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Biomedical subjects

A Murray

Publications and source records attributed to A Murray.

At least 433 records · Page 24Linked to original sources
PubMedDate not supplied

The value of continuous ECG monitoring during treatment of diabetic ketoacidosis. A computer study.

In order to confirm or refute the previously held view that electrocardiographic (ECG) abnormalities are frequent in diabetic ketoacidosis, we have undertaken continuous ECG monitoring for 24 h, with subsequent computer analysis, in 14 diabetic patients admitted with severe ketoacidosis. There was a steady fall in heart rate during the 24-h except in 3 severely dehydrated patients. Depression of the ST-segment was minimal and ST-segment height correlated significantly with heart rate, whereas no consistent relationship was found between T-wave amplitude and either heart rate or plasma potassium. Two patients developed short periods of supraventricular ectopic beats. Although ECG monitoring has been claimed to be a useful aid in the management of diabetic ketoacidosis, this study clearly demonstrates that significant ECG changes are rare and ECG monitoring thereafter adds little to careful clinical observation and regular biochemical assessment.

Adolescent↗
PubMedDate not supplied

Prevalence of anaemia in patients with diabetes mellitus.

BACKGROUND: Anaemia is an increasingly recognised entity in patients with diabetes mellitus. AIMS: We aimed to determine the prevalence of anaemia in our population of patients with diabetes, and to examine the factors associated with anaemia. METHODS: The haemoglobin (Hb) levels in a consecutive series of patients attending for annual review of their diabetes over a three-month period were measured. Patients were classified as anaemic as per the WHO criteria. RESULTS: During the period of study, 270 patients attended for review. Eleven per cent of males and 16% of females were anaemic. Seventy four per cent of anaemic patients had a serum creatinine <110micromol/l and 72% of anaemic patients had a calculated creatinine clearance of >60ml/min. CONCLUSIONS: Anaemia was relatively common in patients attending for routine outpatient diabetes clinic review. The high prevalence of anaemia supports the routine screening for anaemia in the diabetes out-patient clinic, including in those without overt nephropathy.

Anemia↗
PubMedDate not supplied

Peripheral laser angioplasty with pulsed dye laser and ball-tipped optical fibres.

Laser angioplasty with the pulsed dye laser and integral ball-tipped optical fibres was used for primary treatment of occlusive femoropopliteal vascular disease in 26 limbs of 24 patients, all of whom warranted operative intervention. 19 had "critical ischaemia", 8 had pedal ulceration, and 4 had distal gangrene. The delivery device consisted of the laser fibre loaded retrogradely into a standard 6 mm balloon angioplasty catheter, and was introduced through a common femoral artery cutdown in an attempt to recanalise femoropopliteal occlusions of a mean length of 21 cm (range 3-49). Angiographic recanalisation was achieved with a mean energy of 250 J (range 38-727 J) in 23 of the 26 limbs; in each case the channel created by the laser fibre was augmented by balloon angioplasty. Technical failure occurred in 3 patients, due to wall dissection, persistent side-branch entry, and incomplete lesion penetration, respectively. Acute occlusion within 48 h occurred in 2 diabetic patients with very poor run-off and distal gangrene, and early failure occurred in another patient due to inadequate balloon dilatation. 1 patient with segmental tibial disease below a technically successful recanalisation did not show clinical improvement. Several patients had coexisting coronary artery disease, 3 of whom died of myocardial infarction--all with patent femoropopliteal vessels. In the 21 survivors, 14 vessels remained patent at a median of 7 months' follow-up.

Aged↗
PubMedDate not supplied

Oscillometric blood pressure devices and simulators: measurements of repeatability and differences between models.

