Weaning from MVJ.G. van der Hoeven

Radboud University Nijmegen Medical Centre

Normal weaning

Clinical improvement, P/F ratio > 150 (FiO2 ≤ 0.5 en PEEP ≤ 8), stable hemodynamics

SBT (30 minutes - 2 hrs) T-piece/CPAP/PSV

Success Failure

Cough?Swallow?

Extubation

Once daily2 - 25%

+ analysis

Introduction and focusIn most patients, mechanical ventilation can be dis con-tinued as soon as the underlying reason for acute respiratory failure has been resolved. However, 20% to 30% of patients are considered di! cult to wean from mechanical ventilation. Weaning failure is defi ned as the failure to pass a spontaneous-breathing trial or the need for reintubation within 48 hours following extubation [1]. " e risks associated with post-extubation distress and reintubation are considerable. " erefore, clinicians often choose to use a two-step diagnostic approach before extu bation. First, weaning parameters are assessed (screening), and, second, a weaning trial is initiated. " e validity of the di# erent screening tools (for weaning), such as the rapid shallow breathing index and maximal inspiratory pressure, has been discussed in detail else-where [2]. Di# erent techniques have been used for wean-ing and these include gradual reduction in mandatory rate during intermittent mandatory ventilation, gradual reduction in pressure support, and spontaneous breath-ing through a T-piece. Esteban and colleagues [3] con-cluded that trials of spontaneous breathing resulted in

faster liberation from mechanical ventilation compared with weaning using pressure support or intermittent mandatory ventilation. However, other studies failed to prove the superiority of spontaneous-breathing trials over pressure support ventilation as a weaning technique [4,5]. " ese di# erences in outcome most likely are related to the di# erent designs of these studies, patient charac-teristics, and durations of mechanical ventilation before initiation of weaning. In-depth discussion of weaning techniques is beyond the scope of this paper and has been published earlier [2].

" e pathophysiology of weaning failure is complex and often multifactorial. Accordingly, determining the reason and subsequently developing a treatment strategy require a dedicated clinician with in-depth knowledge of the pathophysiology of weaning failure. Several reviews have been published on weaning failure, but most focus on only one aspect of weaning and therefore are of limited help to clinicians. Complex clinical problems probably benefi t from a structured approach. An ‘ABC approach’ is valuable in training juniors in trauma management [6]. In this paper, we present an opinion-based ‘ABC approach’ for di! cult weaning. Unlike the ABC in trauma medicine (‘treat fi rst that kills fi rst’), our ‘weaning ABC’ does not emphasize a specifi c order of assessment but is purely alphabetical and has the advantage of ‘forcing’ the clinician to systematically review the most likely causes for failed weaning. With the understanding of the barriers that impede successful weaning in a specifi c patient, a tailored treatment strategy that may reduce duration of mechanical ventilation can be designed. " e following topics should be evaluated in a di! cult-to-wean patient (Figure 1): airway and lung dysfunction, brain dysfunction, cardiac dysfunction, diaphragm dys-function, and endocrine dysfunction. " e algorithm presented in Figure 1 shows possible strategies to confi rm the role of any of these items and options to reduce the contribution to weaning failure.

Airway and lung dysfunctionElevated airway resistance, reduced respiratory system com pliance, and impaired gas exchange increase the work of breathing and as such contribute to weaning

AbstractAbout 20% to 30% of patients are di! cult to wean from invasive mechanical ventilation. The pathophysiology of di! cult weaning is complex. Accordingly, determining the reason for di! cult weaning and subsequently developing a treatment strategy require a dedicated clinician with in-depth knowledge of the pathophysiology of weaning failure. This review presents a structural framework (‘ABCDE’) for the assessment and treatment of di! cult-to-wean patients. Earlier recognition of the underlying causes may expedite weaning from mechanical ventilation.

© 2010 BioMed Central Ltd

Clinical review: The ABC of weaning failure - a structured approachLeo M Heunks* and Johannes G van der Hoeven

R E V I E W

*Correspondence: l.heunks@ic.umcn.nlDepartment of Intensive Care Medicine (632), Radboud University Nijmegen Medical Centre, Postbox 9101, 6500 HB Nijmegen, The Netherlands

Heunks and van der Hoeven Critical Care 2010, 14:245 http://ccforum.com/content/14/6/245

© 2010 BioMed Central Ltd

Recognise those at risk

0

15

30

45

60

Simple weaning Difficult weaning Prolonged weaning

6

39

55

%

N = 2714

Extubation > 7 daysfrom first attempt of withdrawal

Peñuelas O. Am J Respir Crit Care Med 2011;184:430-437

Disease severity at admissionDuration of MV before first attempt

Chronic pulmonary diseasePneumonia

PEEP before weaning

Extubation outcome after prolonged MV

CharacteristicsSuccessful extubation

(N = 92)Failed extubation

(N = 27)P-value

Respiratory rate > 30 46 (50%) 15 (56%) 0,612

Minute ventilation > 10 49 (53%) 14 (52%) 0,897

Tidal volume < 5 ml/kg 27 (29%) 10 (37%) 0,448

RSBI > 105 42 (46%) 14 (52%) 0,57

PI max < - 20 cm H2O 9 (10%) 2 (7%) 0,999

GCS > 10 65 (71%) 18 (67%) 0,692

Ineffective cough 27 (29%) 23 (85%) < 0.001

Abundant secretions 8 (9%) 2 (7%) 0,999

Purulent secretions 31 (34%) 9 (33%) 0,972

Positive fluid balance 22 (24%) 10 (37%) 0,176

MV for 25 ± 6 days

Chun-Ta Huang. Resp Care 2013

What can we do in the early phase?

