Nutrition delivery across hospitalisation in critically ill patients with COVID-19: An observational study of the Australian experience

BACKGROUND

Data on nutrition delivery over the whole hospital admission in critically ill patients with COVID-19 are scarce, particularly in the Australian setting.

OBJECTIVES

The objective of this study was to describe nutrition delivery in critically ill patients admitted to Australian intensive care units (ICUs) with coronavirus disease 2019 (COVID-19), with a focus on post-ICU nutrition practices.

METHODS

A multicentre observational study conducted at nine sites included adult patients with a positive COVID-19 diagnosis admitted to the ICU for >24 h and discharged to an acute ward over a 12-month recruitment period from 1 March 2020. Data were extracted on baseline characteristics and clinical outcomes. Nutrition practice data from the ICU and weekly in the post-ICU ward (up to week four) included route of feeding, presence of nutrition-impacting symptoms, and nutrition support received.

RESULTS

A total of 103 patients were included (71% male, age: 58 ± 14 years, body mass index: 30±7 kg/m2), of whom 41.7% (n = 43) received mechanical ventilation within 14 days of ICU admission. While oral nutrition was received by more patients at any time point in the ICU (n = 93, 91.2% of patients) than enteral nutrition (EN) (n = 43, 42.2%) or parenteral nutrition (PN) (n = 2, 2.0%), EN was delivered for a greater duration of time (69.6% feeding days) than oral and PN (29.7% and 0.7%, respectively). More patients received oral intake than the other modes in the post-ICU ward (n = 95, 95.0%), and 40.0% (n = 38/95) of patients were receiving oral nutrition supplements. In the week after ICU discharge, 51.0% of patients (n = 51) had at least one nutrition-impacting symptom, most commonly a reduced appetite (n = 25; 24.5%) or dysphagia (n = 16; 15.7%).

CONCLUSION

Critically ill patients during the COVID-19 pandemic in Australia were more likely to receive oral nutrition than artificial nutrition support at any time point both in the ICU and in the post-ICU ward, whereas EN was provided for a greater duration when it was prescribed. Nutrition-impacting symptoms were common.

Dose equivalence for metaraminol and noradrenaline - A retrospective analysis

BACKGROUND

Noradrenaline and metaraminol are commonly used vasopressors in critically ill patients. However, little is known of their dose equivalence.

METHODS

We conducted a single centre retrospective cohort study of all ICU patients who transitioned from metaraminol to noradrenaline infusions between August 26, 2016 and December 31, 2020. Patients receiving additional vasoactive drug infusion were excluded. Dose equivalence was calculated based on the last hour metaraminol dose (in μg/min) and the first hour noradrenaline dose (in μg/min) with the closest matched mean arterial pressure (MAP). Sensitivity analyses were performed on patients with acute kidney injury (AKI), sepsis and mechanical ventilation.

RESULTS

We studied 195 patients. The median conversion ratio of metaraminol to noradrenaline was 12.5:1 (IQR 7.5-20.0) for the overall cohort. However, the coefficient of variation was 77% and standard deviation was 11.8. Conversion ratios were unaffected by sepsis or mechanical ventilation but increased (14:1) with AKI. One in five patients had a MAP decrease of >10 mmHg during the transition period from metaraminol to noradrenaline. Post-transition noradrenaline dose (p < 0.001) and AKI (p = 0.045) were independently associated with metaraminol dose. The proportion of variation in noradrenaline dose predicted from metaraminol dose was low (R2 = 0.545).

CONCLUSIONS

The median dose equivalence for metaraminol and noradrenaline in this study was 12.5:1. However, there was significant variance in dose equivalence, only half the proportion of variation in noradrenaline infusion dose was predicted by metaraminol dose, and conversion-associated hypotension was common.

Magnitude and time to peak oxygenation effect of prone positioning in ventilated adults with COVID-19 related acute hypoxemic respiratory failure

BACKGROUND

Prone positioning may improve oxygenation in acute hypoxemic respiratory failure and was widely adopted in COVID-19 patients. However, the magnitude and timing of its peak oxygenation effect remain uncertain with the optimum dosage unknown. Therefore, we aimed to investigate the magnitude of the peak effect of prone positioning on the PaO2 :FiO2 ratio during prone and secondly, the time to peak oxygenation.

METHODS

Multi-centre, observational study of invasively ventilated adults with acute hypoxemic respiratory failure secondary to COVID-19 treated with prone positioning. Baseline characteristics, prone positioning and patient outcome data were collected. All arterial blood gas (ABG) data during supine, prone and after return to supine position were analysed. The magnitude of peak PaO2 :FiO2 ratio effect and time to peak PaO2 :FIO2 ratio effect was measured.

RESULTS

We studied 220 patients (mean age 54 years) and 548 prone episodes. Prone positioning was applied for a mean (±SD) 3 (±2) times and 16 (±3) hours per episode. Pre-proning PaO2 :FIO2 ratio was 137 (±49) for all prone episodes. During the first episode. the mean PaO2 :FIO2 ratio increased from 125 to a peak of 196 (p < .001). Peak effect was achieved during the first episode, after 9 (±5) hours in prone position and maintained until return to supine position.

CONCLUSIONS

In ventilated adults with COVID-19 acute hypoxemic respiratory failure, peak PaO2 :FIO2 ratio effect occurred during the first prone positioning episode and after 9 h. Subsequent episodes also improved oxygenation but with diminished effect on PaO2 :FIO2 ratio. This information can help guide the number and duration of prone positioning episodes.

PRECISION-TBI: a study protocol for a vanguard prospective cohort study to enhance understanding and management of moderate to severe traumatic brain injury in Australia

INTRODUCTION

Traumatic brain injury (TBI) is a heterogeneous condition in terms of pathophysiology and clinical course. Outcomes from moderate to severe TBI (msTBI) remain poor despite concerted research efforts. The heterogeneity of clinical management represents a barrier to progress in this area. PRECISION-TBI is a prospective, observational, cohort study that will establish a clinical research network across major neurotrauma centres in Australia. This network will enable the ongoing collection of injury and clinical management data from patients with msTBI, to quantify variations in processes of care between sites. It will also pilot high-frequency data collection and analysis techniques, novel clinical interventions, and comparative effectiveness methodology.

METHODS AND ANALYSIS

PRECISION-TBI will initially enrol 300 patients with msTBI with Glasgow Coma Scale (GCS) <13 requiring intensive care unit (ICU) admission for invasive neuromonitoring from 10 Australian neurotrauma centres. Demographic data and process of care data (eg, prehospital, emergency and surgical intervention variables) will be collected. Clinical data will include prehospital and emergency department vital signs, and ICU physiological variables in the form of high frequency neuromonitoring data. ICU treatment data will also be collected for specific aspects of msTBI care. Six-month extended Glasgow Outcome Scores (GOSE) will be collected as the key outcome. Statistical analysis will focus on measures of between and within-site variation. Reports documenting performance on selected key quality indicators will be provided to participating sites.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from The Alfred Human Research Ethics Committee (Alfred Health, Melbourne, Australia). All eligible participants will be included in the study under a waiver of consent (hospital data collection) and opt-out (6 months follow-up). Brochures explaining the rationale of the study will be provided to all participants and/or an appropriate medical treatment decision-maker, who can act on the patient's behalf if they lack capacity. Study findings will be disseminated by peer-review publications.

TRIAL REGISTRATION NUMBER

NCT05855252.

Association Between Early External Ventricular Drain Insertion and Functional Outcomes 6 Months Following Moderate-to-Severe Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading global cause of morbidity and mortality. Intracranial hypertension following moderate-to-severe TBI (m-sTBI) is a potentially modifiable secondary cerebral insult and one of the central therapeutic targets of contemporary neurocritical care. External ventricular drain (EVD) insertion is a common therapeutic intervention used to control intracranial hypertension and attenuate secondary brain injury. However, the optimal timing of EVD insertion in the setting of m-sTBI is uncertain and practice variation is widespread. Therefore, we aimed to assess if there is an association between timing of EVD placement and functional neurological outcome at 6 months post m-sTBI. We pooled individual patient data for all relevant harmonizable variables from the Erythropoietin in Traumatic Brain Injury (EPO-TBI) and Prophylactic Hypothermia Trial to Lessen Traumatic Brain Injury (POLAR) randomized control trials, and the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) Core Study version 3.0 and Australia-Europe NeuroTrauma Effectiveness Research in TBI (Oz-ENTER) prospective observational studies to create a combined dataset. The Glasgow Coma Scale (GCS) score was used to define TBI severity and we included all patients admitted to an intensive care unit with a GCS ≤12, who were 15 years or older and underwent EVD placement within 7 days of injury. We used hierarchical multi-variable logistic regression models to study the association between EVD insertion within 24 h of injury (early) compared with EVD insertion more than 24 h after injury (late) and 6-month functional neurological outcome measured using the Glasgow Outcome Score Extended (GOSE). In total, 2536 patients were assessed. Of these, 502 (20%) underwent early EVD insertion and 145 (6%) underwent late EVD insertion. Following adjustment for the IMPACT (International Mission for Prognosis and Analysis of Clinical Trials in TBI) score extended (Core + CT), sex, injury severity score, study and treatment site, patients receiving a late EVD had higher odds of death or severe disability (GOSE 1-4) at 6 months follow-up than those receiving an early EVD adjusted odds ratio; 95% confidence interval, 2.14; 1.22-3.76; p = 0.008. Our study suggests that in patients with m-sTBI where an EVD is needed, early (≤ 24 h post-injury) insertion may result in better long-term functional outcomes. This finding supports future prospective investigation in this area.

