Validation of the failure to maturation equation and proposal for a novel scoring system for arteriovenous fistula maturation in multiethnic Asian haemodialysis patients

INTRODUCTION

A successful arteriovenous fistula is essential for effective haemodialysis. We aim to validate the existing failure to maturation equation and to propose a new clinical scoring system by evaluating arteriovenous fistula success predictors.

METHODS

Data of end-stage renal disease patients initiated on haemodialysis from January 2010 to December 2012 were retrospectively obtained from medical records with follow-up until 1 January 2014. Application of the failure to maturation equation was evaluated. A nomogram was developed using arteriovenous fistula success predictors and was calibrated with a bootstrapping technique.

RESULTS

A total of 694 patients were included with mean duration of follow-up of 2.3 years. Arteriovenous fistula maturation was achieved by 542 patients (78%). Comparing our cohort with the failure to maturation cohort, there were statistically significant differences in mean age, ethnicity and presence of diabetes mellitus. The failure to maturation equation failed to predict arteriovenous fistula outcomes with area under the curve performance of 0.519 on a receiver operating characteristic curve. Multivariate logistic regression showed that Malay patients (odds ratio = 0.628; 95% confidence interval = 0.403-0.978; p < 0.05) and patients requiring preoperative vein mapping (odds ratio = 0.601; 95% confidence interval = 0.410-0.883; p < 0.01) had a lower chance of arteriovenous fistula success, whereas male gender (odds ratio = 1.526; 95% confidence interval = 1.040-2.241; p < 0.05) and presence of postoperative good thrill (odds ratio = 3.137; 95% confidence interval = 2.127-4.625; p < 0.0001) had a higher chance of arteriovenous fistula success. The derived nomogram predicted arteriovenous fistula success (odds ratio = 1.030; 95% confidence interval = 1.022-1.038; p < 0.0001) with the area under the curve of 0.695 on a receiver operating characteristic curve and an adequacy index of 99.86% (p < 0.0001).

CONCLUSION

The failure to maturation equation was not validated in our cohort. The clinical utility of our proposed arteriovenous fistula scoring system requires external validation in larger studies.

A rare case of bipartite combined tumour of the oesophagus

Background

Bipartite combined oesophageal tumours are an exceedingly rare entity and much less is known about the natural history of these tumours following curative surgery. The authors present a case of a bipartite combined oesophageal tumour comprising of sarcomatoid carcinoma and small cell carcinoma with early postoperative recurrence.

Case presentation

A 63-year-old Chinese male with a smoking history presents with hemoptysis on a background of dysphagia and odynophagia for 1 month. An endoscopic evaluation found an exophytic oesophageal tumour with contact bleeding for which biopsy of this lesion returned as a malignant high-grade tumour where immunohistochemistry staining was unable to establish the lineage of the tumour. Differential diagnoses include sarcomatoid carcinoma and malignant undifferentiated sarcoma. With the provisional diagnosis of a high-grade oesopheageal sarcoma, the patient underwent minimally invasive McKeown’s oesophagectomy. Final histological assessment was pT1bN0 with two histological types of malignancy within a single tumour—70% poorly differentiated spindle cell squamous carcinoma and small cell carcinoma. He was planned for adjuvant chemotherapy in view of the small cell carcinoma component after the resolution of the postoperative infective collections. A computed tomographic scan performed 4 months postoperatively demonstrated metastasis to the lung, pleura, thoracic nodes and liver. Biopsy of the largest lung nodule confirmed small cell neuroendocrine carcinoma with features similar to the small cell carcinoma component in the prior oesophagectomy specimen. He was thereafter initiated on palliative chemotherapy aimed at three weekly carboplatin and etoposide aimed at a total of 4 cycles with peglasta support. Etoposide was stopped during the first cycle due to asymptomatic bradycardia. The regime was then converted to carboplatin with irinotecan for 5 cycles. Repeat computed tomographic scan performed 3 weeks after the completion of chemotherapy showed a complete response of lung and liver metastasis and no evidence of local recurrence or distant metastasis.

