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PubMed2004

Outcome after autogenous brachial-axillary translocated superficial femoropopliteal vein hemodialysis access.

OBJECTIVE: The optimal configuration for patients with "complex" or "tertiary" hemodialysis access needs remains undefined. This study was designed to examine the utility of the autogenous brachial-axillary translocated superficial femoropopliteal vein access (SFV ACCESS) in this subset of patients. METHODS: Patients presenting for permanent hemodialysis access without a suitable upper extremity vein for autogenous access identified by duplex ultrasound mapping and those with repeated prosthetic access failures were considered candidates for SFV ACCESS. Ankle-brachial indices were obtained, and duplex scanning of the superficial femoropopliteal and saphenous veins was performed. Patients deemed candidates for SFV ACCESS also underwent preoperative upper extremity arteriography and venography. A retrospective review of the complete medical record was performed, and a follow-up telephone or personal interview was conducted. RESULTS: Thirty patients (mean age +/- SD, 54 +/- 15 years; male, 33%; white, 37%; with diabetes, 50%; obese, 21%) underwent SFV ACCESS among approximately 650 access-related open surgical procedures during the study period. The patients had been receiving dialysis for 4 +/- 5 years (range, 0-24 years), and had 3 +/- 3 (range, 0-17) prior permanent accesses, whereas 90% were actively dialyzed through tunneled catheters. In-hospital 30-day mortality was 3%, and the hospital length of stay was 7 +/- 7 days. Fifty-seven percent of the patients experienced some type of perioperative complication, and 38% required a remedial surgical procedure. Hand ischemia developed in 43% of the patients (severity grade: 1, 10%; 2, 7%; 3, 27%), and a distal revascularization, interval ligation was performed in all those with grade 3 ischemia. Thigh wound complications or hematomas developed in 23% of the patients, and arm wound complications or hematomas developed in 17%. The incidence of thigh wound complications was significantly greater (57% vs 9%; P =.03) in obese patients, but the other perioperative complications analyzed could not be predicted on the basis of age, gender, or comorbid conditions. The SFV ACCESS was cannulated 7 +/- 1 weeks postoperatively. The primary, primary assisted, and secondary patency rates were 96% +/- 4%, 100% +/- 0%, and 100% +/- 0%, respectively, at 6 months; 79% +/- 8%, 91% +/- 6%, and 100% +/- 0%, respectively, at 12 months; and 67% +/- 13%, 86% +/- 9%, and 100% +/- 0%, respectively, at 18 months (life table analysis; % +/- SE). CONCLUSIONS: The intermediate term functional patency rate after SFV ACCESS is excellent, although the magnitude of the procedure and the complication rate are significant. SFV ACCESS should only be considered in patients with limited access options.

Arteriovenous Shunt, Surgical↗

PubMed2005

Femoral vein transposition for arteriovenous hemodialysis access: improved patient selection and intraoperative measures reduce postoperative ischemia.

PURPOSE: Construction of prosthetic arteriovenous access for hemodialysis in the thigh results in a high incidence of graft failure and infection. Autogenous femoral artery-common femoral thigh transposition (transposed femoral vein [tFV]) arteriovenous accesses have superior patency, but our previous report documented a high incidence of ischemic events requiring secondary surgical intervention. Recent results of improved patient selection and intraoperative maneuvers to reduce ischemia are unknown. METHODS: During a 6-year period eight children (mean age, 13.3 years) and 46 adults (mean age, 52.3 years; 27 female, 19 male) underwent construction of 55 tFV thigh accesses for hemodialysis access. Adult patients were divided into groups I and II on the basis of the introduction of specific strategies to reduce the incidence of ischemic complications. In the cohort of children, steal prophylaxis included one banded femoral vein, three tapered femoral veins, two distal femoral artery pressure measurements taken before and after access construction (mean ratio, 0.70), and two closed anterior and superficial posterior compartment fasciotomies. Of the first 25 accesses in adults (group I, mean age, 55.9 years), 10 had access banding (six at the initial procedure and four in the immediate postoperative period to treat ischemia). Of the second 22 accesses (group II, mean age, 48.2 years), steal prophylaxis included 14 tapered femoral veins, 6 distal femoral artery pressure measurements (mean ratio, 0.76; range, 0.62 to 0.86), and 1 fasciotomy. Patients with significant distal occlusive disease were not offered a tFV access in the time frame of group II. RESULTS: Eight accesses in children had 100% primary functional patency at 2 years, with no reoperations for ischemia. Nine group I adult patients underwent remedial procedures to correct distal ischemia. No adult patient in group II required a remedial procedure to correct ischemia. Groups I and II 2-year secondary functional access patency was 87% and 94%, respectively. There were no access infections in either group. Femoral vein tapering significantly reduced the need for remedial correction of ischemia ( P = .03). CONCLUSIONS: Improved patient selection and selective intraoperative femoral vein tapering eliminated remedial procedures to correct ischemia in patients undergoing tFV access. Patency rates were excellent despite the liberal use of vein tapering. Transposed FV access should be considered for good risk individuals undergoing their first lower extremity access.

