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Biomedical subjects

R K Vohra

Publications and source records attributed to R K Vohra.

At least 19 recordsLinked to original sources
PubMed2005

The effects of hydroxyethyl starch compared with gelofusine on activated endothelium and the systemic inflammatory response following aortic aneurysm repair.

OBJECTIVE: To investigate the effect of HES, used as a plasma volume expander, on endothelial cell activation induced by ischaemia-reperfusion in humans. MATERIAL AND METHODS: Forty patients undergoing elective infrarenal aneurysm repair were randomised to receive either gelatine or hydroxyethyl starch solution as plasma expanders. The anaesthetic technique was standardised. All patients received the same crystalloid as per standard protocol. Urine samples and blood samples were collected at various times for assessment of microalbuminuria and von Willebrand factor (vWf) and CRP. RESULTS: The peak C-reactive protein was significantly lower in the patients treated with HES than those treated with gelofusine [142 mg/L (113,196 mg/L) vs 246 mg/L (189,291 mg/L) mg/L, P < 0.01, Mann-Whitney test]. The peak ACR was also significantly lower in the HES treated patients (9.3 mg/mmol vs 23.3 mg/mmol, P < 0.05). The plasma level of vWf was significantly higher in the gelofusine treated patients than those treated with HES [173.5 U/dl Vs 80.5 U/dl, P < 0.001, at 4 hr; 160 U/dl Vs 82.5 U/dl, P < 0.001, at 8 hr; 191 U/dl Vs 100.5 U/dl, P < 0.001, at 12 hr; 209 U/dl Vs 81.0 U/dl, P < 0.001, at 24 hr]. CONCLUSION: HES may damp down the systemic inflammatory response and reduce endothelial cell dysfunction.

Aged↗
PubMed2004

Randomized study comparing the effects of hydroxyethyl starch solution with Gelofusine on pulmonary function in patients undergoing abdominal aortic aneurysm surgery.

BACKGROUND: Restoring blood flow to ischaemic tissue can cause lung damage with pulmonary oedema. Hydroxyethyl starch (HES) solution, when used for volume replacement, may modify and reduce the degree of ischaemia-reperfusion injury. We compared the effects of HES solution with those of Gelofusine solution on pulmonary function, microvascular permeability and neutrophil activation in patients undergoing elective infrarenal abdominal aortic aneurysm surgery. METHODS: Forty patients were randomized into two groups. The anaesthetic technique was standardized. Lung function was assessed with the PO(2)/FI(O(2)) ratio, respiratory compliance, chest x-ray and a score for lung injury. Microvascular permeability was determined by measuring microalbuminuria. Neutrophil activation was determined by measurement of plasma elastase. RESULTS: Four hours after surgery, the median (quartile values) PO(2)/FI(O(2)) ratio was 40.3 (37.8, 53.1) kPa for the HES-treated patients compared with 33.9 (31.2, 40.9) kPa for the Gelofusine-treated patients (P<0.01, Mann-Whitney test). The respiratory compliance was 80 (73.5, 80) ml cm(-1) H(2)O in the HES-treated patients compared with 60.1 (50.8, 73.3) ml cm(-1) H(2)O in the Gelofusine-treated patients (P<0.01, Mann-Whitney test). The lung injury score 4 h after surgery was less for the patients treated with HES compared with the patients treated with Gelofusine (0.33 vs 0.71, P=0.01, Wilcoxon rank sum test). Mean (SD) plasma elastase was less in the HES-treated patients on the first postoperative day (1.96 (0.17) vs 2.08 (0.24), P<0.05). The log mean microalbuminuria was less in the HES-treated patients (0.41 vs 0.91 mg mmol(-1), P<0.05). This difference in microvascular permeability was associated with different volumes of colloid required to maintain stable cardiovascular measurements in the two groups of patients studied (3000 vs 3500 ml, P<0.01, Mann-Whitney test). CONCLUSION: Compared with Gelofusine, the perioperative pulmonary function of patients treated with HES after abdominal aortic aneurysm surgery was better.

Aged↗
PubMed2003

Microtibial embolectomy.

BACKGROUND: microtibial embolectomy is an important technique in cases of limb threatening acute arterial occlusion affecting native crural and pedal vessels. It is particularly useful when thrombolysis is contraindicated or ineffective as in "trash foot". METHODS: in order to evaluate the efficacy of this technique, a retrospective case note review was carried out for patients undergoing microtibial embolectomy from 1990 to 1999. Data collected included the causes and degree of ischaemia, additional procedures required, vessel patency, limb salvage and complications encountered. RESULTS: twenty-two limbs underwent exploration of the crural/pedal vessels with ankle level arteriotomies under local anaesthetic in 12 cases, general anaesthetic in nine and epidural in one. The causes of ischaemia were cardiac emboli (8), "trash foot" (7), emboli from aortic and popliteal aneurysms (3) and thrombotic occlusion of crural vessels (4). The vessel patency rate was 69% and limb salvage rate 62% (13/21) up to 5-years follow-up. Six of the seven cases with "trash foot" were salvaged while one required an amputation at 3-months post-operatively. The 30-day mortality was 22% (5/22). CONCLUSIONS: microtibial embolectomy is effective in acute occlusion of the crural/pedal arteries including cases of "trash foot", offering limb salvage to a worthwhile proportion of cases.

