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Biomedical subjects

J A Windsor

Publications and source records attributed to J A Windsor.

At least 19 recordsLinked to original sources
PubMed2006

Clostridium perfringens infection of pancreatic necrosis: absolute indication for early surgical intervention.

It is generally accepted that the surgical treatment of pancreatic necrosis should be delayed as long as possible and after there is laboratory confirmation of infection, determined by image guided fine-needle aspiration. Two cases of severe necrotizing pancreatitis are presented where gas developed in the pancreatic bed, detected by CT scanning, within 2--4 days of the onset of symptoms. Bacteriology studies showed clostridium perfringens and other gram negative flora. The presence of retroperitoneal gas in this context is an absolute indication for early surgical intervention.

Aged↗
PubMed2005

The laparoscopic performance of novice surgical trainees: testing for acquisition, loss, and reacquisition of psychomotor skills.

BACKGROUND: It has been suggested that virtual reality (VR) might be useful for the selection of surgical trainees and the measurement of technical performance during preoperative training and retraining. This study was designed to determine whether it is possible to define and measure the acquisition, loss, and reacquisition of psychomotor skills in novice surgical trainees. METHODS: Novice surgical trainees (NSTs n = 10, junior surgical registrars with little or no prior experience with laparoscopic surgery) were tested and retested after 1 month using the Minimally Invasive Surgical Trainer-Virtual Reality. Two tasks were used: the simple task [stretch diathermy (SD)] and the more complex task [manipulation diathermy (MD)]. The score was derived from the time taken to complete the task and the number of errors that occurred. Acquisition is the difference between the first and last score of the first training session, loss is the difference in score that occurs between the last score of the first training session and the first score of the second training session, and reacquisition is the difference in the first and last scores of the second training session. A performance criterion level was defined for each task by testing a group of experienced laparoscopic surgeons (n = 10). Groups were compared using the nonparametric Wilcoxon signed rank test, with p < 0.05 considered to be significant. RESULTS: Acquisition of skill was found for five of 10 NSTs with the SD task and 10/10 for the MD task. As a group the NSTs achieved the criterion level from the outset with the SD task and exceeded it by the eighth attempt for the MD task. The best score was achieved with fewer attempts during the second training session for the SD but not the MD task. The defined parameters are expressed as mean percentage score +/- SD for the 10 NSTs and for each task. There was a 36% (+/- 26) acquisition for the SD task compared with 50% (+/- 4) for the MD task (Wilcoxon p = 0.241). There was a 23% (+/- 19) loss for the SD task compared with 81% (+/- 16) for the MD task (p < 0.005). There was a 20% (+/- 10) reacquisition for the SD task compared with 54% (+/- 7) for the MD task (p < 0.005). The mean scores were greater for the more complex task (MD), which was more useful in discriminating between the individual trainees and the two training sessions. CONCLUSIONS: It is possible to use VR to define the acquisition, loss, and reacquisition of psychomotor skills in individual NSTs and to compare them with a predefined performance criterion level. This study defines parameters that will be useful in repeated training sessions of NSTs in the preoperative phase of training and during retraining.

Clinical Competence↗
PubMed2004

Peritoneal gallstones following laparoscopic cholecystectomy: incidence, complications, and management.

BACKGROUND: Gallstone spillage during laparoscopic cholecystectomy (LC) is a common intraoperative event. Although gallstones left in the peritoneal cavity were initially considered harmless, a significant number of complications have been reported. Our aim was to quantify the likelihood, and to document the range, of subsequent complications. METHODS: A Medline search from 1987 to January 2003 was performed. Articles with more than 500 LCs that quantified the frequency of complications due to peritoneal gallstones were reviewed, as were representative case studies of different stated complications. RESULTS: Six studies, covering 18,280 LCs, were found. The incidence of gallbladder perforation was 18.3%, that of gallstone spillage was 7.3%, and that of unretrieved peritoneal gallstones was estimated to be 2.4%. There were 27 patients with complications. The likelihood of a complication when gallstone spillage occurred was 2.3%, which increased to 7.0% when unretrieved peritoneal gallstones were documented. CONCLUSION: Spilt gallstones have a small but quantifiably real risk of causing a wide range of significant postoperative problems.

Abscess↗
PubMed2001

Students' evaluation of surgical seminars in a teaching hospital.

