Comparison of medical admissions to intensive care units in the United States and United Kingdom

Underrepresentation and exclusion of patients with cardiovascular disease in intensive care randomized controlled trials

AIMS

The complexity of the contemporary cardiac intensive care unit has increased due to a growing prevalence of multisystem, non-cardiac illnesses. Despite this increase, patients with cardiovascular disease (CVD) are often under-represented in intensive care randomized controlled trials (RCT). We sought to quantify the representation of patients with CVD comorbidities in intensive care RCTs.

METHODS AND RESULTS

We searched MEDLINE for trials published from 2007 to 2019 with the five highest journal impact factors in the disciplines of critical care medicine, general internal medicine, and cardiovascular disease. Prospective RCTs in the adult (age ≥18 years), intensive care setting with ≥50 individuals were included. Study characteristics, proportion of patients with CVD and cardiovascular exclusion criteria were extracted independently by two reviewers. We used multivariable logistic regression analysis to identify independent predictors of cardiovascular exclusion and representation. A total of 412 eligible RCTs were identified for analysis, 132 (32.0%) of which included specific CVD-related exclusion criteria with a history of heart failure (29.5%) and of ischaemic heart disease (26.5%) being the most common exclusions. Exclusions were more likely in multicentre trials and varied substantially across study intervention categories. Representation of CVD, reflected by the reporting of any CVD history, was noted in 150 (36.4%) RCTs. Of those reporting, the prevalence of any CVD, ischaemic heart disease and heart failure were 15.7%, 13.2%, and 10.2%, respectively.

CONCLUSION

Those with comorbid CVD are both frequently excluded and underrepresented in intensive care RCTs, limiting the application of RCTs to this physiologically complex patient population.

Knowledge, attitudes and practices of multiprofessional clinicians towards assisted dying in ICU: A scoping review

BACKGROUND

Care of the dying is at the forefront in intensive care unit (ICU); however there is persistent debate surrounding clinicians' interventions to aid the dying process and make this more bearable and compassionate for patients. Since the expansion of assisted dying internationally, it is unclear how common this occurs within critical care. This work aims to evaluate the knowledge, attitudes and international practices of ICU clinicians about assisted dying.

METHODS

Systematic literature search of PubMed, Embase and CINAHL including articles discussing the knowledge or attitudes towards and/or practices of assisted dying in ICU. The preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review guidelines were followed. Records were included from 2002 as the year when assisted dying was first legalised in Belgium and by healthcare professionals. A qualitative data synthesis approach was used.

RESULTS

17 studies were eligible and included in the qualitative analysis. Knowledge of assisted dying was rarely assessed directly in the data, though self-reported knowledge was low apart from in one Canadian survey of ICU physicians. Abilities to define modalities of assisted dying were low across all studies where it was measured. Attitudes were highly variable, ranging from 23.6% to 76.5% in support of assisted dying, though clinicians' answers were inconsistent within and between studies. Actual practices of assisted dying in ICU were rarely measured or discussed, despite evidence of assisted dying in Canada and The Netherlands. Outside of legal pathways, there is also evidence of covert interventions either via non-framework approaches where it is otherwise legal or in countries where there is no supportive legislation.

CONCLUSION

ICU clinicians have heterogeneous knowledge and attitudes towards assisted dying, and overall familiarity remains low. The relevance of assisted dying to the ICU setting remains controversial, and its incidence is unclear.

IMPLICATIONS FOR CLINICAL PRACTICE

Evaluating the attitudes and experiences of ICU clinicians about assisted dying is important to gain insight about clinical practices. This holistic viewpoint is key to develop management strategies focused on humanisation of care for patients and families while understanding how to support multidisciplinary clinicians in critical care so they can provide safe and respectful interventions. The identification of its incidence in legal and illegal frameworks and knowledge gaps is key when developing further research and planning tailored interventions.

Heterogeneity of treatment effect: the case for individualising oxygen therapy in critically ill patients

Oxygen therapy is ubiquitous in critical illness but oxygenation targets to guide therapy remain controversial despite several large randomised controlled trials (RCTs). Findings from RCTs evaluating different approaches to oxygen therapy in critical illness present a confused picture for several reasons. Differences in both oxygen target measures (e.g. oxygen saturation or partial pressure) and the numerical thresholds used to define lower and higher targets complicate comparisons between trials. The duration of and adherence to oxygenation targets is also variable with consequent substantial variation in both the dose and the dose separation. Finally, heterogeneity of treatment effects (HTE) may also be a significant factor. HTE is defined as non-random variation in the benefit or harm of a treatment, in which the variation is associated with or attributable to patient characteristics. This narrative review aims to make the case that such heterogeneity is likely in relation to oxygen therapy for critically ill patients and that this has significant implications for the design and interpretation of trials of oxygen therapy in this context. HTE for oxygen therapy amongst critically ill patients may explain the contrasting results from different clinical trials of oxygen therapy. Individualised oxygen therapy may overcome this challenge, and future studies should incorporate ways to evaluate this approach.

A Clinician's Guide to Understanding Bias in Critical Clinical Prediction Models

This narrative review focuses on the role of clinical prediction models in supporting informed decision-making in critical care, emphasizing their 2 forms: traditional scores and artificial intelligence (AI)-based models. Acknowledging the potential for both types to embed biases, the authors underscore the importance of critical appraisal to increase our trust in models. The authors outline recommendations and critical care examples to manage risk of bias in AI models. The authors advocate for enhanced interdisciplinary training for clinicians, who are encouraged to explore various resources (books, journals, news Web sites, and social media) and events (Datathons) to deepen their understanding of risk of bias.

Characteristics, Management, and Outcomes of Acute Life-Threatening Asthma in Adult Intensive Care

BACKGROUND

There is limited evidence regarding the management of acute life-threatening asthma in intensive care units (ICUs), and few guidelines have details on this. We aimed to describe the characteristics, management, and outcomes of adults with life-threatening asthma requiring ICU admission.

METHODS

In this single-centre retrospective observational study, we included consecutive adults with acute asthma requiring ICU admission between 1 January 2016 and 31 December 2023. Our primary outcome was requirement for invasive mechanical ventilation (IMV).

RESULTS

We included 100 patients (median age 42.5 years, 67% female). The median pH, PaCO2, and white cell count (WCC) on ICU admission were 7.37, 39 mmHg, and 13.6 × 109/L. There were 30 patients (30%) who required IMV, and the best predictors of IMV requirement were pH (AUC 0.772) and PaCO2 (AUC 0.809). In univariate analysis, IMV requirement was associated with both increasing WCC (OR 1.14) and proven bacterial infection (OR 8.50). A variety of respiratory support strategies were utilised, with 38 patients (38%) receiving only non-invasive respiratory support.

CONCLUSIONS

Our data highlight key characteristics which may be risk factors for acute asthma requiring ICU admission and suggest that pH, PaCO2, and WCC are prognostic markers for disease severity. Our overall outcomes were good, with an IMV requirement of 30% and a 28-day mortality of 1%.

Beyond Unplanned ICU Transfers: Linking a Revised Definition of Deterioration to Patient Outcomes

OBJECTIVES

To develop an electronic descriptor of clinical deterioration for hospitalized patients that predicts short-term mortality and identifies patient deterioration earlier than current standard definitions.

DESIGN

A retrospective study using exploratory record review, quantitative analysis, and regression analyses.

SETTING

Twelve-hospital community-academic health system.

PATIENTS

All adult patients with an acute hospital encounter between January 1, 2018, and December 31, 2022.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND MAIN RESULTS

Clinical trigger events were selected and used to create a revised electronic definition of deterioration, encompassing signals of respiratory failure, bleeding, and hypotension occurring in proximity to ICU transfer. Patients meeting the revised definition were 12.5 times more likely to die within 7 days (adjusted odds ratio 12.5; 95% CI, 8.9-17.4) and had a 95.3% longer length of stay (95% CI, 88.6-102.3%) compared with those who were transferred to the ICU or died regardless of meeting the revised definition. Among the 1812 patients who met the revised definition of deterioration before ICU transfer (52.4%), the median detection time was 157.0 min earlier (interquartile range 64.0-363.5 min).

CONCLUSIONS

The revised definition of deterioration establishes an electronic descriptor of clinical deterioration that is strongly associated with short-term mortality and length of stay and identifies deterioration over 2.5 hours earlier than ICU transfer. Incorporating the revised definition of deterioration into the training and validation of early warning system algorithms may enhance their timeliness and clinical accuracy.

Utilization and Outcomes in U.S. ICU Hospitalizations

OBJECTIVES

Despite its importance, detailed national estimates of ICU utilization and outcomes remain lacking. We aimed to characterize trends in ICU utilization and outcomes over a recent 12-year period in the United States.

DESIGN/SETTING

In this longitudinal study, we examined hospitalizations involving ICU care ("ICU hospitalizations") alongside hospitalizations not involving ICU care ("non-ICU hospitalizations") among traditional Medicare beneficiaries using 100% Medicare part A claims data and commercial claims data for the under 65 adult population from 2008 to 2019.

