Predicting time to asystole following withdrawal of life-sustaining treatment: a systematic review

The planned withdrawal of life-sustaining treatment is a common practice in the intensive care unit for patients where ongoing organ support is recognised to be futile. Predicting the time to asystole following withdrawal of life-sustaining treatment is crucial for setting expectations, resource utilisation and identifying patients suitable for organ donation after circulatory death. This systematic review evaluates the literature for variables associated with, and predictive models for, time to asystole in patients managed on intensive care units. We conducted a comprehensive structured search of the MEDLINE and Embase databases. Studies evaluating patients managed on adult intensive care units undergoing withdrawal of life-sustaining treatment with recorded time to asystole were included. Data extraction and PROBAST quality assessment were performed and a narrative summary of the literature was provided. Twenty-three studies (7387 patients) met the inclusion criteria. Variables associated with imminent asystole (<60 min) included: deteriorating oxygenation; absence of corneal reflexes; absence of a cough reflex; blood pressure; use of vasopressors; and use of comfort medications. We identified a total of 20 unique predictive models using a wide range of variables and techniques. Many of these models also underwent secondary validation in further studies or were adapted to develop new models. This review identifies variables associated with time to asystole following withdrawal of life-sustaining treatment and summarises existing predictive models. Although several predictive models have been developed, their generalisability and performance varied. Further research and validation are needed to improve the accuracy and widespread adoption of predictive models for patients managed in intensive care units who may be eligible to donate organs following their diagnosis of death by circulatory criteria.

Socio-economic disadvantage and utilisation of labour epidural analgesia in Scotland: a population-based study†

Socio-economic deprivation is associated with adverse maternal and childhood outcomes. Epidural analgesia, the gold standard for labour analgesia, may improve maternal well-being. We assessed the association of socio-economic status with utilisation of epidural analgesia and whether this differed when epidural analgesia was advisable for maternal safety. This was a population-based study of NHS data for all women in labour in Scotland between 1 January 2007 and 23 October 2020, excluding elective caesarean sections. Socio-economic status deciles were defined using the Scottish Index of Multiple Deprivation. Medical conditions for which epidural analgesia is advisable for maternal safety (medical indications) and contraindications were defined according to national guidelines. Of 593,230 patients in labour, 131,521 (22.2%) received epidural analgesia. Those from the most deprived areas were 16% less likely to receive epidural analgesia than the most affluent (relative risk 0.84 [95%CI 0.82-0.85]), with the inter-decile mean change in receiving epidural analgesia estimated at -2% ([95%CI -2.2% to -1.7%]). Among the 21,219 deliveries with a documented medical indication for epidural analgesia, the socio-economic gradient persisted (relative risk 0.79 [95%CI 0.75-0.84], inter-decile mean change in receiving epidural analgesia -2.5% [95%CI -3.1% to -2.0%]). Women in the most deprived areas with a medical indication for epidural analgesia were still less likely (absolute risk 0.23 [95%CI 0.22-0.24]) to receive epidural analgesia than women from the most advantaged decile without a medical indication (absolute risk 0.25 [95%CI 0.24-0.25]). Socio-economic deprivation is associated with lower utilisation of epidural analgesia, even when epidural analgesia is advisable for maternal safety. Ensuring equitable access to an intervention that alleviates pain and potentially reduces adverse outcomes is crucial.

Association between inflammation and post-intensive care syndrome: a systematic review

Post-intensive care syndrome describes the physical, cognitive and emotional symptoms which persist following critical illness. At present there is limited understanding of the pathological mechanisms contributing to the development of post-intensive care syndrome. The aim of this systematic review was to synthesise current evidence exploring the association between inflammation and features of post-intensive care syndrome in survivors of critical illness. Relevant databases were systematically searched for studies of human participants exposed to critical illness. We sought studies that reported results for biomarkers with an identified role in the pathophysiology of inflammation obtained at any time-point in the patient journey and an outcome measure of any feature of post-intensive care syndrome at any point following hospital discharge. We included 32 studies, with 23 in the primary analysis and nine in a brain injury subgroup analysis. In the primary analysis, 47 different biomarkers were sampled and 44 different outcome measures were employed. Of the biomarkers which were sampled in five or more studies, interleukin-8, C-reactive protein and interleukin-10 most frequently showed associations with post-intensive care syndrome outcomes in 71%, 62% and 60% of studies, respectively. There was variability in terms of which biomarkers were sampled, time-points of sampling and outcome measures reported. Overall, there was mixed evidence of a potential association between an inflammatory process and long-term patient outcomes following critical illness. Further high-quality research is required to develop a longitudinal inflammatory profile of survivors of critical illness over the recovery period and evaluate the association with outcomes.

Frequency, kinetics and determinants of viable SARS-CoV-2 in bioaerosols from ambulatory COVID-19 patients infected with the Beta, Delta or Omicron variants

Airborne transmission of SARS-CoV-2 aerosol remains contentious. Importantly, whether cough or breath-generated bioaerosols can harbor viable and replicating virus remains largely unclarified. We performed size-fractionated aerosol sampling (Andersen cascade impactor) and evaluated viral culturability in human cell lines (infectiousness), viral genetics, and host immunity in ambulatory participants with COVID-19. Sixty-one percent (27/44) and 50% (22/44) of participants emitted variant-specific culture-positive aerosols <10μm and <5μm, respectively, for up to 9 days after symptom onset. Aerosol culturability is significantly associated with lower neutralizing antibody titers, and suppression of transcriptomic pathways related to innate immunity and the humoral response. A nasopharyngeal Ct <17 rules-in ~40% of aerosol culture-positives and identifies those who are probably highly infectious. A parsimonious three transcript blood-based biosignature is highly predictive of infectious aerosol generation (PPV > 95%). There is considerable heterogeneity in potential infectiousness i.e., only 29% of participants were probably highly infectious (produced culture-positive aerosols <5μm at ~6 days after symptom onset). These data, which comprehensively confirm variant-specific culturable SARS-CoV-2 in aerosol, inform the targeting of transmission-related interventions and public health containment strategies emphasizing improved ventilation.

