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Biomedical subjects

N Chalmers

Publications and source records attributed to N Chalmers.

At least 19 recordsLinked to original sources
PubMed2005

A cross-site vascular radiology on-call service: the Manchester experience.

AIM: A cross-site vascular radiology on-call service was established 5 years ago to cover two vascular centres in Manchester. We aimed to review the service. MATERIALS AND METHODS: A prospective audit of out-of hours referrals and procedures over a three month period (March-May 2003) was undertaken. RESULTS: There were 52 incidents in 49 patients (mean 4 calls per week). Nine involved telephone advice only, the remainder (82%) required a procedure. Angiography was performed on 88% of patients and therapeutic radiological intervention on 50%. 71% of calls occurred at a weekend. 50% of the calls were from vascular surgery and 50% from other sources. The consultant vascular radiologist was present for 93% of procedures. CONCLUSIONS: The workload suggests that a vascular radiology on call service is justified in Manchester. There have been no major problems with its implementation and operation. This is a consultant led service, with very few cases being devolved to a specialist registrar (SpR).

After-Hours Care↗
PubMed2003

Proximal arterial occlusion protects the distal lower limb vessels.

PURPOSE: To test the hypothesis that chronic arterial occlusion protects the distal vessels from disease progression. METHODS: Peripheral angiograms from the radiology film store filed under 1997-1999 were reviewed. Those showing unilateral iliac occlusion and those showing unilateral femoro-popliteal occlusion were selected. The severity of arterial disease distal to the occlusion was compared with the patent side. Subsequently, in a subgroup of patients undergoing repeat angiography, the frequency and distribution of disease progression was recorded and related to the initial disease distribution. RESULTS: In the presence of a unilateral iliac occlusion, femoro-popliteal occlusion was less likely on the side of the iliac occlusion than on the opposite side (difference in proportion 10%. 95% C.I.: 1-18%). In the presence of a unilateral occlusion proximal to the knee joint, there were more patent calf vessels on the side of the occlusion than on the opposite side (difference in proportion 9%. 95% C.I.: 4-14%). When angiography was repeated, progression of calf vessel disease was less common in the limbs with untreated proximal occlusion than in those with no proximal occlusion. CONCLUSION: Proximal arterial occlusion protects the distal vessels from the risk of progressive arterial disease.

Angiography, Digital Subtraction↗
PubMed2003

Modelling the influence of irrigation abstractions on Scotland's water resources.

Legislation to control abstraction of water in Scotland is limited and for purposes such as irrigation there are no restrictions in place over most of the country. This situation is set to change with implementation of the European Water Framework Directive. As a first step towards the development of appropriate policy for irrigation control there is a need to assess the current scale of irrigation practices in Scotland. This paper presents a modelling approach that has been used to quantify spatially the volume of water abstractions across the country for irrigation of potato crops under typical climatic conditions. A water balance model was developed to calculate soil moisture deficits and identify the potential need for irrigation. The results were then combined with spatial data on potato cropping and integrated to the sub-catchment scale to identify the river systems most at risk from over-abstraction. The results highlight that the areas that have greatest need for irrigation of potatoes are all concentrated in the central east-coast area of Scotland. The difference between irrigation demand in wet and dry years is very significant, although spatial patterns of the distribution are similar.

Agriculture↗
PubMed2002

Evaluation of angiography performed by radiographers and nurses.

AIM: To evaluate out-patient angiography performed by nurses and radiographers. MATERIALS AND METHODS: A protocol for out-patient angiography performed by nurses and radiographers was drawn up and approved by the Trust's Risk Management Committee. Following training, two experienced radiographers and one nurse undertook elective peripheral or renal angiography according to the protocol on 187 patients. Angiograms were performed using a 3F catheter introduced into the abdominal aorta from a femoral approach. Patients were discharged after 2 hours and contacted by telephone the following morning. RESULTS: No patient refused consent for the procedure. One hundred and seventy-two patients underwent successful catheterization without assistance from a radiologist. Radiologist assistance was required with femoral puncture or catheter/guidewire manipulation in 15 cases (8%). Images were considered diagnostic by the reporting radiologist in all but one case. This patient was recalled for further aortogram and pressure measurements. There was a single puncture site complication due to transient stenosis of the common femoral artery at the puncture site. This is thought to have been the result of subintimal injection of local anaesthetic, and it resolved spontaneously over 30 minutes. There were no delayed complications. CONCLUSION: Experienced nurses and radiographers can rapidly acquire the skills to perform diagnostic angiography safely and efficiently.

