Effects of oral sodium phosphate solution, as a colon preparation agent, on the serum potassium level in patients undergoing colonoscopy at a Secondary Care Community Hospital

Abstract

Background : Colonoscopy is the gold standard investigation for assessing of the intra-luminal colorectal pathology. Effective bowel preparation contributed efficient visualizing of the colon. Osmotic laxatives such as sodium phosphate (NaP) are commonly used for colonic preparation for colonoscopy. A meta-analysis suggested that NaP offered a more effective and more readily completed preparation than PEG-based regimes. However, the use of sodium phosphate solution has been shown to significantly reduce the serum potassium level which is likely to affect cardiac rhythm in particular by prolonging the QT interval. But this affect was not clinically meaningful in most of patients. Sodium phosphate (NaP) are commonly used for colonic preparation for colonoscopy in Phukieo Rural Hospital a secondary care community hospital, the effect of oral sodium phosphate solution, as a colon preparation agent, on the serum potassium level in patients undergoing colonoscopy was evaluated.

Objective : To determine the effect of oral sodium phosphate solution, as a colon preparation agent, on the serum potassium level in patients undergoing colonoscopy.

Design : Retrospective cohort study.

Setting : Phukieo Rural Hospital, Chaiyaphum Province

Material and Methods : From January 2010 to December 2013, medical charts of 88 patients who were admitted to Phukieo Rural Hospital for colonoscopy were retrospectively reviewed. All patients were given sodium phosphate solutions as colon preparation agents. Basic tests included serum electrolytes (pre- and post-preparation serum potassium levels) and creatinine determination, electrocardiography (EKG) and chest radiographs. Changes in oxygen saturation, blood pressure, EKG, and any adverse events occurring during colonoscopy were monitored in all patients. The differences between the levels of serum potassium levels before and after colon preparation were tested for statistical significance.

Result : There was a 0.17 mmol/L average reduction in the serum potassium level after colon preparation in 88 patients. No significant adverse events occurred during colonoscopy. No potential risk factors associated with reduced post-sodium phosphate serum potassium levels were identified on analysis of covariance. No systematic association between post-sodium phosphate potassium levels and any potential risk factors was seen.

Conclusion : There was a mild reduction in the level of serum potassium after colon preparation with oral sodium phosphate solution in patients who underwent colonoscopy. The reduction was not clinically significant.