12. Non-Invasive Ventilation

Report
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
NIV
 Pressure greater than atm
applied to proximal airway
throughout resp cycle
 Greater pressure applied
during inspiration over and
above the baseline CPAP
 Splints airway

Unloads resp muscles
 Increases lung volume

Can provide complete
resp support
 Raises intrathoracic
pressures
 Does not offload resp
muscles
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 score
Mortality of 10% in NIV group as compare to 30 %
in control group
Bott et al, Lancet 1993
Risk of treatment failure in seven studies of
NPPV as an adjunct to usual medical care
3
0.17
NPPV
Usual Medical Care 0.3
2.5
6.60
2
6
0.38
0.58
0.51
1.5
1
0.63
0.5
0.51
(95% CI)
Total
2000
Plant et al
et al 2002
Dikensoy
al 1998
Celikel et
et al 1995
Brochard
1993
Bott et al
1996
Barbe et al
al 1998
Avdeev et
0
BMJ 2003;;326:1-5
NPPV
Usual
medical
care
Avdeev et al 1998
7/29
12/29
0.58 (0.27 to
1.27)
Barbe et al 1996
4/14
0/10
6.60 (0.39 to
110.32)
Bott et al 1993
5/30
13/30
0.38 (0.16 to
0.94)
Brochard et al 1995
12/43
33/42
0.36 (0.21 to
0.59)
Celikel et al 1998
1/15
6/15
0.17 (0.02 to
1.22)
Dikensoy et al 2002
4/19
7/17
0.51 (0.18 to
1.45)
Plant et al 2000
22/118
35/118
0.63 (0.39 to
1.00)
Total (95% CI)
55/268
106/261
0.51 (0.38 to
0.67)
Study
Risk ratio (fixed 95% CI)
Risk ratio
(fixed 95%
CI)
BMJ 2003;;326:1-5
Risk of treatment failure in seven studies of NPPV as an adjunct to usual medical care
3
Total (95% CI)
0.20
0.50
Plant et al 2000
1
Kramer et al 1995
0.35
Dikensoy et al 2002
0.62
Celikel et al 1998
4
Brochard et al 1995
5
Bott et al 1993
6
Barbe et al 1996
2
Avdeev et al 1998
Risk of endotracheal intubation in eight
trials of NPPV as an adjunct to usual
medical care
0.14
NPPV
Usual medical Care
0.29
0.42
0.56
0
Study
NPPV
Usual
medical
care
Avdeev et al 1998
5/29
8/29
0.62 (0.23 to 1.68)
Barbe et al 1996
0/10
0/10
Not estimable
Bott et al 1993
0/30
2/30
0.20 (0.01 to 4.0)
Brochard et al 1995
11/43
31/42
0.35 (0.20 to 0.60)
Celikel et al 1998
1/15
2/15
0.50 (0.05 to 4.94)
Dikensoy et al 2002
2/17
7/17
0.29 (0.07 to 1.18)
Kramer et al 1995
1/11
8/12
0.14 (0.02 to 0.92)
Plant et al 2000
18/118
32/118
0.56 (0.34 to 0.94)
Total (95% CI)
38/273
90/273
0.42 (0.31 to 0.59)
Risk ratio (fixed 95% CI)
BMJ 2003;;326:1-5
Risk of endotracheal intubation in eight trials of
NPPV as an adjunct to usual medical care
Risk ratio (fixed 95%
CI)
0.50
Total (95% CI)
0.33
Plant et al 2000
0
Dikensoy et al 2002
0.33
Celikel et al 1998
0.33
Brochard et al 1995
10
9
8
7
6
5
4
3
2
1
0
Bott et al 1993
0.33
Barbe et al 1996
Avdeev et al 1998
Mortality in seven studies of NPPV as an
adjunct to usual medical care
NPPV
Usual medical care
0.50
0.41
Study
NPPV
Usual
medical
care
Avdeev et al
1998
3/29
9/29
0.33 (0.10 to
1.11)
Barbe et al 1996
0/10
0/10
Not estimable
Bott et al 1993
3/30
9/30
0.33 (0.10 to
1.11)
Brochard et al
1995
4/43
12/42
0.33 (0.11 to
0.93)
Celikel et al 1998
0/15
1/15
0.33 (0.01 to
7.58)
Dikensoy et al
2002
1/17
2/17
0.50 (0.05 to
5.01)
Plant et al 2000
12/118
24/118
0.50 (0.26 to
0.95)
Total (95% CI)
23/62
57/261
0.41 (0.26 to
0.64)
Risk ratio (fixed 95% CI)
Risk ratio (fixed
95% CI)
BMJ 2003;;326:1-5
Mortality in seven studies of NPPV as an adjunct to usual medical care
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
Gender NIV setting
M:F
NIV duration
Bronchoscopi Complications
c procedure
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
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
BAL
4 in NIV
7 in O2 died of
underlying illness
No procedural
complications
Antonel Prospective
8
li et
observational
al(3)
(1996)
40 ± 14
years
Maitre
et al
(2002)
30
With CPAP15
Without
CPAP-15
58 (3578)
57 (2683)
26
13-NIV
13-O2
supplement
by venturi
mask
NIV 8:8 in
52 ± 20 both
years
groups
O2 - 57
± 10
years
CPAP-4
PSV-15 to 17
FiO2-0.9
10 minutes before
FOB and 30
minutes after the
procedure
Antonel Prospective
4
li et al
observational
(2003)
60.25
years
PSV-10 to 20
PEEP- 8 to 14
FiO2-0.7to 0.9
Before and during BAL
FOB and 30 minute
after procedure
One patient died after
48 hours due to
underlying disease
Heunks Prospective
12
et al
observational
(2010)
64.25
years
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 Prospective
al
case-control
(2010) study
NIV-80 12:3
±5
9:6
CMV80 ± 5
PSV-10 to 25
PEEP- 5
FiO2-1
Before FOB until
clinical
improvement with
gradual reduction
of PSV
BAL
None related to the
procedure
Randomized
controlled
study
Antonel Randomized
li et al
controlled
(2002) study
NIV-15
CMV-15
15:4
15:5
6:6
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 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
…
Trigger,
- leak, tightness
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
Solutions
1.
Leak
1.
Check mask fit/ strap
position/ tubings / ? Chin
strap
2.
Agitation / asynchrony
2.
Talk to patient / adjust
settings / sedation /analgesia
3.
Hypoxia
3.
Adjust ventilator / FiO2/
intubate
4.
Adjust ventilator / FiO2/
intubate
4.
Hypercarbia
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 gas
exchange and heart
respiratory rates within
first 2 hours
…
Situations where NIV is likely
to fail
Hypercapnic failure
Hypoxemic failure

GCS < 11

Diagnosis of ARDS / pneumonia

RR > 35/min

Age > 40

PH < 7.25

SBP < 90

APACHE > 29

Metabolic acidosis PH < 7.25

Asynchrony

Low PO2/ FiO2

Agitation / intolerance

Simplified APS II > 34

Failure of PO2 / FiO2 to improve
above 175 by 1st hour

Edentulous / excessive leak

No initial improvement
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

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