PATIENTS/INTERVENTIONS

There were 18,313,637 ICU hospitalizations and 78,501,532 non-ICU hospitalizations in Medicare, and 1,989,222 ICU hospitalizations and 16,732,960 non-ICU hospitalizations in the commercially insured population.

MEASUREMENTS AND MAIN RESULTS

From 2008 to 2019, about 20% of Medicare hospitalizations and 10% of commercial hospitalizations involved ICU care. Among these ICU hospitalizations, length of stay and ICU length of stay decreased on average. Mortality and hospital readmissions on average also decreased, and they decreased more among ICU hospitalizations than among non-ICU hospitalizations, for both Medicare and commercially insured patients. Both Medicare and commercial populations experienced a growth in shorter ICU hospitalizations (between 2 and 7 d in length), which were characterized by shorter ICU stays and lower mortality. Among these short hospitalizations in the Medicare population, for common clinical diagnoses cared for in both ICU and non-ICU settings, patients were increasingly triaged into an ICU during the study period, despite being younger and having shorter hospital stays.

CONCLUSIONS

ICUs are used in a sizeable share of hospitalizations. From 2008 to 2019, ICU length of stay and mortality have declined, while short ICU hospitalizations have increased. In particular, for clinical conditions often managed both within and outside of an ICU, shorter ICU hospitalizations involving younger patients have increased. Our findings motivate opportunities to better understand ICU utilization and to improve the value of ICU care for patients and payers.

One-year transplant-free survival following hospital discharge after ICU admission for ACLF in the Netherlands

BACKGROUND & AIMS

Patients with acute decompensation of cirrhosis or acute-on-chronic liver failure (ACLF) often require intensive care unit (ICU) admission for organ support. Existing research, mostly from specialized liver transplant centers, largely addresses short-term outcomes. Our aim was to evaluate in-hospital mortality and 1-year transplant-free survival after hospital discharge in the Netherlands.

METHODS

We conducted a nationwide observational cohort study, including patients with a history of cirrhosis or first complications of cirrhotic portal hypertension admitted to ICUs in the Netherlands between 2012 and 2020. The influence of ACLF grade at ICU admission on 1-year transplant-free survival after hospital discharge among hospital survivors was evaluated using unadjusted Kaplan-Meier survival curves and an adjusted Cox proportional hazard model.

RESULTS

Out of the 3,035 patients, 1,819 (59.9%) had ACLF-3. 1,420 patients (46.8%) survived hospitalization after ICU admission. The overall probability of 1-year transplant-free survival after hospital discharge was 0.61 (95% CI 0.59-0.64). This rate varied with ACLF grade at ICU admission, being highest in patients without ACLF (0.71; 95% CI 0.66-0.76) and lowest in those with ACLF-3 (0.53 [95% CI 0.49-0.58]) (log-rank p <0.0001). However, after adjusting for age, malignancy status and MELD score, ACLF grade at ICU admission was not associated with an increased risk of liver transplantation or death within 1 year after hospital discharge.

CONCLUSION

In this nationwide cohort study, ACLF grade at ICU admission did not independently affect 1-year transplant-free survival after hospital discharge. Instead, age, presence of malignancy and the severity of liver disease played a more prominent role in influencing transplant-free survival after hospital discharge.

IMPACT AND IMPLICATIONS

Patients with acute-on-chronic liver failure often require intensive care unit (ICU) admission for organ support. In these patients, short-term mortality is high, but long-term outcomes of survivors remain unknown. Using a large nationwide cohort of ICU patients, we discovered that the severity of acute-on-chronic liver failure at ICU admission does not influence 1-year transplant-free survival after hospital discharge. Instead, age, malignancy status and overall severity of liver disease are more critical factors in determining their long-term survival.

Frailty assessment in critically ill older adults: a narrative review

Frailty, a condition that was first defined 20 years ago, is now assessed via multiple different tools. The Frailty Phenotype was initially used to identify a population of "pre-frail" and "frail" older adults, so as to prevent falls, loss of mobility, and hospitalizations. A different definition of frailty, via the Clinical Frailty Scale, is now actively used in critical care situations to evaluate over 65 year-old patients, whether it be for Intensive Care Unit (ICU) admissions, limitation of life-sustaining treatments or prognostication. Confusion remains when mentioning "frailty" in older adults, as to which tools are used, and what the impact or the bias of using these tools might be. In addition, it is essential to clarify which tools are appropriate in medical emergencies. In this review, we clarify various concepts and differences between frailty, functional autonomy and comorbidities; then focus on the current use of frailty scales in critically ill older adults. Finally, we discuss the benefits and risks of using standardized scales to describe patients, and suggest ways to maintain a complex, three-dimensional, patient evaluation, despite time constraints. Frailty in the ICU is common, involving around 40% of patients over 75. The most commonly used scale is the Clinical Frailty Scale (CFS), a rapid substitute for Comprehensive Geriatric Assessment (CGA). Significant associations exist between the CFS-scale and both short and long-term mortality, as well as long-term outcomes, such as loss of functional ability and being discharged home. The CFS became a mainstream tool newly used for triage during the Covid-19 pandemic, in response to the pressure on healthcare systems. It was found to be significantly associated with in-hospital mortality. The improper use of scales may lead to hastened decision-making, especially when there are strains on healthcare resources or time-constraints. Being aware of theses biases is essential to facilitate older adults' access to equitable decision-making regarding critical care. The aim is to help counteract assessments which may be abridged by time and organisational constraints.

Validation of the emergency surgery score (ESS) in a UK patient population and comparison with NELA scoring: a retrospective multicentre cohort study

INTRODUCTION

Accurate risk scoring in emergency general surgery (EGS) is vital for consent and resource allocation. The emergency surgery score (ESS) has been validated as a reliable preoperative predictor of postoperative outcomes in EGS but has been studied only in the US population. Our primary aim was to perform an external validation study of the ESS in a UK population. Our secondary aim was to compare the accuracy of ESS and National Emergency Laparotomy Audit (NELA) scores.

METHODS

We conducted an observational cohort study of adult patients undergoing emergency laparotomy over three years in two UK centres. ESS was calculated retrospectively. NELA scores and all other variables were obtained from the prospectively collected Emergency Laparotomy and Laparoscopic Scottish Audit (ELLSA) database. The primary and secondary outcomes were 30-day mortality and postoperative intensive care unit (ICU) admission, respectively.

RESULTS

A total of 609 patients were included. Median age was 65 years, 52.7% were female, the overall mortality was 9.9% and 23.8% were admitted to ICU. Both ESS and NELA were equally accurate in predicting 30-day mortality (c-statistic=0.78 (95% confidence interval (CI), 0.71-0.85) for ESS and c-statistic=0.83 (95% CI, 0.77-0.88) for NELA, p=0.196) and predicting postoperative ICU admission (c-statistic=0.76 (95% CI, 0.71-0.81) for ESS and 0.80 (95% CI, 0.76-0.85) for NELA, p=0.092).

CONCLUSIONS

In the UK population, ESS and NELA both predict 30-day mortality and ICU admission with no statistically significant difference but with higher c-statistics for NELA score. Both scores have certain advantages, with ESS being validated for a wider range of outcomes.

Protocol and Statistical Analysis Plan for the Mode of Ventilation During Critical Illness (MODE) Trial

BACKGROUND

For every critically ill adult receiving invasive mechanical ventilation, clinicians must select a mode of ventilation. The mode of ventilation determines whether the ventilator directly controls the tidal volume or the inspiratory pressure. Newer hybrid modes allow clinicians to set a target tidal volume; the ventilator controls and adjusts the inspiratory pressure. A strategy of low tidal volumes and low plateau pressure improves outcomes, but the optimal mode to achieve these targets is not known.

RESEARCH QUESTION

Can a cluster-randomized trial design be used to assess whether the mode of mandatory ventilation affects the number of days alive and free of invasive mechanical ventilation among critically ill adults?

STUDY DESIGN AND METHODS

The Mode of Ventilation During Critical Illness (MODE) trial is a cluster-randomized, multiple-crossover pilot trial being conducted in the medical ICU at an academic center. The MODE trial compares the use of volume control, pressure control, and adaptive pressure control. The study ICU is assigned to a single-ventilator mode (volume control vs pressure control vs adaptive pressure control) for continuous mandatory ventilation during each 1-month study block. The assigned mode switches every month in a randomly generated sequence. The primary outcome is ventilator-free days to study day 28, defined as the number of days alive and free of invasive mechanical ventilation from the final receipt of mechanical ventilation to 28 days after enrollment. Enrollment began November 1, 2022, and will end on July 31, 2023.

RESULTS

This manuscript describes the protocol and statistical analysis plan for the MODE trial of ventilator modes comparing volume control, pressure control, and adaptive pressure control.

INTERPRETATION

Prespecifying the full statistical analysis plan prior to completion of enrollment increases rigor, reproducibility, and transparency of the trial results.

CLINICAL TRIAL REGISTRATION

The trial was registered with clinicaltrials.gov on October 3, 2022, before initiation of patient enrollment on November 1, 2022 (ClinicalTrials.gov identifier: NCT05563779).

