Comparison of outcomes of goal-directed fluid optimisation guided by LiDCOrapid and conventional oesophageal Doppler

INTERVENTION: Anaesthetist randomised to use either: 1. LiDCOrapid in intervention group OR 2. Conventional oesophageal Doppler cardiac output monitoring in control arm to guide goal‐directed fluid therapy Both monitors will be attached intraoperatively to allow paired readings. The anaesthetist will be blinded to the measurements of other monitor not being used. CONDITION: Improving perioperative care for elective colorectal surgery ; Surgery PRIMARY OUTCOME: Post‐operative length of stay (in days) SECONDARY OUTCOME: 1. Intra‐operative oxygen delivery index values; 2. Intra‐operative intravenous fluid volumes; 3. Intra‐operative differences in % change stroke volume; 4. Morbidity ; 5. Functional recovery (mobility and return of gastrointestinal function) ; 6. In‐hospital and 30‐day mortality INCLUSION CRITERIA: 1. Elective or semi‐elective patients due to undergo colorectal surgery as part of Enhanced Recovery Protocol 2. Successful simultaneous LiDCOrapid and oesophageal Doppler monitoring throughout surgery