Table 2.

Summary of significance of outcome measures for two dimensional (2-D) ultrasound guidance compared with landmark method for catheterisation

	Internal jugular vein				Subclavian vein				Femoral vein
	No of placements				No of placements				No of placements
Variable	2-D ultrasound guidance	Landmark method	Effect size (95% CI)	P value	2-D ultrasound guidance	Landmark method	Effect size (95% CI)	P value	Doppler ultrasound guidance	Landmark method	Effect size (95% CI)	P value
Adults
Relative risk:
Failed catheter placement	296	312	0.14 (0.06 to 0.33)	<0.0001	25	27	0.14 (0.04 to 0.57)	0.006	20	20	0.29 (0.07 to 1.21)	0.09
Complication with placement	284	295	0.43 (0.22 to 0.87)	0.02	25	27	0.10 (0.01 to 0.71)	0.02	—	—	NA	NA
Failure on first attempt	162	179	0.59 (0.39 to 0.88)	0.009	—	—	NA	NA	—	—	NA	NA
Mean No:
Attempts to successful catheterisation	131	136	−1.50 (−2.53 to −0.47)	0.004	—	—	NA	NA	20	20	−2.70 (−5.26 to −0.14)	0.04
Seconds to successful catheterisation	180	192	−69.33 (−92.36 to −46.31)	<0.0001	—	—	NA	NA	20	20	−3.20 (−43.27 to 36.87)	0.9
Infants
Relative risk:
Failed placement	79	88	0.15 (0.03 to 0.64)	0.01	—	—	NA	NA	—	—	NA	NA
Complication with placement	79	88	0.27 (0.08 to 0.91)	0.03	—	—	NA	NA	—	—	NA	NA
Failure on first attempt	—	—	NA	NA	—	—	NA	NA	—	—	NA	NA
Mean No:
Attempts to successful catheterisation	43	52	−2.00 (−2.78 to −1.22)	<0.0001	—	—	NA	NA	—	—	NA	NA
Seconds to successful catheterisation	59	68	−349.38 (−801.89 to 103.13)	0.13	—	—	NA	NA	—	—	NA	NA

NA=not available. All outcomes favoured ultrasound guidance (relative risk <1).