Randomized controlled trial of preoperative oral carbohydrate treatment in major abdominal surgery.

BACKGROUND: Major surgery is associated with postoperative insulin resistance which is attenuated by preoperative carbohydrate (CHO) treatment. The effect of this treatment on clinical outcome after major abdominal surgery has not been assessed in a double-blind randomized trial. METHODS: Patients undergoing elective colorectal surgery or liver resection were randomized to oral CHO or placebo drinks to be taken on the evening before surgery and 2 h before induction of anaesthesia. Primary outcomes were postoperative length of hospital stay and fatigue measured by visual analogue scale. RESULTS: Sixty-nine and 73 patients were evaluated in the CHO and placebo groups respectively. The groups were well matched with respect to surgical procedure, epidural analgesia, laparoscopic procedures, fasting period before induction and duration of surgery. Postoperative changes in fatigue score from baseline did not differ between the groups. Median (range) hospital stay was 7 (2-35) days in the CHO group and 8 (2-92) days in the placebo group (P = 0.344). For patients not receiving epidural blockade or laparoscopic surgery (20 CHO, 19 placebo), values were 7 (3-11) and 9 (2-48) days respectively (P = 0.054). CONCLUSION: Preoperative CHO treatment did not improve postoperative fatigue or length of hospital stay after major abdominal surgery. A benefit is not ruled out when epidural blockade or laparoscopic procedures are not used. REGISTRATION NUMBER: ACTRN012605000456651 (http://www.anzctr.org.au).

Stapled versus handsewn methods for ileocolic anastomoses.

BACKGROUND: Ileocolic anastomoses are commonly performed for right-sided colon cancer and Crohn's disease. The anastomosis may be constructed using a linear cutter stapler or by suturing. Individual trials comparing stapled versus handsewn ileocolic anastomoses have found little difference in the complication rate but they have lacked adequate power to detect potential small difference. To our knowledge, this is the first systematic review specifically investigating ileocolic anastomosis. OBJECTIVES: To compare outcomes of ileocolic anastomoses performed using stapling and handsewn techniques. The hypothesis tested was that the stapling technique is associated with fewer complications. SEARCH STRATEGY: MEDLINE, EMBASE, Cochrane Colorectal Cancer Group specialised register SR-COLOCA, Cochrane Library were searched for randomised controlled trials comparing use of a linear cuter stapler with any type of suturing technique for ileocolic anastomoses in adults from 1970 to 2005. Abstracts presented to the following society meetings between 1970 and 2002 were handsearched: American Society of Colon and Rectal Surgeons, the Association of Coloproctology of Great Britain and Ireland, European Association of Coloproctology. SELECTION CRITERIA: Randomised controlled trials comparing use of linear cutter stapler (isoperistaltic side to side or functional end to end) with any type of suturing technique in adults. DATA COLLECTION AND ANALYSIS: Eligible studies were selected and their methodological quality assessed. Relevant results were extracted and missing data sought from the authors. RevMan 4.2 Analysis version 1.0.5 was used to perform meta-analysis when there were sufficient data. Sub-group analyses for cancer and inflammatory bowel disease as indication for ileocolic anastomoses were performed. MAIN RESULTS: After obtaining individual data from authors for studies that include other anastomoses, six trials (including one unpublished) with 955 ileocolic participants (357 stapled, 598 handsewn) were included. The three largest trials had adequate allocation concealment. Stapled anastomosis was associated with significantly fewer anastomotic leaks compared with handsewn (S=5/357, HS=36/598, OR 0.34 [0.14, 0.82] p=0.02). One study performed routine radiology to detect asymptomatic leaks. For the sub-group of 825 cancer patients in four studies, stapled anastomosis led to significant fewer anastomotic leaks (S=4/300, HS=35/525, OR 0.28 [0.10, 0.75] p=0.01). There were too few Crohn's disease patients to perform sub-group analysis. All other outcomes: stricture, anastomotic haemorrhage, anastomotic time, re-operation, mortality, intra-abdominal abscess, wound infection, length of stay, showed no significant difference. AUTHORS' CONCLUSIONS: Stapled functional end to end ileocolic anastomosis is associated with fewer leaks than handsewn anastomosis.

Oral water soluble contrast for the management of adhesive small bowel obstruction.

