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Biomedical subjects

A V Pollock

Publications and source records attributed to A V Pollock.

At least 37 records · Page 2Linked to original sources
PubMed1987

Microbiologic prediction of abdominal surgical wound infection.

We compared two methods of estimating parietal bacterial contamination during abdominal operations. Duplicate swabs were taken from the subcutaneous tissues at the end of 817 operations; one was transported to the Department of Microbiology in Stuart's thioglycollate medium and the other immediately incubated in Robertson's cooked meat broth in the operating room suite and subsequently subcultured. The broth cultures revealed significantly more isolations of potentially pathogenic bacteria and more accurately predicted the likelihood of wound infection. In particular, when visceral cultures were positive, broth culture of wound swabs predicted a major wound infection rate of 0% when sterile, 4.8% when a single pathogenic species was cultured, and 10.1% when two or more were cultured. The corresponding figures for thioglycollate-transported swabs were 1.0%, 10.5%, and 12.9%. We conclude that broth cultures of parietal swabs allow accurate identification of patients at risk of infection from bacterial contamination of the wound during operation.

Abdomen↗
PubMed1987

Pre-operative assessment of fitness score.

Death within 30 days or survival after a major operation depends on three things: the severity of the disease and the operation, the technical proficiency of the surgeon and the ability of the patient to withstand both disease and operation. The first of these can be estimated by reference to published figures, the second can only be guessed at and the third has in the past been a matter of subjective judgement. With the aim of producing an objective assessment of the likelihood of survival, we have constructed a score system comprising 26 items including age, chronic disease and acute presenting disease. These items are each given a weight of 1 to 4 and the total fitness score for any patient ranges from 0 (fit) to 10 (unlikely to survive). We have validated this score prospectively in 1517 consecutive patients undergoing emergency or elective major abdominal operations (excluding appendicectomies and hernia repairs). In 492 operations in which the patient scored 0 or 1, one patient died (0.2 per cent); in 290 with scores of 2 or 3, one died (0.3 per cent); in 313 with scores of 4 or 5, five died (1.6 per cent). It was when the score rose to 6 or over that the chances of survival progressively declined: 16 died of the 105 patients who scored 6 (15.2 per cent) as did 74 of the 191 who scored 7 or 8 (38.7 per cent) and 70 of the 126 who scored 9 or 10 (55.6 per cent). We now use the score as part of our audit and enquire particularly closely into the death of any patient with a pre-operative score of less than 6.

Abdomen↗
PubMed1987

Peroperative lavage of the obstructed left colon to allow safe primary anastomosis.

A series of 44 patients with complete or partial left-colon obstruction underwent laparotomy and intraoperative colonic lavage. Irrigation was unsuccessful in three, the operation being concluded by a Hartmann resection. In the remaining 41, the achievement of an empty colon allowed primary anastomosis after resection of the obstructing lesion. Seven patients (17.1 percent) died, none of dehiscence of the colorectal anastomosis, although minor anastomotic leaks occurred in four. The median postoperative hospital stay was 12 days. Two patients developed peritonitis (one fatal) from leakage of ileal contents when the irrigating catheter was introduced through an ileotomy and retained postoperatively, and this aspect of the technique is not recommended. The operation offers a single-stage alternative for patients with unprepared or ill-prepared bowels who require resection of left-colon lesions. The results compare favorably with the authors' previous experience of two- or three-stage resections (in-hospital mortality rate, 42 percent).

Aged↗
PubMed1987

The inadequacy of published random control trials of antibacterial prophylaxis in colorectal surgery.

