Regional citrate anticoagulation vs systemic heparin anticoagulation for double-filtration plasmapheresis

INTRODUCTION

Double-filtration plasmapheresis (DFPP) has been utilized for immunomodulation in kidney transplantation. Anticoagulation is important to maintain circuit patency during DFPP. We aimed to compare the efficacy and safety of regional citrate anticoagulation (RCA) with systemic heparin anticoagulation during DFPP in kidney transplant recipients.

METHODS

A retrospective cohort study was conducted to compare the efficacy and safety of RCA (RCA-DFPP) to systemic heparin anticoagulation (Hep-DFPP) for DFPP among kidney transplant recipients in a single tertiary center.

RESULTS

A total of 112 sessions of DFPP were performed for 23 subjects, of which 62 sessions were RCA-DFPP and 50 sessions were Hep-DFPP. There were 13 sessions (11.6%) of premature circuit clotting, 10 sessions (16.1%) for RCA-DFPP and 3 sessions (6.0%) for Hep-DFPP (P = .10). All premature circuit clotting episodes occurred in subjects who underwent DFPP through a vascular catheter. Premature circuit clotting was associated with the use of a vascular catheter (odds ratio [OR] 14.2, 95% confidence interval [CI] 2.7-73.7; P < .01) and high postfilter ionized calcium (OR 12.7, 95% CI 1.4-112.5; P < .01). There was no major bleeding event. Hep-DFPP was associated with higher occurrence of hypocalcemia (OR 1.1, 95% CI 1.0-1.2; P < .01) and metabolic acidosis (OR 1.4, 95% CI 1.2-2.0; P = .04), while hypomagnesemia was more common for RCA-DFPP (OR 2.9, 95% CI 1.1-7.4; P = .03).

CONCLUSION

Amongst kidney transplant patients who receive DFPP therapy, RCA-DFPP may be comparable to Hep-DFPP for the maintenance of circuit patency. Functioning vascular access is vital in avoiding premature clotting of the circuit. Close monitoring of electrolyte imbalances and coagulopathy related to DFPP is recommended.

The use of medium cutoff dialyzers in patients with multiple myeloma and acute kidney injury requiring hemodialysis: A systematic review

BACKGROUND

Patients with multiple myeloma and high serum levels of circulating free light chains (FLC) have increased risk of acute kidney injury (AKI) secondary to cast nephropathy and is associated with poor survival. Despite removal of FLC by medium cutoff (MCO) dialyzer, the role of MCO hemodialysis (HD) in the treatment of cast nephropathy and its clinical benefits remain unknown.

METHODS

A systematic review was conducted to establish the effectiveness of MCO dialyzer and clinical outcomes, compared to other forms of dialyzers in the removal of FLC, in myeloma patients with AKI. The primary outcome was effectiveness of MCO-HD in reducing serum FLC. The secondary outcomes were HD independence, estimated glomerular filtrate rate, mortality rates, length of hospitalization, rebound of serum FLC before the next dialysis, removal of other molecules during dialysis, and adverse events.

RESULTS

We identified three case series, with a total of 17 patients. There were no randomized controlled trials (RCTs) or cohort studies. These case series showed that MCO dialyzer was effective in the removal of FLC and led to a reduction in FLC concentration post-dialysis. The majority of the case series did not have comparator arm and renal and/or other clinical outcomes.

CONCLUSION

MCO dialyzer appeared to be effective in the removal of FLC based on the existing limited data. However, more data, particularly large-scale RCTs, are needed to assess the use of MCO dialyzer in reducing serum FLC and its effect on clinical outcomes in patients with multiple myeloma and AKI.

Regional Citrate Anticoagulation during Double-Filtration Plasmapheresis in Kidney Transplant Recipients: A Single-Center Retrospective Cohort Study

INTRODUCTION

Double-filtration plasmapheresis (DFPP) may be used for immunomodulation in kidney transplant (KTx). While DFPP reduces plasma product exposure, risk of circuit clotting merits adequate anticoagulation. Regional citrate anticoagulation (RCA) avoids the risks of systemic anticoagulation, but a protocol for RCA-DFPP is not previously widely described.

METHODS

We conducted a single-center retrospective cohort study involving adult (≥21 years old) KTx recipients who underwent RCA-DFPP from 2018 to 2020 to investigate efficacy and safety for an RCA protocol during DFPP in KTx recipients.

RESULTS

Fifty-one (85%) of 60 RCA-DFPP sessions in 17 patients completed without circuit clotting. Circuit clotting was associated with high post-filter ionized calcium (28 vs. 3.7%, odds ratio 10.1, 95% CI 1.1-89.4, p = 0.037). Hypo- and hypercalcemia developed in 5 (8.3%) and 8 (13.3%) sessions, respectively, but no adverse effects were noted despite severe hypocalcemia in one. There was no significant change in pre- and post-RCA-DFPP sodium, bicarbonate, albumin, and platelet levels. With regards DFPP procedure, prolongation of prothrombin time (PT) and activated partial thromboplastin time (aPTT) was observed following 38 (64.4%) and 12 (20.3%) sessions, respectively. Severely prolonged (>1.5 × upper limit normal) PT and aPTT were recorded in 2 sessions each. Expectedly, hypofibrinogenemia developed after 31 (51.7%) sessions: including 4 (6.7%) severe hypofibrinogenemia (<0.5 g/L). Two patients developed bleeding requiring blood product transfusion. The median total volume of fluids administered per session was 1.495 (1.373-1.612) L; post-RCA-DFPP significant weight gain of 0.5 (0-1.25) kg was noted. Diuretic was commenced or dose increased following 20 (33.3%) sessions for fluid balance management.

DISCUSSION/CONCLUSION

Protocol-based RCA for DFPP is feasible and safe in KTx recipients. However, DFPP-related coagulopathy can develop consequent to treatment; caution should be exercised for patients with bleeding risk. Close monitoring and management of the patients' electrolytes, especially hypocalcemia and hypomagnesemia, and fluid status is recommended.

Improvement in quality of life among Sri Lankan patients with haemorrhoids after invasive treatment: a longitudinal observational study

Background

Haemorrhoids is a common chronic disease that can significantly impact patients’ quality of life. Yet, few studies have evaluated health-related quality of life (HRQoL) of patients with haemorrhoids before and after treatment. This study investigated the HRQoL of patients with haemorrhoids before and after treatment and the change in HRQoL from baseline.

Methods

A prospective observational study of patients with haemorrhoids was conducted at two public hospitals in Kandy, Sri Lanka. Two questionnaires assessing symptom severity and haemorrhoid-specific QoL were administered at initial consultation and at 4- and 8-week follow-ups after treatment (sclerotherapy, rubber band ligation (RBL), haemorrhoidectomy or evacuation of haematoma). The primary outcome was the least squares (LS) change of HRQoL score from baseline, measured using the Short Health Scale adapted for Haemorrhoidal Disease (4 domains: symptom load, interference with daily activities, concern, general well-being).

Results

In 48 patients selected for this study, LS mean change from baseline showed significant improvement in HRQoL across all domains and total Short Health Scale adapted for Haemorrhoidal Disease score at 4- and 8-week follow-ups (P < 0.001). Difference in LS mean change from baseline also showed continued improvement of HRQoL from week 4 to week 8 (P < 0.010). ‘Concern’ showed greatest improvement at 4 and 8 weeks (P < 0.001). Averaged LS mean changes from baseline showed RBL had greater improvement of HRQoL compared with sclerotherapy (P = 0.004).

Conclusion

Patients with haemorrhoids had improved HRQoL after invasive treatment. Haemorrhoid-specific QoL is an important component of the extent of disease and can serve as an aid to guide treatment, assess outcomes and monitor disease.

Description of parallel and sequential configurations for concurrent therapeutic plasma exchange and continuous kidney replacement therapy in adults

Therapeutic plasma exchange (TPE) and continuous kidney replacement therapy (CKRT) are extracorporeal therapeutic procedures often implemented in management of patients. Critically ill patients may be afflicted with disease processes that require both TPE and CKRT. Performing TPE discontinuous with CKRT is technically easier, however, it disrupts CKRT and may compromise with CKRT efficiency or hemofilter life. Concurrent TPE with CKRT offers several advantages including simultaneous control of disease process and correction of electrolyte, fluid, and acid-base disturbances that may accompany TPE. Additionally, TPE may be performed by either centrifugation method or membrane plasma separation method. The technical specifications of these methods may influence the methodology of concurrent connections. This report describes and reviews two different approaches to circuit arrangements when establishing concurrent TPE and CKRT.