BACKGROUND: Adhesions are the leading cause of small bowel obstruction. Gastrografin transit time may allow for the selection of appropriate patients for non-operative management. Some studies have shown when the contrast does not reach the colon after a designated time it indicates complete intestinal obstruction that is unlikely to resolve with conservative treatment. When the contrast does reach the large bowel, it indicates partial obstruction and patients are likely to respond to conservative treatment. Other studies have suggested that the administration of water-soluble contrast is therapeutic in resolving the obstruction. OBJECTIVES: To determine the reliability of water-soluble contrast media and serial abdominal radiographs in predicting the success of conservative treatment in patients admitted with adhesive small bowel obstruction.Furthermore, to determine the efficacy and safety of water-soluble contrast media in reducing the need for surgical intervention and reducing hospital stay in adhesive small bowel obstruction. SEARCH STRATEGY: The search was conducted using MESH terms: ''Intestinal obstruction'', ''water-soluble contrast'', "Adhesions" and "Gastrografin". The later combined with the Cochrane Collaboration highly sensitive search strategy for identifying randomised controlled trials and controlled clinical trials. SELECTION CRITERIA: 1. Prospective studies were included to evaluate the diagnostic potential of water-soluble contrast in adhesive small bowel obstruction.2. Randomised clinical trials were selected to evaluate the therapeutic role. DATA COLLECTION AND ANALYSIS: 1. Studies that addressed the diagnostic role of water-soluble contrast were critically appraised and data presented as sensitivities, specificities and positive and negative likelihood ratios. Results were pooled and summary ROC curve was constructed.2. A meta-analysis of the data from therapeutic studies was performed using the Mantel -Henszel test using both the fixed effect and random effect models. MAIN RESULTS: The appearance of water-soluble contrast in the colon on an abdominal X ray within 24 hours of its administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 0.97, specificity of 0.96. The area under the curve of the summary ROC curve is 0.98. Six randomised studies dealing with the therapeutic role of gastrografin were included in the review, water-soluble contrast did not reduce the need for surgical intervention (OR 0.81, p = 0.3). Meta-analysis of four of the included studies showed that water-soluble contrast did reduce hospital stay compared with placebo (WMD= - 1.83) P<0.001. AUTHORS' CONCLUSIONS: Published literature strongly supports the use of water-soluble contrast as a predictive test for non-operative resolution of adhesive small bowel obstruction. Although Gastrografin does not cause resolution of small bowel obstruction there is strong evidence that it reduces hospital stay in those not requiring surgery.

Meta-analysis of oral water-soluble contrast agent in the management of adhesive small bowel obstruction.

BACKGROUND: Adhesions are the leading cause of small bowel obstruction. Identification of patients who require surgery is difficult. This review analyses the role of Gastrografin as a diagnostic and therapeutic agent in the management of adhesive small bowel obstruction. METHODS: A systematic search of Medline, Embase and Cochrane databases was performed to identify studies of the use of Gastrografin in adhesive small bowel obstruction. Studies that addressed the diagnostic role of water-soluble contrast agent were appraised, and data presented as sensitivity, specificity, and positive and negative likelihood ratios. Results were pooled and a summary receiver-operator characteristic (ROC) curve was constructed. A meta-analysis of the data from six therapeutic studies was performed using the Mantel-Haenszel test and both fixed- and random-effect models. RESULTS: The appearance of water-soluble contrast agent in the colon on an abdominal radiograph within 24 h of its administration predicted resolution of obstruction with a pooled sensitivity of 97 per cent and specificity of 96 per cent. The area under the summary ROC curve was 0.98. Water-soluble contrast agent did not reduce the need for surgical intervention (odds ratio 0.81, P = 0.300), but it did reduce the length of hospital stay for patients who did not require surgery compared with placebo (weighted mean difference--1.84 days; P < 0.001). CONCLUSION: Published data strongly support the use of water-soluble contrast medium as a predictive test for non-operative resolution of adhesive small bowel obstruction. Although Gastrografin does not reduce the need for operation, it appears to shorten the hospital stay for those who do not require surgery.

A novel model used to compare water-perfused and solid-state anorectal manometry.

