Ethnicity and Observed Oxygen Saturations, Fraction of Inspired Oxygen, and Clinical Outcomes: A Post Hoc Analysis of the Oxy-PICU Trial of Conservative Oxygenation.

OBJECTIVES: A conservative oxygenation strategy, targeting peripheral oxygen saturations (Spo2) between 88% and 92% in mechanically ventilated children in PICU, was associated with a shorter duration of organ support and greater survival compared with Spo2 greater than 94% in our recent Oxy-PICU trial. Spo2 monitors may overestimate arterial oxygen saturation (Sao2) in patients with higher levels of skin pigmentation compared with those with less skin pigmentation. We investigated if ethnicity was associated with changes in distributions of Spo2 and Fio2 and outcome. DESIGN: Post hoc analysis of a pragmatic, open-label, multicenter randomized controlled trial. SETTING: Fifteen PICUs across the United Kingdom and Scotland. PATIENTS: Children aged 38 weeks corrected gestational age to 15 years accepted to a participating PICU as an unplanned admission and receiving invasive mechanical ventilation with supplemental oxygen for abnormal gas exchange. METHODS: Hierarchical regression models for Spo2 and Fio2, and ordinal models for the primary trial outcome of a composite of the duration of organ support at 30 days and death, were used to examine the effects of ethnicity, accounting for baseline Spo2, Fio2, and mean airway pressure and trial allocation. MEASUREMENTS AND MAIN RESULTS: Ethnicity data were available for 1577 of 1986 eligible children, 1408 (89.3%) of which were White, Asian, or Black. Spo2 and Fio2 distributions did not vary according to Black or Asian ethnicity compared with White children. The trial primary outcome measure also did not vary significantly with ethnicity. The point estimate for the treatment effect of conservative oxygenation in Black children was 0.64 (95% CI, 0.33-1.25) compared with 0.84 (0.68-1.04) in the overall trial population. CONCLUSIONS: These data do not suggest that the association between improved outcomes and conservative oxygenation strategy in mechanically ventilated children in PICU is modified by ethnicity.

Impact of High Dose Early Mobilization on Outcomes for Patients with Diabetes: A Secondary Analysis of the TEAM Trial.

RATIONALE: Patients with diabetes represent almost 20% of all ICU admissions and might respond differently to high dose early active mobilization. OBJECTIVES: To assess whether diabetes modified the relationship between the dose of early mobilization on clinical outcomes in the TEAM trial. METHODS: All TEAM trial patients were included. The primary outcome was days alive and out of hospital at day 180. Secondary outcomes included 180-day mortality and long-term functional outcomes at day 180. Logistic and median regression models were used to explore the effect of high dose early mobilization on outcomes by diabetes status. MEASUREMENTS AND MAIN RESULTS: All 741 patients from the original trial were included. Of these, 159 patients (21.4%) had diabetes. Patients with diabetes had a lower number of days alive and out of hospital at day 180 (124 [0-153] vs. 147 [82-164], p = 0.013), and higher 180-day mortality (30% vs. 18%, p = 0.044). In patients receiving high dose early mobilization, days alive and out of hospital at day 180 was 73.0 (0.0 - 144.5) in patients with diabetes and 146.5 (95.8 - 163.0) in patients without diabetes (p for interaction = 0.108). However, in patients with diabetes, high dose early mobilization increased the odds of mortality at 180 days (adjusted odds ratio 3.47; 95% confidence interval [CI], 1.67-7.61, p value for interaction, 0.001). CONCLUSIONS: In this secondary analysis of the TEAM trial, in patients with diabetes, a high dose early mobilization strategy did not significantly decrease the number of days alive and out of hospital at day 180 but it increased 180-day mortality.

Evaluating the clinical and cost-effectiveness of a conservative approach to oxygen therapy for invasively ventilated adults in intensive care: Protocol for the UK-ROX trial.

