Lect 5-Prof.NorAzim (18.8.2022)-Invasive and Non-Invasive Ventilation.pdf

-Invasive and Non-Invasive Ventilation

1. Invasive and
Non-Invasive
Ventilation
Adapted from:
Mechanical Ventilation of the Critically Ill
Lecture by Dr Wong Kwang Kong

2. •Polio epidemic in
1950’s

3. Iron lung donated by the
family of Mr. Barton Hebert
of Covington, Louisiana, who
had used the device from
late 1950s until his death in
2003.

4. Respiratory Failure
•Lung failure: failure of lung parenchyma (Type
I)
-low PaO
2and normal or low PaCO
2
•Pump failure: failure of ventilatory function
(Type II)
-low PaO
2and high PaCO
2
•Rarely occur in isolation in critically ill patients

5. Indications for ventilation:
clinical signs of respiratory
distress

6. Initiating mechanical ventilation
•Invasive vsnon-invasive techniques
•determined by the interface used
•the interface should guarantee effective pneumatic seal to
deliver positive pressure ventilation
•generally, two kinds of interface are used:
•endotracheal tube (or tracheostomy): invasive approach
•mask: the non-invasive approach

7. •An artificial bypass of the upper airway to the lower third of the trachea,
with a good pneumatic seal.
•It allows
•airway protection from major aspiration
•protection of upper airway and gastroenteric tract from positive
pressure
•relief from upper airway obstruction
•easy access to the airway for suction and bronchoscopy
•low dead space
•stable and safe connection between ventilation apparatus and patient
Invasive ventilation: endotracheal
tube

8. •Disadvantages:
•Loss of protective functions of upper airway: gas heating, gas
humidificationand protection from infections
•Decrease of cough effectiveness
•Increase of airway resistance
•Risk of different types of damage of the bypassed airway
•Loss of the ability to speak
Invasive ventilation: endotracheal
tube

9. 1 Support arm
2 Inspiratory port with filter
3 Active humidifier
4 Inspiratory line with watertrap
5 Y-piece
6 Expiratory line with watertrap
7 Expiratory port
8 Patient connector
9 Proximal flow –pressure sensor
10 Nebuliser
HME: Heat Moisture Exchanger
(instead of Active Humidifier)

11. Types of mechanical ventilation breaths can be distinguished based on:
•Breath initiation
•Inspiration
•Cycling to exhalation
Pressure
Support
SIMV

12. Types of mechanical ventilation breaths can be distinguished based on:
•Breath initiation
•Inspiration
•Cycling to exhalation
Pressure
Support
SIMV

13. •Machine-initiation
•the breath starts on a time basis, according to the set respiratory
frequency
•can only take place only in the modes that include a control for
frequency
•Patient-initiation
•the breath starts upon call from the patient, by means of an
inspiratory trigger, pressure-based or flow-base
Breath initiation: machine vspatient

14. Patient initiation: pressure trigger
•With pressure-trigger
•the ventilator watches the airway pressure during exhalation
•when the patient contracts his inspiratory muscles, the airway
opening pressure drops below the baseline
•when this drop reaches a pressure threshold defined by the
user, the machine responds by starting the inspiratory phase

15. Patient initiation: flow trigger
•With flow-trigger
•the ventilator watches the airflow
•when the patient contracts his inspiratory muscles, the airflow
reverses from expiratory or zero to inspiratory values
•when the inspiratory flow generated by the patient reaches the
threshold set by the user (usually 2 or 3 L/min), the machine
responds

16. Types of mechanical ventilation breaths can be distinguished based on:
•Breath initiation
•Inspiration
•Cycling to exhalation
Pressure
Support
SIMV

17. Volume-Controlled Ventilation (VCV)
•In this mode the tidal volume (Vt) is preset.
•Either Controlled or Assist Control Ventilation (ACV)/
SynchronisedIntermittent Mandatory Ventilation (SIMV):
depending on the lack or presence of patient’s inspiratory
activity

18. Handbook of Mechanical Ventilation –Intensive Care Foundation

19. Pressure-Controlled Ventilation (PCV)
•In this mode inspiration is promoted by a pre-set pressure
•Either Controlled or Assist Control Ventilation (ACV)/Synchronised
Intermittent Mandatory Ventilation (SIMV):depending on the lack or
presence of patient’s inspiratory activity

20. Handbook of Mechanical Ventilation –Intensive Care Foundation

21. SynchronisedIntermittent Mandatory
Ventilation (SIMV)
•If the patient makes no respiratory effort the mandatory breaths are
delivered at a regular frequency
•If inspiratory effort is made when a mandatory breath is due
(synchronisationtime window), then the ventilator will synchronise
with the patient’s efforts and deliver the set mandatory breath.
•However, if the patient is breathing at a rate greater than the set rate
then the ventilator will deliver a pressure supported breath (if Pressure
Support is set) for each of the patient breaths above the pre-set
frequency.