Adolescent↗

PubMed1997

Predictive measures of vascular access thrombosis: a prospective study.

Malfunction of permanent vascular accesses remains a cause of frequent and costly morbidity in patients receiving chronic hemodialysis (CHD). Several recommendations for routine monitoring of these permanent vascular accesses for incipient failure have been proposed. In this study, multiple indicators of incipient vascular access dysfunction, including "venous" and "arterial" pressures at serial blood flows (200 ml/min, 300 ml/min, and 400 ml/min), percent urea recirculation, Doppler ultrasound, and access blood flow by ultrasound dilution technique were simultaneously evaluated in a total of 220 vascular accesses in 170 chronic hemodialysis patients in two separate study periods (6 months apart). The rate of thrombosis was determined within the subsequent 12 weeks of each study period to assess the short-term predictive power of access thrombosis. During the period of follow-up, there were 34 thrombotic events in 172 polytetrafluoroethylene (PTFE) grafts and only one thrombotic event in 48 arterio-venous fistulas (AVF). Therefore, the statistical analysis was limited to the PTFE grafts. When grafts with thromboses were compared to those without thrombosis by univariate analysis, access blood flow measured either by ultrasound dilution technique (875 +/- 426 ml/min with thrombosis vs. 1193 +/- 677 ml/min without thrombosis, P = 0.001) or by Doppler ultrasound (762 +/- 420 ml/min with thrombosis vs. 1171 +/- 657 ml/min without thrombosis, P = 0.001) were significantly different in the two groups. There was good correlation (r = 0.79, P = 0.0001) between the blood flows determined by both techniques. The grade of stenosis determined by ultrasound was also a statistically significant predictor (P = 0.02). "Venous" and "arterial" pressures were numerically similar and were not statistically different between the accesses that did and those that did not thrombose. When multivariate analysis was used, there was a significantly increased risk of thrombosis only with decreasing access blood flow determined by ultrasound dilution techniques after adjusting for other confounding variables. When the average blood flow of all grafts (1134 ml/min) is considered as the reference access blood flow (relative risk of 1.0), the relative risk of a PTFE thrombotic event within the subsequent 12 weeks was 1.23 at a blood flow 950 ml/min, 1.67 at a blood flow of 650 ml/min and to 2.39 at a blood flow of 300 ml/min. In summary, access blood flow measured by either Dilution or Doppler is a reliable indicator of subsequent short-term thrombosis risk. Other proposed methods of evaluating access dysfunction were not useful in our patients. If simple to use, cost-effective devices to measure dialysis access blood flow become readily available, the measurement of access blood flow will likely become the method of choice for screening of PTFE vascular access dysfunction in hemodialysis patients.

Aged↗

PubMed1998

Predicting hemodialysis access failure with color flow Doppler ultrasound.

Color flow doppler ultrasound examination of the hemodialysis access was conducted in 2,792 hemodialysis patients to evaluate its value in predicting hemodialysis access failure. After baseline assessment of vascular access function with clinical and laboratory tests including color flow doppler evaluation these patients were followed for a minimal of 6 months or until graft failure occurred (defined as surgery or angioplasty intervention, or graft loss). The patient demographics and vascular accesses were typical of a standard hemodialysis patient population. On the day of the color flow doppler examination systolic and diastolic blood pressure, hematocrit, urea reduction ratio, dialysis blood flow, venous line pressure at a dialysis blood flow of 250 ml/min, and access recirculation rate were measured. At the conclusion of the study 23.5% of the patients had access failure. Case mix predictors for access failure were determined using the Cox Model. Case mix predictors of access failure were race, non-white was higher than white (p < 0.005), younger accesses had a higher risk than older accesses (p < 0.025), accesses with prior thrombosis had a higher risk of failure (p=0.042), polytetrafluoroethylene (PTFE) grafts had a higher risk than native vein fistulae (p < 0.05), loop PTFE grafts had a higher risk than straight PTFE grafts (p < 0.025), and upper arm accesses had a higher risk than forearm accesses (p=0.033). Most significant, however, was decreased access blood flow as measured by color flow doppler (p < 0.0001). The relative risk of graft failure increased 40% when the blood flow in the graft decreased to less than 500 ml/min and the relative risk doubled when the blood flow was less than 300 ml/min. This study has shown that color flow doppler evaluation, quantifying blood flow in a prosthetic graft, can identify those grafts at risk for failure. In contrast, color doppler volume flow in native AV fistulae could not predict fistula survival. This technique is noninvasive, painless, portable, and reproducible. We believe that preemptory repair of an anatomical abnormality in vascular access grafts with decreased blood flow may decrease patient inconvenience, associated morbidity, and associated costs.

