Non-Invasive Ventilation

Επεμβαηικός και μη επεμβαηικός
μητανικός αεριζμός ζηη ΧΑΠ
Θεόδωρος Βαζιλακόποσλος
Αναπληρωηής Καθηγηηής
Ενηαηικής Θεραπείας-Πνεσμονολογίας
Εθνικό και Καποδιζηριακό Πανεπιζηημίο Αθηνών
Νοζοκομείο «ο Εσαγγελιζμός»

► Pathophysiology
Outline
► Non invasive ventilation during exacerbations to
avoid intubation
► Controlled mechanical ventilation
► Partial support ventilation
• Ventilator triggering
• Wasted efforts
► Weaning
► Non Invasive Ventilation after weaning
• Spontaneous breathing trial failure
• Post extubation

Pathophysiology
Barnes, P. J. N Engl J Med 2000;343:269-280

Flow Limitation
Hyperinflation

IRV
IRV
Tidal breathing in COPD
V T
V T
Normal
COPD
ERV
ERV
Trapped gas

ERV
IRV
Normal
Hyperinflation
Static Hyperinflation
Dynamic
Hyperinflation
IC
V T
RV
Gas Trapping in resting conditions
Gas Trapping due to exercise

Φυσιολογική αναπνοή

Αναπνοή στη ΧΑΠ

600 ml
PEEPi
600 ml

Flow
Pes
W elastic
W resistive
W PEEPi
P-V curve
reduction bronchial caliber

Decreased zone Apposition
Lower rib retraction

Length Tension Relationship:
Diaphragmatic Weakness

Imbalance Load / Neuromuscular Capacity
Vassilakopoulos T et al Eur Respir J 1996;9:2383-2400

Non-invasive ventilation
during exacerbations to
avoid intubation

700
600
500
400
300
200
100
0
-100
PTPdi/min (cmH20 x s/min)
i-PSV n-PSV T-piece S.B.
*
*

% of patients
Intubation rate in patients with acute
exacerbation of COPD treated with and
without NIPPV
80
73 74
70
60
50
40
30
20
10
31
n=16 n=15
26
n=43 n=42
NIPPV
Control
0
Kramer et al 1995 Brochard et al 1995

Hospital stay (days) of patients with acute
exacerbation of COPD treated with and without
NIPPV
80
70
60
50
40
30
20
10
0
*
NIPPV
Control
Brochard et al. NEJM 1995;333:817

% of patients
In-hospital mortality (%) in patients with
acute exacerbation of COPD treated with
and without NIPPV
35
30
30 29
25
20
15
10
5
0
10 9
n=30 n=30
n=43 n=42
Bott et al 1993 Brochard et al 1995
NIPPV
Control

% of patients
Early use of NIPPV for acute exacerbation of
COPD on general wards
30
27
25
20
15
10
15
10
20
NIPPV
Control
5
n=118 n=118 n=118 n=118
0
Need for intubation
In-hospital mortality
Plant et al. Lancet 2000;355:1931

NIV in hypercapnic encephalopathy
Scala et al, Intensive Care Med 2007;33:2101-8

Helmet worsens patient-ventilator interaction in COPD
Navalesi P et al, Intensive Care Med 2007;33:74-81

Controlled mechanical
ventilation

Mechanical Ventilation
►Volume Control
• Tidal Volume 520 ml
• Respiratory Rate = 16 breaths/min
• TI/TT = 0,25
• PEEP = 0-5 cmH2O
• FiO2 = 50%

Pressure (cmH 2 O)
Flow (l/sec)
1.5
1
0.5
Dynamic hyperinflation
0
-1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4
-0.5
-1
-1.5
60
Slope increase
End expiratory flow
50
40
Over-distension
30
20
10
0
-1 -0.5 0
-10
0.5 1 1.5 2 2.5 3 3.5 4
Time (sec)

Assessment of mechanics
Ppeak
Pplateau
PEEPi
End expiratory occlusion
Rrs = (Ppeak-Pplateau)/V’

When PEEPi is present during CMV
► Hemodynamic
compromise
► Overdistension with
risk of barotrauma
► Reduce f
► Reduce VT
► Increase inspiratory
flow to prolong TE

Partial Support Modes

Ventilator triggering

Ptr

Aslanian P, AJRCCM 1998;157:135-43

Partitioning of pressure time product during
flow and pressure triggering
9
Pressure Support
9
Assist control
8
8
7
7
6
5
4
3
PTPes
PTPtr
PTPpost
PTPpeepi
6
5
4
3
PTPes
PTPtr
PTPpost
PTPpeepi
2
2
1
1
0
PT
FT
0
PT
FT
Aslanian P, AJRCCM 1998;157:135-43

Paw (cmH 2 O)
Flow (l/sec)
0.8
0.6
0.4
0.2
0
-2
-0.2
3 8 13 18
-0.4
-0.6
-0.8
35
30
25
20
15
10
5
0
-2
-5
3 8 13 18
Fr = 12 b/min
Time (sec)
5 sec

Pes (cmH 2 O)
Paw (cmH 2 O)
Flow (l/sec)
0,8
0,6
0,4
0,2
0
-2
-0,2
3 8 13 18
-0,4
-0,6
-0,8
35
30
25
20
15
10
5
0
-2
-5
3 8 13 18
20
15
10
5
0
-2 3 8 13 18
-5
Fr = 33 b/min
Time (sec)
5 sec
Georgopoulos D

