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Non-invasive respiratory support (NIRS) has increasingly been used in the management of COVID-19-associated acute respiratory failure, but questions remain about the utility, safety, and outcome benefit of NIRS strategies. We identified two randomised controlled trials and 83 observational studies, compromising 13 931 patients, that examined the effects of NIRS modalities-high-flow nasal oxygen, continuous positive airway pressure, and bilevel positive airway pressure-on patients with COVID-19. Of 5120 patients who were candidates for full treatment escalation, 1880 (37%) progressed to invasive mechanical ventilation and 3658 of 4669 (78%) survived to study end. Survival was 30% among the 1050 patients for whom NIRS was the stated ceiling of treatment. The two randomised controlled trials indicate superiority of non-invasive ventilation over high-flow nasal oxygen in reducing the need for intubation. Reported complication rates were low. Overall, the studies indicate that NIRS in patients with COVID-19 is safe, improves resource utilisation, and might be associated with better outcomes. To guide clinical decision making, prospective, randomised studies are needed to address timing of intervention, optimal use of NIRS modalities-alone or in combination-and validation of tools such as oxygenation indices, response to a trial of NIRS, and inflammatory markers as predictors of treatment success., Competing Interests: Declaration of interests MS and HEM were involved in the development of the UCL Ventura continuous positive airway pressure (CPAP) device, the manufacture of which was funded by the UK Department of Health and Social Care on a non-profit basis. MS chaired an educational webinar for Fisher & Paykel, which manufactures high-flow nasal oxygen devices. He reports grants, advisory board honoraria, and speaker's fees from Amormed, Apollo Therapeutics, Bayer, Baxter, Biotest, Critical Pressure, DSTL, General Electric, NewB, Roche Diagnostics, and Shionogi, outside of the submitted work. HEM consults for Scuba Travel International, which is developing a new closed-circuit, low-oxygen-use CPAP machine. The other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: Acute skeletal muscle wasting in critical illness is associated with excess morbidity and mortality. Continuous feeding may suppress muscle protein synthesis as a result of the muscle-full effect, unlike intermittent feeding, which may ameliorate it., Research Question: Does intermittent enteral feed decrease muscle wasting compared with continuous feed in critically ill patients?, Study Design and Methods: In a phase 2 interventional single-blinded randomized controlled trial, 121 mechanically ventilated adult patients with multiorgan failure were recruited following prospective informed consultee assent. They were randomized to the intervention group (intermittent enteral feeding from six 4-hourly feeds per 24 h, n = 62) or control group (standard continuous enteral feeding, n = 59). The primary outcome was 10-day loss of rectus femoris muscle cross-sectional area determined by ultrasound. Secondary outcomes included nutritional target achievements, plasma amino acid concentrations, glycemic control, and physical function milestones., Results: Muscle loss was similar between arms (-1.1% [95% CI, -6.1% to -4.0%]; P = .676). More intermittently fed patients received 80% or more of target protein (OR, 1.52 [1.16-1.99]; P < .001) and energy (OR, 1.59 [1.21-2.08]; P = .001). Plasma branched-chain amino acid concentrations before and after feeds were similar between arms on trial day 1 (71 μM [44-98 μM]; P = .547) and trial day 10 (239 μM [33-444 μM]; P = .178). During the 10-day intervention period the coefficient of variation for glucose concentrations was higher with intermittent feed (17.84 [18.6-20.4]) vs continuous feed (12.98 [14.0-15.7]; P < .001). However, days with reported hypoglycemia and insulin usage were similar in both groups. Safety profiles, gastric intolerance, physical function milestones, and discharge destinations did not differ between groups., Interpretation: Intermittent feeding in early critical illness is not shown to preserve muscle mass in this trial despite resulting in a greater achievement of nutritional targets than continuous feeding. However, it is feasible and safe., Trial Registry: ClinicalTrials.gov; No.: NCT02358512; URL: www.clinicaltrials.gov., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

