Inhibition of calcium-triggered secretion by hydrocarbon-stapled peptides.

Membrane fusion triggered by Ca2+ is orchestrated by a conserved set of proteins to mediate synaptic neurotransmitter release, mucin secretion and other regulated exocytic processes1-4. For neurotransmitter release, the Ca2+ sensitivity is introduced by interactions between the Ca2+ sensor synaptotagmin and the SNARE complex5, and sequence conservation and functional studies suggest that this mechanism is also conserved for mucin secretion6. Disruption of Ca2+-triggered membrane fusion by a pharmacological agent would have therapeutic value for mucus hypersecretion as it is the major cause of airway obstruction in the pathophysiology of respiratory viral infection, asthma, chronic obstructive pulmonary disease and cystic fibrosis7-11. Here we designed a hydrocarbon-stapled peptide that specifically disrupts Ca2+-triggered membrane fusion by interfering with the so-called primary interface between the neuronal SNARE complex and the Ca2+-binding C2B domain of synaptotagmin-1. In reconstituted systems with these neuronal synaptic proteins or with their airway homologues syntaxin-3, SNAP-23, VAMP8, synaptotagmin-2, along with Munc13-2 and Munc18-2, the stapled peptide strongly suppressed Ca2+-triggered fusion at physiological Ca2+ concentrations. Conjugation of cell-penetrating peptides to the stapled peptide resulted in efficient delivery into cultured human airway epithelial cells and mouse airway epithelium, where it markedly and specifically reduced stimulated mucin secretion in both systems, and substantially attenuated mucus occlusion of mouse airways. Taken together, peptides that disrupt Ca2+-triggered membrane fusion may enable the therapeutic modulation of mucin secretory pathways.

Ultrasonography or Radiography for Suspected Pediatric Distal Forearm Fractures.

BACKGROUND: Data on whether ultrasonography for the initial diagnostic imaging of forearm fractures in children and adolescents is noninferior to radiography for subsequent physical function of the arm are limited. METHODS: In this open-label, multicenter, noninferiority, randomized trial in Australia, we recruited participants 5 to 15 years of age who presented to the emergency department with an isolated distal forearm injury, without a clinically visible deformity, in whom further evaluation with imaging was indicated. Participants were randomly assigned to initially undergo point-of-care ultrasonography or radiography, and were then followed for 8 weeks. The primary outcome was physical function of the affected arm at 4 weeks as assessed with the use of the validated Pediatric Upper Extremity Short Patient-Reported Outcomes Measurement Information System (PROMIS) score (range, 8 to 40, with higher scores indicating better function); the noninferiority margin was 5 points. RESULTS: A total of 270 participants were enrolled, with outcomes for 262 participants (97%) available at 4 weeks (with a window of ±3 days) as prespecified. PROMIS scores at 4 weeks in the ultrasonography group were noninferior to those in the radiography group (mean, 36.4 and 36.3 points, respectively; mean difference, 0.1 point; 95% confidence interval [CI], -1.3 to 1.4). Intention-to-treat analyses (in 266 participants with primary outcome data recorded at any time) produced similar results (mean difference, 0.1 point; 95% CI, -1.3 to 1.4). No clinically important fractures were missed, and there were no between-group differences in the occurrence of adverse events. CONCLUSIONS: In children and adolescents with a distal forearm injury, the use of ultrasonography as the initial diagnostic imaging method was noninferior to radiography with regard to the outcome of physical function of the arm at 4 weeks. (Funded by the Emergency Medicine Foundation and others; BUCKLED Australian New Zealand Clinical Trials Registry number, ACTRN12620000637943).

The Impact of Point-of-Care Ultrasound-Guided Resuscitation on Clinical Outcomes in Patients With Shock: A Systematic Review and Meta-Analysis.