Conclusion

The management of bipartite combined oesophageal tumours should be guided by its more aggressive component. Bipartite combined oesophageal tumours with a small cell carcinoma component are believed to demonstrate aggressive tumour biology likened to that of primary oesophageal small cell carcinoma. Preoperative confirmation of a combined tumour may be challenging, and biopsy results may only yield one of the two components. The more aggressive component is usually a small cell carcinoma, for which the mainstay of therapy is platinum-based chemotherapy rather than surgery.

Catheter-related complications and survival among incident hemodialysis patients in Singapore

Introduction:

Hemodialysis is the main modality of renal replacement therapy in Singapore. However, a majority of the patients in Singapore are initiated on hemodialysis via a catheter. This study examines the complication rates and factors predicting catheter-related bloodstream infections and mortality rates in patients who were initiated on hemodialysis at our institution.

Methods:

This is a single-center retrospective analysis of incident hemodialysis patients who were initiated on renal replacement therapy between 1 January 2010 and 31 December 2012. Catheter-related bloodstream infection risk factors, organisms, and associated mortality were analyzed.

Results:

The catheter-related bloodstream infection and exit site infection incidence rates were 0.75 and 0.50 per 1000 catheter days, respectively. The mean duration to first catheter-related bloodstream infection episode was 182.47 ± 144.04 catheter days. Prolonged catheter duration was found to be a risk factor for catheter-related bloodstream infection. Compared to patients initiated on dialysis via arteriovenous fistula, initiation of dialysis via catheter is strongly associated with increased mortality (6.0% vs 14.5%; p = 0.02). In particular, the presence of diabetes mellitus and development of catheter-related bloodstream infection was associated with increased mortality ( p = 0.04 and 0.05, respectively). In addition, patients who began hemodialysis before being seen by a nephrologist were associated with decreased mortality (3.4% vs 13.0%; p = 0.03).

Conclusion:

In conclusion, prolonged duration of catheter insertion is found to be a risk factor for catheter-related bloodstream infection in hemodialysis patients, and its development is associated with increased mortality. Early referral to a nephrologist and creation of arteriovenous fistula in pre-end-stage renal disease patients are pivotal in improving the outcomes of patients.

Outcomes of arteriovenous fistula creation, effect of preoperative vein mapping and predictors of fistula success in incident haemodialysis patients: A single-centre experience

AIM

Vascular access in haemodialysis is critical for effective therapy. We aim to evaluate the outcomes of arteriovenous fistula (AVF) creation in incident haemodialysis patients, impact of preoperative vein mapping and predictors of successful AVF maturation in our centre.

METHODS

Data of End-stage Renal Disease (ESRD) patients initiated on haemodialysis from January 2010 to December 2012 in our centre were retrospectively obtained from electronic medical records and clinical notes. Demographic characteristics, medical comorbidities, perioperative details were collected, and patients were followed up until 1 January 2014.

RESULTS

A total of 708 patients (median age 64, IQR 55-72) were included with mean duration of follow up of 2.3 ± 1.2 years, with access of AVF and arteriovenous graft (AVG) in 694 (98%) and 14 (2%) patients respectively. Eight patients were lost to follow-up. Successful AVF maturation was achieved in 542 patients (78%), with 1-year cumulative patency rate of 74%. Multivariate analysis revealed male gender, upper arm AVF and good postoperative thrill and pulse as predictors of successful AVF maturation. Preoperative vein mapping was performed in 42.5% (295/694) of patients, with mean vein diameter of 2.44 ± 0.82 mm. Maturation rates with and without vein mapping were 72.2% and 82.4%, respectively, (P = 0.001). In patients with vein diameters of <2 mm and ≥2 mm, there was no statistically significant difference in maturation rates (71.3% vs. 72.6%; P = 0.887) and median maturation time (66 vs. 78 days; P = 0.73).

