Turrentine FE, Wang H, Simpson VB. Surgical risk factors, morbidity, and mortality in elderly patients. J Am Coll Surg. 2006;203:865-77.

Story DA, Leslie K, Myles PS. Complications and mortality in older surgical patients in Australia and New Zealand (the REASON study): a multicentre, prospective, observational study. Anaesthesia. 2010;65:1022-30.

Mythen MG, Webb AR. Intra-operative gut mucosal hypoperfusion is associated with increased post-operative complications and cost. Intensive Care Med. 1994;20:99-104.

Bland RD, Shoemaker WC. Probability of survival as a prognostic and severity of illness score in critically ill surgical patients. Crit Care Med. 1985;13:91-5.

Pearse RM, Harrison DA, James P. Identification of the high risk surgical population in the United Kingdom. Crit Care. 2006;10:R81.

Older P, Hall A. Clinical review: how to identify high-risk surgical patients. Crit Care. 2004;8:369-72.

Lobo SM, Salgado PF, Castillo VG. Effects of maximizing oxygen delivery on morbidity and mortality in high-risk surgical patients. Crit Care Med. 2000;28:3396-404.

Moher D, Liberati A, Tetzlaff J. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ. 2009;339:b2535.

Sinclair S, James S, Singer M. Intraoperative intravascular volume optimization and length of hospital stay after repair of proximal femoral fracture: randomised controlled trial. BMJ. 1997;315:909-12.

Conway DH, Mayall R, Abdul-Latif MS. Randomised controlled trial investigating the influence of intravenous fluid titration using oesophageal Doppler monitoring during bowel surgery. Anaesthesia. 2002;57:845-9.

Gan TJ, Soppitt A, Maroof M. Goal-directed intraoperative fluid administration reduces length of hospital stay after major surgery. Anesthesiology. 2002;97:820-6.

Venn R, Steele A, Richardson P. Randomized controlled trial to investigate influence of the fluid challenge on duration of hospital stay and perioperative morbidity in patients with hip fractures. Br J Anaesth. 2002;88:65-71.

Wakeling HG, McFall MR, Jenkins CS. Intraoperative oesophageal Doppler guided fluid management shortens postoperative hospital stay after major bowel surgery. Br J Anaesth. 2005;95:634-42.

Noblett SE, Snowden CP, Shenton BK. Randomized clinical trial assessing the effect of Doppler-optimized fluid management on outcome after elective colorectal resection. Br J Surg. 2006;93:1069-76.

Donati A, Loggi S, Preiser JC. Goal-directed intraoperative therapy reduces morbidity and length of hospital stay in high-risk surgical patients. Chest. 2007;132:1817-24.

Lopes MR, Oliveira MA, Pereira VOS. Goal-directed fluid management based on pulse pressure variation monitoring during high-risk surgery: a pilot randomized controlled trial. Crit Care. 2007;11:R100.

Buettner M, Schummer W, Huettemann E. Influence of systolic-pressure-variation guided intraoperative fluid management on organ function and oxygen transport. Br J Anaesth. 2008;101:194-9.

Senagore A, Emery T, Luchtefeld M. Fluid management for laparoscopic colectomy: a prospective randomized assessment of goal directed administration of balanced salt solution or hetastarch coupled with an enhanced recovery program. Dis Colon Rectum. 2009;52:1935-40.

Jammer I, Ulvik A, Erichsen C. Does central venous oxygen saturation-directed fluid therapy affect postoperative morbidity after colorectal surgery? A randomized assessor-blinded controlled trial. Anesthesiology. 2011;113:1072-80.

Van Der Linden PJ, Dierick A, Wilmin S. A randomized controlled trial comparing an intraoperative goal-directed strategy with routine clinical practice in patients undergoing peripheral arterial surgery. Eur J Anaesthesiol. 2010;27:788-93.

Forget P, Lois F, De KM. Goal-directed fluid management based on the pulse oximeter-derived pleth variability index reduces lactate levels and improves fluid management. Anesth Analg. 2010;111:910-4.

