The economic dimensions of integrating flood management and agri-environment through washland creation: a case from Somerset, England.

In many river floodplains in the UK, there has been a long history of flood defence, land reclamation and water regime management for farming. In recent years, however, changing European and national policies with respect to farming, environment and flood management are encouraging a re-appraisal of land use in rural areas. In particular, there is scope to develop, through the use of appropriate promotional mechanisms, washland areas, which will simultaneously accommodate winter inundation, support extensive farming methods, deliver environmental benefits, and do this in a way which can underpin the rural economy. This paper explores the likely economic impacts of the development of flood storage and washland creation. In doing so, consideration is given to feasibility of this type of development, the environmental implications for a variety of habitats and species, and the financial and institutional mechanisms required to achieve implementation.

Treatment of dirty water from dairy farms using a soil-based batch recirculation system.

"Dirty water", a wastewater produced on dairy farms, is typically disposed of by application to land with no prior treatment. Pollution can occur if the dirty water reaches a watercourse following an inadequate period of retention in the soil. This paper describes experiments using a novel, soil-based batch recirculation system for pre-treating dirty water prior to land application. Three polythene-lined, vegetated soil-based treatment planes (23 m long, 1 m wide, 0.25 m deep) were constructed. Each treatment plane was supplied with approximately 1 m3 of dirty water which was recirculated until a clear treatment pattern had emerged. Five batches were treated over a six-month period. The soil-based treatment system could typically be expected to achieve a 90% removal of key pollutants in approximately two weeks for BODs and NH4-N, and three weeks for MRP and total solids. An exponential trendline gave a good fit to the treatment curves for BOD5, NH4-N and MRP after the first day or two of batch treatment. The data for total solids removal were more variable. Treatment rates were sustained throughout the five runs for BOD5 and NH4-N, indicating no apparent effect of seasonal weather on the treatment process. The apparent progressive slowing of the MRP removal rate throughout the treatment of the five batches may have implications for the sustainable use of this technology for phosphorus control.

Removal of ammoniacal nitrogen from landfill leachate by irrigation onto vegetated treatment planes.

Leachate is a contaminated liquor resulting from the disposal of solid and liquid wastes at landfill sites that must be treated before discharge. Vegetated leachate treatment planes have been used at landfill sites in the UK but have received little scientific attention. This paper describes studies of model leachate treatment planes with a focus on the removal of ammoniacal nitrogen (NH3-N). Small-scale and field-scale experimental treatment planes were constructed. filled with clay loam soil and vegetated with grass (Agrostis stolonifera). Landfill leachate was applied at hydraulic loading rates ranging from 17-217l/m2/d. An exponential relationship was used to characterise the pattern of NH3-N removal. No relationship was observed between the hydraulic loading rate and the NH3-N removal rate constants (R2 = 0.0039). The daily specific NH3-N mass removal rate was found to be linearly related to the NH3-N concentration at the start of that day of treatment (R2 = 0.35). Possible causes of variation in the rate of NH3-N removal between experiments are discussed. A simple inorganic nitrogen balance indicated that the mass of N-H3-N and NO2-N removed was not accounted for by NO3-N production. Explanations for this apparent nitrogen deficit are discussed.

Outcome after major renovascular injuries: a Western trauma association multicenter report.