An exploration of intensive care nurses' perceptions of workload in providing extracorporeal membrane oxygenation (ECMO) support: A descriptive qualitative study

BACKGROUND

There is increasing use of extracorporeal membrane oxygenation (ECMO) in intensive care, where nurses provide the majority of the required ongoing care of cannulas, circuit, and console. Limited evidence currently exists that details nursing perspectives, experiences, and challenges with workload in the provision of ECMO care.

OBJECTIVE

The objective of this study was to investigate intensive care nurses' perceptions of workload in providing specialist ECMO therapy and care in a high-volume ECMO centre.

METHODS

The study used a qualitative descriptive methodology through semistructured interviews. Data were analysed using an inductive thematic analysis approach following Braun and Clarke's iterative process. This study was conducted in an intensive care unit within an Australian public, quaternary, university-affiliated hospital, which provides specialist state-wide service for ECMO.

FINDINGS

Thirty ECMO-specialist trained intensive care nurses were interviewed. This study identified three key themes: (i) opportunity; (ii) knowledge and responsibilities; and (iii) systems and structures impacting on intensive care nurses' workload in providing ECMO supportive therapy.

CONCLUSIONS

Intensive care nurses require advanced clinical and critical thinking skills. Intensive care nurses are motivated and engaged to learn and acquire ECMO skills and competency as part of their ongoing professional development. Providing bedside ECMO management requires constant monitoring and surveillance from nurses to care for the one of the most critically unwell patient populations in the intensive care unit setting. As such, ECMO nursing services require a suitably trained and educated workforce of intensive care trained nurses. ECMO services provide clinical development opportunities for nurses, increase their scope of practice, and create advanced practice-specialist roles.

Neuromuscular blockade and oxygenation changes during prone positioning in COVID-19

PURPOSE

Neuromuscular blockers (NMBs) are often used during prone positioning to facilitate mechanical ventilation in COVID-19 related ARDS. However, their impact on oxygenation is uncertain.

METHODS

Multi-centre observational study of invasively ventilated COVID-19 ARDS adults treated with prone positioning. We collected data on baseline characteristics, prone positioning, NMB use and patient outcome. We assessed arterial blood gas data during supine and prone positioning and after return to the supine position.

RESULTS

We studied 548 prone episodes in 220 patients (mean age 54 years, 61% male) of whom 164 (75%) received NMBs. Mean PaO2:FiO2 (P/F ratio) during the first prone episode with NMBs reached 208 ± 63 mmHg compared with 161 ± 66 mmHg without NMBs (Δmean = 47 ± 5 mmHg) for an absolute increase from baseline of 76 ± 56 mmHg versus 55 ± 56 mmHg (padj < 0.001). The mean P/F ratio on return to the supine position was 190 ± 63 mmHg in the NMB group versus 141 ± 64 mmHg in the non-NMB group for an absolute increase from baseline of 59 ± 58 mmHg versus 34 ± 56 mmHg (padj < 0.001).

CONCLUSION

During prone positioning, NMB is associated with increased oxygenation compared to non-NMB therapy, with a sustained effect on return to the supine position. These findings may help guide the use of NMB during prone positioning in COVID-19 ARDS.

Early management of adult traumatic spinal cord injury in patients with polytrauma: a consensus and clinical recommendations jointly developed by the World Society of Emergency Surgery (WSES) & the European Association of Neurosurgical Societies (EANS)

BACKGROUND

The early management of polytrauma patients with traumatic spinal cord injury (tSCI) is a major challenge. Sparse data is available to provide optimal care in this scenario and worldwide variability in clinical practice has been documented in recent studies.

METHODS

A multidisciplinary consensus panel of physicians selected for their established clinical and scientific expertise in the acute management of tSCI polytrauma patients with different specializations was established. The World Society of Emergency Surgery (WSES) and the European Association of Neurosurgical Societies (EANS) endorsed the consensus, and a modified Delphi approach was adopted.

RESULTS

A total of 17 statements were proposed and discussed. A consensus was reached generating 17 recommendations (16 strong and 1 weak).

CONCLUSIONS

This consensus provides practical recommendations to support a clinician's decision making in the management of tSCI polytrauma patients.

Pre-hospital ECPR in an Australian metropolitan setting: a single-arm feasibility assessment-The CPR, pre-hospital ECPR and early reperfusion (CHEER3) study

INTRODUCTION

Survival from refractory out of hospital cardiac arrest (OHCA) without timely return of spontaneous circulation (ROSC) utilising conventional advanced cardiac life support (ACLS) therapies is dismal. CHEER3 was a safety and feasibility study of pre-hospital deployed extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) for refractory OHCA in metropolitan Australia.

METHODS

This was a single jurisdiction, single-arm feasibility study. Physicians, with pre-existing ECMO expertise, responded to witnessed OHCA, age < 65 yrs, within 30 min driving-time, using an ECMO equipped rapid response vehicle. If pre-hospital ECPR was undertaken, patients were transported to hospital for investigations and therapies including emergent coronary catheterisation, and standard intensive care (ICU) therapy until either cardiac and neurological recovery or palliation occurred. Analyses were descriptive.

RESULTS

From February 2020 to May 2023, over 117 days, the team responded to 709 "potential cardiac arrest" emergency calls. 358 were confirmed OHCA. Time from emergency call to scene arrival was 27 min (15-37 min). 10 patients fulfilled the pre-defined inclusion criteria and all were successfully cannulated on scene. Time from emergency call to ECMO initiation was 50 min (35-62 min). Time from decision to ECMO support was 16 min (11-26 min). CPR duration was 46 min (32-62 min). All 10 patients were transferred to hospital for investigations and therapy. 4 patients (40%) survived to hospital discharge neurologically intact (CPC 1/2).

CONCLUSION

Pre-hospital ECPR was feasible, using an experienced ECMO team from a single-centre. Overall survival was promising in this highly selected group. Further prospective studies are now warranted.

Early Net Ultrafiltration during Continuous Renal Replacement Therapy: Impact of Admission Diagnosis and Association with Mortality

INTRODUCTION

Continuous renal replacement therapy (CRRT) is common in the intensive care unit (ICU) but a high net ultrafiltration rate (UFNET) calculated with daily data may increase mortality. We aimed to study early UFNET practice using minute-by-minute CRRT machine recordings and to assess its association with admission diagnosis and mortality.

METHODS

We studied CRRT treatments in three adult ICUs over 7 years. We calculated early UFNET rates minute-by-minute and categorized UFNET into tertiles of mean UFNET in the first 72 h and admission diagnosis. We applied Cox-proportional hazards modelling with censoring of patients who died within 72 h.

RESULTS

We studied 1,218 patients, 154,712 h, and 9,282,729 min of CRRT (5,702 circuits). Mean early UFNET was 1.52 (1.46-1.57) mL/kg/h. Early UFNET tertiles were similar to, but somewhat higher than, previously reported values at 0.00-1.20 mL/kg/h, 1.21-1.93 mL/kg/h, and >1.93 mL/kg/h. UFNET values were similar whether evaluated at 24 or 72 h or for the entire duration of CRRT. There was, however, significant variation in UFNET practice by admission diagnosis: higher in respiratory diseases (pneumonia p = 0.01, other p < 0.0001) and cardiovascular disease (p = 0.005) but lower in cardiothoracic surgery (p = 0.04), renal (p = 0.0003) and toxicology-associated diagnoses (p = 0.01). Higher UFNET was associated with an increased hazard of death, HR 1.24 (1.13-1.37), independent of admission diagnosis, weight, age, sex, presence of end-stage kidney disease, and severity of illness.

CONCLUSION

Early UFNET practice varies significantly by admission diagnosis. Higher early UFNET is independently associated with mortality. Impacts of UFNET on mortality may vary by admission diagnosis. Further work is required to elucidate the nature and mechanisms responsible for this association.

Sodium Bicarbonate for Metabolic Acidosis in the ICU: Results of a Pilot Randomized Double-Blind Clinical Trial

OBJECTIVES

To identify the best population, design of the intervention, and to assess between-group biochemical separation, in preparation for a future phase III trial.

DESIGN

Investigator-initiated, parallel-group, pilot randomized double-blind trial.

SETTING

Eight ICUs in Australia, New Zealand, and Japan, with participants recruited from April 2021 to August 2022.

PATIENTS

Thirty patients greater than or equal to 18 years, within 48 hours of admission to the ICU, receiving a vasopressor, and with metabolic acidosis (pH < 7.30, base excess [BE] < -4 mEq/L, and Pa co2 < 45 mm Hg).

INTERVENTIONS

Sodium bicarbonate or placebo (5% dextrose).