OBJECTIVE: To determine the impact of point-of-care ultrasound (POCUS)-guided resuscitation on clinical outcomes in adult patients with shock. DATA SOURCE: We searched MEDLINE, Embase, and unpublished sources from inception to December 2023. STUDY SELECTION: We included randomized controlled trials (RCTs) that examined the use of POCUS to guide resuscitation in patients with shock. DATA EXTRACTION: We collected data regarding study and patient characteristics, POCUS protocol, control group interventions, and outcomes. DATA SYNTHESIS: We identified 18 eligible RCTs. POCUS slightly influences physicians' plans for IV fluid (IVF) and vasoactive medication prescription (moderate certainty), but results in little to no changes in the administration of IVF (low to high certainty) or inotropes (high certainty). POCUS may result in no change in the number of CT scans performed (low certainty) but probably reduces the number of diagnostic echocardiograms performed (moderate certainty). POCUS-guided resuscitation probably reduces 28-day mortality (relative risk [RR] 0.88; 95% CI, 0.78-0.99), the duration of vasoactive medication (mean difference -0.73 d; 95% CI, -1.16 to -0.30), and the need for renal replacement therapy (RRT) (RR 0.80; 95% CI, 0.63-1.02) (low to moderate certainty evidence), and lactate clearance (high certainty evidence). POCUS-guided resuscitation may results in little to no difference in ICU or hospital admissions, ICU and hospital length of stay, and the need for mechanical ventilation (MV) (low to moderate certainty evidence). There is an uncertain effect on the risk of acute kidney injury and the duration of MV or RRT (very low certainty evidence). CONCLUSIONS: POCUS-guided resuscitation in shock may yield important patient and health system benefits. Due to lack of sufficient evidence, we were unable to explore how the thresholds of operator competency, frequency, and timing of POCUS scans impact patient outcomes.

Diagnostic Accuracy of Point-of-Care Ultrasound Versus Radiographic Imaging for Pediatric Distal Forearm Fractures: A Randomized Controlled Trial.

STUDY OBJECTIVE: In patients aged 5 to 15 years with a clinically nondeformed distal forearm injury presenting to the emergency department (ED), we examined whether point-of-care ultrasound or radiographic imaging had better diagnostic accuracy, with the reference diagnosis determined by an expert panel review. METHODS: This multicenter, open-label, diagnostic randomized controlled trial was conducted in South East Queensland, Australia. Eligible patients were randomized to receive initial imaging through point-of-care ultrasound performed by an ED clinician or radiograph. Images were defined as "no," "buckle," or "other" fracture by the treating clinician. The primary outcome was the diagnostic accuracy of the treating clinician's interpretation compared against the reference standard diagnosis, which was determined retrospectively by an expert panel consisting of an emergency physician, pediatric radiologist, and pediatric orthopedic surgeon, who reviewed all imaging and follow-up. RESULTS: Two-hundred and seventy participants were enrolled, with 135 randomized to each initial imaging modality. There were 132 (97.8%) and 112 (83.0%) correctly diagnosed participants by ED clinicians in the point-of-care ultrasound and radiograph groups, respectively (absolute difference [AD]=14.8%; 95% confidence interval [CI] 8.0% to 21.6%; P<.001). Point-of-care ultrasound had better accuracy for participants with "buckle" fractures (AD=18.5%; 95% CI 7.1% to 29.8%) and "other" fractures (AD=17.1%; 95% CI 2.7% to 31.6%). No clinically important fractures were missed in either group. CONCLUSION: In children and adolescents presenting to the ED with a clinically nondeformed distal forearm injury, clinician-performed (acquired and interpreted) point-of-care ultrasound more accurately identified the correct diagnosis than clinician-interpreted radiographic imaging.

Statistically significant differences versus convincing evidence of real treatment effects: an analysis of the false positive risk for single-centre trials in anaesthesia.

BACKGROUND: The American Statistical Association has highlighted problems with null hypothesis significance testing and outlined alternative approaches that may 'supplement or even replace P-values'. One alternative is to report the false positive risk (FPR), which quantifies the chance the null hypothesis is true when the result is statistically significant. METHODS: We reviewed single-centre, randomised trials in 10 anaesthesia journals over 6 yr where differences in a primary binary outcome were statistically significant. We calculated a Bayes factor by two methods (Gunel, Kass). From the Bayes factor we calculated the FPR for different prior beliefs for a real treatment effect. Prior beliefs were quantified by assigning pretest probabilities to the null and alternative hypotheses. RESULTS: For equal pretest probabilities of 0.5, the median (inter-quartile range [IQR]) FPR was 6% (1-22%) by the Gunel method and 6% (1-19%) by the Kass method. One in five trials had an FPR ≥20%. For trials reporting P-values 0.01-0.05, the median (IQR) FPR was 25% (16-30%) by the Gunel method and 20% (16-25%) by the Kass method. More than 90% of trials reporting P-values 0.01-0.05 required a pretest probability >0.5 to achieve an FPR of 5%. The median (IQR) difference in the FPR calculated by the two methods was 0% (0-2%). CONCLUSIONS: Our findings suggest that a substantial proportion of single-centre trials in anaesthesia reporting statistically significant differences provide limited evidence of real treatment effects, or, alternatively, required an implausibly high prior belief in a real treatment effect. CLINICAL TRIAL REGISTRATION: PROSPERO (CRD42023350783).

Perioperative use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors for diabetes mellitus.

