 One of the main limitations of these trials are the relatively small numbers, with just 20 per group in the Sinclair trial and 30 per groups in the Venn trials, yet even with small numbers an improvement in outcome was seen. A larger trial has recently been completed using a more invasive calibrated measure of cardiac output, targeting a somewhat aggressive oxygen delivery of 600mlminm2 using inotropic support in elderly fractured neck of femur patients. Few patients actually achieved this goal, however there was again a non-significant reduction in complications RR 0.79, 95 CI 0.54-1.16 however the trial was underpowered due to issues with recruitment. The trial recruited 149 patients in total and to date is the largest study to examine this population despite the impact that this population has on the health services both within the NHS and worldwide. In addition all of the trials described included in their recruitment a broad group of patients some of whom could be considered to be at low risk of post operative complications. 