MEASUREMENTS AND MAIN RESULT

The primary feasibility aim was to assess eligibility, recruitment rate, protocol compliance, and acid-base group separation. The primary clinical outcome was the number of hours alive and free of vasopressors on day 7. The recruitment rate and the enrollment-to-screening ratio were 1.9 patients per month and 0.13 patients, respectively. Time until BE correction (median difference, -45.86 [95% CI, -63.11 to -28.61] hr; p < 0.001) and pH correction (median difference, -10.69 [95% CI, -19.16 to -2.22] hr; p = 0.020) were shorter in the sodium bicarbonate group, and mean bicarbonate levels in the first 24 hours were higher (median difference, 6.50 [95% CI, 4.18 to 8.82] mmol/L; p < 0.001). Seven days after randomization, patients in the sodium bicarbonate and placebo group had a median of 132.2 (85.6-139.1) and 97.1 (69.3-132.4) hours alive and free of vasopressor, respectively (median difference, 35.07 [95% CI, -9.14 to 79.28]; p = 0.131). Recurrence of metabolic acidosis in the first 7 days of follow-up was lower in the sodium bicarbonate group (3 [20.0%] vs. 15 [100.0%]; p < 0.001). No adverse events were reported.

CONCLUSIONS

The findings confirm the feasibility of a larger phase III sodium bicarbonate trial; eligibility criteria may require modification to facilitate recruitment.

Nutrition care processes across hospitalisation in critically ill patients with COVID-19 in Australia: A multicentre prospective observational study

BACKGROUND

The COVID-19 pandemic highlighted major challenges with usual nutrition care processes, leading to reports of malnutrition and nutrition-related issues in these patients.

OBJECTIVE

The objective of this study was to describe nutrition-related service delivery practices across hospitalisation in critically ill patients with COVID-19 admitted to Australian intensive care units (ICUs) in the initial pandemic phase.

METHODS

This was a multicentre (nine site) observational study in Australia, linked with a national registry of critically ill patients with COVID-19. Adult patients with COVID-19 who were discharged to an acute ward following ICU admission were included over a 12-month period. Data are presented as n (%), median (interquartile range [IQR]), and odds ratio (OR [95% confidence interval {CI}]).

RESULTS

A total of 103 patients were included. Oral nutrition was the most common mode of nutrition (93 [93%]). In the ICU, there were 53 (52%) patients seen by a dietitian (median 4 [2-8] occasions) and malnutrition screening occurred in 51 (50%) patients most commonly with the malnutrition screening tool (50 [98%]). The odds of receiving a higher malnutrition screening tool score increased by 36% for every screening in the ICU (1st to 4th, OR: 1.39 [95% CI: 1.05-1.77] p = 0.018) (indicating increasing risk of malnutrition). On the ward, 51 (50.5%) patients were seen by a dietitian (median time to consult: 44 [22.5-75] hours post ICU discharge). The odds of dietetic consult increased by 39% every week while on the ward (OR: 1.39 [1.03-1.89], p = 0.034). Patients who received mechanical ventilation (MV) were more likely to receive dietetic input than those who never received MV.

CONCLUSIONS

During the initial phases of the COVID-19 pandemic in Australia, approximately half of the patients included were seen by a dietitian. An increased number of malnutrition screens were associated with a higher risk score in the ICU and likelihood of dietetic consult increased if patients received MV and as length of ward stay increased.

Therapeutic Hypothermia for Refractory Hypoxemia on Venovenous Extracorporeal Membrane Oxygenation: An In Silico Study

Patients with respiratory failure may remain hypoxemic despite treatment with venovenous extracorporeal membrane oxygenation (VV-ECMO). Therapeutic hypothermia is a potential treatment for such hypoxia as it reduces cardiac output ( ) and oxygen consumption. We modified a previously published mathematical model of gas exchange to investigate the effects of hypothermia during VV-ECMO. Partial pressures were expressed as measured at 37°C (α-stat). The effect of hypothermia on gas exchange was examined in four clinical scenarios of hypoxemia on VV-ECMO, each with different physiological derangements. All scenarios had arterial partial pressure of oxygen (PaO 2 ) ≤ 46 mm Hg and arterial oxygen saturation of hemoglobin (SaO 2 ) ≤ 81%. Three had high with low extracorporeal blood flow to ratio ( ). The problem in the fourth scenario was recirculation, with normal . Cooling to 33°C increased SaO 2 to > 89% and PaO 2 to > 50 mm Hg in all scenarios. Mixed venous oxygen saturation of hemoglobin as % ( ) increased to > 70% and mixed venous partial pressure of oxygen in mm Hg ( ) increased to > 34 mm Hg in scenarios with low . In the scenario with high recirculation, and increased, but to < 50% and < 27 mm Hg, respectively. This in silico study predicted cooling to 33°C will improve oxygenation in refractory hypoxemia on VV-ECMO, but the improvement will be less when the problem is recirculation.

Protocol summary and statistical analysis plan for the low oxygen intervention for cardiac arrest injury limitation (LOGICAL) trial

Background

The effect of conservative vs. liberal oxygen therapy on outcomes of intensive care unit (ICU) patients with hypoxic ischaemic encephalopathy (HIE) is uncertain and will be evaluated in the Low Oxygen Intervention for Cardiac Arrest injury Limitation (LOGICAL) trial.

Objective

The objective of this study was to summarise the protocol and statistical analysis plans for the LOGICAL trial.

Design setting and participants

LOGICAL is a randomised clinical trial in adults in the ICU who are comatose with suspected HIE (i.e., those who have not obeyed commands following return of spontaneous circulation after a cardiac arrest where there is clinical concern about possible brain damage). The LOGICAL trial will include 1400 participants and is being conducted as a substudy of the Mega Randomised registry trial comparing conservative vs. liberal oxygenation targets in adults receiving unplanned invasive mechanical ventilation in the ICU (Mega-ROX).

Main outcome measures

The primary outcome is survival with favourable neurological function at 180 days after randomisation as measured with the Extended Glasgow Outcome Scale (GOS-E). A favourable neurological outcome will be defined as a GOS-E score of lower moderate disability or better (i.e. a GOS-E score of 5-8). Secondary outcomes include survival time, day 180 mortality, duration of invasive mechanical ventilation, ICU length of stay, hospital length of stay, the proportion of patients discharged home, quality of life assessed at day 180 using the EQ-5D-5L, and cognitive function assessed at day 180 using the Montreal Cognitive Assessment (MoCA-blind).

Conclusions

The LOGICAL trial will provide reliable data on the impact of conservative vs. liberal oxygen therapy in ICU patients with suspected HIE following resuscitation from a cardiac arrest. Prepublication of the LOGICAL protocol and statistical analysis plan prior to trial conclusion will reduce the potential for outcome-reporting or analysis bias.

Trial registration

Australian and New Zealand Clinical Trials Registry (ACTRN12621000518864).

Blend to Limit OxygEN in ECMO: A RanDomised ControllEd Registry (BLENDER) Trial: Study Protocol and Statistical Analysis Plan

Introduction

Critically ill patients supported with venoarterial extracorporeal membrane oxygenation (VA ECMO) are at risk of developing severe arterial hyperoxia, which has been associated with increased mortality. Lower saturation targets in this population may lead to deleterious episodes of severe hypoxia. This manuscript describes the protocol and statistical analysis plan for the Blend to Limit OxygEN in ECMO: A RanDomised ControllEd Registry (BLENDER) Trial.

Design

The BLENDER trial is a pragmatic, multicentre, registry-embedded, randomised clinical trial., registered at ClinicalTrials.gov (NCT03841084) and approved by The Alfred Hospital Ethics Committee project ID HREC/50486/Alfred-2019.

Participants and setting

Patients supported by VA ECMO for cardiogenic shock or cardiac arrest who are enrolled in the Australian national ECMO registry.

Intervention

The study compares a conservative oxygenation strategy (target arterial saturations 92-96%) with a liberal oxygenation strategy (target 97-100%).

Main Outcome Measures

The primary outcome is the number of intensive care unit (ICU)-free days for patients alive at day 60. Secondary outcomes include duration of mechanical ventilation, ICU and hospital mortality, the number of hypoxic episodes, neurocognitive outcomes, and health economic analyses. The 300-patient sample size enables us to detect a 3-day difference in ICU-free days at day 60, assuming a mean ICU-free days of 11 days, with a risk of type 1 error of 5% and power of 80%. Data will be analysed according to a predefined analysis plan. Findings will be disseminated in peer-reviewed publications.

Conclusions

This paper details the protocol and statistical analysis plan for the BLENDER trial, a registry-embedded, multicentre interventional trial comparing liberal and conservative oxygenation strategies in VA ECMO.

The relationship between nursing skill mix and severity of illness of patients admitted in Australian and New Zealand intensive care units

BACKGROUND

Critically ill patients in the intensive care environment require an appropriate nursing workforce to improve quality of care and patient outcomes. However, limited information exists as to the relationship between severity of illness and nursing skill mix in the intensive care.

OBJECTIVE

The aim of this study was to describe the variation in nursing skill mix across different hospital types and to determine if this was associated with severity of illness of critically ill patients admitted to adult intensive care units (ICUs) in Australia and New Zealand.

DESIGN & SETTING

A retrospective cohort study using the Australia and New Zealand Intensive Care Society Adult Patient Database (to provide information on patient demographics, severity of illness, and outcome) and the Critical Care Resources Registry (to provide information on annual nursing staffing levels and hospital type) from July 2014 to June 2020. Four hospital types (metropolitan, private, rural/regional, and tertiary) and three patient groups (elective surgical, emergency surgical, and medical) were examined.