Type 2 diabetes mellitus is an increasingly common long-term condition, and suboptimal perioperative glycaemic control can lead to postoperative harms. The advent of new antidiabetic drugs, in particular glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors, has enabled perioperative continuation of these medicines, thus avoiding the harms of variable rate i.v. insulin infusions whilst providing glycaemic control. There are differences between medicines regulatory agencies and organisations on how these classes that are most often used to treat diabetes mellitus, (but also in the case of SGLT2 inhibitors chronic kidney disease and heart failure in those without diabetes) should be managed in the perioperative period. In this commentary, we argue that GLP-1 receptor agonists should continue during the perioperative period and that SGLT2 inhibitors should only be omitted the day prior to a planned procedure . The reasons for the differing advice advocated between regulatory agencies and what anaesthetic practitioners should do in the face of continuing uncertainty are discussed.

Patient-derived iPSCs link elevated mitochondrial respiratory complex I function to osteosarcoma in Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (RTS) is an autosomal recessive genetic disorder characterized by poikiloderma, small stature, skeletal anomalies, sparse brows/lashes, cataracts, and predisposition to cancer. Type 2 RTS patients with biallelic RECQL4 pathogenic variants have multiple skeletal anomalies and a significantly increased incidence of osteosarcoma. Here, we generated RTS patient-derived induced pluripotent stem cells (iPSCs) to dissect the pathological signaling leading to RTS patient-associated osteosarcoma. RTS iPSC-derived osteoblasts showed defective osteogenic differentiation and gain of in vitro tumorigenic ability. Transcriptome analysis of RTS osteoblasts validated decreased bone morphogenesis while revealing aberrantly upregulated mitochondrial respiratory complex I gene expression. RTS osteoblast metabolic assays demonstrated elevated mitochondrial respiratory complex I function, increased oxidative phosphorylation (OXPHOS), and increased ATP production. Inhibition of mitochondrial respiratory complex I activity by IACS-010759 selectively suppressed cellular respiration and cell proliferation of RTS osteoblasts. Furthermore, systems analysis of IACS-010759-induced changes in RTS osteoblasts revealed that chemical inhibition of mitochondrial respiratory complex I impaired cell proliferation, induced senescence, and decreased MAPK signaling and cell cycle associated genes, but increased H19 and ribosomal protein genes. In summary, our study suggests that mitochondrial respiratory complex I is a potential therapeutic target for RTS-associated osteosarcoma and provides future insights for clinical treatment strategies.

The use of Lentilactobacillus buchneri PJB1 and Lactiplantibacillus plantarum MTD1 on the ensiling of whole-plant corn silage, snaplage, and high-moisture corn.

Experiments were conducted over a 3-yr period to evaluate the effects of bacterial inoculants on the fermentation profile and aerobic stability of whole-plant corn silage (WPC), snaplage (SNA), and high-moisture corn (HMC). Whole-plant corn was inoculated with Lentilactobacillus buchneri PJB1 in combination with Lactiplantibacillus plantarum MTD1 or with Lpb. plantarum alone (experiments 1 and 2). Snaplage (experiment 3) and HMC (experiments 4 and 5) were inoculated with Len. buchneri in combination with Lpb. plantarum or with Len. buchneri alone. After inoculation, the feedstuffs were ensiled in 7.57-L silos and stored at 21 ± 2°C for 30 or 90 d. In experiment 5, silage was subjected to air stress for 2 h every 2 wk through 42 d and then for 2 h/wk until 90 d and had samples analyzed for their bacterial community composition by metagenomics. Overall, in all experiments, silages inoculated with Len. buchneri alone or in combination with Lpb. plantarum had more acetic acid and 1,2-propanediol and fewer yeasts than uninoculated silages. After 30 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum did not affect the aerobic stability of SNA, but it slightly increased the stability of WPC and markedly improved the stability of HMC. After 90 d of ensiling, inoculation with Len. buchneri alone or in combination with Lpb. plantarum markedly improved the aerobic stability of WPC, SNA, and HMC. In experiment 5, inoculation increased the relative abundance (RA) of Lactobacillaceae and reduced the RA of Enterobacteriaceae and Leuconostocaceae in HMC at 30 and 90 d and the RA of Clostridiaceae in non-air-stressed HMC at 90 d. Air-stressed HMC inoculated with Len. buchneri had less lactic acid, more acetic acid and 1,2-propanediol, and markedly greater aerobic stability than uninoculated air-stressed HMC at 90 d. In conclusion, inoculation with Len. buchneri PJB1 alone or in combination with Lpb. plantarum MTD1 increased the production of acetic acid and 1,2-propanediol, inhibited yeasts development, and improved the aerobic stability of WPC, SNA, and HMC. In HMC, inoculation markedly improved aerobic stability as soon as after 30 d of ensiling, and after 90 d, inoculation improved stability even under air stress conditions.

