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Biomedical subjects

K R Poskitt

Publications and source records attributed to K R Poskitt.

52 records · Page 3Linked to original sources
PubMed1992

Endoscopic transthoracic sympathectomy: experience in the south west of England.

Thoracic sympathectomy has an established role in the management of primary palmar and axillary hyperhidrosis, Raynaud's phenomenon and occlusive vascular disease. Potential problems with traditional surgical approaches to the sympathetic chain include poor exposure, risk of damage to adjacent structures and postoperative pain. A minimally invasive endoscopic approach helps to overcome these problems. Using this technique, 45 procedures have been performed on 26 patients in two districts in the South West of England over the past five years. Follow-up information was available for 39 procedures. All 27 procedures for hyperhidrosis and both for occlusive vascular disease have produced a long-term improvement. Nine of the 10 procedures for Raynaud's phenomenon have also produced some degree of long-term improvement. Complications included four asymptomatic pneumothoraces, two patients with temporary unilateral Horner's syndrome and two instances of intercosto-brachial numbness. On the positive side, patients expressed satisfaction with the efficacy, rapid recovery and small unobtrusive scars produced by the procedure. Endoscopic transthoracic sympathectomy is effective, safe and well accepted by patients and we believe is now the method of choice for this procedure.

Adolescent↗
PubMed1991

Failure of peripheral arterial balloon angioplasty: does platelet deposition play a role?

The pathophysiological response to peripheral percutaneous transluminal balloon angioplasty in 20 patients was investigated using 111-Indium labelled platelets. Platelet deposition was quantified by measuring the degree of radioactivity uptake at angioplasty and control sites using a computer linked system and expressing the uptake as a ratio of angioplasty/control. Following platelet labelling, scans were performed before angioplasty and at 1, 24 and 48 h after angioplasty. To assess patency of the angioplasty, ankle brachial Doppler pressure indices were performed and supported by repeat angiograms if doubt of patency existed. All patients were followed-up at 1 week, 1 month and 6 months to correlate the degree of early platelet uptake with failure. The mean +/- sem platelet radioactivity ratio at the angioplasty site increased from 1.1 +/- 0.1 prior to the procedure to a peak of 2.1 +/- 0.3 at 1 h (p less than 0.01), 1.6 +/- 0.2 at 24 h (p less than 0.05), and 1.7 +/- 0.3 at 48 h (p less than 0.05). Angioplasties that failed within 6 months tended to have a higher maximum early platelet uptake (3.1 +/- 0.6) compared to successful angioplasties (1.9 +/- 0.3) but the difference was not significant in the numbers studied. This study provides a suitable model to assess the role of platelet accumulation in angioplasty failure and the influence of various antiplatelet regimes.

Adult↗
PubMed1989

Anastomotic aneurysms of the femoral artery: aetiology and treatment.

The aetiology and treatment of 35 femoral false anastomotic aneurysms in 29 patients presenting over the 4-year period 1984-88 were reviewed retrospectively. The mean interval between primary anastomosis and false aneurysm repair was 6 years (range from 2 weeks to 16 years). Twenty-two (63 per cent) false aneurysms had occurred after previous aortobifemoral bypass grafting for occlusive aortoiliac disease. Seven (20 per cent) presented as acute surgical emergencies. Review of the records of the initial operations revealed that superficial wound infections with positive bacteriological cultures had been present in eight cases (23 per cent) and a further two (6 per cent) had lymph fistulae. Thirty-two false aneurysms were repaired, by simple reanastomosis in 14 cases, interposition grafting in 17 cases and in one case by complete revision to an aortobifemoral bypass graft. The risk of a further operative repair was less (P less than 0.05) following interposition grafting, than after simple revision. False aneurysm repairs, when compared with primary reconstructions done during the same period, were associated with more superficial wound infections (37 versus 10 per cent) and more explorations for haemorrhage within 30 days (19 versus 7 per cent).

Anastomosis, Surgical↗
PubMed1989

Abdominal aortic aneurysm repair in the over eighties.

Between January 1980 and September 1988, 34 octogenarians underwent aortic aneurysm repair. There were 26 men and eight women with a median age of 83 years (range 80-88 years). Twenty underwent 'emergency' repair after presenting with pain and/or collapse: 11 with a retroperitoneal rupture, three with an intraperitoneal rupture and six with an expanding aneurysm. The mortality rate for this group was 35 per cent. During the same period 14 patients had an elective repair and there were no deaths within 30 days. The mean hospital stay for the elective group was 14.2 days compared with 17.0 days for survivors in the emergency group. There was no significant difference in terms of risk factors between those who developed postoperative complications and those who did not. These mortality rates compare favourably with our overall mortality results for elective (4.6 per cent) and emergency (31 per cent) surgery. Those patients over 80 years of age with infrarenal abdominal aortic aneurysms should not be refused surgery on the basis of age alone; each patient should be judged individually.

Aged↗
PubMed1988

Pulmonary microembolization in experimental aortic surgery.