Temporal Trends in Mortality of Critically Ill Patients with Sepsis in the United Kingdom, 1988-2019

Rationale: Sepsis is a frequent cause of ICU admission and mortality. Objectives: To evaluate temporal trends in the presentation and outcomes of patients admitted to the ICU with sepsis and to assess the contribution of changing case mix to outcomes. Methods: We conducted a retrospective cohort study of patients admitted to 261 ICUs in the United Kingdom during 1988-1990 and 1996-2019 with nonsurgical sepsis. Measurements and Main Results: A total of 426,812 patients met study inclusion criteria. The patients had a median (interquartile range) age of 66 (53-75) years, and 55.6% were male. The most common sites of infection were respiratory (60.9%), genitourinary (11.5%), and gastrointestinal (10.3%). Compared with patients in 1988-1990, patients in 2017-2019 were older (median age, 66 vs. 63 yr), were less acutely ill (median Acute Physiology and Chronic Health Evaluation II acute physiology score, 14 vs. 20), and more often had genitourinary sepsis (13.4% vs. 2.0%). Hospital mortality decreased from 54.6% (95% confidence interval [CI], 51.0-58.1%) in 1988-1990 to 32.4% (95% CI, 32.1-32.7%) in 2017-2019, with an adjusted odds ratio of 0.64 (95% CI, 0.54-0.75). The adjusted absolute hospital mortality reduction from 1988-1990 to 2017-2019 was 8.8% (95% CI, 5.6-12.1). Thus, of the observed 22.2-percentage point reduction in hospital mortality, 13.4 percentage points (60% of total reduction) were explained by case mix changes, whereas 8.8 percentage points (40% of total reduction) were not explained by measured factors and may be a result of improvements in ICU management. Conclusions: Over a 30-year period, mortality for ICU admissions with sepsis decreased substantially. Although changes in case mix accounted for the majority of observed mortality reduction, there was an 8.8-percentage point reduction in mortality not explained by case mix.

Critical Bias in Critical Care Devices

Critical care data contain information about the most physiologically fragile patients in the hospital, who require a significant level of monitoring. However, medical devices used for patient monitoring suffer from measurement biases that have been largely underreported. This article explores sources of bias in commonly used clinical devices, including pulse oximeters, thermometers, and sphygmomanometers. Further, it provides a framework for mitigating these biases and key principles to achieve more equitable health care delivery.

Use of Mechanical Ventilation Across 3 Countries

Importance

The ability to provide invasive mechanical ventilation (IMV) is a mainstay of modern intensive care; however, whether rates of IMV vary among countries is unclear.

Objective

To estimate the per capita rates of IMV in adults across 3 high-income countries with large variation in per capita intensive care unit (ICU) bed availability.

Design, Setting, and Participants

This cohort study examined 2018 data of patients aged 20 years or older who received IMV in England, Canada, and the US.

Exposure

The country in which IMV was received.

Main Outcomes and Measures

The main outcome was the age-standardized rate of IMV and ICU admissions in each country. Rates were stratified by age, specific diagnoses (acute myocardial infarction, pulmonary embolus, upper gastrointestinal bleed), and comorbidities (dementia, dialysis dependence). Data analyses were conducted between January 1, 2021, and December 1, 2022.

Results

The study included 59 873 hospital admissions with IMV in England (median [IQR] patient age, 61 [47-72] years; 59% men, 41% women), 70 250 in Canada (median [IQR] patient age, 65 [54-74] years; 64% men, 36% women), and 1 614 768 in the US (median [IQR] patient age, 65 [54-74] years; 57% men, 43% women). The age-standardized rate per 100 000 population of IMV was the lowest in England (131; 95% CI, 130-132) compared with Canada (290; 95% CI, 288-292) and the US (614; 95% CI, 614-615). Stratified by age, per capita rates of IMV were more similar across countries among younger patients and diverged markedly in older patients. Among patients aged 80 years or older, the crude rate of IMV per 100 000 population was highest in the US (1788; 95% CI, 1781-1796) compared with Canada (694; 95% CI, 679-709) and England (209; 95% CI, 203-214). Concerning measured comorbidities, 6.3% of admitted patients who received IMV in the US had a diagnosis of dementia (vs 1.4% in England and 1.3% in Canada). Similarly, 5.6% of admitted patients in the US were dependent on dialysis prior to receiving IMV (vs 1.3% in England and 0.3% in Canada).

Conclusions and Relevance

This cohort study found that patients in the US received IMV at a rate 4 times higher than in England and twice that in Canada in 2018. The greatest divergence was in the use of IMV among older adults, and patient characteristics among those who received IMV varied markedly. The differences in overall use of IMV among these countries highlight the need to better understand patient-, clinician-, and systems-level choices associated with the varied use of a limited and expensive resource.

Protocol and statistical analysis plan for the Mode of Ventilation During Critical IllnEss (MODE) trial

Introduction

For every critically ill adult receiving invasive mechanical ventilation, clinicians must select a mode of ventilation. The mode of ventilation determines whether the ventilator directly controls the tidal volume or the inspiratory pressure. Newer hybrid modes allow clinicians to set a target tidal volume, for which the ventilator controls and adjusts the inspiratory pressure. A strategy of low tidal volumes and low plateau pressure improves outcomes, but the optimal mode to achieve these targets is not known.

Methods and analysis

The Mode of Ventilation During Critical Illness (MODE) trial is a cluster-randomized, multiple-crossover pilot trial being conducted in the medical intensive care unit (ICU) at an academic center. The MODE trial compares the use of volume control, pressure control, and adaptive pressure control. The study ICU is assigned to a single ventilator mode (volume control versus pressure control versus adaptive pressure control) for continuous mandatory ventilation during each 1-month study block. The assigned mode switches every month in a randomly generated sequence. The primary outcome is ventilator-free days (VFDs) to study day 28, defined as the number of days alive and free of invasive mechanical ventilation from the final receipt of mechanical ventilation to 28 days after enrollment. Enrollment began November 1, 2022 and will end on July 31, 2023.

Ethics and dissemination

The trial was approved by the Vanderbilt University Medical Center institutional review board (IRB# 220446). Results of this study will be submitted to a peer-reviewed journal and presented at scientific conferences.

Trial registration number

The trial was registered with clinicaltrials.gov on October 3, 2022, prior to initiation of patient enrollment on November 1, 2022 (ClinicalTrials.gov identifier: NCT05563779).

Efficacy and safety of intravenous leukotriene receptor antagonists in acute asthma

The incidence of bronchial asthma has increased substantially since recent decades in both children and adults. Moreover, the number of patients presenting with asthma exacerbation to the emergency department has also increased in several countries. Leukotrienes are inflammatory mediators that play an important role in bronchial asthma exacerbation. Leukotriene receptor antagonists reduce asthma exacerbation in chronic asthma; moreover, the current guidelines for asthma management recommend the use of oral leukotriene receptor antagonists for asthma control and reduce further exacerbation. However, data on the use of intravenous leukotriene receptor antagonists during acute asthma exacerbation are scarce. Nevertheless, currently available data revealed a trend of significant improvement of acute asthma and rapid reversal of airflow obstruction when administered during an acute asthma attack. This review aims to summarize currently available data on the use of intravenous leukotriene receptor antagonists in adult patients with acute asthma exacerbation.

Among-Hospital Variation in Intensive Care Unit Admission Practices and Associated Outcomes for Patients with Acute Respiratory Failure

Rationale: We have previously shown that hospital strain is associated with intensive care unit (ICU) admission and that ICU admission, compared with ward admission, may benefit certain patients with acute respiratory failure (ARF). Objectives: To understand how strain-process-outcomes relationships in patients with ARF may vary among hospitals and what hospital practice differences may account for such variation. Methods: We examined high-acuity patients with ARF who did not require mechanical ventilation or vasopressors in the emergency department (ED) and were admitted to 27 U.S. hospitals from 2013 to 2018. Stratifying by hospital, we compared hospital strain-ICU admission relationships and hospital length of stay (LOS) and mortality among patients initially admitted to the ICU versus the ward using hospital strain as a previously validated instrumental variable. We also surveyed hospital practices and, in exploratory analyses, evaluated their associations with the above processes and outcomes. Results: There was significant among-hospital variation in ICU admission rates, in hospital strain-ICU admission relationships, and in the association of ICU admission with hospital LOS and hospital mortality. Overall, ED patients with ARF (n = 45,339) experienced a 0.82-day shorter median hospital LOS if admitted initially to the ICU compared with the ward, but among the 27 hospitals (n = 224-3,324), this effect varied from 5.85 days shorter (95% confidence interval [CI], -8.84 to -2.86; P < 0.001) to 4.38 days longer (95% CI, 1.86-6.90; P = 0.001). Corresponding ranges for in-hospital mortality with ICU compared with ward admission revealed odds ratios from 0.08 (95% CI, 0.01-0.56; P < 0.007) to 8.89 (95% CI, 1.60-79.85; P = 0.016) among patients with ARF (pooled odds ratio, 0.75). In exploratory analyses, only a small number of measured hospital practices-the presence of a sepsis ED disposition guideline and maximum ED patient capacity-were potentially associated with hospital strain-ICU admission relationships. Conclusions: Hospitals vary considerably in ICU admission rates, the sensitivity of those rates to hospital capacity strain, and the benefits of ICU admission for patients with ARF not requiring life support therapies in the ED. Future work is needed to more fully identify hospital-level factors contributing to these relationships.

