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Biomedical subjects

W G Murphy

Publications and source records attributed to W G Murphy.

At least 37 records · Page 2Linked to original sources
PubMed1995

Endothelial cell ultrastructure after aortic aneurysm rupture: an electron microscopy study.

Endothelial cell activation as an early response to hypovolaemic shock may be important in the pathogenesis of coagulopathy and multiple organ failure after aortic aneurysm rupture. The aim of this study was to determine whether any evidence could be found of changes in endothelial cell ultrastructure in patients undergoing operation for ruptured aneurysm and to establish a model for future studies of endothelial cells in these patients. At the start of operation, fat samples from the anterior abdominal wall were taken from five patients with ruptured abdominal aortic aneurysms and in an identical fashion from five control patients undergoing elective surgery. Endothelial cells lining capillaries were examined by transmission electron microscopy. Photomicrographs were taken of all capillaries present and these were assessed blindly by three independent observers. When compared with controls it was found that the luminal surface of the endothelial cells in patients with aneurysm rupture was more convoluted, with more frequent processes projecting into the lumen of the capillary. Budding of the luminal surface of the endothelial cell was seen in 11 of 45 capillaries in the rupture group and in none of 44 capillaries in the control group (P < 0.005). Budding was seen in at least one capillary of all five patients presenting with rupture but in none of the control group (P < 0.05). In conclusion, at the ultrastructural level there are changes within endothelial cells in capillaries at an early stage after ruptured abdominal aortic aneurysm.

Aortic Aneurysm, Abdominal↗
PubMed1995

Fibrin sealant reduces suture line bleeding during carotid endarterectomy: a randomised trial.

OBJECTIVES: To determine whether topical fibrin sealant reduced suture line bleeding during carotid endarterectomy with polytetrafluoroethylene (PTFE) patch closure. DESIGN: Prospective randomised non-blinded control trial. SETTING: Regional vascular surgery unit. MATERIALS: Seventeen patients undergoing carotid endarterectomy were randomised either to receive fibrin sealant as a topical haemostatic agent at the arteriotomy suture line or to act as control. OUTCOME MEASURES: Time taken to achieve haemostasis at the suture line. Intraoperative blood loss. Total operative time. RESULTS: The median time to achieve haemostasis was 5.5 min (range 4-31 min) in the treatment group and 19 min (range 10-47 min) in the control group. This difference was statistically significant p < 0.005 by Mann-Whitney test. There was no statistical difference in total operative time. Operative blood loss was lower in the treatment group (median 420ml, range 300-500ml) than in the control group (median 550ml, range 350-1200ml) but this difference was not statistically significant. One patient in the control group suffered a perioperative thrombo-embolic event. CONCLUSION: Fibrin sealant is an effective topical haemostatic agent for arteriotomy suture lines involving PTFE material.

Aged↗
PubMed1995

Rate of growth of Pseudomonas fluorescens in donated blood.

AIMS: To examine how delayed refrigeration of blood affects the growth of Pseudomonas fluorescens, one of the two most important causes of sepsis resulting from transfusion of contaminated blood. METHODS: Two donations of whole blood were each divided into three aliquots and inoculated with 5-10 cfu/ml of a P fluorescens strain from a case of transfusion associated sepsis. From each donation, one aliquot was placed at 4 degrees C, one was held at 20 degrees C for six hours prior to refrigeration and the third was held at 20 degrees C for 24 hours prior to refrigeration. Samples were aseptically withdrawn over 17 days and bacterial counts were determined using a pour plate technique. RESULTS: The rate of growth of P fluorescens in blood at 20 degrees C was increased compared with blood at 4 degrees C. At 24 hours the aliquots held at 20 degrees C for six and 24 hours had, respectively, 174 and 29,000 cfu/ml compared with 15 cfu/ml in aliquots held at 4 degrees C. There was no evidence of increased killing of P fluorescens at the higher temperature. CONCLUSIONS: These results suggest that blood for transfusion should be refrigerated as soon as possible after collection.

Blood↗
PubMed1995

Blood use for surgical patients: a study of Scottish hospital transfusion practices.