BACKGROUND: Anal pressures are commonly measured using water-perfused and solid-state manometers. We constructed a dynamic model of the anus to compare the agreement and reproducibility of the two types of manometers. METHODS: The model system was constructed using a pig anorectum together with an inflatable bowel sphincter. The pig anorectum was mounted on a jig and the sphincter was inserted external to the internal sphincter. The sphincter pressure was adjusted over the range 20 to 185 mmHg. At each of 24 constant sphincter pressures, triplicate readings were carried out with both manometers. The first measurement by each method was used for the comparison. The replicate measurements were used to calculate measures of repeatability for each method. RESULTS: Measurements by the two manometers were highly correlated (r=0.97). Measurements by the solid state manometer were higher than the water-perfused manometer by 8.1+/-12.2 mmHg (mean+/-SD). Precision (coefficient of variation) for the solid-state manometer (2.8%) was better than for the water-perfused manometer (8.3%). CONCLUSIONS: The new model of the anal canal shows promise as a tool for assessing physiological interventions. The solid-state manometer has many advantages over the water-perfused manometer, providing more consistent measurements at clinically relevant pressures.

Evaluation of knowledge and anxiety level of patients visiting the colorectal pelvic floor clinic.

OBJECTIVE: Discussing defaecating disorders is difficult for patients and many view anal physiology investigations (ultrasound, manometry, electromyography and pudendal nerve studies) as distasteful. This pilot study sought to assess whether present information sheets supplied to patients and the visit to the colorectal Pelvic Floor Clinic itself influenced patients' knowledge and anxiety. PATIENTS AND METHODS: Thirty Pelvic Floor Clinic patients from Auckland City Hospital were included. Each patient filled in a questionnaire before and after the clinic. This included objective questions about their knowledge of the structure and function of the pelvic floor and satisfaction with and understanding of the information sheet. Both visual analogue scale (VAS) and multiple choice questions (MCQ) were used. Their subjective and objective knowledge were compared. Anxiety was assessed on a visual analogue anxiety scale (VAAS). Results were expressed as VAS scores or percentage correct and relationships were tested using Fisher's Exact test and paired T-test. RESULTS: Subjective knowledge increased in 93% of the patients. The doctor's explanation led to a greater increase in subjective knowledge than the information sheet (35/100 mm, P<0.001 and 10/100 mm, P=0.01, respectively). Subjective improvement in knowledge did not however, translate into an increase in objective knowledge (P=0.63). The information sheet was read by 87% of the patients. The information sheet had reduced anxiety only in 23% of the patients and increased in 10%. Anxiety levels were not significantly influenced by the information sheet, but reduced significantly by the clinic visit in 87% of patients (P<0.001). The mean anxiety level reduced from 44/100 to 12/100 after the clinic visit. CONCLUSION: Anxiety levels are high in those visiting the Pelvic Floor Clinic. It appears that it is the interaction with the doctor that has a profound influence on anxiety levels and subjective knowledge rather than written information.

Long-term results of the anterior Délorme's operation in the management of symptomatic rectocele.

PURPOSE: Although the results of surgery for symptomatic rectocele seem satisfactory initially, there is a trend toward deterioration with time. This study was designed to assess the long-term outcome of Anterior Délorme's operation for rectocele. METHODS: Questionnaires were sent to all females who had Anterior Délorme's operation performed in Auckland between 1990 and 2000. The questionnaires included obstructed defecation symptoms and a validated fecal incontinence severity index questionnaire and fecal incontinence quality of life questionnaire. Preoperative and postoperative obstructed defecation symptoms and incontinence score were compared. RESULTS: A total of 150 females (mean age, 56 (range, 30-83) years) who had an Anterior Délorme's operation for a rectocele were identified. One hundred seven patients (71.5 percent; mean age, 56 years) completed the questionnaire. Median follow-up was four (range, 2-11) years. The number of patients with obstructed defecation reduced from 87 preoperatively to 23 postoperatively using Rome II criteria (P < 0.0001). Postoperatively there was a reduction in the number of patients with each of the symptoms of obstructed defecation from 83 to 27 for straining, 87 to 33 for incomplete emptying, 64 to 14 for feeling of blockage, 41 to 10 for digitation (P < 0.0001 for all). The median incontinence score reduced from 20 of 61 preoperatively to 12 of 61 postoperatively (P = 0.0001). CONCLUSIONS: In patients with symptomatic rectocele, Anterior Délorme's operation provides long-term benefit for patients with obstructed defecation and leads to a significant improvement of incontinence scores.

Oral water soluble contrast for the management of adhesive small bowel obstruction.

