Meta-analysis and trial sequential analysis of randomized evidence comparing general anesthesia vs regional anesthesia for laparoscopic cholecystectomy

Figure 4 Results of trial sequential analysis. A: Visual analogue scale (VAS) at 4 h; B: VAS at 8 h; C: VAS at 12 h; D: VAS at 24 h; E: Nausea and vomiting; F: Headache; G: Urinary retention; H: Operative time; I: Total operative and anesthetic time. The red inward-sloping dashed lines make up the trial sequential monitoring boundaries. To the right, the outward sloping red dashed lines make up the futility region. The solid blue line is the cumulative Z curve. The solid green line presents penalised Z value.