The Discovery of New Inhibitors of Insulin-Regulated Aminopeptidase by a High-Throughput Screening of 400,000 Drug-like Compounds.

With the ambition to identify novel chemical starting points that can be further optimized into small drug-like inhibitors of insulin-regulated aminopeptidase (IRAP) and serve as potential future cognitive enhancers in the clinic, we conducted an ultra-high-throughput screening campaign of a chemically diverse compound library of approximately 400,000 drug-like small molecules. Three biochemical and one biophysical assays were developed to enable large-scale screening and hit triaging. The screening funnel, designed to be compatible with high-density microplates, was established with two enzyme inhibition assays employing either fluorescent or absorbance readouts. As IRAP is a zinc-dependent enzyme, the remaining active compounds were further evaluated in the primary assay, albeit with the addition of zinc ions. Rescreening with zinc confirmed the inhibitory activity for most compounds, emphasizing a zinc-independent mechanism of action. Additionally, target engagement was confirmed using a complementary biophysical thermal shift assay where compounds causing positive/negative thermal shifts were considered genuine binders. Triaging based on biochemical activity, target engagement, and drug-likeness resulted in the selection of 50 qualified hits, of which the IC50 of 32 compounds was below 3.5 µM. Despite hydroxamic acid dominance, diverse chemotypes with biochemical activity and target engagement were discovered, including non-hydroxamic acid compounds. The most potent compound (QHL1) was resynthesized with a confirmed inhibitory IC50 of 320 nM. Amongst these compounds, 20 new compound structure classes were identified, providing many new starting points for the development of unique IRAP inhibitors. Detailed characterization and optimization of lead compounds, considering both hydroxamic acids and other diverse structures, are in progress for further exploration.

Metabolomic Profiling of the Effects of Dapagliflozin in Heart Failure With Reduced Ejection Fraction: DEFINE-HF.

BACKGROUND: Sodium-glucose cotransporter-2 inhibitors are foundational therapy in patients with heart failure with reduced ejection fraction (HFrEF), but underlying mechanisms of benefit are not well defined. We sought to investigate the relationships between sodium-glucose cotransporter-2 inhibitor treatment, changes in metabolic pathways, and outcomes using targeted metabolomics. METHODS: DEFINE-HF (Dapagliflozin Effects on Biomarkers, Symptoms and Functional Status in Patients With HF With Reduced Ejection Fraction) was a placebo-controlled trial of dapagliflozin in HFrEF. We performed targeted mass spectrometry profiling of 63 metabolites (45 acylcarnitines [markers of fatty acid oxidation], 15 amino acids, and 3 conventional metabolites) in plasma samples at randomization and 12 weeks. Using mixed models, we identified principal components analysis-defined metabolite clusters that changed differentially with treatment and examined the relationship between change in metabolite clusters and change in Kansas City Cardiomyopathy Questionnaire scores and NT-proBNP (N-terminal probrain natriuretic peptide). Models were adjusted for relevant clinical covariates and nominal P<0.05 with false discovery rate-adjusted P<0.10 was used to determine statistical significance. RESULTS: Among the 234 DEFINE-HF participants with targeted metabolomic data, the mean age was 62.0±11.1 years, 25% were women, 38% were Black, and mean ejection fraction was 27±8%. Dapagliflozin increased ketone-related and short-chain acylcarnitine as well as medium-chain acylcarnitine principal components analysis-defined metabolite clusters compared with placebo (nominal P=0.01, false discovery rate-adjusted P=0.08 for both clusters). However, ketosis (ß-hydroxybutyrate levels >500 µmol/L) was achieved infrequently (3 [2.5%] in dapagliflozin arm versus 1 [0.9%] in placebo arm) and supraphysiologic levels were not observed. Increases in long-chain acylcarnitine, long-chain dicarboxylacylcarnitine, and aromatic amino acid metabolite clusters were associated with decreases in Kansas City Cardiomyopathy Questionnaire scores (ie, worse quality of life) and increases in NT-proBNP levels, without interaction by treatment group. CONCLUSIONS: In this study of targeted metabolomics in a placebo-controlled trial of sodium-glucose cotransporter-2 inhibitors in HFrEF, we observed effects of dapagliflozin on key metabolic pathways, supporting a role for altered ketone and fatty acid biology with sodium-glucose cotransporter-2 inhibitors in patients with HFrEF. Only physiologic levels of ketosis were observed. In addition, we identified several metabolic biomarkers associated with adverse HFrEF outcomes. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02653482.