MAIN OUTCOME MEASURE

The main outcome measure was the proportion of critical care specialist registered nurses (RNs) expressed as a percentage of the full-time equivalent (FTE) of total RNs working within each ICU each year, as reported annually to the Critical Care Resources Registry.

RESULTS

Data were examined for 184 ICUs in Australia and New Zealand. During the 6-year study period, 770 747 patients were admitted to these ICUs. Across Australia and New Zealand, the median percentage of registered nursing FTE with a critical care qualification for each ICU (n = 184) was 59.1% (interquartile range [IQR] = 48.9-71.6). The percentage FTE of critical care specialist RNs was highest in private [63.7% (IQR = 52.6-78.2)] and tertiary ICUs [58.1% (IQR = 51.2-70.2)], followed by metropolitan ICUs [56.0% (IQR = 44.5-68.9)] with the lowest in rural/regional hospitals [55.9% (IQR = 44.9-70.0)]. In ICUs with higher percentage FTE of critical care specialist RNs, patients had higher severity of illness, most notably in tertiary and private ICUs. This relationship was persistent across all hospital types when examining subgroups of emergency surgical and medical patients and in multivariable analysis after adjusting for the type of hospital and relative percentage of each diagnostic group.

CONCLUSIONS

In Australian and New Zealand ICUs, the highest acuity patients are cared for by nursing teams with the highest percentage FTE of critical care specialist RNs. The Australian and New Zealand healthcare system has a critical care nursing workforce which scales to meet the acuity of ICU patients across Australia and New Zealand.

Blood Pressure Management Goals in Critically Ill Aneurysmal Subarachnoid Hemorrhage Patients in Australia and New Zealand

INTRODUCTION

Blood pressure (BP) management is common in patients with aneurysmal subarachnoid hemorrhage (SAH) admitted to an intensive care unit. However, the practice patterns of BP management (timing, dose, and duration) have not been studied locally.

METHODS

This post hoc analysis explored BP management goals (defined as the setting of a minimum systolic BP target or application of induced hypertension) in patients enrolled into the PROMOTE-SAH study in eleven neurosurgical centers in Australia and New Zealand. The primary outcome was 'dead or disabled' (modified Rankin Score ≥4) at 6 months, with the hypothesis being that setting BP management goals would be associated with improved outcomes.

RESULTS

BP management goals were recorded in 266 of 357 (75%) patients, of which 149 were recorded as receiving induced hypertension for delayed cerebral ischemia (DCI) or vasospasm on 738 (19%) study days. In patients with a minimum systolic BP goal recorded (on 2067 d), the indication for the BP management goal was vasospasm or DCI on 651 (32%) days; no indication for BP management goals was documented on 1416 (69%) days. Crude analysis demonstrated an association between setting BP management goals and reduced death or disability (P=0.03), but this association was not significant after adjustment for the presence of DCI or vasospasm and clustered by the site.

CONCLUSIONS

BP management goals are commonly 'prescribed' to aSAH patients admitted to an intensive care unit in Australia and New Zealand, but BP management goal setting was not associated with improved outcomes in the adjusted analysis.

The Impact of Sedative Choice on Intracranial and Systemic Physiology in Moderate to Severe Traumatic Brain Injury: A Scoping Review

Although sedative use is near-ubiquitous in the acute management of moderate to severe traumatic brain injury (m-sTBI), the evidence base for these agents is undefined. This review summarizes the evidence for analgosedative agent use in the intensive care unit management of m-sTBI. Clinical studies of sedative and analgosedative agents currently utilized in adult m-sTBI management (propofol, ketamine, benzodiazepines, opioids, and alpha-2 agonists) were identified and assessed for relevance and methodological quality. The primary outcome was the effect of the analgosedative agent on intracranial pressure (ICP). Secondary outcomes included intracranial hemodynamic and metabolic parameters, systemic hemodynamic parameters, measures of therapeutic intensity, and clinical outcomes. Of 594 articles identified, 61 met methodological review criteria, and 40 were included in the qualitative summary; of these, 33 were prospective studies, 18 were randomized controlled trials, and 8 were blinded. There was consistent evidence for the efficacy of sedative agents in the management of m-sTBI and raised ICP, but the overall quality of the evidence was poor, consisting of small studies (median sample size, 23.5) of variable methodological quality. Propofol and midazolam achieve the goals of sedation without notable differences in efficacy or safety, although high-dose propofol may disrupt cerebral autoregulation. Dexmedetomidine and propofol/ dexmedetomidine combination may cause clinically significant hypotension. Dexmedetomidine was effective to achieve a target sedation score. De novo opioid boluses were associated with increased ICP and reduced cerebral perfusion pressure. Ketamine bolus and infusions were not associated with increased ICP and may reduce the incidence of cortical spreading depolarization events. In conclusion, there is a paucity of high-quality evidence to inform the optimal use of analgosedative agents in the management of m-sTBI, inferring significant scope for further research.

A Survey on Monitoring and Management of Cerebral Vasospasm and Delayed Cerebral Ischemia After Subarachnoid Hemorrhage: The Mantra Study

INTRODUCTION

Cerebral infarction from delayed cerebral ischemia (DCI) is a leading cause of poor neurological outcome after aneurysmal subarachnoid hemorrhage (aSAH). We performed an international clinical practice survey to identify monitoring and management strategies for cerebral vasospasm associated with DCI in aSAH patients requiring intensive care unit admission.

METHODS

The survey questionnaire was available on the European Society of Intensive Care Medicine (May 2021-June 2022) and Neurocritical Care Society (April - June 2022) websites following endorsement by these societies.

RESULTS

There were 292 respondents from 240 centers in 38 countries. In conscious aSAH patients or those able to tolerate an interruption of sedation, neurological examination was the most frequently used diagnostic modality to detect delayed neurological deficits related to DCI caused by cerebral vasospasm (278 respondents, 95.2%), while in unconscious patients transcranial Doppler/cerebral ultrasound was most frequently used modality (200, 68.5%). Computed tomography angiography was mostly used to confirm the presence of vasospasm as a cause of DCI. Nimodipine was administered for DCI prophylaxis by the majority of the respondents (257, 88%), mostly by an enteral route (206, 71.3%). If there was a significant reduction in arterial blood pressure after nimodipine administration, a vasopressor was added and nimodipine dosage unchanged (131, 45.6%) or reduced (122, 42.5%). Induced hypertension was used by 244 (85%) respondents as first-line management of DCI related to vasospasm; 168 (59.6%) respondents used an intra-arterial procedure as second-line therapy.

CONCLUSIONS

This survey demonstrated variability in monitoring and management strategies for DCI related to vasospasm after aSAH. These findings may be helpful in promoting educational programs and future research.

The Impact of Nursing Skill-mix on Adverse Events in Intensive Care: A Single Centre Cohort Study

BACKGROUND

The highly complex and technological environment of critical care manages the most critically unwell patients in the hospital system, as such there is a need for a highly trained nursing workforce. Intensive care is considered a high-risk area for errors and adverse events (AE) due to the severity of illness and number of procedures performed.

OBJECTIVE

To investigate if the percentage of Critical Care Registered Nurses (CCRN) within an Intensive Care Unit (ICU) is associated with an increased risk of patients experiencing an AE.

DESIGN & SETTING

We conducted a retrospective cohort study of patients admitted between January 2016 and December 2020 to a tertiary ICU in Australia. Descriptive statistics and multivariable logistic regression were used to investigate the relationship between the proportion of CCRNs each month and the occurrence of an AE defined as any one of a medication error, fall, pressure injury or unplanned removal of a central venous catheter or endotracheal tube per patient.

RESULTS

A total of 13,560 patients were included in the study, with 854 (6.3%) experiencing one AE. Patients with an AE were associated with higher illness severity and frailty scores. They were more commonly admitted after medical emergency team response calls and were less commonly elective ICU admissions. Those with an AE had longer ICU and in-hospital length of stay, and higher ICU and in-hospital mortality, on average. After adjusting for ICU LOS and acute severity of illness, being admitted during a month of higher critical care nursing skill-mix was associated with a statistically significant lower odds of having a subsequent AE (OR 0.966 [95% CI: 0.944-0.988], p 0.003).

CONCLUSION

An increasing percentage of CCRNs is independently associated with a lower risk-adjusted likelihood of an AE. Increasing the skill-mix of the ICU nursing staff may reduce the occurrence of AEs and lead to improved patient outcomes.

Continuous Renal Replacement Therapy during Extracorporeal Membrane Oxygenation: Circuit Haemodynamics and Circuit Failure

INTRODUCTION

Treatment with continuous renal replacement therapy (CRRT) is common during extracorporeal membrane oxygenation (ECMO). Such ECMO-CRRT has specific technical characteristics, which may affect circuit life. Accordingly, we studied CRRT haemodynamics and circuit life during ECMO.

METHODS

ECMO and non-ECMO-CRRT treatments in two adult intensive care units were compared using data collected over a 3-year period. A potential predictor of circuit survival identified in a 60% training data subset as a time-varying covariate within a Cox proportional hazard model was subsequently assessed in the complementary remaining data (40%).