Aged↗
PubMed2003

The efficacy of aspirin in patients undergoing infra-inguinal bypass and identification of high risk patients.

AIM: Infrainguinal bypass is an effective treatment for critical lower limb ischemia but up to 1/3 of these grafts will occlude within the 1st year. The aim of this audit was to evaluate the efficacy of aspirin in maintaining graft patency and also improving patient survival. METHODS: In a single audited year (1997) 125 bypasses were carried out. Seventy-nine were on aspirin, 34 on no treatment and 12 were on other agents and hence excluded from analysis. The indication for surgery was critical ischaemia in 101 and disabling claudication in 12. Autologous vein was used in 104 and prosthetic grafts in 9. RESULTS: The overall 2-year primary graft patency, secondary graft patency and limb salvage were 50%, 71% and 83%, respectively. The 2-year secondary patency in patients with or without aspirin was 73% and 64%, respectively (p<0.12-log rank test). The corresponding patient survival from vascular death in the 2 groups was 73% and 70% (p<0.67-log rank test). Crural/ pedal bypass (51/75 on aspirin) and smoking (51/61 on aspirin) were independent risk factors for graft failure and vascular death respectively whilst those with a previous myocardial infarct (21/28 on aspirin) reached significance in univariate analysis only (p< 0.03). CONCLUSION: Aspirin was not a significant factor in preventing graft failure or vascular death in patients undergoing bypass for critical limb ischemia. Dual therapy with other antiplatelet agents needs to be considered in such patients particularly those undergoing crural/pedal bypass, smokers and those with a history of previous myocardial infarction.

Adult↗
PubMed2002

Splanchnic oxygenation in patients undergoing abdominal aortic aneurysm repair and volume expansion with eloHAES.

BACKGROUND: Gastric intramucosal pH (pHi), a surrogate marker of splanchnic oxygenation, falls following abdominal aortic aneurysm surgery. AIM: To investigate the effects of volume expansion with hydroxyethyl starch (eloHAES) on splanchnic perfusion compared to another colloid such as gelofusine. PATIENTS AND METHODS: Twenty-two consecutive patients undergoing AAA repair were randomised to receive either eloHAES or gelofusine as plasma expanders. Tissue oxygenation was monitored (10 gelofusine and 12 eloHAES) indirectly by measuring pHi using a nasogastric tonometer. RESULTS: Compared to the eloHAES group, the fall in pHi was significantly greater in the gelofusine group at clamp release (7.29 vs 7.33, P=0.003) and at 4 h following clamp release (7.29 vs 7.33, P=0.03). There was a good inverse correlation between the lowest pHi and the peak serum interleukin-6 (r(s)= -0.47, P=0.03). By multivariate analysis, the only factor that influenced the pHi was the type of colloid used (F=5.54, P=0.005). The eloHAES treated patients required significantly less colloid on the first postoperative day (3175 +/- 175 vs 4065 +/- 269 ml, P=0.01). CONCLUSION: In patients undergoing abdominal aortic aneurysm repair, plasma expansion with eloHAES improves microvascular perfusion and splanchnic oxygenation.

Aged↗
PubMed2001

The non-ischaemic blue finger.

Finger discoloration may result from recognized conditions affecting upper limb vasculature. We describe 11 patients who presented with acute pain, swelling and blue/purple discoloration in a finger. This benign condition mimicked digital ischaemia. There were 9 women and 2 men. The episode usually started with an ache/pain in the finger followed 2-3 h later by a blue/purple discoloration primarily on the volar aspect but always sparing the tip. This completely resolved after 4-7 days with no residual deficit. There was no history of trauma. Four patients had had previous episodes--2 had been started on warfarin. There was no family history and only one gave a history of spontaneous bruising of her legs. Examination of all patients--pulse rate, blood pressure, cardiac and subclavian artery auscultation and digital artery Doppler insonation--was normal. All patients had normal full blood counts, CRP, vasculitis screen and clotting (except those on warfarin). Six similar cases, all women, were reported in 1982. There was no common aetiological factor other than sex. Although of no prognostic significance, the condition is likely to concern patients and doctors in primary care. The discoloration is, however, clearly of a different distribution to that in an ischaemic finger where the tip of the digit is involved.

Acute Disease↗
PubMed1994

Pressure sores.

Explore the source record for details and available documents.

Humans↗
PubMed1991

True profunda femoris aneurysms: are they more dangerous than other atherosclerotic aneurysms of the femoropopliteal segment?

Three cases of true aneurysms of the profunda femoris artery are reported along with a review of 17 other cases in the literature. These aneurysms are rare and commonly present with rapid enlargement or rupture (9/20), the risk of rupture being higher than those affecting the femoral or popliteal arteries. All patients underwent successful surgical treatment except for one who required amputation. The diagnosis of an aneurysm of the profunda femoris artery must be considered in all patients with a pulsatile swelling in the groin. Surgical treatment is mandatory, and it carries a low mortality as well as a low risk of amputation.