Oxygen-Saturation Targets for Critically Ill Adults Receiving Mechanical Ventilation

BACKGROUND

Invasive mechanical ventilation in critically ill adults involves adjusting the fraction of inspired oxygen to maintain arterial oxygen saturation. The oxygen-saturation target that will optimize clinical outcomes in this patient population remains unknown.

METHODS

In a pragmatic, cluster-randomized, cluster-crossover trial conducted in the emergency department and medical intensive care unit at an academic center, we assigned adults who were receiving mechanical ventilation to a lower target for oxygen saturation as measured by pulse oximetry (Spo₂) (90%; goal range, 88 to 92%), an intermediate target (94%; goal range, 92 to 96%), or a higher target (98%; goal range, 96 to 100%). The primary outcome was the number of days alive and free of mechanical ventilation (ventilator-free days) through day 28. The secondary outcome was death by day 28, with data censored at hospital discharge.

RESULTS

A total of 2541 patients were included in the primary analysis. The median number of ventilator-free days was 20 (interquartile range, 0 to 25) in the lower-target group, 21 (interquartile range, 0 to 25) in the intermediate-target group, and 21 (interquartile range, 0 to 26) in the higher-target group (P = 0.81). In-hospital death by day 28 occurred in 281 of the 808 patients (34.8%) in the lower-target group, 292 of the 859 patients (34.0%) in the intermediate-target group, and 290 of the 874 patients (33.2%) in the higher-target group. The incidences of cardiac arrest, arrhythmia, myocardial infarction, stroke, and pneumothorax were similar in the three groups.

CONCLUSIONS

Among critically ill adults receiving invasive mechanical ventilation, the number of ventilator-free days did not differ among groups in which a lower, intermediate, or higher Spo₂ target was used. (Supported by the National Heart, Lung, and Blood Institute and others; PILOT ClinicalTrials.gov number, NCT03537937.).

Geographical and Temporal Analysis of Tweets Related to COVID-19 and Cardiovascular Disease in the US

The COVID-19 pandemic has resulted in more than 600 million confirmed cases worldwide since December 2021. Cardiovascular disease (CVD) is both a risk factor for COVID-19 mortality and a complication that many COVID-19 patients develop. This study uses Twitter data to identify the spatiotemporal patterns and correlation of related tweets with daily COVID-19 cases and deaths at the national, regional, and state levels. We collected tweets mentioning both COVID-19 and CVD-related words from February to July 2020 (Eastern Time) and geocoded the tweets to the state level using GIScience techniques. We further proposed and validated that the Twitter user registration state can be a feasible proxy of geotags. We applied geographical and temporal analysis to investigate where and when people talked about COVID-19 and CVD. Our results indicated that the trend of COVID-19 and CVD-related tweets is correlated to the trend of COVID-19, especially the daily deaths. These social media messages revealed widespread recognition of CVD's important role in the COVID-19 pandemic, even before the medical community started to develop consensus and theory supports about CVD aspects of COVID-19. The second wave of the pandemic caused another rise in the related tweets but not as much as the first one, as tweet frequency increased from February to April, decreased till June, and bounced back in July. At the regional level, four regions (Northeast, Midwest, North, and West) had the same trend of related tweets compared to the country as a whole. However, only the Northeast region had a high correlation (0.8-0.9) between the tweet count, new cases, and new deaths. For the second wave of confirmed new cases, the major contributing regions, South and West, did not ripple as many related tweets as the first wave. Our understanding is that the early news attracted more attention and discussion all over the U.S. in the first wave, even though some regions were not impacted as much as the Northeast at that time. The study can be expanded to more geographic and temporal scales, and with more physical and socioeconomic variables, with better data acquisition in the future.

External validation of the ProVent score for prognostication of 1-year mortality of critically ill patients with prolonged mechanical ventilation: a single-centre, retrospective observational study in Austria

OBJECTIVES

In critically ill patients requiring mechanical ventilation for at least 21 days, 1-year mortality can be estimated using the ProVent score, calculated from four variables (age, platelet count, vasopressor use and renal replacement therapy). We aimed to externally validate discrimination and calibration of the ProVent score and, if necessary, to update its underlying regression model.

DESIGN

Retrospective, observational, single-centre study.

SETTING

11 intensive care units at one tertiary academic hospital.

PATIENTS

780 critically ill adult patients receiving invasive mechanical ventilation for at least 21 days.

PRIMARY OUTCOME MEASURE

1-year mortality after intensive care unit discharge.

RESULTS

380 patients (49%) had died after 1 year. One-year mortality for ProVent scores from 0 to 5 were: 15%, 27%, 57%, 66%, 72% and 76%. Area under the receiver operating characteristic curve of the ProVent probability model was 0.76 (95% CI 0.72 to 0.79), calibration intercept was -0.43 (95% CI -0.59 to -0.27) and calibration slope was 0.76 (95% CI 0.62 to 0.89). Model recalibration and extension by inclusion of three additional predictors (total bilirubin concentration, enteral nutrition and surgical status) improved model discrimination and calibration. Decision curve analysis demonstrated that the original ProVent model had negative net benefit, which was avoided with the extended ProVent model.

CONCLUSIONS

The ProVent probability model had adequate discrimination but was miscalibrated in our patient cohort and, as such, could potentially be harmful. Use of the extended ProVent score developed by us could possibly alleviate this concern.

Prophylactic acid suppressants in patients with primary neurologic injury: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

Neurocritical care patients are at risk of stress-induced gastrointestinal ulceration. We performed a systematic review and meta-analysis of stress ulcer prophylaxis (SUP) in critically ill adults admitted with a primary neurologic injury.

MATERIALS AND METHODS

We included randomized controlled trials (RCTs) comparing SUP with histamine-2-receptor antagonists (H2RAs) or proton pump inhibitors (PPIs) to placebo/no prophylaxis, as well as to each other. The primary outcome was in-ICU gastrointestinal bleeding (GIB). Predefined secondary outcomes were all-cause 30-day mortality, ICU length of stay (LOS), nosocomial pneumonia, and other complications.

RESULTS

We identified 14 relevant trials enrolling 1036 neurocritical care patients; 11 trials enrolling 930 patients were included in the meta-analysis. H2RAs resulted in a lower incidence of GIB as compared to placebo or no prophylaxis (Risk ratio [RR] 0.42, 95% CI 0.30-0.58; p < 0.001); PPIs with a lower risk of GIB compared to placebo/no prophylaxis (RR 0.37, 95% CI 0.23-0.59; p < 0.001). No significant difference was observed in GIB comparing PPIs with H2RAs (RR 0.53, 95% CI 0.26-1.06; p = 0.07; I² = 0%).

CONCLUSIONS

In neurocritical care patients, the overall high or unclear risk of bias of individual trials, the low event rates, and modest sample sizes preclude strong clinical inferences about the utility of SUP.

A pragmatic method to compare international critical care beds: Implications to pandemic preparedness and non-pandemic planning

BACKGROUND

The current method for assessing critical care (CCU) bed numbers between countries is unreliable.

METHODS

A pragmatic method is presented using a logarithmic relationship between CCU beds per 1000 deaths and deaths per 1000 population, both of which are readily available. The method relies on the importance of the nearness to death effect, and on the effect of population size.

RESULTS

The method was tested using CCU bed numbers from 65 countries. A series of logarithmic relationships can be seen. High versus low countries can be distinguished by adjusting all countries to a common crude mortality rate. Hence at 9.5 deaths per 1000 population 'high' CCU bed countries average of around 30 CCU beds per 1000 deaths, while 'very low' countries only average 3 CCU beds per 1000 deaths. The United Kingdom falls among countries with low critical care provision with an average of 8 CCU beds per 1000 deaths, and during the COVID-19 epidemic UK industry intervened to rapidly manufacture various types of ventilators to avoid a catastrophe. CCU bed numbers in India are around 8.1 per 1000 deaths, which places it in the low category. However, such beds are inequitably distributed with the poorest states all in the 'very low' category. In India only around 50% of CCU beds have a ventilator.

CONCLUSION

A feasible region is defined for the optimum number of CCU beds.

Intensive care unit capacity and mortality in older adults: a three nations retrospective observational cohort study

Background

Intensive care unit (ICU) admissions among older adults are expected to increase, while the benefit remains uncertain. The availability of ICU beds varies between hospitals and between countries and is an important factor in the decision to admit older adults in the ICU. We aimed to assess if a non-restrictive approach to ICU older adults admission is associated with a corresponding change in survival.

Methods

Retrospective cohort study that included patients ≥ 80 years who were admitted to each of the three participating hospitals in Australia, Israel, and the United States (USA), between the years 2006–2015, each with distinct ICU capacities and admission criteria. The primary outcomes were in-hospital mortality and all-cause mortality at 6, 12, 18, and 24 months following index hospitalization.