AIM: To evaluate the surgical seminars given for medical students at Auckland University and factors affecting them, so as to define areas for improvement. METHODS: A confidential questionnaire was completed by fourth-year medical students for each surgical seminar they attended during an academic year. The seminars were repeated four times during the year. The questionnaire consisted of five statements relating to whether the seminar was stimulating, problem- oriented, patient-centred, evidence-based and interactive. The students rated each statement on a 7-point scale. RESULTS: 556 questionnaires evaluating 28 clinical teachers were collected. A generalized linear model showed that the clinical teachers (F=4.16, P = 0.0001), the attachment (F=4.39, P=0.005) and the interaction between the seniority and institute (F=6.38, P=0.019) had a significant effect on the rating of the seminars. University consultants and hospital registrars had the highest overall least-squares mean, followed by hospital consultants, while university lecturers had the lowest overall least-squares mean (5.56, 5.4, 5.18, and 4.36, respectively). Ratings for problem-oriented approach improved over the studied period, while ratings of evidence-based and patient-centred approaches remained lower. University consultants and hospital registrars had the best patient-centred approach compared with hospital consultants and university lecturers (least-squares means 5.52, 5.4, 5.01, 4.18, respectively). Hospital registrars showed the best interactive ability ratings (least-squares mean 5.51) while university lecturers had the least stimulating seminars (least-squares mean 4.46). CONCLUSIONS: Surgical seminars which were introduced to cover surgical topics had acceptable ratings in each of the teaching domains, although there is a need for improvement in the patient-centred and evidence-based approaches.

Clinical Competence↗
PubMed2001

Plasma amylin concentration is related to the severity of intestinal ischemic injury in rats.

BACKGROUND: Previous work has demonstrated that intestinal ischemia increases plasma amylin concentration. This study examined the relationship between the degree of intestinal ischemia injury and plasma amylin in an experimental rat model. METHODS: Wistar rats were divided into a control group (n = 6); a sham-operated group (n = 9); and 3 intestinal ischemia-reperfusion groups (n = 8 in each), which underwent clamping of the superior mesenteric artery for either 15, 30, or 45 minutes followed by 15 minutes of reperfusion. Samples were then collected for intestinal histology and measurement of amylin, insulin, and glucose. RESULTS: There was a positive correlation between the histologic score of the intestinal injury and the measured plasma amylin concentration (R = 0.48, P =.007). The median plasma concentration of amylin was 62 pmol/L (range, 42-97 pmol/L) in the 30-minute intestinal ischemia group and 58 pmol/L (42-86 pmol/L) in the 45-minute intestinal ischemia group. Both these groups were increased compared with the sham-operated group (29 pmol/L; range, 22-57 pmol/L; P <.001 and P <.005, respectively) and the control group (28 pmol/L; range, 26-42 pmol/L; P <.001 and P <.0005, respectively). The median plasma concentration of insulin in the 30-minute intestinal ischemia group was 4230 pmol/L (range, 1360-5770 pmol/L), which was increased compared with both the control group (950 pmol/L; range, 550-1510 pmol/L; P <.005) and the sham-operated group (720 pmol/L; range, 280-4180 pmol/L; P<.005). There were no differences between any of the other groups either for glucose, insulin, or amylin. CONCLUSIONS: Plasma amylin concentration is related to the severity of intestinal ischemic injury.

Amyloid↗
PubMed2000

Metabolic management of severe acute pancreatitis.

The metabolic management of severe acute pancreatitis involves early identification of patients with severe pancreatitis, aggressive fluid resuscitation, organ support, and careful monitoring in an intensive care environment. Recent evidence has helped to define the roles of enteral feeding, prophylactic antibiotics, endoscopic retrograde cholangiopancreatography, computed tomography, and fine-needle aspiration for bacteriology. The most difficult decision in the management of these patients is whether surgery is required and which of the complementary approaches to necrosectomy and drainage is appropriate. Key metabolic events in the acinar cell, pancreas, and intestines are now being unraveled, as is the basis for the systemic manifestations and organ dysfunction associated with pancreatitis. This gives hope for the development of more specific metabolic interventions, which will likely target the maintenance of intestinal integrity and function, preservation of pancreatic microcirculation, and balanced modulation of the inflammatory response.

Acute Disease↗
PubMed2000

Severity of acute pancreatitis: a multivariate analysis of oxidative stress markers and modified Glasgow criteria.