A cellular and proteomic approach to assess proteins extracted from cryopreserved human amnion in the cultivation of corneal stromal keratocytes for stromal cell therapy

Background

Human corneal stromal keratocytes propagated in culture media supplemented with human amnion extract (AME) can correct early corneal haze in an animal model. Clinical application of cultivated keratocytes is limited by infectious disease screening before amnion products can be used in humans. It remains unclear if AME from cryopreserved versus fresh human amnion can support human keratocyte propagation, and which components of the extract promote keratocyte growth.

Methods

Three placentas were collected for the preparation of fresh and cryopreserved amnion tissues followed by homogenization and protein extraction. AME protein profiles were studied using isobaric tagging for relative and absolute quantitation (iTRAQ) proteomics. Enriched gene ontology (GO) terms and functional classes were identified. Primary human keratocytes from 4 donor corneas were cultured in media supplemented with fresh AME (F-AME) or cryopreserved AME (C-AME). Cell viability, proliferation and keratocyte marker expression were examined by confocal immunofluorescence and flow cytometry.

Results

AME proteomics revealed 1385 proteins with similar expression levels (between 0.5- and 2-fold) between F- and C-AME, while 286 proteins were reduced (less than 0.5-fold) in C-AME. Enriched GO term and biological pathway analysis showed that those proteins with comparable expression between F-AME and C-AME were involved in cell metabolism, epithelial-mesenchymal transition, focal adhesion, cell-extracellular matrix interaction, cell stress regulation and complement cascades. Human corneal stromal keratocytes cultured with F-AME or C-AME showed similar morphology and viability, while cell proliferation was mildly suppressed with C-AME (P > 0.05). Expression of aldehyde dehydrogenase 3A1 (ALDH3A1) and CD34 was similar in both cultures.

Conclusion

AME from cryopreserved amnion had limited influence on keratocyte culture. It is feasible to use protein extract from cryopreserved amnion to propagate human keratocytes for potential translational applications.

Renal outcomes of intensive care burn patients in an Asian tertiary centre

INTRODUCTION

Acute kidney injury (AKI) is a frequent complication of severe burn injury and is associated with a high mortality rate of up to 80%. We aimed to establish the incidence, mortality rate, and factors related to mortality in adult patients with severe burn injury and AKI with renal replacement therapy (RRT) in Singapore.

METHODS

We performed a retrospective cohort study of severely burned patients who were admitted to the Burns Intensive Care Unit (BICU) at the Singapore General Hospital (SGH) from January 2008 to December 2016. We compared patients with AKI with RRT who survived with those who did not survive. As there were changes in the protocol for burns management after 2013, we also compared patients with AKI with RRT who survived with non-survivors in each of the 2008-2012 and 2013-2016 cohorts.

RESULTS

Data of 201 patients were studied. The incidence of AKI with RRT use in severe burn injury was 21.9% and their mortality rate was 50.0%. The non-survivors had significantly higher median burned total body surface area (p = 0.043), earlier AKI (p = 0.046), earlier use of RRT (p = 0.035), lower rate of renal recovery (p = <0.0001), higher rates of adult respiratory distress syndrome (ARDS) (p = 0.005) and shock with vasopressors (p = 0.009) compared to the survivors. The survival rate was 36.8% in the 2008-2012 cohort, but improved to 60.0% in the 2013-2016 cohort. In the 2008-2012 cohort, the non-survivors developed AKI earlier (day 0 admission vs. day 3 admission, p = 0.039), and were initiated on RRT at lower serum creatinine level (173.5 μmol/L vs. 254.0 μmol/L, p = 0.042), when compared to the survivors in this same cohort. On the other hand, there were no significant differences in the renal status and fluid balance parameters between the non-survivors and survivors in the 2013-2016 cohort.

CONCLUSIONS

The incidence of AKI with RRT in the Singapore study cohort was high, but their mortality rate was relatively lower compared to other study cohorts. Severity of AKI and use of RRT were associated with poor prognosis. Large scale study is required to further study the risk factors for mortality in this group of patients and establish cause-and-effect relationship.

A prospective study of clinical characteristics and outcomes of acute kidney injury in a tertiary care Centre

Background

Acute kidney injury (AKI) is a major global health problem. We aim to evaluate the epidemiology, risk factors and outcomes of AKI episodes in our single centre.

Methodology

We prospectively identified 422 AKI and acute on chronic kidney disease episodes in 404 patients meeting KDIGO definitions using electronic medical records and clinical data from 15th July to 22nd October 2016, excluding patients with baseline estimated GFR (eGFR) of < 15 mL/min. Patients were followed up till 6 months after AKI diagnosis.

Results

The mean age was 65.8 ± 14.1. Majority of patients were male (58.2%) of Chinese ethnicity (68.8%). One hundred and thirty-two patients (32.6%) were diagnosed in acute care units. Seventy-five percent of patients developed AKI during admission in a non-Renal specialty. Mean baseline eGFR was 50.2 ± 27.7 mL/min. Mean creatinine at AKI diagnosis was 297 ± 161 μmol/L. Renal consultations were initiated at KDIGO Stages 1, 2 and 3 in 58.9, 24.5 and 16.6% of patients, respectively. Three hundred and ten (76.7%) patients had a single etiology of AKI with the 3 most common etiologies of AKI being pre-renal (27.7%), sepsis-associated (25.5%) and ischemic acute tubular necrosis (15.3%). One hundred and nine (27%) patients received acute renal replacement therapy. In-hospital mortality was 20.3%. Six-month mortality post-AKI event was 9.4%. On survival analysis, patients with KDIGO Stage 3 AKI had significantly shorter survival than other stages.

Conclusion

AKI is associated with significant in-hospital to 6-month mortality. This signifies the pressing need for AKI prevention, early detection and intervention in mitigating reversible risk factors in order to optimize clinical outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12882-019-1466-z) contains supplementary material, which is available to authorized users.

Augmented Adsorptive Blood Purification during Continuous Veno-Venous Haemodiafiltration in a Severe Septic, Acute Kidney Injury Patient: Use of oXiris®: A Single Centre Case Report

The use of the oXiris® haemofilter during continuous veno-venous haemodiafiltration (CVVHDF) for acute kidney injury (AKI) and severe sepsis is not completely understood. Although this filter has in vitro adsorptive properties for blood-borne cytokines and other humoural mediators of sepsis, its clinical usefulness is uncertain. Given its inherent adsorptive limitation for septic mediators, we developed a CVVHDF protocol in which the oXiris haemofilter was electively changed every 12 h even though there was no clotting or adverse circuit pressures. Augmented filter membrane adsorption was conducted for 3 consecutive days. We treated a critically ill patient with severe sepsis secondary to a gram-negative bacterial infection and sepsis-associated acute kidney injury (SA- AKI) in this way. The patient required high-dose vasopressor support, required mechanical ventilation, had received 12 h of CVVHDF with conventional M100 haemofilter, was on broad spectrum antibiotics and other conventional intensive care unit (ICU) care, prior to institution of the frequent oXiris haemofilter change protocol. Following the start of elective 12 hourly oXiris filter change, the patient showed reduction in the need for vasopressor and by Day 4 of this SA- AKI frequent filter change protocol, vasopressor requirement ceased, he was extubated. He survived ICU and but not hospital stay. To this end, more clinical studies are needed.

Mutational Signatures in Mandibular Ameloblastoma Correlate with Smoking

Ameloblastoma is a rare tumor of odontogenic epithelium, the low incidence rate of which precludes statistical determination of its molecular characterizations. Despite recent genomic and transcriptomic profiling, the etiology of ameloblastomas remains poorly understood. Risk factors of ameloblastoma development are also largely unknown. Whole exome sequencing was performed on 11 mandibular ameloblastoma samples. We identified 2 convergent mutational signatures in ameloblastoma: 1) a signature found in multiple types of lung cancers with probable etiology of tobacco carcinogens (COSMIC signature 4) and 2) a signature present in gingivobuccal oral squamous cell carcinoma and correlated with tobacco-chewing habits (COSMIC signature 29). These mutational signatures highlight tobacco usage or related mutagens as one possible risk factor of ameloblastoma, since the association of BRAF mutations and smoking was demonstrated in multiple studies. In addition to BRAF hotspot mutations (V600E), we observed clear inter- and intratumor heterogeneities. Interestingly, prior to BRAF mutation, important genes regulating odontogenesis mutated (e.g., corepressor BCOR), possibly playing important roles in tumorigenesis. Furthermore, recurrent mutations in the CDC73 gene, the germline mutations of which predispose patients to the development of jaw tumors, were found in 2 patients, which may lead to recurrence if not targeted by therapeutic drugs. Our unbiased profiling of coding regions of ameloblastoma genomes provides insights to the possible etiology of mandibular ameloblastoma and highlights potential disease risk factors for screening and prevention, especially for Asian patients. Because of the limited sample size and incomplete habitual, dietary, and occupational data, a causal link between tobacco usage and ameloblastoma still requires further investigations.