CONCLUSION

Arteriovenous fistula can be successfully created in most incident haemodialysis patients. Routine vein mapping is not necessary if veins are suitable on physical examination alone, and vein sizes of <2 mm on ultrasound is not associated with lower AVF maturation rate.

Apical lymph node dissection of the inferior mesenteric artery

AIM

It is controversial whether a high or low ligation of the inferior mesenteric artery (IMA) is superior. The former allows an extended lymph node clearance whereas the latter preserves the distal vascular supply via the left colic artery (LCA). Apical lymph node dissection of the IMA (ALMA) harvests nodal tissue along the IMA proximal to the LCA whilst performing a low ligation. This anatomically replicates the oncological benefit of high ligation and the vascular preservation of low ligation. Our study evaluates the nodal yield of ALMA and the short-term outcome of this technique.

METHOD

We retrospectively studied 19 patients with sigmoid or rectal cancer who underwent curative surgical resection with ALMA. All ALMAs were performed with a standard technique previously described (Kobayashi et al., Surg Endosc 2005, 20:563-9; Sekimoto et al. Surg Endosc 2010, 25:861-6) . The lymph node yield from the dissection (the ALMA specimen) was compared with the total lymph node yield. Data on the LCA anatomy, time required to perform ALMA, complications and postoperative recovery were evaluated.

RESULTS

ALMA was successful in 18 patients. Median postoperative hospitalization was 5 (2-26) days without ALMA-related morbidity or mortality. The median lymph node yield was 20 (9-41) and a median of 14.3 (0-80)% were harvested with ALMA. Two patients not having neoadjuvant chemoradiotherapy had fewer than 12 lymph nodes, excluding nodes harvested from ALMA. The average time required for ALMA was 18 min.

CONCLUSION

ALMA is a safe and feasible technique, allowing extended lymphadenectomy without sacrificing the LCA. In this small group of patients none were upstaged due to cancerous involvement of the proximal nodes.

Observation of handover process in an intensive care unit (ICU): barriers and quality improvement strategy

OBJECTIVE

To describe the characteristics and barriers in the handover process in a medical intensive care unit.

DESIGN

A cross-sectional descriptive study using a checklist to observe nurses and doctors during handover of patients in and out of the intensive care unit.

SETTING

The study was conducted at a 1000-bed tertiary hospital in Singapore. The unit admits all patients under university medicine clusters, except those needing cardiology services.

PARTICIPANTS

Handover between 90 pairs (180 participants)-50 nurse-to-nurse (100 nurses) and 40 doctor-to-doctor (80 doctors)--were passively observed in real time during morning and evening shifts over weekdays.

MAIN OUTCOME MEASURES

The number and types of distractions and their relationship to the time spent during handover, the information included during handover, and the number of working shifts.

RESULTS

The results showed that there were 1.26 (± 1.75) distractions per handover. In 45 (50%) handovers, no distraction occurred. The human factor was the most common distracting factor during handovers, whereas short message service and monitor alarms were not identified as distracting factors. The information included least often was 'do not resuscitate' (DNR). Nurses spent significantly longer during handovers than doctors.

CONCLUSION

The findings provide information for improving the handover process during the transfer of patients in and out of the intensive care unit. Distractions during handovers are common and are associated with longer durations. Nurses and doctors rarely address DNR status during handover of ICU patients in this study.

Differences in the handover process and perception between nurses and residents in a critical care setting

AIMS AND OBJECTIVES

To identify the differences in practices and perceptions of handovers between nurses and residents in the critical care setting, so as to improve the quality of the process.

BACKGROUND

Critically ill patients with complex problems are ideal for the study of handovers. However, few handover studies have been conducted in intensive care units.

DESIGN

Descriptive study using questionnaires.

METHODS

We interviewed all nurses and residents involved in handovers of patients admitted to and discharged from a medical intensive care unit over a period of one month. Interviews were guided by a questionnaire and conducted between 24-48 hours of handovers.