Arteriovenous Shunt, Surgical↗

PubMed2002

Resistance genes in wild accessions of Triticeae--inoculation test and STS marker analyses.

Sequence tagged site (STS) markers have been developed recently to identify resistance genes in wheat. A number of wild relatives have been used to transfer resistance genes into wheat cultivars. Accessions of wild species of Triticeae: Aegilops longissima (4), Ae. speltoides (6), Ae. tauschii (8), Ae. umbellulata (3), Ae. ventricosa (3), Triticum spelta (2), T. timopheevi (3), T. boeoticum (4) and T. monococcum (1), 34 in total, were examined using PCR-STS markers for resistance genes against Puccinia recondita f.sp. tritici (Lr) and Erysiphe graminis (Pm). Additionally, a set of cv. Thatcher near-isogenic lines conferring resistance genes Lr 1, Lr 9, Lr 10, Lr 24, Lr 28, Lr 35 and Lr 37 were examined with the same procedure. Twenty-two accessions were tested using the inoculation test for resistance to Erysiphe graminis, Puccinia recondita, P. striiformis and P. graminis. The most resistant entries were those of Aegilops speltoides and Triticum timopheevi and among T. boeoticum accession #5353. Markers of all mentioned Lr resistance genes were identified in all corresponding cv. Thatcher near-isogenic lines (except Lr 35 gene marker). The following resistance gene markers were identified in wild Triticeae accessions: Lr 1 in two accessions of Ae. tauschii and one accession of Ae. umbellulata, Lr 9 in one accession of Ae. umbellulata, Lr 10 in one accession of T. spelta, Lr 28 in 11 accessions: Ae. speltoides (4), Ae. umbellulata (2), T. spelta (2) and T. timopheevi (3), Lr 37 in 3 accessions of Ae. ventricosa, Pm 1 in all 34 accessions, Pm 2 in 28 accessions, Pm 3 in all 4 accessions of T. boeoticum, 1 accession of T. spelta and 1 of T. timopheevi, and Pm 13 in 5 out of 6 accessions of Ae. speltoides. Reliability and usefulness of STS markers is discussed.

Fungi↗

PubMed2005

Access to care for chronic pain: racial and ethnic differences.

UNLABELLED: Access to medical care is a major national issue, and several surveys suggest that racial and ethnic differences influence access to care for chronic pain problems. To evaluate the influence of race and ethnicity on access to treatment for chronic pain, a cross-sectional telephone survey was performed in a nationally representative sample of 454 white, 447 African-American, and 434 Hispanic subjects with pain for > or =3 months. Questions explored demographics, pain and its treatment, and perceived access to care. A composite "access" variable combined actual consultation with perceived access. Hispanics were younger, least likely to be insured, and had the least education and lowest income; 61% spoke Spanish at home. Hispanics were significantly less likely to have consulted a primary care practitioner for pain (70%) than whites (84%) or African-Americans (85%). A lower likelihood of consultation also was associated with speaking Spanish, being male, being relatively young (18-34 years old) or single, having limited education, and not being employed. Low "access" to care was associated with being Hispanic and speaking Spanish, being younger or male, having low income or limited education, being employed, and agreeing that financial concerns prevented pain treatment. High "access" was associated with being white or African-American; being older or female or living in a suburban area; having insurance, higher income, or college education; and being unemployed. In multivariate models, low "access" was associated with Hispanic ethnicity and agreement that financial concerns prevented pain treatment. High "access" was associated with more severe pain, having insurance or an income of US 25,000 dollars to US 74,000 dollars, and agreeing that "A doctor or other health care provider is the first person I would go to to discuss my pain." These data suggest that race/ethnicity, other demographic characteristics, and socioeconomic factors influence access to pain care. Hispanic ethnicity predicts limited access. PERSPECTIVE: The influence of race and ethnicity on access to health care is a major issue in the United States. A national telephone survey suggests that race and ethnicity, along with other demographic and socioeconomic factors, influence access to care for chronic pain.