RESULTS

Median [interquartile range] CRRT circuit life was greater when associated with ECMO (28.8 [14.0-65.2] vs. 20.2 [9.8-40.2] h, p &lt; 0.0001). Access, return, prefilter, and effluent pressures were also greater during ECMO. Higher ECMO flows were associated with higher access and return pressures. Classification and regression tree analysis identified an association between high access pressures and accelerated circuit failure, while both first access pressures ≥190 mm Hg (HR 1.58 [1.09-2.30]) and patient weight (HR 1.85 [1.15-2.97] third tertile vs. first tertile) were independently associated with circuit failure in a multivariable Cox model. Access dysfunction was associated with a stepwise increase in transfilter pressure, suggesting a potential mechanism of membrane injury.

CONCLUSION

CRRT circuits used in conjunction with ECMO have a longer circuit life than usual CRRT despite exposure to higher circuit pressures. Markedly elevated access pressures, however, may predict early CRRT circuit failure during ECMO, possibly via progressive membrane thrombosis as evidenced by increased transfilter pressure gradients.

Inter-hospital transfer and clinical outcomes for people with COVID-19 admitted to intensive care units in Australia: an observational cohort study

OBJECTIVES

To examine the association between inter-hospital transfer and in-hospital mortality among people with coronavirus disease 2019 (COVID-19) admitted to intensive care units (ICUs) in Australia.

DESIGN

Retrospective cohort study; analysis of data collected for the Short Period Incidence Study of Severe Acute Respiratory Illness (SPRINT-SARI) Australia study.

SETTING, PARTICIPANTS

People with COVID-19 admitted to 63 ICUs, 1 January 2020 - 1 April 2022.

MAIN OUTCOME MEASURES

Primary outcome: in-hospital mortality; secondary outcomes: ICU and hospital lengths of stay and frequency of selected complications.

RESULTS

Of 5207 people with records in the SPRINT-SARI Australia database at 1 April 2022, 328 (6.3%) had been transferred between hospitals, 305 (93%) during the third pandemic wave. Compared with patients not transferred, their median age was lower (53 years; interquartile range [IQR], 45-61 years v 60 years; IQR, 46-70 years), their median body mass index higher (32.5 [IQR, 27.2-39.0] kg/m² v 30.1 [IQR, 25.7-35.7] kg/m² ), and fewer had received a COVID-19 vaccine (22% v 44.9%); their median APACHE II scores were similar (14.0; IQR, 12.0-18.0 v 14.0; IQR, 10.0-19.0). Bacterial pneumonia (64.7% v 29.0%) and bacteraemia (27% v 8%) were more frequent in transferred patients, as was the need for more intensive ICU interventions, including invasive mechanical ventilation (71.2% v 38.1%) and extra-corporeal membrane oxygenation (26% v 1.7%). Crude ICU (19% v 14.9%) and in-hospital mortality (19% v 18.4%) were similar for patients who were or were not transferred; median lengths of ICU (20.0 [IQR, 11.2-40.3] days v 4.6 [IQR, 2.1-10.1] days) and hospital stay (29.7 [IQR, 18.1-49.6] days v 12.3 [IQR, 7.3-21.0] days) were longer for transferred patients. In the multivariable regression analysis, in-hospital mortality risk was lower for transferred patients (risk difference [RD], -5.0 percentage points; 95% confidence interval [CI] -10 to -0.03 percentage points), but not in the propensity score-adjusted analysis (RD, -3.4 [95% CI, -8.9 to 2.1] percentage points).

CONCLUSIONS

Among people with COVID-19 admitted to ICUs, patients transferred from another hospital required more intense interventions and remained in hospital longer, but were not at greater risk of dying in hospital than the patients who were not transferred.

Mental health and wellbeing of health and aged care workers in Australia, May 2021 - June 2022: a longitudinal cohort study

OBJECTIVES

To assess the mental health and wellbeing of health and aged care workers in Australia during the second and third years of the coronavirus disease 2019 (COVID-19) pandemic, overall and by occupation group.

DESIGN, SETTING, PARTICIPANTS

Longitudinal cohort study of health and aged care workers (ambulance, hospitals, primary care, residential aged care) in Victoria: May-July 2021 (survey 1), October-December 2021 (survey 2), and May-June 2022 (survey 3).

MAIN OUTCOME MEASURES

Proportions of respondents (adjusted for age, gender, socio-economic status) reporting moderate to severe symptoms of depression (Patient Health Questionnaire-9, PHQ-9), anxiety (Generalized Anxiety Disorder scale, GAD-7), or post-traumatic stress (Impact of Event Scale-6, IES-6), burnout (abbreviated Maslach Burnout Inventory, aMBI), or high optimism (10-point visual analogue scale); mean scores (adjusted for age, gender, socio-economic status) for wellbeing (Personal Wellbeing Index-Adult, PWI-A) and resilience (Connor Davidson Resilience Scale 2, CD-RISC-2).

RESULTS

A total of 1667 people responded to at least one survey (survey 1, 989; survey 2, 1153; survey 3, 993; response rate, 3.3%). Overall, 1211 survey responses were from women (72.6%); most respondents were hospital workers (1289, 77.3%) or ambulance staff (315, 18.9%). The adjusted proportions of respondents who reported moderate to severe symptoms of depression (survey 1, 16.4%; survey 2, 22.6%; survey 3, 19.2%), anxiety (survey 1, 8.8%; survey 2, 16.0%; survey 3, 11.0%), or post-traumatic stress (survey 1, 14.6%; survey 2, 35.1%; survey 3, 14.9%) were each largest for survey 2. The adjusted proportions of participants who reported moderate to severe symptoms of burnout were higher in surveys 2 and 3 than in survey 1, and the proportions who reported high optimism were smaller in surveys 2 and 3 than in survey 1. Adjusted mean scores for wellbeing and resilience were similar at surveys 2 and 3 and lower than at survey 1. The magnitude but not the patterns of change differed by occupation group.

CONCLUSION

Burnout was more frequently reported and mean wellbeing and resilience scores were lower in mid-2022 than in mid-2021 for Victorian health and aged care workers who participated in our study. Evidence-based mental health and wellbeing programs for workers in health care organisations are needed.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12621000533897 (observational study; retrospective).

Development of Traumatic Brain Injury Associated Intracranial Hypertension Prediction Algorithms: A Narrative Review

Traumatic intracranial hypertension (tIH) is a common and potentially lethal complication of moderate to severe traumatic brain injury (m-sTBI). It often develops with little warning and is managed reactively with the tiered application of intracranial pressure (ICP)-lowering interventions administered in response to an ICP rising above a set threshold. For over 45 years, a variety of research groups have worked toward the development of technology to allow for the preemptive management of tIH in the hope of improving patient outcomes. In 2022, the first operationalizable tIH prediction system became a reality. With such a system, ICP lowering interventions could be administered prior to the rise in ICP, thus protecting the patient from potentially damaging tIH episodes and limiting the overall ICP burden experienced. In this review, we discuss related approaches to ICP forecasting and IH prediction algorithms, which collectively provide the foundation for the successful development of an operational tIH prediction system. We also discuss operationalization and the statistical assessment of tIH algorithms. This review will be of relevance to clinicians and researchers interested in development of this technology as well as those with a general interest in the bedside application of machine learning (ML) technology.

Immediate Cooling and Early Decompression for the Treatment of Cervical Spinal Cord Injury: A Safety and Feasibility Study

Cervical spinal cord injury (SCI) usually results in severe, long-term disability. Early therapeutic hypothermia (33-34°C) has been used to improve outcomes in preclinical studies, but previous clinical studies have commenced cooling after arrival at hospital. The objective of the study is to determine the feasibility and safety of early therapeutic hypothermia initiated by paramedics and maintained for up to 24 hours in hospital in patients with SCI. This is a pilot clinical study. The study was undertaken at Ambulance Victoria and The Alfred Hospital, Victoria, Australia. A total of 17 consecutive patients with suspected acute traumatic cervical SCI were enrolled. Patients with suspected cervical SCI were administered a bolus (up to 20 mL/kg) intravenous (IV) cold (4°C) normal saline in the prehospital phase of care. After hospital admission and spinal imaging, further cooling used IV catheter temperature control or surface cooling. Major complications and long-term outcomes were compared with historical controls admitted to the same center before the study. A decrease in core temperature of 1.1°C was achieved during prehospital care and the target temperature was achieved in 6 hours with mechanical temperature management devices in the hospital. There were no major safety concerns. Patients with motor complete SCI who underwent early decompressive surgery had a favorable rate of partial spinal cord recovery compared with historical controls. Therapeutic hypothermia induced using bolus, large-volume, ice-cold saline prehospital and maintained for 24 hours using mechanical devices appears to be feasible and safe in patients with SCI. Larger trials need to be undertaken to determine whether prehospital cooling combined with early decompressive surgery improves outcomes in patients with complete cervical SCI. Australian and New Zealand Clinical Trials Registry (ACTRN12616001086459).

Assessment of a Non-Invasive Brain Pulse Monitor to Measure Intra-Cranial Pressure Following Acute Brain Injury

Background

Intracranial pressure (ICP) monitoring requires placing a hole in the skull through which an invasive pressure monitor is inserted into the brain. This approach has risks for the patient and is expensive. We have developed a non-invasive brain pulse monitor that uses red light to detect a photoplethysmographic (PPG) signal arising from the blood vessels on the brain's cortical surface. The brain PPG and the invasive ICP waveform share morphological features which may allow measurement of the intracranial pressure.

