L13 Non-invasive ventilation Flashcards
1
Q
What is non invasive ventilation?
A
- Provision of ventilatory support to a person’s upper airway via a non-invasive interface
- Most commonly a mask
2
Q
What is BiPAP? What are the 2 other names?
A
Bilevel positive airway pressure
BiLevel = BiPAP = VPAP (variable positive airway pressure)
3
Q
What is CPAP?
A
single level pressure (continuous positive airway pressure). Not strictly NIV but considered in this lecture because of similarities.
4
Q
What is the 3 invasive mode of positive ventilatory support?
A
Invasive
- Endotracheal tube (ETT), nasotracheal or tracheostomy tube has been placed in the patient’s airway
- Connected to ventilator
- Intensive care unit (ICU)
5
Q
What are the 2 main ventilatory support? What are the 2 types of non-invasive ventilatory support?
A
6
Q
What are the 7 aims of NIV?
A
- 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
7
Q
What do NIV machines look like (ICU environment volume controlled ventilators)?
A
8
Q
What are the 5 NIV portable machines?
A
9
Q
What are the 4 NIV settings?
A
- 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
10
Q
How does bilevel work?
A
Pressure support (PS) = IPAP – EPAP
- Increase PS for increased tidal volume (minimum 4cm)
EPAP = PEEP = CPAP
11
Q
What are 4 characteristics of IPAP?
A
- 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)
12
Q
What are 4 characteristics of EPAP?
A
- 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
13
Q
What are 3 characteristics of ↑ FRC in EPAP?
A
- improves oxygenation
- reduces diaphragmatic effort
- offsets intrinsic positive end-expiratory pressure (PEEP) in patients with lung disease
14
Q
What are the 3 BiPAP as NIV modes?
A
- Spontaneous
- Spontaneous/ Timed
- Timed
15
Q
What are the 4 characteristics of spontaneous (S) BiPAP as NIV modes?
A
- 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
16
Q
What are the 2 characteristics of spontaneous/timed (S/T) BiPAP as NIV modes?
A
- 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
17
Q
What are the 3 characteristics of timed (T) BiPAP as NIV modes?
A
- 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.
18
Q
What are the 3 characteristics of CPAP modes?
A
- 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
19
Q
What are 4 characteristics of CPAP (continuous positive airway pressure)?
A
- Used for Obstructive Sleep Apnoea (OSA) – upper airway closure
- Does not require tidal volume augmentation
- Abolish apneas, upper airway resistance
- Home use
20
Q
What are the 5 other conditions responsive to CPAP?
A
- 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
21
Q
What are 6 contraindications of NIV? What must you have for intubation?
A
- 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
22
Q
What are 6 precautions of NIV? What must you have for intubation?
A
- 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
23
Q
What are the 4 potential complications with NIV use?
A
- 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
24
Q
What are the 3 probems related to pressure as potential complications with NIV use?
A
- Sinus pain
- Gastric insufflation
- Pneumothorax
25
What are the 3 probems related to airflow as potential complications with NIV use?
1. Dryness
2. Nasal congestion
3. Eye irritation
26
What are the 3 major potential complications with NIV use?
1. Severe hypoxaemia
2. Aspiration (eg. likely to vomit, feeling nauseous)
3. Hypotension
4. Mucous plugging
27
What are the 3 other complications with NIV use?
1. Claustrophobia
2. Air leaks from poor mask seal
* \*Pressure sores at the nasal bridge
28
What are the 3 interfaces of NIV?
29
What are 5 characteristics of mask as an interface of NIV?
1. Correct mask fit important for comfort and ventilator synchrony (ensure no leak)
2. Attention to skin condition as risk of pressure areas
3. Always check for **expiratory port/valve** (CO2 elimination) and **release valve**
* ****↑ CO2 retention --\> drowsy --\> life threatening
4. Full face vs nasal
5. **Do not over tighten masks, a tighter mask does not always mean less leak, but always means less comfort.**
30
What are 2 types/selections of mask in NIV?
31
What are 4 characteristics of humidification? What is the main point?
1. indications – thick secretions (eg CF), supplemental oxygen, mouth dryness (2 has no humidity)
2. practical considerations – place below patient mask and flow generator so condensation drains into humidification chamber
3. 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 )
32
\_\_\_\_\_\_\_ alone will not mobilise secretions (must be used in combination)
NIV
33
What is the NIV equipment set -up?
34
What are 4 NIV clinical applications?
1. Chronic Sleep Disorders (Sleep Laboratory)
2. Chronic Respiratory Failure (eg bridge to transplant) (Sleep Laboratory)
3. Acute respiratory failure (Sleep Laboratory, NIV team, treating Medical team, Physiotherapist)
4. Adjunct to Physiotherapy – secretion removal, exercise (Physiotherapist in collaboration with treating team)
35
What are the 11 recommendations for NIV after respiratory failure?