Adolescent↗

PubMed1998

Healthcare organizational change: implications for access to care and its measurement.

OBJECTIVES: To summarize evidence from peer-reviewed literature on access to care for vulnerable HMO enrollee populations; to discuss the potential effect of recent HMO and physician organization changes on access to care and its measurement. STUDY DESIGN: Review and summary of peer-reviewed literature for two HMO populations: those with chronic conditions and diseases, and those subject to discrimination due to income, color, or ethnic background. I also reviewed and summarized literature on three major changes in capitated organizations (HMOs and capitated physician organizations) that could affect access to care for vulnerable populations, and summarized findings from healthcare manager interviews conducted for several recent research projects on health system change. PRINCIPAL FINDINGS: Although mixed, there are enough negative results to raise some concerns about access to care for HMO enrollees with chronic conditions and diseases. Several emerging organizational changes have the potential to change access to care for the vulnerable HMO enrollees. The shift in cost-cutting from fragmented clinical management of specific services at a point in time toward more integrated clinical management of all services for specific types of patients across time may improve access to care, as may increased efforts to attract and retain HMO enrollees. The increased importance of capitated provider organizations within the health system may restrict access in some ways, and expand access in others. CONCLUSIONS: Organizational changes can affect both access to care and its measurement. More research is needed on the effects of these changes on access to care and quality of care. For researchers examining access to care for vulnerable HMO enrollee populations, these changes create challenges to determine the most appropriate measures of access to care, and the most appropriate organizations and organizational characteristics to measure. RELEVANCE TO CLINICAL PRACTICE, MANAGEMENT, AND/OR POLICY: Changes in market competition are leading to organizational changes that affect access to care for vulnerable HMO enrollee populations. Public and/or private policies that improve measurement and reporting can affect market competition and improve access to care.

Capitation Fee↗

PubMed2004

Impaired hyperemic response is predictive of early access failure.

The aim of this study was to demonstrate that hyperemic response is a predictor of access failure. We conducted a review of a prospective database of dialysis access patients with preoperative hyperemia studies from June 1998 to August 2002. These consisted of bilateral brachial artery pressures followed by flow velocity measurements of the brachial artery and radial artery at rest and after 3 min of arm ischemia. Measurements were taken by using a cuff placed above the antecubital fossa and inflated to 20 mmHg above systolic pressure. There were no differences recorded in brachial artery pressures for the bilateral studies. Hyperemic response was entered into a stepwise Cox regression to determine its effect on access failure. Access failure was defined as failure to mature or thrombosis. Accesses were placed according to Dialysis Outcome Quality Intiatives (DOQI) guidelines. Kaplan-Meier survival analysis was performed. Log-rank testing was used to compare patency results. Censored end points were death, renal transplant, and access survival to the end of the study period. Fistulas that failed to mature were considered failures at 3 months. Arteries with a <5 cm/sec increase in peak systolic velocity were defined as nonresponders. The 59 arteries used for dialysis access were divided into two groups on the basis of their hyperemic response in cm/sec. The nonresponders were compared with the remainder of accesses performed. Accesses based on arteries with absent or minimal hyperemic response had significantly lower (p < 0.0005) secondary patencies by Kaplan-Meier analysis. Upon further stratification into radial and brachial arteries, the significant difference in secondary patency remained for radial artery--based accesses (p = 0.024) and approached statistical significance for brachial artery--based accesses (p = 0.057). A significant difference was not seen in primary patencies, indicating that accesses based on arteries with an acceptable hyperemic response are more likely to be salvaged by revisions. A nonresponsive radial artery was not a significant predictor of a nonresponsive brachial artery in the same extremity by binary logistic regression (p = 0.111), and a nonresponsive artery was not a significant predictor of nonresponsiveness in the corresponding artery in the contralateral extremity (p = 0.137). Cox regression analysis revealed that the hyperemic response is a significant predictor of failure to mature or thrombosis. Hyperemic testing is a useful means of evaluating adequate arterial inflow for dialysis access. Reduced or absent hyperemic response is an independent predictor of access failure.

Adolescent↗

PubMed2005

Vascular access as a determinant of adequacy of dialysis.

