O45: DEFINING CELL-ENRICHED MICRORNAS TO SUPPORT RATIONAL BIOMARKER SELECTION IN HUMAN RENAL TRANSPLANTATION

Introduction

MicroRNAs are promising biomarkers of renal disease, however the cellular origin of their expression is usually unclear limiting their interpretation when measured in renal biopsies and urine. We hypothesised that by first defining renal cell-enriched microRNAs, we could select biomarkers based on the expected histopathological profile.

Method

Small RNA-sequencing of cortical, proximal tubular (LTL), macrophage (F480), endothelial (CD31) and fibroblast (PDGFRb) populations from the reversible unilateral ureteric obstruction (rUUO) murine model was performed. Hierarchical clustering was used to identify clusters. Findings were translated into an ischaemia reperfusion injury (IRI) model and then into urine samples from renal transplant recipients (n=16) with delayed graft function (DGF) vs. those with primary function.

Result

Kidney injury resulted in significant macrophage infiltration and tubular injury which improved upon reversal. We characterised novel microRNA clusters enriched for each cell type. With injury there was a significant increase in macrophage (p<0.0001), fibroblast (p<0.01) and decrease in proximal tubule (p<0.0001) enriched microRNAs vs. non-enriched microRNAs. We validated macrophage enriched miR-18a, miR-16 and tubular enriched miR-194 in the IRI model, demonstrating that microRNA expression reflected the histological profile. In humans, urinary miR-16 (FC 16.9; p<0.05) and miR-18a (FC 10: p=0.06) were upregulated at day 2 in patients with DGF; outperforming the traditional injury marker KIM1.

Conclusion

This is the first study to characterise cell-enriched microRNAs during renal injury and repair. By defining the source of microRNA expression we were able to rationally select miR-16 and miR-18a as promising urinary biomarkers of renal injury.

Take-home message

We have found that microRNAs have differences in expression between cell types and renal injury states which is important when considering microRNA expression in samples composed of varying cellular composition. By defining the cellular origins of microRNA expression we were able to rationally select microRNA biomarkers of human renal injury.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

BACKGROUND

The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications.

METHODS

ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery.

RESULTS

The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784.

CONCLUSIONS

This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance.

CLINICAL TRIAL REGISTRATION

NCT03044899.

Optimising perioperative care for hip and knee arthroplasty in South Africa: a Delphi consensus study

Background

A structured approach to perioperative patient management based on an enhanced recovery pathway protocol facilitates early recovery and reduces morbidity in high income countries. However, in low- and middle-income countries (LMICs), the feasibility of implementing enhanced recovery pathways and its influence on patient outcomes is scarcely investigated. To inform similar practice in LMICs for total hip and knee arthroplasty, it is necessary to identify potential factors for inclusion in such a programme, appropriate for LMICs.

Methods

Applying a Delphi method, 33 stakeholders (13 arthroplasty surgeons, 12 anaesthetists and 8 physiotherapists) from 10 state hospitals representing 4 South African provinces identified and prioritised i) risk factors associated with poor outcomes, ii) perioperative interventions to improve outcomes and iii) patient and clinical outcomes necessary to benchmark practice for patients scheduled for primary elective unilateral total hip and knee arthroplasty.

Results

Thirty of the thirty-three stakeholders completed the 3 months Delphi study. The first round yielded i) 36 suggestions to preoperative risk factors, ii) 14 (preoperative), 18 (intraoperative) and 23 (postoperative) suggestions to best practices for perioperative interventions to improve outcomes and iii) 25 suggestions to important postsurgical outcomes. These items were prioritised by the group in the consecutive rounds and consensus was reached for the top ten priorities for each category.

Conclusion

The consensus derived risk factors, perioperative interventions and important outcomes will inform the development of a structured, perioperative multidisciplinary enhanced patient care protocol for total hip and knee arthroplasty. It is anticipated that this study will provide the construct necessary for developing pragmatic enhanced care pathways aimed at improving patient outcomes after arthroplasty in LMICs.

