L13 Non-invasive ventilation Flashcards
What is non invasive ventilation?
- Provision of ventilatory support to a person’s upper airway via a non-invasive interface
- Most commonly a mask
What is BiPAP? What are the 2 other names?
Bilevel positive airway pressure
BiLevel = BiPAP = VPAP (variable positive airway pressure)
What is CPAP?
single level pressure (continuous positive airway pressure). Not strictly NIV but considered in this lecture because of similarities.
What is the 3 invasive mode of positive ventilatory support?
Invasive
- Endotracheal tube (ETT), nasotracheal or tracheostomy tube has been placed in the patient’s airway
- Connected to ventilator
- Intensive care unit (ICU)
What are the 2 main ventilatory support? What are the 2 types of non-invasive ventilatory support?

What are the 7 aims of NIV?
- To improve gas exchange
- To offload respiratory muscles, reduce WOB and relieve dyspnoea
- To avoid the need for invasive ventilatory support
- To maximise QoL and function
- To prolong survival
- To improve sleep duration and quality
- To enhance airway clearance, atelectasis management and exercise with physiotherapy
What do NIV machines look like (ICU environment volume controlled ventilators)?

What are the 5 NIV portable machines?

What are the 4 NIV settings?
- Cycles between 2 levels of positive pressures
- IPAP – inspiratory positive airway pressure
- EPAP – expiratory positive airway pressure
-
Pressure support (swing or delta)
- IPAP – EPAP = PS
How does bilevel work?
Pressure support (PS) = IPAP – EPAP
- Increase PS for increased tidal volume (minimum 4cm)
EPAP = PEEP = CPAP

What are 4 characteristics of IPAP?
- Acts as an augmenting pressure by supporting inspiratory efforts
- Increases tidal volume, minute ventilation (TVxRR), reduces CO2 levels
- Rest respiratory muscles and reduces work of breathing
- IPAP > EPAP (always)

What are 4 characteristics of EPAP?
- Acts as a splinting pressure to prevent airway closure at end-expiration
- Positive pressure also assists secretion removal
- Recruits atelectatic regions of lung via collateral ventilation thereby improving ventilation/perfusion matching
- Increases the functional residual capacity (FRC)
- improves oxygenation
- reduces diaphragmatic effort
- offsets intrinsic positive end-expiratory
- pressure (PEEP) in patients with lung
- disease

What are 3 characteristics of ↑ FRC in EPAP?
- improves oxygenation
- reduces diaphragmatic effort
- offsets intrinsic positive end-expiratory pressure (PEEP) in patients with lung disease
What are the 3 BiPAP as NIV modes?
- Spontaneous
- Spontaneous/ Timed
- Timed

What are the 4 characteristics of spontaneous (S) BiPAP as NIV modes?
- Inspiratory and expiratory levels set independently
- Triggering EPAP to IPAP reliant on patient effort and flow
- Respiratory rate and cycle determined by patient
- Mode commonly used by physiotherapists

What are the 2 characteristics of spontaneous/timed (S/T) BiPAP as NIV modes?
- Device augments breaths initiated by patient (as with Spontaneous Mode)
- Delivers additional breaths if spontaneous effort falls below the “back-up” rate set by clinician

What are the 3 characteristics of timed (T) BiPAP as NIV modes?
- Clinician sets the respiratory cycle – IPAP, EPAP and RR, time spent in IPAP
- All breaths are machine generated
- S/T mode usually most suitable modality except with end stage neuromuscular disease.

What are the 3 characteristics of CPAP modes?
- Device provides single level of continuous positive pressure throughout respiratory cycle = EPAP alone
- Patient controls all aspects of the respiratory cycle including respiratory rate and inspiratory time
- CPAP has been shown to be effective in patients with cardiogenic pulmonary oedema, and post-operative atelectasis

What are 4 characteristics of CPAP (continuous positive airway pressure)?
- Used for Obstructive Sleep Apnoea (OSA) – upper airway closure
- Does not require tidal volume augmentation
- Abolish apneas, upper airway resistance
- Home use

What are the 5 other conditions responsive to CPAP?
- Acute respiratory failure (Type 1 – hypoxemia)
- Cardiogenic Pulmonary Oedema
- Diffuse pneumonia
- Post-operative atelectasis
- Overweight –> fatty tissue around neck (close down) without muscle contraction +/- pathology

