PubMed Health⌕ Search

Biomedical subjects

P Armstrong

Publications and source records attributed to P Armstrong.

At least 19 recordsLinked to original sources
PubMed1992

Magnetic resonance imaging of anal fistulae.

Success of surgery for an anal fistula depends on accurate assessment of the fistula; however, such assessment is technically difficult. We have done a prospective study that determined the accuracy of magnetic resonance imaging (MRI) in demonstrating the course of fistulae, by comparing MRI scan interpretations with subsequent operative findings. 16 patients (mean [range] age 42 [24-66] years) had MRI followed by surgery within a mean of 22 (1-101) days. MRI scan interpretations agreed precisely with independently documented operative findings in 14 of 16 patients. MRI is an accurate method of delineating anal fistulae, and should be considered for patients with difficult fistulae that recur despite skilled attention because it demonstrates abnormalities that might otherwise be missed.

Adult↗
PubMed1992

Confronting the issues of patient safety and investigator conflict of interest in an international clinical trial of myocardial reperfusion. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) Steering Committee.

The Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO) trial is a large scale international trial of new myocardial reperfusion strategies. The primary hypothesis is that early and sustained coronary artery recanalization will be associated with a significant reduction in mortality. The four regimens that are being tested are 1) streptokinase with subcutaneous heparin; 2) streptokinase with intravenous heparin; 3) accelerated recombinant tissue-type plasminogen activator (rt-PA) with intravenous heparin; and 4) combination streptokinase, rt-PA and intravenous heparin. The planned recruitment of 41,600 patients in 1,500 sites from 15 countries is expected to be completed by December 1992 and will enable detection of a 15% reduction or 1% absolute difference in mortality compared with that associated with standard therapy (streptokinase and subcutaneous heparin). In designing the trial, two important issues were directly addressed. First, a strategy was developed to provide assurance of patient safety during large scale investigational use of an aggressive thrombolytic regimen. This includes fascimile transmission of a one-page safety summary form to the Data Coordinating Center within 24 h of death or discharge, acceptance of the concept of "net clinical benefit" and close surveillance of the trial's progress by the independent Data and Safety Monitoring Committee. Second, to avoid potential conflict of interest beyond elimination of any position of financial equity, the Steering Committee unanimously voted to prohibit any honoraria for speaking engagements, payment for consultancy or travel or reimbursement of any kind from any of the five corporate sponsors until 1 year after publication of the results. Incorporation of these approaches may facilitate the design of future large scale randomized trials in cardiovascular medicine.

Biomedical Research↗
PubMed1992

Proton NMR relaxation times in the normal human liver at 0.08 T.

The spin-lattice (T1) and spin-spin (T2) relaxation times of liver in 42 normal volunteers (21 male and 21 female) were measured using a calibrated 0.08 T resistive imager capable of accurate and reproducible relaxometry. T1 was determined using an interleaved gradient echo saturation recovery and inversion recovery technique and T2 using a four-echo Carr-Purcell-Meiboom-Gill sequence. The ranges obtained were T1 = 213 +/- 14 ms and T2 = 66 +/- 5 ms. More specific ranges were obtained for each sex and for younger and older subjects. A small variation in T1 was found between older (greater than 40 years) and younger (less than 40 years) subjects, but no such effect was observed in the case of T2. No significant variations were found when female volunteers were imaged at weekly intervals through the menstrual cycle, when a male volunteer was imaged repeatedly over the course of several months or when male volunteers consumed small quantities of alcohol.

Adult↗
PubMed1992

Case report: primary lymphoma of bone--MRI appearances with pathological correlation.

A case of primary lymphoma of bone involving the proximal tibia is presented. The magnetic resonance (MR) appearances were unusual for a primary malignant tumour, with predominantly low signal intensity on both T1- and T2-weighted images. This correlated with marked fibrosis on histology. These observations are discussed in the context of previous reports of MRI in bone lymphoma.

Adult↗
PubMed1992

Surgical face masks are effective in reducing bacterial contamination caused by dispersal from the upper airway.

