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Biomedical subjects

L T Cotton

Publications and source records attributed to L T Cotton.

At least 37 records · Page 2Linked to original sources
PubMed1983

Raynaud's phenomenon and thermal entrainment: an objective test.

A new objective test for diagnosing Raynaud's phenomenon was assessed in practice. The test is based on entrainment of the thermal vasomotor control system and entails non-invasive measurement of blood-flow responses in one hand while alternating thermal stimuli are applied to the contralateral hand. A significant (p less than 0.001) abnormality of vasomotor control was found in patients with Raynaud's phenomenon compared with normal subjects. When applied clinically this test is diagnostic and indicates the severity of the disease and the effect of treatment.

Adult↗
PubMed1983

Axillofemoral and femorofemoral grafts: a 6-year experience with emphasis on the relationship of peroperative flow measurement to graft survival.

Over a 6-year period 64 axillofemoral bypass and femorofemoral crossover grafts have been performed in 58 patients, most of whom were considered unfit for intra-abdominal surgery. Indications were peripheral ischaemia in 78 per cent and disabling claudication in 22 per cent. The limb salvage rate at 3 years was 75 per cent. No claudicants lost limbs, but only one-third of patients presenting with forefoot gangrene or ulceration avoided amputation. Most patients presenting with ischaemic symptoms at rest had associated femoropopliteal and distal disease, confirmed by the ankle pressure index measurements, and this influenced graft patency. Although the cumulative patency at 3 years for all grafts combined was 57 per cent with similar patencies for both the axillofemoral and femorofemoral grafts, early occlusion was more common in axillofemoral grafts and this may be reduced in bifemoral grafts by the increased flow rate in the vertical limbs. Peroperative electromagnetic flowmeter measurements were made after reconstruction on 55 femoral arteries in 46 of the patients and graft flow velocities were derived from these measurements. Comparison between velocities from those grafts remaining patent and those subsequently occluding showed a high incidence of occlusion in grafts with a maximal velocity after distal vasodilatation of less than 8 cm/s. Graft occlusion after the first postoperative month was more commonly associated with other factors such as continued smoking, severity of distal disease and perigraft infection.

Aged↗
PubMed1983

Per-operative haemodynamic assessment of lower limb arterial surgery. Part 1: Hydraulic impedance measurement.

Hydraulic impedance measurements have been made during surgery on 32 patients undergoing reconstructive arterial surgery. The reconstructive procedures included aorto-iliac, femoro-popliteal and axillo-femoral bypass, and extended deep femoral angioplasty. It was found that in aorto-iliac reconstruction the phase curves provide the means of assessing success, but that in other cases the impedance measurements though showing a similar trend are unable unequivocally to differentiate between success or failure.

Arteries↗
PubMed1982

The measured effect of stopping smoking on intermittent claudication.

One hundred and twenty-four limbs in patients suffering from intermittent claudication were studied over 10 months. Changes in ankle pressure and treadmill exercise tolerance over the period were compared between two groups, one of patients who continued to smoke (group 1) and the other of those who gave up (group 2). Resting ankle systolic pressure fell in smokers' limbs by a mean of 10.2 mmHg (t = 3.56, P less than 0.001), and rose in those patients who stopped smoking by a mean 8.7 mmHg (P = n.s.). Ankle pressures after exercise and maximum treadmill walking distance did not change in smokers but significantly improved in past smokers. Stopping cigarette smoking increased the chance of improvement in ankle pressure and exercise tolerance in intermittent claudication.

Ankle↗
PubMed1979

Haemorrheological response to plasma exchange in Raynaud's syndrome.

Eight patients with Raynaud's syndrome were treated by weekly plasma exchange for four weeks using a Haemonetics Model 30 Blood Processor. The mean whole-blood viscosity at a shear rate of 0.77/s was significantly lower after treatment, and the mean index of red-cell deformability was significantly improved. In four patients studied serially the mean percentage fall in whole-blood viscosity after a single plasma exchange was 49% at 0.77/s but only 14% at 91/s. All patients noticed symptomatic improvement including healing of ischaemic digital ulcers. In six patients the number of digital arterial segments containing detectable blood flow was measured by directional Doppler; in all six the number increased. It is concluded that plasma exchange is an effective means of haemorrheological treatment and may be beneficial in patients with digital ischaemia.

Blood Flow Velocity↗
PubMed1979

Controlled trial of plasma exchange in treatment of Raynaud's syndrome.

Twenty-seven patients with Raynaud's syndrome had their digital vessel patency assessed by Doppler ultrasound after different thermal stresses. Digital vessel patency rates differed significantly after stresses at 15 degrees C and 45 degrees C. In a randomised controlled trial placebo and heparin had no effect either on patients' symptoms or on the patency of their digital vessels. Plasma exchange improved both symptoms and vessel patency rates at 15 degrees C and 21 degrees C. Improvement in seven out of eight of these patients has been maintained for six months. Assessing digital vessel patency by Doppler techniques allow continuous, atraumatic, and safe evaluation of the effects of different methods of treatment on the patency of the digital vessels and has helped to indicate that plasma exchange is a useful adjunct in the management of patients with severe Raynaud's syndrome.

Arteries↗