Health Status after Invasive or Conservative Care in Coronary and Advanced Kidney Disease.

BACKGROUND: In the ISCHEMIA-CKD trial, the primary analysis showed no significant difference in the risk of death or myocardial infarction with initial angiography and revascularization plus guideline-based medical therapy (invasive strategy) as compared with guideline-based medical therapy alone (conservative strategy) in participants with stable ischemic heart disease, moderate or severe ischemia, and advanced chronic kidney disease (an estimated glomerular filtration rate of <30 ml per minute per 1.73 m2 or receipt of dialysis). A secondary objective of the trial was to assess angina-related health status. METHODS: We assessed health status with the Seattle Angina Questionnaire (SAQ) before randomization and at 1.5, 3, and 6 months and every 6 months thereafter. The primary outcome of this analysis was the SAQ Summary score (ranging from 0 to 100, with higher scores indicating less frequent angina and better function and quality of life). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate the treatment effect with the invasive strategy. RESULTS: Health status was assessed in 705 of 777 participants. Nearly half the participants (49%) had had no angina during the month before randomization. At 3 months, the estimated mean difference between the invasive-strategy group and the conservative-strategy group in the SAQ Summary score was 2.1 points (95% credible interval, -0.4 to 4.6), a result that favored the invasive strategy. The mean difference in score at 3 months was largest among participants with daily or weekly angina at baseline (10.1 points; 95% credible interval, 0.0 to 19.9), smaller among those with monthly angina at baseline (2.2 points; 95% credible interval, -2.0 to 6.2), and nearly absent among those without angina at baseline (0.6 points; 95% credible interval, -1.9 to 3.3). By 6 months, the between-group difference in the overall trial population was attenuated (0.5 points; 95% credible interval, -2.2 to 3.4). CONCLUSIONS: Participants with stable ischemic heart disease, moderate or severe ischemia, and advanced chronic kidney disease did not have substantial or sustained benefits with regard to angina-related health status with an initially invasive strategy as compared with a conservative strategy. (Funded by the National Heart, Lung, and Blood Institute; ISCHEMIA-CKD ClinicalTrials.gov number, NCT01985360.).

Health-Status Outcomes with Invasive or Conservative Care in Coronary Disease.

BACKGROUND: In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS: We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS: At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS: In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline. (Funded by the National Heart, Lung, and Blood Institute and others; ISCHEMIA ClinicalTrials.gov number, NCT01471522.).

Association Between Change in Ambulatory Pulmonary Artery Pressures and Natriuretic Peptides in Patients with Heart Failure: Results From the EMBRACE-HF Trial.

BACKGROUND: Remote monitoring of pulmonary artery (PA) pressures and serial N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements guide heart failure (HF) treatment, but their association has yet to be described. METHODS AND RESULTS: In the Empagliflozin Evaluation by Measuring the Impact on Hemodynamics in Patients with Heart Failure (EMBRACE-HF) trial, patients with HF and a remote PA pressure monitoring device were randomized to empagliflozin vs placebo. PA diastolic pressures (PADP) and NT-proBNP levels were obtained at baseline and 6 and 12 weeks. We used linear mixed models to examine the association between change in PADP and change in NT-proBNP, adjusting for baseline covariates. Of 62 patients, the mean patient age was 66.2 years, and 63% were male. The mean baseline PADP was 21.8 ± 6.4 mm Hg, and the mean NT-proBNP was 1844.6 ± 2767.7 pg/mL. The mean change between baseline and averaged 6- and 12-week PADP was -0.4 ± 3.1 mm Hg, and the mean change between baseline and averaged 6- and 12-week NT-proBNP was -81.5 ± 878.6 pg/mL. In adjusted analyses, every 2-mm Hg decrease in PADP was associated with an NT-proBNP reduction of 108.9 pg/mL (95% confidence interval -4.3 to 222.0, P = .06). CONCLUSIONS: We observed that short-term decreases in ambulatory PADP seem to be associated with decreases in NT-proBNP. This finding may provide additional clinical context when tailoring treatment for patients with HF.

Emergency department presentations during the COVID-19 pandemic in Queensland (to June 2021): interrupted time series analysis.

