Biomedical subjects
D J Leaper
Publications and source records attributed to D J Leaper.
Malignant neuroendocrine tumour of pancreas, Salmonella enteritidis cholangitis and pseudomembranous cholecystitis.
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Carcinoma of the gallbladder: a diagnostic challenge.
Since the introduction and availability of abdominal ultrasound and computed tomography, 38 patients have been admitted to the Department of Surgery, Queen Mary Hospital, University of Hong Kong with a subsequently confirmed histological diagnosis of carcinoma of the gallbladder. The majority of patients presented with abdominal pain, anorexia or weight loss, jaundice, and anaemia or an abdominal swelling. Abnormal liver function tests were found in 70-90%. Cholangiography, ultrasound and particularly computed tomography helped to confirm clinical suspicion when performed but 23 patients (61%) had an inaccurate diagnosis made before surgery. Operative intervention was only of benefit when the carcinoma was confined to the gallbladder (median survival after cholecystectomy alone 13 months; other procedures 2 months; P less than 0.01). Carcinoma of the gallbladder carries a poor prognosis but ultrasound and computed tomography can help select patients for appropriate treatment (surgery, endoscopic stenting, radiotherapy, chemotherapy) if clinical suspicion is raised.
Hypoxia and hypotension during endoscopy and colonoscopy.
Sixty-three patients undergoing oesophagogastroduodenoscopy (OGD) (n = 24) or proctosigmoidocolonoscopy (PSC) (n = 39) had continuous monitoring of arterial oxygen saturation (SaO2), pulse and mean blood pressure (BP). The degree of patient distress, duration, dose of sedative and details of the endoscope and operator were recorded. Marked hypotensive (greater than 40% fall in BP) and hypoxic (greater than 8% fall in SaO2) changes occurred in 13% and 17% of the overall group, respectively. There were no significant differences in fall in BP, SaO2 or pulse between the OGD and PSC groups. The dose of sedative was significantly related to the fall in SaO2 (P less than 0.001) but not to the fall in BP. The falls in both SaO2 and BP were related to the duration of the procedure (P less than 0.001, P = 0.03, respectively). There were no correlations between the degree of hypoxia or hypotension and the patient's age or previous medical history. Hypotension and hypoxia occur in both colonoscopy and OGD and are neither predictable nor usually recognizable clinically. Pulse oximetric and BP monitoring throughout gastrointestinal endoscopy are recommended for maximal safety.
Antiseptic toxicity to breast carcinoma in tissue culture: an adjuvant to conservation therapy?
Of 50 patients who had scrape cytology of the excision cavity after conservative surgery for breast carcinoma, 10 (20%) had malignant cells remaining in the cavity recognised by cytology. Of these patients, 18 had histological evidence of tumour at the resection margin, giving an accuracy of the cytology of 84%, a sensitivity of 56%, and a specificity of 100%. When assayed for cytotoxicity against a breast tumour cell line (MCF7) or human fibroblasts, chlorhexidine gluconate was the most effective of eight antiseptics or antitumour agents (100% cytotoxicity at a 1/10,000 dilution) in killing breast tumour cells and had 70% toxicity to human fibroblasts at the same dilution. Hydrogen peroxide appeared to be the most useful agent overall with 94% cytotoxicity to breast tumour cells with only a 12% cytotoxicity to human fibroblasts at a dilution of 1/1,000,000. We suggest that free malignant cells left in the cavity after conservative surgery for breast cancer may be a cause of local recurrence. They can be recognised by scrape cytology at operation and the topical use of antiseptics as cytotoxic agents may be beneficial and warrants further investigation.
Bowel preparation or not for elective colorectal surgery.
