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Biomedical subjects

A N McLean

Publications and source records attributed to A N McLean.

14 recordsLinked to original sources
PubMed2006

Blunt cervical spine trauma as a cause of spinal cord injury and delayed cortical blindness.

STUDY DESIGN: Case report. OBJECTIVE: To present and discuss the case of a patient who sustained a significant flexion compression injury of the cervical spine with resulting tetraplegia and development of cortical blindness. SETTING: National Spinal Injuries Unit and Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, UK. METHODS: Clinical and radiological follow-up of the patient. RESULTS: Cortical blindness resulted from vertebral artery dissection associated with blunt cervical spine trauma. The patient is registered blind and is ventilator dependent. CONCLUSION: The potential complications of blunt vertebral artery injury remain poorly recognised. Screening is routinely not performed. Advances in noninvasive radiological techniques may result in recognition of asymptomatic disease and the potential for therapeutic intervention.

Adult↗
PubMed2006

A control system for automatic electrical stimulation of abdominal muscles to assist respiratory function in tetraplegia.

People with tetraplegia have poor respiratory function leading to limited tidal volume (V(T)) and reduced cough peak flow (CPF). These problems may cause respiratory failure during the initial admission or subsequent intercurrent illness. Electrical stimulation of the abdominal muscles during expiration can improve respiratory function by increasing V(T) and CPF. We developed a novel control system to automatically trigger muscle stimulation, synchronised with the subject's voluntary respiratory activity. The system was tested in four subjects with a functionally complete lesion at level C4 to C6, aged between 16 and 46 years, 3 months to 5 years post injury, who were breathing spontaneously. The algorithm delivered automatic stimulation patterns, detecting cough and quiet breathing while suppressing stimulation during other activities such as speaking. Marked increases in V(T) (between 9% and 71% of baseline) and CPF (between 31% and 54% of baseline) were observed, suggesting that the technique may have potential use in both acute and established tetraplegia to increase minute ventilation and to improve cough clearance of secretions.

Abdominal Muscles↗
PubMed2005

Comparison of stimulation patterns for FES-cycling using measures of oxygen cost and stimulation cost.

AIM: The energy efficiency of FES-cycling in spinal cord injured subjects is very much lower than that of normal cycling, and efficiency is dependent upon the parameters of muscle stimulation. We investigated measures which can be used to evaluate the effect on cycling performance of changes in stimulation parameters, and which might therefore be used to optimise them. We aimed to determine whether oxygen cost and stimulation cost measurements are sensitive enough to allow discrimination between the efficacy of different activation ranges for stimulation of each muscle group during constant-power cycling. METHODS: We employed a custom FES-cycling ergometer system, with accurate control of cadence and stimulated exercise workrate. Two sets of muscle activation angles ("stimulation patterns"), denoted "P1" and "P2", were applied repeatedly (eight times each) during constant-power cycling, in a repeated measures design with a single paraplegic subject. Pulmonary oxygen uptake was measured in real time and used to determine the oxygen cost of the exercise. A new measure of stimulation cost of the exercise is proposed, which represents the total rate of stimulation charge applied to the stimulated muscle groups during cycling. A number of energy-efficiency measures were also estimated. RESULTS: Average oxygen cost and stimulation cost of P1 were found to be significantly lower than those for P2 (paired t-test, p<0.05): oxygen costs were 0.56+/-0.03l min-1 and 0.61+/-0.04l min-1 (mean+/-S.D.), respectively; stimulation costs were 74.91+/-12.15 mC min-1 and 100.30+/-14.78 mC min-1 (mean+/-S.D.), respectively. Correspondingly, all efficiency estimates for P1 were greater than those for P2. CONCLUSION: Oxygen cost and stimulation cost measures both allow discrimination between the efficacy of different muscle activation patterns during constant-power FES-cycling. However, stimulation cost is more easily determined in real time, and responds more rapidly and with greatly improved signal-to-noise properties than the ventilatory oxygen uptake measurements required for estimation of oxygen cost. These measures may find utility in the adjustment of stimulation patterns for achievement of optimal cycling performance.

Biomedical Engineering↗
PubMed2005

Delayed hydrocephalus as an unusual complication of a stab injury to the spine.