What are 6 contraindications of NIV? What must you have for intubation?
- Cardiovascular instability
- Affects pre and after load of heart
- Airway obstruction
- Respiratory or facial trauma/ burns
- Severe haemoptysis
- Undrained pneumothorax
- Stable or drained = no contraindication
- Severely depressed level consciousness
- Cannot use with sleeping (use for active clearance)
Consider appropriateness and contingency plans for intubation
What are 6 precautions of NIV? What must you have for intubation?
- Bullae/cystic disease
- GCS < 9, unprotected airway
- Inability to clear secretions
- Facial pressure areas
- GOR
- Persistent air leaks
Consider appropriateness and contingency plans for intubation
What are the 4 potential complications with NIV use?
- Problems related to pressure:
- Sinus pain
- Gastric insufflation
- Pneumothorax
- Problems related to airflow:
- Dryness
- Nasal congestion
- Eye irritation
- Major complications:
- Severe hypoxaemia
- Aspiration (eg. likely to voamit, feeling nauseous)
- Hypotension
- Mucous plugging
- Other complications:
- Claustrophobia
- Air leaks from poor mask seal
- *Pressure sores at the nasal bridge
What are the 3 probems related to pressure as potential complications with NIV use?
- Sinus pain
- Gastric insufflation
- Pneumothorax
What are the 3 probems related to airflow as potential complications with NIV use?
- Dryness
- Nasal congestion
- Eye irritation
What are the 3 major potential complications with NIV use?
- Severe hypoxaemia
- Aspiration (eg. likely to vomit, feeling nauseous)
- Hypotension
- Mucous plugging
What are the 3 other complications with NIV use?
- Claustrophobia
- Air leaks from poor mask seal
- *Pressure sores at the nasal bridge
What are the 3 interfaces of NIV?

What are 5 characteristics of mask as an interface of NIV?
- Correct mask fit important for comfort and ventilator synchrony (ensure no leak)
- Attention to skin condition as risk of pressure areas
- Always check for expiratory port/valve (CO2 elimination) and release valve
- ↑ CO2 retention –> drowsy –> life threatening
- Full face vs nasal
- Do not over tighten masks, a tighter mask does not always mean less leak, but always means less comfort.

What are 2 types/selections of mask in NIV?

What are 4 characteristics of humidification? What is the main point?
- indications – thick secretions (eg CF), supplemental oxygen, mouth dryness (2 has no humidity)
- practical considerations – place below patient mask and flow generator so condensation drains into humidification chamber
- high flow rates + low relative humidity associated with NIV can compromise function of upper airway mucosa risk sputum retention with airway dehydration
Should ALWAYS use humidification
- Cells hydrated on surface level (cilia can move appropriate –> aqueous layer can start working to remove secretions )

_______ alone will not mobilise secretions (must be used in combination)
NIV
What is the NIV equipment set -up?

What are 4 NIV clinical applications?
- Chronic Sleep Disorders (Sleep Laboratory)
- Chronic Respiratory Failure (eg bridge to transplant) (Sleep Laboratory)
- Acute respiratory failure (Sleep Laboratory, NIV team, treating Medical team, Physiotherapist)
- Adjunct to Physiotherapy – secretion removal, exercise (Physiotherapist in collaboration with treating team)
What are the 11 recommendations for NIV after respiratory failure?
- COPD exacerbations
- Facilitation of weaning / extubation in patients with COPD
- Cardiogenic Pulmonary Oedema Level 1 Evidence unresponsive to CPAP
- Immunosuppressed patients
- Cystic Fibrosis
- Neuromuscular – spinal injuries, MND, DMD, SMA, Guillain Barre
- Chest wall deformity – kyphoscoliosis
- Thoracic trauma
- Neurological – head injury, disorders of central breathing control
- Respiratory muscle dysfunction – post polio
- Post- surgical
What is acute hypercapnic for respiratory failure (ARF)?
Arterial blood gas derangement
- pH 7.25 – 7.35 (Not for acidosis (<7.25))
- ↑ CO2 (>45mm Hg)
- Acute or acute-on-chronic respiratory failure
- eg. COPD
Acceptable for patients traditionally considered not suitable for intubation
What is the 6 pathophysiology benefits of NIV in COPD (Acute Respiratory Failure) patients?

