Physiologic effects of bowel preparation.
OBJECTIVE
Despite the universal use of bowel preparation before colonoscopy and colorectal surgery, the physiologic effects have not been described in a standardized setting. This study was designed to investigate the physiologic effects of bowel preparation.


METHODS
In a prospective study, 12 healthy volunteers (median age, 63 years) underwent bowel preparation with bisacodyl and sodium phosphate. Fluid and food intake were standardized according to weight, providing adequate calorie and oral fluid intake. Before and after bowel preparation, weight, exercise capacity, orthostatic tolerance, plasma and extracellular volume, balance function, and biochemical parameters were measured.


RESULTS
Bowel preparation led to a significant decrease in exercise capacity (median, 9 percent) and weight (median, 1.2 kg). Plasma osmolality was significantly increased from 287 to 290 mmol kg(-1), as well as increased phosphate and urea concentrations, whereas calcium and potassium concentrations decreased significantly after bowel preparation. No differences in plasma or extracellular volumes were seen. Orthostatic tolerance and balance function did not change after bowel preparation.


CONCLUSIONS
Bowel preparation has significant adverse physiologic effects, which may be attributed to dehydration. The majority of these findings is small and may not be of clinical relevance in otherwise healthy patients undergoing bowel preparation and following recommendations for oral fluid intake.
Holte
Kathrine
K
Department of Surgical Gastroenterology, Hvidovre University Hospital, Hvidovre, Denmark. kathrine.holte@dadlnet.dk
Nielsen
Kristine Grubbe
KG
Madsen
Jan Lysgård
JL
Kehlet
Henrik
H
D000368:Aged; D001726:Bisacodyl / Q000009:adverse effects* / Q000494:pharmacology*; D001835:Body Weight; D002400:Cathartics / Q000009:adverse effects* / Q000494:pharmacology*; D003113:Colonoscopy; D003107:Colorectal Surgery; D003681:Dehydration / Q000139:chemically induced*; D004733:Enema; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010710:Phosphates / Q000009:adverse effects* / Q000494:pharmacology*; D011300:Preoperative Care; D018667:Tilt-Table Test
D002400:Cathartics; D010710:Phosphates; D001726:Bisacodyl; C018279:sodium phosphate