Allied Health Personnel↗
PubMed2001

Peripheral arterial disease in diabetic and nondiabetic patients: a comparison of severity and outcome.

OBJECTIVE: The aim of this study was to quantify the distribution of peripheral arterial disease in the diabetic and nondiabetic population attending for angiography and to compare severity and outcome between both groups of patients. RESEARCH DESIGN AND METHODS: Randomly selected lower-extremity angiograms were examined according to the Bollinger system. Patient demographics and medical history were recorded and case notes were examined to determine which patients later underwent a revascularization procedure or amputation and which patients had died. RESULTS: A total of 136 arteriograms obtained between 1992 and 1996 were analyzed. The age (mean +/- SD) of the patients was 64.7 +/- 10.8 years. Diabetic patients (43%) and nondiabetic patients were of similar age (63.9 +/- 10.4 vs. 65.3 +/- 11.1 years, P = 0.43), with a similar history of smoking (81.0 vs. 76.9%, P = 0.26), ischemic heart disease (41.4 vs. 37.2%, P = 0.54), and hypercholesterolemia (24.4 vs. 30.8%, P = 0.48). However, there were a greater proportion of hypertensive patients in the diabetic group (63.8 vs. 39.7%, P = 0.006). Diabetic patients had greater severity of arterial disease in the profunda femoris and all arterial segments below the knee (P = 0.02). A greater number of amputations occurred in the diabetic group: diabetic patients were five times more likely to have an amputation (41.4 vs. 11.5%, odds ratio [OR] 5.4, P < 0.0001). Mortality was higher in the diabetic group (51.7 vs. 25.6%, OR 3.1, P = 0.002), and diabetic patients who died were younger at presentation than nondiabetic patients (64.7 +/- 11.4 vs. 71.1 +/- 8.7 years, P = 0.04). CONCLUSIONS: In patients with peripheral arterial disease, diabetic patients have worse arterial disease and a poorer outcome than nondiabetic patients.

Aged↗
PubMed2000

Early mobilization following angioplasty.

AIM: To assess the incidence of puncture site complications in in-patients undergoing early mobilization following angioplasty with a view to performing day case angioplasty. MATERIALS AND METHODS: One hundred and twenty-eight patients undergoing peripheral and renal angioplasty using a sheath size of up to 6 French were recruited prospectively. The mobilization protocol consisted of supine bed rest for 2 h, followed by gradual mobilization, so that the patient was ambulant 4 h after the procedure. Mobilization was delayed if clinically appropriate. Puncture sites were scored for discomfort, paraesthesia, visible bruising and palpable haematoma after groin compression and the following morning. RESULTS: One hundred and forty-four puncture sites were studied. There were 44 haematomas in total, of which 37 (26%) were less than 2.5 cm and seven (4.9%) were between 2.5 cm and 7.5 cm. Four patients (2.8%) had visible bruising greater than 7.5 cm. No patient assessed discomfort higher than moderate at any stage. Mobilization was delayed in 15 patients. In 11 this was due to puncture site oozing, haematoma in one, two were hypertensive and one required surgery for limb ischaemia. All complications occurred within 4 h of angioplasty. No patient required surgery or transfusion for haemorrhagic complications. CONCLUSION: Mobilization at 4 h was successful in 90% of cases but 10% require more prolonged bed rest. No delayed complications occurred. These results suggest that day case angioplasty is feasible in most cases.Butterfield, J. S. (2000). Clinical Radiology55, 874-877

Adult↗
PubMed2000

Radiation risk estimation in varicocele embolization.

