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Biomedical subjects

R H West

Publications and source records attributed to R H West.

At least 19 recordsLinked to original sources
PubMed1999

Abdominal surgery in the older Crohn's population.

BACKGROUND: The surgical literature perceives that the elderly cohort of Crohn's patients may have increased risk with surgery. METHODS: A retrospective review and prospective database analysis of all patients with histologically proven Crohn' s disease who had a laparotomy at a single Sydney teaching hospital were performed. The last laparotomy of each patient was included in the analysis for morbidity and mortality to assess whether an older cohort was at an increased risk. RESULTS: A total of 156 patients had 298 laparotomies for histopathologically proven Crohn's disease. The frequency distribution of age at last laparotomy was bimodal, and the statistically determined cut-off age between younger and older cohorts was 55 years. Thirty-three patients were older than 55 years. There was no difference in duration of symptoms before first diagnosis (older, 17 months vs younger, 25 months), previous number of Crohn's operations (42.4 vs 39.8%), or duration of known Crohn's disease. Isolated large bowel disease was more common in the elderly cohort (42.4 vs 18.7%, chi2 = 8.09, P < 0.01). Small bowel and ileocaecal resections were more common in the younger cohort (72.4 vs 51.6%, chi2 = 5.19, P < 0.025). There was one death in each cohort (overall mortality 1.3%) and anastomotic leak rates (defined as the number of leaks per number of patients with anastomoses), were 4.3% (older) vs 5.3% (younger) despite frank sepsis present in 21.2% of all subjects at the time of surgery. The older group had more cardiac (18.2 vs 0.8%, P < 0.001) and respiratory complications (18.2 vs 2.4%; P = 0.0003) and a longer mean but not median postoperative hospital admission. CONCLUSIONS: In conclusion, clinical features and presentation are similar in the older and younger Crohn's patients having a laparotomy. However, in the older patient there is a greater likelihood of large bowel disease, ileocaecal resection is done less commonly, there is a higher risk of minor cardiopulmonary postoperative complications, but with similar mortality and anastomotic leak rates to the younger patient.

Abdomen↗
PubMed1998

Detection of persistent vegetative bacteria and amplified viral nucleic acid from in-use testing of gastrointestinal endoscopes.

Hospital-acquired infection attributed to inadequate decontamination of gastrointestinal endoscopes prompted an in use evaluation of recommended procedures. Specimens were obtained from the internal channels of 123 endoscopes before, during and after decontamination by flushing with saline and brushing with a sterile brush, and examined for vegetative bacteria by broth and plate culture. Four endoscopy units were tested; the chemical disinfectants used were: 2% glutaraldehyde in Centres 1 and 2 (automated) and Centre 3 (manual); peracetic acid in Centre 4 (automated). Samples from patients in Centre 1 with known chronic hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1) infection were also examined for viral nucleic acid by ultracentrifugation, nucleic acid extraction, reverse transcription (for RNA) and polymerase chain reaction (PCR). No persistent vegetative bacteria were found following standard manual cleaning and disinfection for 20 min in 2% glutaraldehyde in Centres 2 and 3 (N = 37). At Centre 1, while plate culture yielded no growth, 34% of samples (10/29) grew vegetative bacteria in broth culture after cleaning and disinfection for 20 min in 2% glutaraldehyde. Investigation revealed an error in manual cleaning; no bacteria were detected in 37 samples taken after this was corrected. At Centre 4, despite the use of peracetic acid as a sterilant, three out of 20 (15%) of post decontamination samples grew bacteria; one contained persistent bacteria. HBV and HCV PCR analysis detected viral nucleic acid in three out of four and four out of six samples from viraemic patients undergoing endoscopy in Centre 1 during the period of improper manual washing. After proper cleaning was instituted, samples from nine out of nine HCV viraemic patients were negative. HIV RNA was detected in five of 14 samples taken from endoscopes after use on HIV positive patients but all post decontamination samples were negative. Detection of bacteria in washes from endoscope channels is a useful warning of a breakdown in decontamination practice. Inadequate brushing of internal channels may result in persistent HCV and HBV viral nucleic acid, the significance of which is not clear. These results reinforce the importance of adequate manual cleaning of endoscopes before chemical disinfection.

Bacteria↗
PubMed1998

Detecting sterilization effects on packaging.

There must be evidence to show that medical devices and their packaging are compatible with the sterilization process that is used. Here, results from analysis of some medical-grade polystyrene packaging highlight the benefits offered by current surface analysis techniques.

