Medullary metastasis causing impairment of respiratory pressure output with intact respiratory rhythm

BACKGROUND: Vascular access failure is an important cause of morbidity in end-stage renal failure patients on hemodialysis. Currently, little is known about risk factors that predispose certain hemodialysis patients to recurrent access thrombosis. Hyperhomocysteinemia (common in patients with renal failure) predisposes people with normal renal function to recurrent and early-onset venous thrombosis, although the effect on vascular access thrombosis is currently unknown. Previous studies have suggested that high titers of IgG anticardiolipin antibody (IgG-ACA) predispose hemodialysis patients to access thrombosis. This cross sectional study was designed to assess for an association between two predictive variables, hyperhomocysteinemia and elevated titers of IgG-ACA, and vascular access thrombosis in patients undergoing chronic hemodialysis. METHODS: Risk factors for vascular access thrombosis were documented, and the number of episodes of access thrombosis was recorded for the previous three years in patients undergoing hemodialysis. Midweek predialysis total homocysteine and IgG-ACA levels were measured in all subjects. RESULTS: Of the 118 patients who were enrolled, 75.4% had a native arteriovenous fistula. Episodes of vascular access thrombosis were recorded for the previous three years; 34 (28.8%, 95% CI 20.9 to 37.9%) patients had 72 episodes of access thrombosis over the period of risk. Mean homocysteine levels were not significantly different between these 34 patients (28.6 micromol/liter, 95% CI 24.5 to 32.7) and the patients who had no episodes of graft thrombosis (29.8 micromol/liter, 95% CI 26.7 to 32.9). Sixty-seven unselected patients had IgG-ACA levels drawn for analysis, and all assays were negative. The only variable that was associated with a higher risk for graft thrombosis was the type of vascular access placed (odds ratio 4.0, 95% CI 1.6 to 9.6 for patients with a synthetic graft compared with those with an arteriovenous fistula). CONCLUSIONS: No association was found between homocysteine levels or anticardiolipin antibody and vascular access thrombosis in our patient population.     

Use of expanded polytetrafluoroethylene grafts for vascular access in hemodialysis: laboratory and clinical evaluation

Vascular access for chronic hemodialysis has evolved considerably over the past 10 years with development of vascular substitutes. The bovine heterograft is the choice of most dialysis centers when a subcutaneous conduit is needed in lieu of an in situ arteriovenous fistula. Bovine grafts have solved some problems, but further improvement in blood access prostheses is needed. Polytetrafluoroethylene (PTFE) grafts were evaluated in a laboratory and clinical study. In animals, PTFE proved to be satisfactory for fistula construction based on patency, incorporation into tissue, and ease of puncture. Ten patients underwent 11 vascular access procedures using PTFE grafts as a conduit. There were no technical operative complications. One graft was occluded by extravasation during dialysis and flow could not be restored. Otherwise, all grafts are patent 9 to 18 months postoperatively. Grafts of 8.0 mm in diameter have not given desirable flow rates, whereas 6.0 mm grafts have. Prolonged bleeding from puncture has been a problem in some cases. Otherwise, PTFE appears to be a satisfactory conduit for hemodialysis vascular access.     

Effects of hand dominance and sleep side preference on hemodialysis vascular access survival

We examined the effects of hand dominance and the patients' stated preference of the sleeping position on the survival of vascular accesses for hemodialysis in different locations. Analysis was made of vascular access survival times after 1, 126 vascular access surgeries performed between January 1, 1989, and December 31, 1994. We found that hand dominance and access site were not related to any survival differences in patients with autogenous fistulas, but thigh grafts on both sides had greater survival than arm grafts. The preferential side for sleeping similarly did not seem to affect access survival, but patients who stated a sleep preference on the side opposite their vascular graft tended to have longer access survival time.     

Arteriovenous fistula. Vascular access for long-term hemodialysis

Long-term hemodialysis remains the most important support for patients with ESRD, and reliable vascular access is an essential component of this management plan. Recent refinements in AV fistula surgical techniques have produced this dependable, well-tolerated, long-term access route for hemodialysis.     

Care of the hemodialysis patient with a new permanent vascular access: review of assessment and teaching

Problems related to vascular access are the main reasons for admission to hospitals for hemodialysis patients today. Some patients develop vascular access problems prior to use and many require repeated surgery. This article addresses some of the key aspects of patient assessment and monitoring in the immediate preoperative/postoperative period. The focus is on the prevention of early vascular access failure. Approaches for patient teaching are included, as are strategies that should be part of a vascular access management program.     