The importance of bowel preparation in elective colorectal surgery has often been stressed. We have surveyed the current practice of bowel preparation and chemoprophylaxis amongst surgeons in Wales and the south-west of England. From this we identified one surgeon who used no preoperative preparation and his results are reported in detail. One hundred consecutive colorectal cases were studied from one surgeon (J.M.P-T.). There was a 7% incidence of wound infection and one anastomosis leaked. None of these patients had mechanical bowel preparation but all had antibiotic chemoprophylaxis. Mechanical bowel preparation is usual in the UK. These results demonstrate that its importance as a factor in wound infection and anastomotic dehiscence may be overstated.
Further problems with thalidomide.
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Follow-up after colorectal cancer--current practice in Wales and south west England.
The necessity for follow-up after curative resection of colorectal cancer remains controversial. Many studies have failed to demonstrate the increase in survival which might be anticipated when detailed follow-up methods are used. In the United Kingdom no single policy has evolved. This study has examined, therefore, the current follow-up practice of a large group of British surgeons. Six per cent carried out no routine postoperative follow-up and there was great variation in the methods used and the regularity of visits. There is a need for a rational policy based on controlled studies to determine whether follow-up is of benefit to the patient and to identify the most effective methods.
Laser Doppler velocimetry and the measurement of colostomy blood flow.
Early colostomy closure leads to a high rate of fecal fistula formation which may be due to a poor blood supply. Laser Doppler flowmetry is a new method of measuring colonic blood flow. Blood flow in 17 colostomies has been measured at one week, median flux 28 units (range, 13 to 43) and in 12 colostomies more than eight weeks after formation, median flux 46 units (range, 35-56; P less than 0.002). Nine of the "mature" colostomies have been closed without a fecal fistula or other signs of anastomotic failure. Serial readings of colostomy blood flow were made at weekly intervals in another ten stomas over a period of two months. Blood flow increased over this time from a median of 19 units (range, 17 to 22) at one week to a median of 44 units (range, 39 to 48; P less than 0.002) at eight weeks. Laser Doppler flowmetry is a simple, noninvasive method of measuring colostomy blood flow and the findings support a clinical policy for delayed colostomy closure.
Gastric cancer following highly selective vagotomy.
A case of gastric cancer occurring seven years after a highly selective vagotomy is described. This operation may not be the appropriate choice for the surgical treatment of gastric ulcers and H2 blockers should be used with caution in these patients.
Polydioxanone suture in the gastrointestinal tract.
A randomized prospective trial was undertaken of polydioxanone suture (PDS) versus conventional suture material in 98 patients undergoing anastomoses in the gastrointestinal tract. Nine patients died within 6 months of surgery, one of these being related to an anastomotic leak. All other patients were followed up for between one and three and a half years. In 57 colonic anastomoses, 30 were randomized to a single layer of 2/0 (BPC) interrupted PDS and 27 to a single of 2/0 (BPC) interrupted silk. Follow up sigmoidoscopy and barium enemas were used to confirm the clinical suspicion of 6 benign anastomotic strictures, 5 of which occurred in the PDS group. At this stage, the colonic arm of the trial was discontinued because the 19% stricture rate with PDS was deemed unacceptable. In a second limb of the study, patients were randomized to two layers of 2/0 (BPC) continuous PDS or 2/0 (BPC) continuous chromic catgut. There were no significant differences in 32 gastric or small bowel anastomoses and in particular, no anastomotic strictures were apparent. The reasons for the high rate of stricture formation when using PDS for large bowel anastomoses are unclear. However, it would seem to be a suitable alternative to chromic catgut when confined to the stomach and small intestine.
Treatment of acute bacterial peritonitis: a trial of imipenem/cilastatin against ampicillin-metronidazole-gentamicin.
Imipenem/cilastatin at a dose of 0.5 g six hourly was compared to conventional combination therapy with ampicillin 0.5 g six hourly, metronidazole 0.5 g eight hourly and gentamicin 80 mg eight hourly (with dose adjustment by trough and peak serum levels) in the treatment of severe intra-abdominal infections. All antibiotics were given intravenously. Forty-five patients entered the trial. Of the 19 evaluable patients in the imipenem/cilastatin group, 16 were clinically cured with five microbiological successes and two failures. Of 24 evaluable patients in the combination group, 22 were clinically cured with one microbiological success and one failure. One patient in each group suffered an adverse effect. Patients in the I/C group tended to be older with more women and more severe infections. The origin of peritonitis was similar. I/C did not differ from combination therapy in efficacy or safety and was comparable in cost. However, I/C was easier to administer than combination therapy and there was no need for serum concentration monitoring.
