ABSTRACT
Colonoscopy and bowel preparation caused a number of serum electrolytes changes that may be dangerous in heart and kidney diseases and elderly patients. To determine the effect of serum electrolytes in patients who underwent colonoscopy and bowel preparation with PEG [Polyethylene Glycol] in Tehran Imam Khomeini hospital in 2008. Fifty nine patients who had been selected for elective colonoscopy after the detection of exclusion criteria were assessed prospectively. Serum level of sodium and potassium were analysed before bowel preparation with PEG [T[0], before colonoscopy T[1] and immediately after it T[2]. Serum calcium and phosphorus levels were measured just before and after PEG. Four patients [6.8%] did not follow the research protocol and were excluded. Four patients [6.8%] developed hyponatremia in T[1] that continued in T[2]. There were no significant differences in prevalence of Hyponatremia and means of sodium serum levels in T[0], T[1] and T[2]. Although there was a significant trend to decreased means of potassium levels of T[2] versus T[1] [P<0.01], but the maximum prevalence of Hypakalemia was in T[1] [10.9%] with only 3.8% new Hypokaliemia in T[2] and there was no significant difference. The prevalence of Hypocalcemia after PEG was 24% but there was no significant decrease. 36% of patients developed Hypophosphatemia after PEG preparation with a significant decrease in mean of serum Phosphorus level [P<0.05]. There was no significant relationship between electrolytes changes with age and sex. The serum electrolyte changes showed that preparation with PEG is a risk factor for development of Hypophosphatemia Colonoscopy and preparation with PEG may cause a significant decrease in potassium serum level