Rotationplasty of the lower limb for childhood osteosarcoma of the femur

OBJECTIVE: To describe investigations into an increase in hemodialysis-related bacteremia that occurred in our hospital in the first 6 months of 1996. SETTING: Hemodialysis unit in a tertiary-care medical center. METHODS: Prospective surveillance for hemodialysis bacteremia has been performed for several years. Cases that occurred in 1995 were compared to cases in the first 6 months of 1996. Unit data on dialysis runs and method of dialysis access were used to calculate rates. Nested polymerase chain reaction (PCR) was used to type 18 Staphylococcus aureus isolates from 1996. A case-control study comparing 80 randomly selected hemodialysis patients from 1995 and 1996 was performed to examine infection risk factors. RESULTS: The hemodialysis bacteremia rate was 1.2 per 1,000 runs in 1995 and 2.8 per 1,000 in the first 6 months of 1996 (P=.0009). The 25 cases in 1995 and 32 in the first half of 1996 were similar in age, gender, means of vascular access, and microbial etiology. Central venous catheter (CVC) access accounted for >90% of cases in both time periods. S aureus was the most common microbial etiology (53% of the 1996 cases). PCR typing of S aureus isolates from 1996 demonstrated five different strains, the most common having six isolates. The use of CVCs as a means of vascular access abruptly increased in the unit in January 1996, from <30% of dialysis runs in 1995 to >40% in 1996 (P<.001), associated with structural changes in healthcare delivery in the region resulting in delays in performing surgical procedures, such as creation of vascular grafts and fistulae. CONCLUSION: A marked increase in hemodialysis bacteremia occurred in 1996, associated with increased reliance on CVCs for vascular access in hemodialysis patients during a period of healthcare restructuring.     

Assessing medical care of dying residents in nursing homes

A rational approach to hemodialysis access in the patient with renal failure requires an understanding of many factors. The initial approach to such patients and subsequent decisions have a significant impact on quality of life as well as the morbidity of access choices. Autogenous vascular access remains the gold standard in the care of these patients. Alternatives are less desirable but are necessary in an increasing number of situations. Careful thought before embarking on a procedure will provide better long-term function and preserve the patient's options for the future.     

Cholecystokinergic innervation of nucleus accumbens subregions

There is evidence that high frequency, as well as long duration, hemodialysis provides better clinical outcomes. We developed nocturnal hemodialysis, a new innovative form of renal replacement therapy, which is performed six to seven nights per week for 8 to 10 h during sleep at home. Blood flow was set at 300 ml/min and dialysate flow at 100 ml/min. An internal jugular catheter was used as the vascular access. Special precautions were taken to prevent accidental disconnection during sleep, as well as air embolization. Dialysis functions from the patient's home were monitored continuously via a modem at the nocturnal hemodialysis center. Twelve patients have completed training and have been successfully performing nocturnal hemodialysis for up to 34 mo. This study represents 170 patient months of experience accumulated over 3 yr. There was hemodynamic stability and significant subjective improvement in patient well being. Nightly Kt/V was 0.99. Weekly removal of phosphate was twice as high and beta2 microglobulin 4 times as high as conventional hemodialysis. All patients have discontinued their phosphate binders and have increased dietary phosphate and protein intake. BP control was achieved with fewer medications. Dialyzer reuse has decreased the operating costs to the level of the other form of home dialysis. Complications were infrequent and were related primarily to the dialysis access. Nocturnal hemodialysis represents the most efficient form of dialysis at low cost and should be considered as an option for patients who can be trained for home hemodialysis.     

Perivalvular abscess complicating infective endocarditis: complementary role of echocardiography and indium-111-labeled leukocytes

A 49-year-old black man with hypertension-induced chronic renal failure requiring hemodialysis and a history of arteriovenous access graft infection was admitted with Staphylococcus aureus sepsis, dyspnea, and peri-incisional erythema over his arteriovenous graft fistula. Results of a transthoracic echo demonstrated aortic sclerosis and concentric left ventricular hypertrophy. Results of a whole-body In-111 white cell (WBC) scan were negative over the arteriovenous graft site; however, an intense abnormal focus of labeled WBCs was evident to the left of the sternum. A subsequent transesophageal echocardiogram showed a mixed cystic-solid calcified mass adjacent the left aortic cusp. Surgery confirmed a perivalvular abscess. As a whole-body imaging modality, the In-111 WBC scintigram indicated the true location of the infectious process responsible for the patient's sepsis. The combination of echocardiography and radiolabeled WBC imaging increases sensitivity for detection of endocarditis/perivalvular abscess. Radiolabeled WBC imaging is more efficacious for monitoring therapy because the echocardiogram often does not change with treatment of endocarditis/perivalvular abscess.     