Vascular accesses consist of permanent arteriovenous (AV) accesses (autogenous fistulas and synthetic grafts) and venous accesses (central venous catheters [CVCs]). AV accesses have fewer complications than venous accesses, and are therefore the preferred hemodialysis access. An important additional issue is whether the type of access influences adequacy of dialysis (i.e. Kt/V). Key limiting factors in delivering adequate Kt/V are blood pump speed (Q(B) ), access recirculation, and treatment time. In general, AV accesses support higher Q(B)S with less negative inflow arterial pressures than CVCs. Well-functioning AV accesses are also less likely to exhibit recirculation. Nevertheless, recirculation commonly develops when AV accesses (usually grafts) develop stenosis with decreased access blood flow. Although extension of treatment time can offset the effects of reduced Q(B) and recirculation, this is often impractical and poorly accepted by patients. In conclusion, AV accesses are superior to venous accesses because they are less prone to complications and are more likely to deliver prescribed Kt/V within prescribed treatment time.

Blood Vessel Prosthesis Implantation↗

PubMed1992

A population-based, multivariate analysis of the association between 911 access and per-capita county trauma death rates.

STUDY OBJECTIVE: Decreased response times for injury should decrease the morbidity and mortality of trauma. The 911 telephone access is designed to improve the response time for emergencies. The purpose of this study was to analyze the association between county 911 access and per-capita county trauma death rates. METHODS: Data on all trauma deaths from 1986 through 1988 were obtained from the North Carolina Medical Examiner's data base. Counties were divided into those that had 911 access during the entire study period (15), those that never had 911 access (62), and those that installed 911 during 1987 (ten). Counties obtaining 911 access in 1986 or 1988 were excluded (13). RESULTS: The per-capita trauma death rate in counties that had 911 access throughout the study was 4.3 +/- 0.8 versus 5.0 +/- 1.1 per 10,000 population in counties that never had 911 access (P less than .01). Compared with counties with 911 access, counties without 911 were more rural, were less likely to have a trauma center, and were less likely to have advanced life support certification (P less than .03 for all). Controlling for these other factors, multivariate analysis demonstrated that 911 access had no significant independent association with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant change occurred in per-capita county trauma death rates after implementation of 911. CONCLUSION: Although counties with 911 access had lower trauma death rates by t-test, multivariate analysis showed no significant independent association of 911 access with per-capita county trauma death rates. In the ten counties that implemented 911 access in 1987, no significant changes in trauma death rates occurred after implementation. Although other factors may explain these findings, this study showed no significant independent impact of 911 access on per-capita county trauma death rates.

Emergency Medical Service Communication Systems↗

PubMed2001

Ultrasound dilution evaluation of pediatric hemodialysis vascular access.

BACKGROUND: Hemodialysis access thrombosis is a significant cause of morbidity for hemodialysis patients and results from decreased access flow caused by venous outflow tract stenosis. Ultrasound dilution (UD) is a practical, noninvasive, and reliable indicator of access flow and is effective in predicting venous stenosis in adult patients receiving hemodialysis. METHODS: The current study is the first to our knowledge to evaluate the accuracy of UD in predicting hemodialysis access stenosis in a pediatric hemodialysis population. Thirteen pediatric patients receiving hemodialysis via permanent access (4 AVF and 9 AVG) received 73 UD measurements over three months. RESULTS: Mean raw access flow (QA) was 720 +/- 428 mL/min, and mean corrected access flow (QAcorr) was 886 +/- 537 mL/min/1.73 m(2). QAcorr was significantly lower in accesses with stenosis (401 +/- 176 mL/min/1.73 m(2)) versus accesses without stenosis (1158 +/- 330 mL/min/1.73 m(2), P < 0.0001). Unlike flow values reported by raw QA, there was no overlap in flow values reported by QAcorr in accesses with stenosis (174 to 579 mL/min/1.73 m(2)) versus accesses without stenosis (709 to 1711 mL/min/1.73 m(2)). Two patients with an AVG who had QAcorr less than 600 mL/min/1.73 m(2) developed an access thrombosis within one week after UD measurement. No patients with QAcorr greater than 700 mL/min/1.73 m(2) developed access thrombosis in the 30 days following UD measurement. CONCLUSIONS: : The current study supports the use of monthly UD measurement to prevent access thrombosis in children receiving hemodialysis.

Arteriovenous Shunt, Surgical↗

PubMedDate not supplied

Evidence-based data for the hemodialysis access surgeon.

