Background

Mechanical bowel preparation (MBP) has until recently been thought to be one of the most important factors to decrease infectious complications and prevent anastomotic dehiscence after elective colorectal surgery, but its value has been questioned [1, 2]. Several randomised studies [3–9] and meta-analyses [10–12] since the beginning of the 1990's have shown that omission of MBP does not increase the risk for anastomotic dehiscence or septic complications in colon surgery. In the largest, randomised multicenter trial performed we found that MBP did not lower the risk for cardiovascular, general infectious or surgical site complications [13].

The aim of this study was to compare the patients' experience and acceptance of preoperative MBP versus no preoperative MBP in elective colon surgery.

Methods

The study population was recruited from patients participating in the Swedish Mechanical Bowel Preparation Study comparing the outcome after elective open colon surgery with or without mechanical bowel preparation [13]. The study used central randomization with facsimile transmission to the randomisation centre. The allocation result was returned the same day. Stratification was made for each participating unit and the patients were randomised in blocs of permutation of four using computer generated random numbers. The participating surgeons did not know the size of the blocs. The inclusion criteria were: elective surgery for cancer, adenoma or diverticular disease, age 18–85 years, ASA (American Society of Anesthesiologists) Classification I-III, and life expectancy 6 months or longer.

At three units participating in the trial, patients were asked to complete a questionnaire having 39 questions, each with 3–10 answer alternatives. The questionnaire was designed using parameters previously validated to describe preoperative and postoperative experience.

Patients completed questionnaires preoperatively and on Days 1, 4 and 7. The questions and answer alternatives are described in Table 1 (preoperative) and Table 2 (postoperative). Comparisons were made between patients receiving mechanical bowel preparation (MBP group) and patients without mechanical bowel preparation (No-MBP group) prior to surgery. The planned number to be included in the study was 100 patients. Data were recorded in a protocol and stored in an electronic database at the study centre in Motala, Sweden.

Table 1 The Patient's experience preoperatively.
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Table 2 The Patient's experience postoperatively. Description of questionnaire
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The Local Ethics Committee approved the study.

Statistical analysis

The chi square test was used to test differences between categorical variables and the t-test or Mann-Whitney U-test for independent groups to test differences between continuous variables. Two tailed P-values < 0.05 were considered significant.

Results

One hundred and five patients were included in the study between February 2000 and March 2002. Sixty patients received MBP and 45 had no MBP. The groups were balanced regarding age, gender, BMI and diagnosis as shown in Table 3. MBP was accomplished with sodium phosphate in 28 patients, polyethylene glycol in 31 patients, and enema in one case.

Table 3 Demographic data and diagnosis
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Tolerability to bowel preparation

Four patients in the MBP group could not complete the intended MBP (two of these patients received sodium phosphate, and two polyethylene glycol). All four patients stated that the reason for not completing MBP was inability to drink the required amount of fluid. In addition, two patients mentioned nausea to be a problem.

Assistance with MBP (hospital staff or relative) was required by 30/58 (52%) of the patients in the MBP group. Sixteen per cent of patients in the MBP group reported more than 10 defecations the day before surgery.

Questionnaire results

Only three statistically significant differences were noted between the two groups (Table 1, 2): willingness to consider the same preoperative procedure again time to first bowel movement (p = 0.04) and degree of discomfort on day 4 postoperatively (p = 0.02). The response rate in the No-MBP group to the question about the willingness to consider the same preoperative procedure again was low (58%) compared to the response rate in the MBP group (95%) (P < 0.001), see Table 4. Patients in the No-MBP group had their first bowel movement earlier than patients in the MBP group, see Table 5. Patients in the No-MBP group experienced a higher degree of discomfort (but not pain or nausea) on the fourth postoperative day compared to patients in the MBP group. For details see Figures 1 2 3.

Table 4 Could you consider the same preoperative preparation again?
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Table 5 Time to first bowel movement
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Discussion

In this study we have shown that patients prefer not to have MBP, that the time to first postoperative bowel movement is shorter without MBP, and that patients not receiving MBP experienced more discomfort on the fourth postoperative day.

The response rate to the question concerning willingness to consider the same preoperative procedure again was significantly lower in the No-MBP group compared to the MBP group, 58 Vs 95%. This most likely reflects the fact that many patients without MBP thought (correctly) that they did not receive any "preoperative procedure". However, for patients answering this question those in the MBP group were less inclined to consider the same preoperative procedure again (30% vs. 65%).

Different methods for MBP exist, of which whole bowel irrigation with oral polyethylene glycol and sodium phosphate solutions are most commonly used according to recent studies [3, 4, 8, 14]. It has been shown that the patient acceptance is greater for sodium phosphate than for polyethylene glycol [15]. However, sodium phosphate is contraindicated in patients with renal or congestive heart failure due to its influence on electrolyte- and water balance which limits its use in many elderly patients.

Patients in the No-MBP group experienced a higher degree of abdominal discomfort on the fourth postoperative day than patients in the MBP group, but without any corresponding difference in perceived pain. One possible explanation for the inter-group difference is an earlier onset of bowel motility in the No-MBP group. The majority of patients in the No-MBP group had their first bowel movement on the third or fourth postoperative day compared to more than four days in the MBP group. Early bowel movement is compatible with accelerated rehabilitation and is thus an advantage [16].

The questionnaire used was designed for this study and was not validated prior to this study. The questions addressed to the patients were however chosen based on previous research [17–21].

Besides safety and patient preference there are economic issues to be addressed when deciding whether or not to change routines in preoperative bowel preparation. Our study showed that 52% of patients receiving MBP needed help from hospital staff or a relative. For many patients this requires admission to the surgical ward early the day before surgery, thereby increasing the workload on the personnel and the cost to society.

Conclusion

It has previously been shown that mechanical bowel preparation does not reduce the rate of complications in colon surgery. This report demonstrates that mechanical bowel preparation is considered unpleasant by many patients and that it delays the return of normal bowel movements. Both these findings increase the incentive to omit mechanical bowel preparation in elective colon surgery.

Figure 1
figure 1

Height of boxes represents median of experienced discomfort on Days 1, 4 and 7 postoperatively, measured as value on a ten point Numerical Rating Scale. Vertical bars represent inter-quartile range. P < 0.05 considered significant (t-test).

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Figure 2
figure 2

Height of boxes represents median of experienced nausea on Days 1, 4 and 7 postoperatively measured as value on a ten point Numerical Rating Scale. Vertical bars represent inter quartile-range. P < 0.05 considered significant (t-test).

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Figure 3
figure 3

Height of boxes represents median of experienced pain on Days 1, 4 and 7 postoperatively measured as value on a ten point Numerical Rating Scale. Vertical bars represent inter-quartile range. P < 0.05 considered significant (t-test).

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