Durable Medical Equipment↗
PubMed1996

Establishment of an in-use testing method for evaluating disinfection of surgical instruments using the duck hepatitis B model.

Nosocomial transmission of hepatitis B virus (HBV), associated with interventional procedures, has been attributed to its survival on improperly decontaminated instruments. To date, guidelines for chemical disinfection of potentially contaminated heat-sensitive instruments have been based largely on extrapolation of data from in-vitro disinfectant testing. Direct infectivity testing has not been possible for HBV because of the lack of a practical culture assay or susceptible experimental animal model. In this study the related duck hepadnavirus was used to simulate in-vivo transmission of a HBV during surgery, and to evaluate the effectiveness of 2% glutaraldehyde disinfection of surgical laparoscopes. Multiple laparoscopic liver biopsies were performed on 'biohazardous' duck hepatitis B (DHBV) positive ducks. Laparoscopes were then subjected to different disinfection regimes using 2% glutaraldehyde, and residual infectivity tested by placing their tips into the peritoneal cavities of uninfected four-day-old ducklings. Direct transmission of DHBV occurred in all ducks when laparoscopes were not washed. Rinsing with water lowered the transmission rate to 64% and no infection transmission occurred after 5 min of contact time with the disinfectant. In contrast, previous in-vitro studies had shown complete viral inactivation after a shorter period of disinfection. It is postulated that the longer inactivation time observed in our study may be a result of surface interactions of virus and instrument, interfering with disinfectant access or activity. Tests of instrument surface samples for viral DNA by the polymerase chain reaction (PCR) did not correlate with transmission of virus infection in vivo. PCR is an inappropriate test for evaluating the efficacy of disinfectant action despite its sensitivity. This in use method will allow testing of other decontamination procedures and their effectiveness on more complex surgical instruments.

Animals↗
PubMed1996

Surface analysis of packaging materials. Part I.

The surface composition and chemistry of medical device packaging can affect critical characteristics, such as biocompatibility, of the enclosed device. Seal and interface failure of packaging can threaten the long-term sterility of the devices it holds. Techniques to examine all these factors are introduced in Part I of this two-part article, with particular reference to adhesion failure and additive migration.

Equipment Safety↗
PubMed1996

Surface analysis of packaging materials. Part II.

The surfaces of medical device packaging can affect critical characteristics of the enclosed devices, such as biocompatibility and sterility. Techniques to evaluate surface modification and contamination in packaging applications are described in the second part of this two-part article.

Equipment Contamination↗
PubMed1995

Surface analysis of biomedical devices.

Modern surface analysis methods are highly effective tools in the development and manufacture of biomedical devices. Improvements in the performance of surface analysis techniques and sample handling are shown to have extended their value throughout device development. The application of these techniques and key improvements in their capabilities are discussed in the light of possible future regulatory requirements, which could include auditing of the surface chemistry of devices during manufacture, packaging, and storage.

Equipment and Supplies↗
PubMed1995

Outcome of patients with haemorrhagic shock: an indicator of performance in a trauma centre.

The survival rate of patients admitted to the Royal Prince Alfred Hospital (RPAH) from the central Sydney area with a major injury has improved since regionalization of trauma services in early 1992. This improvement has been attributed to education, better hospital care and changing trauma epidemiology. This study was conducted to assess whether the outcome of patients admitted with haemorrhagic shock had improved. This is proposed as a more subtle indicator of hospital performance than overall survival rates. A prospective before and after study was carried out comparing outcome in the 18 months preceding 1 January 1992 with that in the subsequent 18 months. Entry criteria to the study included all primary retrievals from the central Sydney area to RPAH with injury severity scores (ISS) > 15. Outcomes were compared generally and in those who were in a state of haemorrhagic shock (systolic blood pressure < or = 90 mmHg) on arrival at the emergency department. Three hundred and eight patients were entered into the study. Stratification showed similar numbers, demographic features and mechanisms of injury in the two groups. Forty patients were in a state of haemorrhagic shock on admission. The overall mortality was reduced from 31% to 11% (P < 0.001) over the two phases of the study. The mortality from blood loss in the 40 shocked patients fell from 10/25 in the first period to 2/15 (P = 0.07) in the latter. These improved survival rates were felt to reflect the value of the educational and organizational initiatives introduced following designation of the hospital as a trauma centre.

Adult↗
PubMed1994

Surgical management of breast cancer. Experience of the Central Sydney Area Health Service Breast X-ray Programme, 1988-1991.

