Regulation of airway smooth muscle contraction by PGE2

Protease-activated receptor 2 (PAR2)is the most abundant PAR in the human lung and is expressed in bronchial epithelium and smooth muscle. There are conflicting reports on the precise role of PAR2 in the airways and studies have shown it can induce both bronchoconstriction and bronchodilation effects. While PAR2 is present on airway smooth muscle cells, it has been suggested that the inhibitory effects of PAR2 in the airways could be mediated via endogenous prostanoids.Prostaglandin E2(PGE2)is the most abundantly produced prostanoid in the body andexerts its biological effects through activation of four prostanoid E receptors(EPRs). Activation of EP1and EP3Rspromotes airway inflammation and cough, whereas EP2and EP4Rsinducepotent bronchodilation (Aso et al. 2013; Sastre and del Pozo 2012; Tilley et al.2003), however, the precise cellular mechanisms underlying the effects of PGE2in airway smooth musclehave not been fully elucidated. The aims of this study were to: 1) investigate the mechanisms underlying PAR2 mediated relaxations in murine airway smooth muscle; 2) identifythe EP receptor subtype responsible for the inhibitoryeffects of PGE2in murine airway smooth muscle;3) examine the underlying cellular processesand possible roleof K+channels inPGE2-induced relaxationsof airway smooth muscleand4) investigate if PGE2affected calcium signalling in isolated airway smooth muscle cells. Isometric tension recordings were obtainedfrom murine bronchial rings and intracellular calcium measurements were recordedfrom isolated airway smooth muscle cells using confocal microscopy. Transcriptional expression ofEPRsubtypes in whole bronchial tissueand isolatedairway smooth muscle cellswas investigatedusing RT-PCR and RT-quantification was determinedusing qPCR. The key findings of this study were: 1)PAR2 activation elicited potent relaxation of bronchial rings pre-contracted with EFS and the cholinergic agonist CCh (1PM) via releaseof endogenous PGE2; 2) Exogenous application of PGE2relaxedbronchial rings in a concentration-dependent manner;3) The inhibitoryeffects ofPGE2were reduced in the presence of an EP2R antagonist but not an EP4Rantagonist;4) PGE2-induced inhibitionof EFS-evoked contractions were also reduced by an EP2R antagonist, but not an EP4R antagonist, however 7inhibitory effects of the EP4R antagonist were unmasked when it was applied in the presence of the EP2R antagonist;5) PGE2-induced relaxations of CCh and EFS-evoked contractions were reduced in the presence of the BK channel blocker,iberiotoxinbut not by the Kv7 channel blocker,XE-991;6) PGE2reduced the frequency and amplitude of CCh-induced calcium oscillations in isolated murine airway smooth muscle cells;7) These effects were mimicked by the EP2R agonist, (R)-Butaprost, the AC activator, forskolin,the exchange protein activated by cAMP (EPAC) activator, 007-AM,the PKA activator, 6-MB-cAMP, and were partially reduced by the PKA inhibitor, Rp-8-CPT-cAMP; 8) CCh-induced calcium oscillations were inhibited by the IP3R inhibitor, 2-APB, the RyRinhibitor, tetracaine and, to a lesser extent, removal of calcium from the extracellular solution; 9) Caffeine-induced calcium transients in isolated airway smooth muscle cells were not affected by addition of PGE2; 10) All EPR subtypes were expressed in whole bronchial tissue, but EP4R was not detected in isolated airway smooth muscle cells.Taken together, these data suggest a role for EP2Rs in PGE2-induced inhibition of cholinergic responses in murine airway smooth muscle. These effects may involve activation of BK channels and inhibition of calcium oscillations through upregulation of PKA, and possibly EPAC, to inhibit IP3R evoked calcium release

Identification of Post-cardiac Arrest Blood Pressure Thresholds Associated With Outcomes in Children: An ICU-Resuscitation Study