Platelet Loss across the Hemofilter during Continuous Hemofiltration

BACKGROUND

Thrombocytopenia is a common finding in patients in the intensive care unit receiving continuous renal replacement therapy (CRRT). It is unknown if the hemofilter itself contributes to the platelet loss.

OBJECTIVE

To measure the direct effect of the hemofilter on platelet counts during CRRT.

DESIGN

Prospective, observational study.

SETTING

Intensive care unit of a University hospital.

PATIENTS

Critically ill patients with acute renal failure receiving CRRT.

METHODS

Two samples of blood were drawn simultaneously, pre-filter and post-filter, and analyzed for platelet count. A correction factor was applied to the post-filter platelet count to adjust for the hemoconcentrating effect of net ultrafiltration.

RESULTS

Forty-eight sets of paired data from 22 patients were studied. There was a small but significant decrease in mean platelet count across the hemofilter. The mean platelet count drop was 2.32 x 10(9)/L (s.e. 1.06, p = 0.0487, 95% CI (0.01, 4.62)). Blood flow was strongly related to degree of platelet loss, with a decreased loss of 0.07 x 10(9)/L for every ml/min increase in blood flow (p = 0.015). There was no overall decrease in concurrently measured red cell counts across the hemofilter. However, there was a machine-specific affect on red cell loss (p < 0.0001). The total calculated daily platelet loss across the filter was 625 x 10(9) cells.

CONCLUSION

The hemofilter may contribute to the thrombocytopenia seen during CRRT, by means of either destruction or retention of platelets during passage. This affect appears attenuated by higher blood flows. This information is useful in the assessment of a low platelet count in patients receiving CRRT.

Hypophosphatemia in critically ill patients with acute kidney injury treated with hemodialysis is associated with adverse events

Background. Hypophosphatemia in critically ill patients may be exacerbated by renal replacement therapy (RRT). We aimed to identify risk factors and adverse outcomes associated with hypophosphatemia in intensive care patients treated with RRT for acute kidney injury (AKI).

Methods. This was a secondary analysis of data from a single-center prospective cohort study of medical and surgical intensive care patients with RRT for AKI between 18 December 2010 and 3 April 2013. Demographic, comorbidity, laboratory and RRT data were retrieved from patient case notes and electronic medical records. Outcomes assessed were hypophosphatemia (serum phosphate <0.94 mmol/L) during RRT, intensive care unit (ICU) mortality, and duration of mechanical ventilation and vasopressor support.

Results. Among 96 patients who received acute RRT, 25 (26.0%) developed hypophosphatemia. On multivariate logistic regression, serum phosphate at RRT initiation [adjusted odds ratio (OR) 0.29, 95% confidence interval (CI) (0.09, 0.91), P = 0.03] was independently associated with hypophosphatemia during acute RRT. Patients with hypophosphatemia during RRT required longer ventilatory support [median 12 (interquartile range: 8, 17) days versus 5 (3, 9) days, P < 0.001] and vasopressor support [5 (4, 15) days versus 2 (2, 6) days, P = 0.003] compared with those without hypophosphatemia but there was no significant difference in ICU mortality [5 patients (20.0%) versus 24 patients (33.8%), P = 0.20]. Hypophosphatemia during RRT was independently associated with prolonged mechanical ventilation (≥7 days) [adjusted OR 14.0, 95% CI (1.37, 143.90), P = 0.03].

Conclusion. Hypophosphatemia is common during acute RRT for critically ill patients and was associated with adverse clinical outcomes.

Initiating acute dialysis at earlier Acute Kidney Injury Network stage in critically ill patients without traditional indications does not improve outcome: a prospective cohort study

AIM

Optimal timing for acute renal replacement therapy (ARRT) initiation in critically ill patients with acute kidney injury (AKI) is unclear. We aimed to evaluate outcomes in patients who initiated ARRT for traditional indications versus those who met Acute Kidney Injury Network (AKIN) criteria without traditional indications.

METHODS

This was a single-centre prospective cohort study of medical and surgical intensive care patients with AKI. Traditional indications for ARRT initiation included: serum potassium ≥6.0 mmol/L, serum urea ≥30 mmol/L, arterial pH < 7.25, serum bicarbonate <10 mmol/L, acute pulmonary oedema, acute uraemic encephalopathy or pericarditis. In absence of these indications, ARRT was commenced if patients had (i) AKIN Stage 3 or (ii) AKIN Stage 1 or 2 with 'compelling' conditions. Primary outcomes were intensive care unit (ICU) and in-hospital mortality.

RESULTS

ARRT was initiated in 140 patients: traditional indications in 56 (40%); AKIN Stage 3 without traditional indications in 38 (27%); and AKIN Stage 1 or 2 with 'compelling' conditions in 46 (33%) patients. Traditional indications at ARRT initiation was associated with increased in-hospital mortality (adjusted odds ratio (95% confidence interval), 6.48 (1.54, 27.29)). In absence of traditional indications, earlier ARRT initiation, as defined by those with AKIN Stage 1 or 2, did not decrease ICU deaths (30.0% vs 18.8%, P = 0.30) or in-hospital mortality (50.0% vs 34.2%, P = 0.15) compared with those who were started on ARRT for AKIN Stage 3.

CONCLUSIONS

Presence of traditional indications at ARRT initiation was associated with greater mortality. Initiating dialysis at earlier AKIN stage did not improve survival in patients without traditional indications.

Long-Term Risk of Progressive Chronic Kidney Disease in Patients with Severe Acute Kidney Injury Requiring Dialysis after Coronary Artery Bypass Surgery

AIM

Few studies have evaluated patients after cardiac surgery for subsequent chronic kidney disease (CKD) which increases cardiovascular morbidity and mortality. This study aimed to ascertain the long-term renal outcome in adult patients with severe acute kidney injury (AKI) after coronary artery bypass graft (CABG) surgery.

METHODS

This is a single-center retrospective cohort study of consecutive adult patients who received acute dialysis for AKI after CABG between February 8, 2009 and January 30, 2011. Data on pre- and intra-operative factors were retrieved from electronic medical records. The primary endpoint was CKD progression as defined by dialysis dependence or doubling of serum creatinine from the pre-operative level. Secondary endpoints included in-hospital mortality and renal function at 3 months and 1 year.

RESULTS

Fifty-five patients required acute dialysis after CABG. The median age was 67 years (IQR: 61, 75), and 70.9% were male. Median pre-operative serum creatinine was 157 µmol/l (IQR: 122, 203). A total of 19 patients (34.5%) died. The median follow-up time for hospital survivors was 44.2 months (IQR: 25.0, 49.4) after surgery. Among the 36 survivors, 14 patients (38.9%) reached the primary endpoint. Patients with CKD progression had higher pre-operative serum creatinine [median 214 µmol/l (IQR: 159, 399) vs. 155 µmol/l (112, 187), p = 0.015] and lower eGFR [median 20.4 ml/min/1.73 m(2) (IQR: 11.9, 38.2) vs. 39.9 ml/min/1.73 m(2) (25.9, 55.5), p = 0.027] compared to those who did not have CKD progression.

CONCLUSION

Patients with severe AKI after CABG are at high risk of long-term renal dysfunction and should be monitored regularly for deterioration.

The significance of tubular and glomerular proteinuria in critically ill patients with severe acute kidney injury

OBJECTIVE

Critically ill patients with acute kidney injury (AKI) frequently need acute renal replacement therapy (aRRT). We evaluated an inexpensive, rapid quantitative and qualitative analysis of proteinuria on the course of AKI patients requiring aRRT in intensive care.

METHOD

This was a prospective, observational study of critically ill patients with severe established AKI or Acute on Chronic Kidney Injury (AoCKI) requiring aRRT. Urine samples were analyzed using Sodium-Dodecyl-Sulphate-Polyacryamide Gel Electrophoresis (SDS-PAGE).