The use of an effective schedule for ordering blood for transfusion for surgical patients is the accepted standard of practice for hospital blood banks in UK hospitals. The use of maximum surgical blood ordering schedules (MSBOS) was surveyed throughout Scotland in 1992 and 1993. Twenty-seven hospitals participated in the study. Twenty-three (85%) of these 27 operated a schedule. Schedules varied between hospitals both in the way the schedules were implemented and in the amount of blood allocated to operations. The implementation of schedules was compared in three hospitals each for Caesarean section, transurethral resection of the prostate (TURP) and primary hip replacements. Adherence to the schedules averaged 76% (range 10-100%) and varied with operation, tariff, and hospitals. Blood use per operation did not depend on the amount of blood allowed by the schedule. Use of a MSBOS does not appear to influence clinical use of blood for transfusion, indicating that the gains in efficient use of laboratory resources and in safe handling of blood units can be made without compromising patient care.

Blood Banks↗
PubMed1995

Current blood transfusion practice in aortic aneurysm surgery in Scotland. The Scottish Vascular Audit Group.

A questionnaire on current practice in blood transfusion during aortic aneurysm repair was sent to all consultant surgeons with a vascular interest practising in Scotland. Replies were received from 31 surgeons. A blood ordering schedule was operated by 29 surgeons for elective operations and 26 surgeons for emergency operations. The mean number of units of red cell concentrate ordered was 4.7 units for elective operations (range 3-8 units) and 8 units for emergency operations (range 6-12 units). The time estimated to obtain red cell concentrate was 38.2 min (range 15-90 min) for a new request and 8.8 min (range 2-30 min) to obtain further blood in a patient already crossmatched. Blood conservation techniques employed included the use of low porosity or sealed grafts by 86% of surgeons. Autotransfusion was used by six surgeons, but only regularly by three surgeons. One surgeon used pre-deposit autologous transfusion and one used preoperative haemodilution. Intravenous heparin was used by 90% of surgeons during elective operations and by 16% of surgeons during emergency operations. Most surgeons used a standard dose of 5000 units of heparin.

Aortic Aneurysm↗
PubMed1994

Postoperative haemorrhage following aortic aneurysm repair.

Between 1988 and 1993, 17 (3%) out of a total 654 patients underwent reoperation for control of haemorrhage following repair of abdominal aortic aneurysm in a vascular surgery unit. The first operation was performed for rupture in 12 cases and electively in five. The incidence of reoperation for postoperative bleeding was 1.7% following elective operation and 3.3% following emergency operation. Case-controls, matched for sex and primary operation, were identified. The mortality rate in those requiring reoperation was 58% compared with 23% in the control group (p = 0.037). Seven patients suffered progressive deterioration and died in the early postoperative period. Of the remaining ten patients, four suffered unexpected serious complications; two a fatal cerebro-vascular accident (CVA), one a fatal myocardial infarction (MI) and the fourth a non-fatal CVA. The patients requiring reoperation had greater blood loss (p < 0.05), greater transfusion requirements and lower core temperatures (p < 0.05) at the end of their first operation than the control group. All except one of the patients who bled had evidence of coagulopathy and had lower platelet counts than the control group both before and after the first operation. At reoperation there were multiple minor bleeding points in 11 patients, no active bleeding points in two patients and a discrete bleeding point in four patients. In conclusion, re-operation for control of postoperative haemorrhage is an uncommon complication which is strongly associated with coagulopathy, may predispose to "rebound" postoperative thrombotic episodes, and carries a poor prognosis.

Aged↗
PubMed1994

Modeling the growth of Yersinia enterocolitica in donated blood.

BACKGROUND: Sepsis and death subsequent to the transfusion of blood containing Yersinia enterocolitica is an increasing problem. The organisms probably originate from bacteremia in the donor and can subsequently multiply at low temperature. STUDY DESIGN AND METHODS: Reported here are experiments with a strain of Y. enterocolitica associated with a case of transfusion-associated bacteremia. RESULTS: It was found that the rapid early killing of Y. enterocolitica injected into donated blood does not require viable phagocytes and can be explained by complement-mediated killing. Complement resistance in Y. enterocolitica is known to be plasmid-coded. It is expressed at 37 degrees C, but not at 20 degrees C, and is favored by calcium-deficient culture media. Y. enterocolitica organisms induced to express complement resistance were still killed in donated blood, though the initial rate was slower. Such organisms multiplied in plasma at 37 degrees C, but were killed after 6 hours of incubation at 20 degrees C, presumably because complement resistance genes are switched off at this temperature. CONCLUSION: This experiment is thought to reflect the natural history of Y. enterocolitica contamination of blood, in which complement-resistant organisms in the donor blood encounter lower temperatures after donation. These observations suggest that the practice of plasma depletion may have contributed to the increased incidence of mortality due to Y. enterocolitica contamination of donated blood.

