NIV, or non-invasive ventilation, is a form of ventilation therapy that is applied non-invasively through a mask rather than an endotracheal tube. It is commonly used to treat conditions like COPD exacerbations, pulmonary edema, and respiratory failure. Key settings that must be adjusted include IPAP, EPAP, Ti min/max, trigger sensitivity, and backup rate. Modes include spontaneous, timed, and bi-level positive airway pressure. Proper mask fitting and troubleshooting issues like leaks are important for ensuring effective ventilation. Regular monitoring of parameters like ABGs, SpO2, and ventilation is needed to optimize NIV therapy.

1. NIV
Non Invasive Ventilation
Dr. Prakhar Agarwal
Resident Pulmonary Medicine
Government Medical College and Hospital Chandigarh

2. WHAT IS NIV
• NIV/NPPV (Non invasive positive pressure ventillation) is a broad term
for any ventilation therapy applied in a non invasive way e.g. via a
mask, nasal prongs or a helmet.
• Invasive ventilation on the other hand uses an endotracheal tube or a
tracheal canula.

3. INDICATIONS
• Moderate to severe dyspnea
• Respiratory rate > 25 breaths/min
• 7.25<pH<7.35
• PaO2/FiO2 < 300
• PaCO2 > 45mm Hg / 6 Kpa
• Use of accessory muscles
• Presence of paradoxical breathing
*NIV indicated if two criteria are applicable

4. CONTRAINDICATIONS
• Confused, agitated, comatose or patients with CVA
• Hemodynamic instability: uncontrolled arrythmia, very high doses of
ionotropes, recent MI
• Facial abnormalities, facial burns, trauma, anomaly
• Severe GI symptoms- Vomiting, obstructed bowel, recent GI surgery
• Copius secretion
• Conditions when NIV not effective

5. Conditions in which NIV used
Most Patients
• COPD
• Pulmonary Edema
Selected Patients
• OSA
• Cystic fibrosis
• ARDS, CAP
• Weaning of mechanical ventilation
• Immunocompromised state
• Do not intubate status
• Postoperative repiratory distress and
respiratory failure (if no ileus)
• Neuromuscular respiratory failure

6. Goals of NIV therapy
• Decrease CO2
• Improve oxygenation
• Reduce work of breathing
• Augment Tidal Volume
• Improve Sleep quality
• Reduce hospital admissions
• Reduce morbidity

7. Important Settings in NIV
To be prescribed
• EPAP
• IPAP
• Pressure Support
• Rise Time
• Fall Time
• Ti min
• Ti max
• Trigger sensitivity
• Cycle sensitivity
• Backup Rate
Other important but
often missed
• Mask type
• Tube type
• AB Filter

8. EPAP and IPAP
IPAP (Inspiratory positive airway pressure)- the pressure reached during each inspiration
cycle.
• Provides PS (Pressure Support) EPAP-IPAP
• Increases Tidal Volume
• Reduces CO2
• Improves ventillation and deceases work of breathing
EPAP (Expiratory positive airway pressure a.k.a PEEP) – the pressure reached at the end
of expiration.
• Maintains patency of upper airway
• Improves oxygenation
• Facilitates removal of CO2
• Decreases effect of intrinsic PEEP (PEEPi, also known as auto-PEEP) and increases VQ
matching

9. Machine and Patient initiation
• Machine Initiation: means the breath is initiated at pre-set time, according to the
setting for respiratory frequency.
• Patient initiation: means that the breath is initiated by the patient’s respiratory
effort, by means of a pressure or flow based trigger.
• Pressure trigger: ventilator monitors the airway pressure during the expiratory
phase. When the patient contracts its inspiratory mucles, the airway opening
pressure drops below the baseline. When this drop reaches a pressure threshold
defined by the trigger sensitivity control, the machine responds by initiating the
inspiratory phase of the respiratory cycle.
• Flow trigger: ventilator sense the gas flow. When the patient contracts their
inspiratory muscles the airflow reverses from end-expiratory or zero to
inspiratory. When the inspiratory flow generated by the patient reaches the
trigger sensitivity threshold, the machine responds by initiating inspiration.

10. Inspiratory Time (Ti)
• Ti min: the minimum time device will provide IPAP before dropping to
EPAP.
• Ti max: the maximum time device will provide IPAP before dropping
to EPAP.
• This eventually decides the I:E ratio so should be adequately titrated.
• Ti max should be limited in COPD patients so there is enough time for
exhalation.
• Ti min should be higher for restrictive patients as these patients tend
to take very feeble breaths, and they may not get adequate
oxygenation.

