation requirement
- Aids secretion removal
- Facilitates normal eating & drinking
What are the consequences of temporary tracheostomy?
- Loss of speech (unless speaking valve)
- Increased infection risk
- Decreased humidification
- Decreased cough reflex
- Increased aspiration risk
- Decreased appetite
How does a tracheostomy affect humidification?
- Bypasses upper airway, compromising humidification
- Lower airways become drier
- Cilia of lower airways less effective at clearing secretions
What are the signs of poor humidification?
- Secretions sticking to inside of TT
- Thicker sputum
- Absence of sputum
- Bleeding from tracheal wall
- Atelectasis due to sputum plug
How can humidification & heat be added if nasopharnyx is bypassed?
- Hydration
- Tracheostomy mask
- Swedish nose
- Laryngectomy-permanent tracheostomy protector
- Heated water
- Heat & moisture exchanges
- Nebulisers
- Steam inhalers
What are the pros & cons of heat moisture exchangers (HME)?
Pros:
- Portable, convenient
- Can be placed directly onto hub of TT or used within ventilator circuit
Cons:
- Provide less humidification than hot water humidifiers
- Unsuitable if copious secretions
What is the benefit of permanent tracheostomy?
Maintains airway when there is neurological or anatomical abnormality
