colonoscopy was not different in the Prepsystem (19 3 min) and the PEG (22 1 min) groups. Blood electrolytes were not significantly modified after bowel cleansing in both groups. Patient satisfaction was good to excellent in all cases in the Prepsystem group. Conclusion: The Prepsystem water infusion protocol appeared as effective as the splitted PEG protocol for bowel cleansing before colonoscopy. Patient tolerance of the Prepsystem was good. Further studies should evaluate the benefit of this protocole in patients with contraindications or poor tolerance to PEG cleansing or in ambulatory patients. Su1550 Establishing the Learning Curve for Achieving Competency in Performing Colonoscopy: a Systematic Review Neal Shahidi*, George Ou, Jennifer J. Telford, Robert a. Enns Department of Medicine, Division of Gastroenterology, University of British Columbia, Vancouver, BC, Canada Background: Training in colonoscopy (CSPY) is a difficult but an integral part of gastroenterology and surgical training programs. However, the number of procedures required to achieve competence is not well established, leading to significant heterogeneity among current guidelines. Aims: To assess the learning curve for achieving competency in performing CSPYs during gastroenterology and surgical training. Methods: Two investigators (NS and GO) independently searched MEDLINE (1946 June 2013) and the grey literature (bibliographies of included studies, pertinent review articles and guidelines) to identify relevant citations. Subsequently, after full-text review, studies meeting inclusion underwent data extraction with discrepancy among investigators resolved by consensus. A threshold of 90% independent cecal intubation rate (ICIR) was used as a minimum reference for competence. Results: 18 unique study populations, encompassing 38,000 CSPYs were included in our analysis. When stratifying by markers of competence: 10 studies used ICIR; 6 studies used ICIR with a cecal intubation time (CIT) limit; 1 study used ICIR with a procedural time limit; and 2 studies provided more comprehensive definitions of competence. Among the 10 studies that solely quantified ICIR, 4 studies were able to reach the reference competence estimate during analysis (90% ICIR), with trainees reaching competence between 140 to 305 CSPYs. In studies additionally setting a CIT (15 minutes 30 minutes) limit, competence was reached in 5 studies between 100 to 300 CSPYs. Of the 2 studies who provided more comprehensive estimates of competence, their reference competence thresholds were reached between 275 to 467 CSPYs. Conclusions: Our results suggest that as the definition of competence becomes more robust (i.e. acceptable for clinical practice) and incorporates more than just ICIR and CIT that the threshold to achieve competency continues to rise well above current recommendations. With newer levels of competence being promoted, present guidelines need to reassess the level of training required to adequately train endoscopists. Su1551 Split-Dose Sodium Picosulfate and Magnesium Citrate Preparation for Colonoscopy: Cleansing Effectiveness and Residual Gastric Volume and pH CeSar Prieto*, RAMoN AngoS, Maria Teresa BeteS, Susana De La Riva, Iago RodriGuez Lago, Cristina Carretero, Maite Herraiz, Alejandra Alzina Perez, Miguel a. MUnOz-Navas Gastroenterology, Clinica Universidad de Navarra, Pamplona, Spain Background: Split dose bowel preparations result in superior bowel cleanness. Although there is evidence that smaller residual gastric volumes (RGV) are obtained with fasting times of 2-4 hours when compared with more than 4 hours, and the relationship between fasting times for clear liquids and risk of pulmonary aspiration has not been demonstrated, there is still concern about the increased risk of aspiration when using a split-dosing regimen. Low-volume bowel preparation containing sodium picosulfate and magnesium citrate (PMC) has shown to be better tolerated, and at least as effective, as other cleansing agents. Aim: To compare the cleansing efficacy, RGV, gastric pH and tolerabilty between a PMC split-dose regimen and a traditional evening-before-procedurecomplete PMC regimen. Methods: Patients aged 18 to 80 ys. requiring elective gastroscopy (EGD) and colonoscopy in the same day were invited to participate. Exclusion criteria were: known gastroparesis, gastric outlet obstruction, hiatal herniaO4 cm, previous gastrointestinal resections excluding appendicectomy, renal insufficiency, active inflammatory bowel disease, and elevated anesthesic risk (ASA III-IV). Patients were distributed to split-dose group (1) or traditional regimen group (2) exclusively depending on the hour and date of medical visit. Group 1 patients were instructed to take a PMC sachet at 19:00 the evening before the procedure, and a second sachet 4 hours before the procedure. Group 2 patients were instructed to take 1 sachet at 15:00 and second sachet at 20:00 both the evening before the procedure. Tolerability was assesed by completing a questionnaire just before the procedure. Colonoscopy was performed immediately after EGD. Total gastric volume was suctioned off and collected in a graded AB318 GASTROINTESTINAL ENDOSCOPY Volume 79, No. 5S : 2014 specimen trap. Colon cleansing efficacy was assesed by Ottawa Bowel Preparation Scale (OBPS). Results: 206 patients were included (group 1: 116; group 2: 90). There were no significant differences in patient characteristics between the two groups. Mean time interval ( SD) between last reported ingestion was 3.63 hours ( 1.02) (range 2-6 hours) in the split-dosing group, and 11.59 ( 1.64) in the traditional regimen group. Mean RGV was significantly lower in group 1 than in group 2 (11.65 vs.17.50 ml; p!0.005). pH of RGV in group 1 was slightly higher than group 2 (2.06 vs.1.45; ns). Total, mid-colon and right-colon OBPS scores were significantly bettter in group 1 than in group 2 (3.47 vs 4.38, p!0.01; 1.18 vs 0.91, p!0.05; 1.16 vs 1.67 p!0.001, respectively). No significant differences in tolerabilty were found. No patient had evidence of aspiration. Conclusions: Patients receiving split-dose regimen of PMC have lower residual gastric volumes and superior cleansing levels, specially in right colon, than those receiving traditional regimen, suggesting an efficacy and safety adventage. SPLITDOSING (n[116) Mean (± SD) TRADITIONAL REGIMEN (n [ 90) Mean (± SD)