1. Non-Invasive Ventilation
Arjun Srinivasan, Mahadevan & Pattabhiraman
Pulmonology Associates
KMCH

2. Agenda Definition & mechanism of action Indications
When, who, where, what & how ?
Technical aspects
Weaning off NIV
Complications

3. NONINVASIVE VENTILATION
Non-invasive ventilation (NIV) refers to a form of assisted ventilation that involves provision of ventilatory support without endotracheal intubation (ETI)

4. CPAP vs. NIV
CPAP
NIV
Pressure greater than atm applied to proximal airway throughout resp cycle
Splints airway
Increases lung volume
Raises intrathoracic pressures
Does not offload resp muscles
Greater pressure applied during inspiration over and above the baseline CPAP
Unloads resp muscles
Can provide complete resp support

5. NIV – how it works Decreasing work of breathing
Off loading of resp muscles & decreasing fatigue
Preventing wide swings in intrathoracic pressure
Decreasing afterload to heart
Preventing complications of IMV
Intubation & MV
Loss of airway defenses
Post extubation issues

6. NIV Whom to initiate ? Acute Chronic COPD Pulmonary edema
Immunocompromised patients
Weaning from mechanical
Neuromuscular weakness
Bronchial asthma
ARDS
Do not intubate – pts
Other indications
Chronic

7. What is expected of NIV ?

8. NIV in COPD exacerbation
COPD exacerbation is a perfect indication for NIV use
Excellent candidates for partial respiratory support
Offloads respiratory muscles & prevents dynamic hyperinflation
Gives time for the bronchodilators & steroids to take effect
Supports till balance of respiratory system is restored

9. First study on COPD exacerbation
Pressure support ventilation by face mask leads to:
Reduced need for intubation
Duration of mechanical ventilation
Duration of ICU stay
LIMITATIONS OF STUDY
Used historical controls
Not randomized controlled trial
Bochard et al., 1990 NEJM

10. First RCT
Compared NIV (n =30)with conventional therapy (n = 30):Equal number received bronchodilators, corticosteroids and antibiotics therapy
Within first hour
NIV patients had greater improvement in pCO2 and dyspnea score Mortality of 10% in NIV group as compare to 30 % in control group
Bott et al, Lancet 1993

11. Risk of treatment failure in seven studies of NPPV as an adjunct to usual medical care
0.5 1
1.5 2
2.5 3
Avdeev et
al 1998
Barbe et al
1996
Bott et al
1993
Brochard
et al 1995
Celikel et
Dikensoy
et al 2002
Plant et al
2000
Total
(95% CI)
NPPV
Usual Medical Care
0.17
0.36
6.60
0.38
0.58
0.51
0.63
0.51
BMJ 2003;;326:1-5

12. BMJ 2003;;326:1-5
Risk of treatment failure in seven studies of NPPV as an adjunct to usual medical care

13. Risk of endotracheal intubation in eight trials of NPPV as an adjunct to usual medical care
0.14 1 2 3 4 5 6
Avdeev et al 1998
Barbe et al 1996
Bott et al 1993
Brochard et al 1995
Celikel et al 1998
Dikensoy et al 2002
Kramer et al 1995
Plant et al 2000
Total (95% CI)
NPPV
Usual medical Care
0.29
0.35
0.42
0.62
0.50
0.20
0.56

14. BMJ 2003;;326:1-5
Risk of endotracheal intubation in eight trials of NPPV as an adjunct to usual medical care

15. Mortality in seven studies of NPPV as an adjunct to usual medical care
0.33 1 2 3 4 5 6 7 8 9 10
Avdeev et al 1998
Barbe et al 1996
Bott et al 1993
Brochard et al 1995
Celikel et al 1998
Dikensoy et al 2002
Plant et al 2000
Total (95% CI)
0.50
0.33
0.33
0.33
0.50
0.41

16. Mortality in seven studies of NPPV as an adjunct to usual medical care
BMJ 2003;;326:1-5
Mortality in seven studies of NPPV as an adjunct to usual medical care

17. Role of NIV in COPD exacerbation
Established beyond doubt that NIV decreases
Failure
Intubation (NNT 4)
Mortality (NNT 10)
Chandra et al. analyzed healthcare utilization between and concluded that patients who get intubated after failed NIV had higher mortality
Increasing use of NIV in difficult to ventilate patients
Continuation of NIV despite lack of early improvement

18. NIV in cardiogenic pulmonary edema
Robust data supporting use of NIV in CPE
Cochrane review of 21 trials and 1071 subjects showed NIV
Decreases intubation (NNT 8)
Decreases in hospital mortality (NNT 13)
Does not increase risk of MI
Winck et al, reviewed 7 studies comparing NIV vs. CPAP and showed both were equally efficient even in patients with hypercapnea

19. NIV in extubation
NIV as a tool for facilitating extubation and weaning off ventilator
NIV post extubation for preventing respiratory failure for patients at risk
NIV as a treatment for established extubation failure

20. NIV in weaning
Latest review included 16 trials involving 994 patients with COPD & mixed populations
They analysed effect on
Weaning failure
VAP
Mortality