STUDY DESIGN: Case report. OBJECTIVE: To report a rare complication following a stab injury to the upper cervical spine and cord. SETTING: National spinal injury unit in a Scottish university teaching hospital. CASE REPORT: A 19-year-old male sustained a stab injury to his upper cervical spine, with a partial cord transection. After 5 months of rehabilitation, his condition deteriorated. CT scans showed hydrocephalus, which was treated by shunting. After shunting, the patient's condition improved but he remained tetraplegic requiring ventilatory support at night. CONCLUSION: Hydrocephalus as a late complication of a cervical spine injury is rare but should be considered if the condition of the patient with an upper cervical spine injury deteriorates. The likely mechanism of the hydrocephalus development is also discussed.

Adult↗
PubMed2004

Spinal cord infarction due to a self-inflicted needle stick injury.

STUDY DESIGN: Case report. OBJECTIVE: To report a case of spinal cord infarction after a self-inflicted needle stick injury, following an injection of heroin into the cord. SETTING: National spinal injury unit in a Scottish University teaching hospital, Glasgow, UK. CASE REPORT: A 20-year-old male, injected street heroin accidentally into the cord through the left side of the neck, leading to sudden loss of power to all four limbs. Initial magnetic resonance imaging scans showed extensive cord oedema and follow-up scans showed signal changes within the anterior horns of the spinal cord in keeping with a cord infarct. CONCLUSION: Self-inflicted spinal cord injury with a small needle is difficult, but not impossible. Cord infarct as a result of a self-inflicted injury has not been previously reported. The mechanism of the injury resulting in cord infarction is explained by the vascular anatomy of the spinal cord circulation, and this may also explain the residual neurological status of the patient.

Adult↗
PubMed2003

Rupture of tuberculous spinal abscess resulting in tuberculous empyema and chylothorax.

STUDY DESIGN: Case report with a review of scientific literature. OBJECTIVE: To describe the course of tuberculous spinal disease (Pott's disease) complicated by pyogenic and tuberculous empyema, and chylothorax as there has been an increase in the numbers of notified cases of tuberculosis in the UK(1). To the best of our knowledge, a similar case has not been reported previously in the UK, although there has been a report of bilateral chylothorax associated with Pott's disease. SETTING: A national spinal injuries unit in a Scottish university teaching hospital. METHODS: Review of literature on the chemotherapy of spinal tuberculosis and the role of streptokinase in the treatment of empyema and the relation between spinal tuberculosis, empyema and chylothorax. RESULTS: Although spinal tuberculosis was recognised and treated appropriately with chemotherapy, the patient sustained pleural involvement with later development of both empyema and chylothorax. CONCLUSION: The case highlights the difficulties in the treatment of tuberculosis of the spine inspite of the presence of fully sensitive organisms and early institution of appropriate chemotherapy. In the absence of surgical debridement, the duration and dosage of chemotherapy as practised in the initial period may have to be prolonged into the continuation phase. The thoracic duct can be damaged either because of extension of the tuberculosis itself or because of instillation of intrapleural streptokinase for treatment of pleural empyema leading to chylothorax. There is a need for randomised trials of intrapleural streptokinase treatment in tuberculous empyema.

Aged↗
PubMed2002

Delayed presentation of post-traumatic aneurysm of the posterior inferior cerebellar artery in a patient with spinal cord injury.

STUDY DESIGN: A case report. OBJECTIVE: To present and discuss the case of a patient with serious head and spinal injuries who suffered delayed haemorrhage from a post-traumatic aneurysm of the right posterior inferior cerebellar artery following surgical treatment of vertebral fracture and hydrocephalus. SETTING: National Spinal Injuries Unit and Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, UK. METHODS: Clinical and radiological follow-up of the patient. RESULTS: The aneurysm was treated by coil occlusion of the right vertebral artery. Post-operative films showed that the aneurysm had been successfully obliterated. CONCLUSION: Post-traumatic cerebral aneurysms are very rare. Neurosurgical and rehabilitation teams need to be aware of this late treatable sequela of head injury.

Adolescent↗
PubMed2001

Prophylaxis of thromboembolism in spinal injuries--results of enoxaparin used in 276 patients.

