THIS IS THE BASIC POINTS REGARDING NIV, THIS IS COMPILED AND ARRANGED FROM DIFFERENT BOOKS, JOURNALS AND PPTs. The author is grateful to the teachers and authors of pulmonology and critical care.

1. NIV: Interesting facts
Dr. Chandan Kumar Sheet
MD (Pulmonary Medicine)
Pulmonologist, Calcutta Heart Clinic & Hospital

2. Points to be covered
 NIV Wave forms
 NIV Interface
 Monitoring
 Newer modes of NIV
 Weaning from NIV
 New trends of NIV use
 Miscellaneous issues

3. NIV Terminology
 PPV-
Positive pressure ventilation
 BIPAP-
Bi-level positive airway pressure
 CPAP –
Continuous positive airway pressure
 EPAP-
Expiratory positive airway pressure
 IPAP-
Inspiratory positive airway pressure
 PEEP-
Positive end expiratory pressure
 RATE-
- Number of breaths per minute
- Determined by the patient in NIV

4. NIV Terminology
 RISE TIME-
- Time taken to reach to IPAP from
EPAP
- This is set for patient comfort
 INSPIRATORY TIME-
How long BIPAP unit stays at IPAP
 PRESSURE SUPPORT-
- Difference between IPAP & EPAP
- This is the amount of assistance applied
to the inspired breath.
- Determines the tidal volume
- Higher the pressure support larger the
breath

5. NIV Terminology
 TRIGGER-
- Point where the BIPAP unit transitions from EPAP to the IPAP
- Initiation of inspiration or initiation of IPAP in BIPAP
- In BIPAP initiation of inspiration is patient trigger
 CYCLE-
- Point where the BIPAP unit transit from IPAP to EPAP
- Beginning of EPAP & end of inspiration
 SENSITIVITY –
- Refers to triggering & cycling of the device
- Sense inspiratory effort to trigger IPAP

6. BIPAP Waveform

7. Titration – Set Rise Time
 Rise time- Time from EPAP to IPAP
 Obstructive airway disease- Short rise time
 Restrictive disease- Prolonged rise time
 CAUTION- Long rise time with high respiratory rate not compatible

8. Most NIV devices are pressure cycled
 Most NIV ventilators are pressure cycled
 NIV apply positive pressure to the airways until a preset pressure limit is
reached.
 Tidal volume is adjusted by increasing or decreasing the pressure limit.
 Although peak pressure will remain constant, the volume will change as lung
compliance and/or airway resistance change.

9. Pressure cycled

10. A typical breath

11. Inspiratory Time
 This is very important and is often missed in the initial settings
 This decides the I:E ratio
 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 patient tend to take
very feeble breaths, and they may not
get adequate oxygenation

12. Setting Ti times –
ready reckoner

13. Trigger sensitivity
 (Inspiratory) Trigger is an input required by the device to increase the pressure
from EPAP to IPAP
 The input could be flow, pressure, volume or time
 Usually, bi-level ventilators trigger on flow, as it is more sensitive
 Trigger Sensitivity defines how much flow should the patient create to increase the
pressure

14. Flow trigger- Most common

15. Trigger settings are flow sensitive
5 Trigger sensitivities
Very High Quick to trigger 2.4L/min
High Sensitive 4 L/min
Med Default 6 L/min
Low Less sensitive 10 L/min
Very Low Slow to trigger 15 L/min
Very High
Very
Low

16. Issues with Trigger
 Auto Trigger
 Failure to trigger

17. Auto triggering
 Trigger too sensitive
 Recoil of tubing
 Leak
- Mimics inspiratory flow
- Drags EPAP below trigger threshold
 Reduce Trigger Sensitivity to overcome this problem

18. Failure to trigger
 The most common causes are:
- Intrinsic PEEP in case of COPD patients
- Upper airway obstruction (in all patients)
 Increasing the EPAP almost always solves the failure to trigger problem
 In case the problem still persists, the trigger sensitivity can be increased

19. Cycle sensitivity
 Cycle (Expiratory Trigger) sensitivity
is a trigger for the device to drop the
pressure from IPAP to EPAP

20. Very High Quick to cycle 50 % of
peak flow
High Sensitive 35%
Med Default 25%
Low Less sensitive 15%
Very Low Slow to cycle 8%
Wide cycle sensitivity
Very High
Very Low
5 cycle sensitivities
• It is recommended to
keep a higher cycle sensitivity for COPD patients
keep a lower sensitivity for restrictive patients