OBJECTIVE: To review the breast cancers detected in the first three years of the Central Sydney Area Health Service Breast X-ray Programme, their histopathology and their surgical management within the program. DESIGN: Between March 1988 and March 1991, women screened in the program who had a suspicious lesion were referred for surgical assessment at the program assessment centre at Rachel Forster Hospital. These women were seen by staff of the assessment centre, including program surgeons, and were then treated at either Rachel Forster Hospital or Royal Prince Alfred Hospital. Features examined include cancer detection, clinical findings, diagnostic techniques, histopathological diagnosis of the lesions and surgical management. RESULTS: One hundred and eight cancers were detected in 105 women, with 59% of the cancers impalpable. The benign to malignant ratio was 1.0:1.5. Twenty-four cancers (22%) were ductal carcinoma-in-situ with or without microinvasion, and 84 (78%) were frankly invasive. Of the 86 axillary dissections, 63 (73%) showed no node involvement on histological examination. At the time of diagnosis, 27% of the women had axillary node involvement proven by axillary dissection. The overall mastectomy rate was 58%. Radiotherapy, chemotherapy and tamoxifen were used in both stage I and stage II disease. CONCLUSION: The surgical management of cancers reflects similar findings reported in other screening programs. There is an increasing trend towards breast conservation surgery and up to 90% of the women in this study present with favourable prognostic factors for long term survival.

Adult↗
PubMed1993

Impact of pedestrian injury on inner city trauma services.

This report describes the epidemiology of pedestrian injury in four inner metropolitan local government areas of Sydney. These data were obtained from the Roads and Traffic Authority of New South Wales. The spectrum of injury and clinical outcome was defined in patients with an Injury Severity Score (ISS) > 15 admitted from the study area, during a 1 year period, to the four inner metropolitan teaching hospitals. The incidence of pedestrian death was 3.3 times the state average of 32/10(6)/year. An average of 235 pedestrians, injured in the study area, were hospitalized each year during the period 1987-89. On average 24 pedestrians died each year, seven at the scene and 17 in hospital. Fifty patients (ISS > 15) were admitted to the four teaching hospitals during a 1 year period 1990-91. Forty-five were adults and five children. Multiplicity of injury was seen in 68% of patients. The pelvis and lower extremities were involved in 70%, the head in 66% and chest in 42%. The hospital mortality rate was 30% with five patients dying on the first day from blood loss and nine dying during subsequent days from head injury. This study has important implications for trauma service development. Successful clinical management of the severely injured pedestrian requires close co-operation between pre-hospital and hospital care providers. An integrated hospital trauma team response is mandatory to ensure appropriate management of what is often a shocked, hypoxic, head-injured patient.

Abbreviated Injury Scale↗
PubMed1993

Factors affecting outcome in the resuscitation of severely injured patients.

This is a retrospective, hospital based study of the resuscitative management of 40 consecutive, multitrauma patients (Injury Severity Score (ISS) > 25) admitted directly from an inner metropolitan environment over a one year period. The aim was to identify physiological, anatomical and time variables that correlated with an adverse outcome. Such information would facilitate the development of management protocols to improve future care. The clinical management of airways, breathing, circulation and head injury was reviewed in both the pre-hospital and Emergency Department (ED) phases of care. Eleven patients died during the resuscitative phase, 10 from blood loss and one from head injury. Nine patients died during the definitive care phase, seven from head injury and two from multiple organ failure. Scene hypotension (systolic blood pressure < or = 80 mmHg), ED Glasgow Coma Scale < 9, ISS > or = 50, and Revised Trauma Score < or = 4 were variables that correlated strongly with fatal outcomes. The median pre-hospital time was 33 min for those hypotensive in the field. The median ED time was 70 min for hypotensive patients who went to operating theatres. Survival following severe trauma may be increased by avoiding secondary insults in head injured patients and improving the management of haemorrhagic shock. The time frame from accident to operating theatre should be kept under 90 min. Warmed blood, fresh frozen plasma and platelets should be used early in the resuscitation. An early move to definitive control of bleeding should accompany vigorous volume resuscitation.

Blood Circulation↗
PubMed1993

Value of the prospective 'before and after' study as a methodology to evaluate outcome in a trauma centre.