We have studied the effectiveness of surgical face masks in reducing bacterial contamination of a surface, produced by dispersal of organisms from the upper airway. Twenty-five volunteers were asked to speak at blood agar plates positioned in close proximity to the mouth, initially whilst not wearing a face mask and then wearing a surgical face mask over the mouth and nose. A fresh face mask almost completely abolished bacterial contamination of agar plates 30 cm from the mouth. After 15 min there was an increase in the level of contamination which was statistically insignificant.

Adult↗
PubMed1992

Perceptions of psychological problems in general practice: a comparison of general practitioners and psychiatrists.

All general practitioners and psychiatrists working in a single health district were sent a questionnaire on their perceptions of the prevalence of psychological problems among patients consulting in general practice. One hundred and twenty-one GPs (75%) and 10 (83%) psychiatrists responded. GPs and psychiatrists agreed that up to 20% of consulting patients were likely to be clinically depressed; they also agreed on the most appropriate management, although GPs tended to be more conservative than psychiatrists would advise on making use of hospital services. GPs, however, believed non-specific psychological problems to be significantly less common than did psychiatrists. This expectation may help explain the reported failure of GPs to diagnose all psychological problems identified by formal psychiatric instruments.

Adult↗
PubMed1992

Thoracic epidural anaesthesia and primary pulmonary hypertension.

Patients with primary pulmonary hypertension occasionally present for surgery. Anaesthesia requires continuous cardiovascular monitoring and maintenance of stable pulmonary and systemic haemodynamics. The management of a patient with severe pulmonary hypertension, undergoing open lung biopsy under a combination of general anaesthesia and thoracic epidural analgesia is reported and the problems of primary pulmonary hypertension are discussed.

Adult↗
PubMed1992

Inappropriate reattendances in out-patient departments.

In an attempt to identify the number and characteristics of inappropriate reattendances at out-patient clinics, clinic doctors and patients in two specialties throughout a health district were given a questionnaire to complete on every patient attendance over one week. Four hundred and fifty-two patients were seen, and 293 were asked to reattend: in some 80 of the latter cases the clinic doctor felt that the GP could nevertheless manage the problem. These 'inappropriate' invitations to reattend were more likely to be given by junior hospital staff to long-standing patients of the clinic attending for monitoring purposes. The patients involved in these 'inappropriate' requests to reattend also tended to think that their GP could manage the problem. It is concluded that discharge policy needs to be made more explicit and training for juniors organized if out-patient resources are to be used most efficiently.

Health Services Misuse↗
PubMed1992

Radiology of lung cancer.

Papers in the review period have investigated the reasons why radiologists frequently overlook early lung cancers and have demonstrated that the rate at which radiologists falsely categorize a solitary pulmonary nodule as benign, through the use of commercially available CT phantom densitometry is higher than was previously believed. Attempts have also been made to find CT characteristics other than density that may help to distinguish benign from malignant nodules. A number of articles have addressed methods of improving the yield and reducing the pneumothorax rate following needle biopsy of pulmonary nodules. The major role of the radiologist when evaluating patients with known or probable lung cancer is to stage the tumor. The recent literature describing the accuracy of CT and MR imaging in staging lung cancer is also reviewed.

Biopsy, Needle↗
PubMed1992

Treatment of congenital pseudoarthrosis of the tibia using the Ilizarov technique.

The principle of treatment of congenital pseudoarthrosis of the tibia (CPT) with the Ilizarov method corrects all angular deformity and maximizes the cross-sectional area of union of the pseudoarthrosis. Fifteen patients with a total of 16 CPT were treated using the Ilizarov apparatus. Various forces were used to treat the pseudoarthrosis site including compression, distraction, open reduction, resection and shortening, resection and bone transport, and invagination of one end in the other. Lengthening was performed in 12 of the 16. Deformity was corrected in all cases. The union rate was 94% with one treatment and 100% with two treatments. There were five refractures, three early and two late. Previous pin sites, residual angular deformity, and natural history were considered predisposing factors for refractures. One patient refractured twice but remained ununited. Fifteen remained united, with a mean follow-up period of four years (range, two to seven). There were two residual deformities, one in the regenerate and one at the level of the CPT.