RESULTS

A total of 30 critically ill patients were studied. Those who died have higher APACHE II (29 ± 6 vs. 20 ± 5, p<0.001), multi-organ failure (0.7 ± 0.5 vs. 0.2 ± 0.4, p < 0.02) and Tubular/Glomerular ratio (114 ± 60 vs. 75± 37, p < 0.05).The renal non-recoverers have higher baseline creatinine (415 ± 328 vs. 125± 19 umol/l, p < 0.01), urinary Dipstick value (1.8±0.8 vs. 0.5±0, p <0.05) and Glomerular score (3.0 ± 1.8 vs. 0.6 ± 0.2, p < 0.02).Heavy tubular proteinuria also predicts a longer duration of interim dialysis support and mortality whereas glomerular proteinuria correlates with development of chronicity and End Stage Renal Disease (ESRD).

CONCLUSIONS

The dominant presence of tubular proteinuria is associated with poor survival in patients who have high APACHE II score and multi-organ failure. It also correlates with a longer duration of dialysis support in survivals. Renal Non-recoverers had heavy dominant presence of glomerular proteinuria. SDS-PAGE proteinuria analysis offers a reliable and inexpensive method to prognosticate proteinuria in this group of critically ill patients.

Severe hypoglycaemia in type 1 diabetes mellitus: underlying drivers and potential strategies for successful prevention

Hypoglycaemia remains an over-riding factor limiting optimal glycaemic control in type 1 diabetes. Severe hypoglycaemia is prevalent in almost half of those with long-duration diabetes and is one of the most feared diabetes-related complications. In this review, we present an overview of the increasing body of literature seeking to elucidate the underlying pathophysiology of severe hypoglycaemia and the limited evidence behind the strategies employed to prevent episodes. Drivers of severe hypoglycaemia including impaired counter-regulation, hypoglycaemia-associated autonomic failure, psychosocial and behavioural factors and neuroimaging correlates are discussed. Treatment strategies encompassing structured education, insulin analogue regimens, continuous subcutaneous insulin infusion pumps, continuous glucose sensing and beta-cell replacement therapies have been employed, yet there is little randomized controlled trial evidence demonstrating effectiveness of new technologies in reducing severe hypoglycaemia. Optimally designed interventional trials evaluating these existing technologies and using modern methods of teaching patients flexible insulin use within structured education programmes with the specific goal of preventing severe hypoglycaemia are required. Individuals at high risk need to be monitored with meticulous collection of data on awareness, as well as frequency and severity of all hypoglycaemic episodes.

Genomics and Disease Progression in IgA Nephritis

Apart from clinical, histological and biochemical indices, genomics are now being employed to unravel the pathogenetic mechanisms in the disease progression of IgA nephritis (IgAN). The results of angiotensin converting enzyme (ACE) gene polymorphism have been controversial. Those patients with the DD genotype seem to have a poorer prognosis. However, with high dose angiotensin receptor blocker (ARB) therapy, the ACE gene polymorphism status of a patient may no longer be a matter for concern as those with the DD genotype would also respond favourably to high dose ARB therapy. Association studies with gene sequencing and haplotypes have suggested that multiple genes are involved in the pathogenesis of IgAN. Some workers have reported a synergistic effect in the combined analysis of AGT-M235T and ACE I/D polymorphism. With the use of deoxyribo nucleic acid (DNA) microarray, tens of thousands of gene expressions genome-wide can be examined together simultaneously. A locus of familial IgAN has been described with strong evidence of linkage to IgAN1 on chromosome 6q22-23. Two other loci were reported at 4q26-31 and 17q12-22. DNA microarray techniques could also help in the identification of specific pathogenic genes that are up- or down-regulated and this may allow genome wide analyses of these genes and their role in the pathogenesis and progression of IgAN. Recently, using genome-wide association studies (GWAS) more loci for disease susceptibility for IgAN have been identified at 17p13, 8p23, 22q12, 1q32 and 6p21. Key words: Gene sequencing, Haplotypes, Microarray, Single nucleotide polymorphism

Genomics and disease progression in IgA nephritis

Apart from clinical, histological and biochemical indices, genomics are now being employed to unravel the pathogenetic mechanisms in the disease progression of IgA nephritis (IgAN). The results of angiotensin converting enzyme (ACE) gene polymorphism have been controversial. Those patients with the DD genotype seem to have a poorer prognosis. However, with high dose angiotensin receptor blocker (ARB) therapy, the ACE gene polymorphism status of a patient may no longer be a matter for concern as those with the DD genotype would also respond favourably to high dose ARB therapy. Association studies with gene sequencing and haplotypes have suggested that multiple genes are involved in the pathogenesis of IgAN. Some workers have reported a synergistic effect in the combined analysis of AGT-M235T and ACE I/D polymorphism. With the use of deoxyribo nucleic acid (DNA) microarray, tens of thousands of gene expressions genome-wide can be examined together simultaneously. A locus of familial IgAN has been described with strong evidence of linkage to IgAN1 on chromosome 6q22-23. Two other loci were reported at 4q26-31 and 17q12-22. DNA microarray techniques could also help in the identification of specific pathogenic genes that are up- or down-regulated and this may allow genome wide analyses of these genes and their role in the pathogenesis and progression of IgAN. Recently, using genome-wide association studies (GWAS) more loci for disease susceptibility for IgAN have been identified at 17p13, 8p23, 22q12, 1q32 and 6p21.

The impact of hypoglycaemia on patients admitted to hospital with medical emergencies

AIMS

To quantify the frequency of biochemical hypoglycaemia in acutely unwell patients in the medical assessment unit and relate this to their subsequent outcomes.

METHODS

A retrospective audit was conducted on all emergency medical patients attending the medical assessment unit between November 2010 and April 2011. Capillary blood glucose measurements were obtained and electronically stored for all patients. Admission details, presence of diabetes, type of diabetes and treatment, length of stay in hospital and death in hospital were obtained from the hospital clinical coding data and electronic discharge summary. The incidence of hypoglycaemia in patients with and without diabetes was quantified. The mean age, length of stay and percentage of death in hospital were compared between groups with and without hypoglycaemia.

RESULTS

One hundred and thirty-eight (9.5%) patients with diabetes and 70 (2.7%) patients without diabetes had an episode of hypoglycaemia in the medical assessment unit. Patients with diabetes and hypoglycaemia on admission had a significantly longer length of stay (mean ± sd) (10.3 ± 11.2 vs. 7.3 ± 9.5 days, P = 0.001) and higher rate of hospital mortality (14.5 vs. 5.2%, P < 0.001) compared with those without hypoglycaemia. Patients without diabetes with hypoglycaemia had a longer length of stay (mean ± sd) (9.1 ± 10.5 vs. 6.7 ± 9.9 days, P = 0.05) and a higher rate of hospital mortality (24.3 vs. 5.4%, P < 0.001) compared with those without hypoglycaemia.

CONCLUSION

Hypoglycaemia is associated with an increased length of stay in hospital and an increased in-hospital mortality rate. Hypoglycaemia may have contributed to the poorer outcome, but would also appear to be a marker of disease severity in unwell patients, especially patients with sepsis.

National Health Survey on the Prevalence of Urinary Abnormalities in the Population: then and now (1975 to 2012)

Introduction: This paper presents the results of a community survey on urinary abnormalities which covered 1/80th of the population of Singapore in 1975. These findings were compared with the data from the Singapore National Service Registrants in 1974 as well as data from a recent survey in Singapore and that of other Asian and Western countries. Materials and Methods: The study covered 18,000 persons aged 15 years and above, representing a sampling fraction of 1/80th of the population. A total of 16,808 respondents attended the fi eld examination centres, of whom 16,497 had their urine sample tested representing 92.7% of the sample population. Results: In the dipstick urine testing at the fi eld examination centres, 769 subjects (4.6%) were found to have urinary abnormalities. Two hundred and eighty-two (36.7%) of these 769 subjects were found to have urinary abnormalities based on urine microscopy constituting a prevalence of 1.71%. The prevalence of proteinuria was 0.63% and for both haematuria and proteinuria was 0.73%. The prevalence for hypertension was 0.43% and renal insufficiency was 0.1%. Discussion: The consensus is that routine screening for chronic kidney disease (CKD) in the general population is not cost effective as the yield is too low. Whilst, most studies showed that screening of the general population was not cost effective, it has been suggested that screening for targeted groups of subjects could help to identify certain risk groups who may benefit from early intervention to prevent or retard the progression of CKD. Conclusion: The prevalence of urinary abnormalities in Singapore has remained the same, now and three decades ago. Key words: Chronic kidney disease, Proteinuria, Screening

National Health Survey on the prevalence of urinary abnormalities in the population: then and now (1975 to 2012)

INTRODUCTION

This paper presents the results of a community survey on urinary abnormalities which covered 1/80th of the population of Singapore in 1975. These findings were compared with the data from the Singapore National Service Registrants in 1974 as well as data from a recent survey in Singapore and that of other Asian and Western countries.

