Effect of Pressure Support vs Unassisted Breathing Through a Tracheostomy Collar on Weaning Duration in Patients Requiring Prolonged Mechanical Ventilation JAMA 2013;309(7): R3 이태인

2 Background Prolonged mechanical ventilation –More than 21days –13% of ventilated patients & 37% of ICU costs LTACH (Long-Term Acute Care Hospitals) Ventilator duration was influenced by weaning method –Pressure support vs SBT

3 Randomized study in patients transferred to an LTACH for weaning from prolonged ventilation to compare… –The length of time required for weaning method –The 6- and 12- month survival of patients

4 Method RML Specialty Hospital in Hinsdale, Illinois, US Eligible if they received mechanical ventilation for at least 21 days Excluded for the following reasons –Cardiopulmonary instability, profound neurological deficits, bilateral phrenic nerver injury, life expectancy of less than 3 months…

5 Measurements at study enrollment –Physiologic variables RR and tidal volume for 1 min, spontaneous breathing Maximal inspiratory pressure –Screening procedure Unassisted breathing for 5 days (120 hours) –Patients who developed respiratory distress were eligible for randomization –Randomization 2 groups : early-failure group & late-failure group

6 Weaning protocol –Tracheostomy Collar Group Day 1 : 12hrs(max) SBT vs 12hrs ventilator Day 2 : 12hrs(max) SBT vs 12hrs ventilator From Day 3 : 24hrs(max) SBT –Pressure-Support Group Assessed 3 times/day : 8 AM, 2 PM and 8 PM Day 1 : initial PS level 14cm H2O, -2cm H2O When PS 6cm H2O for at least 12hrs –24hrs(max) SBT

7 The primary outcome was weaning duration –Weaning was considered successful when patients breathed without ventilator assistance for at least 5 days The secondary outcome was mortality at 6 and 12 months for the overall group

8 Results

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13 Long-term mortality : equivalent P < 0.001Pressure-support groupTracheostomy collar group 6 months mortality55.92%51.25% 12 months mortality66.45%60.00%

14 Discussion Tracheostomy collar use resulted in earlier weaning than did pressure support in patients who required prolonged ventilation The influence of weaning method on rate of successful weaning was related to time taken to fail the screening procedure –Early-failure group vs Late failure group Mortality was equivalent between both groups

15 How best to define weaning : 5 days → 7 days The faster pace of weaning with tracheostomy collar use may be related to its effects on clinical decision making Severity of illness in the early-failure group may have had a greater influence on weaning outcome than did weaning method

16 Study limitations –The nature of weaning techniques made it impossible to mask treatment aggignment from clinical staff and research personnel after randomization –The time covariate was not significant in any of the models –The findings of patients in a LTACH do not permit simple extrapolation to patients in an ICU

17 Conclusion shorter median weaning timeno effect on survivalUnassisted breathing through a tracheostomy, compared with pressure support, resulted in shorter median weaning time, although weaning mode had no effect on survival at 6 and 12 months