What are 6 results of NIV use in Acute Respiratory Failure (COPD)?
- Decreased mortality by ~ 50%
- Decreased need for intubation by ~ 60%
- Reduction in complications by 52%
- Reduced hospital stay by up to 2 days
- Rapid improvement in pH and PaCO2 in 1st hour
- Improvement in respiratory rate
What are the NIV settings?
Typical initial ventilator settings for bi-level pressure support in a patient with acute hypercapnic respiratory failure due to COPD

How is an ABG done?
Stab deep into wrist to get artery (quite invasive) –> no routinely done (only done if necessary)
What is the subjective evaulation and monitoring?
- Patient comfort
- How is your breathing feeling?
- Are you getting a big enough breath?
- Does the breath last long enough?
- Are the breaths coming too quickly, not quickly enough?
- Do you have enough time to breathe out?
- Is it too hard to breathe out?
- Respiratory comfort = unloading of respiratory muscles
What is the objective evaulation and monitoring?
- Conscious level
- Breathing pattern / use of access m.
- Respiratory rate
- Heart rate
- Oxygen saturations
- Adjust FiO2 and EPAP to maintain SpO2
- Aim for lowest FiO2 possible and minimum pressure support of 4
What are 4 different conditions for evaluation and monitoring?
- Gastric Swallowing of Air (Aerophagia)
- May cause the patient to experience nausea during physio treatment → may be similar to reflux symptoms
- NIV pressures may need to be decreased if persists
- Haemoptysis (bleeding)
- If intermittent haemoptysis – can continue NIV as airway clearance should be continued
- Pneumothorax
- If ICC insitu - NIV use can be continued
- Loculated pneumothorax
- If stable (usually no ICC) can continue BiPAP
- Actively monitor symptoms of SOB, SpO2 & chest pain
What are the 4 characteristics of NIV and cystic fibrosis?
- Reduces respiratory muscle fatigue, allows better tolerance of treatments
- Prevents airway closure during techniques (EPAP)
- Additionally humidification assists mucociliary clearance, oxygen aids hypoxemia
- Nocturnal use – improves gas exchange and slows progression of chronic respiratory failure

What are 5 postives of NIV and cystic fibrosis?
- airway clearance may be easier with NIV
- patient preference for NIV
- may help improve exercise tolerance
- fatigue lower with NIV compared to CPT
- RR lower with NIV
What are 3 negatives of NIV and cystic fibrosis?
- no measures of long term effects – survival, QoL
- no differences in pre/post lung function
- no evidence for increased sputum volume expectorated
- Must do ACBT in conjunction with NIV (cannot be used alone)
What are 6 Physiotherapy Applications in CF?
- Facilitate sputum clearance
- Reduce work of breathing
- Increase patient tolerance to airway clearance techniques
- Enhance collateral ventilation
- Ventilatory support for exercise
- Overcome pain limitation post #
What is Case 1 for acute exacerbation look like?


What does exercise with NIV look like?

What are 4 characteristics of exercise with NIV in patients with chronic lung disease?
- ↓ WOB
- unloading respiratory muscles
- ↓fatigue respiratory muscles
- ↓ exertional dyspnoea
What are 7 potential effects of exercise with NIV in patients with chronic lung disease?
- ↑ tidal volume
- ↑ MV : more advantageous pattern of breathing during exercise
- ↑ alveolar ventilation and gas exchange
- ↓ dynamic hyperinflation
- ↓ heart rate
- ↑ intensity and endurance of exercise
- 2˚ improved oxygenation and perfusion of peripheral muscles
However no objective evidence currently
- Documented successful use as a bridge to transplantation
- If patient can maintain exercise
What are 8 characteristics of Patient Set-up with NIV?
- Explain procedure to patient. Select mask. Demonstrate before applying. Select settings
- Increase IPAP according to patient comfort, respiratory rate and breathing pattern and to provide an adequate tidal volume
- Adjust FiO2 and EPAP to maintain SpO2
- Aim for lowest FiO2 possible and EPAP<10cmH20
- There should always be a minimum of 4 cm PS (ie IPAP should always be at least 4 cm greater the EPAP)
- Ensure machine is cycling between IPAP & EPAP
- Check exhalation ports are free from obstruction
- Remain with patient throughout first application. Demonstrate mask release
- Medical staff may perform ABG prior to application and 1 hour after initiation (for acute hypercapnic respiratory failure)