21. NIPPV Interface
 Nasal masks
 Oronasal mask
 Full Facemask
 NIV Helmet
 Nasal Pillow

22. Nasal MaskADVANTAGES
 Less risk of aspiration
 Enhanced secretion clearance
 Less Claustrophobia
 Easier speech
 Less dead space
 Best suited for cooperative patients
 Better in patient with less severity of illness
DISADVANTAGES
 Mouth leak
 Less effectiveness with nasal obstruction
 Nasal irritation & rhinorrhea
 Mouth dryness

23. Oronasal mask
ADVANTAGE
 Good seal
 More effective ventilation
 Best suited for less cooperative patients
 Better for higher severity of disease
 Better for mouth breather or purse lip breathing
 Preferred in edentulous patients
DISADVANTAGE
 Claustrophobia
 Regurgitation &aspiration
 Asphyxia

24. Nasal pillows
 More commonly used in CPAP therapy
 Consists 2 small cushions that fit within the nostrils.
 They are an alternative to nasal, oro-nasal,
or full face masks.
 Since this interface has
lower pressure range (3-20 Cm H2O),
nasal pillows are not as effective when used
in the BIPAP.

25. Full Facemask
 Covers almost the entire face
 Easy to fit
 Less air leaks as covers nasal bridge & mouth
 No pressure sore around nose & mouth
 Edentulous patients
 Mouth breathers
 Patient with facial abnormality

26. NIV HELMET

27. Monitoring of NIV

28. Monitoring
 PARAMETERS
 Monitoring is important not only for optimizing ventilator setting, but
also to warn against impending catastrophe if NIV falls
 Monitoring includes
1)Subjective Response
2)Physiological Response
3)Gas exchange Response

29. Monitoring
 SUBJECTIVE RESPONSE
Smooth adaptation of the patient to the ventilator
Alleviation of symptoms like dyspnea
Improved tolerance

30. Monitoring
 Physiological Response
 Simple vital signs should show an improvement.
 Assess - chest wall movement,
- heart rate
- respiratory rate
- BP
- mental status &
- patient coordination with ventilator

31. Monitoring
Gas exchange response
 Pulse oxymetry oxygen saturation should be maintained >92%.
 ABG should be cheeked at baseline & at 1-4 hours
 Improvement in ABG particularly in PH ,after a short period of NIV
predicts successful outcomes

32. Monitoring
Others :Clinical monitoring
 Exhaled tidal volume and flow/pressure
 waveforms
 Continuous ECG
 Severe neurologic deterioration
 Main indications for rapid endotracheal intubation

33. Problems & Complications of NIV

34. Problems & Complications
Related to Air Pressure & Flow
 Pressure sore over nose &
forehead
 Air pressure in nose & sinus
causes pain,
burning, coldness or
ear pain (10-30%)
 Nasal congestion (20-50%)
 Nasal dryness (10-20%)
 Oral dryness
 Gastric distention
 Eye irritation

35. Problems & Complications
Major Complications
Infrequent (5%)
 Delay in intubation
 Major desaturation & cardiac
arrest in hypoxemic
respiratory failure
 Aspiration pneumonia (5%)
 Hypotension
 Pneumothorax

36. Increased headstraps tension to
reduce air leaks
Air leaks
Skin
breakdown

37. Skin ulceration

38. Not always occur where
they are expected!!!
Pressure skin ulceration

39. Headstraps tension
Avoid air leaks
Avoid skin
breakdown

40. Newer modes of NIV

41.  Volume assured pressure support (VAPS) modes combine the advantages of
pressure support ventilation, such as patient-synchrony and comfort, with the
assurance of a volume target.
 VAPS modes are particularly suitable for patients with progressive lung pathologies,
as the pressure support will adapt to the changing ventilatory needs of the patient
 iVAPS (Intelligent Volume Assured Pressure Support) mode targets Minute Alveolar
Ventilation.
Volume Assured Pressure Support (VAPS)

42. Adaptive servo‐ventilation
• Specifically to treat central sleep apnea (CSA)
• Designed to vary support according to a patient’s individual breathing
rate
• Automatically calculates a target ventilation
• Adjusts the pressure support to achieve it

43. Assisted PCV ( APCV)
 This is very similar to the assist control mode in invasive ventilation
 This is very useful in patients who are weaned off from invasive ventilation or who
are recovering
 This mode allows the patient to trigger the ventilator, while ensuring the breaths
provided are of the same length
 When the patient starts to improve triggering on the PAC mode, they may be
moved to the ST mode

44. Weaning from NIV
 Weaning strategy
• Continue NIV for 16 hours on day 2
• Continue NIV for 12 hours on day 3 including 6–8 hours overnight use
• Discontinue NIV on day 4, unless continuation is clinically indicate

45. New Trends of NIV use

46. NIV in Difficult Weaning
 NIV is effective in avoiding respiratory failure after extubation
 NIV prevent reintubation after weaning from invasive mechanical ventilation in an acute
respiratory failure
NIV to Manage Extubation Failure
 • Perform NIV application immediately after extubation.
 • Closely monitor the success of the NIV treatment.
 • Do not use NIV to treat post- extubation failure.