Venous rupture complicating hemodialysis access angioplasty: percutaneous treatment and outcomes in seven patients

OBJECTIVE: To evaluate percutaneous treatment options for preserving hemodialysis access after angioplasty-related venous rupture, we retrospectively reviewed the charts for all dialysis access angioplasties performed over a 33-month period. Seven cases of venous rupture after venous angioplasty were identified (four men and three women; mean age, 63.5 years). Treatment included observation only (n = 1), a second prolonged balloon inflation at the rupture site (n = 2), stent insertion (n = 5), and manual graft occlusion (n = 1). Treatment was successful in eliminating contrast extravasation in all patients while maintaining immediate graft function in six out of seven patients. None of the patients required emergent surgical intervention. The mean primary and secondary patency rates of the salvaged grafts after intervention were 2.3 and 9.3 months, respectively. Five of seven access sites were still patent at the most recent follow-up. CONCLUSION: Prolonged balloon inflation or placement of a stent may salvage hemodialysis access in most patients after angioplasty-related venous rupture. Primary and secondary patency have proven to be satisfactory.     

Purification and properties of an amylopullulanase, a glucoamylase, and an alpha-glucosidase in the amylolytic enzyme system of Thermoanaerobacterium thermosaccharolyticum

Impairment of hemodialysis (HD) vascular access, remains a frustrating problem for both the patient who possesses an arteriovenous graft (AVG) and the nephrologist who cares for the patient. We instituted a vascular access surveillance protocol intended to detect and correct evolving stenosis in patients with AVGs. The principal screen was the observation of dynamic venous pressure (VP) at a blood flow rate of 200 mL/min during the first 5 minutes of each HD session. If VP at a blood flow rate of 200 mL/min was 140 mm Hg or greater in three of six consecutive readings, recirculation greater than 15% on two observations, graft-arm swelling observed, or prolonged bleeding postdialysis observed, then the patient was referred for angiography and then angioplasty or surgery if a vascular stenosis of greater than 50% was documented. Sixty-four patients with a synthetic AVG comprised the study group. Seventy-two episodes of AVG impairment (56 with stenosis > or = 50% on angiography, 16 with thrombosis) occurred in these patients during the study period. In 63 of 72 impairment episodes, the preceding vascular access screening test was positive. The calculated sensitivity and specificity of the vascular access protocol was 88% and 81%, respectively. Calculation of the sensitivity and specificity for the VP alone was 81% and 85%, respectively. Comparison of the study group with a similar historical control group (55 patients) showed a significantly lower thrombosis rate (P = 0.03; 95% confidence interval [CI], 0.025 to 0.375) in the study group (0.29 thrombotic episodes/graft-year at risk) versus the historical control group (0.49 thrombotic episodes/graft-year at risk). In summary, a vascular access surveillance protocol is a useful tool to predict patients at risk for AVG venous stenosis and/or thrombosis. A dynamic VP of 140 mm Hg or greater appears to be the optimal threshold pressure. A decrease in synthetic AVG thrombosis rate resulted from the use of this surveillance protocol.     

Correlates of vascular access and nonvascular access-related hospitalizations in hemodialysis patients

Four hundred and thirty randomly selected hemodialysis patients, aged 20 years and over, were studied to identify risk factors for vascular access and nonvascular access-related hospitalizations in the immediately preceding 1 year. Risk estimates for hospitalization were assessed using a multinominal logistic analysis model. We measured functional status, utilizing a 14-point Karnofsky scale, and in a separate analysis of covariance, in which Karnofsky score was the outcome, we examined the relationships of age, gender, ethnicity, renal diagnosis, and hospitalization. Individual comparisons were adjusted for multiple comparison bias by Tukey's Honest Difference method. There were a total of 508 hospitalizations of which 322 (63%) lasted > or = 1 week. Two hundred and sixty (60%) patients were hospitalized at least once; 105 (24.4%) for access problems only, 115 (27%) for a nonaccess problem only, and 40 for access and nonaccess-related problems. Access-related problems, accounted for 48% of all hospitalizations. The risk of hemodialysis vascular access morbidity was increased in women (p < 0.028) and white (p < 0.048) hemodialysis patients. Neither diabetic nor elderly hemodialysis patients were at greater risk for access hospitalization than their respective counterparts, though a greater proportion of the access hospitalizations in the elderly (> or = 64 years) lasted > or = 1 week (p < 0.0006). More access-related hospitalizations in blacks (64.5%), lasted for > or = 1 week than in whites (40.6%) (p < 0.001). Hispanics (p < 0.043), whites (p < 0.002), and the older patients (p < 0.054) were at greater risk for nonaccess hospitalization than blacks and younger patients, respectively. Even after adjusting for age, race, and diabetes, each decrease of one unit in the modified Karnofsky score was associated with a 3-4% increased risk for all types of hospitalization (p < 0.001)--poor functional status is associated with increased risk for all hospitalizations. We conclude that the risk for hemodialysis vascular access morbidity is increased in women and white hemodialysis patients. Poor functional status is associated with increased risk for all hospitalizations.     