Blood↗
PubMed1994

Use of aprotinin in knee replacement surgery.

We have studied the effect of aprotinin on blood loss and subsequent blood transfusion in 17 patients undergoing knee replacement surgery. Patients receiving aprotinin (total dose 2,000,000 kallikrein inhibiting units) received fewer units of blood than control patients (P < 0.05), although there was no significant difference in blood loss between the two groups. The study was stopped when one patient in the aprotinin group needed an above-knee amputation because of ischaemia secondary to arteriovenous thrombosis after knee replacement surgery. Although the patient had peripheral vascular disease which could have accounted for the thrombosis, the role of aprotinin under tourniquet conditions is unclear.

Aged↗
PubMed1994

Causes and clinical consequences of Rhesus (D) haemolytic disease of the newborn: a study of a Scottish population, 1985-1990.

OBJECTIVE: To identify the reasons behind failures to prevent the development of Rhesus (D) haemolytic disease of the newborn. DESIGN: Retrospective analysis of the case records of all pregnancies that resulted in the birth of an infant with a positive direct antiglobulin test on the cord red cells born to Rh(D) negative women between 1 April 1985 and 31 March 1990. SETTING: Obstetric units in the South East Scotland region and the South East Scotland Regional Blood Transfusion Service Antenatal Laboratory. MAIN OUTCOME MEASURES: The causes and clinical consequences of maternal immunisation to the Rhesus (D) antigen. RESULTS: Between 1985 and 1990, 80 pregnancies resulted in the birth of an infant sensitised with anti-D on the cord red cells. There were no deaths due to haemolytic disease, but considerable resources were deployed in obstetric and neonatal care for these pregnancies. Sufficient data were available to categorise the cause of maternal immunisation in 70 pregnancies. Seven cases were due to immunisation by pregnancy before 1970. Sixty-three cases could be attributed to failure of the Rhesus programme: 10 cases (16%) were due to failure to implement the programme adequately, the other 53 cases (84%) were due to failure of the current guidelines to provide adequate protection. Late immunisation in an uncomplicated pregnancy was the single commonest identifiable cause. CONCLUSIONS: It is likely that substantial further reductions in Rhesus (D) immunisation and haemolytic disease of the newborn will require changes in the Rhesus prevention programme. In particular the role of antenatal prophylaxis requires detailed consideration.

Erythroblastosis, Fetal↗
PubMed1994

Implementation of the rhesus prevention programme: a prospective study.

All rhesus-negative women who completed a pregnancy between January and August 1992 in two Scottish regions were studied to assess whether the administration of the rhesus prevention programme was complete: 671 rhesus positive (or rhesus type unknown) pregnancies were completed in 1120 Rh D negative women. For eight pregnancies no record of Rh D administration at birth was available. For recorded antenatal events that should have resulted in its administration anti-D was given in 195/280 (69.6%). Kleihauer testing was carried out in 9 of 98 instances of antepartum haemorrhage occurring after 20 weeks gestation. No cases of antenatal immunisation were identified. The study identified a need to increase awareness of the necessity for anti-D administration after potentially immunising events during pregnancy, and for increasing compliance with administration of postnatal anti-D in one of the study regions. Re-evaluation is also required of the recommendation that Kleihauer testing should be done when antenatal anti-D is given following an obstetric event after 20 weeks.

Female↗
PubMed1993

Preoperative coagulopathy in ruptured abdominal aortic aneurysm predicts poor outcome.

In a prospective study of 50 consecutive patients undergoing operation for ruptured abdominal aortic aneurysm, a coagulation screen was performed on admission to hospital. Twenty patients with either a platelet count < 100 x 10(9)/l or a prothrombin time > 1.5 times the control value had a mortality rate of 65 per cent (95 per cent confidence interval 45-85 per cent); a further 23 patients with normal screen results had a mortality rate of 9 per cent (95 per cent confidence interval 0-20 per cent) (P < 0.001). Seven patients, of whom three died, did not have an admission coagulation screen performed. Patient age in the study group did not have independent statistical predictive power. This study indicates that coagulopathy at the time of admission predicts poor outcome in patients with ruptured aortic aneurysm. Current management strategies are inadequate for the treatment of these patients, who can be rapidly identified on admission by means of platelet and prothrombin counts.

Aortic Aneurysm, Abdominal↗