The National Kidney Foundation Dialysis Outcomes Quality Initiative Clinical Practice Guidelines for Vascular Access (DOQI) have defined the access-related care for patients with end-stage renal disease (ESRD). However, the standard of care across the country has fallen short of the DOQI targets. One potential explanation for these shortcomings is the lack of compelling evidence in the literature to support the recommendations. This study was designed to compare the DOQI with the best available evidence in the literature for four clinical questions relevant to the hemodialysis access surgeon: the choice of access type (autogenous versus prosthetic), the type of prosthetic graft, management of the "failing" (nonthrombosed) access, and management of the thrombosed access. The electronic literature databases MEDLINE and Evidence-Based Medicine Reviews were searched and relevant randomized controlled trials or meta-analyses were identified for review. No randomized controlled trials comparing autogenous to prosthetic accesses were identified. However, a recent systematic review reported that the patency rates for upper extremity autogenous accesses were superior to their polytetrafluoroethylene (PTFE) counterparts. The identified randomized trials suggested that the patency rates for the different types of commercially available prosthetic grafts used for access appear comparable. They suggested that standard wall PTFE thickness and prosthetic anastomotic cuffs may be associated with better graft patency, while venous cuffs may be associated with worse patency. Furthermore, the trials suggested percutaneous angioplasty of "failing" prosthetic accesses with greater than 50% stenoses did not appear to improve patency and that routine use of intraluminal stents, as an adjunct to angioplasty, was not beneficial. They did suggest that patency after open surgical revision of "failing" prosthetic accesses was superior to that after percutaneous angioplasty. Lastly, the identified trials suggested that the patency rates after open surgical revision of thrombosed prosthetic accesses was better than after endovascular treatment. Despite the magnitude of hemodialysis-related access problems, the quality of the evidence supporting the clinical decisions relevant to the access surgeon is limited and further clinical trials are justified.

Arteriovenous Shunt, Surgical↗

PubMedDate not supplied

Percutaneous central venous access for resuscitation in trauma.

OBJECTIVE: To determine the safety of percutaneous central venous access when used for trauma resuscitation and whether the initial hemodynamic status of the patient or the site of placement affects the ease or success of line placement. METHOD: Consecutive major-trauma patients were managed using a resuscitation protocol guiding intravenous line use. Percutaneous peripheral venous access was initially attempted in all patients. If this approach was unsuccessful or proved to be inadequate for volume resuscitation, venous access was attempted using central venous catheter-introducer sets. The site of the central venous access was determined by protocol. For thoracic injury, access was via the ipsilateral subclavian vein (SCV), the ipsilateral internal jugular vein (IJV), or the femoral vein. For suspected mediastinal injury, access was via the contralateral SCV or IJV, or the femoral vein. For abdominal or flank injury, access was via the SCV or IJV only. Multiple central venous access sites were used at the discretion of the trauma team. RESULTS: Central venous access was successful at 144 of 147 sites (99%) used in 122 patients during the study period. There was only one major complication (rate = 0.7%; 95% CI 0.0-3.8%). Mean catheter placement time was 1.9 minutes, and cannulation occurred with a mean of 1.8 needle passes. Most patients (81/122) were hypotensive (blood pressure < or = 90 torr) at the time of line placement, including 44 who were in cardiac arrest and four awake patients who had no obtainable blood pressure. Neither the access site nor the presence of hypotension was associated with the mean time to obtain central venous access, the mean number of attempts, or the complication rate. CONCLUSION: Percutaneous central venous access is relatively safe and reliable for gaining intravenous access when resuscitating trauma patients, when used in a center where physicians are experienced in the technique. Consideration should be given to expanding the use of central venous access in trauma resuscitation.

Adult↗

PubMed1998

The hemodialysis access: preferences and concerns of patients, dialysis nurses and technicians, and physicians.

One hundred twenty-eight hemodialysis patients and 64 medical personnel consisting of dialysis nurses and technicians, hemodialysis access surgeons and nephrologists were surveyed about their preferences and concerns in regard to the hemodialysis vascular access. The access preferred by physicians was the A-V fistula in the lower arm. In contrast, the access preferred by dialysis nurses and technicians was the polytetrafluoroethylene (PTFE) graft in the lower arm. Patients desired a superficial access in the forearm which was easy to cannulate, had minimal effect on their appearance, provided quick hemostasis after dialysis and enabled arm comfort during dialysis. Physicians felt the most significant concerns about the access were thrombosis and infection. Nurses and technicians ranked difficult cannulation and insufficient access blood flows that prohibited dialysis adequacy as their major problems. For patients the most common problem was pain during needle insertion. This survey concluded that the A-V fistula remains the access of choice. However, appropriate maturation of the fistula must occur before needle insertion is attempted. An immature fistula is difficult to cannulate, has fragile veins resulting in blood leakage around the needle infiltrating the subcutaneous tissues and has inadequate blood flows for successful dialysis. Patients who are introduced to dialysis with inadequate access function or access failure from either an A-V fistula or a PTFE graft have increased morbidity, inadequate dialysis and enhanced anxiety about dialysis treatments. To increase the success and acceptance of A-V fistulas in hemodialysis patients it is incumbent upon the nephrologist to protect the future access arm from damage to the vasculature and to allow for fistula maturation before cannulation. Surgical protocols must improve the appropriate selection of a fistula or PTFE graft for various age groups and disease categories. Better patient preparation and selection of the proper access type for each patient will enhance early access function and subsequent access survival.

