Biomedical subjects

W Culling

Publications and source records attributed to W Culling.

27 records · Page 2Linked to original sources

PubMed1984

The haemodynamic effects of left ventriculography in coronary artery disease and mitral valve disease: a comparison of high and low osmolality contrast media.

We compared the haemodynamic effects of a low osmolality contrast medium Hexabrix 320 (meglumine/sodium ioxaglate) with a high osmolality medium Urografin 370 (meglumine/sodium diatrizoate) in 32 patients. Each underwent left ventriculography with both media, which caused similar small and transient increases in heart rate and systolic pressure. In 15 patients with coronary artery disease, the mean left ventricular end-diastolic pressure increased by 4 mmHg after hexabrix compared with 10 mmHg after urografin (P less than 0.01); it returned to normal more quickly after hexabrix. Changes after both media did not correlate with baseline end-diastolic pressure, ejection fraction, or extent of coronary artery disease, and thus left ventriculography was unhelpful as a stress test. In 14 patients with mitral stenosis, hexabrix produced a smaller increase in left ventricular end-diastolic pressure (P less than 0.001), left atrial pressure (P less than 0.01) and mitral valve gradient (P less than 0.05) than urografin. Patients preferred the low osmolality medium (P less than 0.01). There was no difference in angiographic quality. We advocate low osmolality contrast media for patients with poor left ventricular function or severe mitral stenosis.

Adult↗

PubMed1984

Haemodynamics and plasma concentrations following sublingual GTN and intravenous, or inhaled, isosorbide dinitrate.

We measured plasma nitrate levels and haemodynamics following sublingual glyceryl trinitrate (GTN) (0.5 mg), or isosorbide dinitrate (ISDN) administered intravenously (0.5 mg) or by inhalation (1.25 mg) in 23 patients undergoing cardiac catheterisation for investigation of chest pain. Peak levels were detected at 90 s and 5 min following intravenous and inhaled ISDN respectively and at 3 min following sublingual GTN. Intravenous and inhaled ISDN produced similar plasma levels at 30 s and both were significantly greater than following sublingual GTN. Plasma levels were maintained for longer following inhaled ISDN than intravenous ISDN or sublingual GTN. Haemodynamic responses were qualitatively similar following each treatment; reduction in pulmonary vascular resistance and pressure and left ventricular end diastolic pressure occurred in each group. Heart rate, cardiac output and LV dP/dt.P-1 remained unchanged. Maximal haemodynamic responses were greater following ISDN than GTN, with little difference between the two preparations of ISDN. Haemodynamic responses were more sustained following inhaled ISDN than following sublingual GTN or intravenous ISDN, the latter two being similar in this respect. These findings suggest that inhaled ISDN may provide more rapid and sustained relief from angina than sublingual GTN.

Absorption↗

PubMed1984

Acute haemodynamic effects of felodipine during beta blockade in patients with coronary artery disease.

The acute effects of felodipine on left ventricular function and haemodynamics were studied in 11 patients with coronary artery disease. To block reflex sympathetic activation due to peripheral vasodilatation and to avoid effects secondary to changes in heart rate all patients received a standard regimen of beta adrenoceptor blockade and all measurements were made during sinus rhythm and right atrial pacing. At 30 minutes after an oral dose (0.075 mg/kg in solution) felodipine plasma concentration were 16.4 (3.5) nmol/l. A significant fall in systemic vascular resistance (30%) and increase in cardiac index (30%) occurred, whereas pulmonary vascular resistance was unchanged. Felodipine increased left ventricular ejection fraction and mean velocity of circumferential fibre shortening but had no effect on derivates of left ventricular pressure (dP/dt or dP/dt P-1) during sinus rhythm or pacing. Thus at the dosage used felodipine was a potent dilator of systemic arterioles but had no direct effect on left ventricular function.

Adult↗

PubMedDate not supplied

A microcomputer system for real-time analysis of cardiac action potentials.