Carbon monoxide poisoning in a pig-breeding unit due to wrongly adjusted propane gas infrared radiatro

17 patients are reported in whom an arterio-venous shunt has been established by means of an arterial graft (bovine origin). The indications were: need of maintenance hemodialysis under absence of functioning shunt and lack of peripheral vessels suitable for construction of a Cimino fistula. 14 shunts developed function without any complication. In 2 patients thrombosis of the graft occured. Both of them could be re-established in function by thrombectomy. 2 cases necessitated removal of the transplant. The question as to an immunological rejection remains open up to now. The advantages of the new shunt are: immediate readiness for hemodialysis, sufficiently long distance for puncture, easy and painless punctures and the possibility of access to deeper vessels.     

Frequency dependent force generation correlates with sarcoplasmic calcium ATPase activity in human myocardium

The purpose of this study was to implement and evaluate a clinical protocol for following longitudinally the luminal responses of microvessel cell seeded expanded polytetrafluoroethylene (ePTFE) vascular grafts implanted for hemodialysis access. Half of the patients enrolled in the study were randomized to receive grafts that were "seeded" with transplanted microvessel cells derived from autologous subcutaneous fat; the other half of the patients received nonseeded grafts. The patients agreed to scheduled biopsies of their grafts at three postoperative times. All biopsy samples were evaluated by routine histologic and electron microscopy techniques. Three men and six women were enrolled in the study. All operative procedures were tolerated well. However, only two of the nine patients agreed to 1-year postimplantation biopsies; one of these patients had been randomized to receive a "nonseeded" ePTFE graft and one randomized to receive a "seeded" graft. The "seeded" graft at 3 months showed endothelial cells on the luminal surface as well as some intimal thickening. By 20 months, the same "seeded" graft showed significant concentric intimal thickening and by 24 months, this "seeded" graft thrombosed. The "nonseeded" graft at 16 months had irregular areas of intimal thickening which were quite patchy in nature. The flow contacting surface of the "nonseeded" graft remained thin. The intima of the "seeded" graft was twice as thick as that of the "nonseeded" graft. The methodologies implemented in the study design were appropriate. Biopsy samples were obtained without complication and were easily processed for analysis. Patient compliance with the biopsy protocol was problematic however. The study was terminated because of the development of significant concentric intimal hyperplasia in a "seeded" graft.     

Epidermoid cyst of the scalp containing human papillomavirus

Animal studies have indicated that plasma tetrafluoroethylene (TFE) may be a better prosthetic material than expanded polytetrafluoroethylene (ePTFE) for arteriovenous access in patients who require hemodialysis because it combines the advantages of both Dacron and Teflon. A randomized clinical trial to compare the two materials was conducted between May 1987 and January 1989. Forty-four patients were enrolled, 22 in each group. The status of the grafts was monitored for at least 18 months. The patency rate for plasma TFE was 59% and for ePTFE was 64%. Kaplan-Meier analysis and Wilcoxon testing revealed no statistical differences between the two groups. Four grafts became infected, two in each group, and one aneurysm developed. Despite its theoretical advantages, plasma TFE was found to be similar to ePTFE as a graft material for hemodialysis.     

