Mechanical and NI Ventilation Flashcards
1
Q
Principles of Mechanical Ventilation
A
- positive pressure ventilation
- delivers “breath” to get O2 in and CO2 out
- gas pumped in during inspiration (Ti)
- patient passively expires (Te)
- Ti + Te = respiratory cycle/”breath”
2
Q
Indications for mechanical ventilation
A
- respiratory failure
- patients at risk of respiratory failure
- unsustainable levels of cardiac work
- unsustainable WOB
- airway protection
- large secretions load
- reversible condition
3
Q
Symptoms showing need for ventilation
A
- spontaneous ventilation inadequate to maintain gas exchange
- PaO2 <60mmHg, PaCO2 >49mmHg
- metabolic cost of breathing increases to 30% (normal 5%)
- other symptoms:
- increased WOB
- accessory muscle use
- sweating
- increased HR/RR/BP
- confusion, aggretion
- secretions
4
Q
Effects of MV
A
- increases gas exchange
- decreases WOB
- improves cardiac function
- allows oxygen to be used by other organs
- multi organ failure
- burns
- sepsis
- improves thoracic stability
- increases alveolar ventilation
5
Q
Controlled mandatory ventilation (CMV)
A
- machine breathes totally for patient
- pt often heavily sedated
- used in OT or very ill patient
- set breaths/min
- causes resp weakness and infection
6
Q
Synchronised intermittent mandatory ventilation (SIMT)
A
- patient takes some breaths, machine takes others
- machine senses when patient is taking a breath
- used in most patients
- set resp rate (decrease as patient improves)
- 3 types of breaths
7
Q
SIMT advantages
A
- improved comfort
- no breath stacking
- reduced resp muscle atrophy
8
Q
SIMT breath types
A
- Controlled
- triggered and delivered by ventilator according to prescribed settings
- Assisted
- triggered by pt
- assisted by ventilator
- same shape as controlled breath
- Spontaneous
- triggered by pt
- assisted by ventilator (PS)
- volume not controlled
9
Q
Assist Control mode
A
- pt receives either Mandatory or Assisted breaths
- pt triggers ventilator
- assisted breath is identical in duration and magnitude as a mandatory breath
10
Q
Pressure Support Breathing (PS/PEEP)
A
- spontaneous breathing by pt
- supported by pressure support and PEEP
11
Q
Advantages of PEEP
A
- reduces bronchiolar and alveolar collapse
- holds open at end of inspiration
- increases FRC
- allows lower FiO2
- reduces shunting
12
Q
Disadvantages of PEEP
A
- reduces cardiac output
- increases airway pressure
13
Q
Pressure Support
A
- augmented pressure during spontaneous breaths
- decreased WOB
- increases tidal volume
- pt initiates breath, PS “lifts up” breath
- pt regulates own tidal volume and resp rate
14
Q
Flowby mode
A
- continuous baseline flow
- reduces dead space
- reduces WOB to trigger a breath
15
Q
Advantages of spontaneous breathing
A
- less disuse atrophy
- decreased weaning time
- less need for sedation
- can exercise and mobilise more easily
- less infection risk
16
Q
Volume control
A
- tidal volume pre-set
- RR set
- inspiratory pressure variable
- if stiff lung high pressure (PIP > 35mmH2O)
- if compliant lung low pressure
- CMV
- SIMT
17
Q
Pressure control
A
- inspiratory pressure pre-set
- RR set
- tidal volume variable
- improved recruitment (long time constants)
- better if lung easily damaged by high pressure
- paediatrics
- severe asthma
- COPD
18
Q
Bilevel ventilation
A
- form of pressure controlled ventilation
- 2 levels of PEEP maintained to inflate alveoli
- less injury to lungs
- allows spontaneous breaths
- assists patient initiated breaths with pressure support
19
Q
Nitric oxide
A
- used to improve oxygenation
- vasodilator of pulmonary circulation
- used in acute resp distress syndrome
- used in pulmonary hypertension
20
Q
High frequency oscillations
A
- small volumes at high rate
- oscillation removes CO2
21
Q
Pulmonary side effects of ventilations
A
- maldistribution of ventilation
- progressive atelectasis
- hyperinflation
- V/Q mismatch
- decrease in surfactant
- increased extravascular lung water
22
Q
Ventilator induced lung injuries
A
- barotrauma
- volutrauma
- atelectrauma
- biotrauma
23
Q
Other side effects of ventilation
A
- ventilator associated pneumonia
- decreased cardiac output
- DVT
- gastric alceration
- critical care myopathy
- disuse atrophy of diaphragm
- ICU psychosis
24
Q
Prevention of side effects
A
- humidification
- positioning
- percussion
- manual hyperinflation
- leg exercises, passive movements, TEDs, SCDS
- exercises
- mobilise while ventilated
25
Q
Fix hypoxaemia during MV
A
- increase FiO2
- auscultation
- check settings
- suction
- CXR
- manually bag
- bronchoscope
26
Q
Low pressure alarm
A
- manually bag
- check connection
- check ventilator function
27
Q
Low TV alarm
A
- as for low pressure alarm
- biting of ETT
- fatigue, over sedation
28
Q
High resp rate alarm
A
- anxiety, pain
- fatigue
- may need increased pressure support
29
Q
NIV Contraindications
A
- CV instability
- airway obstruction
- resp or facial trauma
- severe haemoptysis
- undrained pneumothorax
- severely depressed level of conciousness
30
Q
NIV Precautions
A
- bullae, cystic disease
- GCS <9, unprotected airway
- inability to clear secretions
- facial pressure areas
- GOR
- persistant air leaks
31
Q
NIV Complications
A
- pressure
- sinus pain
- gastric insufflation
- pneumothorax
- airflow
- dryness
- nasal congestion
- eye irritation
- major complications
- severe hypoxaemia
- aspiration
- hypotension
- mucous plugging
- other complications
- claustrophobia
- air leaks
- pressure sores
32
Q
Monitoring of NIV patient
A
- patient comfort
- respiratory comfort
- conscious level
- breathing pattern, use of acc muscles
- RR, HR, SpO2
33
Q
Benefits of NIV with exercise
A
- decreased WOB
- decreased fatigue of resp muscles
- increased TV
- increased gas exchange
- decreased dynamic hyperinflation
- decreased HR
- increased intensity and endurance
- secondary improved oxygenation and perfusion of peripheral muscles