Results

The cohort included 62,866 patients with a mean age of 85.9 ± 4.6 years and 58.8% were women. The ICU admission rates were 22.5%, 2.6% and 2.3% in USA, Australia, and Israel, respectively. We constructed a model for ICU admissions based on the USA cohort (highest availability of ICU beds) and then calculated the expected probabilities for the Israeli and Australian cohorts. For the patients in the highest quintile of the admission model, actual ICU admission rates were 67.6% in USA, 22.1% in Australia and 6.0% in Israel. Of these, in-hospital death rates were 52.3% in Israel, 29.8% in Australia, and 22.1% in USA. Two years after hospital discharge, the survival rates in the USA and Australia were 53%, while in Israel 48%.

Conclusion

ICU admission of adults ≥ 80 years is associated with increased in-hospital survival compared to ward admission, but survival rates 2 years later are similar.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-00994-x.

Does Unprecedented ICU Capacity Strain, As Experienced During the COVID-19 Pandemic, Impact Patient Outcome?

OBJECTIVES

To determine whether patients admitted to an ICU during times of unprecedented ICU capacity strain, during the COVID-19 pandemic in the United Kingdom, experienced a higher risk of death.

DESIGN

Multicenter, observational cohort study using routine clinical audit data.

SETTING

Adult general ICUs participating the Intensive Care National Audit & Research Centre Case Mix Programme in England, Wales, and Northern Ireland.

PATIENTS

One-hundred thirty-thousand six-hundred eighty-nine patients admitted to 210 adult general ICUs in 207 hospitals.

INTERVENTIONS

Multilevel, mixed effects, logistic regression models were used to examine the relationship between levels of ICU capacity strain on the day of admission (typical low, typical, typical high, pandemic high, and pandemic extreme) and risk-adjusted hospital mortality.

MEASUREMENTS AND MAIN RESULTS

In adjusted analyses, compared with patients admitted during periods of typical ICU capacity strain, we found that COVID-19 patients admitted during periods of pandemic high or pandemic extreme ICU capacity strain during the first wave had no difference in hospital mortality, whereas those admitted during the pandemic high or pandemic extreme ICU capacity strain in the second wave had a 17% (odds ratio [OR], 1.17; 95% CI, 1.05-1.30) and 15% (OR, 1.15; 95% CI, 1.00-1.31) higher odds of hospital mortality, respectively. For non-COVID-19 patients, there was little difference in trend between waves, with those admitted during periods of pandemic high and pandemic extreme ICU capacity strain having 16% (OR, 1.16; 95% CI, 1.08-1.25) and 30% (OR, 1.30; 95% CI, 1.14-1.48) higher overall odds of acute hospital mortality, respectively.

CONCLUSIONS

For patients admitted to ICU during the pandemic, unprecedented levels of ICU capacity strain were significantly associated with higher acute hospital mortality, after accounting for differences in baseline characteristics. Further study into possible differences in the provision of care and outcome for COVID-19 and non-COVID-19 patients is needed.

Probiotics in the Intensive Care Unit

The understanding of the gut microbiome in health and disease has shown tremendous progress in the last decade. Shaped and balanced throughout life, the gut microbiome is intricately related to the local and systemic immune system and a multitude of mechanisms through which the gut microbiome contributes to the host’s defense against pathogens have been revealed. Similarly, a plethora of negative consequences, such as superinfections and an increased rate of hospital re-admissions, have been identified when the gut microbiome is disturbed by disease or by the iatrogenic effects of antibiotic treatment and other interventions. In this review, we describe the role that probiotics may play in the intensive care unit (ICU). We discuss what is known about the gut microbiome of the critically ill, and the concept of probiotic intervention to positively modulate the gut microbiome. We summarize the evidence derived from randomized clinical trials in this context, with a focus on the prevention of ventilator-associated pneumonia. Finally, we consider what lessons we can learn in terms of the current challenges, efficacy and safety of probiotics in the ICU and what we may expect from the future. Throughout the review, we highlight studies that have provided conceptual advances to the field or have revealed a specific mechanism; this narrative review is not intended as a comprehensive summary of the literature.

Discrepancy between the Demand and Supply of Intensive Care Unit Beds in South Korea from 2011 to 2019: A Cross-Sectional Analysis

PURPOSE

Intensive care unit (ICU) bed availability is key to critical patient care. In many countries, older patients generally account for a significant proportion of hospitalizations and ICU admissions. Therefore, considering the rapidly increasing aging population in South Korea, it is important to establish whether the demand for critical care is currently met by available ICU beds.

MATERIALS AND METHODS

We evaluated a 9-year trend in ICU bed supply and ICU length of stay in South Korea between 2011 and 2019 in a population-based cross-sectional analysis, using data from the Korean Health Insurance Review & Assessment Service and Statistics database. We described the changes in ICU bed rates in adult (≥20 years) and older adult (≥65 years) populations. ICU length of stay was categorized similarly and was used to predict future ICU bed demands.

RESULTS

The ICU bed rate per 100000 adults increased from 18.5 in 2011 to 19.5 in 2019. In contrast, the ICU bed rate per 100000 older adults decreased from 127.6 in 2011 to 104.0 in 2019. ICU length of stay increased by 43.8% for adults and 55.6% for older adults. In 2019, the regional differences in the ICU bed rate nearly doubled, and the ICU length of stay increased six-fold. The ICU bed occupancy rate in South Korea is expected to rise to 102.7% in 2030.

CONCLUSION

The discrepancy between the demand and supply of ICU beds in South Korea requires urgent action to anticipate future ICU demands.

Profile of referrals to an intensive care unit from a regional hospital emergency centre in KwaZulu-Natal

Introduction

The objective was to describe the clinical characteristics, disease profile and outcome of patients referred from a regional hospital Emergency Centre (EC) to the Intensive Care Unit (ICU).

Methods

A retrospective review was performed using data extracted from the Integrated Critical Care Electronic Database (iCED). Data were extracted from the database with respect to patient characteristics, Society of Critical Care Medicine (SCCM) grading, and outcome of the ICU referral. Modified early warning scores (MEWS) were calculated from EC referral data.

Results

There were a total of 2187 referrals. Of these, 56.3% (1231/2187) were male. The mean age of referrals was 36 years. Of the referred patients, 41.5% (907/2187) were initially accepted for admission. A further 378 patients were accepted for admission after a follow up ICU review. Medical conditions accounted for the majority of patient referrals, followed by general surgery and trauma. Most patients initially accepted to ICU were classified as SCCM I and II and had a mean MEWS of 4. Almost half of the patients experienced a delay in admission, most commonly due to a lack of ICU bed availability. ICU mortality was 13.6% for patients admitted from the EC.

Discussion

The EC population referred to the ICU was young with a high burden of medical and trauma conditions. Decisions to accept patients to ICU are limited by available resources, and there was a need to apply ICU triage criteria. Delays in the transfer of ICU patients from the EC increase the workload and contribute to EC crowding.

Protocol and statistical analysis plan for the Pragmatic Investigation of optimaL Oxygen Targets (PILOT) clinical trial

INTRODUCTION

Mechanical ventilation of intensive care unit (ICU) patients universally involves titration of the fraction of inspired oxygen to maintain arterial oxygen saturation (SpO2). However, the optimal SpO2 target remains unknown.

METHODS AND ANALYSIS

The Pragmatic Investigation of optimaL Oxygen Targets (PILOT) trial is a prospective, unblinded, pragmatic, cluster-crossover trial being conducted in the emergency department (ED) and medical ICU at Vanderbilt University Medical Center in Nashville, Tennessee, USA. PILOT compares use of a lower SpO2 target (target 90% and goal range: 88%-92%), an intermediate SpO2 target (target 94% and goal range: 92%-96%) and a higher SpO2 target (target 98% and goal range: 96%-100%). The study units are assigned to a single SpO2 target (cluster-level allocation) for each 2-month study block, and the assigned SpO2 target switches every 2 months in a randomly generated sequence (cluster-level crossover). The primary outcome is ventilator-free days (VFDs) to study day 28, defined as the number of days alive and free of invasive mechanical ventilation from the final receipt of invasive mechanical ventilation through 28 days after enrolment.

ETHICS AND DISSEMINATION

The trial was approved by the Vanderbilt Institutional Review Board. The results will be submitted for publication in a peer-reviewed journal and presented at one or more scientific conferences.

TRIAL REGISTRATION NUMBER

The trial protocol was registered with ClinicalTrials.gov on 25 May 2018 prior to initiation of patient enrolment (ClinicalTrials.gov identifier: NCT03537937).