Translumbar placement of inferior vena caval catheters: a solution for challenging hemodialysis access

Access to the central venous circulation for hemodialysis has traditionally been achieved via the subclavian or jugular venous routes. With ongoing improvements in medical management, many hemodialysis recipients develop exhaustion of these routes and require alternative means of central venous access. Inferior vena caval (IVC) catheters have been placed with a percutaneous translumbar approach to allow central venous access for chemotherapy, harvesting of stem cells, and total parenteral nutrition. Translumbar placement of IVC catheters has become accepted by some as a useful and reliable alternative in patients who require long-term hemodialysis but have exhausted traditional access sites. IVC catheters have been placed in patients with IVC filters, and IVC filters have been placed in patients with IVC catheters. Complications include those associated with central venous catheters, for example, sepsis, fibrin sheaths, and thrombosis. A complication specific to placement of IVC hemodialysis catheters is migration of the catheter into the subcutaneous soft tissues, retroperitoneum, or iliac veins. Translumbar placement of IVC catheters is performed only in patients considered to have few or no other medical options and is not intended as a primary means of central venous access.     

Saccharomyces cerevisiae Duo1p and Dam1p, novel proteins involved in mitotic spindle function

Recent evidence suggests that the cost as well as the morbidity associated with the maintenance of hemodialysis access is increasing rapidly; currently, the cost exceeds 1 billion dollars and access related hospitalization accounts for 25% of all hospital admissions in the U.S.A. This increase in cost and morbidity has been associated with several epidemiological trends that may contribute to access failure. These include late patient referral to nephrologists and surgeons, late planning of vascular access as well as a shift from A-V fistulaes to PTFE grafts and temporary catheters, which have a higher failure rate. The reasons for this shift in the types of access is multifactorial and is not explained by changes in the co-morbidities of patients presenting to dialysis. Surgical preference and training also appear to play an important role in the large regional variation and patency rate of these PTFE grafts. We propose a program for early placement of A-V fistulae, a continuous quality improvement, multidisciplinary program to monitor access outcome, the development of new biomaterials, and a research plan to investigate pharmacological intervention to reduce development of stenosis and clinical interventions to treat those that do develop, prior to thrombosis.     

Long-term survival of vascular accesses in a large chronic hemodialysis population

Complications associated with vascular accesses account for approximately 30% of hospital admissions for chronic hemodialysis patients. Long-term patency of access was evaluated in 76 patients, without diabetes mellitus, who had been on dialysis for at least 3 years and 41 patients, with diabetes mellitus, who had been on dialysis for over 2 years. Fistulas functioned longer than grafts (58 vs. 22 months, p < 0.01, in nondiabetics and 70 vs 22 months, p < 0.01, in patients with diabetes). Declotting or revision of restored graft function for short periods of time (< 6-10 months) and subsequent declotting was ineffective. Infections were uncommon in grafts (1 per 13.5 years of dialysis) and in fistulas (1 in 200 years of dialysis).     

Risk factors for vascular disease and arteriovenous fistula dysfunction in hemodialysis patients

Vascular access dysfunction is an important cause of morbidity for dialysis patients and a major contributor to hemodialysis cost. Thrombosis is a leading cause of vascular access failure, and usually results from stenotic lesions in the venous outflow system. This study was designed to explore the impact of serum levels of various risk factors for thrombosis and accelerated fibrointimal hyperplasia on progressive stenosis, and the subsequent thrombosis of hemodialysis fistula. A cross-sectional and 2-yr prospective pilot study was performed in 30 nondiabetic hemodialysis patients with primary arteriovenous fistula. Venous dialysis pressure, urea recirculation, color Doppler sonography, and angiography were used to monitor vascular access patency. Eleven patients (37%) developed a progressive stenosis in the venous circuit, which was complicated by thrombosis in three patients. Compared with the patients without fistula dysfunction, these patients had higher serum levels of monocyte chemoattractant protein-1 and interleukin-6, two cytokines that regulate the proliferation of vascular smooth muscle cells, which is the key mechanism in the pathogenesis of fistula stenosis. In addition, they had hyperinsulinemia, hyperlipidemia, and increased plasma levels of two hemostasis-derived risk factors for thrombosis: plasminogen activator inhibitor type 1 and factor VII. Monocyte chemoattractant protein-1, interleukin-6, plasminogen activator inhibitor type 1, factor VII, triglycerides, and the ratios for cholesterol/HDL-cholesterol, apolipoprotein (apo) A-I/ apo C-III, apo A-I/apo B, and glucose/insulin were independent predictors of fistula dysfunction. This study demonstrates the influece of cytokines, hemostasis-derived vascular risk factor, hyperinsullnemia, and abnormallties of lipids and apolipoproteins on primary fistula survival. The assessment of these factors might be useful for the identification of the patients at risk of fistula stenosis and thrombosis.