OBJECTIVES: To assess emergency department (ED) presentation numbers in Queensland during the coronavirus disease 2019 (COVID-19) pandemic to mid-2021, a period of relatively low COVID-19 case numbers. DESIGN: Interrupted time series analysis. SETTING: All 105 Queensland public hospital EDs. MAIN OUTCOME MEASURES: Numbers of ED presentations during the COVID-19 lockdown period (11 March 2020 - 30 June 2020) and the period of easing restrictions (1 July 2020 - 30 June 2021), compared with pre-pandemic period (1 January 2018 - 10 March 2020), overall (daily numbers) and by Australasian Triage Scale (ATS; daily numbers) and selected diagnostic categories (cardiac, respiratory, mental health, injury-related conditions) and conditions (stroke, sepsis) (weekly numbers). RESULTS: During the lockdown period, the mean number of ED presentations was 19.4% lower (95% confidence interval, -20.9% to -17.9%) than during the pre-pandemic period (predicted mean number: 5935; actual number: 4786 presentations). The magnitudes of the decline and the time to return to predicted levels varied by ATS category and diagnostic group; changes in presentation numbers were least marked for ATS 1 and 2 (most urgent) presentations, and for presentations with cardiac conditions or stroke. Numbers remained below predicted levels during the 12-month post-lockdown period for ATS 5 (least urgent) presentations and presentations with mental health problems, respiratory conditions, or sepsis. CONCLUSIONS: The COVID-19 pandemic and related public restrictions were associated with profound changes in health care use. Pandemic plans should include advice about continuing to seek care for serious health conditions and health emergencies, and support alternative sources of care for less urgent health care needs.

Minimum false-positive risk of primary outcomes and impact of reducing nominal P-value threshold from 0.05 to 0.005 in anaesthesiology randomised clinical trials: a cross-sectional study.

BACKGROUND: Reproducibility of research is poor; this may be because many articles report statistically significant findings that are false positives. Two potential solutions are to lower the P-value for statistical significance testing from 0.05 to 0.005 and to report the minimum false-positive risk (minFPR). This study determined these metrics for randomised controlled trials (RCTs) in general anaesthesiology journals. METHODS: We identified superiority RCTs published between January 1, 2019 and March 15, 2021 from seven leading anaesthesia journals. P-values for primary outcomes were collected, and minFPRs for these outcomes were calculated using a formula assuming a 50% prior probability of an intervention being effective (minFPR50). The primary outcomes were the percentage of RCTs maintaining statistical significance at P<0.005 and minFPR50. RESULTS: We included 318 RCTs. P-values below 0.05 were reported in 205/318 (64%) of RCTs. Of these 205 RCTs, 119/205 (58%) maintained statistical significance at the P<0.005 threshold. The mean (standard deviation) minFPR50 was 22% (20). At P=0.005, the minFPR50 was approximately 5%. CONCLUSIONS: These proposed metrics aimed at mitigating reproducibility concerns would call a significant portion of the anaesthesiology literature into question. We found a minFPR of 22% and determined that 42% of primary outcomes would not maintain statistical significance if the P-value threshold changed from 0.05 to 0.005. These findings could partially explain the lack of reproducibility of research findings.

Minimum protamine dose required to neutralize heparin in cardiac surgery: a single-centre, prospective, observational cohort study.

PURPOSE: Excess protamine contributes to coagulopathy following cardiopulmonary bypass (CPB) and may increase blood loss and transfusion requirements. The primary aim of this study was to find the least amount of protamine necessary to neutralize residual heparin following CPB using the gold standard assays of anti-IIa and anti-Xa activity. Secondary objectives were to evaluate whether the post-CPB activated clotting time could be used as a surrogate marker for quantifying heparin neutralization. METHODS: Twenty-eight consecutive patients undergoing elective cardiac surgery were enrolled. Protamine administration was standardized through an infusion pump at 25 mg·min-1. Blood samples were withdrawn prior to and following administration of 150, 200, 250, and 300 mg protamine and analyzed for activated clotting time and anti-IIa and -Xa activity. RESULTS: Following a mean (standard deviation) cumulative heparin dose of 67,700 (19,400) units and a CPB duration of 113 (71) min, protamine requirements varied widely. Eight out of 25 (32%) patients showed complete neutralization of anti-IIa and -Xa activity at the first sampling point (150 mg protamine; protamine:heparin ratio, 0.3 [0.1]). A protamine:heparin ratio of 0.5 (0.2) was sufficient for heparin neutralization in > 90% of patients. After CPB, a low to mid-range activated clotting time correlated well with anti-IIa and -Xa activity. CONCLUSIONS: The protamine:heparin ratio required to neutralize residual unfractionated heparin (UFH) following CPB is variable. A protamine:heparin ratio of 0.3 was sufficient to neutralize UFH in some patients, while a ratio of 0.5 is sufficient to neutralize both residual anti-IIa and -Xa activity in most patients. Larger studies are necessary to confirm these findings and evaluate their clinical implications. STUDY REGISTRATION: ClinicalTrials.gov (NCT03787641); registered 26 December 2018.

