Non-Invasive Ventilation

Arjun Srinivasan, Mahadevan & PattabhiramanPulmonology Associates

KMCH

Agenda

Definition & mechanism of action

Indications

When, who, where, what & how ?

Technical aspects

Weaning off NIV

Complications

NONINVASIVE VENTILATION

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

CPAP vs. NIV

CPAP

Pressure greater than atm applied to proximal airway throughout resp cycle Splints airway Increases lung

volume Raises intrathoracic

pressures Does not offload resp

muscles

NIV

Greater pressure applied during inspiration over and above the baseline CPAP Unloads resp muscles Can provide complete

resp support

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

NIV

Whom to initiate ?

Acute COPD Pulmonary edema Immunocompromised patients Weaning from mechanical Neuromuscular weakness Bronchial asthma ARDS Do not intubate – pts Other indications

Chronic

What is expected of NIV ?

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

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

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 scoreMortality of 10% in NIV group as compare to 30 % in control groupBott et al, Lancet 1993

Risk of treatment failure in seven studies of NPPV as an adjunct to usual medical

care

0

0.5

1

1.5

2

2.5

3A

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Barb

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1996

Bott

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1993

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Celikel et

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Dik

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Pla

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2000

Tota

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(95%

CI)

NPPVUsual Medical Care

0.58

6.60

0.38

0.36

0.17

0.51

0.63 0.51

BMJ 2003;;326:1-5

Risk of treatment failure in seven studies of NPPV as an adjunct to usual medical care

0.63 (0.39 to 1.00)

35/11822/118Plant et al 2000

0.51 (0.38 to 0.67)

106/26155/268Total (95% CI)

0.51 (0.18 to 1.45)

7/174/19Dikensoy et al 2002

0.17 (0.02 to 1.22)

6/151/15Celikel et al 1998

0.36 (0.21 to 0.59)

33/4212/43Brochard et al 1995

0.38 (0.16 to 0.94)

13/305/30Bott et al 1993

6.60 (0.39 to 110.32)

0/104/14Barbe et al 1996

0.58 (0.27 to 1.27)

12/297/29Avdeev et al 1998

Risk ratio (fixed 95%

CI)Risk ratio (fixed 95% CI)

Usual medical

careNPPVStudy

0.63 (0.39 to 1.00)

35/11822/118Plant et al 2000

0.51 (0.38 to 0.67)

106/26155/268Total (95% CI)

0.51 (0.18 to 1.45)

7/174/19Dikensoy et al 2002

0.17 (0.02 to 1.22)

6/151/15Celikel et al 1998

0.36 (0.21 to 0.59)

33/4212/43Brochard et al 1995

0.38 (0.16 to 0.94)

13/305/30Bott et al 1993

6.60 (0.39 to 110.32)

0/104/14Barbe et al 1996

0.58 (0.27 to 1.27)

12/297/29Avdeev et al 1998

Risk ratio (fixed 95%

CI)Risk ratio (fixed 95% CI)

Usual medical

careNPPVStudy

BMJ 2003;;326:1-5

0

1

2

3

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Bott

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Celikel et

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Dik

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Kra

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Pla

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Tota

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5%

CI)

NPPVUsual medical Care

Risk of endotracheal intubation in eight trials of NPPV as an adjunct to

usual medical care

0.620.20

0.35

0.50

0.29

0.14

0.56

0.42

Risk of endotracheal intubation in eight trials of NPPV as an adjunct to usual medical care

0.56 (0.34 to 0.94)32/11818/118Plant et al 2000

0.14 (0.02 to 0.92)8/121/11Kramer et al 1995

0.42 (0.31 to 0.59)90/27338/273Total (95% CI)

0.29 (0.07 to 1.18)7/172/17Dikensoy et al 2002

0.50 (0.05 to 4.94)2/151/15Celikel et al 1998

0.35 (0.20 to 0.60)31/4211/43Brochard et al 1995

0.20 (0.01 to 4.0)2/300/30Bott et al 1993

Not estimable0/100/10Barbe et al 1996

0.62 (0.23 to 1.68)8/295/29Avdeev et al 1998

Risk ratio (fixed 95% CI)

Risk ratio (fixed 95% CI)Usual

medical care

NPPVStudy

0.56 (0.34 to 0.94)32/11818/118Plant et al 2000

0.14 (0.02 to 0.92)8/121/11Kramer et al 1995

0.42 (0.31 to 0.59)90/27338/273Total (95% CI)

0.29 (0.07 to 1.18)7/172/17Dikensoy et al 2002

0.50 (0.05 to 4.94)2/151/15Celikel et al 1998

0.35 (0.20 to 0.60)31/4211/43Brochard et al 1995

0.20 (0.01 to 4.0)2/300/30Bott et al 1993

Not estimable0/100/10Barbe et al 1996

0.62 (0.23 to 1.68)8/295/29Avdeev et al 1998

Risk ratio (fixed 95% CI)

Risk ratio (fixed 95% CI)Usual

medical care

NPPVStudy

BMJ 2003;;326:1-5

Mortality in seven studies of NPPV as an adjunct to usual medical care

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NPPVUsual medical care0.33 0