1. COPD exacerbations
2. Facilitation of weaning / extubation in patients with COPD
3. Cardiogenic Pulmonary Oedema Level 1 Evidence unresponsive to CPAP
4. Immunosuppressed patients
5. Cystic Fibrosis
6. Neuromuscular – spinal injuries, MND, DMD, SMA, Guillain Barre
7. Chest wall deformity – kyphoscoliosis
8. Thoracic trauma
9. Neurological – head injury, disorders of central breathing control
10. Respiratory muscle dysfunction – post polio
11. Post- surgical
36
What is acute hypercapnic for respiratory failure (ARF)?
Arterial blood gas derangement
1. pH 7.25 – 7.35 (Not for acidosis (\<7.25))
2. ↑ CO2 (\>45mm Hg)
3. Acute or acute-on-chronic respiratory failure
4. eg. COPD
**Acceptable for patients traditionally considered not suitable for intubation**
37
What is the 6 pathophysiology benefits of NIV in COPD (Acute Respiratory Failure) patients?
38
What are 6 results of NIV use in Acute Respiratory Failure (COPD)?
1. Decreased mortality by ~ 50%
2. Decreased need for intubation by ~ 60%
3. Reduction in complications by 52%
4. Reduced hospital stay by up to 2 days
5. Rapid improvement in pH and PaCO2 in 1st hour
6. Improvement in respiratory rate
39
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
40
How is an ABG done?
Stab deep into wrist to get artery (quite invasive) --\> no routinely done (only done if necessary)
41
What is the subjective evaulation and monitoring?
1. Patient comfort
1. How is your breathing feeling?
2. Are you getting a big enough breath?
3. Does the breath last long enough?
4. Are the breaths coming too quickly, not quickly enough?
5. Do you have enough time to breathe out?
6. Is it too hard to breathe out?
2. **Respiratory comfort = unloading of respiratory muscles**
42
What is the objective evaulation and monitoring?
1. Conscious level
2. Breathing pattern / use of access m.
3. Respiratory rate
4. Heart rate
5. Oxygen saturations
6. Adjust FiO2 and EPAP to maintain SpO2
7. Aim for lowest FiO2 possible and minimum pressure support of 4
43
What are 4 different conditions for evaluation and monitoring?
1. Gastric Swallowing of Air (Aerophagia)
1. May cause the patient to experience nausea during physio treatment → may be similar to reflux symptoms
2. NIV pressures may need to be decreased if persists
2. Haemoptysis (bleeding)
1. If intermittent haemoptysis – can continue NIV as airway clearance should be continued
3. Pneumothorax
1. If ICC insitu - NIV use can be continued
2. Loculated pneumothorax
1. If stable (usually no ICC) can continue BiPAP
4. Actively monitor symptoms of SOB, SpO2 & chest pain
44
What are the 4 characteristics of NIV and cystic fibrosis?
1. Reduces respiratory muscle fatigue, allows better tolerance of treatments
2. Prevents airway closure during techniques (EPAP)
3. Additionally humidification assists mucociliary clearance, oxygen aids hypoxemia
4. Nocturnal use – improves gas exchange and slows progression of chronic respiratory failure
45
What are 5 postives of NIV and cystic fibrosis?
1. airway clearance may be easier with NIV
2. patient preference for NIV
3. may help improve exercise tolerance
4. fatigue lower with NIV compared to CPT
5. RR lower with NIV
46
What are 3 negatives of NIV and cystic fibrosis?
1. no measures of long term effects – survival, QoL
2. no differences in pre/post lung function
3. no evidence for increased sputum volume expectorated
* Must do ACBT in conjunction with NIV (cannot be used alone)
47
What are 6 Physiotherapy Applications in CF?
1. Facilitate sputum clearance
2. Reduce work of breathing
3. Increase patient tolerance to airway clearance techniques
4. Enhance collateral ventilation
5. Ventilatory support for exercise
6. Overcome pain limitation post #
48
What is Case 1 for acute exacerbation look like?
49
What does exercise with NIV look like?
50
What are 4 characteristics of exercise with NIV in patients with chronic lung disease?
1. ↓ WOB
2. unloading respiratory muscles
3. ↓fatigue respiratory muscles
4. ↓ exertional dyspnoea
51
What are 7 potential effects of exercise with NIV in patients with chronic lung disease?
1. ↑ tidal volume
2. ↑ MV : more advantageous pattern of breathing during exercise
3. ↑ alveolar ventilation and gas exchange
4. ↓ dynamic hyperinflation
5. ↓ heart rate
6. ↑ intensity and endurance of exercise
7. 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
52
What are 8 characteristics of Patient Set-up with NIV?
1. Explain procedure to patient. Select mask. Demonstrate before applying. Select settings
2. Increase IPAP according to patient comfort, respiratory rate and breathing pattern and to provide an adequate tidal volume
3. Adjust FiO2 and EPAP to maintain SpO2
1. Aim for lowest FiO2 possible and EPAP\<10cmH20
2. There should always be a minimum of 4 cm PS (ie IPAP should always be at least 4 cm greater the EPAP)
4. Ensure machine is cycling between IPAP & EPAP
5. Check exhalation ports are free from obstruction
6. Remain with patient throughout first application. Demonstrate mask release
7. Medical staff may perform ABG prior to application and 1 hour after initiation (for acute hypercapnic respiratory failure)