BACKGROUND: Adhesions are the leading cause of small bowel obstruction. Most adhesive small bowel obstructions resolve following conservative treatment but there is no consensus as to when conservative treatment should be considered unsuccessful and the patient should undergo surgery. Studies have shown that failure of an oral water-soluble contrast to reach the colon after a designated time indicates complete intestinal obstruction that is unlikely to resolve with conservative treatment. Other studies have suggested that the administration of water-soluble contrast is therapeutic in resolving the obstruction. OBJECTIVES: The aims of this review are:1. To determine the reliability of water-soluble contrast media and serial abdominal radiographs in predicting the success of conservative treatment in patients admitted with adhesive small bowel obstruction.2. To determine the efficacy and safety of water-soluble contrast media in reducing the need for surgical intervention and reducing hospital stay in adhesive small bowel obstruction. SEARCH STRATEGY: The search was conducted using MeSH terms: ''Intestinal obstruction'', ''water-soluble contrast'', "Adhesions" and "Gastrografin", and combined with the Cochrane Collaboration highly sensitive search strategy for identifying randomised controlled trials and controlled clinical trials. SELECTION CRITERIA: 1. Prospective studies (to evaluate the diagnostic potential of water-soluble contrast in adhesive small bowel obstruction);2. Randomised clinical trials (to evaluate the therapeutic role). DATA COLLECTION AND ANALYSIS: 1. Studies addressing the diagnostic role of water-soluble contrast were critically appraised and data presented as sensitivities, specificities and positive and negative likelihood ratios. Results were pooled and summary receiver operating characteristic (ROC) curve was constructed. 2. A meta-analysis of the data from therapeutic studies was performed using the Mantel -Haenszel test using both the fixed effect and random effects model. MAIN RESULTS: The appearance of water-soluble contrast in the caecum on an abdominal radiograph within 24 hours of its administration predicts resolution of an adhesive small bowel obstruction with a pooled sensitivity of 0.96, specificity of 0.96. The area under the curve of the summary ROC was 0.98. Four randomised studies dealing with the therapeutic role of Gastrografin were included in the review, water-soluble contrast did not reduce the need for surgical intervention (odds ratio 1.29, P = 0.36). Meta-analysis of two studies showed that water-soluble contrast reduced hospital stay compared with placebo (weighted mean difference = - 2.58) P = 0.004. AUTHORS' CONCLUSIONS: Published literature strongly supports the use of water-soluble contrast as a predictive test for non-operative resolution of adhesive small bowel obstruction. Although Gastrografin does not cause resolution of small bowel obstruction, it does appear to reduce hospital stay.

Waiting time thresholds: are they appropriate?

BACKGROUND: The introduction of health reforms in New Zealand included the setting of an arbitrary waiting time threshold of 6 months for surgery. The aim of the present study was to investigate the differences in waiting times for different diagnoses in elective general surgery, and the interplay between diagnoses and waiting time thresholds. METHODS: A survival curve analysis of 918 patients placed on the elective general surgical waiting lists was conducted. This was undertaken in a tertiary level hospital in New Zealand before the implementation of the waiting time thresholds. The difference between diagnoses of time waited for elective surgery (plotted on survival curves), and hazard function for patients waiting at 180, 360 and 540 days, was investigated. RESULTS: Survival curves for malignancy, cholelithiasis, hernias and anorectal disease were different on log-rank test (P < 0.001). Those with a diagnosis of malignancy show that at 180 days the hazard function was 0.0049 but by 360 days had dropped to zero. With hernias and anorectal disease, the drop to zero appeared to be delayed until 540 days; however, the confidence intervals at 360 days included zero. In the case of cholelithiasis, the hazard functions indicate surgery occurring until 540 days. CONCLUSIONS: There are different waiting time thresholds for different surgical illnesses. Setting a universal waiting time for elective surgery is not supported.

Identification of the fascia propria by magnetic resonance imaging and its relevance to preoperative assessment of rectal cancer.

UNLABELLED: If rectal cancer does not penetrate the fascia propria of the rectum and the rectum is removed with the fascial envelope intact (extrafascial excision), then local recurrence of the cancer will be minimal. Modern imaging techniques have identified a fascial plane surrounding the rectum and mesorectum, and it has been suggested that this is the fascia propria. The aim of this study was to identify whether this plane is the rectal fascia propria and whether tumor invasion through this fascia can be identified preoperatively. METHODS: Two separate experiments were performed: 1) pelvic magnetic resonance imaging was performed before and after dissection and marking of the plane of extrafascial dissection of the rectum of a cadaver; and 2) magnetic resonance imaging was performed in 43 rectal cancer patients preoperatively. Two radiologists independently reported the depth of tumor invasion in relation to the fascia propria. The tumors were resected by extrafascial excision, and a pathologist independently reported the relation of the tumor to the fascia propria. RESULTS: The marker inserted in the extrafascial plane showed that the plane visualized on pelvic magnetic resonance imaging was the fascia propria dissected in extrafascial excision of the rectum. The magnetic resonance imaging detected tumor penetration through the fascia propria with a sensitivity of 67 percent, a specificity of 100 percent, and an accuracy of 95 percent. CONCLUSION: The surgical fascia propria can be identified on preoperative magnetic resonance imaging in patients with rectal cancer. Tumor invasion through this fascia can be detected on magnetic resonance imaging. This method of assessment offers a new way to select those patients who require preoperative radiotherapy.

