Bowel preparation: comparing metabolic and electrolyte changes when using sodium phosphate/polyethylene glycol.

BACKGROUND: Many patients with various types of colonic pathology undergo invasive procedures that require mechanical bowel preparation. The most commonly used medications for bowel preparation include phosphate-containing drugs which are low cost and enable this procedure to be performed in an outpatient setting, as opposed to other medications, such as polyethylene glycol. Recent studies have suggested that freely using phosphate-containing drugs might lead to renal function impairment in a small group of patients. Despite this, many surgeons still use these drugs to prepare their patients. We conducted a comparative study to check the side effects of phosphate-containing drugs compared to polyethylene glycol when used for bowel cleansing. METHODS: We conducted a double blind prospective randomized study that included 40 patients undergoing surgery for colonic pathology, all of whom underwent bowel cleansing (20 with sodium phosphate and 20 with polyethylene glycol). During the perioperative course, electrolyte parameters were collected from serum and urine and compared between the two groups of patients. RESULTS: Changes in electrolyte and metabolic parameters were shown in both groups, but more prominently in patients prepared with sodium phosphate. In addition, early signs of renal function impairment appeared in this group. The differences in metabolic and electrolyte changes between the two groups were statistically significant. CONCLUSIONS: On the basis of this study, we propose that the wide use of phosphate-containing drugs for colonic preparation might be dangerous for the specific group of patients that is prone to develop renal failure or electrolyte abnormalities.

Detection and comparison of nitric oxide in clinically healthy horses and those with naturally acquired strangulating large colon volvulus.

The objective of the study was to determine whether nitric oxide (NO) is present in clinically healthy horses (control) under basal conditions, and if it increases secondary to naturally acquired strangulating large colon volvulus (affected). Eleven affected horses and 10 controls were studied. Jugular venous blood, abdominal fluid, and urine were collected. The NO concentrations were standardized to the creatinine concentration in the respective samples. A biopsy specimen collected from the large colon pelvic flexure at surgery was divided into subsections for processing for inducible nitric synthase (iNOS) and nitrotyrosine (NT) immunohistochemical staining and reduced nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemical staining. There were no significant differences in plasma, abdominal fluid, or urine NO concentrations between affected and control horses. There was a significant decrease in submucosal arteriolar and venular endothelium, submucosal plexus, mucosal leukocyte, mucosal and musclaris vasculature, and myenteric plexus NADPH diaphorase staining in affected versus control horses. There was a significant increase in iNOS staining in mucosal leukocytes and vasculature in affected versus control horses. Other than a greater number of positively stained mucosal leukocytes in affected horses, there were no significant differences between affected and control horses for NT staining. The presence of NADPH diaphorase staining in the endothelium and submucosal neurons suggests endothelial and neuronal NOS are present under basal conditions in the large colon of horses. Increased iNOS and NT staining in mucosal leukocytes of affected horses suggests involvement of the NO pathway in large colon volvulus. The reasons for the lack of a significant difference in plasma, abdominal fluid, and urine NO concentrations between affected and control horses are unknown.

Neonatal encephalopathy with a pungent body odour.

A neonate had transient unexplained bleeding into the gut, severe encephalopathy, and an abnormal pungent body odour. An inherited metabolic defect was excluded. The malodour was due to methanethiol and hydrogen sulphide, identified in urine. These sulphur compounds may have contributed to encephalopathy. Colonic bacteria were the probable source.

Urinary tissue factor activity in colorectal disease.

Procoagulant activity (PCA) in normal urine has been recognized for over 50 years. Although tissue factor (TF) is produced by certain tumours, and is increased in both tumour-associated macrophages and blood monocytes, the possibility that it might also be increased in urine has not been studied in patients with cancer. We have measured urinary PCA in hospital controls without inflammatory or neoplastic disease (n = 79), in patients with rheumatoid arthritis (n = 8), inflammatory bowel disease (n = 19), colorectal cancer (n = 70) and in patients undergoing colonoscopy (n = 50). Urinary PCA was higher (P less than 0.001) in patients with colorectal cancer and inflammatory bowel disease than controls or patients with rheumatoid arthritis. Fourteen (88 per cent) out of 16 colonoscopy patients subsequently found to have carcinoma or inflammatory bowel disease had levels above the control upper quartile, compared with 8 (24 per cent) out of 34 with normal colonoscopy (P less than 0.001). TF inhibitors confirmed the nature of the PCA and Western blotting studies indicated a urinary TF molecular weight of approximately 38,000. These studies provide further evidence of abnormal haemostasis in malignancy and suggest that determination of urinary TF may provide a useful screening test in patients undergoing colonoscopy.

Detection of occult colovesical fistula by the Bourne test.

The value of different diagnostic tests in the detection of colovesical fistulas was studied in 28 surgically proven cases seen during the last 10 years at the University of Michigan, Ann Arbor. Etiologies were diverticulitis (19), Crohn disease (three), postradiation therapy (four), previous trauma (one), and bladder carcinoma (one). The fistulas were demonstrated by barium enema in 10 of 20 patients and by cystography in eight of 26. Cystoscopy was diagnostic in 11 of 25 patients and sigmoidoscopy in four of 24. Methylene blue test was positive in five of six patients, and in one patient given a charcoal enema the material appeared in the urine. The Bourne test, consisting of radiography of the centrifuged urine samples obtained immediately after a nondiagnostic barium enema, was positive in nine of 10 patients. In seven of these 10 patients, the Bourne test was the only positive evidence of an otherwise occult colovesical fistula later proven at surgery.