Mayer J, Boldt J, Mengistu AM. Goal-directed intraoperative therapy based on autocalibrated arterial pressure waveform analysis reduces hospital stay in high-risk surgical patients: a randomized, controlled trial. Crit Care. 2010;14:R18.

Benes J, Chytra I, Altmann P. Intraoperative fluid optimization using stroke volume variation in high risk surgical patients: results of prospective randomized study. Crit Care. 2010;14:R118.

Cecconi M, Fasano N, Langiano N. Goal-directed haemodynamic therapy during elective total hip arthroplasty under regional anaesthesia. Crit Care. 2011;15:R132.

Challand C, Struthers R, Sneyd JR. Randomized controlled trial of intraoperative goal-directed fluid therapy in aerobically fit and unfit patients having major colorectal surgery. Br J Anaesth. 2012;108:53-62.

Brandstrup B, Svendsen PE, Rasmussen M. Which goal for fluid therapy during colorectal surgery is followed by the best outcome: near-maximal stroke volume or zero fluid balance?. Br J Anaesth. 2012;109:191-9.

Bartha E, Arfwedson C, Imnell A. Randomized controlled trial of goal-directed haemodynamic treatment in patients with proximal femoral fracture. Br J Anaesth. 2013;110:545-53.

Zhang J, Qiao H, He Z. Intraoperative fluid management in open gastrointestinal surgery: goal-directed versus restrictive. Clinics (Sao Paulo). 2012;67:1149-55.

Salzwedel C, Puig J, Carstens A. Perioperative goal-directed hemodynamic therapy based on radial arterial pulse pressure variation and continuous cardiac index trending reduces postoperative complications after major abdominal surgery: a multi-center, prospective, randomized study. Crit Care. 2013;17:R191.

Scheeren TWL, Wiesenack C, Gerlach H. Goal-directed intraoperative fluid therapy guided by stroke volume and its variation in high-risk surgical patients: a prospective randomized multicentre study. J Clin Monit Comput. 2013;27:249-57.

Zhang J, Chen CQ, Lei XZ. Goal-directed fluid optimization based on stroke volume variation and cardiac index during one-lung ventilation in patients undergoing thoracoscopy lobectomy operations: a pilot study. Clinics (Sao Paulo). 2013;68:1065-70.

Forget P, Lois F, Kartheuser A. The concept of titration can be transposed to fluid management, but does is change the volumes? Randomised trial on pleth variability index during fast-track colonic surgery. Curr Clin Pharmacol. 2013;8:110-4.

Zakhaleva J, Tam J, Denoya PI. The impact of intravenous fluid administration on complication rates in bowel surgery within an enhanced recovery protocol: a randomized controlled trial. Colorectal Dis. 2013;15:892-9.

Srinivasa S, Taylor MH, Singh PP. Randomized clinical trial of goal-directed fluid therapy within an enhanced recovery protocol for elective colectomy. Br J Surg. 2013;100:66-74.

McKenny M, Conroy P, Wong A. A randomised prospective trial of intra-operative oesophageal Doppler-guided fluid administration in major gynaecological surgery. Anaesthesia. 2013;68:1224-31.

Zheng H, Guo H, Ye JR. Goal-directed fluid therapy in gastrointestinal surgery in older coronary heart disease patients: randomized trial. World J Surg. 2013;37:2820-9.

Peng K, Li J, Cheng H. Goal-directed fluid therapy based on stroke volume variations improves fluid management and gastrointestinal perfusion in patients undergoing major orthopedic surgery. Med Princ Pract. 2014.

Meng L, Tran NP, Alexander BS. The impact of phenylephrine, ephedrine, and increased preload on third-generation Vigileo-FloTrac and esophageal Doppler cardiac output measurements. Anesth Analg. 2011;113:751-7.