Fifty-six papers published between 1979 and 1986 that tested regimens of antibacterial bowel preparation before elective colorectal operations were studied using a numerical score devised for assessing publications of random control clinical trials. A maximum score of 100 was allotted: 50 for 15 aspects of design, 30 for ten aspects of analysis, and 20 for eight aspects of presentation. The 56 papers scored from 33 to 89, (mean, 61.6, standard deviation, 11.9). Only 13 (23 percent) reached a score of more than 70. The most frequent errors in design were the use of placebos in the control group (27 percent) and faulty methods of randomization (36 percent). Errors in analysis resulted in penalization of more papers than any other aspect; these included the almost universal omission of confidence limits, confusion of exclusions and withdrawals (46 percent), not recording the fate of withdrawals (80 percent) and incorrect use of statistical tests (55 percent). Ten papers reported results showing important clinical differences that did not achieve statistical significance, but only two mentioned the Type II error. Defects in presentation were less frequently encountered; the most common were inaccessibility of raw data (66 percent), lack of sufficient information to allow replication of methods (43 percent), and the drawing of firm conclusions from shaky data (50 percent). It was particularly disappointing that no evidence of improvement in the standard of these reports over the seven years studied was found.

Anti-Bacterial Agents↗
PubMed1986

Fluid sequestration: an early indicator of mortality in acute pancreatitis.

Complete daily intake and output charts were available for 218 patients with acute pancreatitis. The patients were divided into three groups according to the relation between fluid intake and output. In 105 patients in whom there was negligible fluid sequestration (daily output within 2 litres of intake) there were six deaths (5.8 per cent). In 69 patients the daily fluid intake exceeded the output by 2 litres or more but this imbalance lasted for 48 h or less; six patients died (8.7 per cent). The remaining 44 patients sequestered 2 litres or more of fluid per day for more than 48 h or until death. Thirty-eight patients in this group died (86.4 per cent). Fluid sequestration of 2 litres or more per day, and lasting longer than 48 h, is an accurate and simple predictor of mortality in acute pancreatitis. In this study it had a sensitivity of 76 per cent and a specificity of 96 per cent. The predictive value of a positive result was 86 per cent and of a negative result 93 per cent (efficiency 92 per cent).

Acute Disease↗
PubMed1986

The prediction of abdominal surgical wound infection: the value of an enrichment broth for initial culture of operative parietal swabs.

At the conclusion of 817 abdominal operations, duplicate swabs were taken from the subcutaneous tissues for microbiological examination; one swab was transported to the laboratory in Stuart's thioglycollate medium and the other immediately incubated in Robertson's cooked meat broth. The latter method resulted in significantly more isolations of potentially pathogenic bacteria than the former, (31% compared with 17%, P less than 0.001). Immediate culture in broth with subsequent subculture allowed more accurate prediction of patients at risk of wound infection; using this method we found a 1:3 likelihood of wound infection with a 5% chance of severe infection when a single pathogenic species was cultured, and a 1:2 likelihood of wound infection with a 10% chance of severe infection when two or more pathogenic species were cultured. Transport of swabs in thioglycollate medium, in contrast, detected fewer patients with parietal contamination and showed a 1:5 likelihood of wound infection when the swab was sterile and a 1:2 chance when one or more than one pathogenic species was cultured.

Abdomen↗
PubMed1986

Single-dose antibiotic prophylaxis of abdominal surgical wound infection: a trial of preoperative latamoxef against peroperative tetracycline lavage.

A randomized controlled clinical trial was undertaken in 542 consecutive emergency and elective abdominal operations, with one group of patients receiving tetracycline peritoneal and wound lavage and the other a single intravenous injection of 1 g latamoxef at induction of anaesthesia. Seventy-five patients were withdrawn because no potentially contaminated hollow viscus was opened, and a further 36 because they could not be assessed for wound infection. Of the remaining 431 patients, 212 received latamoxef resulting in 5 major and 8 minor wound infections in hospital; another 4 minor infections occurred at home (total incidence 8.0%). In the tetracycline group (n = 219) there were 7 major and 19 minor wound infections in hospital and 10 minor infections later (total incidence 16.4%). This is significantly higher than the rate with latamoxef (P = 0.012). Monitoring of operative and postoperative bleeding revealed no evidence (except in one doubtful case) of excessive bleeding associated with the use of a single dose of latamoxef. It is concluded that single-dose preoperative latamoxef is more effective than peroperative tetracycline lavage for the prevention of wound infections after potentially contaminated abdominal operations.