Background: In the United Kingdom, around 184,000 adults are admitted to an intensive care unit (ICU) each year with over 30% receiving mechanical ventilation. Oxygen is the commonest therapeutic intervention provided to these patients but it is unclear how much oxygen should be administered for the best clinical outcomes. Methods: The UK-ROX trial will evaluate the clinical and cost-effectiveness of conservative oxygen therapy (the minimum oxygen concentration required to maintain an oxygen saturation of 90% ± 2%) versus usual oxygen therapy in critically ill adults receiving supplemental oxygen when invasively mechanically ventilated in ICUs in England, Wales and Northern Ireland. The trial will recruit 16,500 patients from approximately 100 UK adult ICUs. Using a deferred consent model, enrolled participants will be randomly allocated (1:1) to conservative or usual oxygen therapy until ICU discharge or 90 days after randomisation. Objectives: The primary clinical outcome is all cause mortality at 90 days following randomisation. Discussion: The UK-ROX trial has received ethical approval from the South Central - Oxford C Research Ethics Committee (Reference: 20/SC/0423) and the Confidentiality Advisory Group (Reference: 22/CAG/0154). The trial commenced in May 2021 and, at the time of publication, 95 sites had opened to recruitment.

Conservative versus liberal oxygenation targets in critically ill children (Oxy-PICU): a UK multicentre, open, parallel-group, randomised clinical trial.

BACKGROUND: The optimal target for systemic oxygenation in critically ill children is unknown. Liberal oxygenation is widely practiced, but has been associated with harm in paediatric patients. We aimed to evaluate whether conservative oxygenation would reduce duration of organ support or incidence of death compared to standard care. METHODS: Oxy-PICU was a pragmatic, multicentre, open-label, randomised controlled trial in 15 UK paediatric intensive care units (PICUs). Children admitted as an emergency, who were older than 38 weeks corrected gestational age and younger than 16 years receiving invasive ventilation and supplemental oxygen were randomly allocated in a 1:1 ratio via a concealed, central, web-based randomisation system to conservative peripheral oxygen saturations ([SpO2] 88-92%) or liberal (SpO2 >94%) targets. The primary outcome was the duration of organ support at 30 days following random allocation, a rank-based endpoint with death either on or before day 30 as the worst outcome (a score equating to 31 days of organ support), with survivors assigned a score between 1 and 30 depending on the number of calendar days of organ support received. The primary effect estimate was the probabilistic index, a value greater than 0·5 indicating more than 50% probability that conservative oxygenation is superior to liberal oxygenation for a randomly selected patient. All participants in whom consent was available were included in the intention-to-treat analysis. The completed study was registered with the ISRCTN registry (ISRCTN92103439). FINDINGS: Between Sept 1, 2020, and May 15, 2022, 2040 children were randomly allocated to conservative or liberal oxygenation groups. Consent was available for 1872 (92%) of 2040 children. The conservative oxygenation group comprised 939 children (528 [57%] of 927 were female and 399 [43%] of 927 were male) and the liberal oxygenation group included 933 children (511 [56%] of 920 were female and 409 [45%] of 920 were male). Duration of organ support or death in the first 30 days was significantly lower in the conservative oxygenation group (probabilistic index 0·53, 95% CI 0·50-0·55; p=0·04 Wilcoxon rank-sum test, adjusted odds ratio 0·84 [95% CI 0·72-0·99]). Prespecified adverse events were reported in 24 (3%) of 939 patients in the conservative oxygenation group and 36 (4%) of 933 patients in the liberal oxygenation group. INTERPRETATION: Among invasively ventilated children who were admitted as an emergency to a PICU receiving supplemental oxygen, a conservative oxygenation target resulted in a small, but significant, greater probability of a better outcome in terms of duration of organ support at 30 days or death when compared with a liberal oxygenation target. Widespread adoption of a conservative oxygenation saturation target (SpO2 88-92%) could help improve outcomes and reduce costs for the sickest children admitted to PICUs. FUNDING: UK National Institute for Health and Care Research Health Technology Assessment Programme.

The effect of conservative oxygen therapy on mortality in adult critically ill patients: A systematic review and meta-analysis of randomised controlled trials.

