ABSTRACT
BACKGROUND: Previous studies have confirmed the safety of polyethylene glycol plus ascorbic acid for healthy middle-aged adults but not for the elderly. The osmotic pressure of polyethylene glycol plus ascorbic acid is approximately twice that of plasma osmolality and may cause dehydration. OBJECTIVE: In this study, we determined whether dehydration was induced in elderly patients by polyethylene glycol plus ascorbic acid, and we analysed the data obtained in order to identify predictors of dehydration. METHODS: This was a prospective, uncontrolled, before-and-after intervention study. All patients older than 65 years who underwent colonoscopies at the Moji Medical Center were administered polyethylene glycol plus ascorbic acid prior to colonoscopy. Clinical variables before and after bowel preparation were measured and analysed statistically. A multiple linear regression analysis was performed to identify predictors of dehydration due to this procedure. RESULTS: Eighty-three patients were assessed for eligibility, and 74 clinical variables were ultimately analysed. A significant increase in the red blood cell count (4.10 versus 4.25 × 10(6)/mm(3)), haemoglobin level (12.4 versus 13.0 g/dL) and haematocrit (38.1% versus 39.4%) suggested the presence of hypovolaemia after the procedure (P < 0.001). The serum concentration of albumin before bowel preparation was identified as the only significant predictor of hypovolaemia (ß = 0.47, P = 0.0001, adjusted R (2) = 0.22). CONCLUSION: The serum concentration of albumin before bowel preparation predicted hypovolaemia caused by polyethylene glycol plus ascorbic acid in elderly patients. Therefore, care is needed in order to prevent hypovolaemia, especially in elderly patients with hypoalbuminaemia. TRIAL REGISTRATION: No. 000015724 (University Hospital Medical Information Network Center).