47.  Restrictive Thoracic Disorders
 Chest wall disorders
 Obesity Hypoventilation
 Progressive Neuromuscular disorders
 Spinal Cord Injury
 Hypercapnic/non-hypercapnic Central Apnoea
 Chronic Stable COPD
 Obstructive sleep apnoea
 Cystic Fibrosis, Bronchiectasis, Post-tubercular lung
NIV in Chronic care setting
 Goal of NIV in Chronic CARE
- Relieve or improve symptoms
- Enhance quality of life
- Increase survival
- Improve mobility

48. Conditions mode
chronic respiratory failure in restrictive thoracic disorders who can protect
their airways
NIV
OSA CPAP
nocturnal desaturation and hypoventilation NIV
Symptomatic restrictive thoracic disease with severe pulmonary
dysfunction VC <50%
NIV
moderate to severe OSA not responding to CPAP NIV
severe symptomatic stable COPD despite optimal treatment NIV
COPD-OSA / OHS NIV

49. Miscellaneous issues

50. Sedation during NIV
 Ideally, before considering analgo-sedation, all the other nonpharmacologic measures should
be applied to improve NIV tolerance
 dexmedetomidine, a new a2-adrenoreceptor agonist, and a sedative, anxiolytic, analgesic
agent has been widely used.
 Midazolam iv can also be used

51. Leak compensation
 Flow sensors in the NIV continuously monitor and adjust flow (variable up to 180 L/min)
based on the set pressure, the patient’s inspiratory and expiratory efforts, and leak.
 compensation for leaks makes it easier for the patient
PILBEAM’S mechanical ventilation: 5th edition ,J.M. Cairo, phd, RRT, FAARC
Humidification Issues During NIV
 Passover heated humidifiers should be used to treat or prevent nasal congestion and
improve patient comfort.
 Bubble humidifier and heat-moisture exchangers increase airway resistance and will
increase inspiratory WOB

52. PILBEAM’S mechanical ventilation: 5th edition ,J.M. Cairo, phd, RRT, FAARC
Oxygen delivery
 FIO2 can vary and is affected by four factors:
1. Oxygen flow rate
2. Type of leak port in the system
3. Site where oxygen is bled into the circuit
Max FiO2 achieved
- If leak port is in the circuit, the oxygen is blend into the patient’s mask
- If leak port is in the mask, the oxygen is blend into the circuit at the machine outlet.
lowest FiO2
- leak port is in the mask and oxygen is bled into the mask.
4. IPAP and EPAP-Lower IPAP and EPAP levels also yield higher oxygen concentrations.

53. CO2-Rebreathing
 CO2-Rebreathing is a concern with any NIV with single-circuit gas-delivery system
because exhalation occurs through the intentional leak port and depends on the
continuous flow of gas in the circuit.
 If gas flow is inadequate, exhaled gases not be adequately flushed from the system
and the patient may rebreathe exhaled CO2.
 flow of gas through the leak port depends on the EPAP I:E
 At low EPAP settings (<4 cm H2O) and with fast respiratory rates, flow may not be
adequate to flush CO2 from the circuit.
 EPAP of 4 cm H2O or higher improves continuous flow of gas through the system and
minimizes CO2 rebreathing
PILBEAM’S mechanical ventilation: 5th edition ,J.M. Cairo, phd, RRT, FAARC

54. Aerosol delivery in NIV
 Patients may be removed from the NIV and given aerosolized
medications via nebulizer or MDI + Spacer, but this may cause rapid
deterioration of the patient’s condition.
 Bronchodilators given inline with the NIV single-limb circuit by either a
nebulizer or MDI with a spacer are effective
 Factors Affecting Aerosol Delivery During NIV
1. Presence or absence of a humidifier in the circuit
2. Position of the leak port
3. Synchronization of MDI actuation with inspiration
4. IPAP and EPAP levels
5. Volume of the mask

55.  If the leak port in the mask, aerosol delivery from an MDI is more
efficient than from a nebulizer
 Increased aerosol delivery is also more likely when using high
inspiratory pressures and low expiratory pressures
 Aerosol delivery to the lower airways is less effective when
administered through a humidified circuit
PILBEAM’S mechanical ventilation: 5th edition ,J.M. Cairo, phd, RRT, FAARC

56. Thank You..