A system for performing real-time analysis of cardiac action potentials has been developed using a microcomputer based on the Motorola 6800 central processor. Transmembrane potentials obtained using standard microelectrodes were digitized to 8 bits at 80 ms intervals, stored in cyclic memory buffer from which they could be selected for analysis, converted back to analogue form and displayed on an oscilloscope in real time. For each action potential, amplitude, the maximum rate of change of potential and the action potential duration at 50% repolarization and 100% repolarization were measured. In addition, conduction time (taken as the interval between the stimulus artefact and the action potential) was measured. All data were stored in memory and later printed, together with the time at which the recording was made. The system was designed for analysis of action potentials recorded using floating microelectrodes. The computer was controlled by three remote switches and a potentiometer, positioned close to the muscle bath. The program was written in Motorola 6800 assembly language and stored in erasable programmable read-only memory.

Animals↗

PubMedDate not supplied

A microcomputer system for analysis of coronary artery calibre and blood flow.

Measurement of myocardial blood flow and assessment of coronary calibre in man has important clinical and research value. An inexpensive microcomputer system has been developed to facilitate analysis of each of these. Coronary sinus and great cardiac vein blood flow are measured using the thermodilution technique. The output of the temperature measurement circuitry is digitized and used to calculate blood flows. For coronary artery calibre measurement, the outline of an arterial segment recorded during coronary arteriography is digitized manually. The microcomputer system provides a graphic display of the digitized artery and calculates diameters throughout its length. Excellent correlations were observed between computer and manual methods for both systems.

Computers↗

PubMedDate not supplied

It's not cricket! Myocardial infarction following non-penetrating blunt chest trauma.

While playing a game of cricket, a 42-year-old man was struck on the chest by the ball. The blunt trauma precipitated a myocardial infarct in the absence of other risk factors or evidence of pre-existing coronary artery disease. Probable pathophysiological mechanisms and potential problems of immediate treatment are discussed.

Adult↗

PubMedDate not supplied

What the SHO saw.

As discussions about junior doctors' training and duty hours continue, we have looked at the actual 'on take' case load and case mix of a medical senior house officer (SHO) in a district general hospital (DGH) over a six-month period. In our DGH, on a one in four rota, exposure to a few common conditions is high and exceeds the minimum requirements for a post to be approved for general professional training. Limited but useful experience may also be gained in the management of many other conditions. The benefits in terms of structured training and lifestyle resulting from the implementation of the Calman report and the junior doctors' hours initiative need to be set against a possible reduction in patient exposure and in the associated opportunities to learn that may occur with a decrease in SHOs' 'front line' exposure.

Education, Medical, Graduate↗

PubMedDate not supplied

The patient focused approach: a better way to run a hospital?

It can take 2 hours of hospital staff time to obtain a routine chest X-ray, up to 47 clinical staff may be involved with a patient during a 5-day stay, and only a quarter of total costs may be for direct patient care, so some hospitals are experimenting with patient focused care by relocating services such as X-ray to the bedside, training ward staff in a wider range of skills, and managing care itself by using multidisciplinary protocols. Potential benefits can be measured in terms of reduced process times and faster turn-round, but duplication of, for example, high-tech pathology and radiology equipment is expensive, as is releasing staff for training. Proponents say that higher quality patient care will result without increased cost, and theoretical analyses suggest that advantages should outweigh disadvantages. The more established patient focused units in the UK are now over a year old; practical analyses of their quality and cost are under way.

Cost-Benefit Analysis↗

PubMedDate not supplied

Ward based X-ray facilities can improve services.

As part of a wider experiment, a satellite X-ray facility, run by 2 part-time radiographers (1 whole time equivalent), was established to provide all plain radiographs on inpatients in a patient focused unit of 114 beds created from 4 medical wards of a 370-bed district general hospital providing acute services to a local population of about 200,000. Fewer staff were needed to provide an X-ray and report on the ward, the number of steps was reduced from 54 to 42 and the time taken from 104 to 62 minutes. Radiographers spent a smaller proportion of their time on professional duties but freed up substantial time for other members of staff. The reactions of all involved, staff and patients, were favourable. With present technology, the patient focused approach brings net benefits and possibly decreases costs, but the balance may swing back to centralisation when picture archiving and communication systems (PACS) become more widely available.

Cost Savings↗