BACKGROUND: It is unknown whether measurement of markers of oxidative stress can improve the prediction of severity of acute pancreatitis. METHODS: Consecutive patients admitted with a diagnosis of acute pancreatitis were divided into mild (n = 62) and severe (n = 23) groups based on the Atlanta classification. Plasma oxidative stress markers were measured within 24 h of admission and included ascorbic acid (endogenous antioxidant), protein carbonyl (a marker of protein oxidation), thiobarbituric acid reactive substances (a marker of lipid peroxidation) and myeloperoxidase (a neutrophil enzyme that produces oxidants). Canonical correlation analysis was used to describe the relationship between these markers and the modified Glasgow criteria. Canonical variate analysis was used to define the best variables that could discriminate mild and severe pancreatitis. RESULTS: There was a significant correlation between markers of oxidative stress and the modified Glasgow criteria (first canonical correlation 0.69, P < 0.0001, Wilk's lambda test). Blood urea, serum albumin and white cell count were the best variables that discriminated mild and severe acute pancreatitis, and all were better than the oxidative stress markers. CONCLUSION: The markers of oxidative stress were highly correlated with the severity of pancreatitis. They are unlikely to be better than the modified Glasgow criteria in predicting it.

Acute Disease↗
PubMed2000

Laparoscopic anti-reflux surgery in New Zealand: a trend towards partial fundoplication.

BACKGROUND: The advent of laparoscopic anti-reflux surgery has generated considerable debate regarding the best technique. The present study was undertaken to determine the trends and current technique in laparoscopic anti-reflux surgery in New Zealand. METHODS: A confidential nationwide postal survey was sent to all general surgeons in New Zealand; it was repeated after a month, and followed up with a telephone prompt, if necessary. RESULTS: Of the 146 questionnaires sent out, 126 were returned (response rate: 86%), and 104 were excluded (no anti-reflux surgery performed (n = 96); surgeon retired (n = 5); paediatric surgeon (n = 3)). The number of operations performed by the 22 (16%) adult general surgeons who had performed laparoscopic anti-reflux surgery increased 4.6 times from 1991 to 1997 (474 open and 1218 laparoscopic operations). The median number of cases per surgeon was 30 (range: 5-300). In 1997 there were 208 (60%) total fundoplications (TF) and 135 (40%) partial fundoplications (PF) performed. Variations in the technique of TF included the Nissen-DeMeester (10 surgeons), the Nissen-Rosetti (nine surgeons), division of short gastric vessels (10 surgeons), and routine cruroplasty (14 surgeons). A PF had never been performed by six surgeons, was preferred by six surgeons, and four other surgeons were performing it more often. Variations in the technique of PF included posterior (12 surgeons) and anterior (four surgeons) forms. CONCLUSION: There is significant variation in the technique of laparoscopic anti-reflux surgery in New Zealand. A TF is preferred by 16 surgeons, but there appears to be a trend towards PF among the more experienced surgeons.

Data Collection↗
PubMed2000

Protein carbonyl measurements show evidence of early oxidative stress in critically ill patients.

OBJECTIVE: To determine whether there is evidence of oxidative injury in patients who are critically ill with severe sepsis or major trauma, by measuring protein and lipid oxidation products. DESIGN: A prospective, observational study. SETTING: Critical care unit at a university teaching hospital. PATIENTS: Twenty-two patients with severe sepsis (Acute Physiology and Chronic Health Evaluation II score 15-34) and eight patients with major trauma (Injury Severity Score 26-50). INTERVENTIONS: Plasma and bronchoalveolar lavage fluid was collected regularly during the first 10 days after trauma or onset of sepsis. Both fluids were analyzed for protein carbonyl concentrations as a measure of protein oxidation and thiobarbituric acid-reactive substances as a measure of lipid peroxidation. Myeloperoxidase concentrations were measured as an index of neutrophil activation. MEASUREMENTS AND MAIN RESULTS: Protein carbonyl concentrations were initially highly elevated compared with those in healthy adults in the plasma of both patient groups. They fell significantly within the first few days but remained above control values. Protein carbonyl concentrations were also high initially in bronchoalveolar lavage fluid and fell significantly with time. Thiobarbituric acid-reactive substances were not increased in plasma, and varied over a wide concentration range in lavage fluid. Myeloperoxidase activity reached micromolar levels in the lavage fluid when corrected for dilution, and was significantly higher in the plasma of the sepsis patients who subsequently died. There was a strong correlation between carbonyl concentrations in lavage fluid and plasma, and between protein carbonyls, thiobarbituric acid-reactive substances and myeloperoxidase in the lungs. CONCLUSIONS: Our results provide evidence of oxidation occurring early in severe sepsis and major trauma patients, with protein carbonyl measurements providing a sensitive index of this process. High protein carbonyl concentrations in plasma as well as bronchial aspirates indicate that oxidation is not restricted to the lungs. The correlation between oxidative measures and myeloperoxidase concentrations in the lung indicates that neutrophil oxidants could be responsible for the injury.

