Challand C, Struthers R, Sneyd JR, Erasmus PD, Mellor N, Hosie KB, Minto G Randomized controlled trial of intraoperative goal-directed fluid therapy in aerobically fit and unfit patients having major colorectal surgery. Br J Anaesth. 2012 Jan;108(1):53-62. doi: 10.1093/bja/aer273. Epub 2011 Aug 26.
Gómez-Izquierdo JC, Feldman LS, Carli F, Baldini G Meta-analysis of the effect of goal-directed therapy on bowel function after abdominal surgery. Br J Surg. 2015 May;102(6):577-89. doi: 10.1002/bjs.9747. Epub 2015 Mar 11. Review.
Gottlieb M, Bailitz J Comparison of Early Goal-Directed Therapy With Usual Care for Severe Sepsis and Septic Shock. Ann Emerg Med. 2015 Dec;66(6):632-4. doi: 10.1016/j.annemergmed.2015.05.025. Epub 2015 Jun 24.
Hunsicker O, Scott MJ, Miller TE, Baldini G, Feldheiser A Gastrointestinal morbidity as primary outcome measure in studies comparing crystalloid and colloid within a goal-directed therapy. Br J Anaesth. 2015 Jul;115(1):128-9. doi: 10.1093/bja/aev181.
Yates DR, Davies SJ, Milner HE, Wilson RJ Crystalloid or colloid for goal-directed fluid therapy in colorectal surgery. Br J Anaesth. 2014 Feb;112(2):281-9. doi: 10.1093/bja/aet307. Epub 2013 Sep 20.
Zheng H, Guo H, Ye JR, Chen L, Ma HP Goal-directed fluid therapy in gastrointestinal surgery in older coronary heart disease patients: randomized trial. World J Surg. 2013 Dec;37(12):2820-9. doi: 10.1007/s00268-013-2203-6.
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
