A meta-analysis of randomized controlled trials evaluated the clinical effectiveness of ultrasound-guided central venous cannulation compared with the landmark method. The study included 18 trials involving 1646 participants. Real-time two-dimensional ultrasound guidance for internal jugular vein cannulation in adults was associated with significantly lower failure rates (relative risk 0.14, 95% CI 0.06 to 0.33) and on the first attempt (0.59, 0.39 to 0.88) compared with the landmark method. Limited evidence suggested two-dimensional ultrasound guidance was more effective for subclavian and femoral vein procedures in adults. In infants, two-dimensional ultrasound guidance showed higher success rates for internal jugular vein cannulation. Doppler guidance was more successful than the landmark method for internal jugular vein cannulation in adults, but less successful than the landmark method for subclavian vein procedures. No significant difference was found between techniques for internal jugular vein cannulation in infants. Indirect comparison suggested two-dimensional ultrasound guidance was more successful than Doppler guidance for subclavian vein procedures in adults. The study concluded that evidence supports the use of two-dimensional ultrasound guidance for central venous cannulation. The landmark method remains important for subclavian vein procedures. Ultrasound guidance reduces technical failure rates, complications, and time to successful cannulation. It is likely to reduce risks for patients and improve efficiency for NHS trusts. However, there is a potential for deskilling in the landmark method. The National Institute for Clinical Excellence recommends maintaining the landmark method alongside ultrasound guidance. Economic modeling suggested that ultrasound guidance could save NHS resources. The study adds that ultrasound guidance is quicker and safer than the landmark method in both adults and children, and more effective than Doppler guidance for difficult procedures.A meta-analysis of randomized controlled trials evaluated the clinical effectiveness of ultrasound-guided central venous cannulation compared with the landmark method. The study included 18 trials involving 1646 participants. Real-time two-dimensional ultrasound guidance for internal jugular vein cannulation in adults was associated with significantly lower failure rates (relative risk 0.14, 95% CI 0.06 to 0.33) and on the first attempt (0.59, 0.39 to 0.88) compared with the landmark method. Limited evidence suggested two-dimensional ultrasound guidance was more effective for subclavian and femoral vein procedures in adults. In infants, two-dimensional ultrasound guidance showed higher success rates for internal jugular vein cannulation. Doppler guidance was more successful than the landmark method for internal jugular vein cannulation in adults, but less successful than the landmark method for subclavian vein procedures. No significant difference was found between techniques for internal jugular vein cannulation in infants. Indirect comparison suggested two-dimensional ultrasound guidance was more successful than Doppler guidance for subclavian vein procedures in adults. The study concluded that evidence supports the use of two-dimensional ultrasound guidance for central venous cannulation. The landmark method remains important for subclavian vein procedures. Ultrasound guidance reduces technical failure rates, complications, and time to successful cannulation. It is likely to reduce risks for patients and improve efficiency for NHS trusts. However, there is a potential for deskilling in the landmark method. The National Institute for Clinical Excellence recommends maintaining the landmark method alongside ultrasound guidance. Economic modeling suggested that ultrasound guidance could save NHS resources. The study adds that ultrasound guidance is quicker and safer than the landmark method in both adults and children, and more effective than Doppler guidance for difficult procedures.