A clinical and experimental study of colostomy blood flow and healing after closure.
Colostomy blood flow and healing have been studied in both man and rat. Laser Doppler velocimetry (LDV) was used to measure flow and showed a significant difference between colostomy blood flow measured at 1 week and at more than 8 weeks after fashioning (p less than 0.002). Hartmann colostomies were constructed in rats and closed at 3 or 6 weeks later. There was a correlation between distal colonic (stump) blood flow and anastomotic bursting pressures 3 days after closure in the 3-week group (r = 0.080; p less than 0.01). Colostomies closed at 6 weeks were significantly stronger than those closed at 3 weeks (p less than 0.02). Collagen concentration in proximal (stoma) colon was higher in the 6-week group compared with the 3-week group prior to anastomosis. There was also a fall in the proximal collagen after anastomosis in both 3- (p less than 0.01) and 6-week groups (p less than 0.01). Poor blood flow measured by LDV and colonic collagen concentration may predict poor healing after colostomy closure. LDV is a non-invasive technique with clinical application in this field.
Intraoperative antegrade lavage and anastomotic healing in acute colonic obstruction.
The management of acute distal colonic obstruction remains controversial. The advent of intraoperative colonic irrigation has allowed primary anastomosis to be performed in obstructed bowel. Fifteen patients, with acute distal obstruction due to carcinoma, diverticulitis or sigmoid volvulus were managed by primary resection and anastomosis. There were two leaks (14 percent) and the duration of operation was prolonged. In an experimental study of anastomotic healing after acute obstruction, intraoperative irrigation improved early anastomotic colonic collagen content (P less than 0.02) and perianastomotic proximal and distal collagen content (P less than 0.002, P less than 0.05). Intraoperative lavage is a useful technique to permit safer primary resection and anastomosis in obstructed colon.
A comparative trial between cefotetan and cephazolin for wound sepsis prophylaxis during elective upper gastrointestinal surgery with an investigation of cefotetan penetration into the obstructed biliary tree.
Cefotetan is a cephamycin antibiotic theoretically suited to prophylaxis of wound infection during upper elective gastrointestinal surgery. In a prophylaxis trial 100 patients undergoing this type of surgery were randomly allocated to receive 1g cefotetan or cephazolin iv at induction of anaesthesia. Cefotetan-treated patients had significantly fewer postoperative infections overall (P less than 0.05) and there were no wound infections recorded in this group. In a separate pharmacokinetic study the penetration of cefotetan into common bile duct bile and gallbladder wall was measured in a further six patients, all of whom had been jaundiced preoperatively. At the time of maximum risk concentrations of cefotetan in bile and biliary tissue as well as blood and wound fat were in excess of the minimum inhibitory concentration for the majority of relevant pathogens. Cefotetan appears to be equally or more effective than cephazolin and is a suitable alternative prophylactic agent in elective upper gastrointestinal surgery.
Antiseptic toxicity in wounds healing by secondary intention.
The effects of two commonly used antiseptics for chronic ulcer care, chloramine T and chlorhexidine, on the biochemical and histological parameters of healing have been examined. The antiseptics were compared with saline when applied to 10 mm skin defects on Sprague-Dawley rats. Chloramine T significantly delayed the production of collagen and prolonged the acute inflammatory response compared with saline. Chlorhexidine did not differ from saline. We conclude that hypochlorite antiseptics may adversely affect healing by secondary intention and the antibacterial and desloughing action of agents should be carefully balanced against their toxic effect.
The effect of antiseptics and topical antimicrobials on wound healing.
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