BACKGROUND: Major renal vascular injuries are uncommon and are frequently associated with a poor outcome. In addition to renal dysfunction, posttraumatic renovascular hypertension may result, although the true incidence of this complication is unknown. The objective of this study was to describe the factors contributing to outcome after major renovascular trauma. We hypothesized that the highest percentage of renal salvage would be achieved by minimizing the time from injury to repair. METHODS: This was a retrospective chart review over a 16-year period conducted at six university trauma centers of patients with American Association for the Surgery of Trauma grade IV/V renal injuries surviving longer than 24 hours. Postinjury renal function with poor outcome was defined as renal failure requiring dialysis, serum creatinine greater than or equal to 2 mg/dL, renal scan showing less than 25% function of the injured kidney, postinjury hypertension requiring treatment, or delayed nephrectomy. Data collected for analysis included demographics, mechanism of injury, presence of shock, presence of hematuria, associated injuries, type of renal injury (major artery, renal vein, segmental artery), type of repair (primary vascular repair, revascularization, observation, nephrectomy), time from injury to definitive renal surgery, and type of surgeon performing the operation (urologist, vascular surgeon, trauma surgeon). RESULTS: Eighty-nine patients met inclusion criteria; 49% were injured from blunt mechanisms. Patients with blunt injuries were 2.29 times more likely to have a poor outcome compared with those with penetrating injuries. Similarly, the odds ratio of having a poor outcome with a grade V injury (n = 32) versus grade IV (n = 57) was 2.2 (p = 0.085). Arterial repairs had significantly worse outcomes than vein repairs (p = 0.005). Neither the time to definitive surgery nor the operating surgeon's specialty significantly affected outcome. Ten percent (nine patients) developed hypertension or renal failure postoperatively: three had immediate nephrectomies, four had arterial repairs with one intraoperative failure requiring nephrectomy, and two were observed. Of the 20 good outcomes for grade V injuries, 15 had immediate nephrectomy, 1 had a renal artery repair, 1 had a bypass graft, 1 underwent a partial nephrectomy, and 2 were observed. CONCLUSION: Factors associated with a poor outcome following renovascular injuries include blunt trauma, the presence of a grade V injury, and an attempted arterial repair. Patients with blunt major vascular injuries (grade V) are likely to have associated major parenchymal disruption, which contributes to the poor function of the revascularized kidney. These patients may be best served by immediate nephrectomy, provided that there is a functioning contralateral kidney.

The feasibility and accuracy of the sentinel lymph node biopsy for breast carcinoma.

As the procedure of sentinel lymph node biopsy for breast cancer becomes more widely available, the practicality of it in the hands of general surgeons should be assessed. This is a study of the accuracy and use of this procedure. A prospective study was conducted at two university-affiliated teaching hospitals. Ninety-one patients with invasive breast cancer were enrolled in the study. Twelve patients were excluded from analysis. The remaining 79 patients were injected peritumorally with technetium-99m-labeled sulfur colloid and isosulfan vital blue dye. The sentinel lymph node was located and excised using a gamma probe, and the definitive breast cancer operation was completed, including an axillary dissection. Histology of the sentinel lymph node specimen was compared with that of the axilla. Sentinel lymph nodes were located in 64 (81.0%) of the 79 patients. Sentinel lymph nodes and axillary nodes were benign in 44 (68.8%) of the 64 patients; these patients could potentially have been spared the axillary dissection. Fourteen (21.9%) patients had metastatic cancer to the sentinel nodes only, and five (7.8%) patients had axillary metastasis beyond the sentinel lymph node. Among the 64 patients, there was one false negative. Sensitivity and specificity when a sentinel lymph node was found were 95.0 per cent and 100 per cent, respectively. The sentinel lymph node accurately predicted the axillary contents 98.4 per cent of the time. This study demonstrates that the sentinel lymph node can be identified and is reliable in predicting axillary node status. This study also shows that the procedure has a notable learning curve, but can be used by general surgeons with a commitment to the care of breast cancer patients.

A comparison of sonographic examinations for trauma performed by surgeons and radiologists.