In vitro analysis of periprosthetic strains following total knee arthroplasty.

Clinical case studies have disclosed certain risk factors associated with periprosthetic fracture in elderly patients. How the mechanical strength of the distal femur is changed by total knee arthroplasty (TKA) has not been elucidated. Using elderly cadaveric femora, this study evaluated both periprosthetic strains and associated fracture patterns arising from an in vitro simulation of a fall onto the distal femur. The data showed a significant increase in anterior and posterior mechanical strain following TKA. Neither stemless nor stemmed versions of two cemented Howmedica prostheses (Rutherford, NJ) reduced distal femur strains to baseline values. However, neither produced a disproportionate frequency of periprosthetic fractures. Although not formally evaluated herein, bone geometry/density may contribute more profoundly to the occurrence of periprosthetic fracture than the implants tested.

Results of extrafascial excision and conventional surgery for rectal cancer at Auckland Hospital.

BACKGROUND: Recent studies have suggested that local recurrence rates following rectal cancer surgery are reduced if the mesorectum is removed intact within its fascia propria. The present study aims to compare the outcomes of conventional surgery for rectal cancer and surgery in which the rectum and mesorectum are removed by the technique of extrafascial excision (EFE). METHODS: All patients undergoing surgery for rectal cancer at Auckland Hospital from 1980 to 1996 were identified. Demographic, tumour, operation, outcome, survival and follow-up data were obtained from patient charts, New Zealand (NZ) Death Registry, death certificates and the NZ Electoral Roll. Complication rates, recurrence rates, overall and cancer-free survival and treatment costs were calculated for each group. RESULTS: A total of 262 patients had curative surgery (138 had conventional surgery, 124 had EFE). The groups were similar with respect to age, sex, operation performed and Dukes' stage. There was no difference in complication rates between the groups. Mean follow-up was 7 years in survivors. Twenty-nine conventional-surgery (21%) and eight EFE (6%) patients developed local pelvic recurrence. The 5-year actuarial local recurrence rates were 30% and 10%, respectively (P = 0.0006). The 5-year overall survival was 54% for conventional surgery and 60% for EFE (P = 0.23). The 5-year cancer-free survival was 63% for conventional surgery and 74% for EFE (P = 0.02). Average initial costs were NZ$15,717 and NZ$15,158 for conventional surgery and EFE, respectively. The average cost of local recurrence was an additional NZ$10,471. CONCLUSIONS: The present study adds further support to the growing evidence that excision of the mesorectum within an intact fascial envelope reduces local recurrence rates after surgery for rectal cancer. There appears to be an associated improvement in cancer-free survival. Complication rates and cost were not increased in the patients having EFE.

The anatomical relationship between the posterior interosseous nerve and the supinator muscle.

Understanding the anatomical relationships in the region of the supinator muscle is crucial in limiting surgical morbidity. The course, length, and muscular innervations of the posterior interosseous nerve, as well as a detailed dissection of the supinator muscle, were described and recorded in 31 specimens from 16 adult cadavers. In our study, the radial nerve bifurcated into the posterior interosseous nerve and superficial radial nerve 8.0 +/- 1.9 cm distal to the lateral intermuscular septum. The bifurcation of the radial nerve occurred 3.6 +/- 0.7 cm proximal to the leading edge of the supinator, with the posterior interosseous nerve exiting the supinator muscle 3.8 +/- 0.9 cm distal to the proximal margin. The arcade of Frohse was membranous in 68% of our specimens and tendinous in 32%. The supinator had one semicircular head or layer in 71% of specimens and 2 distinct heads or layers, as defined by diverging muscle fibers, in 29%. With 2 heads, or layers, the superficial layer extended to the lateral epicondyle while the deep layer extended to the ulna, below the radial notch.

