Comparison 5. Procedure time for overall cannulation.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
5.1 Difficulty levels defined by original studies	10	803	Mean Difference (IV, Random, 95% CI)	‐61.14 [‐161.33, 39.06]
5.1.1 Difficult	8	413	Mean Difference (IV, Random, 95% CI)	‐24.92 [‐323.09, 273.25]
5.1.2 No restriction by intravenous access difficulty level	2	390	Mean Difference (IV, Random, 95% CI)	‐77.42 [‐185.70, 30.86]
5.2 Difficulty levels defined by the success rate with the landmark method	10	803	Mean Difference (IV, Random, 95% CI)	‐61.14 [‐161.33, 39.06]
5.2.1 Difficult	5	322	Mean Difference (IV, Random, 95% CI)	‐116.99 [‐662.82, 428.83]
5.2.2 Moderate	3	428	Mean Difference (IV, Random, 95% CI)	‐69.79 [‐176.18, 36.61]
5.2.3 Easy	1	35	Mean Difference (IV, Random, 95% CI)	131.60 [‐39.84, 303.04]
5.2.4 No data of the success rate	1	18	Mean Difference (IV, Random, 95% CI)	156.00 [‐450.08, 762.08]