Background: Oxygen is the commonest intervention provided to critically ill patients requiring mechanical ventilation. Despite this, it is unclear how much oxygen should be administered to patients in order to promote the best clinical outcomes and it has been suggested that a strategy of conservative oxygen therapy (COT) may be advantageous. We therefore sought to answer the question of whether COT versus usual or liberal oxygen therapy was beneficial to adult patients receiving mechanical ventilation on an intensive care unit (ICU) by performing a systematic review and meta-analysis. Methods: Studies were included if they were randomised controlled trials comparing COT to liberal or usual oxygen therapy strategies in acutely ill adults (aged ⩾18 years) admitted to an ICU, and reported an outcome of interest. Studies were excluded if they were limited to a specific single disease diagnosis. The review was registered on PROSPERO (CRD42022308436). Risk of bias was assessed using a modified Cochrane Risk of Bias assessment tool. Effect estimates were pooled using a random effects model with the between study variance estimated using restricted maximum likelihood and standard errors calculated using the method of Hartung-Knapp/Sidik-Jonkman. Between study heterogeneity was quantified using the I2 statistic. The certainty in the body of evidence was assessed using GRADE criteria. Results: Nine eligible studies with 5727 participants fulfilled all eligibility criteria. Trials varied in their definitions of COT and liberal or usual oxygen therapy. The pooled estimate of risk ratio for 90 day mortality for COT versus comparator was 0.99 (95% confidence interval 0.88-1.12, 95% prediction interval 0.82-1.21). There was low heterogeneity among studies (I2 = 22.4%). The finding that mortality was similar for patients managed with COT or usual/liberal oxygen therapy was graded as moderate certainty. Conclusions: In critically ill adults admitted to an ICU, COT is neither beneficial nor harmful when compared to usual or liberal oxygen therapy. Trials to date have been inconsistent in defining both COT and liberal or usual oxygen therapy, which may have had an impact on the results of this meta-analysis. Future research should focus on unifying definitions and outcome measures.

Randomised trial of the clinical and cost effectiveness of a supraglottic airway device compared with tracheal intubation for in-hospital cardiac arrest (AIRWAYS-3): Protocol, design and implementation.

Survival from in-hospital cardiac arrest is approximately 18%, but for patients who require advanced airway management survival is lower. Those who do survive are often left with significant disability. Traditionally, resuscitation of cardiac arrest patients has included tracheal intubation, however insertion of a supraglottic airway has gained popularity as an alternative approach to advanced airway management. Evidence from out-of-hospital cardiac arrest suggests no significant differences in mortality or morbidity between these two approaches, but there is no randomised evidence for airway management during in-hospital cardiac arrest. The aim of the AIRWAYS-3 randomised trial, described in this protocol paper, is to determine the clinical and cost effectiveness of a supraglottic airway versus tracheal intubation during in-hospital cardiac arrest. Patients will be allocated randomly to receive either a supraglottic airway or tracheal intubation as the initial advanced airway management. We will also estimate the relative cost-effectiveness of these two approaches. The primary outcome is functional status, measured using the modified Rankin Scale at hospital discharge or 30 days post-randomisation, whichever occurs first. AIRWAYS-3 presents ethical challenges regarding patient consent and data collection. These include the enrolment of unconscious patients without prior consent in a way that avoids methodological bias. Other complexities include the requirement to randomise patients efficiently during a time-critical cardiac arrest. Many of these challenges are encountered in other emergency care research; we discuss our approaches to addressing them. Trial registration: ISRCTN17720457. Prospectively registered on 29/07/2022.

Long-term effects of restriction of intravenous fluid in adult ICU patients with septic shock.

PURPOSE: To assess long-term outcomes of restrictive versus standard intravenous (IV) fluid therapy in adult intensive care unit (ICU) patients with septic shock included in the European Conservative versus Liberal Approach to Fluid Therapy in Septic Shock in Intensive Care (CLASSIC) trial. METHODS: We conducted the pre-planned analyses of mortality, health-related quality of life (HRQoL) using EuroQol (EQ)-5D-5L index values and EQ visual analogue scale (VAS), and cognitive function using Mini Montreal Cognitive Assessment (Mini MoCA) test at 1 year. Deceased patients were assigned numerical zero for HRQoL as a state equal to death and zero for cognitive function outcomes as worst possible score, and we used multiple imputation for missing data on HRQoL and cognitive function. RESULTS: Among 1554 randomized patients, we obtained 1-year data on mortality in 97.9% of patients, HRQoL in 91.3%, and cognitive function in 86.3%. One-year mortality was 385/746 (51.3%) in the restrictive-fluid group versus 383/767 (49.9%) in the standard-fluid group, absolute risk difference 1.5%-points [99% confidence interval (CI) - 4.8 to 7.8]. Mean differences were 0.00 (99% CI - 0.06 to 0.05) for EQ-5D-5L index values, - 0.65 for EQ VAS (- 5.40 to 4.08), and - 0.14 for Mini MoCA (- 1.59 to 1.14) for the restrictive-fluid group versus the standard-fluid group. The results for survivors only were similar in both groups. CONCLUSIONS: Among adult ICU patients with septic shock, restrictive versus standard IV fluid therapy resulted in similar survival, HRQoL, and cognitive function at 1 year, but clinically important differences could not be ruled out.