The UK's Health System is in crisis, central funding no longer keeping pace with demand. Traditional responses-spending more, seeking efficiency savings or invoking market forces-are not solutions. The health of our nation demands urgent delivery of a radical new model, negotiated openly between public, policymakers and healthcare professionals. Such a model could focus on disease prevention, modifying health behaviour and implementing change in public policy in fields traditionally considered unrelated to health such as transport, food and advertising. The true cost-effectiveness of healthcare interventions must be balanced against the opportunity cost of their implementation, bolstering the central role of NICE in such decisions. Without such action, the prognosis for our healthcare system-and for the health of the individuals it serves-may be poor. Here, we explore such a new prescription for our national health., (© The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Cardiopulmonary exercise testing (CPET) measures peak exertional oxygen consumption ( V˙O2peak ) and that at the anaerobic threshold ( V˙O2 at AT, i.e. the point at which anaerobic metabolism contributes substantially to overall metabolism). Lower values are associated with excess postoperative morbidity and mortality. A reduced haemoglobin concentration ([Hb]) results from a reduction in total haemoglobin mass (tHb-mass) or an increase in plasma volume. Thus, tHb-mass might be a more useful measure of oxygen-carrying capacity and might correlate better with CPET-derived fitness measures in preoperative patients than does circulating [Hb]., Methods: Before major elective surgery, CPET was performed, and both tHb-mass (optimized carbon monoxide rebreathing method) and circulating [Hb] were determined., Results: In 42 patients (83% male), [Hb] was unrelated to V˙O2 at AT and V˙O2peak ( r =0.02, P =0.89 and r =0.04, P =0.80, respectively) and explained none of the variance in either measure. In contrast, tHb-mass was related to both ( r =0.661, P <0.0001 and r =0.483, P =0.001 for V˙O2 at AT and V˙O2peak , respectively). The tHb-mass explained 44% of variance in V˙O2 at AT ( P <0.0001) and 23% in V˙O2peak ( P =0.001)., Conclusions: In contrast to [Hb], tHb-mass is an important determinant of physical fitness before major elective surgery. Further studies should determine whether low tHb-mass is predictive of poor outcome and whether targeted increases in tHb-mass might thus improve outcome., (© The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com)

Background: Skeletal muscle impairment is a recognized complication of COPD, predicting mortality in severe disease. Increasing evidence implicates the renin-angiotensin system in control of muscle phenotype. We hypothesized that angiotensin-converting enzyme (ACE) inhibition would improve quadriceps function and exercise performance in COPD., Methods: This double-blind, randomized placebo-controlled trial investigated the effect of the ACE inhibitor, fosinopril, on quadriceps function in patients with COPD with quadriceps weakness. Primary outcomes were change in quadriceps endurance and atrophy signaling at 3 months. Quadriceps maximum voluntary contraction (QMVC), mid-thigh CT scan of the cross-sectional area (MTCSA), and incremental shuttle walk distance (ISWD) were secondary outcomes., Results: Eighty patients were enrolled (mean [SD], 65 [8] years, FEV1 43% [21%] predicted, 53% men). Sixty-seven patients (31 fosinopril, 36 placebo) completed the trial. The treatment group demonstrated a significant reduction in systolic BP (Δ-10.5 mm Hg; 95% CI, -19.9 to -1.1; P = .03) and serum ACE activity (Δ-20.4 IU/L; 95% CI, -31.0 to -9.8; P < .001) compared with placebo. No significant between-group differences were observed in the primary end points of quadriceps endurance half-time (Δ0.5 s; 95% CI, -13.3-14.3; P = .94) or atrogin-1 messenger RNA expression (Δ-0.03 arbitrary units; 95% CI, -0.32-0.26; P = .84). QMVC improved in both groups (fosinopril: Δ1.1 kg; 95% CI, 0.03-2.2; P = .045 vs placebo: Δ3.6 kg; 95% CI, 2.1-5.0; P < .0001) with a greater increase in the placebo arm (between-group, P = .009). No change was shown in the MTCSA (P = .09) or ISWD (P = .51)., Conclusions: This randomized controlled trial found that ACE inhibition, using fosinopril for 3 months, did not improve quadriceps function or exercise performance in patients with COPD with quadriceps weakness., Trial Registry: Current Controlled Trials; No.: ISRCTN05581879; URL: www.controlled-trials.com.