Arteriovenous Shunt, Surgical↗

PubMed2000

Interlibrary loan in primary access libraries: challenging the traditional view.

INTRODUCTION: Primary access libraries serve as the foundation of the National Network of Libraries of Medicine (NN/LM) interlibrary loan (ILL) hierarchy, yet few published reports directly address the important role these libraries play in the ILL system. This may reflect the traditional view that small, primary access libraries are largely users of ILL, rather than important contributors to the effectiveness and efficiency of the national ILL system. OBJECTIVE: This study was undertaken to test several commonly held beliefs regarding ILL system use by primary access libraries. HYPOTHESES: Three hypotheses were developed. HI: Colorado and Wyoming primary access libraries comply with the recommended ILL guideline of adhering to a hierarchical structure, emphasizing local borrowing. H2: The closures of two Colorado Council of Medical Librarians (CCML) primary access libraries in 1996 resulted in twenty-three Colorado primary access libraries' borrowing more from their state resource library in 1997. H3: The number of subscriptions held by Colorado and Wyoming primary access libraries is positively correlated with the number of items they loan and negatively correlated with the number of items they borrow. METHODS: The hypotheses were tested using the 1992 and 1997 DOCLINE and OCLC data of fifty-four health sciences libraries, including fifty primary access libraries, two state resource libraries, and two general academic libraries in Colorado and Wyoming. The ILL data were obtained electronically and analyzed using Microsoft Word 98, Microsoft Excel 98, and JMP 3.2.2. RESULTS: CCML primary access libraries comply with the recommended guideline to emphasize local borrowing by supplying each other with the majority of their ILLs, instead of overburdening libraries located at higher levels in the ILL hierarchy (H1). The closures of two CCML primary access libraries appear to have affected the entire ILL system, resulting in a greater volume of ILL activity for the state resource library and other DOCLINE libraries higher up in the ILL hierarchy and highlighting the contribution made by CCML primary access libraries (H2). CCML primary access libraries borrow and lend in amounts that are proportional to their collection size, rather than overtaxing libraries at higher levels in the ILL hierarchy with large numbers of requests (H3). LIMITATIONS: The main limitations of this study were the small sample size and the use of data collected for another purpose, the CCML ILL survey. CONCLUSIONS: The findings suggest that there is little evidence to support several commonly held beliefs regarding ILL system use by primary access libraries. In addition to validating the important contributions made by primary access libraries to the national ILL system, baseline data that can be used to benchmark current practice performance are provided.

Benchmarking↗

PubMed2004

Vascular access stenosis: comparison of arteriovenous grafts and fistulas.

BACKGROUND: Vascular access stenosis is a frequent problem in hemodialysis patients. There is little published literature comparing the features of stenosis between arteriovenous fistulas and grafts, relative outcomes of elective angioplasty, and clinical factors predictive of access patency after angioplasty. METHODS: Prospective data were collected for all patients referred for a fistulogram during a 2-year period because of suspected access stenosis. Angioplasty was performed if there was greater than 50% stenosis. For each procedure, we recorded the number and location of stenotic lesions, degree of stenosis (on a scale of 1 to 4), and ratio of access to systemic systolic pressure. All subsequent access procedures were tracked prospectively to calculate intervention-free access survival. Multivariable analysis was used to evaluate clinical factors affecting access patency after angioplasty. RESULTS: Five hundred forty-three fistulograms were obtained: 358 in grafts and 185 in fistulas. The likelihood of finding a significant stenosis was substantially lower in fistulas than grafts (39.4% versus 68.7%; P < 0.001). Among patients with a significant stenosis, those with fistulas were less likely to have 2 or more stenotic lesions (12.5% versus 33.1%; P < 0.001). After angioplasty, degree of stenosis (1.35 +/- 0.70 versus 1.23 +/- 0.52) and access to systemic pressure ratio (0.34 +/- 0.15 versus 0.32 +/- 0.14) were similar between fistulas and grafts. Intervention-free survival was similar for fistulas and grafts (median survival, 7.5 versus 6.2 months; P = 0.36). Using multivariable stepwise proportional hazard regression analysis, only female sex, residual access stenosis, and postangioplasty access pressure ratio greater than 0.4 significantly predicted access survival (P = 0.0006). CONCLUSION: The positive predictive value of clinical evaluation for access stenosis is substantially lower for fistulas than grafts. The technical success of angioplasty and subsequent primary patency are similar for fistulas and grafts. Finally, female sex, residual stenosis, and high postprocedure access pressure ratio are each predictive of shorter access patency after elective angioplasty.