Pulmonary dysfunction frequently follows major surgery and has many features identical to "shock lung'. A porcine model of aortic surgery is described in which 111In-labelled platelet kinetics were related to subsequent pulmonary function. In 14 pigs, standardized aortic surgery resulted in reproducible shock and a 50 per cent mortality at 3 days. Cardiac output fell from 2.3 +/- 0.2 to 1.0 +/- 0.1 litres min-1 following removal of the aortic clamp and mean platelet and leucocyte counts fell from 437 +/- 48 to 252 +/- 39 x 10(9) litres-1 and 21.7 +/- 1.5 to 12.9 +/- 1.2 x 10(9) litres-1 respectively (P less than 0.01). Aggregate levels in inferior vena caval blood were maximal at this time and radiolabelled platelets accumulated in the lung with a rise in pulmonary vascular resistance. Alveolar-arterial oxygen difference subsequently increased from initial values of 13.7 +/- 2.0 to 23.4 +/- 3.5 mmHg (P less than 0.01) following resuscitation and to 32.5 +/- 3.4 mmHg at 3 days following surgery (P less than 0.01). This clear sequence suggests that pulmonary platelet microembolization occurs during surgical shock and may be responsible for subsequent pulmonary dysfunction.

Animals↗
PubMed1987

Pinch skin grafting or porcine dermis in venous ulcers: a randomised clinical trial.

Chronic venous ulcers are common, and even with effective compression or elevation large ulcers may take months to heal. Pinch skin grafting may allow healing from epithelial islands throughout the surface area of the ulcer, and a prospective randomised trial was therefore conducted comparing this treatment with porcine dermis dressings. Most patients were treated as outpatients, 25 ulcers being randomised to treatment with pinch skin grafts and 28 to treatment with porcine dermis. Though the groups were well matched, the mean healing rate in the first week was 15 cm2 for pinch skin grafts compared with 3.5 cm2 with porcine dermis (p less than 0.02). By life table analysis 64% of ulcers treated by pinch grafts were healed at six weeks and 74% by 12 weeks compared with 29% and 46% of ulcers, respectively, treated with porcine dermis dressings (chi2 = 4.1; p less than 0.05). All ulcers that failed to heal within 12 weeks included an area posterior to the medial malleolus, where local compression may have been inadequate. Pinch skin grafting improves the rate of healing in large venous ulcers and is a simple technique that may be performed as an outpatient procedure under local anaesthesia.

Bandages↗
PubMed1986

Opsonic dysfunction secondary to plasma fibronectin depletion after aortic surgery.

Fibronectin is a plasma opsonin which is depleted after major injury or surgery. The effect of major aortic surgery on plasma fibronectin has been studied in patients and in an equivalent experimental model in pigs. On the day after aortic surgery in eleven patients mean fibronectin (+/- s.e.m.) had fallen from 363 +/- 11 mg/l pre-operatively to 179 +/- 19 mg/l (P less than 0.01). No such fall was observed in patients undergoing herniorrhaphy. In fourteen pigs aortic surgery produced reproducible surgical shock and a fall in plasma fibronectin from 331 +/- 10 mg/l to 43 +/- 13 mg/l after resuscitation (P less than 0.01). Whenever plasma fibronectin fell below 190 mg/l the circulating free fibronectin was consumed in complexes of 1000 kDa containing collagenous debris. More severe depletion of plasma fibronectin was related to higher concentrations of circulating nonopsonized collagenous debris and to subsequent mortality in pigs. The depletion of free fibronectin that occurs following major surgery may produce clinically important opsonic dysfunction. The clinical relevance of this fibronectin consumption may be missed if measurement is limited to circulating fibronectin levels without determining that proportion bound in complexes and no longer available as an opsonin.

Animals↗
PubMed1986

Effect of the cyclo-oxygenase inhibitor indobufen on platelet accumulation in prosthetic vascular grafts.

An in vivo method of measuring thrombus deposition and pseudo-intimal thickening in prosthetic arterial grafts in an animal model is described. The effect of indobufen, a new cyclo-oxygenase inhibitor, was evaluated and compared to aspirin plus dipyridamole and placebo in 24 greyhounds. Luminal platelet accumulation expressed as thrombogenicity index was 0.33 +/- 0.07 in the placebo group. This was significantly reduced to 0.14 +/- 0.01 by indobufen (P less than 0.05). The reduction to 0.19 +/- 0.04 by aspirin plus dipyridamole failed to achieve statistical significance. Pseudointimal thickness when measured 28 days after implacement was significantly reduced to 21.4 +/- 10.6 per cent by indobufen (P less than 0.01) and 29.4 +/- 10.6 per cent by aspirin plus dipyridamole (P less than 0.02) compared to 75 +/- 10 per cent found in the placebo group. This prosthetic graft model has considerable advantages in the evaluation of potential platelet inhibitory drugs for use in vascular surgery.

Animals↗
PubMed1986

Hypercholesterolaemia accentuates platelet activity.

Platelet aggregation response to collagen has been studied in 20 rabbits, randomly allocated to receive a normal (control) or high cholesterol diet. The sensitivity of platelets to collagen was significantly higher in the hypercholesterolaemic group (p less than 0.01) compared to controls. All hypercholesterolaemic rabbits developed generalised atherosclerosis and this may be due to increased circulating platelet activity.

Animals↗