Critical illness in patients with metastatic cancer: a population-based cohort study of epidemiology and outcomes

The appropriateness of intensive care unit (ICU) admission of patients with metastatic cancer remains debated. We aimed to examine the short-term outcomes and their temporal pattern in critically ill patients with metastatic disease. We used state-wide data to identify hospitalizations aged ≥18 years with metastatic cancer admitted to ICU in Texas during 2010-2014. Multivariable logistic regression modeling was used to examine the factors associated with short-term mortality and its temporal trends among all ICU admissions and those undergoing mechanical ventilation. Among 136,644 ICU admissions with metastatic cancer, 50.8% were aged ≥65 years, with one or more organ failures present in 53.3% and mechanical ventilation was used in 11.1%. The crude short-term mortality among all ICU admissions and those mechanically ventilated was 28.1% and 62.0%, respectively. Discharge to home occurred in 57.1% of all ICU admissions. On adjusted analyses, short-term mortality increased with rising number of organ failures (adjusted OR (aOR) 1.399, 95% CI 1.374 to 1.425), while being lower with chemotherapy (aOR 0.467, 95% CI 0.432 to 0.506) and radiation therapy (aOR 0.832, 95% CI 0.749 to 0.924), and decreased over time (aOR 0.934 per year, 95% CI 0.924 to 0.945). Predictors of short-term mortality were largely similar among those undergoing mechanical ventilation. Most ICU admissions with metastatic cancer survived hospitalization, although short-term mortality was very high among those undergoing mechanical ventilation. Short-term mortality decreased over time and was lower among those receiving chemotherapy and radiation therapy. These findings support consideration of critical care in patients with metastatic cancer, but underscore the need to address patient-centered goals of care ahead of ICU admission.

Neurally adjusted ventilatory assist as a weaning mode for adults with invasive mechanical ventilation: a systematic review and meta-analysis

Background

Prolonged ventilatory support is associated with poor clinical outcomes. Partial support modes, especially pressure support ventilation, are frequently used in clinical practice but are associated with patient–ventilation asynchrony and deliver fixed levels of assist. Neurally adjusted ventilatory assist (NAVA), a mode of partial ventilatory assist that reduces patient–ventilator asynchrony, may be an alternative for weaning. However, the effects of NAVA on weaning outcomes in clinical practice are unclear.

Methods

We searched PubMed, Embase, Medline, and Cochrane Library from 2007 to December 2020. Randomized controlled trials and crossover trials that compared NAVA and other modes were identified in this study. The primary outcome was weaning success which was defined as the absence of ventilatory support for more than 48 h. Summary estimates of effect using odds ratio (OR) for dichotomous outcomes and mean difference (MD) for continuous outcomes with accompanying 95% confidence interval (CI) were expressed.

Results

Seven studies (n = 693 patients) were included. Regarding the primary outcome, patients weaned with NAVA had a higher success rate compared with other partial support modes (OR = 1.93; 95% CI 1.12 to 3.32; P = 0.02). For the secondary outcomes, NAVA may reduce duration of mechanical ventilation (MD = − 2.63; 95% CI − 4.22 to − 1.03; P = 0.001) and hospital mortality (OR = 0.58; 95% CI 0.40 to 0.84; P = 0.004) and prolongs ventilator-free days (MD = 3.48; 95% CI 0.97 to 6.00; P = 0.007) when compared with other modes.

Conclusions

Our study suggests that the NAVA mode may improve the rate of weaning success compared with other partial support modes for difficult to wean patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03644-z.

Women of reproductive age in a tertiary intensive care unit: indications, outcome and the impact of pregnancy-a retrospective cohort study

Background

To evaluate the indications for admission and mortality rates of women of reproductive age admitted to a tertiary Intensive Care Unit (ICU) and to compare the outcomes of obstetric and non-obstetric admissions.

Methods

A retrospective cohort study was performed, including all women aged 17–41 years admitted to a level 3 ICU in the Netherlands, between January 1, 2000 and January 1, 2016. Primary outcome was indication for admission and mortality. Mortality, length of stay (LOS), need for mechanical ventilation and APACHE II score were compared between obstetric and non-obstetric admissions. The obstetric group was further analyzed for maternal and perinatal outcomes.

Results

3461 women (median age 32 years) were included, with an overall mortality rate of 13.3%. The obstetric group consisted of 265 women (7.7%). The non-obstetric group (n = 3196) was admitted most often for cardiovascular disease (19.6%), followed by oncologic disease (15%). Mortality was the highest in women with oncologic disease (23.9%). The obstetric group had lower mortality compared to the non-obstetric group (4.9% vs. 14%, p < 0.001), despite higher APACHE II score (14 vs. 11, p < 0.001) and a higher ventilation rate (47.9% vs. 39%, p = 0.004). Major surgical or endovascular interventions, besides caesarean section, were performed in 46% of the obstetric group. Perinatal death occurred in 17.2% and of the surviving infants, 63.2% were born preterm and 45.1% required Neonatal Intensive Care Unit admission.

Conclusions

Cardiovascular disease is the most important indication for admission and oncologic disease is associated with highest mortality in women of reproductive age. Obstetric patients constitute a small percentage of all ICU admissions in a tertiary ICU center. They have lower mortality rates than non-obstetric young female patients, despite a more severe initial presentation. Nevertheless lasting maternal morbidity and perinatal mortality and morbidity is frequent.

Day-to-day progression of vital-sign circadian rhythms in the intensive care unit

Background

Disrupted vital-sign circadian rhythms in the intensive care unit (ICU) are associated with complications such as immune system disruption, delirium and increased patient mortality. However, the prevalence and extent of this disruption is not well understood. Tools for its detection are currently limited.

Methods

This paper evaluated and compared vital-sign circadian rhythms in systolic blood pressure, heart rate, respiratory rate and temperature. Comparisons were made between the cohort of patients who recovered from the ICU and those who did not, across three large, publicly available clinical databases. This comparison included a qualitative assessment of rhythm profiles, as well as quantitative metrics such as peak–nadir excursions and correlation to a demographically matched ‘recovered’ profile.

Results

Circadian rhythms were present at the cohort level in all vital signs throughout an ICU stay. Peak–nadir excursions and correlation to a ‘recovered’ profile were typically greater throughout an ICU stay in the cohort of patients who recovered, compared to the cohort of patients who did not.

Conclusions

These results suggest that vital-sign circadian rhythms are typically present at the cohort level throughout an ICU stay and that quantitative assessment of these rhythms may provide information of prognostic use in the ICU.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03574-w.

Monitoring deep-tissue oxygenation with a millimeter-scale ultrasonic implant

Vascular complications following solid organ transplantation may lead to graft ischemia, dysfunction or loss. Imaging approaches can provide intermittent assessments of graft perfusion, but require highly skilled practitioners and do not directly assess graft oxygenation. Existing systems for monitoring tissue oxygenation are limited by the need for wired connections, the inability to provide real-time data or operation restricted to surface tissues. Here, we present a minimally invasive system to monitor deep-tissue O₂ that reports continuous real-time data from centimeter-scale depths in sheep and up to a 10-cm depth in ex vivo porcine tissue. The system is composed of a millimeter-sized, wireless, ultrasound-powered implantable luminescence O₂ sensor and an external transceiver for bidirectional data transfer, enabling deep-tissue oxygenation monitoring for surgical or critical care indications.

Characteristics and outcomes of patients admitted to adult intensive care units in Hong Kong: a population retrospective cohort study from 2008 to 2018

Background

Globally, mortality rates of patients admitted to the intensive care unit (ICU) have decreased over the last two decades. However, evaluations of the temporal trends in the characteristics and outcomes of ICU patients in Asia are limited. The objective of this study was to describe the characteristics and risk adjusted outcomes of all patients admitted to publicly funded ICUs in Hong Kong over a 11-year period. The secondary objective was to validate the predictive performance of Acute Physiology And Chronic Health Evaluation (APACHE) IV for ICU patients in Hong Kong.

Methods

This was an 11-year population-based retrospective study of all patients admitted to adult general (mixed medical-surgical) intensive care units in Hong Kong public hospitals. ICU patients were identified from a population electronic health record database. Prospectively collected APACHE IV data and clinical outcomes were analysed.

Results

From 1 April 2008 to 31 March 2019, there were a total of 133,858 adult ICU admissions in Hong Kong public hospitals. During this time, annual ICU admissions increased from 11,267 to 14,068, whilst hospital mortality decreased from 19.7 to 14.3%. The APACHE IV standard mortality ratio (SMR) decreased from 0.81 to 0.65 during the same period. Linear regression demonstrated that APACHE IV SMR changed by − 0.15 (95% CI − 0.18 to − 0.11) per year (Pearson’s R = − 0.951, p < 0.001). Observed median ICU length of stay was shorter than that predicted by APACHE IV (1.98 vs. 4.77, p < 0.001). C-statistic for APACHE IV to predict hospital mortality was 0.889 (95% CI 0.887 to 0.891) whilst calibration was limited (Hosmer–Lemeshow test p < 0.001).

Conclusions

Despite relatively modest per capita health expenditure, and a small number of ICU beds per population, Hong Kong consistently provides a high-quality and efficient ICU service. Number of adult ICU admissions has increased, whilst adjusted mortality has decreased over the last decade. Although APACHE IV had good discrimination for hospital mortality, it overestimated hospital mortality of critically ill patients in Hong Kong.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-020-00513-9.