RéSUMé: OBJECTIF: L'excès de protamine contribue à la coagulopathie après la circulation extracorporelle (CEC) et peut augmenter les pertes de sang et les besoins transfusionnels. L'objectif principal de cette étude était de déterminer la quantité minimale de protamine nécessaire pour neutraliser l'héparine résiduelle post-CEC en utilisant les tests de référence de l'activité anti-IIa et anti-Xa. Les objectifs secondaires consistaient à évaluer si le temps de coagulation activé post-CEC pouvait être utilisé comme marqueur de substitution pour quantifier la neutralisation de l'héparine. MéTHODE: Vingt-huit patients consécutifs bénéficiant d'une chirurgie cardiaque non urgente ont été recrutés. L'administration de protamine par une pompe à perfusion à 25 mg·min-1 a été normalisée. Des échantillons de sang ont été prélevés avant et après l'administration de 150, 200, 250 et 300 mg de protamine et analysés pour déterminer le temps de coagulation activé et l'activité anti-IIa et -Xa. RéSULTATS: Après une dose cumulative moyenne (écart type) d'héparine de 67 700 (19 400) unités et une durée de CEC moyenne de 113 (71) min, les besoins en protamine variaient considérablement. Huit patients sur 25 (32 %) ont affiché une neutralisation complète de l'activité anti-IIa et -Xa au premier point de prélèvement (150 mg de protamine; rapport protamine : héparine, 0,3 [0,1]). Un rapport protamine/héparine de 0,5 (0,2) était suffisant pour la neutralisation de l'héparine chez > 90 % des patients. Après la CEC, un temps de coagulation activé bas à moyen était bien corrélé avec l'activité anti-IIa et -Xa. CONCLUSION: Le rapport protamine : héparine nécessaire pour neutraliser l'héparine non fractionnée (HNF) résiduelle suivant une CEC est variable. Un rapport protamine : héparine de 0,3 était suffisant pour neutraliser l'HNF chez certains patients, tandis qu'un rapport de 0,5 est suffisant pour neutraliser à la fois l'activité résiduelle des anti-IIa et celle des anti-Xa chez la plupart des patients. Des études plus vastes sont nécessaires pour confirmer ces résultats et évaluer leurs implications cliniques. ENREGISTREMENT DE L'éTUDE: ClinicalTrials.gov (NCT03787641); enregistrée le 26 décembre 2018.

Interpreting frequentist hypothesis tests: insights from Bayesian inference.

Randomized controlled trials are one of the best ways of quantifying the effectiveness of medical interventions. Therefore, when the authors of a randomized superiority trial report that differences in the primary outcome between the intervention group and the control group are "significant" (i.e., P ≤ 0.05), we might assume that the intervention has an effect on the outcome. Similarly, when differences between the groups are "not significant," we might assume that the intervention does not have an effect on the outcome. Nevertheless, both assumptions are frequently incorrect.In this article, we explore the relationship that exists between real treatment effects and declarations of statistical significance based on P values and confidence intervals. We explain why, in some circumstances, the chance an intervention is ineffective when P ≤ 0.05 exceeds 25% and the chance an intervention is effective when P > 0.05 exceeds 50%.Over the last decade, there has been increasing interest in Bayesian methods as an alternative to frequentist hypothesis testing. We provide a robust but nontechnical introduction to Bayesian inference and explain why a Bayesian posterior distribution overcomes many of the problems associated with frequentist hypothesis testing.Notwithstanding the current interest in Bayesian methods, frequentist hypothesis testing remains the default method for statistical inference in medical research. Therefore, we propose an interim solution to the "significance problem" based on simplified Bayesian metrics (e.g., Bayes factor, false positive risk) that can be reported along with traditional P values and confidence intervals. We calculate these metrics for four well-known multicentre trials. We provide links to online calculators so readers can easily estimate these metrics for published trials. In this way, we hope decisions on incorporating the results of randomized trials into clinical practice can be enhanced, minimizing the chance that useful treatments are discarded or that ineffective treatments are adopted.