Regional citrate anticoagulation versus systemic heparin anticoagulation for continuous kidney replacement therapy in intensive care.

PURPOSE: Many intensive care units (ICUs) have transitioned from systemic heparin anticoagulation (SHA) to regional citrate anticoagulation (RCA) for continuous kidney replacement therapy (CKRT). We evaluated the clinical and health economic impacts of ICU transition to RCA. MATERIALS AND METHODS: We surveyed all adult general ICUs in England and Wales to identify transition dates and conducted a micro-costing study in eight ICUs. We then conducted an interrupted time-series analysis of linked, routinely collected health records. RESULTS: In 69,001 patients who received CKRT (8585 RCA, 60,416 SHA) in 181 ICUs between 2009 and 2017, transition to RCA was not associated with a change in 90-day mortality (adjusted odds ratio 0.98, 95% CI 0.89-1.08) but was associated with step-increases in duration of kidney support (0.53 days, 95% CI 0.28-0.79), advanced cardiovascular support (0.23 days, 95% CI 0.09-0.38) and ICU length of stay (0.86 days, 95% CI 0.24-1.49). The estimated one-year incremental net monetary benefit per patient was £ - 2376 (95% CI £ - 3841-£ - 911), with an estimated likelihood of cost-effectiveness of <0.1%. CONCLUSIONS: Transition to RCA was associated with significant increases in healthcare resource use, without corresponding clinical benefit, and is highly unlikely to be cost-effective over a one-year time horizon.

Early Active Mobilization during Mechanical Ventilation in the ICU.

BACKGROUND: Intensive care unit (ICU)-acquired weakness often develops in patients who are undergoing invasive mechanical ventilation. Early active mobilization may mitigate ICU-acquired weakness, increase survival, and reduce disability. METHODS: We randomly assigned 750 adult patients in the ICU who were undergoing invasive mechanical ventilation to receive increased early mobilization (sedation minimization and daily physiotherapy) or usual care (the level of mobilization that was normally provided in each ICU). The primary outcome was the number of days that the patients were alive and out of the hospital at 180 days after randomization. RESULTS: The median number of days that patients were alive and out of the hospital was 143 (interquartile range, 21 to 161) in the early-mobilization group and 145 days (interquartile range, 51 to 164) in the usual-care group (absolute difference, -2.0 days; 95% confidence interval [CI], -10 to 6; P = 0.62). The mean (±SD) daily duration of active mobilization was 20.8±14.6 minutes and 8.8±9.0 minutes in the two groups, respectively (difference, 12.0 minutes per day; 95% CI, 10.4 to 13.6). A total of 77% of the patients in both groups were able to stand by a median interval of 3 days and 5 days, respectively (difference, -2 days; 95% CI, -3.4 to -0.6). By day 180, death had occurred in 22.5% of the patients in the early-mobilization group and in 19.5% of those in the usual-care group (odds ratio, 1.15; 95% CI, 0.81 to 1.65). Among survivors, quality of life, activities of daily living, disability, cognitive function, and psychological function were similar in the two groups. Serious adverse events were reported in 7 patients in the early-mobilization group and in 1 patient in the usual-care group. Adverse events that were potentially due to mobilization (arrhythmias, altered blood pressure, and desaturation) were reported in 34 of 371 patients (9.2%) in the early-mobilization group and in 15 of 370 patients (4.1%) in the usual-care group (P = 0.005). CONCLUSIONS: Among adults undergoing mechanical ventilation in the ICU, an increase in early active mobilization did not result in a significantly greater number of days that patients were alive and out of the hospital than did the usual level of mobilization in the ICU. The intervention was associated with increased adverse events. (Funded by the National Health and Medical Research Council of Australia and the Health Research Council of New Zealand; TEAM ClinicalTrials.gov number, NCT03133377.).

Renal replacement anticoagulant management: Protocol and analysis plan for an observational comparative effectiveness study of linked data sources.