Misconceptions about the colonic J-pouch: what the accumulating data show.

INTRODUCTION: Since 1986 when the colonic J-pouch-anal anastomosis was first described, it has gained increasing acceptance as the operation of choice for low rectal cancer surgery. However, there still exist several misconceptions about its use, namely anastomotic complications, alterations in anorectal physiology, and functional outcome. METHODS: All relevant articles derived from MEDLINE databases from 1986 to the present were reviewed. Emphasis was placed on reviewing the features that are claimed to make the colonic J-pouch-anal anastomosis superior to a straight anastomosis. RESULTS AND CONCLUSIONS: The colonic J-pouch has a role in ultra-low rectal cancer surgery, with an apparent reduction in the incidence of anastomotic leaks and reduced bowel frequency. Continence is unchanged and defecatory difficulties can be reduced by constructing a small pouch (< or =5 cm).

On-the-table colonic lavage.

Single-stage surgery is an acceptable option in the modern management of many acute colonic conditions. Anastomosing unprepared colon is a major concern. A technique is described that allows on-the-table colonic lavage to be performed without contamination of the abdominal cavity.

Priority access criteria for elective cholecystectomy: a comparison of three scoring methods.

AIM: To compare two priority access criteria scoring methods for elective cholecystectomy, with a score based on clinical judgement obtained using a linear analogue scale. METHODS: Patients placed on the waiting list for elective laparoscopic cholecystectomy between June and October 1997 were prioritised using the three methods. RESULTS: Data were obtained for 22 patients. The distributions of scores were different but there was a significant correlation between them. However, limits of agreement analysis demonstrated little agreement between them with a difference of +/- 30 points (out of a 100) between scores obtained with each method. CONCLUSION: The proposed methods for establishing priority access to elective cholecystectomy are poor tools, require validation and bear little relation to expert clinical judgement.

Generic surgical priority criteria scoring system: the clinical reality.

AIMS: To assess the 'generic surgical priority criteria' (GSPC) introduced into Auckland Hospital by the Northern Division of the Transitional Health Authority in 1997 and compare it with a score based on clinical judgement obtained using a linear analogue scale (LAS). METHODS: From the time of introduction in June 1997 all patients being placed on the general surgical waiting list have been scored using both the GSPC and the LAS. After two months the scores given to 209 patients were reviewed and compared. Correlation and limits of agreement analysis were performed for grouped data, cancer and benign groups. RESULTS: The data showed wide variation and poor agreement between the surgeons' clinical judgement in assessing priority for surgery and the score patients obtained using the GSPC. CONCLUSION: The GSPC has poor diagnostic discrimination as it failed to identify reliably a cancer diagnosis as high priority, with benign diagnoses scoring consistently higher. This highlights the need for clinical involvement in designing priority criteria and for formal validation of such tools.

Cellular potassium depletion predisposes to hypokalaemia after oral sodium phosphate.

BACKGROUND: Oral sodium phosphate has become an attractive alternative to polyethylene glycol for colonic cleansing preparatory to elective colorectal surgery. Its use, however, has been associated with hypokalaemia. The authors of the present study tested the hypothesis that patients with cellular depletion of potassium are at significant risk for hypokalaemia with oral sodium phosphate bowel preparation. METHODS: In 23 patients, total body potassium was measured by whole-body counting and intracellular water volume was measured by bioimpedance analysis before oral sodium phosphate bowel preparation. Patients were divided into those whose serum potassium fell to 3.5 mmol/L or lower (Group 1) and those whose did not after sodium phosphate treatment (Group 2). RESULTS: The fall in serum potassium concentration over the period of oral sodium phosphate administration was significantly negatively correlated with intracellular potassium concentration measured prior to administration (r = -0.65, P = 0.0009). In Group 1, serum potassium concentration fell from 4.1+/-0.1 (standard error of the mean (SEM)) mmol/L to 3.2+/-0.1 mmol/L (P < 0.0001) while in Group 2 there was no significant change in this concentration (4.0+/-0.1 vs 3.9+/-0.1 mmol/L) as a result of sodium phosphate treatment. Intracellular potassium concentration prior to administration of sodium phosphate was significantly lower in Group 1 (117+/-9 mmol/L vs 143+/-7 mmol/L, P < 0.05). CONCLUSIONS: Caution should be exercised when treating patients with oral sodium phosphate who are considered to be cellularly depleted of potassium. These patients are at risk of hypokalaemia after this treatment.