SPLUNC1 as a biomarker of pulmonary exacerbations in children with cystic fibrosis

BACKGROUND

Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) is an innate defence protein that acts as an anti-microbial agent and regulates airway surface liquid volume through inhibition of the epithelial sodium channel (ENaC). SPLUNC1 levels were found to be reduced in airway secretions of adults with cystic fibrosis (CF). The potential of SPLUNC1 as a biomarker in children with CF is unknown.

METHODS

We quantified SPLUNC1, interleukin-8 (IL-8) and neutrophil elastase (NE) in sputum of CF children treated with either intravenous antibiotics or oral antibiotics for a pulmonary exacerbation (PEx)s, and in participants of a prospective cohort of CF children with preserved lung function on spirometry, followed over a period of two years.

RESULTS

Sputum SPLUNC1 levels were significantly lower before compared to after intravenous and oral antibiotic therapy for PEx. In the longitudinal cohort, SPLUNC1 levels were found to be decreased at PEx visits compared to both previous and subsequent stable visits. Higher SPLUNC1 levels at stable visits were associated with longer PEx-free time (hazard ratio 0.85, p = 0.04). SPLUNC1 at PEx visits did not correlate with IL-8 or NE levels in sputum or forced expiratory volume in one second (FEV1) but did correlate with the lung clearance index (LCI) (r=-0.53, p < 0.001).

CONCLUSION

SPLUNC1 demonstrates promising clinometric properties as a biomarker of PEx in children with CF.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

TROG 15.03/ANZUP International Multicenter Phase II Trial of Focal Ablative STereotactic RAdiotherapy for Cancers of the Kidney (FASTRACK II)

PURPOSE/OBJECTIVE(S)

Stereotactic body radiotherapy (SBRT) is an emerging non-invasive alternative for primary renal cell cancer (RCC) in patients unsuitable for surgery. The objective of the FASTRACK II clinical trial was to investigate the efficacy of SBRT for primary RCC.

MATERIALS/METHODS

This non-randomized, intergroup multi-institutional phase II study was activated in 7 Australian centers and 1 Dutch center, through the Trans Tasman Radiation Oncology Group (TROG) and the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP). Eligible patients had biopsy confirmed diagnosis of primary RCC with a single lesion within a kidney, ECOG performance ≤2 and were medically inoperable, high risk or declined surgery. For tumors ≤4 cm a single fraction of 26 Gy was prescribed, for tumors > 4 cm, 42 Gy in three fractions was prescribed. The primary outcome of the study was to estimate the efficacy of SBRT for primary RCC, defined as local control based on RECIST criteria. The study was powered assuming that 1-year local control would be 90%, with the null hypothesis of ≤80% considered undesirable and not worthy of proceeding to a future randomized controlled trial.

RESULTS

Between July 2016 and February 2020, 70 patients were enrolled with a median follow-up of 42 months. Median age was 77 years. Forty-nine patients were male (70%), median BMI was 32 and median Charlson comorbidity score was 7. The median [IQR] RENAL complexity score was 8 [7-10]. Biopsy confirmation was 100%. Twenty-three patients (33%) had T1a disease. The median (interquartile range [IQR]) tumor size was 4.6cm [3.7-5.5]; it was 3.3cm [3.0-3.6] in those receiving single fraction (n = 23), and 5.3cm [4.6-6.0] in those receiving 3-fraction SBRT (n = 47). During real-time pre-treatment quality assurance review, 10 cases (14.3%) required resubmission for protocol deviation, 2119 variables were assessed at final review, and final protocol compliance was 99.3%. Seven (10%) patients experienced grade 3 treatment-related adverse events, with no grade 4 or 5 events observed. Eleven (16%) patients reported no adverse events. Local control was 100% throughout the lifetime of the trial (p<0.001). Cancer-specific survival was also 100% throughout the lifetime of the trial. Freedom from distant failure (95% CIs) at 1 and 3 years was 99% (90-100%). Overall survival (95% CIs) at 1 and 3 years was 99% (90-100%) and 82% (70-89%), respectively. Baseline mean eGFR (95% CI) was 61.1 mLs/min (56.6; 65.6) and reduced by -10.8 mLs/min (-13.0; -8.6) by 1-year, by -14.6 mLs/min (-17.0; -12.2) by 2-years and plateaued thereafter.

CONCLUSION

In the first multicenter prospective trial of a non-surgical primary RCC cohort, enrolling mostly T1b+ disease, SBRT was an effective treatment strategy with no observed local failures. We observed an acceptable side effect profile and renal function after SBRT. These outcomes support the design of a future randomized clinical trial of SBRT versus surgery for primary RCC. The trial was registered with ID: NCT02613819.

Striatal and thalamic automatic segmentation, morphology, and clinical correlates in Parkinsonism: Parkinson's disease, multiple system atrophy and progressive supranuclear palsy

Parkinson's disease (PD), multisystem atrophy (MSA), and progressive supranuclear palsy (PSP) present similarly with bradykinesia, tremor, rigidity, and cognitive impairments. Neuroimaging studies have found differential changes in the nigrostriatal pathway in these disorders, however whether the volume and shape of specific regions within this pathway can distinguish between atypical Parkinsonian disorders remains to be determined. This paper investigates striatal and thalamic volume and morphology as distinguishing biomarkers, and their relationship to neuropsychiatric symptoms. Automatic segmentation to calculate volume and shape analysis of the caudate nucleus, putamen, and thalamus were performed in 18 PD patients, 12 MSA, 15 PSP, and 20 healthy controls, then correlated with clinical measures. PSP bilateral thalami and right putamen were significantly smaller than controls, but not MSA or PD. The left caudate and putamen significantly correlated with the Neuropsychiatric Inventory total score. Bilateral thalamus, caudate, and left putamen had significantly different morphology between groups, driven by differences between PSP and healthy controls. This study demonstrated that PSP patient striatal and thalamic volume and shape are significantly different when compared with controls. Parkinsonian disorders could not be differentiated on volumetry or morphology, however there are trends for volumetric and morphological changes associated with PD, MSA, and PSP.

