This document discusses weaning and extubation in pediatrics. It defines weaning as transitioning from ventilatory support to spontaneous breathing, and extubation as separating a patient from their ventilator. Successful weaning and extubation means maintaining effective gas exchange without mechanical support. Factors that indicate readiness for weaning include improving underlying conditions, adequate gas exchange, no undue burden on respiratory muscles, and the ability to sustain spontaneous ventilation as support decreases. Spontaneous breathing trials can assess readiness for extubation. Protocols for weaning and criteria for extubation can help optimize outcomes in pediatrics.

1. Weaning and Extubation:
A Pediatric Perspective
Ira M. Cheifetz, MD, FCCM, FAARC
Professor of Pediatrics
Chief, Pediatric Critical Care
Medical Director, PICU & Peds Resp Care
Duke Children’s Hospital

2. Weaning and Extubation
‘The separation of a patient from his
ventilator is very nearly pure art.’
– Donald F. Egan, 1977
‘Fundamentals of Respiratory Therapy’

3. Definitions
 Weaning: transition from ventilatory support
to complete spont breathing
 Success: maintaining effective gas
exchange with complete spont breathing
 Failure: inability to sustain effective gas
exchange w/o mechanical support within
48 hours of extubation

4. Definitions
 Spontaneous breathing trial (SBT)
– test of the ability to maintain complete
spontaneous breathing (i.e., extubation
readiness)
– failure is the inability to maintain effective gas
exchange with a RR within acceptable limits

5. Indications for Weaning
 Improving underlying disease process
 ‘Adequate’ gas exchange
 No undue burden on respiratory muscles
– cardiac insufficiency
– significant hyperinflation
– severe malnutrition
– multiorgan system dysfunction / failure
 Patient is capable of sustaining spontaneous
ventilation as ventilator support is decreased.

6. Effort of Breathing
 Respiratory rate
 Spontaneous tidal volume
 WOB
– paradoxical breathing / retractions
– esophageal manometry
 Inspiratory pressure of a spont breath (Pi)
 Maximal negative insp pressure (NIF)
 O2 cost of breathing

7. Factors that Contribute to Insp WOB
 ETT size / ventilator circuit deadspace
 Demand valves in the circuit
 Patient - ventilator dys-synchrony
 Trigger: pressure vs. flow
 Distal vs. proximal sensing (??)
 Any additional load on resp muscles

8. Adequacy of Gas Exchange
 Oxygenation
– PaO2/FiO2
– Oxygenation index: (FiO2 x Paw) / PaO2
– alveolar-arterial O2 gradient
– venous admixture; intrapulm shunt fraction
 Ventilation
– PaCO2
– physiological dead space
– EtCO2 - PaCO2 difference
– Fraction of ventilation provided by the vent

9. Vent Mode and Weaning Outcome
 PSV decreased duration of weaning
– Brochard, Am J Resp Crit Care Med, 1994
 Multicenter center study in adults:
– Esteban, N Engl J Med, 1995
– daily SBT led to extubation 3x faster than
IMV and 2x faster than PSV
– multiple daily SBTs were as successful as
a daily trial

10. Prolonged Ventilation
– ↑ nosocomial pneumonia
– ↑ airway injury
– ↑ VILI
– ↑ LOV & LOS
– ↑ cost
– ↓ patient & family satisfaction

11. Failed Extubation
– ↑ nosocomial pneumonia
– ↑ airway injury
– ↑ VILI
– ↑ LOV & LOS
– ↑ cost
– ↓ patient & family satisfaction
– mortality
 Children requiring reintubation within 48 hrs
had significantly  mortality than patients
successfully extubated (20% vs. 2%, p < 0.001)
Esteban, AJRCCM, 2001.

