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Biomedical subjects

C P Shearman

Publications and source records attributed to C P Shearman.

At least 55 records · Page 3Linked to original sources
PubMed1993

Adjuvant prostanoid treatment during femorodistal reconstruction.

A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effect of prostacyclin analogue iloprost on haemodynamic parameters during femoro-crural reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, graft blood flow and mean systemic arterial blood pressure (MABP) during femoro-crural arterial bypass. 3000ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 40% (4-80%) (P less than 0.01, Wilcoxon). Decreased peripheral resistance persisted to 20 minutes. Graft flow during the same period increased by 52% (-7 to 294%) (P less than 0.01). A transient maximal drop in mean MABP of 22% from 83-65 mmHg occurred 5 minutes post iloprost infusion but caused no detrimental effects and recovered to baseline values by 10 mins. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1992

Iloprost reduces peripheral resistance during femoro-distal reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effect of iloprost, a stable prostacyclin mimetic, on peripheral resistance during femoro-distal bypass. Patients undergoing femoro-distal long saphenous vein bypass for critical ischaemia received 3000 ng of iloprost or placebo infused into the graft via an unligated side branch over 2 min. Graft blood flow and peripheral resistance were measured for 20 min, using an operative Doppler flowmeter (OpDop 130, SciMed, U.K.) and a pressure transducer to record graft pressure. Postoperatively, graft blood flow was assessed by daily duplex ultrasound for 7 days. Iloprost produced an immediate drop in peripheral resistance in all cases (n = 18) by a mean (range) of 40% (4-80%) compared with controls (n = 15) in whom there was a 5.3% (-8 to +36%) increase in resistance (p less than 0.01, Wilcoxon test). Decreased peripheral resistance in iloprost-treated patients persisted to 20 min. The largest decreases in peripheral resistance occurred in patients with the highest initial resistances (r = 0.56, p less than 0.02). Graft flow during the same period increased by 52% (-7 to 294%) compared with controls in whom there was a 6% (-17 to 26%) increase in flow, (p less than 0.01). Flow remained elevated by 53% over baseline values at 1 week post-infusion in the iloprost-treated group but this did not achieve statistical significance compared to controls in whom flow also increased by 13%. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1992

Pharmacological manipulation of peripheral resistance during distal vascular reconstruction.

A randomised placebo-controlled trial was conducted to investigate the effects of iloprost, a stable prostacyclin analogue, on peripheral resistance, during femoro-crural arterial bypass. 3000 ng of iloprost, infused into the graft, produced an immediate drop in peripheral resistance by a mean (range) of 43% (4-80%; p less than 0.01, Wilcoxon). Decreased peripheral resistance persisted to 20 minutes. Graft flow during the same period increased by 59.8% (-7 to 294%; p less than 0.01) and this increase persisted after the operation. Iloprost produces an immediate decrease in peripheral resistance associated with a prolonged increase in graft blood flow. This may reduce graft failure in the early postoperative period.

Aged↗
PubMed1992

Peripheral pulse palpation: an unreliable physical sign.

Fifty observers, including two fully trained vascular surgeons, were asked to determine the presence or absence of the femoral and distal pulses of four patients with peripheral vascular disease and one asymptomatic subject (50 pulses assessed). Pulses felt by both vascular surgeons were deemed to be palpable. Among the other observers, the sensitivity of palpation was 95% or over for the femoral pulse, but 33% to 60% for observers of varying experience feeling for the posterior tibial pulse. Up to 20% false-positive observations were reported. Disease was diagnosed in over 10% of examinations of healthy limbs and was missed in over 10% of symptomatic limbs. The accuracy of pulse palpation was strongly correlated with the systolic blood pressure in the underlying artery. Accuracy was greater among more experienced observers, suggesting that careful teaching of this skill is likely to be beneficial. Even so, pulse palpation alone is an unreliable physical sign and should only be used in combination with objective measurements as a guide to clinical management.

Blood Pressure↗
PubMed1991

Aggressive arterial reconstruction for critical lower limb ischaemia.

A consecutive series of 315 patients underwent arterial reconstruction for 329 critically ischaemic lower limbs over a 5-year period. Patients were not excluded from limb salvage surgery on the basis of poor run-off on preoperative angiography. Femorocrural bypass to a single calf vessel was required in 239 limbs (73 per cent); the 30-day cumulative mortality rate was 7 per cent, rising to 41 per cent at 5 years. Cumulative graft patency at 30 days, 1 year, 2 years and 5 years was 96, 85, 84 and 82 per cent respectively and was independent of the level of reconstruction. In situ long saphenous vein was the conduit of choice for distal bypass but, when this was absent, satisfactory results were obtained with arm vein or composite vein grafts. Acceptable results can be obtained for reconstructive surgery without preoperative angiographic selection of patients. An aggressive approach to limb salvage is therefore justified.