Varicocele embolization is performed in healthy young men with normal life expectancy. Therefore, it is essential that the radiation risks associated with the procedure are minimized. The radiation risks associated with varicocele embolization have been estimated retrospectively from dose-area product records in a series of 41 cases and compared with a prospective series of 10 cases. Lithium fluoride dosemeters were used to measure gonad dose in the prospective series. Estimated lifetime fatal cancer risk was of the order of 0.1% in the retrospective series. A seven-fold reduction in median radiation dose was observed in the prospective series. The results indicate that with meticulous attention to technique, substantial reductions in radiation exposure can be achieved.

Adult↗
PubMed1999

Management of acute nontraumatic upper limb ischemia.

A retrospective review of all patients presenting to a tertiary referral center with acute nontraumatic upper limb ischemia between January 1992 and June 1997 was undertaken to examine the role of intraarterial thrombolysis in the management of such cases. Twenty-one patients were identified in the radiology and vascular surgery departments' registers. Twenty (95%) underwent angiography, demonstrating subclavian artery occlusion in four, axillary in two, brachial in 13, and one at the digital level. Intraarterial thrombolysis was attempted in 12 patients. There were three technical failures, all requiring embolectomy. Six had complete lysis and resolution of their symptoms. One patient had partial lysis but experienced no further rest pain. Thrombolysis was unsuccessful in two cases with one subsequently requiring embolectomy and the other surgical bypass. Three patients had surgical intervention as their primary procedure with two favorable outcomes and one ending in above-elbow amputation. Five patients were treated conservatively with heparin, resulting in three partial and two full recoveries. One patient experienced complete resolution of symptoms with an intravenous prostacyclin infusion. Both electrocardiograms (ECG) and echocardiograms (ECHO) were of limited diagnostic aid, and long-term warfarin anticoagulation was prescribed to all patients. There was no recurrence of upper limb ischemia at a median follow up of 18 months. Intraarterial thrombolysis is an effective first line treatment for acute nontraumatic upper limb ischemia in selected cases.

Acute Disease↗
PubMed1999

Comparison of iodixanol and iohexol in renal impairment.

Iodixanol (Visipaque, Nycomed, Oslo, Norway) is an iodinated contrast medium in the form of a non-ionic dimer which is iso-osmolar with plasma at all iodine concentrations. There is little evidence regarding its renal tolerance in renal impairment. We therefore undertook a prospective randomized comparison of iodixanol and the non-ionic monomer iohexol (Omnipaque, Nycomed, Oslo, Norway). The serum creatinine was measured pre- and post-angiography in a series of in-patients to establish whether there was any clinically detectable evidence of superiority of iodixanol over iohexol in this high risk group. 8/54 (15%) patients in the iodixanol group had a rise in creatinine of > 10% in the week following angiography compared with 15/48 (31%) in the iohexol group (p < 0.05). The creatinine rise was positively correlated with the dose of both contrast media. These results suggest that iodixanol may be slightly less nephrotoxic than iohexol.

Aged↗
PubMed1998

Supradiaphragmatic middle aorta syndrome--MR and angiographic imaging.

We describe the case of an asymptomatic 24-year-old man with hypertension who was investigated for aortic coarctation but found on MR scanning to have narrowing of the distal thoracic aorta. Stenosis of the thoracolumbar aorta--the Middle Aorta Syndrome--is rare and is usually found below the diaphragm. The MRI and angiographic findings are presented.

Adult↗
PubMed1998

Outpatient angiography: a prospective study of 3 French catheters in unselected patients.

Financial constraints and bed shortages led to a re-evaluation of the policy of routine hospital admission for angiography. All patients referred for peripheral and renal angiography over an 8 month period had the procedure performed as an outpatient with a 3 F catheter. Patients were kept supine for 1 h and discharged 2 h after the angiogram. No significant complications resulted from the early mobilization of 219 patients who had outpatient 3 F angiography. It was a safe, well tolerated procedure, resulting in images of consistently adequate quality.

Adolescent↗
PubMed1998

The use of TIPS to control bleeding caput medusae.

Two patients with cirrhosis and portal hypertension had persistent bleeding from caput medusae and ascites. Transjugular intrahepatic portosystemic shunt (TIPS) resulted in regression of the caput medusae and ascites in both cases.

Aged↗