MATERIALS AND METHODS

The study covered 18,000 persons aged 15 years and above, representing a sampling fraction of 1/80th of the population. A total of 16,808 respondents attended the field examination centres, of whom 16,497 had their urine sample tested representing 92.7% of the sample population.

RESULTS

In the dipstick urine testing at the field examination centres, 769 subjects (4.6%) were found to have urinary abnormalities. Two hundred and eighty-two (36.7%) of these 769 subjects were found to have urinary abnormalities based on urine microscopy constituting a prevalence of 1.71%. The prevalence of proteinuria was 0.63% and for both haematuria and proteinuria was 0.73%. The prevalence for hypertension was 0.43% and renal insufficiency was 0.1%.

DISCUSSION

The consensus is that routine screening for chronic kidney disease (CKD) in the general population is not cost effective as the yield is too low. Whilst, most studies showed that screening of the general population was not cost effective, it has been suggested that screening for targeted groups of subjects could help to identify certain risk groups who may benefit from early intervention to prevent or retard the progression of CKD.

CONCLUSION

The prevalence of urinary abnormalities in Singapore has remained the same, now and three decades ago.

An Introduction to Extracorporeal Blood Purification in Critical Illness

Critical care nephrology is an emerging sub-specialty with rapid technological advancement and a growing body of dedicated literature in blood purification techniques. Their applications have been extended to improve morbidity and survival in multiple organ dysfunctions. Novel techniques have also allowed us to push the frontiers in transplant medicine, giving high-immunological risk patients a chance at a kidney transplant where this was previously precluded by hyperacute antibody-mediated rejection. We aim to review the myriad extracorporeal blood purification techniques now available for treating various critical illnesses in our clinical practice. Some of these techniques will still require further clinical research to determine the optimal timing and dose in order to achieve significant improvement in clinical outcomes.

Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of urinary protein in acute kidney injury

Recent experimental and clinical studies have shown the importance of urinary proteomics in acute kidney injury (AKI). We analyzed the protein in urine of patients with clinical AKI using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) for its diagnostic value, and followed them up for 40 months to evaluate prognosis. Urine from 31 consecutive cases of AKI was analyzed with SDS-PAGE to determine the low, middle and high molecular weight proteins. Fractional excretion of sodium (FENa) was estimated from serum and urine creatinine and sodium (Na). The cases were followed-up for 40 months from the end of the recruitment of study cases. Glomerular protein was higher in the hematuria group when compared with the non-hematuria group (P <0.04) and in the AKI group than in the acute on chronic renal failure (AKI-on-CRF) group (P <0.002). Tubular protein was higher in the AKI-on-CRF group (P <0.003) than in the AKI group. Tubular protein correlated with FENa in groups with diabetes mellitus (DM), AKI-on-CRF, and without hematuria (P <0.03, P <0.02 and P <0.004, respectively). Pattern of protein did not differ between groups with and without DM and clinical acute tubular necrosis (ATN). At the end of 40 months follow-up, category with predominantly glomerular protein progressed to chronic renal failure (CRF) or end-stage renal failure in higher proportion (P <0.05). In clinical AKI, we observed that glomerular protein dominated in cases with glomerular insult, as indicated by hematuria. Tubular protein was common in the study cases with CRF, DM and cases without hematuria. This indicates tubulo-interstitial injury for AKI in these cases. Patients with predominantly glomerular protein had an adverse outcome.

Ministry of health clinical practice guidelines: screening of cardiovascular disease and risk factors

The Ministry of Health (MOH) publishes clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors to provide doctors and patients in Singapore with evidence-based guidance on the screening of cardiovascular disease and risk factors. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Screening of Cardiovascular Disease and Risk Factors, for the information of readers of the Singapore Medical Journal. Page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=25776). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Impact of patterns of proteinuria on renal allograft function and survival: a prospective cohort study

BACKGROUND

Proteinuria is an important complication in renal transplant recipients. The aim of this prospective study was to evaluate the long-term impact of transplant proteinuria patterns on allograft function and survival.

METHODS

We analyzed urinary protein of a cohort of 83 renal transplants with proteinuria ≥0.5 g/d by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and radial immunogel diffusion assay. After initial stratification and analysis, the cohort was followed up for 16 yr. The graft outcome and survival were analyzed using Cox regression model to determine their association with different patterns of initial transplant proteinuria.

RESULTS

Group with predominantly glomerular (middle- and high-molecular-weight with or without low-molecular-weight) proteinuria (61%) had higher serum creatinine (p < 0.001) than the group with predominantly tubular (low-molecular-weight) proteinuria (39%). The incidences of chronic graft dysfunction and graft loss had increased in the glomerular proteinuria group (p < 0.001, hazard ratio 3.6, 95% confidence interval 1.7-7.5 and p < 0.001, hazard ratio 4.9, 95% confidence interval 1.9-12.1, respectively). Patient death did not differ (p = 0.434, hazard ratio 1.5, 95% confidence interval 0.5-4.5).

CONCLUSION

  Proteinuria in renal transplants can be differentiated into glomerular and tubular types based on molecular weight. Glomerular proteinuria is associated with significant increase in graft dysfunction and graft loss.

Rapid aneuploidy screening with fluorescence in-situ hybridisation: is it a sufficiently robust stand-alone test for prenatal diagnosis?

OBJECTIVES

To assess the clinical utility of fluorescence in-situ hybridisation with chromosomes 13, 18, 21, X and Y as a stand-alone test in detecting chromosomal abnormalities, and the types of chromosomal abnormalities missed.

DESIGN

Retrospective analysis.

SETTING

A restructured Government hospital in Singapore and an academic hospital in the United States.

PARTICIPANTS

Cytogenetic data of prenatal specimens and results of fluorescence in-situ hybridisation of 5883 patients performed between January 2000 and August 2007 were reviewed.

RESULTS

Fluorescence in-situ hybridisation detected 558 (9.5%) patients with chromosomal abnormalities. Abnormal ultrasounds (70%) and maternal serum screens (21%) were the most indicative of chromosomal abnormalities. When comparing fluorescence in-situ hybridisation data with karyotype results for the five chromosomes of interest, the sensitivity and specificity were 99.3% and 99.9%, respectively. When comparing fluorescence in-situ hybridisation data with karyotype results for all chromosomes, the sensitivity decreased to 86.8%, whereas the specificity remained at 99.9%. Of 643 cases with karyotype abnormalities, 85 were fluorescence in-situ hybridisation-negative (false negative rate, 13.2%), which included structural rearrangements, chromosome mosaicism, and other trisomies. Despite abnormal ultrasound indications, fluorescence in-situ hybridisation missed 32 cases which included structural rearrangements, mosaicisms, and other trisomies.

CONCLUSION

This study does not support fluorescence in-situ hybridisation as a stand-alone test. Institutions supporting fluorescence in-situ hybridisation as a stand-alone test must seriously consider the risks of a missed diagnosis.

Subglottic stenosis in infants and children

INTRODUCTION

This study aimed to examine the epidemiology and outcome of subglottic stenosis in infants and children, and to evaluate the current techniques used in its diagnosis and management at the KK Women's and Children's Hospital, Singapore.

METHODS

A retrospective review and long-term follow-up was conducted in all infants and children diagnosed with subglottic stenosis between January 1997 and December 2008.

RESULTS

A total of 18 patients (nine male and nine female) with a median age of 7.5 months were identified. Two patients were diagnosed with definite congenital stenosis and 16 patients with acquired stenosis. The majority had Grade I stenosis (55.6 percent), followed by Grade II (27.8 percent) and Grade III (16.7 percent). None had Grade IV stenosis. 17 patients were intubated, and seven underwent tracheostomy. The most common surgical intervention performed was microlaryngoscopy and bronchoscopy with bougie dilation. The other surgical interventions included cricoid split, laryngotracheal reconstruction and cricotracheal resection. As of December 2008, the median duration of treatment was four years, with an overall recovery rate of 66.7 percent. The successful decannulation rate was 57.1 percent. Two mortalities were reported due to reasons unrelated to subglottic stenosis. Two patients were still undergoing treatment at the time of the study, and two were lost to follow-up.