SABRSeq: A Randomized Phase Ib Trial of SABR Sequencing with Pembrolizumab in Metastatic Non-Small Cell Lung Cancer (NSCLC)

PURPOSE/OBJECTIVE(S)

The optimal sequencing of stereotactic ablative body radiotherapy (SABR) with anti-PD1 checkpoint blockade is unknown. The purpose of SABRseq was to assess the toxicity of the combination of SABR delivered either before or after the commencement of pembrolizumab. The central hypothesis is that the treatment combination will have a safety profile that is clinically acceptable and demonstrate anti-tumor efficacy. Furthermore, we hypothesize that differences in systemic immune activation will be observed between treatment arms.

MATERIALS/METHODS

This was a single institutional phase Ib randomized clinical trial (Trial ID NCT03307759). Eligible patients had metastatic NSCLC, ECOG performance 0-1, and had not received prior checkpoint immunotherapy, high-dose radiation (>36 Gy) within 6 months, or either systemic or radiation therapy within 4 weeks of randomization. Eligible patients had either TPS≥50% PD-L1 expression in the first-line or TPS≥1% PD-L1 expression with prior chemotherapy exposure. Patients were randomized to SABR before the commencement of pembrolizumab [ARM1] or SABR commencing after pembrolizumab [ARM2]. SABR was delivered in a single fraction of 18-20 Gy to 1-3 lesions. The primary endpoint was treatment-related adverse events (AE's) related to SABR and/or pembrolizumab. Secondary endpoints included best overall response (BOR), overall survival (OS), and progression-free survival (PFS). Translational objectives included the evaluation of longitudinal changes in immunological cellular subsets within peripheral blood to explore changes in systemic immunity and circulating tumor DNA (ctDNA) dynamics.

RESULTS

Between December 2017 and December 2019, 13 patients were randomized. The median follow-up was 37 months. The study was closed early due to poor accrual. Median age was 66 years, with 11 patients (84%) having adenocarcinoma. Nine (69%) were enrolled in the first-line setting. The median [range] number of lesions was 6 [3-11]. The median [range] cycles of pembrolizumab delivered in ARM 1 was 13 [12-32] and ARM 2 was 9 [3-34]. Grade 3 treatment-related AEs were experienced in 0 of 5 patients in ARM1 and in 1 of 8 patients in ARM 2 (hyperglycemia). There were no grade 4 or 5 adverse events reported. The BOR by both RECIST and iRECIST criteria was CR in one patient, PR in seven patients, SD in five patients. Median (95% Cis) PFS was 12.4 months (6.3-21.0), and median (95% Cis) OS was 47.1 months (12.6-not reached; 2-year point estimate 62% [31-82]). Mass cytometry was used on serial peripheral blood samples to examine changes in the frequency of immune cells, changes in T cell activation, differentiation and functional polarization state. Targeted sequencing was performed to assess ctDNA. Translational outcomes will be presented.

CONCLUSION

There was no evidence of a concerning safety signal from either SABR before or after start of pembrolizumab. The combination demonstrated activity with promising PFS and OS and is worthy of evaluation in larger randomized trials.

Learner and supervisor perspectives on factors that influence the effectiveness of educational supervision in postgraduate pharmacy education

Introduction

Educational supervision underpins the Centre for Pharmacy Postgraduate Education’s (CPPE) publicly funded national training pathways for pharmacy professionals working in primary care in England, mirroring arrangements for postgraduate medical specialty training. The educational supervision provided by CPPE comprises both one-to-one support and group learning to enable pharmacy professionals transitioning into primary care roles to progress with their education, manage workplace challenges and practise safely.1 However, little is known about its effectiveness.

Aim

The aim of this study was to explore learner and supervisor perceptions of factors that influence the effectiveness of educational supervision.

Methods

The study used a concurrent embedded mixed methods design. Following institutional ethical approval, data were collected using a validated online survey comprising items adapted from the Manchester Clinical Supervision Scale (MSCC-26®)2 and the Academy of Medical Educators’ (AOME) framework. The survey, comprising a 25-item questionnaire, together with open-ended questions inviting respondents to explain their ratings, was sent to all 902 learners enrolled on a CPPE primary care training pathway and 52 CPPE education supervisors in July 2020. Statistical data were analysed with SPSS®, using non-parametric tests due to negative data skewing. Responses to open-ended questions were analysed with NVivo® using framework analysis and then compared with the statistical data.

Results

187 learners (20.7%) and 51 supervisors (98%) responded to the survey. Overall, 82.5% learners and 100% of supervisors rated the educational supervision provided by CPPE as effective. Framework analysis of responses to open-ended survey questions identified three main factors perceived by learners and supervisors to influence the effectiveness of educational supervision: supervisor-learner relationships; a safe learning environment; and peer support. Within the theme of supervisor-learner relationships, trust and rapport was awarded the highest mean score of any survey item. Trust and rapport and the ability of supervisors to establish a safe learning environment showed significant positive correlations (ρ(8) = .48, p &lt; .001 and ρ(8) = .74, p &lt; .001 respectively) with overall scores for the effectiveness of educational supervision. Peer support did not form part of the survey yet was mentioned spontaneously in many learner and supervisor responses. Learners described the benefits of educational supervision in providing opportunities to learn from peers, to receive peer feedback and to obtain peer and supervisor support for personal issues such as workplace challenges.

Discussion/Conclusion

Consistent with the literature on factors that influence the effectiveness of clinical supervision in other healthcare professions3, the results indicate that educational supervision provided by CPPE was more effective when levels of trust and rapport between learners and supervisors were high and when supervisors were able to create a safe learning environment. However, peer support has not previously been identified as an influencing factor. This is an important finding, reflecting that unlike other disciplines, the educational supervision provided by CPPE encompasses both one-to-one and group learning sessions. Limitations of the study include the relatively low learner response rate, the effect of the COVID-19 pandemic which required provision of online supervision and the potential bias from insider research.