Angiography↗

PubMed2006

Comparison of perceived and modelled geographical access to accident and emergency departments: a cross-sectional analysis from the Caerphilly Health and Social Needs Study.

BACKGROUND: Assessment of the spatial accessibility of hospital accident and emergency departments as perceived by local residents has not previously been investigated. Perceived accessibility may affect where, when, and whether potential patients attend for treatment. Using data on 11,853 respondents to a population survey in Caerphilly county borough, Wales, UK, we present an analysis comparing the accessibility of accident and emergency departments as reported by local residents and drive-time to the nearest accident and emergency department modelled using a geographical information system (GIS). RESULTS: Median drive-times were significantly shorter in the lowest perceived access category and longer in the best perceived access category (p < 0.001). The perceived access and GIS modelled drive-time variables were positively correlated (Spearman's rank correlation coefficient, r = 0.38, p < 0.01). The strongest correlation was found for respondents living in areas in which nearly all households had a car or van (r = 0.47, p < 0.01). Correlations were stronger among respondents reporting good access to public transport and among those reporting a recent accident and emergency attendance for injury treatment compared to other respondents. Correlation coefficients did not vary substantially by levels of household income. Drive-time, road distance and straight-line distance were highly inter-correlated and substituting road distance or straight-line distance as the GIS modelled spatial accessibility measure only marginally decreased the magnitude of the correlations between perceived and GIS modelled access. CONCLUSION: This study provides evidence that the accessibility of hospital-based health care services as perceived by local residents is related to measures of spatial accessibility modelled using GIS. For studies that aim to model geographical separation in a way that correlates well with the perception of local residents, there may be minimal advantage in using sophisticated measures. Straight-line distance, which can be calculated without GIS, may be as good as GIS-modelled drive-time or distance for this purpose. These findings will be of importance to health policy makers and local planners who seek to obtain local information on access to services through focussed assessments of residents' concerns over accessibility and GIS modelling.

Cross-Sectional Studies↗

PubMed2004

Web content accessibility of consumer health information web sites for people with disabilities: a cross sectional evaluation.

BACKGROUND: The World Wide Web (WWW) has become an increasingly essential resource for health information consumers. The ability to obtain accurate medical information online quickly, conveniently and privately provides health consumers with the opportunity to make informed decisions and participate actively in their personal care. Little is known, however, about whether the content of this online health information is equally accessible to people with disabilities who must rely on special devices or technologies to process online information due to their visual, hearing, mobility, or cognitive limitations. OBJECTIVE: To construct a framework for an automated Web accessibility evaluation; to evaluate the state of accessibility of consumer health information Web sites; and to investigate the possible relationships between accessibility and other features of the Web sites, including function, popularity and importance. METHODS: We carried out a cross-sectional study of the state of accessibility of health information Web sites to people with disabilities. We selected 108 consumer health information Web sites from the directory service of a Web search engine. A measurement framework was constructed to automatically measure the level of Web Accessibility Barriers (WAB) of Web sites following Web accessibility specifications. We investigated whether there was a difference between WAB scores across various functional categories of the Web sites, and also evaluated the correlation between the WAB and Alexa traffic rank and Google Page Rank of the Web sites. RESULTS: We found that none of the Web sites we looked at are completely accessible to people with disabilities, i.e., there were no sites that had no violation of Web accessibility rules. However, governmental and educational health information Web sites do exhibit better Web accessibility than the other categories of Web sites (P < 0.001). We also found that the correlation between the WAB score and the popularity of a Web site is statistically significant (r = 0.28, P < 0.05), although there is no correlation between the WAB score and the importance of the Web sites (r = 0.15, P = 0.111). CONCLUSIONS: Evaluation of health information Web sites shows that no Web site scrupulously abides by Web accessibility specifications, even for entities mandated under relevant laws and regulations. Government and education Web sites show better performance than Web sites among other categories. Accessibility of a Web site may have a positive impact on its popularity in general. However, the Web accessibility of a Web site may not have a significant relationship with its importance on the Web.

Cross-Sectional Studies↗