RéSUMé: Les études randomisées contrôlées constituent l'un des meilleurs moyens de quantifier l'efficacité des interventions médicales. Par conséquent, lorsque les autrices et auteurs d'une étude randomisée superiorité signalent que les différences dans le critère d'évaluation principal entre le groupe d'intervention et le groupe témoin sont « significatives ¼ (c.-à-d. P ≤ 0,05), nous pourrions supposer que l'intervention a un effet sur le critère d'évaluation. De même, lorsque les différences entre les groupes ne sont « pas significatives ¼, nous pourrions supposer que l'intervention n'a pas d'effet sur le critère d'évaluation. Pourtant, ces deux hypothèses s'avèrent souvent incorrectes.Dans cet article, nous explorons la relation qui existe entre les effets réels d'un traitement et les déclarations de signification statistique fondées sur les valeurs P et les intervalles de confiance. Nous expliquons pourquoi, dans certaines circonstances, la probabilité qu'une intervention soit inefficace lorsque P ≤ 0,05 dépasse 25 % et la probabilité qu'une intervention soit efficace lorsque P > 0,05 dépasse 50 %.Au cours de la dernière décennie, nous avons assisté à un intérêt croissant pour les méthodes bayésiennes comme alternative aux tests d'hypothèses fréquentistes. Nous proposons une introduction robuste mais non technique à l'inférence bayésienne et expliquons pourquoi une distribution postérieure bayésienne surmonte bon nombre des problèmes associés aux tests d'hypothèses fréquentistes.Malgré l'intérêt actuel pour les méthodes bayésiennes, les tests d'hypothèses fréquentistes restent la méthode par défaut pour l'inférence statistique en recherche médicale. Par conséquent, nous proposons une solution provisoire au « problème de signification ¼ basée sur des mesures bayésiennes simplifiées (par exemple, facteur de Bayes, risque de faux positifs) qui peuvent être rapportées en même temps que les mesures traditionnelles des valeurs P et des intervalles de confiance. Nous calculons ces paramètres pour quatre études multicentriques bien connues. Nous fournissons des liens vers des calculatrices en ligne afin que les lectrices et lecteurs puissent facilement estimer ces mesures pour les études publiées. De cette façon, nous espérons que les décisions sur l'intégration des résultats des études randomisées dans la pratique clinique pourront être améliorées, minimisant ainsi le risque que des traitements utiles soient rejetés ou que des traitements inefficaces soient adoptés.

Six hundred years of South American tree rings reveal an increase in severe hydroclimatic events since mid-20th century.

South American (SA) societies are highly vulnerable to droughts and pluvials, but lack of long-term climate observations severely limits our understanding of the global processes driving climatic variability in the region. The number and quality of SA climate-sensitive tree ring chronologies have significantly increased in recent decades, now providing a robust network of 286 records for characterizing hydroclimate variability since 1400 CE. We combine this network with a self-calibrated Palmer Drought Severity Index (scPDSI) dataset to derive the South American Drought Atlas (SADA) over the continent south of 12°S. The gridded annual reconstruction of austral summer scPDSI is the most spatially complete estimate of SA hydroclimate to date, and well matches past historical dry/wet events. Relating the SADA to the Australia-New Zealand Drought Atlas, sea surface temperatures and atmospheric pressure fields, we determine that the El Niño-Southern Oscillation (ENSO) and the Southern Annular Mode (SAM) are strongly associated with spatially extended droughts and pluvials over the SADA domain during the past several centuries. SADA also exhibits more extended severe droughts and extreme pluvials since the mid-20th century. Extensive droughts are consistent with the observed 20th-century trend toward positive SAM anomalies concomitant with the weakening of midlatitude Westerlies, while low-level moisture transport intensified by global warming has favored extreme rainfall across the subtropics. The SADA thus provides a long-term context for observed hydroclimatic changes and for 21st-century Intergovernmental Panel on Climate Change (IPCC) projections that suggest SA will experience more frequent/severe droughts and rainfall events as a consequence of increasing greenhouse gas emissions.

Defining major surgical complications using administrative data in Ontario: a validation study.

BACKGROUND: Although surgical complications are often included as an outcome of surgical research conducted using administrative data, little validation work has been performed. We sought to evaluate the diagnostic performance of an algorithm designed to capture major surgical complications using health administrative data. METHODS: This retrospective study included patients who underwent high-risk elective general surgery at a single institution in Ontario, Canada, from Sept. 1, 2016, to Sept. 1, 2017. Patients were identified for inclusion using the local operative database. Medical records were reviewed by trained clinicians to abstract postoperative complications. Data were linked to administrative data holdings, and a series of code-based algorithms were applied to capture a composite indicator of major surgical complications. We used sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy to evaluate the performance of our administrative data algorithm, as compared with data abstracted from the institutional charting system. RESULTS: The study included a total of 270 patients. According to the data from the chart audit, 55% of patients experienced at least 1 major surgical complication. Overall sensitivity, specificity, PPV, NPV and accuracy for the composite outcome was 72%, 80%, 82%, 70% and 76%, respectively. Diagnostic performance was poor for several of the individual complications. CONCLUSION: Our results showed that administrative data holdings can be used to capture a composite indicator of major surgical complications with adequate sensitivity and specificity. Additional work is required to identify suitable algorithms for several specific complications.