Methods

We enrolled critically ill patients with an acute brain injury with invasive ICP monitoring to assess the new monitor. A total of 24 simultaneous invasive ICP and brain pulse monitor PPG measurements were undertaken in 12 patients over a range of ICP levels.

Results

The waveform morphologies were similar for the invasive ICP and brain pulse monitor PPG approach. Both methods demonstrated a progressive increase in the amplitude of P2 relative to P1 with increasing ICP levels. An automated algorithm was developed to assess the PPG morphological features in relation to the ICP level. A correlation was demonstrated between the brain pulse waveform morphology and ICP levels, R²=0.66, P < 0.001.

Conclusion

The brain pulse monitor's PPG waveform demonstrated morphological features were similar to the invasive ICP waveform over a range of ICP levels, these features may provide a method to measure ICP levels.

Trial Registration

ACTRN12620000828921.

Early management of isolated severe traumatic brain injury patients in a hospital without neurosurgical capabilities: a consensus and clinical recommendations of the World Society of Emergency Surgery (WSES)

BACKGROUND

Severe traumatic brain-injured (TBI) patients should be primarily admitted to a hub trauma center (hospital with neurosurgical capabilities) to allow immediate delivery of appropriate care in a specialized environment. Sometimes, severe TBI patients are admitted to a spoke hospital (hospital without neurosurgical capabilities), and scarce data are available regarding the optimal management of severe isolated TBI patients who do not have immediate access to neurosurgical care.

METHODS

A multidisciplinary consensus panel composed of 41 physicians selected for their established clinical and scientific expertise in the acute management of TBI patients with different specializations (anesthesia/intensive care, neurocritical care, acute care surgery, neurosurgery and neuroradiology) was established. The consensus was endorsed by the World Society of Emergency Surgery, and a modified Delphi approach was adopted.

RESULTS

A total of 28 statements were proposed and discussed. Consensus was reached on 22 strong recommendations and 3 weak recommendations. In three cases, where consensus was not reached, no recommendation was provided.

CONCLUSIONS

This consensus provides practical recommendations to support clinician's decision making in the management of isolated severe TBI patients in centers without neurosurgical capabilities and during transfer to a hub center.

Early sedation in traumatic brain injury: a multicentre international observational study

Objectives: We aimed to investigate the use of sedation in patients with severe traumatic brain injury (TBI), focusing on the choice of sedative agent, dose, duration, and their association with clinical outcomes. Design: Multinational, multicentre, retrospective observational study. Settings: 14 trauma centres in Europe, Australia and the United Kingdom. Participants: A total of 262 adult patients with severe TBI and intracranial pressure monitoring. Main outcome measures: We described how sedative agents were used in this population. The primary outcome was 60-day mortality according to the use of different sedative agents. Secondary outcomes included intensive care unit and hospital length of stay, and the Extended Glasgow Outcome Scale at hospital discharge. Results: Propofol and midazolam were the most commonly used sedatives. Propofol was more common than midazolam as first line therapy (35.4% v 25.6% respectively). Patients treated with propofol had similar Acute Physiology and Chronic Health Evaluation (APACHE) II and International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) scores to patients treated with midazolam, but lower Injury Severity Score (ISS) (median, 26 [IQR, 22-38] v 34 [IQR, 26-44]; P = 0.001). The use of propofol was more common in heavier patients, and midazolam use was strongly associated with opioid co-administration (OR, 12.9; 95% CI, 3.47-47.95; P < 0.001). Sixty-day mortality and hospital mortality were predicted by a higher IMPACT score (P < 0.001) and a higher ISS (P < 0.001), but, after adjustment, were not related to the choice of sedative agent. Conclusions: Propofol was used more often than midazolam, and large doses were common for both sedatives. The first choice was highly variable, was affected by injury severity, and was not independently associated with 60-day mortality.

Circuit haemodynamics during non-citrate and regional citrate continuous renal replacement, and impact of blood flow on filter life

BACKGROUND

During continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA), blood flow (Qb) might affect vascular access dysfunction (AD) and, thereby, circuit life.

METHODS

Circuit life and circuit haemodynamics were studied in three intensive care units (ICUs) by analysing hemofilter device data (Prismaflex^®, Baxter, Chicago, IL). The three sites shared similar RCA protocols but differed in Qb (120-130 vs 150-200 mL/h). Non-RCA circuits were compared with RCA circuits in which the impact of Qb was also assessed.

RESULTS

About 3,981,906 min of circuit pressures were analysed in 2568 circuits in 567 patients. High-Qb RCA was associated with more extreme pressures, and greater AD (IRR 3.7 (1.93-7.08) as well as reduced filter life 21.1 (10.2-42.6) vs 27.0 (14.8-41.6) h). AD in high-Qb RCA circuits was associated with a 49% reduction in filter life, versus 24% reduction in low-Qb RCA, associated with a rise in the rate of increase in transfilter pressure.

CONCLUSIONS

High-Qb RCA-CRRT was associated with greater access dysfunction, earlier filter loss and increased haemodynamic impacts of access dysfunction, suggesting low-Qb RCA-CRRT may improve circuit mechanics, function and longevity.

A multicentre observational study of the use of antiseizure medication in patients with aneurysmal subarachnoid haemorrhage in the PROMOTE-SAH study

Our objective was to describe antiseizure medication (ASM) prescription patterns, and associations between ASM use and death and disability outcomes in patients with aneurysmal subarachnoid haemorrhage (aSAH) admitted to ICU. This was a multi-centre prospective observational study. The study took place in eleven ICUs across Australia and New Zealand. Data was collected from 1 April 2017 to 1 October 2018. Three hundred and fifty-seven adult patients with aSAH were enrolled. The primary outcome was to describe patterns of ASM prescription. The secondary outcome of interest was death or disability (modified Rankin Scale (mRS) score ≥ 4) at six months, and its association with ASM therapy, and relevant clinical subgroups. Forty percent of patients received an ASM and the most commonly used agent was levetiracetam. The median length of ASM administration was eight days (IQR 4.5-12.5). A number of patients with prehospital seizures did not receive ASM therapy (14/55, 2725%). There was a tendency towards ASM prescription with both higher radiological and clinical grade aSAH. There was no significant association between death or disability at six month (mRS ≥ 4) and ASM vs No ASM prescription. Testing for an interaction effect between ASM administration and WFNS grade suggested inferior outcomes with ASM use in lower aSAH grades (p = 0.04). In conclusion, the prescription of ASM for aSAH in Australia is variable across and within sites, with the majority of patients not receiving ASM chemoprophylaxis. We demonstrated no significant association between death or disability at six months and the use of ASM. There may be an association with poorer outcomes in patients with lower grade aSAH. This finding requires further exploration.

Temporal changes in the epidemiology of sepsis-related intensive care admissions from the emergency department in Australia and New Zealand

OBJECTIVES

The Australasian Resuscitation in Sepsis Evaluation (ARISE) study researched septic shock treatment within EDs. This study aims to evaluate whether: (i) conduct of the ARISE study was associated with changes in epidemiology and care for adults (≥18 years) admitted from EDs to ICUs with sepsis in Australia and New Zealand; and (ii) such changes differed among 45 ARISE trial hospitals compared with 120 non-trial hospitals.

METHODS

Retrospective study using interrupted time series analysis in three time periods; 'Pre-ARISE' (January 1997 to December 2007), 'During ARISE' (January 2008 to May 2014) and 'Post-ARISE' (June 2014 to December 2017) using data from the Australian and New Zealand Intensive Care Society Adult Patient Database.

RESULTS

Over 21 years there were 54 121 ICU admissions from the ED with sepsis; which increased from 8.1% to 16.4%; 54.6% male, median (interquartile range) age 66 (53-76) years. In the pre-ARISE period, pre-ICU ED length of stay (LOS) decreased in trial hospitals but increased in non-trial hospitals (P = 0.174). During the ARISE study, pre-ICU ED LOS declined more in trial hospitals (P = 0.039) as did the frequency of mechanical ventilation in the first 24 h (P = 0.003). However, ICU and hospital LOS, in-hospital mortality and risk of death declined similarly in both trial and non-trial hospitals.

CONCLUSIONS

Sepsis-related admissions increased from 8.1% to 16.4%. During the ARISE study, there was more rapid ICU admission and decreased early ventilation. However, these changes were not sustained nor associated with decreased risk of death or duration of hospitalisation.