First characterization of immunogenic conjugates of Vi negative Salmonella Typhi O-specific polysaccharides with rEPA protein for vaccine development

Efficacious typhoid vaccines for young children will significantly reduce the disease burden in developing world. The Vi polysaccharide based conjugate vaccines (Vi-rEPA) against Salmonella Typhi Vi positive strains has shown high efficacy but may be ineffective against Vi negative S. Typhi. In this study, for the first time, we report the synthesis and evaluation of polysaccharide-protein conjugates of Vi negative S. Typhi as potential vaccine candidates. Four different conjugates were synthesized using recombinant exoprotein A of Pseudomonas aeruginosa (rEPA) and human serum albumin (HSA) as the carrier proteins, using either direct reductive amination or an intermediate linker molecule, adipic acid dihydrazide (ADH). Upon injection into mice, a significantly higher antibody titer was observed in mice administrated with conjugate-1 (OSP-HSA) (P=0.0001) and conjugate 2 (OSP-rEPA) (P≤0.0001) as compared to OSP alone. In contrast, the antibody titer elicited by conjugate 3 (OSPADH-HSA) and conjugate 4 (OSPADH-rEPA) were insignificant (P=0.1684 and P=0.3794, respectively). We conclude that reductive amination is the superior method to prepare the S. Typhi OSP glycoconjugate. Moreover, rEPA was a better carrier protein than HSA. Thus OSP-rEPA conjugate seems to be efficacious typhoid vaccines candidate, it may be evaluated further and recommended for the clinical trials.

Decreased Npas4 and Arc mRNA Levels in the Hippocampus of Aged Memory-Impaired Wild-Type But Not Memory Preserved 11β-HSD1 Deficient Mice

Mice deficient in the glucocorticoid-regenerating enzyme 11β-HSD1 resist age-related spatial memory impairment. To investigate the mechanisms and pathways involved, we used microarrays to identify differentially expressed hippocampal genes that associate with cognitive ageing and 11β-HSD1. Aged wild-type mice were separated into memory-impaired and unimpaired relative to young controls according to their performance in the Y-maze. All individual aged 11β-HSD1-deficient mice showed intact spatial memory. The majority of differentially expressed hippocampal genes were increased with ageing (e.g. immune/inflammatory response genes) with no genotype differences. However, the neuronal-specific transcription factor, Npas4, and immediate early gene, Arc, were reduced (relative to young) in the hippocampus of memory-impaired but not unimpaired aged wild-type or aged 11β-HSD1-deficient mice. A quantitative reverse transcriptase-polymerase chain reaction and in situ hybridisation confirmed reduced Npas4 and Arc mRNA expression in memory-impaired aged wild-type mice. These findings suggest that 11β-HSD1 may contribute to the decline in Npas4 and Arc mRNA levels associated with memory impairment during ageing, and that decreased activity of synaptic plasticity pathways involving Npas4 and Arc may, in part, underlie the memory deficits seen in cognitively-impaired aged wild-type mice.

Activated Protein C does not Improve Mortality in Septic Shock

Compared with placebo, Drotecogin alpha (activated) offers no mortality benefit at either 28 or 90 days in critically ill adults with septic shock.

Level of evidence: 1B (well designed RCT)

Early Neuromuscular Blockade in Severe ARDS

This underpowered study suggests that there may be a mortality benefit in early neuromuscular blockade in severe ARDS.

Level of evidence: 1− (RCT high risk of bias).

Working alongside nursing staff to review medication in nursing homes

Focal points

How do ward pharmacists spend their time?: An activity sampling study

A regular clinical pharmacy service to wards is well established in Britain, yet there has been little practice research in this area. In this study, we established how pharmacists distribute their time between different activities on all the wards. All 28 pharmacists in two London hospitals were observed. The observer recorded their activities at one minute intervals and categorised the activity. Thirty-three hours and five minutes of observations were made. The pharmacists visited a total of 55 wards, and checked 982 drug charts.

The major activities were prescription monitoring, which accounted for 31 per cent ± 2 per cent, of the time (mean of pooled data ± 95 per cent confidence intervals), travel to wards 21 per cent ± 2 per cent, stock control 12 per cent ± 1 per cent, transcription 8 per cent ± 1 per cent and clinical monitoring (such as checking giving sets) 7 per cent ± 1 per cent.

The proportion of time spent on each activity was very similar between the two sites, except for the category “transcription”, which took 11 per cent ± 2 per cent of the time in one hospital, where all discharge prescriptions were transcribed onto ward pharmacy sheets (allowing processing in the pharmacy without the need for drug charts to leave the ward), and 3 per cent ± 1 per cent at the other site, in which they were not transcribed.

