Vitacca 2001.

Methods	Multicentre RCT Setting: The long‐term weaning units (LWUs) of the three hospitals: Gussago, Padova, and Casatenovo, Italy
Participants	52 tracheostomized patients with COPD mechanically ventilated for at least 15 days that T‐piece trial failure (difficult‐to‐wean) ‐ Mean age: 72.5 years ‐ Gender of participants: did not report ‐ Mechanical ventilation time: > 15 days (range 15‐ 39) ‐ Mean APACHE II: 17
Interventions	1‐ T‐tube with supplemental oxygen for 8 h (n=26) 2‐ PSV of 8 cmH2O for 8 h (n=26)
Outcomes	1‐ Weaning success rate 2‐ Time of weaning 3‐ LWU and hospital length of stay 4‐ Total MV duration 5‐ Failure of weaning 6‐ Mortality 7‐ Complications: pneumonia, arrhythmias and agitation
Notes	PSV group: the pressure support was decreased by 2 cmH2O twice a day until 8 cmH2O for 8 hours T‐tube: patients were disconnected from the ventilator and tried to breathe spontaneously twice a day, with duration from 30 min to 8h (30, 60 min, 2, 4, 8 h) Weaning success rate was considered when the patients able to tolerate at least a further 48 consecutive hours of spontaneous breathing through T‐tube Weaning failure (5) was considered when the patient died or who still needed MV after at least 30 consecutive days of weaning protocol
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	The patients were randomly assigned to either the PSV or T‐Tube using a random list generated by a computer with a central allocation with 3 different blocks of 20 subjects (data reported by first author)
Allocation concealment (selection bias)	Low risk	The final random list was sealed envelopes (data reported by first author)
Selective reporting (reporting bias)	Low risk	Clinically relevant outcomes
Other bias	Low risk	None suspected
Free of detection bias ?	High risk	The outcome assessors were not blinded
Free of attrition bias?	Low risk	The patient flow was clear and failure was considered when the patient died or MV for more 30 days