0.33 0.33 0.33

0.50

0.50

0.41

Mortality in seven studies of NPPV as an adjunct to usual medical care

0.50 (0.26 to 0.95)

24/11812/118Plant et al 2000

0.41 (0.26 to 0.64)

57/26123/62Total (95% CI)

0.50 (0.05 to 5.01)

2/171/17Dikensoy et al 2002

0.33 (0.01 to 7.58)

1/150/15Celikel et al 1998

0.33 (0.11 to 0.93)

12/424/43Brochard et al 1995

0.33 (0.10 to 1.11)

9/303/30Bott et al 1993

Not estimable0/100/10Barbe et al 1996

0.33 (0.10 to 1.11)

9/293/29Avdeev et al 1998

Risk ratio (fixed 95% CI)

Risk ratio (fixed 95% CI)Usual

medical care

NPPVStudy

0.50 (0.26 to 0.95)

24/11812/118Plant et al 2000

0.41 (0.26 to 0.64)

57/26123/62Total (95% CI)

0.50 (0.05 to 5.01)

2/171/17Dikensoy et al 2002

0.33 (0.01 to 7.58)

1/150/15Celikel et al 1998

0.33 (0.11 to 0.93)

12/424/43Brochard et al 1995

0.33 (0.10 to 1.11)

9/303/30Bott et al 1993

Not estimable0/100/10Barbe et al 1996

0.33 (0.10 to 1.11)

9/293/29Avdeev et al 1998

Risk ratio (fixed 95% CI)

Risk ratio (fixed 95% CI)Usual

medical care

NPPVStudy

BMJ 2003;;326:1-5

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 1998 -2008 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

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

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

NIV in weaning

Latest review included 16 trials involving 994 patients with COPD & mixed populations

They analysed effect on Weaning failure VAP Mortality

Effect on weaning failure

Effect on VAP

Effect on mortality

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

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

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

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

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

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

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

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

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 ?

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

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

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

NIV facilitated FOB

Patient receives NIV (10/5) by full face mask @ 100% FiO2 for 5 minutes preceding procedure

Patient’s vitals & SpO2 are continuously monitored

NIV facilitated FOB

Bronchoscope is introduced through“dual axis swivel” adapter of a catheter mount

This is done after patient is adequately oxygenated

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

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

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

Evidence…

Author (Year)

Study No. of patients

Age ± SD

GenderM:F

NIV setting NIV duration Bronchoscopic procedure

Complications

Antonelli et al(3) (1996)

Prospective observational

8 40 ± 14 years

CPAP-4PSV-17FiO2-1

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

30With CPAP-15Without CPAP-15

58 (35-78) 57 (26-83)

15:415:5

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

BAL Bronchial biopsy

Eight patients required intubation, 7 in the O2 group

and 1 in CPAP group

Antonelli et al (2002)

Randomized controlled study

2613-NIV 13-O2

supplement by venturi mask

NIV - 52 ± 20 years O2 - 57

± 10 years

8:8 in both groups

CPAP-4PSV-15 to 17FiO2-0.9

10 minutes before FOB and 30 minutes after the procedure

BAL 4 in NIV 7 in O2 died of underlying illnessNo procedural complications

Antonelli et al (2003)

Prospective observational

4 60.25 years

PSV-10 to 20PEEP- 8 to 14FiO2-0.7to 0.9

Before and during FOB and 30 minute after procedure

BAL One patient died after 48 hours due to underlying disease

Heunks et al (2010)

Prospective observational

12 64.25 years

6:6 PSV-10 PEEP- 6 FiO2-1

20 minutes before FOB until SpO2 > 92% @

FiO2 0.4

BAL Worsening hypoxemia during procedure in 1 patient requiring temporary withdrawal of FOB

Scala et al (2010)

Prospective case-control study

NIV-15CMV-15

NIV-80 ± 5CMV-80 ± 5

12:39:6

PSV-10 to 25 PEEP- 5 FiO2-1

Before FOB until clinical improvement with gradual reduction of PSV

BAL None related to the procedure

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.

AbstractRESULTS: 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 164.5 (146.3-176.3) 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.

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

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

Trouble shooting

Potential issues

1. Leak

2. Agitation / asynchrony

3. Hypoxia

4. Hypercarbia

Solutions

1. Check mask fit/ strap position/ tubings / ? Chin strap

2. Talk to patient / adjust settings / sedation /analgesia

3. Adjust ventilator / FiO2/ intubate

4. Adjust ventilator / FiO2/ intubate

Potential indicators of success in NIV

� Younger age

� Lower acuity of illness� Able to cooperate� Better neurologic score� Less air leak

� PaCO2 45 - 60 mmHg

� pH 7.10 - 7.35

� Synchronous breathing� Intact dentition� Less secretions� Better compliance� Improvements in gasexchange and heartrespiratory rates withinfirst 2 hours

Situations where NIV is likely to fail

Hypercapnic failure

GCS < 11

RR > 35/min

PH < 7.25

APACHE > 29

Asynchrony

Agitation / intolerance

Edentulous / excessive leak

No initial improvement

Hypoxemic failure

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

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

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

Complications of NIV

Principles of mechanical ventilation. 3e

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

Thank you

Questions ?