title: Efficacy and tolerability of low-volume (2 L) versus single- (4 L) versus split-dose (2 L + 2 L) polyethylene glycol bowel preparation for colonoscopy: randomized clinical trial.
abstract: OBJECTIVE
  To compare the efficacy and tolerability of a low-volume (2-L) polyethylene glycol (PEG) regimen for colonoscopy compared to single (4-L) or split-dose (2-L + 2-L) regimens.
  
  
  METHODS
  In-hospital patients who were candidates for colonoscopy were randomly assigned to: group 1 single-dose (PEG 4 L the day before the study, n = 60); group 2: split-dose (2 L the day before and 2 L on the day of the procedure, n = 61); and group 3: low-volume 2-L PEG solution (the day of the procedure, n = 59). A blinded evaluation of the quality of colonic preparation was assessed by the Boston bowel preparation scale.
  
  
  RESULTS
  Satisfactory bowel preparation of the right colon was more frequently reported for group 3 than for group 1 (70% vs 53%, P = 0.045), in the transverse colon it was 82% versus 69% (P = 0.032), and on the left side of the colon it was 80% versus 67.7% (P = 0.028). Compared to group 2, satisfactory bowel preparation in group 3 was similar in the transverse colon and left colon. Nausea, vomiting, and abdominal discomfort were less frequent in patients of group 3. Patients in group 3 had fewer sleep disorders and fewer hours of sleep loss compared to patients in the other groups.
  
  
  CONCLUSIONS
  Preparation with 2 L caused less abdominal discomfort and fewer sleep disorders. The split dose had a better quality of preparation in the right colon. Both preparations were clearly better than the 4-L preparation.
authors.affiliation: Department of Endoscopy, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Mexico City, Mexico.
authors.forename: Félix I
authors.initials: FI
authors.lastname: Téllez-Ávila
authors.forename: Enrique
authors.initials: E
authors.lastname: Murcio-Pérez
authors.forename: Angela
authors.initials: A
authors.lastname: Saúl
authors.forename: Salvador
authors.initials: S
authors.lastname: Herrera-Gómez
authors.forename: Francisco
authors.initials: F
authors.lastname: Valdovinos-Andraca
authors.forename: Victor
authors.initials: V
authors.lastname: Acosta-Nava
authors.forename: Rafael
authors.initials: R
authors.lastname: Barreto
authors.forename: Javier
authors.initials: J
authors.lastname: Elizondo-Rivera
mesh_terms: D002400:Cathartics / Q000008:administration & dosage*; D003113:Colonoscopy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011092:Polyethylene Glycols / Q000008:administration & dosage*; D011446:Prospective Studies; D007507:Therapeutic Irrigation / Q000379:methods*
chemical_list: D002400:Cathartics; D011092:Polyethylene Glycols
keywords: Boston bowel preparation scale; bowel preparation; colonoscopy; polyethylene glycol; polyp