Background: For several types of non-cardiac surgery, the cardiopulmonary exercise testing (CPET)-derived variables anaerobic threshold (AT), peak oxygen consumption (VO2 peak), and ventilatory equivalent for CO(2) (VE/VCO2 ) are predictive of increased postoperative risk: less physically fit patients having a greater risk of adverse outcome. We investigated this relationship in patients undergoing gastric bypass surgery., Methods: All patients (<190 kg) who were referred for CPET and underwent elective gastric bypass surgery at the Whittington Hospital NHS Trust between September 1, 2009, and February 25, 2011, were included in the study (n=121). Fifteen patients did not complete CPET. CPET variables (VO2 peak, AT, and VE/VCO2 ) were derived for 106 patients. The primary outcome variables were day 5 morbidity and hospital length of stay (LOS). The independent t-test and Fisher's exact test were used to test for differences between surgical outcome groups. The predictive capacity of CPET markers was determined using receiver operating characteristic (ROC) curves., Results: The AT was lower in patients with postoperative complications than in those without [9.9 (1.5) vs 11.1 (1.7) ml kg(-1) min(-1), P=0.049] and in patients with a LOS>3 days compared with LOS ≤ 3 days [10.4 (1.4) vs 11.3 (1.8) ml kg(-1) min(-1), P=0.023]. ROC curve analysis identified AT as a significant predictor of LOS>3 days (AUC 0.640, P=0.030). The VO2 peak and VE/VCO2 were not associated with postoperative outcome., Conclusions: AT, determined using CPET, predicts LOS after gastric bypass surgery.

Background: A substantial proportion of patients suffer prolonged length of intensive care unit stay (PLOS) or prolonged mechanical ventilation (PMV) following coronary artery bypass grafting (CABG). Identifying factors associated with PLOS and PMV would aid in patient risk stratification. We sought to identify the factors associated with PLOS and PMV following CABG., Methods: Participants were patients undergoing first-time elective CABG. All were observed until discharge and clinical data were collected on a standardized proforma. PLOS and PMV were defined a priori as >2 days and >12 h respectively, based on centre norms., Results: Of the 439 patients in the study, 105 (23.9%) had PLOS and 111 (25.2%) had PMV. Independent predictors of PMV were age, diabetes, previous myocardial infarction (MI), New York Heart Association (NYHA) class and statin use. The only independent predictor of PLOS was the duration of preceding hypertension., Conclusion: The factors associated with PMV and PLOS in our study are easily attainable, routine clinical details and may be built into bed management algorithms. Confirmation of the association of preceding hypertension and subsequent investigation of the possible mechanism mediating this association, is suggested., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