References

1. Styles, M., Middleton, H., Schafheutle, E., et al. Educational supervision to support pharmacy professionals’ learning and practice of advanced roles. Int J Clin Pharm. 2022;44:781-786.

2. Winstanley, J., White, E. The MCSS-26©: revision of the Manchester clinical supervision scale© using the Rasch measurement model. J Nurs Meas 2011;19:(3):60-178.

3. Kilminster, S., Cottrell, D., Grant, J., et al. AMEE Guide No. 27: Effective educational and clinical supervision. Med Teach. 2007;29:(1):2-19.

JS04.6.A The landscape of tumor cell states and spatial organization in H3-K27M mutant diffuse midline glioma across age and location

Background

Histone 3 lysine27-to-methionine mutations (H3-K27M) frequently occur in childhood diffuse midline gliomas (DMGs) of the pons, thalamus and spinal cord, presumed to be driven by the specific spatiotemporal context of these midline locations during postnatal development. While most common in the pons and at mid-childhood ages, the same oncohistone mutation is recurrently detected in adult DMGs and throughout different midline regions. The potential heterogeneity of tumors at different ages and in different anatomical locations of the midline are vastly understudied.

Material and Methods

Through dissecting the transcriptomic, epigenomic and spatial architectures of a comprehensive cohort of patient H3-K27M DMGs - spanning the age range from 2-68 years and locations from spinal cord to thalamus - at single cell resolution, we delineate how age- and location-dependent contexts shape glioma cell-intrinsic and -extrinsic features in light of the shared driver mutation.

Results

We identify that oligodendrocyte precursor (OPC)-like cells constitute the stem-like compartment in H3-K27M DMGs across all clinico-anatomical groups, however, depending on location, display varying levels of maturity resembling less differentiated pre-OPCs or more mature OPCs further differentiated along the oligodendroglial lineage. We further demonstrate increased mesenchymal cell states in adult tumors, which we link to age-related differences in glioma-associated immune cell compartments. We for the first time resolve the spatial organization of H3-K27M DMG cell types in intact patient tissues, identifying a local niche of the oligodendroglial lineage.

Conclusion

Our study provides a powerful resource for rational modeling and therapeutic frameworks taking into account determinants of age and location in this lethal glioma group.

Abstract 107: Adoptive Transfer Reveals That T Cell-Derived Reactive Oxygen Species Contributes To Pregnancy-Induced Renal Damage In The Dahl SS Rat

Previous work from our lab demonstrated that Dahl SS rats develop a pregnancy-specific increase in blood pressure and proteinuria, also known as maternal syndrome (MS). Both T cells and reactive oxygen species (ROS) have been implicated in MS, and genetic deletion of either resulted in protection from MS in the Dahl SS rat. Therefore, we tested the hypothesis that ROS produced from T cells contributes to the development of MS in the Dahl SS. An adoptive transfer of splenocytes was utilized to reconstitute T cells from wild type Dahl SS (SS→CD247) or SS p67phox-/- (p67phox→CD247), which lack the ability to generate NOX2-derived ROS, into SS CD247-/- rats by intraperitoneal injection at postnatal day 5 to investigate the oxidative capacity of T cells. Injected SS CD247-/- rats were mated at 9-11 weeks of age with naïve littermate males, and virgin controls were run in parallel. Baseline protein excretion rates were comparable between mated groups (72±12 vs 66±9 mg/day, p> 0.05, n=10/group, SS→CD247 vs p67phox→CD247, respectively), yet the SS→CD247 develop an increase in proteinuria throughout pregnancy that is significantly elevated relative to p67phox→CD247 rats (217±65 vs 114±14 mg/day, p< 0.05). There was a trending decrease in creatinine clearance in the SS→CD247 vs p67phox→CD247 at the end of the study (0.37±0.03 vs 0.46±0.06, p =0.1), but MAP did not differ between groups. There was however, an increase in uterine artery resistance index as assessed by Doppler ultrasound at GD20 in the SS→CD247 relative p67phox→CD247 (0.72±0.03 vs 0.61±0.02, p <0.01) indicating an impairment in blood flow leading to the placenta. While, there was no difference observed in the number of infiltrating leukocytes into the kidneys between SS→CD247 vs p67phox→CD247, a significant correlation was observed between the number of infiltrating CD4+ T cells and the late pregnancy proteinuria levels (R 2 =0.7973) in the SS→CD247 mated group while no correlation was observed in the p67phox→CD247 (R 2 =0.0472). Taken together, adoptive transfer of T cells lacking NOX2 into SS CD247-/- rats fails to induce pregnancy associated renal damage and uterine artery blood flow impairment indicating a potential role for ROS in MS.

Abstract P075: Functional NOX2 In T Cells Amplifies Salt-Sensitive Hypertension And Associated Renal Damage