Acute kidney injury is common in critical illness. In patients with severe acute kidney injury, renal replacement therapy is needed to prevent harm from metabolic and electrolyte disturbances and fluid overload. In the UK, continuous renal replacement therapy (CRRT) is the preferred modality, which requires anticoagulation. Over the last decade, conventional systemic heparin anticoagulation has started being replaced by regional citrate anticoagulation for CRRT, which is now used in approximately 50% of ICUs. This shift towards regional citrate anticoagulation for CRRT is occurring with little evidence of safety or longer term effectiveness. Renal replacement anticoagulant management (RRAM) is an observational comparative effectiveness study, utilising existing data sources to address the clinical and cost-effectiveness of the change to regional citrate anticoagulation for CRRT in UK ICUs. The study will use data from approximately 85,000 patients who were treated in adult, general ICUs participating in the case mix programme national clinical audit between 1 April 2009 and 31 March 2017. A survey of health service providers' anticoagulation practices will be combined with treatment and hospital outcome data from the case mix programme and linked with long-term outcomes from the Civil Registrations (deaths), Hospital Episodes Statistics for England, Patient Episodes Data for Wales, and the UK Renal Registry datasets. The primary clinical effectiveness outcome is all-cause mortality at 90-days. The study will incorporate an economic evaluation with micro-costing of both regional citrate anticoagulation and systemic heparin anticoagulation. Study registration: NCT03545750.

Implementation of ReSPECT in acute hospitals: A retrospective observational study.

AIMS: To evaluate, in UK acute hospitals, the early implementation of the Recommended Summary Plan for Emergency Care and Treatment (ReSPECT), which embeds cardiopulmonary resuscitation (CPR) recommendations within wider emergency treatment plans. To understand for whom and how the process was being used and the quality of form completion. METHODS: A retrospective observational study evaluating emergency care and treatment planning approaches used in acute UK hospitals (2015-2019), and in six English hospital trusts the extent of ReSPECT use, patient characteristics and completion quality in a sample 3000 patient case notes. RESULTS: The use of stand-alone Do Not Attempt Cardiopulmonary Resuscitation forms fell from 133/186 hospitals in 2015 to 64/186 in 2019 (a 38% absolute reduction). ReSPECT accounted for 52% (36/69) of changes. In the six sites, ReSPECT was used for approximately 20% of patients (range 6%-41%). They tended to be older, to have had an emergency medical admission, to have cognitive impairment and a lower predicted 10 year survival. Most (653/706 (92%)) included a 'not for attempted resuscitation' recommendation 551/706 (78%) had at least one other treatment recommendation. Capacity was not recorded on 13% (95/706) of forms; 11% (79/706) did not record patient/family involvement. CONCLUSIONS: ReSPECT use accounts for 52% of the change, observed between 2015 and 2019, from using standalone DNACPR forms to approaches embedding DNACPR decisions within in wider emergency care plans in NHS hospitals in the UK. Whilst recommendations include other emergencies most still tend to focus on recommendations relating to CPR. Completion of ReSPECT forms requires improvement. STUDY REGISTRATION: https://www.isrctn.com/ISRCTN11112933.

Protocol for a Randomized Multiple Center Trial of Conservative Versus Liberal Oxygenation Targets in Critically Ill Children (Oxy-PICU): Oxygen in Pediatric Intensive Care.

OBJECTIVES: Oxygen administration is a fundamental part of pediatric critical care, with supplemental oxygen offered to nearly every acutely unwell child. However, optimal targets for systemic oxygenation are unknown. Oxy-PICU aims to evaluate the clinical effectiveness and cost-effectiveness of a conservative peripheral oxygen saturation (Sp o2 ) target of 88-92% compared with a liberal target of more than 94%. DESIGN: Pragmatic, open, multiple-center, parallel group randomized control trial with integrated economic evaluation. SETTING: Fifteen PICUs across England, Wales, and Scotland. PATIENTS: Infants and children age more than 38 week-corrected gestational age to 16 years who are accepted to a participating PICU as an unplanned admission and receiving invasive mechanical ventilation with supplemental oxygen for abnormal gas exchange. INTERVENTION: Adjustment of ventilation and inspired oxygen settings to achieve an Sp o2 target of 88-92% during invasive mechanical ventilation. MEASUREMENTS AND MAIN RESULTS: Randomization is 1:1 to a liberal Sp o2 target of more than 94% or a conservative Sp o2 target of 88-92% (inclusive), using minimization with a random component. Minimization will be performed on: age, site, primary reason for admission, and severity of abnormality of gas exchange. Due to the emergency nature of the treatment, approaching patients for written informed consent will be deferred to after randomization. The primary clinical outcome is a composite of death and days of organ support at 30 days. Baseline demographics and clinical status will be recorded as well as daily measures of oxygenation and organ support, and discharge outcomes. This trial received Health Research Authority approval on December 23, 2019 (reference: 272768), including a favorable ethical opinion from the East of England-Cambridge South Research Ethics Committee (reference number: 19/EE/0362). Trial findings will be disseminated in national and international conferences and peer-reviewed journals.