CONCLUSION

Conservative management alone may be required in the majority of Grade I stenosis cases. We observed that the mean number of reconstructive procedures performed per patient increased with the increase in the severity of stenosis. Each laryngeal framework procedure has to be customised to suit the individual.

Electrolyte Mass Balance During CVVH: Lactate vs. Bicarbonate‐Buffered Replacement Fluids

OBJECTIVE

To compare the effect of lactate vs. bicarbonate-buffered replacement fluids on electrolyte mass balance during isovolemic continuous veno-venous hemofiltration (CVVH).

DESIGN

Randomized controlled study with double cross over.

SETTING

Intensive care unit of a tertiary university hospital.

PATIENTS AND PARTICIPANTS

Eight patients with acute renal failure (ARF).

INTERVENTIONS

Isovolemic CVVH (2L/hr of replacement fluid) was performed in random order with either bicarbonate or lactate-buffered replacement fluid delivered pre-filter.

MEASUREMENTS AND RESULTS

Sodium, potassium, chloride, magnesium, and phosphate, were measured in each sample. There was a mass gain of sodium, which was similar under both conditions (bicarbonate: 23.3+/-4.9 mmol/hr, lactate: 22.7+/-3.5 mmol/hr). Mass chloride gains occurred with bicarbonate-buffered replacement fluid only (12.8+/-5.3 mmol/hr), while there was an overall net loss of chloride with lactate fluids (-2.5+/-5.2 mmol/hr), resulting in a significant difference in chloride mass balance (p<0.0001). Magnesium mass balance was negative with bicarbonate buffer only (-0.6+/-0.2 mmol/hr) and also differed significantly from that obtained with lactate fluids (-0.1+/-0.2 mmol/hr, p<0.0001). Phosphate losses (bicarbonate: -1.7+/-0.7 mmol/hr, lactate: -1.7+/-0.5 mmol/hr) were equivalent with both buffers. Potassium mass balance was neutral.

CONCLUSIONS

Mass balance during isovolemic CVVH is significantly affected by the type of replacement fluid administered prefilter. Isovolemic CVVH is not isonatremic and the use of bicarbonate-buffered fluid results in a significant accumulation of chloride and a loss of magnesium.

Quantitative methylation analyses of resection margins predict local recurrences and disease-specific deaths in patients with head and neck squamous cell carcinomas

This study sought to determine whether the presence of hypermethylated genes in the surgical margins can predict local recurrences in head and neck squamous cell carcinomas (HNSCCs). We prospectively collected tumour and surgical margin specimens from patients with HNSCCs who had undergone surgical resections. Quantitative methylation-specific PCR (QMSP) of CDKN2A, CCNA1 and DCC were performed in these specimens and correlated with clinical data. Of the 42 patients eligible for the study, 27 were hypermethylation informative for the above three genes. This latter group was associated with longer disease-free survivals (P=0.007) and longer time to disease-specific deaths (P=0.004). Multivariate analyses confirmed hypermethylation non-informative tumours as an independent prognosticating factor for disease-specific deaths (risk ratio 3.8, P=0.026). Quantitative MSP of the margins of 24 hypermethylation informative tumours revealed that 11 patients had molecularly positive margins, of which, five developed disease-specific events (DSEs, three local recurrences and two metastases), compared to none in patients with molecularly negative margins, after a median follow-up of 48 months. Log-rank analyses showed that molecularly positive margins were associated with shorter time to local recurrences and disease-specific deaths (P=0.03 and 0.01, respectively). This study demonstrated that QMSP of hypermethylated promoters in surgical margins predicted all the local recurrences in our series of HNSCC patients. We have also identified hypermethylation non-informative tumours as an independent predictor for the development of DSEs.

Ultrasonographical features of morbidly-adherent placentas

Morbidly-adherent placentas manifest as placenta accreta, increta or percreta, depending on the depth of placental invasion. These conditions present high risks of severe obstetrical haemorrhage at delivery. The underlying pathology is due to defects in the decidua basalis caused by a variety of insults, such as previous surgery, excessive curettage or infection. The incidence of morbidly-adherent placentas is rising as the frequency of caesarean sections increase. Imaging plays an important role in the antenatal detection of this condition. Based on the case series seen at our local institution, we describe the imaging characteristics of this condition as seen on grayscale ultrasonography, colour/power Doppler ultrasonography, three-dimensional ultrasonography and magnetic resonance imaging.

Anticoagulation Minimization Is Safe and Effective in Albumin Liver Dialysis Using the Molecular Adsorbent Recirculating System

The molecular adsorbent recirculating system (MARS) is a blood purification device with renal and hepatic dialytic effects. This study examined the use of low-dose unfractionated heparin in MARS. This was a prospective, observational study of 15 MARS treatment sessions (mean duration per treatment cycle = 12.2 +/- 4.5 h) in four patients with severe acute decompensation of chronic liver disease (n = 3) and fulminant hepatic failure (n = 1) treated with intermittent MARS. All patients were critically ill (APACHE II 24.8 +/- 3.3). Renal dialysis was with continuous hemofiltration and/or slow low-efficiency dialysis. One MARS session was terminated because of vascular access occlusion (1/15; 6.7%). Bleeding was noted in two sessions (2/15; 13%). Twelve MARS sessions were heparin-free and three treatments were with mean heparin dose of 833 +/- 382 IU. Serum biochemical parameters pre- and post-MARS were total bilirubin (micromol/L): 409.4 +/- 141.6 versus 282.9 +/- 90, P < 0.05; plasma ammonia (micromol/L): 44.3 +/- 21.2 versus 28.8 +/- 20.2, P = 0.002; urea (mmol/L): 15.9 +/- 11.8 versus 7.9 +/- 6.6, P = 0.002; creatinine (micromol/L): 252.4 +/- 151.9 versus 150.1 +/- 96.6, P = 0.003. Pre-MARS versus post-MARS systolic (SBPs) and diastolic (DBPs) blood pressures (mm Hg) were SBP = 129.2 +/- 27.7 versus 124 +/- 25, P = 0.838; and DBP = 60.7 +/- 15.3 versus 56 +/- 13, P = 0.595. Prothrombin time (PT), activated partial thromboplastin time (aPTT) and platelet count (Plt) pre- and post-MARS were PT(s): 22 +/- 7.9 versus 23.8 +/- 10.2, P = 0.116; aPTT (s): 64.5 +/- 40.9 versus 85.5 +/- 50.6, P = 0.092; and Plt (x10(3)/mm(3)): 87 +/- 67.6 versus 68.8 +/- 39, P = 0.098. MARS priming with heparin saline was safe. Heparin-minimized MARS did not compromise circuit function and longevity in extended intermittent MARS.

Use of molecular adsorbent recirculating system in acute liver failure attributable to dengue hemorrhagic fever

Fulminant liver failure is an uncommon but life-threatening complication of severe dengue infection. Molecular adsorbent recirculating system (MARS), which reverses hepatic encephalopathy, is an emerging important element in the armamentarium of organ support in the intensive care unit in patients suffering from acute liver failure. We report an intensive care unit case of fulminant liver failure secondary to dengue hemorrhagic fever, which was supported with MARS. MARS led to rapid reversal of biochemical profile and encephalopathy, resulting in early extubation and intensive care unit discharge.

Toxoplasmic retinochoroiditis presenting in childhood: clinical findings in a UK survey

AIM

To compare the clinical findings in children with symptomatic toxoplasmic ocular lesions attributable to infection acquired before or after birth.

METHODS

Cases were prospectively ascertained for 24 months through national surveillance units and reference laboratories in the British Isles. Age and presenting symptoms, site of lesion and visual impairment in children who were classified as acquiring infection either before or after birth on the basis of clinical and serological findings were compared.

RESULTS

31 children had toxoplasmic retinochoroiditis, 15 had congenital infection and all but three of these presented before the age of 4 years. The remaining 16 children acquired toxoplasmosis postnatally, and 14 of 16 presented after the age of 10 years. A further four children had retinochoroiditis due to other causes. The presence of bilateral, multiple or posterior pole lesions did not distinguish between the two groups, but most children (16/19; 84%) presenting with acute ocular symptoms had postnatally acquired infection. Unilateral visual impairment (Snellen < or =6/18) was equally prevalent in the two groups (4/9 before birth v 7/16 after birth; p>0.5). Only two children had bilateral visual impairment, both of whom had congenital infection. No child was blind.