A series of interventions (administrative, clinical and educational) was introduced to improve the quality of trauma care at Royal Prince Alfred Hospital, the designated trauma centre for the Central Sydney Area Health Service (CSAHS). A prospective, 'before and after' study was conducted to assess changes in outcome following the introduction of these measures. The trauma centre survival rate for patients admitted with serious injury (Injury Severity Scores > 15) increased significantly, from 72% in the nine months before trauma centre designation to 89% in the nine months after (P = 0.005). The peer review designated, potentially avoidable death rate did not change significantly over the two study periods, remaining in the 20-30% range. Similarly the unexpected death rate (TRISS) did not change significantly, remaining in the 20-45% range. A trend to a lower trauma centre mortality in those arriving with a systolic blood pressure < or = 90 mmHg was noted. Seven out of 14 patients 'at risk' from exsanguination died in the first 9 months compared with one out of seven in the second 9 months (P = 0.17). An unexpected finding was a change in the degree of injury severity and physiological status in patients arriving at the trauma centre. The Injury Severity Scores were significantly lower (P = 0.008) and the Revised Trauma Scores significantly higher (P = 0.0006) in the latter 9 months of the study. It was concluded that the improved trauma centre survival rate was a reflection of a reduced hospital mortality from haemorrhagic shock in conjunction with a lesser degree of injury severity in patients admitted from the CSAHS.

Adult↗
PubMed1992

Creeping angle-closure glaucoma. The influence of iridotomy and iridectomy.

In 16 patients (30 eyes) with creeping angle-closure glaucoma YAG laser iridotomy or surgical iridectomy was performed as part of treatment. The initial characteristics of the affected eyes (refractive state, intraocular pressure, anterior chamber depth, iris contour, gonioscopic features, extent and severity of synechia formation and result of dark-room testing in six eyes) are recorded, and also the influence on these features of iridotomy or iridectomy. Intraocular pressure was reduced on average by 2.46 mmHg (1.72 mmHg in non-trabeculectomised eyes) (P less than 0.02), and anterior chambers deepened on average by 0.05 mm (P less than 0.05). Extension of peripheral anterior synechiae was recorded in nine eyes.

Adult↗
PubMed1992

The effect of topical corticosteroids on laser-induced peripheral anterior synechiae.

PURPOSE: To assess the influence of different topical steroid agents and a non-corticosteroid medication after Argon laser trabeculoplasty (ALT) on the development of peripheral anterior synechiae (PAS) and the reduction of intraocular pressure (IOP). METHOD: In two separate prospective, randomised, group-controlled studies, topical fluorometholone 0.1% (FML Liquifilm) was compared with dexamethasone 0.1% (Maxidex) (Study A), or naphazoline hydrochloride 0.1% (Albalon) (Study B) after ALT for chronic open-angle glaucoma, with particular reference to the formation of PAS and the IOP response. RESULTS: In Study A (N = 109) eyes treated with Maxidex had a significantly higher incidence of PAS than those treated with FML - 45% compared with 22%, P < 0.05 (normal deviate test). In Study B (N = 75) the incidence of PAS was equal in eyes treated with FML or Albalon (23%). In the two studies combined (N = 184), the development of PAS was associated with a significantly lower mean response of IOP to ALT - 1.47 mmHg compared with 3.22 mmHg, 0.01 < P < 0.05 (Student t-test). CONCLUSION: The incidence of PAS after ALT is significantly higher with the post-laser use of Maxidex than with FML, and is the same for Albalon as for FML. The therapeutic benefit of ALT is significantly reduced if PAS develop.

Administration, Topical↗
PubMed1991

Ocular surface and lacrimal disturbances in chronic graft-versus-host disease: the role of conjunctival biopsy.

Forty-four patients (21 male, 23 female) were studied following bone marrow transplantation (BMT): 40 after allogeneic, one after syngeneic and three after autologous transplantation. Diffuse punctate conjunctival and corneal epitheliopathy was seen in 27 (61%), reduced or disordered tear film in 26 (59%), acquired lacrimal outflow obstruction in three (7%) and posterior subcapsular lens opacities in five (12%) patients. Conjunctival histology showed abnormal features, including those of graft-versus-host disease (GVHD) in 41 patients. Of these, 28 (64%) had clinical and laboratory features of GVHD and six patients with no systemic evidence of GVHD had conjunctival histology specific for GVHD. We conclude that after BMT, subclinical changes of GVHD are very common in the periocular tissues and may be universal in long-term survivors following allogeneic BMT. Some minor conjunctival changes are more likely to be due to the primary disease or the transplant conditioning regimen. Conjunctival biopsy is useful in demonstrating low-grade GVHD or GVHD confined to the ocular structures and may be diagnostic in some cases.

Adolescent↗