INTRODUCTION: Though early hypotension after pediatric in-hospital cardiac arrest (IHCA) is associated with inferior outcomes, ideal post-arrest blood pressure (BP) targets have not been established. We aimed to leverage prospectively collected BP data to explore the association of post-arrest BP thresholds with outcomes. We hypothesized that post-arrest systolic and diastolic BP thresholds would be higher than the currently recommended post-cardiopulmonary resuscitation BP targets and would be associated with higher rates of survival to hospital discharge. METHODS: We performed a secondary analysis of prospectively collected BP data from the first 24 h following return of circulation from index IHCA events enrolled in the ICU-RESUScitation trial (NCT02837497). The lowest documented systolic BP (SBP) and diastolic BP (DBP) were percentile-adjusted for age, height and sex. Receiver operator characteristic curves and cubic spline analyses controlling for illness category and presence of pre-arrest hypotension were generated exploring the association of lowest post-arrest SBP and DBP with survival to hospital discharge and survival to hospital discharge with favorable neurologic outcome (Pediatric Cerebral Performance Category of 1-3 or no change from baseline). Optimal cutoffs for post-arrest BP thresholds were based on analysis of receiver operator characteristic curves and spline curves. Logistic regression models accounting for illness category and pre-arrest hypotension examined the associations of these thresholds with outcomes. RESULTS: Among 693 index events with 0-6 h post-arrest BP data, identified thresholds were: SBP \u3e 10th percentile and DBP \u3e 50th percentile for age, sex and height. Fifty-one percent (n = 352) of subjects had lowest SBP above threshold and 50% (n = 346) had lowest DBP above threshold. SBP and DBP above thresholds were each associated with survival to hospital discharge (SBP: aRR 1.21 [95% CI 1.10, 1.33]; DBP: aRR 1.23 [1.12, 1.34]) and survival to hospital discharge with favorable neurologic outcome (SBP: aRR 1.22 [1.10, 1.35]; DBP: aRR 1.27 [1.15, 1.40]) (all p \u3c 0.001). CONCLUSIONS: Following pediatric IHCA, subjects had higher rates of survival to hospital discharge and survival to hospital discharge with favorable neurologic outcome when BP targets above a threshold of SBP \u3e 10th percentile for age and DBP \u3e 50th percentile for age during the first 6 h post-arrest

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Convalescent plasma in patients admitted to hospital with COVID-19 (RECOVERY): a randomised controlled, open-label, platform trial

SummaryBackground Azithromycin has been proposed as a treatment for COVID-19 on the basis of its immunomodulatoryactions. We aimed to evaluate the safety and efficacy of azithromycin in patients admitted to hospital with COVID-19.Methods In this randomised, controlled, open-label, adaptive platform trial (Randomised Evaluation of COVID-19Therapy [RECOVERY]), several possible treatments were compared with usual care in patients admitted to hospitalwith COVID-19 in the UK. The trial is underway at 176 hospitals in the UK. Eligible and consenting patients wererandomly allocated to either usual standard of care alone or usual standard of care plus azithromycin 500 mg once perday by mouth or intravenously for 10 days or until discharge (or allocation to one of the other RECOVERY treatmentgroups). Patients were assigned via web-based simple (unstratified) randomisation with allocation concealment andwere twice as likely to be randomly assigned to usual care than to any of the active treatment groups. Participants andlocal study staff were not masked to the allocated treatment, but all others involved in the trial were masked to theoutcome data during the trial. The primary outcome was 28-day all-cause mortality, assessed in the intention-to-treatpopulation. The trial is registered with ISRCTN, 50189673, and ClinicalTrials.gov, NCT04381936.Findings Between April 7 and Nov 27, 2020, of 16 442 patients enrolled in the RECOVERY trial, 9433 (57%) wereeligible and 7763 were included in the assessment of azithromycin. The mean age of these study participants was65·3 years (SD 15·7) and approximately a third were women (2944 [38%] of 7763). 2582 patients were randomlyallocated to receive azithromycin and 5181 patients were randomly allocated to usual care alone. Overall,561 (22%) patients allocated to azithromycin and 1162 (22%) patients allocated to usual care died within 28 days(rate ratio 0·97, 95% CI 0·87–1·07; p=0·50). No significant difference was seen in duration of hospital stay (median10 days [IQR 5 to >28] vs 11 days [5 to >28]) or the proportion of patients discharged from hospital alive within 28 days(rate ratio 1·04, 95% CI 0·98–1·10; p=0·19). Among those not on invasive mechanical ventilation at baseline, nosignificant difference was seen in the proportion meeting the composite endpoint of invasive mechanical ventilationor death (risk ratio 0·95, 95% CI 0·87–1·03; p=0·24).Interpretation In patients admitted to hospital with COVID-19, azithromycin did not improve survival or otherprespecified clinical outcomes. Azithromycin use in patients admitted to hospital with COVID-19 should be restrictedto patients in whom there is a clear antimicrobial indication