Aged↗
PubMed1991

Adult human endothelial cell seeding using expanded polytetrafluoroethylene vascular grafts: a comparison of four substrates.

Prosthetic small-caliber vascular grafts give poorer patency rates than autogenous vein grafts, possibly because the former never spontaneously form endothelium. Animal studies have shown that endothelialization of prosthetic grafts can be encouraged by seeding endothelial cells into the graft at the time of surgery, resulting in improved patency. Information regarding the attachment characteristics of adult human endothelial cells to prosthetic grafts is, however, sparce. Laboratory experiments were performed by use of cell culture techniques to compare the attachment characteristics of adult human endothelial cells to expanded polytetrafluoroethylene graft material, both untreated and treated, with one of four protein substrates--preclotted blood, fibronectin, laminin, and type 4 collagen. Attachment characteristics were compared quantitatively by use of attachment assays and qualitatively by scanning electron microscopy. Attachment to untreated expanded polytetrafluoroethylene was poor but could be greatly improved by preclotting or precoating with any of the proteins, particularly fibronectin. In preclotted grafts seeded endothelial cells formed a virtually confluent monolayer after 1 hour. Cell attachment to the other grafts coated with protein was patchy and inconsistent. It is concluded that a rapid confluent endothelial lining within a prosthetic vascular graft is possible, and of the substrates examined, preclotted blood best encourages cell attachment to expanded polytetrafluoroethylene.

Blood Vessel Prosthesis↗
PubMed1990

Effects of shear stress on endothelial cell monolayers on expanded polytetrafluoroethylene (ePTFE) grafts using preclot and fibronectin matrices.

Animal studies have shown that endothelial seeding of vascular prosthetic grafts reduces thrombogenicity and improves their patency. However, for endothelial seeding to be of clinical benefit in humans, it must withstand shear stress of blood flow. Endothelial cells labelled with Indium-111-oxine were seeded in supra-confluent densities on preclot or fibronectin coated ePTFE graft segments over a period of 90 min. These grafts with rapidly formed endothelial cell monolayers were then exposed to varying shear stresses up to a flow rate of 300 ml/min, using tissue culture medium in an artificial flow circuit. Grafts coated with preclot matrix showed 2 h cell retentions of 82.4 +/- 6.8% at 25 ml/min, 79.9 +/- 8.2% at 100 ml/min, 75.4 +/- 9.5% at 200 ml/min and 58.3 +/- 15.5% at 300 ml/min whilst those for the fibronectin matrix were 57.8 +/- 9.9%, 55.2 +/- 13.3%, 55.4 +/- 12.9% and 56.5 +/- 15.2% respectively. Overall the preclot matrix was found to be better than fibronectin (P less than 0.001). Light and scanning electron microscopy revealed well-formed endothelial cell monolayers retained on preclot matrix up to a flow rate of 200 ml/min whereas uncovered patches were seen at 300 ml/min and at all flow rates on fibronectin matrix.

Blood Coagulation↗
PubMed1990

Fibronectin coating of expanded polytetrafluoroethylene (ePTFE) grafts and its role in endothelial seeding.

Although fibronectin's role as a matrix to improve endothelial seeding has been demonstrated by other workers, the optimum concentration for use has never been described. Attachment of fibronectin to expanded polytetrafluoroethylene (ePTFE) was measured, using 125I-radiolabeled protein, at different concentrations and for different time periods. The absolute amount of fibronectin bound to the graft increased with the concentrations used in coating (p less than 0.001) and also with time (p less than 0.01); e.g., at 50 micrograms/ml, 90 min of incubation produced a molecular attachment of 4.0 x 10(11)/cm2 of graft. However, its percentage attachment decreased with a rise in concentration (p less than 0.001). After an initial loss of 22% in 30 min, the fibronectin-graft bond was found to be stable when exposed to a shear stress produced by flow at 200 ml/min. No significant difference in the cell adherence could be found in grafts coated with fibronectin concentrations of 50, 150, and 250 micrograms/ml, although it was significantly less at 10 and 25 micrograms/ml (p less than 0.05).

Blood Vessel Prosthesis↗
PubMedDate not supplied

Combined intravenous and oral pentoxifylline in the treatment of peripheral vascular disease. A clinical trial.

Sixteen patients with severe occlusive vascular disease of the lower extremities were randomised to receive a five day course of combined intravenous and oral Pentoxifylline followed by three months oral treatment only, or identical treatment with a matching placebo. Nine patients received active Pentoxifylline, and 7 placebo, Follow-up by regular clinical examination and haemoreological assessment revealed a marked improvement in claudication distance and an increase in red cell deformability in those receiving Pentoxifylline, there being no change in those receiving placebo. Although both of the above parameters were improved by the treatment, there did not appear to be a direct correlation between red cell deformability and claudication distance in individual patients. A combination of intravenous and oral Pentoxifylline therapy results in an increase in both claudication distance and red cell deformability, but the former may not te a direct consequence of the latter.

Administration, Oral↗