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Biomedical subjects

C E Clark

Publications and source records attributed to C E Clark.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence and clinical implications of the inter-arm blood pressure difference: A systematic review.

A blood pressure (BP) difference between arms was first reported over 100 years ago. Knowledge of its prevalence and relevance to the accurate measurement of BP remains poor. Current hypertension guidelines do not emphasise it. The objectives of this study were to establish the best estimate of prevalence of the inter-arm difference (IAD) in the population, to consider its implications for accurate BP measurement and treatment, and to discuss its aetiology and potential as a risk marker for cardiovascular disease. Systematic literature review was carried out. The data sources were Medline EMBASE and CINAHL databases, and Index of Theses. Studies reporting prevalence rates of IAD were retrieved and considered for inclusion against explicit methodological criteria. Point prevalence rates were extracted and weighted mean prevalence rates calculated. The main outcome measures were weighted mean prevalences of systolic IAD > or =10 and > or =20 mm Hg and of diastolic IAD > or =10 mm Hg. Thirty-one studies were identified. Most had methodological weaknesses; only four met the inclusion criteria. Pooled prevalences of the IAD from these four studies were 19.6% systolic > or =10 mm Hg (95% CI 18.0-21.3%), 4.2% systolic > or =20 mm Hg (95% CI 3.4-5.1%) and 8.1% diastolic > or =10 mm Hg (95%CI 6.9-9.2%). In conclusion, an IAD is present in a substantial number of patients and should be looked for whenever diagnosis and treatment depend on accurate measurements of BP. The importance of an IAD should be better emphasised in current hypertension management guidelines. There is evidence associating an IAD with peripheral vascular disease, raising the possibility that its presence may predict cardiovascular events.

Algorithms↗
PubMed2000

Asthma after childhood pneumonia: six year follow up study.

OBJECTIVE: To establish the long term cumulative prevalence of asthma in children admitted to hospital with pneumonia and to examine the hypothesis that some children admitted to hospital with pneumonia may be presenting with undiagnosed asthma. DESIGN: Prospective study of a cohort of children previously admitted to hospital with pneumonia, followed up by postal questionnaires to their general practitioners and the children or their parents. SETTING: General practices in southwest England. PARTICIPANTS: 78 children admitted to the Royal Devon and Exeter Hospital between 1989 and 1991 with a diagnosis of pneumonia confirmed on independent review of x ray films. MAIN OUTCOME MEASURES: Any diagnosis of asthma, use of any treatment for asthma, and asthma symptom scores. RESULTS: On the basis of a 100% response rate from general practitioners and 86% from patients or parents, the cumulative prevalence of asthma was 45%. A diagnosis of asthma was associated with a family history of asthma (odds ratio 11.23; 95% confidence interval 2.57 to 56.36; P=0.0002). Mean symptom scores were higher for all children with asthma (mean score 2.4; chi(2)=14.88; P=0. 0001) and for children with asthma not being treated (mean 1.4; chi(2)=6.2; P=0.01) than for those without asthma (mean 0.2). CONCLUSIONS: A considerable proportion of children presenting to a district general hospital with pneumonia either already have unrecognised asthma or subsequently develop asthma. The high cumulative prevalence of asthma suggests that careful follow up of such children is worth while. Asthma is undertreated in these children; a structured symptom questionnaire may help to identify and reduce morbidity due to undertreatment.

Adolescent↗
PubMed2000

Prognostic value of cardiac troponin-I levels following catheter-based coronary interventions.