Ptr

Wasted effort
PEEPi
Ptr
Dynamic
Hyperinflation
Vrel

Ineffective efforts increase as the level of
ventilator support increases
Leung P, AJRCCM 1997;155:1940-48

Ineffective efforts decrease as
expiratory time increases
ACV
Tidal
Volume
constant
Increased
Flow
Increased
Expiratory
time
Kondili E, BJA
2003;91:106-19

Ptr

Factors predisposing to ineffective efforts
►The level of ventilator assistance
►Large tidal volume of the preceding breath
►Short expiratory time
►PEEPi

Pes (cmH 2 O)
Paw (cmH 2 O)
Flow (l/sec)
0.8
0.6
0.4
0.2
0
-2
-0.2
3 8 13 18
-0.4
-0.6
-0.8
35
30
25
20
15
10
5
0
-2
-5
3 8 13 18
20
15
10
5
0
-2 3 8 13 18
-5
Time (sec)
5 sec

Pes (cmH 2 O)
Flow (l/sec)
0,8
0,6
0,4
0,2
0
-0,2
-0,4
-0,6
-0,8
0 1 2 3 4 5 6
14
12
10
8
6
4
2
0
-2
-4
0 1 2 3 4 5 6
Time (sec)
5 sec
Georgopoulos D

Wasted efforts reduction during pressure support
Cycling off criterion
increased
in steps of 10%
Thille et al Intensive Care
Med 2008;34:1477-86
Gradual reduction
of PS level-steps of 2 cmH 2 0

Addition of external PEEP
Ptr
PEEP external

Chao et al, Chest 1997;112:1592-9
Asynchrony between patient – ventilator
► Presence of Dynamic Hyperinflation and PEEPi.
Apply external PEEP (~ 5 cmH 2 O)

Weaning

Pressure Support vs T-piece weaning in COPD
COPD Screened
77 patients
Excluded
2
Eligible T-tube trial
75
Trial Success
23 (31%)
Trial Failure
52 (69%)
T-tube
26
PS
26
Successful Weaning
20 (77%)
Successful Weaning
19 (73%)
Failed Weaning
6 (23%)
Failed Weaning
7 (27%)
Vitacca et al. Am J Respir Crit Care 2001; 164: 225

PSV
T-piece
AJRCCM 2001;164:225-230.

Non Invasive Ventilation as weaning technique
in COPD patients who fail SBT after 2 days of MV
NIV
Nava et al. Ann Intern Med 1998;128:721

% of patients
60 days mortality (%) in patients with
acute exacerbation of COPD
using NIPPV as a weaning technique
40
35
30
28
*
25
20
15
10
5
0
8
NIPPV
Control
Nava et al. Ann Intern Med 1998;128:721

Non Invasive Ventilation during persistent
(3 days) spontaneous breathing trial failure
NIV
NIV
COPD 25/43 patients
Ferrer et al. Am J Respir Crit Care Med 2003;168:70-76

Non-Invasive Ventilation
(n.114)
Conventional Therapy
(n.107)
Absolute Risk Difference
Relative Risk (95% CI)
p-value
Mortality
25%
14%
11.4% (0.85-21.63)
1.75 (0.99-3.09)
0.05
Reintubation
49%
49%
0%
0.99 (0.76-1.30)
ns

Did this RCT “killed” NIV ?

Mortality %
80
70
60
6/9
50
40
30
7/14
General
COPD
20
10
28/114
*
15/107
0
NIV
Standard therapy
Esteban, A. et al. N Engl J Med 2004;350:2452-2460

TIME to REINTUBATION
%
80
70
60
50
40
30
20
10
0
patients
deaths
0-12 hr
13-24 hr
25-48 hr
49-72 hr
Epstein and Ciubotaru AJRCCM 1998;158:489-93

Another way to see the problem:
If timing is a key factor, why should
we wait until post-extubation
respiratory failure is overt ?

NIV to prevent extubation failure
in patients with successful SBT
Αναπνεσζηική
ανεπάρκεια
33%
16%
Ferrer et al. Am J Respir Crit Care Med 2006;173:164-70

Survival of patients receiving NIV to prevent
extubation failure in patients with successful SBT
subgroup
analysis
Ferrer et al. Am J Respir Crit Care Med 2006;173:164-70

Ferrer et al, Lancet 2009;374:1082-88

NIV after extubation in patients who develop
hypercapnia during a spontaneous breathing trial
Ferrer et al, Lancet 2009;374:1082-88

Time elapsed from extubation to development of
respiratory failure
NIV immediately after extubation
in patients who develop hypercapnia during a spontaneous breathing trial
Ferrer et al, Lancet 2009;374:1082-88

► NIV is beneficial
Summary
• To avoid intubation
• When spontaneous breathing trial fails in COPD
• To prevent extubation failure in COPD patients
► During CMV check mechanics and PEEPi
• To avoid hemodynamic compromise
• To avoid overdistention
► Triggering: not really clinically important
► Wasted efforts
• Decrease support
• Apply external PEEP
► Weaning: No difference between different techniques
• PS vs T-piece
• The best technique is the one you know well