12. % spont breathing
% spont breathing
100
0
Time of extubation
Optimal Balance
Weaning time
100
% ventilator support
0

13. Should all adult pts be gradually
withdrawn from mech ventilation?
 No!
 Majority of adult patients who pass a SBT
are extubated within 24 hours
– Esteban, NEJM, 1995
– Brochard, AJRCCM, 1994

14. Should all peds pts be gradually
withdrawn from mech ventilation?
 Answer remains: No!
 PALISI: 58% of pts initially tested with a
minimal PS trial passed and were extubated
– Randolph, JAMA 2002
 77% of pts who underwent a SBT passed &
were extubated without weaning
– Farias, Inten Care Med, 1998

15. Weaning Protocols
Study Date N ↓ LOV p
Kollef 1997 357 1.4 d 0.029
Ely 1996 300 1.5 d 0.001
Marelich 2000 253 2.3 d 0.0001
Kollef, CCM, 1997
Ely, AJRCCM, 1996
Marelich, Chest, 2000

16. On the other hand….
 No differences between protocol & non-protocol
weaning for children.
 Duration of weaning (n = 182; p=0.75)
– 2.9 days in the ‘protocol’ groups
(median 1.7 d)
– 3.2 days in the ‘no protocol’ group
(median 2.0 d)
 Weaning protocols for ventilated pediatric pts
with ALI do NOT shorten LOV.
Randolph, JAMA, 2002.

17. Weaning & Sedation
Randolph, JAMA, 2002.

18. Extubation Criteria in Adults
 Respiratory frequency to tidal volume ratio
– Yang, NEJM, 1991
– Tahvanainen, CCM, 1983
 T-piece trials
– Sahn, Chest, 1973
 Negative insp effort measurements
– Sahn, Chest, 1973
 CROP index
(compliance, rate, oxygenation, pressure)
– Yang, NEJM, 1991

19. Extubation Criteria in Peds
 No widely accepted criteria for predicting
successful extubation for pediatric pts.
 Successful extubation predictors:
 Low Risk Value High Risk Value
 Vtspont 6.5 ml/kg 3.5 ml/kg
 FiO2 0.30 > 0.40
 Paw < 5 cm H2O > 8.5 cm H2O
 OI 1.4 > 4.5
 FrVe 20% 30%
 PIP 25 cm H2O 30 cm H2O
 Cdyn 0.9 ml/kg/cm H2O < 0.4 ml/kg/cm H2O
Khan, CCM, 1996.

20. Vd/Vt and Successful Extubation
n=3 n=2 n=7
100%
n=13
90% Hubble, CCM, 2000
80%
70%
n=8
60% n=2
50%
40% n=3
30% n=4
20%
10%
n=2
0%
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Vd / Vt

21. Vd/Vt and Extubation
 Elevated physiologic dead space predicts
 Elevated physiologic dead space predicts
extubation failure
extubation failure
 Successful extubation in a heterogeneous
 Successful extubation in a heterogeneous
PICU population (p < 0.001)
PICU population (p < 0.001)
– Vd/Vt < 0.5: 24/25 (96%)
– Vd/Vt < 0.5: 24/25 (96%)
– Vd/Vt 0.5-0.65: 6/10 (60%)
– Vd/Vt 0.5-0.65: 6/10 (60%)
– Vd/Vt > 0.65: 2/10 (20%)
– Vd/Vt > 0.65: 2/10 (20%)
Hubble, CCM, 2000

22. General indications and
contraindications for extubation
 Indications  Contraindications
– alert or easily – obtunded
arousable – poor or absent cough
– good cough and gag or gag
– thin secretions easily – thick or copious
cleared from airway secretions requiring
– nl cardiac function frequent suctioning
– no MOSF – cardiac insufficiency
– MOSF

23. Causes for Extubation Failure
Excessive resp effort 42%
Poor resp effort 24%
Inadequate gas exchange 18%
Cardiovasc insufficiency 10%
Neurologic 6%

24. SBT Recommendations
 Perform a SBT when
– FiO2 ≤ 0.40 PEEP ≤ 6 PIP ≤ 25
– sedation has been decreased or stopped
– adequate insp drive
– improvement or resolution of underlying cause
– pharmacological control of bronchoconstriction
– absence of significant resp acidosis

25. Weaning and Extubation:
Conclusions
 Not all patients require weaning
 Extubation readiness testing decreases
LOV
 Ideal timing of extubation may still
remain more clinical art than science –
although this is changing with ERT