COVID-19 in critical care: epidemiology of the first epidemic wave across England, Wales and Northern Ireland

PURPOSE

To describe critical care patients with COVID-19 across England, Wales and Northern Ireland and compare them with a historic cohort of patients with other viral pneumonias (non-COVID-19) and with international cohorts of COVID-19.

METHODS

Extracted data on patient characteristics, acute illness severity, organ support and outcomes from the Case Mix Programme, the national clinical audit for adult critical care, for a prospective cohort of patients with COVID-19 (February to August 2020) are compared with a recent retrospective cohort of patients with other viral pneumonias (non-COVID-19) (2017-2019) and with other international cohorts of critical care patients with COVID-19, the latter identified from published reports.

RESULTS

10,834 patients with COVID-19 (70.1% male, median age 60 years, 32.6% non-white ethnicity, 39.4% obese, 8.2% at least one serious comorbidity) were admitted across 289 critical care units. Of these, 36.9% had a PaO₂/FiO₂ ratio of ≤ 13.3 kPa (≤ 100 mmHg) consistent with severe ARDS and 72% received invasive ventilation. Acute hospital mortality was 42%, higher than for 5782 critical care patients with other viral pneumonias (non-COVID-19) (24.7%), and most COVID-19 deaths (88.7%) occurred before 30 days. Meaningful international comparisons were limited due to lack of standardised reporting.

CONCLUSION

Critical care patients with COVID-19 were disproportionately non-white, from more deprived areas and more likely to be male and obese. Conventional severity scoring appeared not to adequately reflect their acute severity, with the distribution across PaO₂/FiO₂ ratio categories indicating acutely severe respiratory disease. Critical care patients with COVID-19 experience high mortality and place a great burden on critical care services.

Hydrocortisone mitigates ICU-AW by fine-tuning of muscle atrophic and hypertrophic signaling pathways in a sepsis model with limb immobilization

AIMS

Intensive care unit-acquired weakness (ICU-AW) is a complex spectrum of disability that delays recovery of critically ill-immobilized patients with sepsis. Much discrepancy remain on the use of corticosteroids and their impact on muscle regeneration in critical illness management. Therefore, the aim of this study is to investigate whether hydrocortisone (HCT) modulates muscle mass turnover in ICU-AW induced by sepsis with limb immobilization (SI).

MAIN METHODS

Sepsis by cecal ligation puncture (CLP) with forelimb-immobilization were performed in rats. The study consisted of four groups: Sham (left forelimb-immobilization), Sham HCT (left forelimb-immobilization + HCT), SI (CLP + left forelimb-immobilization) and SI HCT (CLP + left forelimb-immobilization + HCT). Motor force, blood and muscle sampling were assessed.

KEY FINDINGS

HCT prevented body weight loss associated with SI and attenuated systemic and muscular inflammation. Besides, myosin was restituted in SI HCT group in conjunction to muscle mass and strength restoration. Pro-hypertrophic calcineurin (PP2B-Aβ) and nuclear factor of activated T-cells C3 (NFATc3) but not protein kinase B (Akt) were re-activated by HCT. Finally, pro-atrophic extracellular signal-regulated kinases (ERK1/2) and p38 mitogen-activated protein kinases (p38) but not nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) were inhibited in SI HCT group.

SIGNIFICANCE

This study unravels new molecular events thought to control muscle protein synthesis in ICU-AW induced by sepsis and limb immobilization. HCT has a potential to fine-tune muscle-signaling pathways and to reduce the negative outcomes of ICU-AW.

Rates, predictors, and mortality of sepsis-associated acute kidney injury: a systematic review and meta-analysis

BACKGROUND

Due to the high incidence and mortality of sepsis-associated acute kidney injury, a significant number of studies have explored the causes of sepsis-associated acute kidney injury (AKI). However, the opinions on relevant predictive risk factors remain inconclusive. This study aimed to provide a systematic review and meta-analysis to determine the predisposing factors for sepsis-associated AKI.

METHOD

A systematic literature search was performed in the Medline, Embase, Cochrane Library, PubMed, and Web of Science, databases, with an end-date of 25th May 2019. Valid data were retrieved in compliance with specific inclusion and exclusion criteria.

RESULT

Forty-seven observational studies were included for analysis, achieving a cumulative patient number of 55,911. The highest incidence of AKI was caused by septic shock. Thirty-one potential risk factors were included in the meta-analysis. Analysis showed that 20 factors were statistically significant. The odds ratio (OR) and 95% confidence interval (CI), as well as the prevalence of the most frequently-seen predisposing factors for sepsis-associated AKI, were as follows: septic shock [2.88 (2.36-3.52), 60.47%], hypertension [1.43 (1.20-1.70), 38.39%], diabetes mellitus [1.59 (1.47-1.71), 27.57%], abdominal infection [1.44 (1.32-1.58), 30.87%], the administration of vasopressors [2.95 (1.67-5.22), 64.61%], the administration of vasoactive drugs [3.85 (1.89-7.87), 63.22%], mechanical ventilation [1.64 (1.24-2.16), 68.00%], positive results from blood culture [1.60 (1.35-1.89), 41.19%], and a history of smoking [1.60 (1.09-2.36), 43.09%]. Other risk factors included cardiovascular diseases, coronary artery diseases, liver diseases, unknown infections, the administration of diuretics and ACEI/ARB, the infection caused by gram-negative bacteria, and organ transplantation.

CONCLUSION

Risk factors of S-AKI arise from a wide range of sources, making it difficult to predict and prevent this condition. Comorbidities, and certain drugs, are the main risk factors for S-AKI. Our review can provide guidance on the application of interventions to reduce the risks associated with sepsis-associated acute kidney injury and can also be used to tailor patient-specific treatment plans and management strategies in clinical practice.

Conditional Survival With Increasing Duration of ICU Admission: An Observational Study of Three Intensive Care Databases

Supplemental Digital Content is available in the text.

Objectives:

Prolonged admissions to an ICU are associated with high resource utilization and personal cost to the patient. Previous reports suggest increasing length of stay may be associated with poor outcomes. Conditional survival represents the probability of future survival after a defined period of treatment on an ICU providing a description of how prognosis evolves over time. Our objective was to describe conditional survival as length of ICU stay increased.

Design:

Retrospective observational cohort study of three large intensive care databases.

Setting:

Three intensive care databases, two in the United States (Medical Information Mart for Intensive Care III and electronic ICU) and one in United Kingdom (Post Intensive Care Risk-Adjusted Alerting and Monitoring).

Patients:

Index admissions to intensive care for patients 18 years or older.

Interventions:

None.

Measurements and Main Results:

A total of 11,648, 38,532, and 165,125 index admissions were analyzed from Post Intensive Care Risk-Adjusted Alerting and Monitoring, Medical Information Mart for Intensive Care III and electronic ICU databases respectively. In all three cohorts, conditional survival declined over the first 5–10 days after ICU admission and changed little thereafter. In patients greater than or equal to 75 years old conditional survival continued to decline with increasing length of stay.

Conclusions:

After an initial period of 5–10 days, probability of future survival does not decrease with increasing length of stay in unselected patients admitted to ICUs. These findings were consistent between the three populations and suggest that a prolonged admission to an ICU is not a reason for a pessimism in younger patients but may indicate a poor prognosis in the older population.

Comparison of Care Patterns and Rehospitalizations for Mechanically Ventilated Patients in New York and Ontario

RATIONALE

Mechanically ventilated patients require complex care and are at high risk for rehospitalization, but different systems of care may result in different hospital discharge practices and rates of rehospitalization.

OBJECTIVES

To compare lengths of hospitalization, discharge patterns, and rehospitalization rates in New York in the United States and Ontario in Canada.

METHODS

We conducted a retrospective cohort study of mechanically ventilated patients who survived an acute care hospitalization in New York or Ontario from 2010 to 2012, using linkable administrative healthcare data.

RESULTS

The primary outcome was the cumulative incidence of first rehospitalization within 30 days of discharge, accounting for the competing risk of death. Of 71,063 mechanically ventilated patients in New York, and 41,875 in Ontario who survived to hospital discharge, median length of initial hospital stay was similar in New York and Ontario (15 d, interquartile range = 8-28 vs. 16 d [9-30]), but was systematically shorter in New York when stratified by patient subgroups of different illness severity. Fewer patients in New York were discharged directly home (53.6% vs. 71.4%). Of patients in New York, 15,527 (cumulative incidence 21.9%) had a first rehospitalization within 30 days versus 5,580 (cumulative incidence 13.3%) in Ontario (P < 0.001). Incidence of rehospitalization was higher in New York across all subgroups assessed, with the greatest differences among patients with a tracheostomy (29.8% vs. 13.3%, P < 0.001), those who received dialysis during the hospitalization (31.9% vs. 17.4%, P < 0.001), and for patients not discharged directly home (27.6% vs. 13.3%, P < 0.001).

CONCLUSIONS

Care patterns for mechanically ventilated patients in New York and Ontario are very different; mechanically ventilated patients who survive to hospital discharge in New York have shorter hospital stays, with higher rehospitalization rates within 30 days compared with Ontario.