21. Effect on weaning failure

22. Effect on VAP

23. Effect on mortality

24. NIV for preventing weaning failure in at risk group
Patients of hypercapneic respiratory failure including COPD, neuromuscular dis orders
NIV post extubation as per protocol to prevent weaning failure
Studies have shown significant benefit with NIV in these sub- groups

25. NIV in established extubation failure
2 trials till date have looked at NIV in established extubation failure
Both have not shown any benefit in
Re intubation rate
ICU mortality

26. NIV in post operative patients
Main aim in post operative patients is
Prevent acute respiratory failure
Treat acute respiratory failure and prevent intubation
29 studies identified in a recent review
Significant heterogeneity in the type of surgery, patient co morbidities & outcome measurements
Take home point is despite lack of RCT NIV improved blood gas & prevents hypoxemia in most cases

27. Summarizing role in weaning
Definite role in weaning COPD patients
Preventing re-intubation in high risk group
No evidence to support its use in established weaning failure
Should be considered in post operative period for preventing & treating respiratory failure

28. Immunocompromised patients
NIV plays a vital role in management of these patients
Intubation is associated with significant morbidity & mortality
2 RCTs & several observational studies have been consistent in demonstrating NIV
Improves oxygenation
Reduces intubation
Reduces mortality

29. NIV in ARDS Area of intense debate & no consensus
Studies & systematic reviews have shown
May decrease intubation rates, ICU stay in select sub-groups who show early response
High rates of failure
Disturbingly patients who get intubated after failed NIV have higher mortality
Use with caution / not at all
When in doubt, intubate

30. NIV in asthma Data is scarce in Asthma
Early studies showed no clear benefit
Recent study from PGI showed better lung function with lower bronchodilator requirements with NIV
Likely to remain this way as with modern therapy established respiratory failure requiring ventilatory support is very rare

31. NIV in do not intubate
NIV is being increasingly used in these patients especially in wards
Recent studies have shown
Up to 43 % of these patients survive to discharge
Depends on primary etiology
COPD & CCF fare better
Better sensorium / ability to clear secretions have better outcome
Post exubation failure, hypoxemic respiratory failure & end stage cancers patients fare poorly

32. NIV in DNI- guidelines Goals
NIV in patients without any restrictions to other life supporting treatments
NIV in patients refusing endotracheal intubation
NIV as the only support (TLC group)
Need to discuss goals clearly & get consent from relatives
Unclear issues
Whether actually provides comfort ? Or
Just prolongs the dying process ?

33. NIV in chest trauma Recent systematic review of 9 studies showed in
In blunt trauma chest without ALI, NIV
Reduces intubation
Hypoxemia
ICU stay
Mortality
With established ALI
Controversial with no good data

34. NIV for pre-oxygenation
2 RCTs have evaluated 3-5 mins of NIV as compared to routine preoxygenation before intubation
NIV associated with
Higher SpO2 immediately after & at 5 mins
Higher lung volumes
Especially in morbidly obese patients

35. NIV in OHS
Acute exacerbation patients fare similarly if not better than COPD patients with hypercapneic respiratory failure
They they get intubated, will need NIV immediately post extubation
These patients need continuance of care with home NIV
Can have late NIV failures because of non compliance

36. NIV facilitated FOB
Patient receives NIV (10/5) by full face 100% FiO2 for 5 minutes preceding procedure
Patient’s vitals & SpO2 are continuously monitored

37. NIV facilitated FOB
Bronchoscope is introduced through“dual axis swivel” adapter of a catheter mount
This is done after patient is adequately oxygenated

38. NIV facilitated FOB
2 % lidocaine gel for lubrication & local anesthesia
Mask is replaced after nasal entry of bronchoscope
Tight apposition to ensure no leak
Vitals are continuously monitored

39. NIV facilitated FOB
BAL - wedging scope against approprite segment (3-5 alliquots of ~ 50 ml NS)
TBLB – after decreasing CPAP to 0 & PS = 10 cms
NIV continued for 30 mins post procedure

40. Mechanism of action of NIV
Splinting of upper airway & increasing cross sectional area
Counteracting the PEEPi created due to obstruction caused by bronchoscope
Ability to provide FiO2 of 1
Recruitment of collapsed alveoli- thereby reducing shunt fraction & increasing FRC
Decreases WOB