Linkage of National Congenital Heart Disease Audit data to hospital, critical care and mortality national data sets to enable research focused on quality improvement.

OBJECTIVES: To link five national data sets (three registries, two administrative) and create longitudinal healthcare trajectories for patients with congenital heart disease (CHD), describing the quality and the summary statistics of the linked data set. DESIGN: Bespoke linkage of record-level patient identifiers across five national data sets. Generation of spells of care defined as periods of time-overlapping events across the data sets. SETTING: National Congenital Heart Disease Audit (NCHDA) procedures in public (National Health Service; NHS) hospitals in England and Wales, paediatric and adult intensive care data sets (Paediatric Intensive Care Audit Network; PICANet and the Case Mix Programme from the Intensive Care National Audit & Research Centre; ICNARC-CMP), administrative hospital episodes (hospital episode statistics; HES inpatient, outpatient, accident and emergency; A&E) and mortality registry data. PARTICIPANTS: Patients with any CHD procedure recorded in NCHDA between April 2000 and March 2017 from public hospitals. PRIMARY AND SECONDARY OUTCOME MEASURES: Primary: number of linked records, number of unique patients and number of generated spells of care. Secondary: quality and completeness of linkage. RESULTS: There were 143 862 records in NCHDA relating to 96 041 unique patients. We identified 65 797 linked PICANet patient admissions, 4664 linked ICNARC-CMP admissions and over 6 million linked HES episodes of care (1.1M inpatient, 4.7M outpatient). The linked data set had 4 908 153 spells of care after quality checks, with a median (IQR) of 3.4 (1.8-6.3) spells per patient-year. Where linkage was feasible (in terms of year and centre), 95.6% surgical procedure records were linked to a corresponding HES record, 93.9% paediatric (cardiac) surgery procedure records to a corresponding PICANet admission and 76.8% adult surgery procedure records to a corresponding ICNARC-CMP record. CONCLUSIONS: We successfully linked four national data sets to the core data set of all CHD procedures performed between 2000 and 2017. This will enable a much richer analysis of longitudinal patient journeys and outcomes. We hope that our detailed description of the linkage process will be useful to others looking to link national data sets to address important research priorities.

Heparin versus citrate anticoagulation for continuous renal replacement therapy in intensive care: the RRAM observational study.