CONCLUSIONS

About 50% of children with ocular lesions due to toxoplasmosis had postnatal infection. Retinochoroidal lesions due to infection before and after birth were indistinguishable. The prognosis for bilateral visual function was good, regardless of when infection was acquired.

Intrapartum maternal sinus bradycardia with spontaneous resolution following delivery

Pregnancy is a normal physiological state that is characterised by significant adaptive changes, many of which take place in the cardiovascular system. These adaptations are believed to be the cause for the increased incidence in cardiac arrhythmias in pregnancy and particularly, in labour. We report an unusual case of a healthy 32-year-old primigravida who developed profound intrapartum bradycardia which persisted throughout labour. Spontaneous recovery to pre-labour baseline heart rate occurred following spontaneous vaginal delivery. Maternal and foetal statuses remained satisfactory during labour. This case report underscores the importance of recognising that arrhythmias in various forms are common in labour. In the absence of detectable underlying cardiac disease or maternal and foetal compromise, continuation of the labour with a view to vaginal delivery should be the goal.

Symptomatic toxoplasma infection due to congenital and postnatally acquired infection

AIMS

To determine the incidence and severity of symptomatic toxoplasma infection presenting during childhood due to congenital or postnatally acquired infection.

METHODS

Between 2002 and 2004, newly diagnosed children (<16 years) with signs or symptoms of congenital or ocular toxoplasmosis were reported by clinicians to the British Paediatric and Ophthalmic Surveillance Units or by toxoplasma referral laboratories. Confirmed cases were estimated to have a greater than 50% probability of congenital and/or ocular toxoplasmosis, based on clinical and serological findings.

RESULTS

Thirty eight children had confirmed toxoplasma infection. Twenty two (58%) were classified with congenital infection (cumulative incidence for England and Wales 1.62[corrected]/100,000 live births; 95% CI 0.85[corrected] to 2.83[corrected]), of whom 2 (9%) were stillborn, 7 (32%) live births had intracranial abnormalities and/or developmental delay (5 of whom had retinochoroiditis), and 10 (45%) had retinochoroiditis with no other abnormalities reported. A further 16 (42%) children were classified as infected after birth; all had retinochoroiditis.

CONCLUSIONS

The low burden of symptomatic congenital toxoplasmosis combined with the lack of evidence of an effective treatment support current policy not to offer prenatal or neonatal screening for toxoplasma infection. Primary prevention strategies need to address acquisition of infection in childhood which accounts for half the ocular disease due to toxoplasma infection in children in the UK and Ireland.

Tocolytic treatment for the management of preterm labour: a systematic review

Spontaneous preterm labour and delivery accounts for approximately one-third of preterm births, which is the predominant cause of perinatal mortality and morbidity. This review aims to evaluate the evidence on the benefits and harms of five classes of tocolytic therapy, namely: betamimetics, calcium channel blockers, magnesium, non-steroidal anti-inflammatory agents, and atosiban. We performed a systematic review of the effectiveness of tocolytics to stop uterine contractions (first-line therapy). Reports of randomised controlled trials from searches of MEDLINE, bibliographies of review articles, Cochrane Collaboration and its Pregnancy and Childbirth Review Group between 1966 and 2003 were identified, using the search terms "randomised controlled trial" (RCT), "preterm labor", "tocolysis", "betamimetics", "ritodrine", "prostaglandin synthetase inhibitors", "indomethacin", "calcium channel blockers", "nifedipine", "oxytocin receptor blockers", "atosiban", and "magnesium sulphate". Studies on women with preterm labour comparing the effects of a tocolytic with a placebo or no treatment that met our inclusion criteria, were included. To our knowledge, the trials were conducted mainly before 1999 and there were no placebo-controlled trials after that. Of the 86 articles identified and evaluated, 14 first-line studies met more stringent requirements for meta-analyses. Tocolytics were associated with significant decreases in the odds of delivery within 24 hours (odds-ratio [OR] 0.54, 95 percent confidence interval [CI] 0.32-0.91) and 48 hours (OR 0.47, 95 percent CI 0.30-0.75). These effects were significant for beta-agonists, atosiban and indomethacin, but not magnesium sulphate. Maternal side-effects significantly associated with betamimetics were pulmonary oedema, cardiac arrhthymias and hypokalaemia. Although calcium antagonists have not been evaluated against placebo, comparative trials with beta-agonists have shown more favourable neonatal outcomes and better prolongation of gestation. In conclusion, the management of threatened preterm labour with first-line tocolytic therapy can prolong gestation. However, the time gained in-utero need to be optimised. There is no clear first-line tocolytic agent. The use of tocolytic agents should be individualised and based on maternal condition, potential side-effects and gestational age.

Plasma filtration

Therapeutic plasma exchange (TPE) or plasmapheresis involves the separation of plasma from whole blood. In so doing, plasma-borne humoral disease mediators are removed from the body. This can attenuate the course and severity of the underlying disease. Diseases that can be treated with TPE are classified into the following categories: (1) endocrinological, (2) neurological, (3) renal/rheumatological, and (4) haematological. TPE is adjuvant in most of these settings. Disease-specific pharmacological treatment remains the cornerstone of treatment in many of these conditions. Plasma separation can be achieved with either (1) centrifugation (CF) or (2) membrane plasma filtration (PF). The latter is the focus of this review. It can be performed using either a continuous renal replacement therapy (CRRT) or haemodialysis (HD) machine. Standard plasma filtration has also been modified to incorporate sorbent technology which obviates the need for plasma volume replacement fluids. Larger clinical issues such as timing of initiation and intensity of therapy are examined.

Determinants of response to a parent questionnaire about development and behaviour in 3 year olds: European multicentre study of congenital toxoplasmosis

BACKGROUND

We aimed to determine how response to a parent-completed postal questionnaire measuring development, behaviour, impairment, and parental concerns and anxiety, varies in different European centres.

METHODS

Prospective cohort study of 3 year old children, with and without congenital toxoplasmosis, who were identified by prenatal or neonatal screening for toxoplasmosis in 11 centres in 7 countries. Parents were mailed a questionnaire that comprised all or part of existing validated tools. We determined the effect of characteristics of the centre and child on response, age at questionnaire completion, and response to child drawing tasks.

RESULTS

The questionnaire took 21 minutes to complete on average. 67% (714/1058) of parents responded. Few parents (60/1058) refused to participate. The strongest determinants of response were the score for organisational attributes of the study centre (such as direct involvement in follow up and access to an address register), and infection with congenital toxoplasmosis. Age at completion was associated with study centre, presence of neurological abnormalities in early infancy, and duration of prenatal treatment. Completion rates for individual questions exceeded 92% except for child completed drawings of a man (70%), which were completed more by girls, older children, and in certain centres.

CONCLUSION

Differences in response across European centres were predominantly related to the organisation of follow up and access to correct addresses. The questionnaire was acceptable in all six countries and offers a low cost tool for assessing development, behaviour, and parental concerns and anxiety, in multinational studies.

Molecular adsorbent recirculating system (MARS)

INTRODUCTION

Molecular adsorbent recirculating system (MARS) for albumin liver dialysis has been used as a bridge to liver transplantation in patients with fulminant hepatic failure (FHF). This review examines the available data on its clinical use, its technical aspects and present gaps in knowledge.

METHODS

Peer-reviewed journals and monographs on the subject were covered.

RESULTS

FHF is associated with elevation in various substances including bilirubin, ammonia, lactate, free fatty acids and aromatic amino acids. Some of these toxic metabolites, such as ammonia and bilirubin, are believed to be central to the clinical manifestations of hepatic encephalopathy and acute renal failure. MARS ameliorates both biochemical and clinical manifestations of FHF by removing both water-soluble and protein-bound toxins. Among the benefits of MARS is the attenuation of severe cerebral oedema and raised intracranial pressure found in FHF, possibly through reduction in high concentrations of these toxins. Although MARS has been shown to be useful in FHF, its clinical efficacy in subfulminant hepatic failure and less severe forms of acute liver failure (ALF) remains uncertain. The current literature also suggests that it may be beneficial to treat cases of acute-on-chronic liver failure (AoCLF). Deranged systemic chemistries can be similarly ameliorated, but the impact of MARS on the natural history of AoCLF remains uncertain. The difficulty lies in being able to accurately quantify residual liver function and variability in the course of acute intercurrent events. The broader question is whether MARS can favourably change the natural history of ALF and FHF. For this, large multi-centre, randomised controlled trials are needed. Furthermore, it is also uncertain how hepatic excretory-assist devices, such as MARS, compare with bio-artificial liver-assist devices which have both synthetic and excretory hepatic functions in ALF treatment in intensive care unit patients. Nevertheless, MARS has proven to be a valuable homeostatic tool that may be useful in restoring the biochemical and clinical status quo in much the same way that continuous veno-venous haemofiltration and mechanical ventilation provide temporary artificial organ support while these organs are in distress. This is the evolving concept of multi-organ support therapy. Other major unresolved issues with MARS include the timing of initiation of albumin liver dialysis, the clinical and/or biochemical parameters to base this decision on, the intensity of MARS therapy (continuous versus intermittent) and the saturation capacity of the system for different metabolites in intermittent MARS.