12. Trigger Sensitivity & Cycle sensitivity
Inspiratory Trigger Sensitivity: The amount of flow that triggers the device to
increase pressure from EPAP to IPAP.
• It determines how much flow the patient creates in order for the machine
to increase the pressure.
Cycle sensitivity or Expiratory Trigger Sensitivity (ETS): The amount of (peak
inspiratory) flow that triggers the device to decrease pressure from IPAP to
EPAP.
• It is important when trying to synchronise the ventilator with patient’s
activity.
• These indicate whether the ventilator starts or end spontaneous breath.

13. ETS can be anywhere between 5% to 80%.
In general increasing the ETS settings
results in a shorter inspiratory time, while
decreasing it results in longer inspiratory
time.
Another criterion is Ti max. this setting is
used if gas leakage is significant and the
set cycle is not reached, providing a
backup so that inspiration can be
terminated. The ventilator switches over
to exhalation when set Ti max is reached.
A typical ETS setting in a patient with a
normal lung mechanics undergoing NIV is
25%.
With obstructive patients like COPD ETS
should be set higher to increase the
expiratory time and thus avoid air trapping
and intrinsic PEEP.
Incorrect ETS settings lead to expiratory
asynchrony and may be recognised from
either delayed or premature cycling.

14. Backup rate/ Target Patient Rate
• Target Patient Rate is the rate in which you want patient to be ideally
breathing.
• Usually higher in patients of restrictive disorders.
• Backup Rate is the minimum number of breaths guaranteed by the
device per minute.
• Generally the backup rate is 3-4 breaths less than the target patient
rate- this prevents asynchrony, while ensuring adequate ventilation.

15. • The time taken by the device to increase the pressures from EPAP to
IPAP
• We can decide how quickly or slowly pressures should rise
• Keep in mind the RR, and hence available inspiratory time.
Rise Time (and Fall Time)

16. Types of Breaths
NIV ventilators are set to deliver 3 types of breaths:
• Mandatory Breath (Pressure Control Mode):
Started, Controlled and ended by the ventilator. The ventilator does all the
work
• Assisted Breath (Assisted Pressure Control Mode):
Initiated by the patient (inspiratory trigger) but controlled and ended by the
ventilator.
• Spontaneous Breath (Pressure Support Mode):
Initiated (inspiratory trigger), Controlled, and ended by the patient (expiratory
trigger); however the volume and/or pressure of the breath delivered by the
ventilator is based on patient’s demand.

17. TYPES OF MODES
• S (Spontaneous Mode)
• T (Timed Mode)
• S/T (Spontaneous/Timed mode)
• PAC (Pressure assist Control mode)
• VAPS (Volume assured Pressure support mode)
• iVAPS

18. S (Spontaneous Mode)
• The ventilator sense patients breath and triggers IPAP in response to
increase ion flow, it cycles into EPAP at the end of inspiratiom
• Breath rate determined by the patient
• Ti min and Ti max set to ensure appropriate cycling

19. T (Timed Mode)
• Fixed breath rate and fixed inspiration time is delivered as set by the
clinician regardless of the patient effort.

20. S/T (Spontaneous/Timed mode)
• Ventilator augments any breath initiated by the patient, but will also
deliver additional breaths should the patienty breath rate fall below
the clinician set backup breath rate
• Ti min and Ti max set to ensurfe appropriate cycling

21. PAC (Pressure assist Control mode)
• Inspiration time is preset in the PAC mode; the inspiration can be
triggered by the patient or time triggered at the backup breath rate
• PAC mode is the same as the S/T mode when Ti min = Ti max

22. AVAPS (Automated Volume assured Pressure
support mode)
• Pressure varies, volume remains constant.
• It combines the advantages of pressure support ventilation, such as
patient synchrony and comfort, with assurance of volume target.
• Suitable for patients with progressive lung disease as the pressure
support will adapt to the changing ventilatory needs of the patient.
• Some VAPS mode target tidal volume which might lead to the patient
experiencing episodes of hypo or hyper ventilation depending on its
respiratory rate

23. iVAPS
• iVAPS is a recent NIV mode which achieves a target alveolar
ventilation by adjusting pressure support and respiratory rate
automatically. In iVAPS the target is alveolar ventilation not the Tidal
Volume, taking into account a predicted dead space.
• Intelligent, automatic alveolar
• iVAPS is designed to maintain a preset target alveolar minute
ventilation
• Monitors delivered ventilation
• Adjusts pressure support
• Provides an intelligent backup breath

25. Auto EPAP in iVAPS
• This optional Auto EPAP feature in some machines addresses upper airway
obstructions by auto adjusting expiratory pressures according to the
severity of the event.
• Why necessary?
• EPAP should be titrated to overcome any upper airway obstruction. This
can vary night-to-night
• Can be dependent on body position
• Can change with medication and lifestyle
• Can change with weight gain and weight loss
• Airway resistance can be altered dynamically by nasal blockage,
bronchospasm, airway secretions and fall in pharyngeal tone during sleep.