Abdominal Muscles↗
PubMed1986

Towards no incisional hernias: lateral paramedian versus midline incisions.

A prospective randomized controlled clinical trial is reported which compares midline with lateral paramedian incisions in relation to the development of incisional hernias at one year. Of 431 patients randomized, 329 were available for assessment one year later. Two patients suffered burst abdomen, both being in the lateral paramedian group. Twenty-two incisional hernias occurred, 2 in the lateral paramedian group and 20 in the midline group (P less than 0.001). Of the two types of incision, the lateral paramedian incision takes longer to perform, requires a longer incision, rarely results in dehiscence, and does confer protection against incisional hernia.

Adolescent↗
PubMed1986

The prediction of incisional hernias by radio-opaque markers.

On the hypothesis that incisional defects occur soon after operation but the resulting hernia may not be diagnosed until months or years later, we attached three to five pairs of stainless steel haemostatic clips to the cut edges of the anterior aponeurosis during the closure of 59 major laparotomy incisions and X-rayed the abdomen one month later. Three patients were withdrawn and the remaining 56 were examined with special reference to incisional herniation at their six-month follow-up visit. The senior author subsequently arranged a series of extra clinics for surviving patients up to three years later (median 30 months after operation). He had no knowledge of the results of the abdominal X-rays when assessing whether or not the patient had a hernia. Six patients were found to have incisional hernias, and correlation with the measurements on the one-month X-rays showed separation of pairs of clips ranging from 12-70 mm (median 40). Three of the six hernias were discovered within seven months, the remaining three at 13, 28 and 29 months. In contrast none of the 50 patients without incisional hernias had more than 9 mm of separation of any pair of clips on the one-month X-ray. We conclude that the origins of incisional hernias can be traced back to events during the first month after operation and that they are not the result of later weakening of a well-healed laparotomy wound.

Hernia, Ventral↗
PubMed1985

A score system for evaluating random control clinical trials of prophylaxis of abdominal surgical wound infection.

We devised 33 rules for the evaluation of random control trials (RCT) and used them to assess 56 RCTs listed in Index Medicus during 1980-82 on antibiotic prophylaxis of surgical wound infection. We asked 15 questions about design and conduct, 10 about analysis and 8 about presentation. Out of a maximum score of 100 only 16 papers scored over 70, the highest being 89 and the lowest 34. Defects in presentation were not common, and 17 papers scored over 90 per cent. Defects in analysis included the incorrect use of statistical tests and ignoring the Type II error in 'negative' trials; only 13 papers scored over 70 per cent. Defects in design and conduct included transgressions of ethical principles, inappropriate regimens, ill-defined end points and biased randomization or assessment; only 20 papers scored over 70 per cent. We conclude that there is room for improvement in the performance of RCT and that the application of the 33 rules would be helpful not only to researchers but also to editors and referees of scientific journals, and to their readers.

Abdomen↗
PubMed1985

Suction drainage of the gallbladder bed does not prevent complications after cholecystectomy: a random control clinical trial.

Some surgeons drain the gallbladder bed routinely, some selectively and some not at all. We aimed to clarify this confusion by entering 155 consecutive patients undergoing emergency and elective cholecystectomy without exploration of the common bile duct into a random control clinical trial. In 78 patients a 3 mm suction drain was left in the gallbladder bed and in 77 the abdomen was closed without drainage. There were no withdrawals, one death (in the drainage group) from myocardial infarction and one intraperitoneal abscess complicating postoperative pancreatitis (in the no-drainage group). Other events studied were postoperative pyrexia, wound infection, respiratory tract infection and duration of hospital stay. In none of these did the two groups differ either clinically or statistically. We conclude that drainage or non-drainage of the gallbladder bed must remain a matter of individual preference.

Aged↗