22. Assist-Control (AC) Ventilation
•The mandatory breath can be fully controlled if the patient is not
triggering the ventilator or assisted if the patient is able to trigger the
ventilator

23. Pressure Support Ventilation (PSV)
•This is based on spontaneous breaths assisted by a pre-set pressure
Spontaneous breathing with CPAP
•All breaths are fully spontaneous, and the inspiratory pressure is
ideally equal to the set PEEP level
•Technically, when applied with a mechanical ventilator, spontaneous
breathing with CPAP is identical to PSV with a pressure support of
zero

24. Handbook of Mechanical Ventilation –Intensive Care Foundation

25. Pressure-regulated volume control
(PRVC)
•The inspiratory pressure is automatically adapted, breath by breath, to
achieve a target tidal volume.
•This principle allows a high degree of freedom for patient-ventilator
interaction within each breath, and the simultaneous control of the
average tidal volume

26. Biphasic pressure modes
•Biphasic positive airway pressure ventilation(BIPAP) or BILEVEL,
BIVENT
•In these modes, the ventilator controls only pressure, which moves
between a lower and an upper baseline, at a given user-set
frequency and duty cycle.
•If the patient has a spontaneous respiratory activity, the
spontaneous breaths are freely superimposed on the moving
pressure baseline, independently from the phase of the ventilator
cycle.

27. Biphasic pressure modes
•Airway Pressure Release Ventilation (APRV)
•is similar in concept to BIPAP, with particular settings
•The patient is maintained at a fairly high CPAP level that is
intermittently released to a much lower CPAP level for a short
time
•The intermittent release and resumption of the upper CPAP
level generates alveolar ventilation that augments the
ventilation provided by spontaneous breathing

28. Types of mechanical ventilation breaths can be distinguished based on:
•Breath initiation
•Inspiration
•Cycling to exhalation
Pressure
Support
SIMV

29. •When controlled by the machine, cycling is normally time-based.
•Time cycling means that the ventilator switches to exhalation as
soon as the set inspiratory time (Ti) is elapsed.
•The Tican be set by different means, i.e. directly as a time in
seconds, or indirectly depending on the combination of different
settings
Cycling to exhalation

30. •During exhalation, the ventilator controls a baseline pressure, which
can be set at zero or at positive levels commonly defined as Positive
End-Expiratory Pressure/Continuous Positive Airway Pressure
(PEEP/CPAP)
•PEEP works on the respiratory system by artificially increasing the
functional residual capacity (FRC)
PEEP/CPAP

32. Weaning
From
Mechanical
Ventilation

33. Before weaning, think of the following:
1.Has the underlying condition improved?
2. Is the patient’s general condition optimal?
3.Have potential airway problems been identified & remedied?
4. Is breathing adequate?

35. Spontaneous Breathing Trial (SBT)
•Pressure Support Ventilation of 5-7 cmH
2O and low level of PEEP (e.g. 5
cmH
20)
or using a T-piece circuit (rarely done in Malaysia)
•Allow 30-120 minutes of SBT
•Assess extubation readiness at the end of the trial:
•Rapid Shallow Breathing Index, RSBI (rate/exp TV) < 100
•Acceptable gas exchange on ABG
•Stable clinical respiratory and haemodynamicsparameters

36. Non-Invasive
Ventilation
(NIV)

38. NIV mask

40. Non-Invasive Ventilation
•Requirements:
•At least some residual ability of spontaneous breathing (the need for
full mechanical support is an absolute contraindication)
•No estimated need of high levels of positive pressure
•Estimated low risk associated with temporary disconnection from
ventilator
•Haemodynamicstability
•Good cooperation from the patient
•The ability of the patient to protect his own airway
•No acute facial trauma, skull base fracture, or recent digestive surgery

41. Indications
•COAD
•Pulmonary oedema
•Hypoxaemicrespiratory failure
•CAP
•Nosocomial pneumonia
•Aspiration pneumonia
•Chest trauma
•ARDS/ALI
•Respiratory failure in immunocompromised patients
•Weaning of ventilatory support

42. Absolute contraindications
•Cardiorespiratory arrest
•Unstable haemodynamics
•Severe arrhythmias
•Reduced level of consciousness
•Inability to protect airway –bulbar palsy
•Uncooperative patient

43. Relative contraindications
•Factors that make it difficult to create a seal with mask
•Facial trauma
•Facial deformity
•Recent facial surgery
•Conditions where air swallowing may cause problems
•Post-oesophagectomy(anastomotic breakdown)
•Cases where frequent removal of mask is necessary
•To clear secretions

44. Complications
•Air leaks
•Mask problems
•Discomfort
•Nasal bridge ulceration
•Facial erythema
•Pressure and flow related
•Nasal congestion
•Eye irritation
•Aerophagia –NG tube

45. Factors necessitating intubation
•Respiratory arrest
•Respiratory pauses, gasping
•Reduced consciousness
•Haemodynamicinstability
•RR > 35/min
•PaO
2< 60 mmHg

46. High-Flow Nasal Cannula (HFNC)

47. Recommended
Reading
https://dl.icdst.org/pdfs/files3/64490310a98
c6c9ef7029b2e5cbe2c0d.pdf

48. Thank You