Effect of Physiologic Point-of-Care Cardiopulmonary Resuscitation Training on Survival With Favorable Neurologic Outcome in Cardiac Arrest in Pediatric ICUs: A Randomized Clinical Trial

Importance: Approximately 40% of children who experience an in-hospital cardiac arrest survive to hospital discharge. Achieving threshold intra-arrest diastolic blood pressure (BP) targets during cardiopulmonary resuscitation (CPR) and systolic BP targets after the return of circulation may be associated with improved outcomes. Objective: To evaluate the effectiveness of a bundled intervention comprising physiologically focused CPR training at the point of care and structured clinical event debriefings. Design, Setting, and Participants: A parallel, hybrid stepped-wedge, cluster randomized trial (Improving Outcomes from Pediatric Cardiac Arrest-the ICU-Resuscitation Project [ICU-RESUS]) involving 18 pediatric intensive care units (ICUs) from 10 clinical sites in the US. In this hybrid trial, 2 clinical sites were randomized to remain in the intervention group and 2 in the control group for the duration of the study, and 6 were randomized to transition from the control condition to the intervention in a stepped-wedge fashion. The index (first) CPR events of 1129 pediatric ICU patients were included between October 1, 2016, and March 31, 2021, and were followed up to hospital discharge (final follow-up was April 30, 2021). Intervention: During the intervention period (n = 526 patients), a 2-part ICU resuscitation quality improvement bundle was implemented, consisting of CPR training at the point of care on a manikin (48 trainings/unit per month) and structured physiologically focused debriefings of cardiac arrest events (1 debriefing/unit per month). The control period (n = 548 patients) consisted of usual pediatric ICU management of cardiac arrest. Main Outcomes and Measures: The primary outcome was survival to hospital discharge with a favorable neurologic outcome defined as a Pediatric Cerebral Performance Category score of 1 to 3 or no change from baseline (score range, 1 [normal] to 6 [brain death or death]). The secondary outcome was survival to hospital discharge. Results: Among 1389 cardiac arrests experienced by 1276 patients, 1129 index CPR events (median patient age, 0.6 [IQR, 0.2-3.8] years; 499 girls [44%]) were included and 1074 were analyzed in the primary analysis. There was no significant difference in the primary outcome of survival to hospital discharge with favorable neurologic outcomes in the intervention group (53.8%) vs control (52.4%); risk difference (RD), 3.2% (95% CI, -4.6% to 11.4%); adjusted OR, 1.08 (95% CI, 0.76 to 1.53). There was also no significant difference in survival to hospital discharge in the intervention group (58.0%) vs control group (56.8%); RD, 1.6% (95% CI, -6.2% to 9.7%); adjusted OR, 1.03 (95% CI, 0.73 to 1.47). Conclusions and Relevance: In this randomized clinical trial conducted in 18 pediatric intensive care units, a bundled intervention of cardiopulmonary resuscitation training at the point of care and physiologically focused structured debriefing, compared with usual care, did not significantly improve patient survival to hospital discharge with favorable neurologic outcome among pediatric patients who experienced cardiac arrest in the ICU. Trial Registration: ClinicalTrials.gov Identifier: NCT02837497