27. More about AVAPS
Min PS Max PS EPAP
Obstructive 4 cm H2O 20 cm H2O 5 cm H2O
Restrictive 4 cm H2O 20 cm H2O 5 cm H2O
OHS 4 cm H2O 20 cm H2O 7 cm H2O
Normal 4 cm H2O 20 cm H2O 5 cm H2O
Treated in S/T mode
IPAP 20 cm H2O
EPAP 5 cm H2O
PS 15 cm H2O
Transition to iVAPS
Mode
Min PS: 12 cm H2O
Max PS: 20 cm H2O
Target Va
COPD <11L/min
Non-COPD <7L/min
To decrease PaCO2 by 10% increase target Va by 10%
Default value of target Va is 5.2L/min

28. AVAPS v/s S/T mode
AVAPS
Min PS and max PS
EPAP oxygenation
Auto PS
Assured average
volume
S/T mode
IPAP Ventilation
EPAP Oxygenation
Fixed PS IPAP minus
EPAP

29. When to use AVAPS
AVAPS
• Best for chronic use with changing lung compliance as in these patients
lung compliance drops over a longer period.
• AVAPS should not be used when rapid IPAP adjustments are needed to
achieve the desired Tidal volume as you should not expect to see a change
of more than 2.5cm of H2O within one minute.
Excellent results in
• OHS
• Restrictive diseases
• Neuromuscular diseases
• Chronic COPD. In

30. Initiation of NIV

31. What to monitor
• ABG
• SpO2
• Airway pressure
• Minute volume
• Frequency
• FiO2
• Spontaneous triggering and cycling
• Leak
Target Values
SpO2 > 88%; For COPD
(88-92%)
7.35 < pH < 7.45
14 < RR < 25
breaths/min
35 mm Hg < PaCO2 < 45
mm Hg
6 ml/kg < Vt < 8ml/kg

32. Types of masks
Nasal Pillows Nasal mask

33. Which Mask is better
Full Face mask Nasal masks / Nasal Pillows
Advantages Best suited for lesser co-operative patients
Better in patient with high severity of illness
Better for patients with mouth breathing
Better in edentulous patients
Generally more effective ventilation
Best suited for more co-operative patients
Better in patient with lower severity of illness
Not claustrophobic
Allows speaking, drinking coughing
Less aspiration risk with emesis
Disadvantages Claustrophobic
Hinder speaking and coughing
Risk of aspiration with emesis
More leaks possible (eg: mouth breathing or
edentulous patients)
Effectiveness limited in patients with nasal
deformities or blocked nasal passages

34. TROUBLESHOOTING
• High unintentional leak:
• Mask leak- check mask fitting
• Mouth leak- change to full face mask, use a chin strap, add heated humidification
• Poor ventilation: (increase RR, use of accessory muscles, High PaCO2, Low
Vt <6-8ml/Kg in obstructive & <8-10ml/Kg in restrictive lung disease)
• Titrate IPAP, Backup rate, Ti min and max, Rise time
• Techniques to clear secretions
• Poor Oxygenation: (Low SpO2 with good ventilation)
• Increase O2 support, increase EPAP/PEEP
• Techniques to clear secretions

35. • Complaints about speed of airflow: (air arrives too quickly or slowly or
RR 25-30)
• Titrate rise time
• Triggering Asynchronies: (Missed Trigger or Auto Trigger )
• Missed Trigger- presence of OSA or intrinsic PEEP : increase EPAP, PEEP,
increase trigger sensitivity to high or v. high
• Auto Trigger – decrese trigger sensitivity to low or v. low
• Cycling Asynchronies: (Inspiration too short or long)
• Too short- increase Ti min or use PAC mode, titrate trigger settings
• Too long- titrate Ti max and trigger settings, check mask leak
• Complaints of dryness or nasal congestion:
• Use heated humidification

37. THANK YOU