These results demonstrate that, when on the ward, pharmacists spend the majority of their time in a clinical role. The methodology is simple to use and appears reproducible. This work, if repeated locally, could be used to highlight areas of inefficiency, and could be used to test and predict the impact of other methods of delivery of clinical pharmacy.

Costing inpatient drug treatment

The aim of this study was to examine costs of charted drugs by using three data capture techniques. Data were manually extracted retrospectively from drug charts for a stratified sample of 200 inpatient stays at each of two London hospitals — a teaching hospital (St George's) and a district general hospital (Kingston). Specialties where costing was not feasible were excluded. These were: intensive care, oncology, dermatology and paediatrics. Three costs were calculated: nonstock drugs administered (the capability of traditional pharmacy computer systems), drugs prescribed (the data captured by a basic computerised prescribing system) and drugs administered (the data captured by a drug administration recording system). Pharmaceuticals not prescribed on the drug chart, such as anaesthetics, contrast media and disinfectants, were not included.

At St George's 2,739 and at Kingston 2,843 prescription entries were recorded, amounting to costs of £2,940 and £2,327, respectively, for drugs administered. A range of £0.01 to £171 per patient (median £4.67) at St George's and £0.00 to £122.66 (median £2.88) at Kingston demonstrates a skewed distribution, with most patients incurring low costs. Non-stock drugs accounted for 21 per cent of the cost of drugs administered at St George's and 15 per cent at Kingston. Twenty-four patients incurred costs above £50, their non-stock drugs being a mean of 21 per cent of their total costs. The cost of drugs administered at both hospitals was found to be 95 per cent of the cost of drugs prescribed.

Computerised prescribing and drug administration recording systems would significantly improve cost allocation. However, it is unlikely that the expense could be justified on the basis of the low value of drugs received by most patients.

Encoding instructions and stimulus presentation in local environmental context-dependent memory studies

Murnane and Phelps (1993) recommend word pair presentations in local environmental context (EC) studies to prevent associations being formed between successively presented items and their ECs and a consequent reduction in the EC effect. Two experiments were conducted to assess the veracity of this assumption. In Experiment 1, participants memorised single words or word pairs, or categorised them as natural or man made. Their free recall protocols were examined to assess any associations established between successively presented items. Fewest associations were observed when the item-specific encoding task (i.e., natural or man made categorisation of word referents) was applied to single words. These findings were examined further in Experiment 2, where the influence of encoding instructions and stimulus presentation on local EC dependent recognition memory was examined. Consistent with recognition dual-process signal detection model predictions and findings (e.g., Macken, 2002; Parks & Yonelinas, 2008), recollection sensitivity, but not familiarity sensitivity, was found to be local EC dependent. However, local EC dependent recognition was observed only after item-specific encoding instructions, irrespective of stimulus presentation. These findings and the existing literature suggest that the use of single word presentations and item-specific encoding enhances local EC dependent recognition.

Extracorporeal Membrane Oxygenation for Severe Respiratory Failure

Management of severe respiratory failure in a specialist centre which is capable of delivering a complex ‘bundle’ of care including a strict acute respiratory distress syndrome (ARDS) protocol, extracorporeal membrane oxygenation (ECMO), molecular adsorbent recycling system (MARS) and steroids, may improve outcomes when compared with conventional care. It is difficult to comment on the value of ECMO alone based on this study.

Level of evidence: 1+ (RCT with a low risk of bias)

Ketamine as an Alternative to Etomidate in the Pre-Hospital Setting

Ketamine is a safe alternative to etomidate for emergency intubation and is associated with significantly less adrenal insufficiency.

Level of evidence: 1+ (RCT with a low risk of bias)

Silver-Coated Endotracheal Tubes and the Incidence of Ventilator-Associated Pneumonia

The use of silver coated endotracheal (ET) tubes leads to statistically significant reduction in ventilator associated pneumonia (VAP) during the first 10 days of intubation. However methodological flaws lead to doubts over the clinical validity of this result.

Level of evidence: 1− (RCT with a high risk of bias)

Low dose Vasopressin in Septic Shock

The addition of low-dose vasopressin to the treatment of septic shock does not reduce mortality compared to the use of norepinephrine alone, but allows a rapid reduction in norepinephrine requirements.