BACKGROUND: It has been demonstrated that surgeons and surgery residents, trained in the focused abdominal sonographic examination, are able to accurately and reliably evaluate trauma patients. Despite this, radiologists have objected to surgeon-performed sonography for several reasons. We set out to compare the accuracy of sonographic examinations performed by surgery residents and radiologists. METHODS: A retrospective review of medical records of all trauma patients who received focused ultrasound examinations from January 1, 1995, through June 30, 1996, at one of two American College of Surgeons-verified Level I trauma centers in the same city was undertaken. Ultrasound examinations were performed by surgery residents at trauma center A (TCA) and by radiologists or radiology residents at trauma center B (TCB). Findings for each patient were compared with the results of computed tomography, diagnostic peritoneal lavage, operative exploration, or observation. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated for each group of patients. Comparison of patient charges for the trauma ultrasound examinations at each of the trauma centers was also made. RESULTS: Patient populations at the two centers were similar except that the mean Injury Severity Score at TCB was higher than at TCA (11.74 vs. 9.6). Sensitivity, specificity, accuracy, or negative predictive value were not significantly different between the two cohorts. A significantly lower positive predictive value for examinations performed by surgery residents was noted and attributed to a lower threshold of the surgery residents to confirm their findings by computed tomography. Billing data revealed that the average charge for trauma sonography by radiologists (TCB) was $406.30. At TCA, trauma sonography did not generate a specific charge; however, a $20.00 sum was added to the trauma activation fee to cover ultrasound machine maintenance and supplies. CONCLUSION: Focused ultrasound examination in the trauma suite can be as safely and accurately performed by surgery residents as by radiologists and radiology residents and should be a routine part of the initial trauma evaluation process.

Big cat attack: a case study.

A 28-year-old man was attacked by a large female tiger at an exotic animal farm, sustaining penetrating injuries to the neck and pharynx as well as a cervical spine fracture. This case and review of the literature demonstrates the ability of these animals to cause significant trauma and occult injuries. Furthermore, this case demonstrates the need for a high index of suspicion when treating these patients, as serious underlying bony and soft tissue damage can easily be overlooked.

PASG: does it help in the management of traumatic shock?

A prospective, randomized study was designed to determine the efficacy of pneumatic antishock garment (PASG) in the treatment of traumatic shock in a medium-size urban community. A total of 291 traumatic shock patients were assigned to either the PASG or No-PASG treatment groups. Of these, data from 248 patients were analyzed in detail. Analysis of demographic factors--such as age, sex, and mechanism of injury--as well as prehospital evaluative tools--such as trauma and CRAMS scores, and injury severity scores--revealed that the two groups were well-matched. This study did not demonstrate significant differences in hospital stay or mortality between PASG and No-PASG patients. Similarly, in the subset of patients with blunt trauma, PASG was not found to be beneficial.

Duplex ultrasonography criteria for internal carotid stenosis of more than 70% diameter: angiographic correlation and receiver operating characteristic curve analysis.

OBJECTIVE: To determine duplex ultrasonography criteria for detecting stenosis of 70% or more in the internal carotid artery, to be used as a means of selecting candidates suitable for endarterectomy (a procedure suggested by the North American Symptomatic Carotid Endarterectomy Trial as appropriate for symptomatic patients with 70% to 99% stenosis). PATIENTS AND METHODS: Between Jan. 1, 1991, and Apr. 30, 1993, 120 patients underwent internal carotid angiography at a tertiary care hospital for transient ischemic attacks, asymptomatic bruits or preoperative assessment. Of these, 83 also underwent duplex ultrasonography within 31 days of angiography. The angiographic and sonographic studies for 145 vessels in 75 of the patients (50 men and 25 women) were suitable for further study. The sonographic criteria were selected on the basis of a receiver operating characteristic curve relating peak systolic velocity of the internal carotid artery to the degree of stenosis determined angiographically. RESULTS: Angiography indicated that 33 of the vessels had stenosis of 70% or more and that 12 additional vessels were completely occluded. The combined sonographic criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more yielded 91% sensitivity and 60% specificity for angiographically determined stenosis of 70% or more. CONCLUSION: In this patient population the combined criteria of peak systolic velocity of less than 40 cm/s or 175 cm/s or more were highly sensitive and reasonably specific for internal carotid artery stenosis of 70% or more.

The questionable utility of mandatory screening for the human immunodeficiency virus.