Infiltrating T cells in the kidney amplify salt-sensitive (SS) hypertension and renal damage, but the mechanisms are not known. Genetic deletion of T cells (SS CD247-/- ) or the p67phox subunit of NOX2 (SS p67phox-/- ) attenuates salt-sensitive hypertension in the Dahl SS rat. We hypothesized that reactive oxygen species (ROS) produced by NOX2 in T cells drive the SS phenotype and renal damage. T cells were reconstituted by adoptively transferring ~10 million splenocytes from the Dahl SS (SS→CD247, n=14), the SS p67phox-/- (p67phox→CD247, n=19), or PBS only (PBS→CD247, n=8), into the peritoneum of SS CD247-/- rats on postnatal day 5. Animals were instrumented with radiotelemeters at 8 weeks of age. After a week of recovery, blood pressure and albumin excretion were measured while rats were fed a low salt (LS, 0.4% NaCl) diet. Rats were then switched to a high salt (HS, 4.0% NaCl) diet for 21 days, with continuous blood pressure measurements and urine collections every 7 days. On day 22, the rats were euthanized, and their kidneys were perfused and collected for histology and renal immune cell characterization by flow cytometry. At baseline there was no detectable difference in mean arterial pressure (MAP) between groups (124±2 vs 123±2 vs 116±2 mmHg; SS→CD247 vs p67phox→CD247 vs PBS→CD247, respectively). After 21 days of HS, MAP was significantly greater in the SS→CD247 compared to the p67phox→CD247 rats (155±3 vs 144±2 mmHg; p<0.001) and the PBS→CD247 rats (155±3 vs 141±3 mmHg; p<0.001). Indices of renal damage identified no difference in albuminuria between SS→CD247 and p67phox→CD247 on LS (25.8±4.7 vs 23.2±3.2 mg/day). After 21 days of HS, albuminuria was significantly greater in the SS→CD247 (242.8±30.3 mg/day) compared to the p67phox→CD247 (175.5 ± 14.3 mg/day, p<0.03) and PBS→CD247 (135.9±27.8 mg/day, p<0.005). There was no difference between p67phox→CD247 and PBS→CD247 in albuminuria or MAP during LS or HS. The lack of CD3+ cells in the PBS→CD247 but presence of CD3+ cells in rats receiving the T cell transfer demonstrated the effectiveness of the adoptive transfer. These results indicate that ROS production by T cells participates in the amplification of salt-sensitive hypertension and renal damage.

Abstract 028: Toll-Like Receptor 4 Promotes Renal Immune Cell Infiltration And The Development Of Renal Damage During Dahl Salt-Sensitive Hypertension

Previous work in our laboratory has implicated a significant role for the immune system in potentiating the hypertensive and kidney damage phenotypes which occur in the Dahl Salt-Sensitive (SS) rat. Toll-like receptors (TLRs), usually expressed on macrophages, play a key role in the innate immune system. A number of TLRs have been implicated in cardiovascular disease and chronic kidney disease with particular interest in TLR4, which specifically binds gram-negative lipopolysaccharide or endogenous molecules produced as a result of tissue injury. We previously performed a transcriptomic analysis which demonstrated TLR4 upregulation in renal medullary tissue of Dahl SS rats fed a high salt (4.0% NaCl) diet. The present study tests the hypothesis that TLR4 influences high salt diet-induced hypertension and renal damage in the Dahl SS rat. Using CRISPR/Cas9 technology, a mutation was generated in the TLR4 gene on the Dahl SS background, creating a 1-bp frameshift deletion resulting in a premature stop codon. SS TLR4-/- males and parental Dahl SS males (SS TLR4+/+ ), maintained on a 0.4% NaCl chow, underwent carotid artery telemetry implantation at 7 weeks of age. After recovery and baseline mean arterial pressure (MAP) recordings (day 0: 125.6 ± 0.5 vs 124.2 ± 2 mmHg), animals were switched to a 4.0% NaCl chow for 3 weeks. Overnight urine collections occurred once during the low salt period and weekly throughout the high salt challenge. Kidneys were flushed prior to euthanasia. Although SS TLR4-/- MAP was not different from SS TLR4+/+ during the high salt challenge (day 21: 176.8 ± 14 mmHg, n=2 vs 172.3 ± 18 mmHg, n=4), high salt day 21 urinary albumin excretion was significantly reduced in SS TLR4-/- (272.7 ± 65 mg/day, n=5, p<0.01) compared to SS TLR4+/+ (427.5 ± 67 mg/day, n=7), indicating reduced renal damage in TLR4 absence. Furthermore, flow cytometric analysis of isolated renal immune cells indicated a 33% reduction in CD45+ total leukocytes (5.0 ± 1.2 vs 3.4 ± 0.9 x10 6 cells) and a 31% reduction in CD11bc+ monocytes/macrophages (3.9 ± 0.9 vs 2.6 ± 0.7 x10 6 cells) in SS TLR4-/- (n=5) vs SS TLR4+/+ (n=7) kidneys. Together, these data indicate that TLR4 may drive the immune response during the induction and progression of salt-sensitive hypertension and renal disease.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Comparison of ultra-low, low and high concentration local anaesthetic for labour epidural analgesia: a systematic review and network meta-analysis

Lumbar epidural is the gold standard for labour analgesia. Low concentrations of local anaesthetic are recommended. This network meta‐analysis investigated whether further reducing the concentration of local anaesthetic can improve maternal and neonatal outcomes without compromising analgesia. We conducted a systematic search of relevant databases for randomised controlled trials comparing high (>0.1%), low (>0.08% to ≤0.1%) or ultra‐low (≤0.08%) concentration local anaesthetic (bupivacaine or equivalent) for labour epidural. Outcomes included mode of delivery, duration of labour and maternal/neonatal outcomes. Bayesian network meta‐analysis with random‐effects modelling was used to calculate odds ratios or weighted mean differences and 95% credible intervals. A total of 32 studies met inclusion criteria (3665 women). The total dose of local anaesthetic received increased as the concentration increased; ultra‐low compared with low (weighted mean difference −14.96 mg, 95% credible interval [−28.38 to −1.00]) and low compared with high groups (weighted mean difference −14.99 [−28.79 to −2.04]), though there was no difference in the number of rescue top‐ups administered between the groups. Compared with high concentration, ultra‐low concentration local anaesthetic was associated with increased likelihood of spontaneous vaginal delivery (OR 1.46 [1.18 to 1.86]), reduced motor block (Bromage score >0; OR 0.32 [0.18 to 0.54]) and reduced duration of second stage of labour (weighted mean difference −13.02 min [−21.54 to −4.77]). Compared with low, ultra‐low concentration local anaesthetic had similar estimates for duration of second stage of labour (weighted mean difference −1.92 min [−14.35 to 10.20]); spontaneous vaginal delivery (OR 1.07 [0.75 to 1.56]; assisted vaginal delivery (OR 1.35 [0.75 to 2.26]); caesarean section (OR 0.76 [0.49 to 1.22]); pain (scale 1–100, weighted mean difference −5.44 [−16.75 to 5.93]); and maternal satisfaction. Although a lower risk of an Apgar score < 7 at 1 min (OR 0.43 [0.15 to 0.79]) was reported for ultra‐low compared with low concentration, this was not sustained at 5 min (OR 0.12 [0.00 to 2.10]). Ultra‐low concentration local anaesthetic for labour epidural achieves similar or better maternal and neonatal outcomes as low and high concentration, but with reduced local anaesthetic consumption.