41. Evidence…

42. Author (Year)
Study
No. of patients
Age ± SD
Gender
M:F
NIV setting
NIV duration
Bronchoscopic procedure
Complications
Antonelli et al(3) (1996)
Prospective observational 8
40 ± 14 years
CPAP-4
PSV-17
FiO2-1
10 minutes before FOB and 90 minutes after the procedure
BAL
Two patients died after 5 & 7 days of FOB due to underlying disease
Maitre et al (2002)
Randomized controlled study 30
With CPAP-15
Without CPAP-15
58 (35-78)
57 (26-83)
15:4
15:5
CPAP titrated in incremental steps of 2.5 cm H2O up to 7.5 cm
5 minutes before FOB and 30 minutes after the procedure
Bronchial biopsy
Eight patients required intubation, 7 in the O2 group and 1 in CPAP group
Antonelli et al (2002) 26
13-NIV
13-O2 supplement by venturi mask
NIV - 52 ± 20 years
O ± 10 years
8:8 in both groups
PSV-15 to 17
FiO2-0.9
10 minutes before FOB and 30 minutes after the procedure
4 in NIV
7 in O2 died of underlying illness
No procedural complications
Antonelli et al (2003) 4
60.25 years
PSV-10 to 20
PEEP- 8 to 14
FiO2-0.7to 0.9
Before and during FOB and 30 minute after procedure
One patient died after 48 hours due to underlying disease
Heunks et al (2010) 12
64.25 years
6:6
PSV-10 PEEP- 6
20 minutes before FOB until SpO2 > FiO2 0.4
Worsening hypoxemia during procedure in 1 patient requiring temporary withdrawal of FOB
Scala et al (2010)
Prospective case-control study
NIV-15
CMV-15
NIV-80 ± 5
CMV-80 ± 5
12:3
9:6
PSV-10 to 25 PEEP- 5
Before FOB until clinical improvement with gradual reduction of PSV
None related to the procedure

43. Respir Care. 2012 Mar 13. [Epub ahead of print]
Bronchoscopic Lung Biopsy Using Noninvasive Ventilatory Support: Case Series and Review of Literature of NIV-assisted Bronchoscopy.
Agarwal R, Khan A, Aggarwal AN, Gupta D.
Abstract
RESULTS:
Six patients with a mean (SD) age of 44.5 (11.6) years were included in the study. The median (IQR) PaO₂/FiO₂ ratio prior to lung biopsy was ( ) and the median (IQR) IPAP/EPAP used was 14 (12-15)/5 cm H₂O. FOB was well tolerated and all patients maintained SpO₂ >92% during the procedure. One patient required endotracheal intubation due to hemoptysis. A definite diagnosis was obtained in five of the six patients. A repeat procedure was performed in one patient, which again yielded no diagnosis. No other periprocedural complications were encountered.
CONCLUSIONS:
NIV-assisted BLB is a novel method for obtaining diagnosis in hypoxemic patients with diffuse lung infiltrates. However, this approach should be reserved for centers with extensive experience in NIV. More studies are required to define the utility of this approach.

44. Monitoring during NIV Subjective and objective parameters
First 2hrs - intense monitoring
Next 8hrs - close monitoring…
There after - routine monitoring
Even if parameters were borderline at start of NIV, early change / improvement predicts success of NIV
This is the most important aspect of NIV
First few hours predict the outcome of the patient

45. Monitoring during NIV
… Look at patient, ventilator, interface, bed side monitor, ABG … Patient - Comfort, conscious level
Chest expansion
Accessory muscles
Synchrony
… Interfaces - leak, tightness
… Trigger, volume delivered, cycling … HR, RR, SpO2, BP
… ABG - pCO2, pH, pO2
at base line, 1-2hrs after, then based on response

46. Trouble shooting Potential issues Solutions
Leak
Agitation / asynchrony
Hypoxia
Hypercarbia
Check mask fit/ strap position/ tubings / ? Chin strap
Talk to patient / adjust settings / sedation /analgesia
Adjust ventilator / FiO2/ intubate

47. Potential indicators of success in NIV
… Synchronous breathing … Intact dentition
… Younger age
… Lower acuity of illness … Able to cooperate
… Less secretions … Better compliance … Improvements in gas
… Better neurologic score … Less air leak
… PaCO mmHg … pH
exchange and heart
respiratory rates within first 2 hours

48. Situations where NIV is likely to fail
Hypercapnic failure
Hypoxemic failure
GCS < 11
RR > 35/min
PH < 7.25
APACHE > 29
Asynchrony
Agitation / intolerance
Edentulous / excessive leak
No initial improvement
Diagnosis of ARDS / pneumonia
Age > 40
SBP < 90
Metabolic acidosis PH < 7.25
Low PO2/ FiO2
Simplified APS II > 34
Failure of PO2 / FiO2 to improve above 175 by 1st hour

49. Weaning patients from NIV
No specific protocol
Pts of COPD would require at least 24 hours to stabilise
NIV is usually removed as per patient’s request for feeding/facial hygiene
Re – attached as deemed necessary
Attempt gradual decrease in IPAP / EPAP & discontinue when patient tolerates

50. Complications of NIV Failure is the most serious complication
Most dreaded complication is failure to recognize NIV failure early leading to delay in intubation
Studies have shown that this can lead to increased mortality especially when used in situations where NIV is used without strong evidence

51. Complications of NIV
Principles of mechanical ventilation. 3e

52. Summary & conclusions
NIV is an important tool in the hands of RT & intensivist
Provides a level of respiratory support in emergency / wards unimaginable otherwise
Has changed the way we manage COPD exacerbations
Needs careful monitoring during initial hours
A tool which needs to be used wisely for us to reap the benefits

53. Thank you
Questions ?