Objective: To develop a tool for identifying and quantifying morbidity following cardiac surgery (cardiac postoperative morbidity score [C-POMS])., Study Design and Setting: Morbidity was prospectively assessed in 450 cardiac surgery patients on postoperative days 1, 3, 5, 8, and 15 using POMS criteria (nine postoperative morbidity domains in general surgical patients) and cardiac-specific variables (from expert panel). Other morbidities were noted as free text and included if prevalence was more than 5%, missingness less than 5%, and mean expert-rated severity-importance index score more than 8. Construct validity was assessed by expert panel review, Cronbach's alpha (internal consistency), and linear regression (predictive ability of C-POMS for length of stay [LOS])., Results: A 13-domain model was derived. Internal consistency (>0.7) on D3-D15 permits use as a summative score of total morbidity burden. Mean C-POMS scores were 3.4 (D3), 2.6 (D5), 3.4 (D8), and 3.8 (D15). Patient LOS was 4.6 days (P=0.012), 5.3 days (P=0.001), and 7.6 days (P=0.135) longer in patients with C-POMS-defined morbidity on D3, D5, D8, and D15, respectively, than in those without. For every unit increase in C-POMS summary score, subsequent LOS increased by 1.7 (D3), 2.2 (D5), 4.5 (D8), and 6.2 (D15) days (all P=0.000)., Conclusion: C-POMS is the first validated tool for identifying total morbidity burden after cardiac surgery. However, further external validation is warranted., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Large increases in inflammatory markers, particularly IL-6, occur after cardiac surgery. However, despite interventions to reduce the inflammatory response, great variability still remains which could in part be attributable to genetic predisposition. Since increased IL-6 levels following surgery are also associated with poorer outcome we sought to determine whether baseline and post-operative levels of Interleukin-6 (IL-6) and functional common variants of the Interleukin-6 (IL6) gene are associated with post-operative outcome following coronary artery bypass grafting (CABG). Caucasian patients undergoing first-time elective CABG were studied. IL-6 levels were measured pre-, 6h and 24h following surgery and genotypes for IL6 gene variants -174G>C and -572G>C were obtained. Clinical data was collected daily until patient discharge. Patient outcome was categorised as with (ICUC, n=177) and without (NICUC, n=189) a post-operative complication during the ICU period and with (POC, n=215) and without (NC, n=151) a post-operative complication during hospitalisation. IL-6 levels pre- and at 24h were greater in POC and ICUC than NC and NICUC, respectively. Pre- IL-6 levels independently predicted (for 1 standard deviation increase in log IL-6) POC (OR 1.4, 95% CI 1.1-1.7, p=0.008) and ICUC (OR 1.3, 95% CI 1.0-1.6, p=0.02) outcomes. Overall, the IL6-572G>C had an effect over time on IL-6 levels (p=0.04) and on IL-6 levels in NC (P=0.008) and NICUC (p=0.006). However, no associations were found with the IL6 -572G>C or -174G>C variants on IL-6 levels at individual time-points or by outcome group. Thus, in conclusion, elevated pre-operative IL-6 levels, but not IL6 gene variants predict poor patient outcome following CABG.

Objectives: Adipose tissue is able to secrete a variety of active mediators into the circulation. One of these is Interleukin 6 (IL6). IL6 may play a causal role in the development of atherosclerosis. It has therefore been suggested that IL6 may form part of the link between obesity and vascular disease. The aim of this study was to quantify the relative IL6 expression in adipose tissue compared to other tissues., Methods: Tissue (vein, fat, muscle, blood) was collected from 32 patients undergoing varicose vein surgery. RNA was extracted and mRNA measured using RT-PCR relative quantification. The mean relative IL6 mRNA levels were compared between tissues using the Mann Whitney U test and the independent t-test. Tissue levels were compared for individuals using the Wilcoxon signed rank test., Results: Mean relative IL6 mRNA levels (mean+/-SEM) were significantly greater in adipose tissue 44.8+/-16.1 than in other tissues (leukocytes 1.1+/-0.3, vein 2.0+/-0.8, muscle 0.06+/-0.03: p<0.001). mRNA expression levels were also significantly higher in fat than in all other tissue types in individuals (p<0.001)., Conclusions: IL6 mRNA expression is significantly higher in adipose than in many other tissues known to express IL6.