APACHE↗
PubMed2000

Caerulein-induced pancreatitis in Wistar rats.

We describe a refined model of intravenous caerulein-induced pancreatitis by using osmotic infusion pumps in the conscious unrestrained Wistar rat. The volume of caerulein required for the 6-h infusion is loaded into PE-55 catheter tubing attached to an Alzet (Alza Corporation, Palo Alto, CA) implantable osmotic pump that has been primed with saline. The technique has reliably induced mild edematous pancreatitis, which we verified histologically. Our refined model has the advantages of unrestrained animals, reduced animal handling and acclimation, and decreased cost.

Animals↗
PubMed1999

Plasma von Willebrand factor and intestinal ischaemia-reperfusion injury in rats.

The purpose of this study was to determine whether plasma von Willebrand factor concentrations are correlated with the degree of intestinal ischaemia-reperfusion injury. Forty-six anaesthetised adult Wistar rats were divided into five groups. The sham-operated group (S, n=10) had laparotomy and isolation of the superior mesenteric artery without clamping. Three ischaemia-reperfusion groups (n=10 in each) had clamping of the superior mesenteric artery for 15, 30, and 45 minutes, respectively, and reperfusion for 15 minutes. A control group (C, n=6) had direct puncture of the heart to sample blood. Mean arterial pressure was measured continuously. Blood was collected at the end of the study to measure von Willebrand factor. The small bowel injury was graded histologically. There was a significant systemic hypotension after declamping in all ischaemia-reperfusion groups, which had a high negative correlation with the histological score (R=-0.46, F=10.1, p<0.003, simple linear regression). Plasma von Willebrand factor was significantly elevated in the three ischaemia-reperfusion groups compared with the control group but not significantly different from the sham-operated group (mean von Willebrand factor concentration (SEM): 156 (29), 283 (29), 295 (25), 381 (44), and 366 (40)% in C, S, ischaemia-reperfusion 15, ischaemia-reperfusion 30, and ischaemia-reperfusion 45 groups, respectively). The concentration of von Willebrand factor was not correlated to the histological score (R=0.22, F=1.83, p<0.2) or the degree of hypotension after the removal of the clamp (R=-0.22, F=1.8, p<0.2, simple linear regression). This study shows that von Willebrand factor concentration does not correlate with the degree of intestinal ischaemia-reperfusion injury. It is unlikely that von Willebrand factor can be used as a predictor of disease severity.

Animals↗
PubMed1999

Phrenoesophageal ligament re-visited.

The phrenoesophageal ligament, attaching the esophagus to the diaphragm, has been given little emphasis in anatomy teaching. This study was undertaken to examine the macroscopic and microscopic structure of the phrenoesophageal ligament. The results indicate that the ligament is a distinct structure bridging the space between the esophageal wall and the margins of the esophageal hiatus. This ligament appears to arise from both the endothoracic fascia and the transversalis fascia and is composed of abundant collagen and elastic lamellae. Toward the wall of the esophagus, the ligament divides into a prominent upper leaf and an ill-defined lower leaf before inserting into the wall of the esophagus. Histological study reveals that the ligament has a substantial and deep insertion into the wall of the esophagus. It appears that the ligament plays an important role in anchoring the lower esophagus and maintaining gastroesophageal competence.

Cadaver↗
PubMed1999

Early ascorbic acid depletion is related to the severity of acute pancreatitis.