Hospital re-admission after critical care survival: a systematic review and meta-analysis

Survivors of critical illness frequently require increased healthcare resources after hospital discharge. We undertook a systematic review and meta-analysis to assess hospital re-admission rates following critical care admission and to explore potential re-admission risk factors. We searched the MEDLINE, Embase and CINAHL databases on 05 March 2020. Our search strategy incorporated controlled vocabulary and text words for hospital re-admission and critical illness, limited to the English language. Two reviewers independently applied eligibility criteria and assessed quality using the Newcastle Ottawa Score checklist and extracted data. The primary outcome was acute hospital re-admission in the year after critical care discharge. Of the 8851 studies screened, 87 met inclusion criteria and 41 were used within the meta-analysis. The analysis incorporated data from 3,897,597 patients and 741,664 re-admission episodes. Pooled estimates for hospital re-admission after critical illness were 16.9% (95%CI: 13.3-21.2%) at 30 days; 31.0% (95%CI: 24.3-38.6%) at 90 days; 29.6% (95%CI: 24.5-35.2%) at six months; and 53.3% (95%CI: 44.4-62.0%) at 12 months. Significant heterogeneity was observed across included studies. Three risk factors were associated with excess acute care rehospitalisation one year after discharge: the presence of comorbidities; events during initial hospitalisation (e.g. the presence of delirium and duration of mechanical ventilation); and subsequent infection after hospital discharge. Hospital re-admission is common in survivors of critical illness. Careful attention to the management of pre-existing comorbidities during transitions of care may help reduce healthcare utilisation after critical care discharge. Future research should determine if targeted interventions for at-risk critical care survivors can reduce the risk of subsequent rehospitalisation.

Airway events in obese vs. non-obese elective surgical patients: a cross-sectional observational study

Obesity is an increasingly prevalent comorbidity within the UK population. The aim of this study was to determine the proportion of obese patients in an elective surgical population. The second aim was to determine the choice of airway equipment and incidence of airway events in obese vs. non-obese patients. We conducted a cross-sectional observational study over two 24-h periods in March 2018 across 39 hospitals in the greater London area. Data were collected regarding 1874 patients. The incidence of obesity was 32% in the study population compared with 26% in the general UK population (p < 0.0001). Minor airway events were defined as: desaturation to S_p O₂ < 90%; failed mask ventilation; supraglottic airway device problem; aspiration; airway trauma and difficult intubation; or recognised oesophageal intubation. Major airway events were defined as: unrecognised oesophageal intubation; a 'cannot intubate cannot oxygenate' emergency; the need for unplanned front-of-neck airway; cardiac arrest; or unplanned intensive care unit admission due to an airway event. In total, 89 minor and two major airway events were recorded. Obese patients were more likely to experience a minor airway event (RR 2.39, 95%CI 1.60-3.57), the most common being desaturation (S_p O₂ < 90%). The use of a supraglottic airway device in obese vs. non-obese patients was associated with increased airway events (RR 3.46 [1.88-6.40]). Tracheal intubation vs. supraglottic airway device use increased with obesity class but was not associated with a decrease in airway events (RR 0.90 [0.53-1.55]). Our data suggest that obesity is more common in the elective surgical vs. general population and minor airway events are more common in obese vs. non-obese elective patients.

Dysphagia presentation and management following COVID-19: an acute care tertiary centre experience

OBJECTIVES

As the pathophysiology of COVID-19 emerges, this paper describes dysphagia as a sequela of the disease, including its diagnosis and management, hypothesised causes, symptomatology in relation to viral progression, and concurrent variables such as intubation, tracheostomy and delirium, at a tertiary UK hospital.

RESULTS

During the first wave of the COVID-19 pandemic, 208 out of 736 patients (28.9 per cent) admitted to our institution with SARS-CoV-2 were referred for swallow assessment. Of the 208 patients, 102 were admitted to the intensive treatment unit for mechanical ventilation support, of which 82 were tracheostomised. The majority of patients regained near normal swallow function prior to discharge, regardless of intubation duration or tracheostomy status.

CONCLUSION

Dysphagia is prevalent in patients admitted either to the intensive treatment unit or the ward with COVID-19 related respiratory issues. This paper describes the crucial role of intensive swallow rehabilitation to manage dysphagia associated with this disease, including therapeutic respiratory weaning for those with a tracheostomy.

Anaemia in cardiac surgery - a retrospective review of a centre's experience with a pre-operative intravenous iron clinic

Pre-operative anaemia is associated with higher rates of transfusion and worse outcomes, including prolonged hospital stay, morbidity and mortality. Iron deficiency is associated with significantly lower haemoglobin levels throughout the peri-operative period and more frequent blood transfusion. Correction of iron stores before surgery forms part of the first pillar of patient blood management. We established a pre-operative anaemia clinic to aid identification and treatment of patients with iron deficiency anaemia scheduled for elective cardiac surgery. We present a retrospective observational review of our experience from January 2017 to December 2019. One-hundred and ninety patients received treatment with intravenous iron, a median of 21 days before cardiac surgery. Of these, 179 had a formal laboratory haemoglobin level measured before surgery, demonstrating a median rise in haemoglobin of 8.0 g.l^-1 . Patients treated with i.v. iron demonstrated a significantly higher incidence of transfusion (60%) compared with the non-anaemic cohort (22%) during the same time period, p < 0.001. Significantly higher rates of new requirement for renal replacement therapy (6.7% vs. 0.6%, p < 0.001) and of stroke (3.7% vs. 1.2%, p = 0.010) were also seen in this group compared with those without anaemia, although there was no significant difference in in-hospital mortality (1.6% vs. 0.8%, p = 0.230). In patients where the presenting haemoglobin was less than 130 g.l^-1 , but there was no intervention or treatment, there was no difference in rates of transfusion or of complications compared with the anaemic group treated with iron. In patients with proven iron deficiency anaemia, supplementation with intravenous iron showed only a modest effect on haemoglobin and this group still had a significantly higher transfusion requirement than the non-anaemic cohort. Supplementation with intravenous iron did not improve outcomes compared with patients with anaemia who did not receive intravenous iron and did not reduce peri-operative risk to non-anaemic levels. Questions remain regarding identification of patients who will receive most benefit, the use of concomitant treatment with other agents, and the optimum time frames for treatment in order to produce benefit in the real-world setting.