Association of CPR simulation program characteristics with simulated and actual performance during paediatric in-hospital cardiac arrest

AIM: To evaluate associations between characteristics of simulated point-of-care cardiopulmonary resuscitation (CPR) training with simulated and actual intensive care unit (ICU) CPR performance, and with outcomes of children after in-hospital cardiac arrest. METHODS: This is a pre-specified secondary analysis of the ICU-RESUScitation Project; a prospective, multicentre cluster randomized interventional trial conducted in 18 ICUs from October 2016-March 2021. Point-of-care bedside simulations with real-time feedback to allow multidisciplinary ICU staff to practice CPR on a portable manikin were performed and quality metrics (rate, depth, release velocity, chest compression fraction) were recorded. Actual CPR performance was recorded for children 37 weeks post-conceptual age to 18 years who received chest compressions of any duration, and included intra-arrest haemodynamics and CPR mechanics. Outcomes included survival to hospital discharge with favourable neurologic status. RESULTS: Overall, 18,912 point-of-care simulations were included. Simulation characteristics associated with both simulation and actual performance included site, participant discipline, and timing of simulation training. Simulation characteristics were not associated with survival with favourable neurologic outcome. However, participants in the top 3 sites for improvement in survival with favourable neurologic outcome were more likely to have participated in a simulation in the past month, on a weekday day, to be nurses, and to achieve targeted depth of compression and chest compression fraction goals during simulations than the bottom 3 sites. CONCLUSIONS: Point-of-care simulation characteristics were associated with both simulated and actual CPR performance. More recent simulation, increased nursing participation, and simulation training during daytime hours may improve CPR performance

Calcium Use during Paediatric In-hospital Cardiac Arrest is Associated with Worse Outcomes

AIM: To evaluate associations between calcium administration and outcomes among children with in-hospital cardiac arrest and among specific subgroups in which calcium use is hypothesized to provide clinical benefit. METHODS: This is a secondary analysis of observational data collected prospectively as part of the ICU-RESUScitation project. Children 37 weeks post-conceptual age to 18 years who received chest compressions in one of 18 intensive care units from October 2016-March 2021 were eligible. Data included child and event characteristics, pre-arrest laboratory values, pre- and intra-arrest haemodynamics, and outcomes. Outcomes included sustained return of spontaneous circulation (ROSC), survival to hospital discharge, and survival to hospital discharge with favourable neurologic outcome. A propensity score weighted cohort was used to evaluate associations between calcium use and outcomes. Subgroups included neonates, and children with hyperkalaemia, sepsis, renal insufficiency, cardiac surgery with cardiopulmonary bypass, and calcium-avid cardiac diagnoses. RESULTS: Of 1,100 in-hospital cardiac arrests, median age was 0.63 years (IQR 0.19, 3.81); 450 (41%) received calcium. Among the weighted cohort, calcium use was not associated with sustained ROSC (aOR, 0.87; CI95 0.61-1.24; p=0.445), but was associated with lower rates of both survival to hospital discharge (aOR, 0.68; CI95 0.52-0.89; p=0.005) and survival with favourable neurologic outcome at hospital discharge (aOR, 0.75; CI95 0.57-0.98; p=0.038). Among subgroups, calcium use was associated with lower rates of survival to hospital discharge in children with sepsis and renal insufficiency. CONCLUSIONS: Calcium use was common during paediatric in-hospital cardiac arrest and associated with worse outcomes at hospital discharge

Survival With Favorable Neurologic Outcome and Quality of Cardiopulmonary Resuscitation Following In-Hospital Cardiac Arrest in Children With Cardiac Disease Compared With Noncardiac Disease