BACKGROUND: In the UK, 10% of admissions to intensive care units receive continuous renal replacement therapy with regional citrate anticoagulation replacing systemic heparin anticoagulation over the last decade. Regional citrate anticoagulation is now used in > 50% of intensive care units, despite little evidence of safety or effectiveness. AIM: The aim of the Renal Replacement Anticoagulant Management study was to evaluate the clinical and health economic impacts of intensive care units moving from systemic heparin anticoagulation to regional citrate anticoagulation for continuous renal replacement therapy. DESIGN: This was an observational comparative effectiveness study. SETTING: The setting was NHS adult general intensive care units in England and Wales. PARTICIPANTS: Participants were adults receiving continuous renal replacement therapy in an intensive care unit participating in the Intensive Care National Audit & Research Centre Case Mix Programme national clinical audit between 1 April 2009 and 31 March 2017. INTERVENTIONS: Exposure - continuous renal replacement therapy in an intensive care unit after completion of transition to regional citrate anticoagulation. Comparator - continuous renal replacement therapy in an intensive care unit before starting transition to regional citrate anticoagulation or had not transitioned. OUTCOME MEASURES: Primary effectiveness - all-cause mortality at 90 days. Primary economic - incremental net monetary benefit at 1 year. Secondary outcomes - mortality at hospital discharge, 30 days and 1 year; days of renal, cardiovascular and advanced respiratory support in intensive care unit; length of stay in intensive care unit and hospital; bleeding and thromboembolic events; prevalence of end-stage renal disease at 1 year; and estimated lifetime incremental net monetary benefit. DATA SOURCES: Individual patient data from the Intensive Care National Audit & Research Centre Case Mix Programme were linked with the UK Renal Registry, Hospital Episode Statistics (for England), Patient Episodes Data for Wales and Civil Registrations (Deaths) data sets, and combined with identified periods of systemic heparin anticoagulation and regional citrate anticoagulation (survey of intensive care units). Staff time and consumables were obtained from micro-costing. Continuous renal replacement therapy system failures were estimated from the Post-Intensive Care Risk-adjusted Alerting and Monitoring data set. EuroQol-3 Dimensions, three-level version, health-related quality of life was obtained from the Intensive Care Outcomes Network study. RESULTS: Out of the 188 (94.9%) units that responded to the survey, 182 (96.8%) use continuous renal replacement therapy. After linkage, data were available from 69,001 patients across 181 intensive care units (60,416 during periods of systemic heparin anticoagulation use and 8585 during regional citrate anticoagulation use). The change to regional citrate anticoagulation was not associated with a step change in 90-day mortality (odds ratio 0.98, 95% confidence interval 0.89 to 1.08). Secondary outcomes showed step increases in days of renal support (difference in means 0.53 days, 95% confidence interval 0.28 to 0.79 days), advanced cardiovascular support (difference in means 0.23 days, 95% confidence interval 0.09 to 0.38 days) and advanced respiratory support (difference in means, 0.53 days, 95% CI 0.03 to 1.03 days) with a trend toward fewer bleeding episodes (odds ratio 0.90, 95% confidence interval 0.76 to 1.06) with transition to regional citrate anticoagulation. The micro-costing study indicated that regional citrate anticoagulation was more expensive and was associated with an estimated incremental net monetary loss (step change) of -£2376 (95% confidence interval -£3841 to -£911). The estimated likelihood of cost-effectiveness at 1 year was less than 0.1%. LIMITATIONS: Lack of patient-level treatment data means that the results represent average effects of changing to regional citrate anticoagulation in intensive care units. Administrative data are subject to variation in data quality over time, which may contribute to observed trends. CONCLUSIONS: The introduction of regional citrate anticoagulation has not improved outcomes for patients and is likely to have substantially increased costs. This study demonstrates the feasibility of evaluating effects of changes in practice using routinely collected data. FUTURE WORK: (1) Prioritise other changes in clinical practice for evaluation and (2) methodological research to understand potential implications of trends in data quality. TRIAL REGISTRATION: This trial is registered as ClinicalTrials.gov NCT03545750. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 26, No. 13. See the NIHR Journals Library website for further project information.

Acute kidney injury, which prevents kidneys from working properly, is common in critically ill patients being treated in an intensive care unit. Patients with acute kidney injury are treated with a machine that takes over kidney functions, a process called continuous renal replacement therapy. Traditionally, as part of continuous renal replacement therapy, heparin (an anticoagulant that stops the blood from clotting) is added to the blood as it enters the continuous renal replacement therapy machine. Recently, citrate anticoagulation (an alternative to heparin) has been increasingly used in intensive care units in the UK. However, the increased use of citrate is happening without evidence that this is better for patients and cost-effective for the NHS. We aimed to find out whether or not changing to citrate anticoagulation for continuous renal replacement therapy is more beneficial than heparin anticoagulation for patients with acute kidney injury treated in an intensive care unit. We also looked at whether or not changing to citrate is cost-effective for the NHS. We used routinely collected data from the Intensive Care National Audit & Research Centre Case Mix Programme national clinical audit to identify 69,001 patients who received continuous renal replacement therapy in an intensive care unit in England or Wales between 1 April 2009 and 31 March 2017. To get a more comprehensive view of the long-term effects of changing to citrate, we 'linked' data from the 69,001 patients together with other routinely collected data sets to get information on their hospital admissions, longer-term kidney problems and survival after leaving the intensive care unit. We combined this information with a survey of anticoagulant use in intensive care units in England and Wales to compare patients who received continuous renal replacement therapy with heparin and citrate. We found that the change to citrate was not associated with a significant change in the death rate at 90 days, but that it was more expensive for hospitals. Our findings suggest that the change to citrate-based anticoagulation may have been premature and should cause clinicians in intensive care units that are still using systemic heparin anticoagulation to pause before making this change.

Association between smoking, e-cigarette use and severe COVID-19: a cohort study.