PRIMARY OBJECTIVE: To measure the repeatability and pressure pulse envelope of simulators used for testing oscillometric non-invasive blood pressure (NIBP) devices; to study the effect of different envelopes on NIBP devices, and to measure the difference between NIBP devices due to different oscillometric algorithms. METHODS: Three different models of NIBP simulator and 18 different patient monitors with NIBP function were studied. We developed a pressure measurement system (accuracy 0.048?mmHg) to measure the repeatability of simulators. The effect of changing the envelope was measured by using three simulators with one NIBP device. Differences between 18 NIBP devices were measured using one simulator at seven blood pressure settings. MAIN OUTCOMES AND RESULTS: Simulators generate repeatable pressure pulse envelopes (< 0.2 mmHg) but the magnitude and shape depends on the model of simulator. Oscillometric NIBP devices are highly repeatable (< 2 mmHg) when presented with a repeatable pressure pulse envelope, but different devices employ different algorithms and give different results. For a simulated standard blood pressure setting of 120/80 mmHg, estimates of systolic pressure ranged from 112.6 to 126.6 mmHg (sd of 3.0 mmHg), and diastolic pressure ranged from 74.8 to 86.9 mmHg (sd of 3.5 mmHg). CONCLUSIONS: Simulators and NIBP devices are sufficiently repeatable for clinical use, but further systematic clinical studies are required to better characterize the pressure pulse envelope for different patient groups.

Algorithms↗
PubMedDate not supplied

Mexiletine in the prophylaxis of ventricular arrhythmias during acute myocardial infarction.

In a double-blind study involving 165 patients we examined the role of mexiletine, a new antiarrhythmic drug, for the prophylaxis of ventricular arrhythmias after acute myocardial infarction. Mexiletine or placebo was given orally to patients on arrival in the coronary care unit, and continuous electrocardiographic tape recordings were used to document arrhythmias. Ventricular tachycardia and R-on-T ventricular ectopic beats were significantly reduced in the mexiletine patients, but too few episodes of ventricular fibrillation occurred for statistical comment. When arrhythmias did occur in the mexiletine group, it was usually early in the study, at which time plasma drug levels were low. Adverse effects were uncommon. Patients who were given therapy, but in whom acute myocardial infarction could not be confirmed, suffered no serious consequences of taking mexiletine. The results demonstrate the benefit and limitations of prophylactic oral antiarrhythmic therapy for patients with acute myocardial infarction.

Acute Disease↗
PubMedDate not supplied

External trabeculectomy with T-Flux implant.

PURPOSE: To evaluate the efficacy and safety of T-Flux implant in nonpenetrating glaucoma surgery. METHODS: This clinical interventional case series study included 35 eyes of 35 patients with medically uncontrolled primary open angle glaucoma. External trabeculectomy with T-Flux (ETTF) is a technique of nonpenetrating glaucoma surgery, in which after removing deep scleral tissue and un-roofing the canal of Schlemn (CS) the external trabecular tissue is peeled off to enhance the aqueous drainage without opening the anterior chamber. A non-absorbable T-Flux implant (IOL TECH Laboratories, France) was sutured in deep intrascleral space to keep it patent. Snellen's best-corrected visual acuity, slit lamp biomicroscopy, intraocular pressure (IOP), gonioscopy, funduscopy, and optic disc assessment were performed preoperatively and postoperatively at 1 day, 1 week, and 1, 3 , 6, and 12 months. Visual field testing was performed preoperatively and at 6 and 12 months postoperatively. RESULTS: For three eyes, surgery was converted to standard trabeculectomy owing to the perforation of trabeculo-Descemet's membrane and iris prolapse and excluded from the study. The results of the remaining 32 eyes were included in the study. Preoperative IOP (mean +/- SD) of 32.88 +/- 5.7 mmHg decreased to 15.44 +/- 1.6 mmHg after 12 months. Ten eyes (28.6%) had microhyphema that resolved spontaneously; 3 eyes (8.6%) had microperforation without iris prolapse so ETTF was proceeded routinely. The preoperative number of antiglaucoma medications per patient reduced from (mean +/- SD) 2.74 +/- 0.61 to 0.11 +/- 0.32 postoperatively at 12 months. Visual acuity and visual fields remained stable. CONCLUSIONS: ETTF appears to provide significant control of IOP and have low incidence of complications.

Adult↗
PubMedDate not supplied

Analysis of the temporal compressibility of breast tumour marker assays: development of a "near patient" assay.