BACKGROUND: Ascorbic acid (AA) is an important endogenous antioxidant in plasma and has been shown to be decreased at the time of hospital admission in patients with acute pancreatitis. The aim of this study was to determine whether plasma AA concentration continues to decrease after admission and whether the extent of decrease is related to the severity of pancreatitis. METHODS: Consecutive patients with mild (n = 62) and severe (n = 23) acute pancreatitis had plasma AA concentration measured on the day of recruitment and on days 2 and 5 by high-performance liquid chromatography. RESULTS: The plasma AA concentration in patients with acute pancreatitis was significantly less than that in normal volunteers on days 0, 2 and 5 (P < 0.0001) and this was more marked in those with severe disease. There was a decrease in plasma AA concentration from day 0 to day 2 in patients with mild (P < 0.0001) and severe (P = 0.0005) pancreatitis, and from day 2 to day 5 in patients with severe pancreatitis (P = 0.023). CONCLUSION: Endogenous plasma AA continues to decrease over the first 5 days in hospital and the extent is related to the severity of acute pancreatitis. Presented to a meeting of the Australasian Surgical Research Society, Auckland, New Zealand, August 1995 and published in abstract form as Aust N Z J Surg 1996; 66: 243

Acute Disease↗
PubMed1999

Cholecystostomy: a review of recent experience.

BACKGROUND: Operative (OC) and percutaneous cholecystostomy (PC) are rarely undertaken for severe acute cholecystitis in patients in whom cholecystectomy is technically difficult or those with significant comorbidity. METHODS: A retrospective review was undertaken of the clinical, radiological and audit records of patients who were treated by cholecystostomy between 1988 and 1997 at Auckland Hospital. RESULTS: During the 10-year period 19 patients (eight male, 11 female; median age: 70 years, range: 35-90 years) had a cholecystostomy (OC: n = 8; PC: n = 11). The main indication for PC was high anaesthetic risk (10 cases). The main indication for OC was failed cholecystectomy (six cases). The patients undergoing PC tended to have a higher American Society of Anesthesiologists (ASA) grade than patients undergoing OC. The median delay from presentation to cholecystostomy was 3 days. More than half (11/19) were done during the 3 years (1992-94) after the introduction of laparoscopic cholecystectomy. The number of tube-related complications was significantly higher in PC patients (10/11 vs 3/8; P = 0.04), and the number of systemic complications was higher in the OC patients (4/8 vs 0/11; P = 0.018). The median duration of tube drainage was 17 days (range: 0-82 days) for OC and 24 days (range: 5-93 days) for PC. Four patients had stone extraction at the time of OC, including two who also had a partial cholecystectomy. One OC patient had stone extraction via the cholecystostomy tract. A cholecystectomy was performed in four patients. CONCLUSION: The data indicate that PC is a safe approach for high-risk patients. Operative cholecystostomy had a role following failed cholecystectomy. But PC might be safer in these patients if they could be identified pre-operatively.

Acute Disease↗
PubMed1999

Blunt abdominal trauma: comparison of ultrasonography and computed tomography in a district general hospital.

Ultrasonography has been proposed as a screening method for blunt abdominal trauma, but its specific role in comparison with other diagnostic modalities has yet to be defined. The aim of the present retrospective study was to compare the results of ultrasonography and CT of the abdomen in blunt trauma in a district general hospital. The hospital records of 25 patients who were admitted with blunt abdominal trauma to Southland Hospital, Invercargill, New Zealand, between January 1991 and November 1996 and who had both ultrasound and CT of the abdomen within 48 h of admission were reviewed. Ultrasound missed seven lesions in seven patients (7/25, 28%) compared with CT. Three of these were intestinal lesions that needed laparotomy. Ultrasound had a usefulness index of 1, 0.76, 0.72, 0.69 and 0, respectively, for detecting lesions of the kidneys, free intraperitoneal fluid, the liver, the spleen, and intestines. Although ultrasound can be used as an initial screening method for blunt abdominal trauma, CT is still the imaging modality of choice for detecting intra-abdominal lesions for stable patients in a district general hospital.

Abdominal Injuries↗
PubMed1999

The iliopubic tract: an important anatomical landmark in surgery.

A band of fascial thickening, termed the iliopubic tract, lies on the posterior aspect of the inguinal region and has been described in the surgical literature as playing an important role during herniorraphy. This study was undertaken to examine the gross and microscopic anatomy of the iliopubic tract in 12 cadavers. The results confirmed that the iliopubic tract can be readily identified as a thickening of the transversalis fascia running deep and parallel to the inguinal ligament. It attaches to the superomedial part of the pubic bone medially, but laterally its fibres fan out within the fascia transversalis and fascia iliaca without bony attachment to the iliac spines. In contrast to the inguinal ligament, the histological analysis of the iliopubic tract shows a high elastin to collagen ratio. The functional significance of this structure merits further study, but there is no doubt that it is important in many approaches to inguinal herniorraphy. For this reason it is considered that the iliopubic tract deserves greater emphasis in the anatomy teaching of the inguinal region.

Aged↗