BACKGROUND: Smoking is a risk factor for most respiratory infections, but it may protect against SARS-CoV-2 infection. The objective was to assess whether smoking and e-cigarette use were associated with severe COVID-19. METHODS: This cohort ran from 24 January 2020 until 30 April 2020 at the height of the first wave of the SARS-CoV-2 epidemic in England. It comprised 7 869 534 people representative of the population of England with smoking status, demographic factors and diseases recorded by general practitioners in the medical records, which were linked to hospital and death data. The outcomes were COVID-19-associated hospitalization, intensive care unit (ICU) admission and death. The associations between smoking and the outcomes were assessed with Cox proportional hazards models, with sequential adjustment for confounding variables and indirect causal factors (body mass index and smoking-related disease). RESULTS: Compared with never smokers, people currently smoking were at lower risk of COVID-19 hospitalization, adjusted hazard ratios (HRs) were 0.64 (95% confidence intervals 0.60 to 0.69) for <10 cigarettes/day, 0.49 (0.41 to 0.59) for 10-19 cigarettes/day, and 0.61 (0.49 to 0.74) for ≥20 cigarettes/day. For ICU admission, the corresponding HRs were 0.31 (0.24 to 0.40), 0.15 (0.06 to 0.36), and 0.35 (0.17 to 0.74) and death were: 0.79 (0.70 to 0.89), 0.66 (0.48 to 0.90), and 0.77 (0.54 to 1.09) respectively. Former smokers were at higher risk of severe COVID-19: HRs: 1.07 (1.03 to 1.11) for hospitalization, 1.17 (1.04 to 1.31) for ICU admission, and 1.17 (1.10 to 1.24) for death. All-cause mortality was higher for current smoking than never smoking, HR 1.42 (1.36 to 1.48). Among e-cigarette users, the adjusted HR for e-cigarette use and hospitalization with COVID-19 was 1.06 (0.88 to 1.28), for ICU admission was 1.04 (0.57 to 1.89, and for death was 1.12 (0.81 to 1.55). CONCLUSIONS: Current smoking was associated with a reduced risk of severe COVID-19 but the association with e-cigarette use was unclear. All-cause mortality remained higher despite this possible reduction in death from COVID-19 during an epidemic of SARS-CoV-2. Findings support investigating possible protective mechanisms of smoking for SARS-CoV-2 infection, including the ongoing trials of nicotine to treat COVID-19.

Inflammation and physical dysfunction: responses to moderate intensity exercise in chronic kidney disease.

BACKGROUND: People with chronic kidney disease (CKD) experience skeletal muscle wasting, reduced levels of physical function and performance, and chronic systemic inflammation. While it is known that a relationship exists between inflammation and muscle wasting, the association between inflammation and physical function or performance in CKD has not been well studied. Exercise has anti-inflammatory effects, but little is known regarding the effect of moderate intensity exercise. This study aimed to (i) compare systemic and intramuscular inflammation between CKD stage G3b-5 and non-CKD controls; (ii) establish whether a relationship exists between physical performance, exercise capacity and inflammation in CKD; (iii) determine changes in systemic and intramuscular inflammation following 12 weeks of exercise; and (iv) investigate whether improving inflammatory status via training contributes to improvements in physical performance and muscle mass. METHODS: This is a secondary analysis of previously collected data. CKD patients stages G3b-5 (n = 84, n = 43 males) and non-CKD controls (n = 26, n = 17 males) underwent tests of physical performance, exercise capacity, muscle strength and muscle size. In addition, a subgroup of CKD participants underwent 12 weeks of exercise training, randomized to aerobic (AE, n = 21) or combined (CE, n = 20) training. Plasma and intramuscular inflammation and myostatin were measured at rest and following exercise. RESULTS: Tumour necrosis factor-α was negatively associated with lower $^{^{^{.}}}{\rm V}$O2Peak (P = 0.01), Rectus femoris-cross sectional area (P = 0.002) and incremental shuttle walk test performance (P < 0.001). Interleukin-6 was negatively associated with sit-to-stand 60 performances (P = 0.006) and hand grip strength (P = 0.001). Unaccustomed exercise created an intramuscular inflammatory response that was attenuated following 12 weeks of training. Exercise training did not reduce systemic inflammation, but AE training did significantly reduce mature myostatin levels (P = 0.02). Changes in inflammation were not associated with changes in physical performance. CONCLUSIONS: Systemic inflammation may contribute to reduced physical function in CKD. Twelve weeks of exercise training was unable to reduce the level of chronic systemic inflammation in these patients, but did reduce plasma myostatin concentrations. Further research is required to further investigate this.