Background: Left ventricular mass is a risk factor for cardiovascular morbidity and mortality. Although factors associated with elevated left ventricular mass have been sought and studied extensively in elderly and in diseased subjects, few studies have examined the young and healthy. The aim of this study was to examine the possible influence of lifestyle on left ventricular mass in a large group of young men., Methods: Left ventricular mass was assessed using cardiovascular magnetic resonance in 541 healthy Caucasian male army recruits. Anthropometric, lifestyle and blood pressure data were collected., Results: Mean unadjusted left ventricular mass and left ventricular mass indexed to body surface area were 163.8+/-24.9 g and 86.6+/-10.2 g m(-2) respectively. In univariate analysis, age, height, weight, alcohol consumption, systolic blood pressure, diastolic blood pressure and indices of physical activity were positively associated with unadjusted left ventricular mass (all P<0.02). By contrast, smoking was associated with lower mean left ventricular mass; never smoked 167.5+/-25.8 g vs ex-smokers 159.1+/-25.2 g vs current smokers 161.0+/-23.1 g (P=0.007). Multivariate analysis revealed weight, systolic blood pressure, smoking status and indices of physical activity to be independent predictors of left ventricular mass., Conclusions: Our data confirm an association of age, body weight, height, physical activity, diastolic and systolic blood pressure with left ventricular mass. In addition, unexpectedly, we have found smoking is associated with lower left ventricular mass in a large sample of young healthy men. Although the latter association may result from confounding effects, such an interesting observation deserves further investigation.

Lipoprotein-associated PLA2 (Lp-PLA2) hydrolyses the sn-2 position of glycerophospholipids, in particular platelet activating factor (PAF), generating significant amounts of Lyso-PAF which in turn, via a remodelling pathway, can generate arachidonic acid (AA) from alkyl-acyl-glycerophosphorylcholine. AA is a precursor for prostaglandin synthesis, which regulates adipogenesis through the peroxisome proliferator-activated receptor subfamily. AA may also modulate skeletal muscle growth. We investigated the association of the PLA2G7 A379V variant with changes in body composition in a longitudinal study of 123 male Caucasian army recruits over 10 weeks of intensive physical training. There was no effect of genotype on baseline measures. However, after exercise training, homozygosity for the 379V allele was associated with a decrease in percentage adipose tissue mass (-3.61+/-1.14%), compared to AV (-1.67+/-0.38%) and AA (-1.09+/-0.24%) genotypes (p=0.01), and a significant mean increase (3.51+/-1.17%) in percentage lean mass, compared to AV (1.64+/-0.38%) and AA (1.10+/-0.24%) recruits (p=0.02). The association of this genotype with changes in body composition after training suggests a novel role for Lp-PLA2.

Introduction: The tissue renin-angiotensin system is implicated in the pathogenesis of coronary artery disease (CAD). As locally synthesised aldosterone is a potential mediator of CAD, we have sought an association of the -344T>C variant of the aldosterone synthase (CYP11B2) gene with CAD events., Methods: Subjects comprised of the Second Northwick Park Heart Study (NPHSII), a prospective study of unrelated, healthy middle-aged Caucasian males. CAD events were recorded in 2490 subjects, and defined as a sudden cardiac death, myocardial infarction or coronary artery revascularisation procedure. Mean follow-up was 10.8 years. Aldosterone synthase genotype was determined in 2490 subjects. Power calculation suggests that we have 80% power (at a significance level of 0.05) to detect a difference in hazard ratio (HR) between homozygote groups of 0.45., Results: One hundred and eighty-seven CAD events were recorded in 2490 subjects. In the group overall, CAD events were independent of genotype with adjusted hazard ratios being 1.00 versus 1.25 versus 0.80 for TT versus TC versus CC genotypes, respectively, P = 0.07. Genotype interactions with smoking and blood pressure were sought. Whilst CAD events were independent of genotype amongst non-smokers, CC genotype in smokers was associated with a reduced risk HR 2.02 versus 2.28 versus 0.82 for TT versus TC versus CC genotypes, P = 0.05 (HR for TT + TC versus CC were 1.77 versus 0.67, P = 0.02). This apparent interaction remained after adjustment for conventional risk factors. No such interaction was found with blood pressure., Conclusions: Aldosterone synthase genotype is unrelated to overall CAD events risk. A possible interaction with smoking requires confirmation.