Try to avoid controlled ventilationJaber S. Am J Respir Crit Care Med 2011;183:364-371

Prevent excessive support

Blackwood B. BMJ 2011;342:c7237

Sedation - SLEAP trial

• Does daily sedation interruption improve outcome when protocolised sedation is already implemented?

• Multicenter RCT: Protocolised sedation ± daily sedation interruption (N = 423)

• Primary outcome - time to successful extubation

Mehta S. JAMA 2012;308:1985-1992

Mehta S. JAMA 2012;308:1985-1992

Protocol Protocol + Daily interruption P-value

Successful extubation (D) 7 (3 - 12) 7 (4 - 13) 0.52

Days in ICU (D) 10 (6 - 20) 10 (5 - 17) 0.36

ICU mortality (%) 24.9 23.4 0.72

Hospital mortality (%) 30.1 29.6 0.89

Higher nursing workload with daily interruptionMore sedatives/opiates with daily interruption

Determine excessive load

TLC$

0$Ppl$/$Pes$ +$-$

FRC$

Lung$volume$

passive$infla9on$$(relaxed$chestwall)$

ac9ve$infla9on$(lung$elas9c$recoil)$

resis9ve$inspiratory$WOB$

elas9c$inspiratory$WOB$

PEEPi

PEEPi$inspiratory$WOB$

expiratory$WOB$FRC$

Vt$

Vt$

Load reduction

• Decrease airway resistance (major/minor airways)

• Treat pulmonary edema / atelectasis

• Remove pleural fluid

Remove pleural fluidN = 168

Retrospective study

0

2

4

6

8

PF drainage Control

Dura

tion

of M

V (D

ays)

P = 0.03

Kupfer Y. Chest 2011;139:519-523

Pleura effusion drainage in MV patients

PaO2/FiO2 ↑ 18% (95 CI 5 - 33%)

Pneumothorax 3.4% (95 CI 1.7 - 6.5%)

Hemothorax 1.6% (95 CI 0.8 - 3.3%)

Pneumothorax with ECHO

OR 0.32 (0.08 - 1.19)

19 observational studies (N = 1124)Goligher EC. Crit Care 2011;15:R46

Spontaneous Breathing Trial

Work of Breathing ↑ Adrenergic stress ↑ IT pressure ↓

RV dilatation and increased LV afterload

Increase in LV preload / decrease in LV compliance

Pulmonary edema

Diastolic heart failureA frequent cause of weaning failure

0

5

10

15

20

25

Baseline Spontaneous ventilation

E/Ea

Failure Success

Moschietto S. Crit Care 2012;16:R81

BNP guided weaningN = 304BNP ≥ 200 pg/ml

Dessap AM. Am J Respir Crit Care Med 2012;186:1256-1263

0"

50"

100"

150"

200"

250"

MV" Start"trial" Einde"trial"

Systolische+bloe

ddruk+(m

m+Hg)+

Controle"

Nitroglycerine"

0"

5"

10"

15"

20"

25"

30"

35"

MV" Start"trial" Einde"trial"

Wiggedruk

)(mm)Hg))

Controle"

Nitroglycerine"

COPD - N = 12

After failure SBT (control) 90% successful with NTG

Routsi C. Crit Care 2010;14:R204

Consider nitrates

Other inotropic agentsDobutamine/Levosimendan in 10 COPD patients withlarge increase in PAOP during spontaneous breathing

Ouanes-Besbes L. J Crit Care 2011;26:15-21

RPP = rate pressure product

If the diaphragm is weak

• Early mobilisation

• Electrical muscle stimulation

• Respiratory muscle training

• Medication

Early mobilisationN = 104

Control Protocol P-value

Independent at HD 59% 35% 0.02

ICU delirium (D) 4 (2-7 2 (0-6) 0.03

ICU paresis at HD 49% 31% 0.09

Ventilator-free days 21 23.5 0.05

LOS ICU 7.9 5.9 0.08

Schweickert WD. Lancet 2009;373:1874-1882

Electrical stimulationN = 140 - only 52 evaluated

0

15

30

45

60

CIPNP (%) MRC score

EMS Control

P = 0.04 P = 0.04

MV significantly shorter in EMS group (1 [0-10] vs 3 [0 - 44], p 0.003)

Routsi C. Crit Care 2010;14:R74

• Daily sessions of 55 minutes

• Bilateral vastus lateralis/medialis and peroneus longus

• Biphasic, 45 Hz, 0.4 ms pulse duration, 12 seconds on and 6 seconds off

Muscle training

Threshold® PEPRespironics

Threshold® IMTRespironics

Inspiring throughexhalation port

4 sets of 6 - 10 breaths per day (5 days/week)

PFlex® IMTRespironics

Efficacy trial

0

20

40

60

80

Weaned D 28

47

71

%

IMT Sham

-80

-60

-40

-20

Pre PostM

IP (c

mH

2O)

IMT Sham

P < 0.0001

P = 0.039 N = 69

Martin AD. Crit Care 2011;15:R84

Inspiratory muscle strength Weaning success

Weaning duration (hours) Survival

Moodie L. J Physiother 2011;57:213-221

Muscle damage in COPD patients? - Optimal program?

van Hees HWH. Am J Respir Crit Care Med 2009;179:41-47

Myosin heavy Chain Slow

Non-COPD COPD

Levosimendan improves neuromechanical efficiency

Doorduin J. Am J Respir Crit Care Med 2012;185:90-95

Conclusions

• Prevention extremely important

• Weaning protocol - diagnostic scheme

• Remove pleural fluid

• Remember and treat diastolic dysfunction

• Early mobilisation

• IMT