Intensive care admissions following rapid response team reviews in patients with COVID-19 in Australia

Objectives: To evaluate the epidemiology of rapid response team (RRT) reviews that led to intensive care unit (ICU) admissions, and to evaluate the frequency of in-hospital cardiac arrests (IHCAs) among ICU patients with confirmed coronavirus disease 2019 (COVID-19) in Australia. Design: Multicentre, retrospective cohort study. Setting: 48 public and private ICUs in Australia. Participants: All adults (aged ≥ 16 years) with confirmed COVID-19 admitted to participating ICUs between 25 January and 31 October 2020, as part of SPRINT-SARI (Short PeRiod IncideNce sTudy of Severe Acute Respiratory Infection) Australia, which were linked with ICUs contributing to the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS APD). Main outcome measures and results: Of the 413 critically ill patients with COVID-19 who were analysed, 48.2% (199/413) were admitted from the ward and 30.5% (126/413) were admitted to the ICU following an RRT review. Patients admitted following an RRT review had higher Acute Physiology and Chronic Health Evaluation (APACHE) scores, fewer days from symptom onset to hospitalisation (median, 5.4 [interquartile range (IQR), 3.2-7.6] v 7.1 days [IQR, 4.1-9.8]; P < 0.001) and longer hospitalisations (median, 18 [IQR, 11-33] v 13 days [IQR, 7-24]; P < 0.001) compared with those not admitted via an RRT review. Admissions following RRT review comprised 60.3% (120/199) of all ward-based admissions. Overall, IHCA occurred in 1.9% (8/413) of ICU patients with COVID-19, and most IHCAs (6/8, 75%) occurred during ICU admission. There were no differences in IHCA rates or in ICU or hospital mortality rates based on whether a patient had a prior RRT review or not. Conclusions: This study found that RRT reviews were a common way for deteriorating ward patients with COVID-19 to be admitted to the ICU, and that IHCA was rare among ICU patients with COVID-19.

Mental Health Outcomes in Australian Healthcare and Aged-Care Workers during the Second Year of the COVID-19 Pandemic

Objective: the COVID-19 pandemic has incurred psychological risks for healthcare workers (HCWs). We established a Victorian HCW cohort (the Coronavirus in Victorian Healthcare and Aged-Care Workers (COVIC-HA) cohort study) to examine COVID-19 impacts on HCWs and assess organisational responses over time. Methods: mixed-methods cohort study, with baseline data collected via an online survey (7 May–18 July 2021) across four healthcare settings: ambulance, hospitals, primary care, and residential aged-care. Outcomes included self-reported symptoms of depression, anxiety, post-traumatic stress (PTS), wellbeing, burnout, and resilience, measured using validated tools. Work and home-related COVID-19 impacts and perceptions of workplace responses were also captured. Results: among 984 HCWs, symptoms of clinically significant depression, anxiety, and PTS were reported by 22.5%, 14.0%, and 20.4%, respectively, highest among paramedics and nurses. Emotional exhaustion reflecting moderate–severe burnout was reported by 65.1%. Concerns about contracting COVID-19 at work and transmitting COVID-19 were common, but 91.2% felt well-informed on workplace changes and 78.3% reported that support services were available. Conclusions: Australian HCWs employed during 2021 experienced adverse mental health outcomes, with prevalence differences observed according to occupation. Longitudinal evidence is needed to inform workplace strategies that support the physical and mental wellbeing of HCWs at organisational and state policy levels.

Clinical outcomes of Indigenous Australians and New Zealand Māori with metabolic acidosis and acidaemia

Objective: To assess the incidence and impact of metabolic acidosis in Indigenous and non-Indigenous patients Design: Retrospective study. Setting: Adult intensive care units (ICUs) from Australia and New Zealand. Participants: Patients aged 16 years or older admitted to an Australian or New Zealand ICU in one of 195 contributing ICUs between January 2019 and December 2020 who had metabolic acidosis, defined as pH < 7.30, base excess (BE) < -4 mEq/L and PaCO2 ≤ 45 mmHg. Main outcome measures: The primary outcome was the prevalence of metabolic acidosis. Secondary outcomes included ICU length of stay, hospital length of stay, receipt of renal replacement therapy (RRT), major adverse kidney events at 30 days (MAKE30), and hospital mortality. Results: Overall, 248 563 patients underwent analysis, with 11 537 (4.6%) in the Indigenous group and 237 026 (95.4%) in the non-Indigenous group. The prevalence of metabolic acidosis was higher in Indigenous patients (9.3% v 6.1%; P < 0.001). Indigenous patients with metabolic acidosis received RRT more often (28.2% v 22.0%; P < 0.001), but hospital mortality was similar between the groups (25.8% in Indigenous v 25.8% in non-Indigenous; P = 0.971). Conclusions: Critically ill Indigenous ICU patients are more likely to have a metabolic acidosis in the first 24 hours of their ICU admission, and more often received RRT during their ICU admission compared with non-Indigenous patients. However, hospital mortality was similar between the groups.

Six-month outcomes following venovenous ECMO for severe COVID-19 and viral pneumonitis: 2019-2020 Australian experience

Objective: To compare the characteristics, treatments and 6-month functional outcomes of patients with coronavirus disease 2019 (COVID-19) versus non-COVID-19 viral pneumonitis supported by venovenous extracorporeal membrane oxygenation (VV-ECMO). Design: Prospective, observational cohort study in seven intensive care units (ICUs) across Australia. Participants: Patients admitted to participating ICUs with laboratory-confirmed COVID-19 or viral pneumonitis requiring VV-ECMO. Results: From 30 March 2019 to 31 December 2020, 13 patients were initiated on VV-ECMO for COVID-19 and 23 were initiated for non-COVID-19 viral pneumonitis. Patients with COVID-19 were older and had a longer duration from intubation to ECMO initiation, but had similar illness severity and APACHE IV scores at the time of initiation. Overall disability, health-related quality of life, and mortality were similar, but ICU and hospital length of stay were significantly longer in patients with COVID-19. Conclusions: Six-month functional outcomes and mortality were similar between COVID-19 and viral pneumonitis patients treated with VV-ECMO. However, length of stay was longer in COVID-19 patients, which may have resource implications.

The Monitoring with Advanced Sensors, Transmission and E-Resuscitation in Traumatic Brain Injury (MASTER-TBI) collaborative: bringing data science to the ICU bedside

Background: With the adoption of multimodal neuromonitoring techniques, a large amount of high resolution neurophysiological data is generated during the treatment of patients with moderate to severe traumatic brain injury (m-sTBI) that is available for further analysis. The Monitoring with Advanced Sensors, Transmission and E-Resuscitation in Traumatic Brain Injury (MASTER-TBI) collaborative was formed in 2020 to facilitate analysis of these data. Objective: The MASTER-TBI collaborative curates m-sTBI patient data for the purposes of comparative effectiveness research, machine learning algorithm development, and neuropathophysiological phenomena analysis. Design, setting and participants: The MASTER-TBI collaborative is a multicentre longitudinal cohort study which utilises a novel hybrid cloud platform and other data science-informed techniques to collect and analyse data from patients with m-sTBI in whom both intracranial pressure monitoring and ICM+ (Cambridge Enterprise, Cambridge, UK) neuromonitoring software are utilised. MASTER-TBI enrols patients with m-sTBI from three participating Australian trauma intensive care units (ICUs). Main outcome measures: Captured outcome measures available for analysis include pathophysiological events (intracranial hypertension, cerebral perfusion pressure variations etc), surgical interventions, ICU and hospital length of stay, patient discharge status, and, where available, Glasgow Outcome Score-Extended (GOS-E) at 6 months. Results and conclusion: MASTER-TBI continues to develop data science-informed systems and techniques to maximise the use of captured high resolution m-sTBI patient neuromonitoring data. The highly innovative systems provide a world-class platform which aims to enhance the search for improved m-sTBI care and outcomes. This article provides an overview of the MASTER-TBI project's developed systems and techniques as well as a rationale for the approaches taken.

An initial Glasgow Coma Scale score of 8 or less does not define severe brain injury

The wide‐spread use of an initial ‘Glasgow Coma Scale (GCS) 8 or less’ to define and dichotomise ‘severe’ from ‘mild’ or ‘moderate’ traumatic brain injury (TBI) is an out‐dated research heuristic that has become an epidemiological convenience transfixing clinical care. Triaging based on GCS can delay the care of patients who have rapidly evolving injuries. Sole reliance on the initial GCS can therefore provide a false sense of security to caregivers and fail to provide timely care for patients presenting with GCS greater than 8. Nearly 50 years after the development of the GCS – and the resultant misplaced clinical and statistical definitions – TBI remains a heterogeneous entity, in which ‘best practice’ and ‘prognoses’ are poorly stratified by GCS alone. There is an urgent need for a paradigm shift towards more effective initial assessment of TBI.

A pilot, feasibility, randomised controlled trial of midodrine as adjunctive vasopressor for low-dose vasopressor-dependent hypotension in intensive care patients: The MAVERIC study

PURPOSE

To assess the feasibility and physiological efficacy of adjunctive midodrine in patients with vasopressor-dependent hypotension.

MATERIALS AND METHODS

This was a pilot, open label, randomised controlled trial. Patients were enrolled from two tertiary intensive care units on low dose intravenous vasopressor therapy for more than 24 h. We randomly assigned patients to receive either adjunctive midodrine (10 mg every 8 h) or usual care. The primary efficacy outcome was time to cessation of intravenous vasopressor therapy. Secondary outcomes included protocol compliance, ICU and hospital length of stay.

RESULTS

We screened 381 patients over 22-months and enrolled 62 (32 in midodrine group, 30 in usual care group). Median time to cessation of vasopressor infusion was 16.5 h for midodrine vs 19 h for usual care (p = 0.22). Time in ICU (50 [25.50, 74.00] hours for midodrine v 59 [38.50, 93.25] hours for usual care, p = 0.14) and hospital length of stay (9 days vs. 7.5 days, p = 0.92) were similar. Protocol compliance was 96.9%. One patient ceased midodrine early due to symptomatic bradycardia.