Adolescent↗
PubMed1991

Doctors' perceptions of pressure from patients for referral.

OBJECTIVE: To assess the effect of pressure from patients on patterns of general practitioners' outpatient referrals. DESIGN: Survey of general practitioners' referrals to hospital outpatient departments during one week. SETTING: One health district. SUBJECTS: All (160) general practitioners in the health district. MAIN OUTCOME MEASURES: Specialty of the referral, the reason for it, and its status (NHS or private) and the general practitioner's assessment of the degree of pressure exerted by the patient for the referral (much, little, or none). RESULTS: 122 (76%) general practitioners completed the survey. Younger general practitioners (aged less than or equal to 45) and those qualifying in the United Kingdom and Republic of Ireland reported greater pressure from patients to refer (p less than 0.03, p less than 0.001 respectively). Pressure was also greater for patients referred privately (p less than 0.001), for those referred for reassurance (p less than 0.05), and for those referred to clinics in psychiatry, rheumatology, dermatology, and orthopaedics. General practitioners with a higher referral rate (with total consultations in the week as the denominator) were more likely to report pressure (p less than 0.01). CONCLUSIONS: The pressure from patients to refer reported by general practitioners is related both to general practitioners' characteristics and to the nature of the referral. Pressure to refer seems to explain some of the variation in referral rates among general practitioners.

Adult↗
PubMed1991

Report of the Canadian Cardiovascular Society's consensus conference on the Management of the Postmyocardial Infarction Patient.

In October 1989, the Canadian Cardiovascular Society announced a program to achieve consensus on important issues in the care of patients with cardiovascular disease. This report on the management of the postmyocardial infarction patient represents the first in a series of these consensus conferences. The process for establishing consensus recommendations involved several steps. A primary panel of 11 experts from various fields was selected to review the available clinical evidence and to make a list of recommendations about management decisions in the postmyocardial infarction period. The initial report was distributed to a secondary panel of 16 reviewers* representing allied health care constituencies from across Canada. On the basis of the critical reviews and feedback from these reviewers, a revised report was distributed to all members (over 800) of the Canadian Cardiovascular Society for further review and feedback. This iterative approach resulted in a penultimate report that was presented at a plenary session of the annual scientific meeting of the Canadian Cardiovascular Society on Oct. 18, 1990, in Halifax, NS. On the basis of discussion and feedback from this symposium, the consensus review was completed.

Canada↗
PubMed1991

Nitrous oxide and formiminoglutamic acid: excretion in surgical patients and anaesthetists.

We have investigated the possible toxicity of nitrous oxide on vitamin B12 and its sequelae upon folic acid metabolism using the urine formiminoglutamic acid excretion test, an index of the functional state of folate metabolism. Ten control subjects not exposed to nitrous oxide and five patients receiving limb surgery under local anaesthesia excreted normal amounts of formiminoglutamic acid in urine for 6 days. Fifty patients received nitrous oxide anaesthesia for similar surgery and, of these, 22 had a dose-dependent increase in excretion on the first 2 days after operation. There were large individual variations. Exposure to 70% nitrous oxide appeared to cause abnormal metabolism of folate when exposure was greater than 90 min. Ten anaesthetists demonstrated normal excretion of formiminoglutamic acid; their exposure to nitrous oxide was typical of that in other studies of theatre environmental pollution.

Adult↗
PubMed1991

Addition of fentanyl to prilocaine for intravenous regional anaesthesia.

Fifteen volunteers underwent intravenous regional anaesthesia on two occasions using 40 ml 0.5% prilocaine, to which had been added either 2 ml 0.9% saline or 0.1 mg fentanyl (resultant concentration 2.5 micrograms/ml). There was no difference in the rate of onset of blockade of cold sensation from an ethyl chloride spray, or to sharp and touch pinprick sensation in either group. There was an increase in the incidence of nausea after tourniquet release in the fentanyl group. It is concluded that the addition of fentanyl 2.5 micrograms/ml to prilocaine 0.5% confers no benefit in intravenous regional anaesthesia.

Adult↗