. 2017 Jun 1;21:127. doi: 10.1186/s13054-017-1698-x

Table 2.

Summary of findings: PS vs T-piece SBTs on SBT and extubation success

Outcome	Illustrative comparative risks^a (95% CI)		Risk ratio (95% CI)	Number of participants (trials)	Quality of evidence (GRADE)
Outcome	Assumed risk, T-piece	Corresponding risk, pressure support	Risk ratio (95% CI)	Number of participants (trials)	Quality of evidence (GRADE)
PS vs T-piece SBTs on SBT success	Study population		1.00 (0.89–1.11)	1901 (9 trials)	⊕ ⊕ ⊕⊝ moderate^b
PS vs T-piece SBTs on SBT success	766 per 1000	766 per 1000 (681–850)	1.00 (0.89–1.11)	1901 (9 trials)	⊕ ⊕ ⊕⊝ moderate^b
PS vs T-piece SBTs on extubation success	Study population		1.06 (1.02–1.1)	1904 (11 trials)	⊕ ⊕ ⊕⊝ moderate^c
PS vs T-piece SBTs on extubation success	749 per 1000	794^d per 1000 (764–824)	1.06 (1.02–1.1)	1904 (11 trials)	⊕ ⊕ ⊕⊝ moderate^c

PS pressure support, CI confidence interval, SBT spontaneous breathing trial, GRADE Grading of Recommendations Assessment, Development and Evaluation, NNT number needed to treat

^aThe assumed risk is based on the median control group risk across studies. The corresponding risk (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). NNT is 1000/(794–749) = 22 (95% CI 13–67)

^bThe Chittawatanarat [47] trial skews data, increases heterogeneity, and changes summary estimate of effect. It also changes our interpretation of the findings

^cMethodologic concerns with the Colombo trial (quasi-randomized) [34]; this trial carries 10% weight in the pooled extubation outcome meta-analysis

^dCorresponds to NNT of 794–749 = 45 or 1000/45 = 22 (95% CI 13–67)