Aged↗
PubMed1991

Iloprost improves femoro-distal graft flow after a single bolus injection.

A double-blind, randomised, placebo-controlled trial was conducted to study the effect of the stable prostacyclin analogue iloprost on femoro-distal graft blood flow. After completing femoro-distal reconstruction, 3000 ng of iloprost or placebo was injected into the graft over 2 min. Graft blood flow, measured by electromagnetic flowmetry, increased by a mean (range) of 94% (12 to 192%) in patients receiving iloprost (n = 15) compared to 6% (-34 to 53%) in controls (n = 16; p less than 0.0001, t-test). Increased graft flow, measured by duplex ultrasound, was maintained in the iloprost group over a 7 day period postoperatively (F = 5.2, p = 0.03; analysis of variance) and remained higher at 7 days (p = 0.007, t-test). Iloprost produces an immediate, sustained increase in graft blood flow after femoro-distal reconstruction and may therefore be of benefit in reducing the incidence of early graft failure.

Aged↗
PubMed1990

Effect of surgery on the systemic inflammatory response to intermittent claudication.

The hypothesis that intermittent claudication initiates a systemic inflammatory response was investigated by studying the effect of exercise on markers of neutrophil activation and vascular permeability in 25 claudicants and 10 controls. Urinary albumin excretion, previously demonstrated to reflect vascular permeability, increased significantly after exercise in claudicants and was associated with decreased neutrophil filterability and increased serum lysozyme activity. No similar exercise-induced changes were seen in controls or in claudicants after successful arterial bypass surgery. These results suggest that intermittent claudication is associated with potentially deleterious systemic manifestations that are surgically reversible.

Aged↗
PubMed1990

Femoro-distal graft flow augmentation with the prostacyclin analogue iloprost.

The possible application of the prostacyclin analogue Iloprost to improve the results of arterial surgery has been studied. On completion of femoro-distal reconstruction, intra-graft administration of Iloprost caused an increase in graft blood flow measured by electromagnetic flowmetry. Three thousand nanograms of the drug appeared to be the optimum dose and in 10 patients who received this amount the graft blood flow increased from a mean of 117.6 ml/min to 225.5 ml/min (P less than 0.01, Wilcoxon), a mean (range) increase of 127.9% (54-190) after 20 min. Iloprost requires further evaluation, but may be a useful adjunct to femoro-distal reconstruction.

Aged↗
PubMed1990

Assessment of intermittent claudication by quantitation of exercise-induced microalbuminuria.

Urinary albumin excretion rates, expressed as albumin-creatinine ratios (ACR, mg/mmol) were measured before and after exercise in 23 claudicants and 10 controls. The mean (range) resting ACRs in the claudicants and controls were 4.42 (0.2-34.6) and 0.77 (0.3-2.8) respectively (P less than 0.001). ACR increased after exercise by a mean of 153% in claudicants to 9.7 (0.2-48.1; P less than 0.001) with no change in controls, 0.79 (0.2-2.1). In patients with claudication there was a positive correlation between ankle pressure recovery time and the relative increase in ACR after exercise (r = 0.64, P less than 0.01). The post-exercise increase in ACR was reduced in all nine patients who underwent bypass surgery. Measurement of ACR after exercise appears to be related to severity of muscle ischaemia and may assist in the assessment of patients with intermittent claudication.

Aged↗
PubMed1989

Is low proteinuria an early predictor of severity of acute pancreatitis?

Serial six hourly urine collections were made for seven days on 20 patients with acute pancreatitis. Quantitative immunoassay of urinary albumin and IgG on the first urine sample after admission showed increased excretion rates in 14 and 13 patients, respectively. Urinary protein excretion rates remained normal or approached normal by seven days in 17 patients who made uneventful recoveries. The maximum urinary excretion rates of both albumin and IgG within the first 36 hours correlated with the serum C-reactive protein concentration 72 hours after admission. The highest IgG excretion rates were found in three patients who later developed severe complications. These preliminary data suggest that low proteinuria is a very early response in acute pancreatitis, and that it may reflect the severity of inflammation.

Acute Disease↗