Empirical prescribing of penicillin G/V reduces risk of readmission of hospitalized patients with community-acquired pneumonia in Norway: a retrospective observational study

BACKGROUND

Norwegian guideline recommendations on first-line empirical antibiotic prescribing in hospitalised patients with community-acquired pneumonia (CAP) are penicillin G/V in monotherapy, or penicillin G in combination with gentamicin (or cefotaxime) in severely ill patients. The aim of this study was to explore how different empirical antibiotic treatments impact on length of hospital stay (LOS) and 30-day hospital readmission. A secondary aim was to describe median intravenous- and total treatment duration.

METHODS

We included CAP patients (≥18 years age) hospitalised in North Norway during 2010 and 2012 in a retrospective study. Patients with negative chest x-ray, malignancies or immunosuppression or frequent readmissions were excluded. We collected data on patient characteristics, empirical antibiotic prescribing, treatment duration and clinical outcomes from electronic patient records and the hospital administrative system. We used directed acyclic graphs for statistical model selection, and analysed data with mulitvariable logistic and linear regression.

RESULTS

We included 651 patients. Median age was 77 years [IQR; 64-84] and 46.5% were female. Median LOS was 4 days [IQR; 3-6], 30-day readmission rate was 14.4% and 30-day mortality rate was 6.9%. Penicillin G/V were empirically prescribed in monotherapy in 51.5% of patients, penicillin G and gentamicin in combination in 22.9% and other antibiotics in 25.6% of patients. Prescribing other antibiotics than penicillin G/V monotherapy was associated with increased risk of readmission [OR 1.9, 95% CI; 1.08-3.42]. Empirical antibiotic prescribing was not associated with LOS. Median intravenous- and total treatment duration was 3.0 [IQR; 2-5] and 11.0 [IQR; 9.8-13] days.

CONCLUSIONS

Our findings show that empirical prescribing with penicillin G/V in monotherapy in hospitalised non-severe CAP-patients, without complicating factors such as malignancy, immunosuppression and frequent readmission, is associated with lower risk of 30-day readmission compared to other antibiotic treatments. Median total treatment duration exceeds treatment recommendations.

COVID-19 and US Health Financing: Perils and Possibilities

While the COVID-19 pandemic presents every nation with challenges, the United States’ underfunded public health infrastructure, fragmented medical care system, and inadequate social protections impose particular impediments to mitigating and managing the outbreak. Years of inadequate funding of the nation’s federal, state, and local public health agencies, together with mismanagement by the Trump administration, hampered the early response to the epidemic. Meanwhile, barriers to care faced by uninsured and underinsured individuals in the United States could deter COVID-19 care and hamper containment efforts, and lead to adverse medical and financial outcomes for infected individuals and their families, particularly those from disadvantaged groups. While the United States has a relatively generous supply of Intensive Care Unit beds and most other health care infrastructure, such medical resources are often unevenly distributed or deployed, leaving some areas ill-prepared for a severe respiratory epidemic. These deficiencies and shortfalls have stimulated a debate about policy solutions. Recent legislation, for instance, expanded coverage for testing for COVID-19 for the uninsured and underinsured, and additional reforms have been proposed. However comprehensive health care reform – for example, via national health insurance – is needed to provide full protection to American families during the COVID-19 outbreak and in its aftermath.

Association between age and acute respiratory distress syndrome development and mortality following trauma

BACKGROUND

Improved understanding of the relationship between patient age and acute respiratory distress syndrome (ARDS) development and mortality following traumatic injury may help facilitate generation of new hypotheses about ARDS pathophysiology and the role of novel treatments to improve outcomes across the age spectrum.

METHODS

We conducted a retrospective cohort study of trauma patients included in the National Trauma Data Bank who were admitted to an intensive care unit from 2007 to 2016. We determined ARDS incidence and mortality across eight age groups for the entire 10-year study period and by year. We used generalized linear Poisson regression models adjusted for underlying mortality risk (injury mechanism, Injury Severity Score, admission Glasgow Coma Scale score, admission heart rate, and admission hypotension).

RESULTS

Acute respiratory distress syndrome occurred in 3.1% of 1,297,190 trauma encounters. Acute respiratory distress syndrome incidence was lowest among pediatric patients and highest among adults aged 35 to 64 years. Acute respiratory distress syndrome mortality was highest among patients 80 years or older (43.9%), followed by 65 to 79 years (30.6%) and 4 years or younger (25.3%). The relative risk of mortality associated with ARDS was highest among the pediatric age groups, with an adjusted relative risk (aRR) of 2.06 (95% confidence interval [CI], 1.72-2.70) among patients 4 years or younger compared with an aRR of 1.51 (95% CI, 1.42-1.62) for the entire cohort. Acute respiratory distress syndrome mortality increased over the 10-year study period (aRR, 1.03 per year; 95% CI, 1.02-1.05 per year), whereas all-cause mortality decreased (aRR, 0.98 per year; 95% CI, 0.98-0.99 per year).

CONCLUSIONS

While ARDS development following traumatic injury was most common in middle-aged adults, patients 4 years or younger and 65 years or older with ARDS experienced the highest burden of mortality. Children 4 years or younger were disproportionately affected by ARDS relative to their low underlying mortality following trauma that was not complicated by ARDS. Acute respiratory distress syndrome-associated mortality following trauma has worsened over the past decade, emphasizing the need for new prevention and treatment strategies.

LEVEL OF EVIDENCE

Prognostic/epidemiological study, level III.

Development and validation of early warning score system: A systematic literature review

OBJECTIVES

This review aims to: 1) evaluate the quality of model reporting, 2) provide an overview of methodology for developing and validating Early Warning Score Systems (EWSs) for adult patients in acute care settings, and 3) highlight the strengths and limitations of the methodologies, as well as identify future directions for EWS derivation and validation studies.

METHODOLOGY

A systematic search was conducted in PubMed, Cochrane Library, and CINAHL. Only peer reviewed articles and clinical guidelines regarding developing and validating EWSs for adult patients in acute care settings were included. 615 articles were extracted and reviewed by five of the authors. Selected studies were evaluated based on the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) checklist. The studies were analyzed according to their study design, predictor selection, outcome measurement, methodology of modeling, and validation strategy.

RESULTS

A total of 29 articles were included in the final analysis. Twenty-six articles reported on the development and validation of a new EWS, while three reported on validation and model modification. Only eight studies met more than 75% of the items in the TRIPOD checklist. Three major techniques were utilized among the studies to inform their predictive algorithms: 1) clinical-consensus models (n = 6), 2) regression models (n = 15), and 3) tree models (n = 5). The number of predictors included in the EWSs varied from 3 to 72 with a median of seven. Twenty-eight models included vital signs, while 11 included lab data. Pulse oximetry, mental status, and other variables extracted from electronic health records (EHRs) were among other frequently used predictors. In-hospital mortality, unplanned transfer to the intensive care unit (ICU), and cardiac arrest were commonly used clinical outcomes. Twenty-eight studies conducted a form of model validation either within the study or against other widely-used EWSs. Only three studies validated their model using an external database separate from the derived database.

CONCLUSION

This literature review demonstrates that the characteristics of the cohort, predictors, and outcome selection, as well as the metrics for model validation, vary greatly across EWS studies. There is no consensus on the optimal strategy for developing such algorithms since data-driven models with acceptable predictive accuracy are often site-specific. A standardized checklist for clinical prediction model reporting exists, but few studies have included reporting aligned with it in their publications. Data-driven models are subjected to biases in the use of EHR data, thus it is particularly important to provide detailed study protocols and acknowledge, leverage, or reduce potential biases of the data used for EWS development to improve transparency and generalizability.

Intensive care admissions and outcomes associated with short-term exposure to ambient air pollution: a time series analysis

PURPOSE

Short-term exposure to outdoor air pollution has been positively associated with numerous measures of acute morbidity and mortality, most consistently as excess cardiorespiratory disease associated with fine particulate matter (PM_2.5), particularly in vulnerable populations. It is unknown if the critically ill, a vulnerable population with high levels of cardiorespiratory disease, is affected by air pollution.

METHODS

We performed a time series analysis of emergency cardiorespiratory, stroke and sepsis intensive care (ICU) admissions for the years 2008-2016, using data from the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS-APD). Case-crossover analysis was conducted to assess the relationship between air pollution and the frequency and severity of ICU admissions having adjusted for temperature, humidity, public holidays and influenza activity.

RESULTS

46,965 episodes in 87 separate ICUs were analysed. We found no statistically significant associations with admission counts. However, ICU admissions ending in death within 30 days were significantly positively associated with short-term exposure to PM_2.5 [RR 1.18, 95% confidence interval (CI) 1.02-1.37, per 10 µg/m³ increase]. This association was more pronounced in those aged 65 and over (RR 1.33, 95% CI 1.11-1.58, per 10 µg/m³).

CONCLUSIONS

Increased ICU mortality was associated with higher levels of PM_2.5. Larger studies are required to determine if the frequency of ICU admissions is positively associated with short-term exposure to air pollution.