Long-term Survival with 18-Fluorodeoxyglucose Positron Emission Tomography-directed Therapy in Non-small Cell Lung Cancer with Synchronous Solitary Brain Metastasis

AIMS

At diagnosis, <1% of patients with non-small cell lung cancer (NSCLC) have synchronous solitary brain metastasis (SSBM). In prior cohorts without 18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) staging, definitive treatment to intracranial and intrathoracic disease showed a 5-year overall survival (OS) of 11-21%. We investigated the long-term survival outcomes for patients with SSBM NSCLC, diagnosed in the FDG-PET/CT era and treated definitively with local therapies to both intracranial and intrathoracic sites of disease.

MATERIALS AND METHODS

This retrospective study assessed patients staged with FDG-PET/CT who received definitive lung and SSBM treatment from February 1999 to December 2017. A lung-molecular graded prognostic assessment (lung-molGPA) score was assigned for each patient using age, performance status score, and, where carried out, molecular status. Overall survival and progression-free survival (PFS) were calculated using Kaplan-Meier methods. Cox proportional hazard models determined OS and PFS prognostic factors.

RESULTS

Forty-nine patients newly diagnosed with NSCLC and SSBM had a median age of 63 years (range 34-76). The median follow-up of all patients was 3.9 years. Thirty-three patients (67%) had ≥T2 disease, 23 (47%) had ≥N2. At 2 years, 45% of first failures were intracranial only (95% confidence interval 30-59). At 3 and 5 years, OS was 45% (95% confidence interval 32-63) and 30% (95% confidence interval 18-51), respectively. In ≥N1 disease, 5-year OS was 34% (95% confidence interval 18-63). The 3- and 5-year PFS was 8% (95% confidence interval 3-22) and 0%, respectively. Higher lung-molGPA was associated with longer OS (hazard ratio 0.26, 95% confidence interval 0.11-0.61, P = 0.002). Higher lung-molGPA (hazard ratio 0.33, 95% confidence interval 0.15-0.71, P = 0.005) and lower N-stage (hazard ratio 1.56, 95% confidence interval 1.13-2.15, P = 0.007) were associated with longer PFS.

CONCLUSIONS

Definitive treatment of patients with NSCLC and SSBM staged with FDG-PET/CT can result in 5-year survivors, including those with ≥N1 disease.

Predictors of major bleeding following an acute coronary event: insights from a national study of 5,116 consecutive patients in clinical practice

Background

Major bleeding after acute coronary syndrome (ACS) predicts a poor outcome. Although predictors of major bleeding following ACS have been validated, these have been mostly in clinical trial populations and few contemporary analyses have been undertaken in clinical practise

Methods

Major bleeding was assessed in a national study of ACS and antiplatelet choice. A total of 5116 consecutive patients [Clopidogrel (n 2,491, 2011–13) and Ticagrelor (n 2,625, 2013–16)] were enrolled in 5 UK hospitals. Clinical outcomes were identified from a national coding database (n=59.5 million) with bleeding events tracked to 11 health care facilities. Bleed severity was independently adjudicated by 2 consultant cardiologists, blinded to antiplatelet, sequence and year. Bleeding events were categorised using BARC 3–5 and PLATO criteria. A logistic regression analysis was used to define independent predictors of bleeding.

Results

The median age was 68 (IQR57–78, 30.5%&gt;75), 34% were female. 39% underwent PCI and 13% coronary artery bypass surgery. Clinical outcome data was 100% complete. 1-year mortality was 12.9%. Of 1193 icd10 codes for bleeding or anaemia 165 (3.2%) and 193 (3.8%) patients were adjudicated to have suffered a BARC 3–5 and PLATO major bleeding respectively. Independent predictors common between PLATO major and BARC 3–5 bleeding, in the year following ACS, were CRUSADE score &gt;40 (OR 1.63, CI 1.1–2.4, p=0.008) moderate left ventricular systolic dysfunction (OR, 1.65, CI: 1.2–2.4, p=0.006), age (OR per year increase in age 1.03, CI 1.02–1.05, p&lt;0.001) and subsequent coronary artery bypass surgery (OR 2.6, CI 1.8–3.8, p&lt;0.001)

Conclusion

In a broad real-world population of ACS, CRUSADE score &gt;40, incorporating simple clinical and laboratory criteria, remained an independent predictor of major bleeding using 2 internationally recognised bleed criteria

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): Liverpool university hospitals; North-West Educational Cardiac Group

Neutrophil Gelatinase-associated Lipocalin as a Marker of Postoperative Acute Kidney Injury Following Cardiac Surgery in Patients with Preoperative Kidney Impairment

INTRODUCTION

Acute kidney injury (AKI) is a serious complication of cardiac surgery. The current 'gold standard' for determining AKI is change in serum creatinine and urine output, however, this change occurs relatively late after the actual injury occurs. Identification of new biomarkers that detect early AKI is required. Recently, new biomarkers, such as the NephroCheck® Test and AKIRisk have also been tested and found to be good indicators of AKI. Neutrophil gelatinase-associated lipocalin (NGAL) has shown promise in paediatric patients but has displayed varied results in adult populations, particularly post cardiac surgery. The aim of this study was to assess the value of urinary NGAL as a biomarker of AKI in patients with pre-existing renal impairment (eGFR >15ml/min to eGFR<60ml/min).