OBJECTIVE: To evaluate the results of thromboembolic prophylaxis using enoxaparin in acute spinal injury patients. BACKGROUND: Deep vein thrombosis and pulmonary embolism are major causes of morbidity and mortality in patients with acute spinal injuries. A wide range of thromboprophylactic measures have been proposed. The present study describes the outcome of a regime of enoxaparin and antithromboembolic stockings in acute spinal injuries irrespective of neurological damage. SETTING: Scotland, UK. METHODS: Eighteen-month retrospective review of acute spinal injury patients admitted to a national spinal injuries unit. A thromboembolic prophylactic regimen of early mobilisation, use of antithromboembolic stockings, and subcutaneous administration of enoxaparin 40 mg once a day until patients could be mobilised for more than 4 h per day, was used. Patients with clinical suspicion of deep venous thrombosis or pulmonary embolism were investigated as appropriate. RESULTS: Out of 146 (53% of total) patients with spinal injuries with no neurological deficit only one patient (0.4%) developed clinical evidence of pulmonary embolism and out of 130 (47% of total) with spinal cord injury two (0.7%) developed clinical evidence of deep venous thrombosis while still on enoxaparin. Four patients (1.5%) developed deep venous thrombosis and one (0.4%) pulmonary embolism after discontinuing enoxaparin. There were no fatal pulmonary emboli and one suspected intraspinal bleeding. CONCLUSIONS: The present study suggests that, in addition to physical and mechanical measures, low molecular weight heparin in the form of enoxaparin 40 mg administered once daily compares favourably with previous studies for thromboprophylaxis in acute spinal injuries.

Acute Disease↗
PubMed2000

Scottish national bronchoscopy audit: a prospective multicentre study of 3316 cases against agreed standards. Scottish Thoracic Society.

INTRODUCTION: Bronchoscopy guidelines address issues of patient and operator safety but do not give guidance on the expected yield of the procedure. Realistic standards for several outcome measures of bronchoscopy for investigating bronchial carcinoma have been derived by Scottish clinicians from a published national study. The present study describes the use of these agreed standards in prospective audit. METHODS: All Society members in Scotland (population 5.1 million) were invited to participate. Data were collected for 1 year and coded anonymously. STANDARDS: 1. Supervising bronchoscopist to have completed at least 100 procedures; 2. histology to be positive in 80% of cases where tumour seen; 3. 35%-55% of bronchoscopies to reveal a diagnosis; 4. 60% of patients admitted for bronchoscopy to be day cases; 5. 80% of day case patients to be in hospital for less than 6 h; 6. 90% of male patients and 80% of female patients willing to have repeat bronchoscopy. RESULTS: Three thousand, three hundred and sixteen bronchoscopies were performed by 45 senior pulmonologists at 22 centres. One centre reached all the standards and five centres met five standards. There was wide national variation in histological spectrum, incidence of small cell cancer ranged from 12% to 25% between centres. Participants found their own data helpful in identifying local areas for improvement. CONCLUSION: Bronchcoscopy standards set locally by practising pulmonologists can be used in collaborative audit to identify areas for improving practice. Variation in histology may be accounted for by case-mix or pathology techniques.

Bronchoscopy↗
PubMed1998

The Scottish multi-centre prospective study of bronchoscopy for bronchial carcinoma and suggested audit standards.

Fibre-optic bronchoscopy is widely used to diagnose bronchial carcinoma. There is considerable variation in techniques for patient sedation, methods of obtaining samples and histopathological yield. We wished to examine variations in practice in different centres throughout Scotland and derive realistic audit standards for best clinical practice from these results. Diagnostic bronchoscopies from five centres were included. Patient details, grade of individual performing the test, endobronchial abnormalities, specimens taken and the histocytological yield were recorded. A patient satisfaction questionnaire was completed. One thousand eight hundred and two bronchoscopies were performed to look for bronchial carcinoma. Sedation and anaesthesia techniques varied considerably between centres. There were marked differences in patient satisfaction between centres. Nearly twice as many females as males would prefer not to have bronchoscopy repeated. Six hundred and fifty-eight carcinomas were confirmed by histocytology. Yield was unaffected by the grade of doctor performing bronchoscopy. Improving yield may be achieved by increasing the number of sampling techniques employed and changing the order in which specimens are taken (biopsies first and washings last). Eighty-seven percent of endoscopically visible tumours were confirmed histocytologically. There was a considerable variation in histological spectra between centres that may relate to differences in pathological interpretation rather than actual differences in case mix. Suggested audit standards are discussed. This study demonstrates the variety of techniques and also the levels of histocytological yield and patient satisfaction that can be achieved. Provisional standards of practice for this procedure have been agreed with a view to auditing performance against these. It is hoped that centres will adopt the methods that are shown to achieve the highest standards.