Level of evidence: 1+ (RCT with a very low risk of bias)

Setting PEEP in ALI/ARDS

Compared to a low tidal volume/low PEEP strategy, a low tidal volume/fixed plateau pressure/higher PEEP strategy offers no mortality benefit but may be associated with reduced morbidity.

Level of evidence: 1+ (RCT with a low risk of bias)

A Protocol Mandating a Daily Interruption of Sedatives and Spontaneous Breathing Trial Improves Patient Outcome

In critically ill, mechanically ventilated, non-surgical patients, a protocol pairing daily mandatory sedation breaks (spontaneous awakening trials – SAT) with spontaneous breathing trials (SBT) results in earlier extubation, shorter ICU stay, shorter hospital stay and lower mortality at one year (NNT=7) compared to standard care.

Level of evidence: 1++ (RCT with a low risk of bias)

Low Dose Epoetin Alfa in Critically Ill Patients

Use of low dose epoetin alfa in the critically ill does not reduce the number of patients requiring blood transfusion, or units of red blood cells transfused. There may be a mortality benefit in trauma patients. Epoetin alfa is associated with an increased risk of thrombotic events.

Level of evidence: 1++ (RCT with a very low risk of bias)

The Effect of Obesity on Intensive Care Morbidity and Mortality

Obesity is not demonstrated to be associated with a higher ICU mortality. Obese patients have an increased morbidity on the ICU as evidenced by prolonged requirement for mechanical ventilation and intensive care admission length.

Level of evidence: 1+ (Meta-analysis with a low risk of bias)

Intensive Insulin Therapy and Pentastarch Resuscitation in Severe Sepsis

Neither intensive insulin therapy nor the use of pentastarch as the resuscitation fluid reduces 28-day mortality or morbidity from severe sepsis. Intensive insulin therapy may cause harm because of increased hypoglycaemic episodes. Use of pentastarch increases the need for renal replacement therapy.

Level of evidence: 1+ (RCT with a low risk of bias)

Hydrocortisone Therapy for Patients with Septic Shock

In patients with septic shock, the administration of corticosteroids leads to faster resolution of shock but has no effect on mortality at 28 days or at one year.

Level of evidence: 1+ (RCT with a low risk of bias)

Erythromycin is More Effective than Metoclopramide in the Treatment of Feed Intolerance in Critical Illness

In intensive care patients with feed intolerance, erythromycin reduces gastric residual volume more effectively than metoclopramide (NNT 4). Both drugs rapidly become ineffective. In patients who fail monotherapy, an open-label, non-controlled extension of this study suggests combination therapy may be effective.

Level of evidence: 1+ (RCT with a low risk of bias)

Evidence-Based Intensive Care-The Scottish Medium

Oh no not another article about evidence-based medicine (EBM)! Half of you are thinking ‘it's marvellous and tells you exactly the best way of managing your patients’. The other half if you have read this far will be thinking ‘not more EBM — yet again it's someone trying to replace common sense and experience’.

Computer education. Don't forget the older GPs

OBJECTIVE

To implement and evaluate a computer education and support program for GPs.

METHODS

A 'hands-on' curriculum, based on small group learning in a clinical computing laboratory and supported via the Internet, was developed and implemented. Evaluation was threefold: observations during lessons; interviews; and participants completing a questionnaire before and six months after the course. A randomly selected group of GPs from the same region completed a modified version of the 'before' questionnaire at the same time as participating GPs were completing their six month questionnaire. Participants included 128 GPs in a computer education program in Victoria (Australia) plus 127 'control' GPs. Outcome measures were self reported computing skill, attitudes to and actual use of clinical applications.

RESULTS

Six months after training, there was a significant increase in self reported computer skill (p < 0.01). Multivariate regression found that, after controlling for gender, practice characteristics, and previous training, the older (> 55 years) GPs reported greater change in their skills than their younger colleagues. The increased skill happened regardless of which or how many modules were completed, and included use of email, the Internet, computers for research and electronic prescribing. Awareness of relevant computer applications, confidence with computers and intention to use applications also increased. Participants found the dedicated clinical computing laboratory useful; however, there are significant issues with maintenance and keeping systems up-to-date.

CONCLUSIONS

The computer education and support program was relevant to GP needs, deliverable and effective in improving skills and utilisation. Divisions and other GP organisations should be assisted to establish similar education and support programs and, perhaps, target older doctors.