METHODS

A post-hoc analysis of urinary NGAL concentrations from 125 patients with pre-existing kidney impairment, who participated in a randomised trial of haemofiltration during cardiac surgery, was undertaken. Urinary NGAL was measured using ELISA at baseline, post-operatively and 24 and 48 hours after surgery, and serum creatinine was measured pre and postoperatively and then at 24, 48, 72 and 96 hours as routine patient care. NGAL concentrations were compared in patients with and without AKI determined by changes in serum creatinine concentrations. A Kaplan-Meier plot compared survival for patients with or without AKI and a Cox proportional hazards analysis was performed to identify factors with the greatest influence on survival.

RESULTS

Following surgery, 43% of patients developed AKI (based on KDIGO definition). Baseline urinary NGAL was not found to be significantly different between patients that did and did not develop AKI. Urinary NGAL concentration was increased in all patients following surgery, regardless of whether they developed AKI and was also significant between groups at 24 (p=0.003) and 48 hours (p<0.0001). Urinary NGAL concentrations at 48 hours correlated with serum creatinine concentrations at 48 hours (r=0.477, p<0.0001), 72 hours (r=0.488, p<0.0001) and 96 hours (r=0.463, p<0.0001). Urinary NGAL at 48 hours after surgery strongly predicted AKI (AUC=0.76; P=0.0001). A Kaplan- Meier plot showed that patients with postoperative AKI had a significantly lower 7-year survival compared with those without AKI. Postoperative urinary NGAL at 48 hours >156ng/mL also strongly predicted 7-year survival. However, additive EuroSCORE, age, current smoking and post-operative antibiotics usage were distinctly significantly more predictive of 7-year survival as compared with postoperative urinary NGAL at 48 hours >156ng/mL.

CONCLUSIONS

Our study demonstrated that postoperative urinary NGAL levels at 48 hours postsurgery strongly predicts the onset or severity of postoperative AKI based on KDIGO classification in patients with preoperative kidney impairment and were also strongly related to 7-year survival.

Host Preference and Olfaction in Drosophila mojavensis

Many organisms live in complex environments that vary geographically in resource availability. This environmental heterogeneity can lead to changes within species in their phenotypic traits. For example, in many herbivorous insects, variation in host plant availability has been shown to influence insect host preference behavior. This behavior can be mediated in part through the insect olfactory system and the odor-evoked responses of olfactory sensory neurons (OSNs), which are in turn mediated by their corresponding odorant receptor genes. The desert dwelling fly Drosophila mojavensis is a model species for understanding the mechanisms underlying host preference in a heterogeneous environment. Depending on geographic region, one to multiple host plant species are available. Here, we conducted electrophysiological studies and found variation in responses of ORNs to host plant volatiles both within and between 2 populations-particularly to the odorant 4-methylphenol. Flies from select localities within each population were found to lack a response to 4-methylphenol. Experiments then assessed the extent to which these electrophysiological differences were associated with differences in several odor-mediated behavioral responses. No association between the presence/absence of these odor-evoked responses and short range olfactory behavior or oviposition behavior was observed. However, differences in odor-induced feeding behavior in response to 4-methylphenol were found. Localities that exhibit an odor-evoked response to the odorant had increased feeding behavior in the presence of the odorant. This study sets the stage for future work examining the functional genetics underlying variation in odor perception.

Use of an automated knot fastener shortens operative times in minimally invasive mitral valve repair

INTRODUCTION

Longer durations of cardiopulmonary bypass and aortic cross clamp are associated with increased morbidity and mortality. Little is known about the effect of automated knot fasteners (Cor-Knot®) in minimally invasive mitral valve repair on operative times and outcomes. The aim of this study was to evaluate whether these devices shortened cardiopulmonary bypass and aortic cross clamp times and whether this impacted on postoperative outcomes.

MATERIALS AND METHODS

All patients undergoing isolated minimally invasive mitral valve repair by a single surgeon between March 2011 and March 2016 were included (n = 108). Two cohorts were created based on the use (n = 52) or non-use (n = 56) of an automated knot fastener. Data concerning intraoperative variables and postoperative outcomes were collected and compared.

RESULTS

Preoperative demographics were well matched between groups with no significant difference in logistic Euroscore (manual vs automated: median 3.1, interquartile range, IQR, 2.1-5.5, vs 5.4, IQR 2.2-8.3; P = 0.07, respectively). Comparing manually tied knots to an automated fastener, cardiopulmonary bypass and aortic cross clamp times were significantly shorter in the automated group (cardiopulmonary bypass: median 200 minutes, IQR 180-227, vs 165 minutes (IQR 145-189 minutes), P < 0.001; aortic cross clamp 134 minutes (IQR 121-150 minutes) vs 111 minutes (IQR 91-137 minutes), P < 0.001, respectively). There was no mortality and no strokes, nor were there any differences in postoperative outcomes including reoperation for bleeding, renal failure, intensive care or hospital stay.

CONCLUSIONS

The use of an automated knot fastener significantly reduces cardiopulmonary bypass and aortic cross clamp times in minimally invasive mitral valve repair but this does not translate into an improved clinical outcome.

Striving for Balance: Palliative Care Patients’ Experiences of Making Everyday Choices

A fundamental principle of palliative care is the provision of patient-centred care, an approach explicitly based on the patient's perspective. Although much attention has been given to determining patients’ preferences for involvement in medical decisions, choices related to personal and nursing care routines have been largely ignored in the literature. Data from participant observations of nurse-patient interactions involving 16 palliative care patients and their nurses as well as 10 in-depth open-ended interviews with patients were analyzed using grounded theory methods. Although the choices made by patients appeared uncomplicated on the surface, the context of unfamiliarity, uncertainty, and unpredictability in palliative care increased the underlying complexity of decision making. Through a process of deliberation and trade-offs, patients attempted to regain or maintain some balance in their lives. This process of striving for balance consisted of three overlapping phases: weighing things up, communicating choice, and living with one's choices.