RESULTS

Out of 672 eligible participants, 580 (290 nurses and 290 residents) agreed to participate in the study (86·3% response rate). Compared to residents, nurses received more training on handovers, covered issues specific to allied health specialties more frequently during handovers, and reviewed patients earlier after handovers. The perceived importance of the different components of handover varied significantly: donor residents, donor nurses, recipient residents and recipient nurses emphasised the overall management plan, case complexity, management plan over the next 48 hours and past medical history, including allergies, respectively. Satisfaction in the handover was related to pre-handover review of electronic medical records, handover training and clarity level in the management plan following the handover, with only the last factor remaining significant on multivariate analysis.

CONCLUSIONS

More nurses than residents received prior training in handovers. Nursing handovers were more inclusive of allied health specialties. The perceived importance of the components of handover varied. Greater clarity in management plans was associated with better satisfaction.

RELEVANCE TO CLINICAL PRACTICE

Deficiencies in the handover process (lack of prior training in handovers, not including allied health specialties and not reviewing electronic records before handover) were identified, thus providing opportunities for mutual learning between nurses and residents.

Validation of various osteoporosis risk indices in elderly Chinese females in Singapore

INTRODUCTION

This study aimed to compare the sensitivity and specificity of various published indices for identifying elderly Chinese females at risk of osteoporosis in Singapore.

METHODS

The indices considered were the Simple Calculated Osteoporosis Risk Estimation (SCORE), the Osteoporosis Risk Assessment Instrument (ORAI), the Age Bulk One or Never Estrogens (ABONE), body weight (WEIGHT), and the Osteoporosis Self-Assessment Tool for Asians (OSTA). Altogether, 135 postmenopausal Chinese female subjects aged 55 years and older participated in the study, and their bone mineral density (BMD) was measured with dual-energy x-ray absorptiometry. Subjects were classified as osteoporotic if their femoral neck BMD T-score was -2.5 or lower. Receiver operating characteristic (ROC) curves were generated to determine the indices' cut-off points, sensitivity, and specificity.

RESULTS

OSTA had the highest discriminatory power, with an estimated area under the ROC curve of 0.82. This was followed by SCORE (0.80), WEIGHT (0.78), ORAI (0.76), and ABONE (0.70). At the cut-off point of -2, OSTA achieved sensitivity and specificity of 91% and 59%, respectively.

CONCLUSION

The study showed that OSTA is an effective index for identifying postmenopausal women at risk for osteoporosis.

Is there a role for microorganisms in the pathogenesis of sarcoidosis?

Sarcoidosis is a granulomatous disease that has the immunopathological features of being antigen-driven. It is a complex disease that appears to arise from the interaction of one or more triggers with an immunologically predisposed host. Previous reports of familial clustering and varying prevalence of sarcoidosis in different populations could reflect differences in ethnic predisposition or differences in local environmental exposures. This review focuses specifically on these areas that have been the subjects of intensive investigation recently. Specific focus is provided on the issue of an infective trigger and highlights popular candidates. It is concluded that microbes are a likely trigger (but not as an infection) in a genetically predisposed individual and that this initial event culminates in the sarcoidosis granulomatous response.

Sarcoidosis: genes and microbes--soil or seed?

Sarcoidosis is a multi-organ granulomatous disorder that is characterised by the accumulation of CD4+ T-lymphocytes resulting in a Th-1 type immune response. Although our understanding of the immune response in sarcoidosis has improved in recent years through studies of bronchoalveolar lavage cells and fluid, the genetic predisposition and trigger factors (and their interrelationship) remain unclear. Previous reports of familial clustering and varying prevalence of sarcoidosis in different populations suggested molecular epidemiological heterogeneity. This review focuses specifically on two pivotal areas that have been the subjects of intensive investigation recently: a) triggering by infective agents and b) host genetic susceptibility and relates these to broader issues of pathogenesis. It is concluded that one or more microbes behaving in a non-infectious fashion in a genetically predisposed individual trigger the sarcoidosis granulomatous response.