This study has examined the prognostic significance of troponin-I (Tn-I) levels after catheter-based coronary interventions in coronary arteries and saphenous vein grafts lesions. Tn-I and creatine kinase-MB (CK-MB) fraction levels were measured at 6 and 18 to 24 hours after catheter-based coronary intervention in 1,129 consecutive patients with normal preintervention plasma levels of Tn-I, and CK-MB levels below the cutoff for myocardial infarction. Patients were stratified according to maximal postangioplasty Tn-I levels. Group I (n = 784) had no elevated Tn-I (<0.15 ng/ml), group II (n = 170) had Tn-I at 0.15 to 0.45 ng/ml, and group III (n = 175) had Tn-I elevation >0.45 ng/ml. Major in-hospital complications (death, 0-wave infarction, and emergent coronary bypass grafting) and out-of-hospital intermediate-term (8 months) outcomes were compared between the 3 groups. Tn-I elevation >0.45 ng/ml was associated with increased risk of mortality (group III, 1.6%; group II, 0.6%; and group I, 0.1%; p = 0.019) and major in-hospital complications (3.2%, 1.7%, and 0.5%; p = 0.004). There was no difference in death (1.8%, 3.2%, and 2.4%; p = 0.74), Q-wave infarction (0.6%, 0%, and 0.3%; p = 0.66), or target lesion revascularization (10.1%, 9.0%, and 9.3%; p = 0.86) between the 3 groups at follow-up. Cardiac event-free survival was similar between groups (p = 0.3). By multivariate analysis, Tn-I >0.45 ng/ml was an independent predictor for major in-hospital complications (odds ratio 2.1, 95% confidence interval 1.2 to 3.9, p = 0.01). The degree of risk was also associated with the conjoint elevation of Tn-I and CK-MB levels (odds ratio 1.1, 95% confidence interval 1.02 to 1.2, p = 0.01). We conclude that Tn-I levels >3 times the normal limit and conjoint elevation of Tn-I and CK-MB levels after coronary angioplasty are associated with increased risk of major in-hospital complications, but have no incremental risk of adverse intermediate-term (8 months) clinical outcomes.

Aged↗
PubMed2000

Geographic variation in allergic fungal rhinosinusitis.

Allergic fungal rhinosinusitis (AFRS) has a worldwide distribution. This survey of 20 otolaryngologic practices throughout the United States confirmed a variation in the frequency of AFRS relative to endoscopic sinus procedures performed for all other diagnoses. The highest incidence occurred in Memphis, Tennessee at 23%, with three other southern practices reporting a frequency of at least 10%. In the northern locations the frequency ranged from 0 to 4%. No correlation with mould counts was demonstrated, possibly because of incomplete mould data relative to most of the surgical locations.

Humans↗
PubMed2000

School based screening for hypothyroidism in Down's syndrome by dried blood spot TSH measurement.

OBJECTIVE: To determine the feasibility of annual hypothyroid screening of children with Down's syndrome by measuring thyroid stimulating hormone (TSH) on dried blood spots at school, and to describe the outcome in positive children. DESIGN: Establishment of a register of school children with Down's syndrome, and procedures for obtaining permission from parents, annual capillary blood samples, TSH measurement, and clinical assessment of children with TSH values > 10 mU/litre. SUBJECTS: All school age children with Down's syndrome within Lanarkshire and Glasgow Health Boards during 1996-7 and 1997-8. RESULTS: 200 of 214 school children with Down's syndrome were screened. Four of the unscreened children were receiving thyroxine treatment, and only 5 remained unscreened by default. 15 of the 200 children had capillary TSH > 10 mU/litre, and all but 1 had evidence of Hashimoto's thyroiditis. Seven of the 15 children started thyroxine treatment immediately, 6 with a pronounced rise in venous TSH and subnormal free thyroxine (fT4), and one with mildly raised TSH and normal fT4 but symptoms suggesting hypothyroidism. Eight children with mildly raised venous TSH and normal fT4 were left untreated; 1 year after testing positive, fT4 remained > 9 pmol/litre in all cases, but 4 children were started on thyroxine because of a rise in TSH. TSH fell in 3 of the 4 remaining children and there was a marginal rise in 1; all remain untreated. The prevalence of thyroid disease in this population is >/= 8.9%. CONCLUSION: Dried blood spot TSH measurement is effective for detecting hypothyroidism in Down's syndrome and capillary sampling is easily performed at school. The existing programme could be extended to the whole of Scotland within a few years.

Adolescent↗
PubMed1999

Late-developing infection in instrumented idiopathic scoliosis.

STUDY DESIGN: This is a retrospective review of all patients requiring either Cotrel-Dubousset or Moss Miami rod removal. All initial spinal instrumentations were for adolescent idiopathic scoliosis from 1985 through 1994. Twenty-two patients who underwent rod removal for late-developing infection constitute the study group. OBJECTIVES: To determine the bacteriology and treatment of patients with late-developing infection after posterior spinal instrumentation for scoliosis. SUMMARY OF BACKGROUND DATA: There have been conflicting reports regarding this entity, some reporting a high percentage of positive cultures and others a low yield. The latter have attributed the entity to fretting corrosion. Much literature describes late appearance of infection with large foreign bodies (implants). Glycocalyx, a membrane that surrounds bacteria adjacent to surgical implants, results in poor antibiotic penetration, poor macrophage action, and difficulty in culturing bacteria. METHODS: One thousand two hundred forty-seven patients who underwent posterior instrumentation from 1985 through 1994 were reviewed. Those requiring implant removal were further studied. Those with late-developing infection (more than 1 year after the initial procedure) were further reviewed. Culture reports, presence of pseudarthrosis, and antibiotic regimen after implant removal were the primary parameters studied. RESULTS: Twenty-two patients (1.7%) experienced development of late infection a mean of 3.1 years after the initial procedure. In specimens from these patients cultured only 72 hours, only 1 of 10 was positive. Of those cultured for 7-10 days (the last 12) 11 were positive, usually for low-virulence skin organisms. After surgery, patients received antibiotics parenterally for 48 hours and orally for 7 days. All wounds were closed primarily. Four patients had pseudarthroses, two underwent revised procedures with titanium implants without signs of infection at more than 2 years' follow-up. CONCLUSIONS: Late-appearing infection with spinal instrumentation can be treated with device removal, primary skin closure, and short-term oral antibiotics. The infections affect soft tissue, not the bone.