OBJECTIVES: To assess associations between outcome and cardiopulmonary resuscitation (CPR) quality for in-hospital cardiac arrest (IHCA) in children with medical cardiac, surgical cardiac, or noncardiac disease. DESIGN: Secondary analysis of a multicenter cluster randomized trial, the ICU-RESUScitation Project (NCT02837497, 2016-2021). SETTING: Eighteen PICUs. PATIENTS: Children less than or equal to 18 years old and greater than or equal to 37 weeks postconceptual age receiving chest compressions (CC) of any duration during the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of 1,100 children with IHCA, there were 273 medical cardiac (25%), 383 surgical cardiac (35%), and 444 noncardiac (40%) cases. Favorable neurologic outcome was defined as no more than moderate disability or no worsening from baseline Pediatric Cerebral Performance Category at discharge. The medical cardiac group had lower odds of survival with favorable neurologic outcomes compared with the noncardiac group (48% vs 55%; adjusted odds ratio [aOR] [95% CI], aOR 0.59 [95% CI, 0.39-0.87], p = 0.008) and surgical cardiac group (48% vs 58%; aOR 0.64 [95% CI, 0.45-0.9], p = 0.01). We failed to identify a difference in favorable outcomes between surgical cardiac and noncardiac groups. We also failed to identify differences in CC rate, CC fraction, ventilation rate, intra-arrest average target diastolic or systolic blood pressure between medical cardiac versus noncardiac, and surgical cardiac versus noncardiac groups. The surgical cardiac group had lower odds of achieving target CC depth compared to the noncardiac group (OR 0.15 [95% CI, 0.02-0.52], p = 0.001). We failed to identify a difference in the percentage of patients achieving target CC depth when comparing medical cardiac versus noncardiac groups. CONCLUSIONS: In pediatric IHCA, medical cardiac patients had lower odds of survival with favorable neurologic outcomes compared with noncardiac and surgical cardiac patients. We failed to find differences in CPR quality between medical cardiac and noncardiac patients, but there were lower odds of achieving target CC depth in surgical cardiac compared to noncardiac patients

Outcomes and characteristics of cardiac arrest in children with pulmonary hypertension: A secondary analysis of the ICU-RESUS clinical trial

BACKGROUND: Previous studies have identified pulmonary hypertension (PH) as a relatively common diagnosis in children with in-hospital cardiac arrest (IHCA), and preclinical laboratory studies have found poor outcomes and low systemic blood pressures during CPR for PH-associated cardiac arrest. The objective of this study was to determine the prevalence of PH among children with IHCA and the association between PH diagnosis and intra-arrest physiology and survival outcomes. METHODS: This was a prospectively designed secondary analysis of patients enrolled in the ICU-RESUS clinical trial (NCT02837497). The primary exposure was a pre-arrest diagnosis of PH. The primary survival outcome was survival to hospital discharge with favorable neurologic outcome (Pediatric Cerebral Performance Category score 1-3 or unchanged from baseline). The primary physiologic outcome was event-level average diastolic blood pressure (DBP) during CPR. RESULTS: Of 1276 patients with IHCAs during the study period, 1129 index IHCAs were enrolled; 184 (16.3%) had PH and 101/184 (54.9%) were receiving inhaled nitric oxide at the time of IHCA. Survival with favorable neurologic outcome was similar between patients with and without PH on univariate (48.9% vs. 54.4%; p = 0.17) and multivariate analyses (aOR 0.82 [95%CI: 0.56, 1.20]; p = 0.32). There were no significant differences in CPR event outcome or survival to hospital discharge. Average DBP, systolic BP, and end-tidal carbon dioxide during CPR were similar between groups. CONCLUSIONS: In this prospective study of pediatric IHCA, pre-existing PH was present in 16% of children. Pre-arrest PH diagnosis was not associated with statistically significant differences in survival outcomes or intra-arrest physiologic measures