Trauma patients have been identified as a high-risk group for human immunodeficiency virus (HIV) infection, particularly those patients with penetrating injuries from urban violence. We prospectively evaluated more than 2,000 trauma patients for HIV infection at our ACS-certified trauma center and report the results. Between September 1987 and December 1991, 2,004 patients were admitted to our trauma unit. All patients underwent HIV antibody assay by protocol. Three patients had positive test results, and all were confirmed as true positives. Two patients were known at the time of their trauma to be HIV positive, and the third had engaged in high-risk behavior. No health care worker reported inoculation with or mucosal exposure to HIV from any of these patients. In our trauma unit, the prevalence of HIV infection was only 0.15%. More than $74,000 was spent on screening without demonstrable benefit to the patients or increased protection for the trauma team. Routine testing of patients for HIV can be justified to establish epidemiologic parameters and in the case of high-risk groups, but it is not cost-effective in low-risk groups. Persistent testing of populations at low risk is a futile expenditure of precious health care dollars and is of questionable utility.

Thrombolysis for occluded vein bypass grafts through surgical access.

PURPOSE: This report describes surgical access to occluded vein grafts for thrombolysis by direct cutdown where indirect angiographic techniques have failed. METHOD: A sheath is introduced directly into the proximal vein graft. Distal thrombus is lysed following standard protocol. The residual thrombus at the origin of the graft is removed surgically, and the area is closed with a patch angioplasty. RESULTS: Distal thrombus was completely lysed in two vein grafts without bleeding complications. CONCLUSION: The thrombus "cork" that forms at the upper end of an occluded vein graft may deflect the angiographer's guide wire, but the distal thrombus usually remains soft and amenable to lysis. Angiographic access should not be a limiting factor in thrombolysis of an occluded vein graft.

The contribution of needle size and other factors to headache following myelography.

The author performed a randomized prospective study of the effects of needle size and of age, sex, myelogram type and operators on the incidence of headache following myelography. In 113 patients randomized to 22 G and 25 G needle groups, data were obtained by questionnaire on the frequency of headache up to five days following the procedure. The influence of needle size was statistically insignificant (63%, 48%, p > 0.05). Age (p = 0.0002), sex (p = 0.01), myelogram type (p = 0.002) and myelographer (p = 0.03) significantly affected the frequency of headache. The size of the dural perforation appears to be less important than factors relating to age, sex, myelogram type and individual myelographers in the development of headache after myelography.

Laparoscopic cholecystectomy during pregnancy in symptomatic patients.

BACKGROUND: The management of symptomatic biliary tract disease during pregnancy is controversial. Although most patients receive temporizing medical therapy, some authors have advocated a more aggressive surgical approach. We have extended this surgical approach to include laparoscopic cholecystectomy. METHODS: Five women with pregnancies at 13 to 23 weeks' estimated gestational age underwent laparoscopic cholecystectomy for symptomatic cholelithiasis or acute cholecystitis between March and September 1991. RESULTS: No complications occurred, and the postoperative courses of all patients were unremarkable. Four patients have been delivered of healthy babies, and the fifth patient is still pregnant at the time of this report. CONCLUSIONS: Laparoscopic cholecystectomy appears to be a safe treatment for selected patients with symptomatic biliary tract disease during pregnancy. Further study is warranted to determine its proper role in managing this difficult clinical problem.

Atherectomy. Early use of three different methods.

The authors report their initial experience in 52 patients with three different techniques of peripheral artery atherectomy--the Tracwright (Kensey), used in 19 patients, the Simpson AtheroCath, used in 19 patients and the transluminal extraction catheter, used in 14 patients. The indications for atherectomy were claudication in 42 (80%) and limb-threatening ischemia in 10 (19%). There were no deaths. Complications included three arterial perforations, one thrombosis and one groin hematoma requiring operative evacuation. There were no distal embolizations. Atherectomy was initially unsuccessful in 15 (29%) patients. For the successfully completed procedures, the 1-year primary patency rates were as follows: Tracwright (Kensey) catheter 56%, Simpson catheter (63%) and transluminal extraction catheter (0%). Use of subsequent nonoperative procedures on recurrent stenoses produced secondary patency rates of 77% for the Tracwright (Kensey) technique, 80% for the Simpson catheter technique and 78% for the transluminal extraction catheter technique. The authors conclude that their early results justify further evaluation of these three techniques. Use of the transluminal extraction catheter is associated with higher rates of occlusion and restenosis.