Adolescent↗
PubMed1999

Effects of dopamine and aminophylline on contrast-induced acute renal failure after coronary angioplasty in patients with preexisting renal insufficiency.

In phase 1 of this study, 60 patients undergoing coronary angioplasty were randomized to receive saline, dopamine, or aminophylline; the overall incidence of contrast-induced renal failure was 38%, without difference among the 3 groups. In phase 2 of this study, 72 patients with established contrast-induced renal failure were randomized to receive saline or dopamine; dopamine had a deleterious effect on the severity of renal failure, prolonging the course.

Acute Kidney Injury↗
PubMed1998

Effect of wide posterior release on correction in adolescent idiopathic scoliosis.

Wide lumbar posterior release, consisting of partial excision of spinous process, excision of interspinous ligament and ligamentum flavum, and excision of facet in plane of facet from both outside and within the spinal canal has been employed to increase coronal correction and improve the production of lumbar lordosis (10). Adolescent idiopathic patients with fusion into the lumbar spine were studied. Pre- and postsurgical coronal and sagittal Cobb measurements as well bending measurements were done. Intraoperative biplanar radiographs were done after positioning, after lumbar rod placement, and finally after wide release and placement of the same rod. Statistical analysis was by paired Student's t-test. Significantly (p < 0.005), improved correction was attained in the coronal plane with release (76% vs. 64%). Total lordosis and instrumented segment lordosis was also significantly (p < 0.025) improved with release (12 degrees vs. 3 degrees). Coronal and sagittal plane correction in the lumbar spine is improved significantly with a wide posterior lumbar release.

Adolescent↗
PubMed1992

Thoracolumbar osteotomy for postsurgical sagittal imbalance.

A prospective study of 12 patients with sagittal plane imbalance after multiple surgeries for scoliosis is reported. Reconstruction was attempted by posterior thoracolumbar junction osteotomy. Eighty-seven degrees of thoracic kyphosis (ending at L3) was improved to forty-one degrees (ending at T12). Lumbar lordosis was increased from 21 to 30 degrees, beginning at L1 afterward (L3 before). 8.7 cm posterior displacement of the sagittal weight-bearing axis was achieved. No permanent complications ensued. The procedure, without anterior surgery, corrects the deformity at the apical area. Cotrel-Dubousset instrumentation secured correction and fixation.

Adult↗
PubMed1991

Prevention of the crankshaft phenomenon.

Factors favoring development of the crankshaft phenomenon after posterior spinal fusion include immaturity and large residual deformity. Eight patients at high risk to develop the crankshaft phenomenon underwent periapical anterior growth arrest and fusion before posterior instrumentation and fusion. With follow-up to skeletal maturity, 0% developed crankshaft phenomenon. Anterior growth arrest and fusion before a posterior procedure is recommended in scoliosis patients at high risk to develop the crankshaft phenomenon.

Child↗
PubMed1990

Fusion levels and hook patterns in thoracic scoliosis with Cotrel-Dubousset instrumentation.

This study reports the results of treatment of adolescents with King Types 2, 3, and 4 idiopathic curves using Cotrel-Dubousset instrumentation. Imbalance was seen in Types 2 and 4 curves when distraction direction hook patterns crossing the thoracolumbar junction were employed. Imbalance was not seen when a modified hook pattern employing compressing forces across the thoracolumbar junction was employed. No imbalance was observed in Type 3 curves using the basic right thoracic curve hook pattern. In Type 4 curves, a second modified hook pattern is required to obtain improved correction and balance. The mechanism of production of imbalance is explained by a three dimensional analysis of the deformity and of the forces generated by the Cotrel-Dubousset system.

Adolescent↗