Within the available ERAS studies subjective postoperative outcomes are employed and it is difficult to assess the true contribution of many of the individual protocol elements to postoperative recovery. The reduction in length of stay, in itself, may represent more efficient use of inpatient care rather than an improved rate of functional recovery. Further refinement and validation of the ERAS model will be achieved by establishing randomised controlled trials that test its feasibility and effectiveness within other surgical specialties, establish objective, reproducible outcome measures and examine the specific contribution of individual protocol elements within the ERAS protocol. It is expected that further improvement in postoperative recovery may specifically rely on reducing gut dysfunction in the early postoperative period. The establishment of randomised controlled trials and objective endpoints will facilitate testing individual element that target gastrointestinal recovery

This thesis demonstrates that the application of an ERAS model of care to hepatic surgery is feasible and results in a reduction in postoperative stay similar to that seen in colorectal surgery. This suggests that the ERAS programme of care may be extrapolated to other surgical specialties. The present thesis also demonstrates that activity meters and stable isotope gastric empting breath tests can be employed in the early postoperative period to provide objective measures of postoperative recovery. Most significantly this thesis demonstrates through a randomised controlled trial that within an ERAS protocol early routine administration of laxatives can improve postoperative rate of gastrointestinal recovery following hepatic resection.

The Enhanced Recovery After Surgery model of perioperative care targets the obstacles to recovery following major abdominal surgery: pain, gastrointestinal dysfunction and immobility. This model of care combines elements that have individually been shown to attenuate the surgical stress response, reduce postoperative analgesia requirement or maintain perioperative nutrition. Through combining these elements it has been possible to improve early postoperative function and reduce the requirement for hospital stay with an unaltered or even reduced complication rate.