Mechanical bowel preparation for elective colorectal surgery. A prospective, randomized, surgeon-blinded trial comparing sodium phosphate and polyethylene glycol-based oral lavage solutions

Dis Colon Rectum. 1997 May;40(5):585-91. doi: 10.1007/BF02055384.


Aim: The aim of this study was to compare the cleansing ability, patient compliance, and safety of two oral solutions for elective colorectal surgery.

Methods: All eligible patients were prospectively randomized to receive either 4 l of standard polyethylene glycol (PEG) solution or 90 ml of sodium phosphate (NaP) as mechanical bowel preparation for colorectal surgery. A detailed questionnaire was used to assess patient compliance. In addition, the surgeons, blinded to the preparation, intraoperatively evaluated its quality. Postoperative septic complications were also assessed. The calcium serum level was monitored before and after bowel preparation. Statistical analysis was performed using the Wilcoxon's rank-sum test and Fisher's exact test.

Results: Two hundred patients, well matched for age, gender, and diagnosis, were prospectively randomized to receive either PEG or NaP solutions for elective colorectal surgery. All patients completed all phases of the trial. There was a significant decrease in serum calcium levels after administration of both NaP (mean, 9.3-8.8 mg/dl) and PEG (9.2-8.9 mg/dl), respectively (P < 0.0001), with no clinical sequelae. However, patient tolerance to NaP was superior to PEG: less trouble drinking the preparation (17 vs. 32 percent; P < 0.0002), less abdominal pain (12 vs. 22 percent; P = 0.004), less bloating (7 vs. 28 percent), and less fatigue (8 vs. 17 percent), respectively. Additionally, 65 percent of patients who received the NaP preparation stated they would repeat this preparation again compared with only 25 percent for the PEG group (P < 0.0001). Ninety-five percent of patients who received the NaP solution tolerated 100 percent of the solution compared with only 37 percent of the PEG group (P < 0.0001). For quality of cleansing, surgeons scored NaP as "excellent" or "good" in 87 compared with 76 percent after PEG (P = not significant). Rates of septic and anastomotic complications were 1 percent and 1 percent for NaP and 4 percent and 1 percent for PEG, respectively (P = not significant).

Conclusion: Both oral solutions proved to be equally effective and safe. However, patient tolerance of the small volume of NaP demonstrated a clear advantage over the traditional PEG solution.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial

MeSH terms

  • Colonic Diseases / surgery*
  • Elective Surgical Procedures*
  • Enema*
  • Humans
  • Patient Compliance
  • Phosphates*
  • Polyethylene Glycols*
  • Preoperative Care*
  • Prospective Studies
  • Rectal Diseases / surgery*
  • Single-Blind Method
  • Surveys and Questionnaires


  • Phosphates
  • Polyethylene Glycols
  • sodium phosphate