Ambulatory Care↗
PubMed1998

Investigation of pleural effusion: an evaluation of the new Olympus LTF semiflexible thoracofiberscope and comparison with Abram's needle biopsy.

STUDY OBJECTIVES: Recently, pulmonologists have performed thoracoscopy under local anesthesia using rigid thoracoscopes or flexible bronchoscopes. The latter allow greater access within the pleural cavity but are difficult to manipulate. The Olympus LTF semiflexible fiberoptic thoracoscope combines features of both instruments, having a solid body and a flexible terminal section. In the first study with this instrument, we evaluated ease of use and compared diagnostic yield with closed needle biopsy. PATIENTS: Twenty-four patients with pleural effusion were investigated. SETTING: Scottish University Hospital. DESIGN: Thoracoscopy was performed in the bronchoscopy suite after premedication with atropine and papaveretum. Following a standard Abram's needle biopsy, the LTF thoracoscope was inserted through a flexible introducer (Olympus Optical Co Ltd; Tokyo, Japan). The pleura was inspected and biopsy specimens were taken of suspicious areas. RESULTS: The final diagnosis was malignant pleural effusion in 16 of 24 patients. Ten of 16 were positive by Abram's biopsy, giving a sensitivity of 62%. Thirteen of 16 were positive by fiberoptic thoracoscopy, giving an improved sensitivity of 81%. The LTF thoracoscope was easy to use for pulmonologists experienced in rigid thoracoscopy and flexible bronchoscopy. Excellent views of the pleura were obtained from a single entry point. The procedure was well tolerated and no complications were encountered. CONCLUSION: The LTF thoracoscope allows excellent pleural access but a larger biopsy channel (currently 2 mm) might increase the accuracy of diagnosis.

Adjuvants, Anesthesia↗
PubMed1997

Sports supplement drinks and dental health in competitive swimmers and cyclists.

AIM: To assess dental status and sports supplement uptake in swimmers and cyclists. To determine chemico-physical properties of the most popular sports drinks. DESIGN: Descriptive, prevalence study of tooth wear and caries experience. Questionnaire analysis of sports drinks usage. SETTING: Two public swimming pools in Liverpool and three cycle clubs in North West England. SUBJECTS AND METHOD: A convenience sample of swimmers and cyclists was examined for caries and tooth wear. A questionnaire ascertained which sports drinks were consumed and their pattern of consumption. pH and titratable acidity, concentrations of calcium, phosphate and fluoride, and viscosity were analysed. Salivary flow rate in response to these drinks and water was also determined. RESULTS: 25 swimmers and 20 cyclists participated. Caries experience and tooth wear into dentine (excluding incisally exposed dentine) was significantly more frequent among cyclists (P < 0.05). Cyclists had significantly more upper palatal wear (P < 0.001). Pattern of sport drink consumption between the two groups was significantly different (P < 0.001). pH range of the most popular sport drinks was 2.4-4.5. Salivary flow rate after a 1-minute rinse was significantly lower (P < 0.05) with one drink (0.47 ml/min) and water (0.41 ml/min) compared with the other drinks. CONCLUSIONS: An association between caries or erosive tooth wear and sport drink consumption was not found. However, the erosive potential of sport drinks is real and must be borne in mind as an aetiological factor for erosion in young people.

Adolescent↗
PubMed1997

Clinical features and epidemiology of malignant pleural mesothelioma in west Glasgow 1987-1992.

Malignant pleural mesothelioma is almost exclusively caused by exposure to asbestos dust. Recent epidemiological studies have suggested that the national incidence of disease may continue to rise until 2020 and that asbestos exposure in the building trade may be replacing shipyard related exposure as the main source of disease. The objective of the study was to determine if the incidence of malignant pleural mesothelioma was rising in the west of Glasgow from 1987-1992 and whether there had been a change in clinical features compared to previous studies from the same population. Case notes identified from coded returns and the local cancer registry were retrospectively examined: 144 cases were identified. This is an increase in incidence of over 50% compared to the previous study but the yearly incidence did not rise over the period studied. The clinical features and survival times have not changed since previous studies: median survival remains 30 weeks. Only three patients were given definitive treatment reflecting the lack of effective therapy. We suggest that the incidence of mesothelioma in the population studied may already have peaked resulting from the decline in the local shipyard industry over 20 years ago. Non-shipyard sources of asbestos exposure may be less important in this area.

Adult↗