CONCLUSIONS

MARS is an effective and, thus far, safe homeostatic tool in treating FHF. More studies are needed to delineate its role as a homeostatic tool in less severe forms of ALF, including that which occurs in multi-organ failure and in AoCLF. Other studies need to focus on the optimal timing of initiation of and intensity of MARS albumin liver dialysis. The larger issue is to compare MARS with bio-assist liver devices in treating the whole spectrum of ALF.

MARS therapy in critically ill patients with advanced malignancy: a clinical and technical report

BACKGROUND/METHODS

Molecular Adsorbent Recirculating System (MARS) was used in three consecutive critically ill patients at the Singapore General Hospital with advanced malignancy and acute liver failure (ALF). Case 1 was a male patient with hepatocellular carcinoma (HCC) for which initial right hepatectomy was followed by left hepatectomy 5 months later for recurrent HCC. The postoperative course following second surgery was complicated by severe methicillin-resistant Staphylococcus aureus (MRSA) sepsis, mild azotaemia and subacute cholestatic liver failure. MARS was used thrice in this patient. Case 2 was a female patient with advanced acute lymphoblastic leukaemia (ALL) with post bone marrow transplantation (BMT) acute haemolytic-uraemic syndrome (HUS) secondary to cyclosporin A (Cy A), cytomegalovirus (CMV) infection, severe nosocomial pneumonia, acute renal failure (ARF) treated with continuous haemofiltration and acute veno-occlusive disease resulting in Budd-Chiari syndrome. The latter precipitated ALF. MARS was instituted twice. Case 3 was a male patient with advanced, refractory Hodgkin's disease previously treated with multiple courses of chemotherapy. ALF developed secondary to acute viral hepatitis B flare. He was given a trial of MARS once in the ICU. All the three patients eventually died.

RESULTS

Mean MARS intradialytic systemic pressures were as follows: systolic pressure range was 95 +/- 17 to 128 +/- 17 mmHg and diastolic pressure range was 51 +/- 5 to 67 +/- 7 mmHg. Pressure at albumin dialysate exit point from dialyser 1 (Ae) ranged from 253 +/- 11 to 339 +/- 15 mmHg and that at albumin dialysate entry point into dialyser 1 (Aa) ranged from 142 +/- 11 to 210 +/- 6 mmHg. Ultrafiltration (UF) was 633 +/- 622 mL over mean treatment duration of 6.3 +/- 0.9 h with a total heparin dose of 1583 +/- 817 IU. Coagulation status pre- and 6-h post-MARS was similar: aPTT (P=0.116) and platelet count (P=0.753). There were no bleeding complications or circuit thromboses. MARS had a significant de-uraemization effect (pre- and post-MARS serum creatinine and urea: P=0.046 and 0.028, respectively) but did not significantly attenuate blood lactate, ammonia or total bilirubin levels. Albumin dialysate (Ae - Aa) urea and creatinine concentrations appeared to be sharply attenuated after 6 h of MARS. In contrast, the removal of total bilirubin by albumin dialysate from the blood compartment appeared to plateau after 4 h of continuous MARS operation.

CONCLUSIONS

MARS was well-tolerated in critically ill patients with advanced and complicated cancer. Low-dose heparin was safe and did not compromise MARS circuit integrity. Although MARS had a significant de-uraemization effect, this appeared to be limited by the duration of MARS operation. Our data suggested that such a limit was reached earlier for total bilirubin. More data are needed to confirm the present findings and further delineate the saturation limit of MARS for different toxins that accumulate in ALF. This would affect the optimal duration of MARS therapy.

Audit of 'crash' emergency caesarean sections due to cord prolapse in terms of response time and perinatal outcome

OBJECTIVE

The objective was to audit 'crash' emergency caesarean sections (CS) with respect to response time (the diagnosis to delivery interval [DDI]) and perinatal outcome.

MATERIALS AND METHODS

The computerised database at the Singapore General Hospital (SGH) delivery suite was used to identify all cases of 'crash' emergency CS activated for the diagnosis of cord prolapse from 1992 to 2002. Patients' case notes and neonatal charts were reviewed and the following variables were evaluated: parity, gestational age at the time of delivery and the DDI. Neonatal outcome was measured by Apgar scores at 1 and 5 minutes, cord pH and admission to the neonatal intensive care unit (NICU).

RESULTS

A total of 34 cases of umbilical cord prolapse were identified from 29,867 deliveries, giving an incidence of 0.11% (1 in 900). The median gestational age was 38.5 weeks (range, 25 to 41 weeks). The median time from diagnosis to delivery was 20 minutes (range, 10 to 40 minutes). Seventy-six percent (19/30) were delivered within 30 minutes. The time of diagnosis was not recorded for 5 cases. Sixty-three percent of neonates had an Apgar score < or = 7 at 1 minute of life, increasing to 97% at 5 minutes. There were 3 NICU admissions for reasons of prematurity. There was no perinatal mortality. Cord pH was not performed for 47% of (14/30) neonates. Among the remaining 16 neonates, an umbilical cord pH of < or = 7.20 was found in 62% (10/16). There was poor correlation between the DDI and umbilical cord pH.

CONCLUSION

Three-quarters of our 'crash' emergency CS for cord prolapse were performed within 30 minutes with a good perinatal outcome. However, we have identified areas for improvement to optimise further the operational efficiency of 'crash' emergency CS.

The acid-base effects of continuous hemofiltration with lactate or bicarbonate buffered replacement fluids

OBJECTIVE

To evaluate, quantify and compare the effects of continuous veno-venous hemofiltration (CVVH) with lactate or bicarbonate-buffered replacement fluids on acid-base balance.

DESIGN

Randomized double crossover study.

SETTING

Intensive Care Unit of Tertiary Medical Center.

PARTICIPANTS

Eight patients with severe acute renal failure.

INTERVENTIONS

Random allocation to either 2 hours of isovolemic lactate-buffered (treatment A) CVVH or 2 hours of bicarbonate-buffered (treatment B) CVVH with cross over and with same procedure repeated the following day (double cross over).

MEASUREMENTS AND RESULTS

Timed collections of arterial blood and ultrafiltrate (UF), measurement of blood and UF gases and lactate concentrations and calculation of buffer-base mass balance. At baseline, both groups of patients had a similar, slight metabolic alkalosis (pH: 7.45 vs. 7.45; BE 3.9 mEq/L for treatment A and 4.0 for treatment B) and a serum bicarbonate of 28.1 mmol/L for treatment A vs. 28.3 mmol/L for treatment B; all NS. This alkalosis was present despite slight hyperlactatemia in both groups (A: 2.4 mmol/L vs. B 2.8 mmol/; NS). Within 60 minutes of treatment, however, treatment A led to a significantly higher lactate concentration (3.9 vs 2.5 mmol/L; p = 0.0011), a significantly lower BE (2.3 vs 4.1 mEq/L; p = 0.0019) and a significantly lower bicarbonate concentration (26.7 vs. 28.3 mmol/L; p = 0.0038) in the presence of an unchanged PaCO2. These differences persisted during the study period. The UF of patients receiving treatment A contained more lactate (10.2 vs 2.9 mmol/L; p < 0.0001) and less bicarbonate (25.6 vs. 30.8 mmol/L; p < 0.0001) than treatment B resulting in a mean buffer-base balance of +20.4 mEq/h compared to -2.6 mEq/h for treatment B; p < 0.0001).

CONCLUSIONS

CVVH with lactate-buffered replacement fluids induces iatrogenic hyperlactatemia. Such hyperlactatemia is associated with an acidifying effect despite a positive buffer-base balance.