Beilin Y, Bernstein HH, Zucker-Pinchoff B The optimal distance that a multiorifice epidural catheter should be threaded into the epidural space. Anesth Analg. 1995 Aug;81(2):301-4.
Epidural and Position Trial Collaborative Group Upright versus lying down position in second stage of labour in nulliparous women with low dose epidural: BUMPES randomised controlled trial. BMJ. 2017 Oct 18;359:j4471. doi: 10.1136/bmj.j4471.
Grundy EM, Rao LN, Winnie AP Epidural anesthesia and the lateral position. Anesth Analg. 1978 Jan-Feb;57(1):95-7.
Halpern SH, Walsh V Epidural ropivacaine versus bupivacaine for labor: a meta-analysis. Anesth Analg. 2003 May;96(5):1473-1479. doi: 10.1213/01.ANE.0000052383.01056.8F.
Husemeyer RP, White DC Lumbar extradural injection pressures in pregnant women. An investigation of relationships between rate of infection, injection pressures and extent of analgesia. Br J Anaesth. 1980 Jan;52(1):55-60.
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.