CONCLUSIONS

Adjunctive midodrine therapy was feasible with acceptable compliance, duration of therapy, and safety profile. However, at the chosen dose, there was no evidence of physiological or clinical efficacy.

Clinical characteristics, risk factors and outcomes in patients with severe COVID-19 registered in the International Severe Acute Respiratory and Emerging Infection Consortium WHO clinical characterisation protocol: a prospective, multinational, multicentre, observational study

Due to the large number of patients with severe coronavirus disease 2019 (COVID-19), many were treated outside the traditional walls of the intensive care unit (ICU), and in many cases, by personnel who were not trained in critical care. The clinical characteristics and the relative impact of caring for severe COVID-19 patients outside the ICU is unknown. This was a multinational, multicentre, prospective cohort study embedded in the International Severe Acute Respiratory and Emerging Infection Consortium World Health Organization COVID-19 platform. Severe COVID-19 patients were identified as those admitted to an ICU and/or those treated with one of the following treatments: invasive or noninvasive mechanical ventilation, high-flow nasal cannula, inotropes or vasopressors. A logistic generalised additive model was used to compare clinical outcomes among patients admitted or not to the ICU. A total of 40 440 patients from 43 countries and six continents were included in this analysis. Severe COVID-19 patients were frequently male (62.9%), older adults (median (interquartile range (IQR), 67 (55-78) years), and with at least one comorbidity (63.2%). The overall median (IQR) length of hospital stay was 10 (5-19) days and was longer in patients admitted to an ICU than in those who were cared for outside the ICU (12 (6-23) days versus 8 (4-15) days, p<0.0001). The 28-day fatality ratio was lower in ICU-admitted patients (30.7% (5797 out of 18 831) versus 39.0% (7532 out of 19 295), p<0.0001). Patients admitted to an ICU had a significantly lower probability of death than those who were not (adjusted OR 0.70, 95% CI 0.65-0.75; p<0.0001). Patients with severe COVID-19 admitted to an ICU had significantly lower 28-day fatality ratio than those cared for outside an ICU.

Nosocomial infections amongst critically ill COVID-19 patients in Australia

Purpose

To determine the frequency of nosocomial infections including hospital-acquired pneumonia (HAP) and bloodstream infection (BSI), amongst critically ill patients with COVID-19 infection in Australian ICUs and to evaluate associations with mortality and length of stay (LOS).

Methods

The effect of nosocomial infections on hospital mortality was evaluated using hierarchical logistic regression models to adjust for illness severity and mechanical ventilation.

Results

There were 490 patients admitted to 55 ICUs during the study period. Adjusted odds ratio (OR) for hospital mortality was 1.61 (95% confidence interval (CI) 0.61-4.27, p = 0.3) when considering BSI, and 1.76 (95% CI 0.73-4.21, p = 0.2) for HAP. The average adjusted ICU LOS was significantly longer for patients with BSI (geometric mean 9.0 days vs 6.3 days, p = 0.04) and HAP (geometric mean 13.9 days vs 6.0 days p<0.001).

Conclusion

Nosocomial infection rates amongst patients with COVID-19 were low and their development was associated with a significantly longer ICU LOS.

What Determines the Arterial Partial Pressure of Carbon Dioxide on Venovenous Extracorporeal Membrane Oxygenation?

Rapid reductions in PaCO2 during extracorporeal membrane oxygenation (ECMO) are associated with poor neurologic outcomes. Understanding what factors determine PaCO2 may allow a gradual reduction, potentially improving neurologic outcome. A simple and intuitive arithmetic expression was developed, to describe the interactions between the major factors determining PaCO2 during venovenous ECMO. This expression was tested using a wide range of input parameters from clinically feasible scenarios. The difference between PaCO2 predicted by the arithmetic equation and PaCO2 predicted by a more robust and complex in-silico mathematical model, was <10 mm Hg for more than 95% of the scenarios tested. With no CO2 in the sweep gas, PaCO2 is proportional to metabolic CO2 production and inversely proportional to the "total effective expired ventilation" (sum of alveolar ventilation and oxygenator ventilation). Extracorporeal blood flow has a small effect on PaCO2, which becomes more important at low blood flows and high recirculation fractions. With CO2 in the sweep gas, the increase in PaCO2 is proportional to the concentration of CO2 administered. PaCO2 also depends on the fraction of the total effective expired ventilation provided via the oxygenator. This relationship offers a simple intervention to control PaCO2 using titration of CO2 in the sweep gas.

ECMO (extra corporeal membrane oxygenation) in major trauma: A 10 year single centre experience

Aim To review the indications, complications and outcomes of extracorporeal membrane oxygenation (ECMO) in major trauma patients. Methods Single centre, retrospective, cohort study. Results Over a ten year period, from 13,420 major trauma patients, 11 were identified from our institutional trauma registry as having received ECMO. These patients were predominantly younger (mean 39 +/- 17 years), male (91%) and severely traumatised (median ISS 50, IQR 34 - 54). Veno-venous (VV) ECMO was used predominantly (n = 7, 64%), to treat hypoxic respiratory failure (mean PaO2/FiO2 ratio 69.7 +/- 38.6), secondary to traumatic lung injury. Veno-arterial (VA) ECMO was used less frequently, primarily to treat massive pulmonary embolism following trauma. Major bleeding complications occurred in four patients, however only one patient died from haemorrhage. Heparin free (2/11), delayed (3/11) or low dose heparin (2/11) therapy was frequently utilised. The median time from injury to ECMO initiation was 1 day (IQR 0.5 - 5.5) and median ECMO duration 9 days (IQR 6.5 - 10.5). ECMO was initiated <72 hours in 6 patients, with survival to discharge 67%, compared to 20% in those initiated >72 hours. Overall survival to discharge was 45%, and was higher with VV ECMO (64%), than other configurations (25%). Conclusion ECMO was rarely used in major trauma, the most common indication being severe hypoxaemic respiratory failure secondary to lung injury. In this severely injured cohort, overall survival was poor but better in VV compared to VA and better if initiated early (<72 hours), compared to late.

Intensive care doctors and nurses personal preferences for Intensive Care, as compared to the general population: a discrete choice experiment

Background

To test the hypothesis that Intensive Care Unit (ICU) doctors and nurses differ in their personal preferences for treatment from the general population, and whether doctors and nurses make different choices when thinking about themselves, as compared to when they are treating a patient.

Methods

Cross sectional, observational study conducted in 13 ICUs in Australia in 2017 using a discrete choice experiment survey. Respondents completed a series of choice sets, based on hypothetical situations which varied in the severity or likelihood of: death, cognitive impairment, need for prolonged treatment, need for assistance with care or requiring residential care.

Results

A total of 980 ICU staff (233 doctors and 747 nurses) participated in the study. ICU staff place the highest value on avoiding ending up in a dependent state. The ICU staff were more likely to choose to discontinue therapy when the prognosis was worse, compared with the general population. There was consensus between ICU staff personal views and the treatment pathway likely to be followed in 69% of the choices considered by nurses and 70% of those faced by doctors. In 27% (1614/5945 responses) of the nurses and 23% of the doctors (435/1870 responses), they felt that aggressive treatment would be continued for the hypothetical patient but they would not want that for themselves.

Conclusion

The likelihood of returning to independence (or not requiring care assistance) was reported as the most important factor for ICU staff (and the general population) in deciding whether to receive ongoing treatments. Goals of care discussions should focus on this, over likelihood of survival.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03712-4.

Use of a sensitive multisugar test for measuring segmental intestinal permeability in critically ill, mechanically ventilated adults: A pilot study

BACKGROUND

Increased intestinal permeability (IP) is associated with sepsis in the intensive care unit (ICU). This study aimed to pilot a sensitive multisugar test to measure IP in the nonfasted state.

METHODS

Critically ill, mechanically ventilated adults were recruited from 2 ICUs in Australia. Measurements were completed within 3 days of admission using a multisugar test measuring gastroduodenal (sucrose recovery), small-bowel (lactulose-rhamnose [L-R] and lactulose-mannitol [L-M] ratios), and whole-gut permeability (sucralose-erythritol ratio) in 24-hour urine samples. Urinary sugar concentrations were compared at baseline and after sugar ingestion, and IP sugar recoveries and ratios were explored in relation to known confounders, including renal function.

RESULTS

Twenty-one critically ill patients (12 males; median, 57 years) participated. Group median concentrations of all sugars were higher following sugar administration; however, sucrose and mannitol increases were not statistically significant. Within individual patients, sucrose and mannitol concentrations were higher in baseline than after sugar ingestion in 9 (43%) and 4 (19%) patients, respectively. Patients with impaired (n = 9) vs normal (n = 12) renal function had a higher L-R ratio (median, 0.130 vs 0.047; P = .003), lower rhamnose recovery (median, 15% vs 24%; P = .007), and no difference in lactulose recovery.

CONCLUSION

Small-bowel and whole-gut permeability measurements are possible to complete in the nonfasted state, whereas gastroduodenal permeability could not be measured reliably. For small-bowel IP measurements, the L-R ratio is preferred over the L-M ratio. Alterations in renal function may reduce the reliability of the multisugar IP test, warranting further exploration.