Systemic blood flow to the lung after bronchial artery occlusion in anesthetized sheep.

To compare the effectiveness of different embolizing agents in reducing or redistributing bronchial arterial blood flow, we measured systemic blood flow to the right lung and trachea in anesthetized sheep by use of the radioactive microsphere method before and 1 h after occlusion of the bronchoesophageal artery (BEA) as follows: injection of 4 ml ethanol (ETOH) into BEA (group 1, n = 5), injection of approximately 0.5 g polyvinyl alcohol particles (PVA) into BEA (group 2, n = 5), or ligation of BEA (group 3, n = 5). After occlusion, angiography showed complete obstruction of the bronchial vessels. There were no changes in tracheal blood flow in any of the groups. Injection of ETOH produced a 75 +/- 14% (SD) reduction in flow to the middle lobe (P less than 0.02) and a 75 +/- 13% reduction to the caudal lobe (P less than 0.01), whereas injection of PVA produced a smaller reduction in flow to these two lobes (41 +/- 66 and 51 +/- 54%, respectively). After BEA ligation there was a 52 +/- 29% reduction in flow to the middle lobe and a 53 +/- 38% reduction to the caudal lobe (P less than 0.05). This study has significant implications both clinically and experimentally; it illustrates the importance of airway collateral circulation, in that apparently complete radiological obstruction of the BEA does not necessarily mean complete obstruction of systemic blood flow. We also conclude that, in experimental studies in which the role of the bronchial circulation in airway pathophysiology is examined, ETOH is the agent of choice.

Total occlusion of the common carotid artery with patent internal carotid artery. Identification with color flow Doppler imaging.

With common carotid artery occlusion there is usually no flow in the distal vessels. However, flow to the ipsilateral internal common carotid artery may be maintained by collateral vessels. Nine of 1100 patients referred for carotid duplex sonography were found to have occluded common carotid arteries. Five of these patients had collateral circulation with reconstitution of flow via the external carotid artery. The color Doppler sonograms of three representative patients are presented. There was antegrade flow in the internal carotid artery with retrograde flow in the external carotid artery.

Hyperperfusion syndrome after carotid endarterectomy. CT changes.

This article describes the CT scans of two patients who, following carotid endarterectomy, developed headache and seizures suggestive of hyperperfusion syndrome. Their CT scans demonstrated ipsilateral mass effect and white matter hypodensity. One patient progressed to hemorrhage and died. Although infarction is described as the commonest neurologic event to occur after carotid endarterectomy, autopsy or cerebral blood flow studies in these patients suggests that the changes were due to hyperperfusion rather that infarction.

Embolization of a catheter-related hepatic artery pseudoaneurysm after long-term biliary drainage.

Hemobilia is a frequent complication of percutaneous transhepatic biliary drainage, occurring most commonly at the time of initial catheter placement. The authors report on the angiographic diagnosis and embolization of a pseudoaneurysm of the right hepatic artery in a patient with hemobilia. This occurred after 2.5 years of catheter drainage for biliary obstruction due to malignant disease. Bleeding as a complication of biliary drainage can be the result of inadvertent placement of catheter side holes in the hepatic parenchyma, iatrogenic arterioportal and arteriohepatic venous shunts and pseudoaneurysms. This case report illustrates that hemobilia, even with long-term percutaneous transhepatic biliary drainage, may be associated with a radiologically treatable, drainage-related vascular abnormality rather than simply diffuse hemorrhage from a friable tumor.