The aim of this study was to investigate whether immunoassays for circulating MUC1 antigen in breast cancer could be compressed in time so that serum level results would be made available during the time of the patient's visit to clinic. Two assays were used: -The EMCA (Euro DPC) is a liquid phase immunoassay and the ELSA CA15-3 (CIS) is a double determinant solid phase immunoradiometric assay. The effects of shortened incubation times were investigated by assaying standards and unknown samples and comparing the results with those using the standard kit protocols. The binding kinetics of the monoclonal antibodies employed in the assays were analysed separately. We conclude that the EMCA assay can be shortened to 35 min and we have attributed this to the fast binding kinetics inherent in a liquid phase assay. This shortened assay may produce the basis for a useful "near patient" assay. By comparison, the solid phase ELSA CA15-3 assay cannot be compressed without loss in assay performance.

Antibodies, Monoclonal↗
PubMedDate not supplied

Stability of the human body investigated by sway magnetometry.

A new technique using a pre-calibrated magnetometer has been used to investigate the stability of the human body. Transducer coils were attached to a belt which was worn by the subject. Sway was measured over 30 s periods with eyes open and eyes closed. For 10 normal subjects, the mean sway speed was 3.6 +/- 0.9 mm/s with eyes open, and 5.3 +/- 1.5 mm/s with eyes closed. The mean ratio for eyes open to eyes closed was 0.68 +/- 0.10. The test was simple to perform and gave reproducible results.

Adult↗
PubMedDate not supplied

Comparison of three arterial pulse waveform classification techniques.

Peripheral pulse waveforms can become stretched and damped with increasing severity of peripheral vascular disease (PVD) and hence could provide valuable diagnostic information. This study compares the diagnostic performance of 3 established classification techniques (a linear discriminant classifier, a k-nearest neighbour classifier, and an artificial neural network) for the detection of lower limb arterial disease from pulse waveforms obtained using photoelectric plethysmography (PPG). Pulse waveforms and pre- and post-exercise Doppler ultrasound ankle to brachial pressure indices (ABPI) were obtained from patients attending a vascular measurement laboratory. A single PPG pulse from each big toe was recorded direct to computer, pre-processed, and then used as classifier input data. The correct classifier outputs were the corresponding ABPI diagnostic classification. Pulse and ABPI measurements from 100 legs were used as training data for each classifier, and the computed classifications for pulses from a further 266 legs were then compared with their ABPI diagnoses. The diagnostic accuracy of the artificial neural network (80%; was higher than for the optimized k-nearest neighbour classifier (k = 27, accuracy 76% and the linear discriminant classifier (71%). The Kappa measure of agreement which excludes chance was highest for the artificial neural network (57%) and significantly higher than that of the linear discriminant classifier (Kappa 40%, p < 0.05). The value of Kappa for the optimized k-nearest neighbour classifier (k = 27) was intermediate at 47%. This study has shown that classifiers can be taught to discriminate between small, and perhaps subtle, differences in features. We have demonstrated that artificial neural networks can be used to classify arterial pulse waveforms, and can perform better overall than k-nearest neighbour or linear discriminant classifiers for this application.

Ankle↗
PubMedDate not supplied

Word deafness presenting as a sudden hearing loss.

Sudden hearing loss is a condition frequently seen in ENT departments and is usually due to otological pathology. We present a patient who described symptoms of a sudden inability to hear but who, on further questioning and investigations, had 'word deafness' due to bilateral temporoparietal infarcts. We discuss the clinical syndromes associated with these infarcts and the specific management of word deafness.

Cerebral Infarction↗
PubMedDate not supplied

Value of echocardiographic determination of isovolumic relaxation time in the detection of heart transplant rejection.

The reproducibility of the measurement of isovolumic relaxation time in heart transplant recipients was assessed in eight heart transplant recipients. The value of routine measurement of isovolumic relaxation time and fractional shortening by echocardiography in the diagnosis of rejection was assessed by comparison with endomyocardial biopsy results in 12 patients. Despite a large, unexplained variability that will limit the application of the test in the individual patient, there was a significant fall in isovolumic relaxation time with moderate to severe rejection.

Echocardiography↗