Feldheiser A, Hunsicker O, Krebbel H. Oesophageal Doppler and calibrated pulse contour analysis are not interchangeable within a goal-directed haemodynamic algorithm in major gynaecological surgery. Br J Anaesth. 2014.

Chikhani M, Moppett IK. Minimally invasive cardiac output monitoring: what evidence do we need. Br J Anaesth. 2011;106:451-3.

Critchley LA, Lee A, Ho AM. A critical review of the ability of continuous cardiac output monitors to measure trends in cardiac output. Anesth Analg. 2010;111:1180-92.

Srinivasa S, Lemanu DP, Singh PP. Systematic review and meta-analysis of oesophageal Doppler-guided fluid management in colorectal surgery. Br J Surg. 2013;100:1701-8.

Jhanji S, Vivian-Smith A, Lucena-Amaro S. Haemodynamic optimization improves tissue microvascular flow and oxygenation after major surgery: a randomised controlled trial. Crit Care. 2010;14:R151.

Della Rocca G, Ventrugno L, Tripi G. Liberal or restricted fluid administration: are we ready for a proposal of a restricted intraoperative approach?. BMC Anesthesiol. 2014;14:62.

Kristensen SD, Knuuti J, Saraste A. 2014 ESC/ESA Guidelines on non-cardiac surgery: cardiovascular assessment and management: The Joint Task Force on non-cardiac surgery: cardiovascular assessment and management of the European Society of Cardiology (ESC) and the European Society of Anaesthesiology (ESA). Eur Heart J. 2014;35:2383-431.

Multicentre study on peri- and postoperative central venous oxygen saturation in high-risk surgical patients. Crit Care. 2006;10:R158.

Arulkumaran N, Corredor C, Hamilton MA. Cardiac complications associated with goal-directed therapy in high-risk surgical patients: a meta-analysis. Br J Anaesth. 2014;112:648-59.

Hamilton MA, Cecconi M, Rhodes A. A systematic review and meta-analysis on the use of preemptive hemodynamic intervention to improve postoperative outcomes in moderate and high-risk surgical patients. Anesth Analg. 2011;112:1392-402.

Cecconi M, Corredor C, Arulkumaran N. Clinical review: goal-directed therapy - what is the evidence in surgical patients? The effect on different risk groups. Crit Care. 2013;17:209-23.

Rhodes A, Cecconi M, Hamilton M. Grounds goal-directed therapy in high-risk surgical patients: a 15-year follow-up study. Intensive Care Med. 2010;36:1327-32.

Grocott MPW, Dushianthan A, Hamilton MA. Perioperative increase in global blood flow to explicit defined goals and outcomes after surgery: a Cochrane systematic review. Br J Anaesth. 2013;111:535-48.

Sandham JD, Hull RD, Brant RF. A randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients. N Engl J Med. 2003;348:5-14.

Manecke G, Asemota A, Michard F. Tackling the economic burden of postsurgical complications: would perioperative goal-directed fluid therapy help?. Crit Care. 2014;18:566.

Bartha E, Davidson T, Hommel A. Cost-effectiveness analysis of goal-directed hemodynamic treatment of elderly hip fracture patients: before clinical research starts. Anesthesiology. 2012;117.

Mowatt G, Houston G, Hernandez R. Systematic review of the clinical effectiveness and cost-effectiveness of oesophageal Doppler monitoring in critically ill and high-risk surgical patients. Health Technol Assess. 2009;13.

Technology Assessment Program: esophageal Doppler ultrasound-based cardiac output monitoring for real-time therapeutic management of hospitalized patients. 2007.

Jammer I, Wickboldt N, Sander M. Standards for definitions and use of outcome measures for clinical effectiveness research in perioperative medicine: European Perioperative Clinical Outcome (EPCO) definitions: a statement from the ESA-ESICM joint taskforce on perioperative outcome measures. Eur J Anaesthesiol. 2014.

Corcoran T, Rhodes JE, Clarke S. Perioperative fluid management strategies in major surgery: a stratified meta-analysis. Anesth Analg. 2012;114:640-51.