S A Croal

Queen's University Belfast, Béal Feirste, Northern Ireland, United Kingdom

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Publications (4)19.31 Total impact

  • M A McNally · W G Kernohan · S A Croal · R A Mollan ·
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    ABSTRACT: The diagnosis of deep vein thrombosis after total joint arthroplasty is difficult. The most widely used method of detection is physical examination and selective venography, which are unreliable and expensive even when symptoms and signs are prominent. This study employed computerized strain gauge plethysmography (CSGP) to select symptomatic patients for venography. The incidence of detection by CSGP was increased from 16% to 81.7%. Repeated CSGP also was investigated, but although specificity was further enhanced, it was at the expense of sensitivity. The negative predictive value of the CSGP screening was high and comparable to that of venography and indicates that CSGP is useful in the management of patients with symptoms suggestive of deep vein thrombosis. Computerized strain gauge plethysmography results emphasize the low specificity and poor feasibility of clinical examination and venography. Computerized strain gauge plethysmography is strongly advocated as a selection procedure for invasive venography in total joint arthroplasty patients.
    Clinical Orthopaedics and Related Research 11/1993; · 2.77 Impact Factor
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    ABSTRACT: Deep venous thrombosis is a widely recognized medical problem which results in significant morbidity and mortality. Venography is the current 'gold standard' diagnostic test for deep venous thrombosis; however it is costly, invasive and is unnecessarily performed in 50% of cases. This paper describes a self-contained, non-invasive system for automatic venous occlusion plethysmographic measurement and analysis. An examination of 274 symptomatic limbs was conducted using strain gauge plethysmography and a subsequent venographic examination was then performed. The plethysmographic results were then compared with venography so as to develop a means of discrimination for thrombotic and non-thrombotic limbs. Strain gauge plethysmography using the Belfast DVT Screener yielded a sensitivity of 100% and a sensitivity of 66.3% for proximal segment DVT. The efficacy of the discriminatory algorithm was then tested for the diagnosis of DVT in a further 101 symptomatic patients. A sensitivity of 94.7% and a specificity of 81.7% were observed for strain gauge plethysmography for proximal segment thrombosis in this patient group. The Belfast DVT Screener is highly sensitive for deep venous thrombosis and may be used to reduce the need for venography, which is of benefit to both the patient and clinician.
    Journal of Biomedical Engineering 04/1993; 15(2):135-9. DOI:10.1016/0141-5425(93)90043-X
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    ABSTRACT: We have developed a computer controlled system of strain gauge plethysmography for use as a screening tool for proximal segment venous thrombi which is simple to use, well tolerated by patients and extremely accurate. The computerised test was evaluated in 171 limbs of 163 symptomatic patients by comparison with subsequent ascending venography. Each of twenty occlusive proximal segment thrombi were identified, one non occlusive thrombus screened normal giving an overall sensitivity of 95.2%. The specificity of the test was 80% with a negative predictive value of 99.0%. The computerised system allows accurate screening for proximal segment venous thrombosis, and may permit more selective use of venography in the symptomatic post-operative limb.
    Thrombosis Research 06/1992; 66(2-3):207-14. DOI:10.1016/0049-3848(92)90190-L · 2.45 Impact Factor
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    M D Laverick · S A Croal · R.A.B. Mollan ·
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    ABSTRACT: To assess attitudes to the use of thromboprophylaxis among orthopaedic surgeons in the United Kingdom. Single page postal questionnaire to all 926 active orthopaedic surgeons who are members of the British Orthopaedic Association. The response rate was 70% (659 surgeons), of whom 595 (90%) used some form of prophylaxis. Most (548; 83%) used drugs but 47 (7%) used only elasticated stockings. A history of thromboembolic disease, hip surgery, and obesity was seen as the main risk factor. Ineffectiveness was the principal reason for not using prophylaxis. Most orthopaedic surgeons use regimens of thromboprophylaxis, though many of these are of limited value. Improvements in the efficacy and safety of prophylactic agents, combined with ease of administration, would increase the use of such agents and make orthopaedic surgery safer for the patient.
    BMJ Clinical Research 10/1991; 303(6802):549-50. DOI:10.1136/bmj.303.6802.549 · 14.09 Impact Factor