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.

Structured Weaning From the Impella Left Ventricular Micro-Axial Pump in Acute Myocardial Infarction With Cardiogenic Shock and Protected Percutaneous Coronary Intervention: Experience From a Non-Cardiac Surgical Centre

BACKGROUND

The Impella (Abiomed, Danvers, MA, USA) temporary percutaneous left ventricular assist device is increasingly used as mechanical circulatory support in patients with acute myocardial infarction-cardiogenic shock (AMICS) or those undergoing high-risk protected percutaneous coronary intervention (PCI). The optimal weaning regimen remains to be defined.

METHOD

We implemented a structured weaning protocol in a series of 10 consecutive patients receiving Impella support for protected PCI or AMICS treated with PCI in a high volume non-cardiac surgery centre. Weaning after revascularisation was titrated to native heart recovery using both haemodynamic and echocardiographic parameters.

RESULTS

Ten patients (eight male, two female; aged 43-70 years) received Impella support for AMICS (80%) or protected PCI (20%). Cardiogenic shock was of Society for Cardiac Angiography & Interventions grade C-E of severity in 80%, and median left ventricular end-diastolic pressure was 31 mmHg. Protocol implementation allowed successful weaning in eight of 10 patients with a median support time of 29 hours (range, 4-48 hours). Explantation was associated with an increase in heart rate (81 vs 88 bpm; p=0.005), but no significant change in Cardiac Index (2.9 vs 2.9 L/min/m2), mean arterial pressure (79 vs 82 mmHg), vasopressor requirement (10% vs 10%), or serum lactate (1.0 vs 1.0). Median durations of intensive care and hospital stay were 3 and 6 days, respectively. At 30 days, the mortality rate was 20%, with median left ventricular ejection fraction of 40%.

CONCLUSIONS

A structured and dynamic weaning protocol for patients with AMICS and protected PCI supported by the Impella device is feasible in a non-cardiac surgery centre. Larger studies are needed to assess generalisability of such a weaning protocol.

Clinician- and Patient-Identified Solutions to Reduce the Fragmentation of Post-ICU Care in Australia

BACKGROUND

Critical care survivors experience multiple care transitions, with no formal follow-up care pathway.

RESEARCH QUESTION

What are the potential solutions to improve the communication between treating teams and integration of care following an ICU admission, from the perspective of patients, their caregivers, intensivists, and general practitioners (GPs) from diverse socioeconomic areas?

STUDY DESIGN AND METHODS

This study included a qualitative design using semi-structured interviews with intensivists, GPs, and patients and caregivers. Framework analysis was used to analyze data and to identify solutions to improve the integration of care following hospital discharge. Patients were previously mechanically ventilated for > 24 h in the ICU and had access to a video-enabled device. Clinicians were recruited from hospital networks and a state-wide GP network.

RESULTS

Forty-six interviews with clinicians, patients, and caregivers were completed (15 intensivists, 8 GPs, 15 patients, and 8 caregivers). Three higher level feedback loops were identified that comprised 10 themes. Feedback loop 1 was an ICU and primary care collaboration. It included the following: (1) developing collaborative relationships between the ICU and primary care; (2) providing interprofessional education and resources to support primary care; and (3) improving role clarity for patient follow-up care. Feedback loop 2 was developing mechanisms for improved communication across the care continuum. It included: (4) timely, concise information-sharing with primary care on post-ICU recovery; (5) survivorship-focused information-sharing across the continuum of care; (6) empowering patients and caregivers in self-management; and (7) creation of a care coordinator role for survivors. Feedback loop 3 was learning from post-ICU outcomes to improve future care. It included: (8) developing comprehensive post-ICU care pathways; (9) enhancing support for patients following a hospital stay; and (10) integration of post-ICU outcomes within the ICU to improve clinician morale and understanding.

INTERPRETATION

Practical solutions to enhance the quality of survivorship for critical care survivors and their caregivers were identified. These themes are mapped to a novel conceptual model that includes key feedback loops for health system improvements and foci for future interventional trials to improve ICU survivorship outcomes.

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.

In-person peer support for critical care survivors: The ICU REcovery Solutions cO-Led through surVivor Engagement (ICURESOLVE) pilot randomised controlled trial

BACKGROUND

Peer support is a promising intervention to mitigate post-ICU disability, however there is a paucity of rigorously designed studies.

OBJECTIVES

The objective of this study was to establish feasibility of an in-person, co-designed, peer-support model.

METHODS

Prospective, randomised, adaptive, single-centre pilot trial with blinded outcome assessment, conducted at a university-affiliated hospital in Melbourne, Australia. Intensive care unit survivors (and their nominated caregiver, where survivor and caregiver are referred to as a dyad), >18 years of age, able to speak and understand English and participate in phone surveys, were eligible. Participants were randomised to the peer-support model (six sessions, fortnightly) or usual care (no follow-up or targeted information). Two sequential models were piloted: 1. Early (2-3 weeks post hospital discharge) 2. Later (4-6 weeks post hospital discharge). Primary outcome was feasibility of implementation measured by recruitment, intervention attendance, and outcome completion. Secondary outcomes included post-traumatic stress and social support.

RESULTS

Of the 231 eligible patients, 80 participants were recruited. In the early model we recruited 38 participants (28 patients, 10 carers; 18 singles, 10 dyads), with an average (standard deviation) age of 60 (18) years; 55 % were female. Twenty-two participants (58 %) were randomised to intervention. Participants in the early intervention model attended a median (interquartile range) of 0 (0-1) sessions (total 24 sessions), with 53% (n = 20) completing the main secondary outcome of interest (Impact of Event Scale) at the baseline and 37 % (n = 14) at the follow-up. For the later model we recruited 42 participants (32 patients, 10 carers; 22 singles, 10 dyads), with an average (standard deviation) age of 60.4 (15.4) years; 50 % were female. Twenty-one participants (50 %) were randomised to intervention. The later intervention model attended a median (interquartile range) of 1 (0-5) sessions (total: 44 sessions), with the main secondary outcome impact of events scale (IES-R) completed by 41 (98 %) participants at baseline and 29 (69 %) at follow-up.

CONCLUSIONS

In this pilot trial, a peer-support model that required in-person attendance delivered in a later posthospital phase of recovery appeared more feasible than an early model. Further research should investigate alternative modes of intervention delivery to improve feasibility (ACTRN12621000737831).

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.

Iron and erythropoietin to heal and recover after intensive care (ITHRIVE): A pilot randomised clinical trial

Objective

To determine the feasibility of a pivotal randomised clinical trial of intravenous (IV) iron and erythropoietin in adult survivors of critical illness with anaemia requiring treatment in the intensive care unit.

Design

An investigator-initiated, parallel group, placebo-controlled, randomised feasibility trial.

Setting

A tertiary intensive care unit (ICU) in Perth, Western Australia.

Participants

Adults with anaemia (haemoglobin <100 g/L), requiring ICU-level care for more than 48 h, and likely to be ready for ICU discharge within 24 h.

Interventions

A single dose of IV ferric carboxymaltose and Epoetin alfa (active group) or an equal volume of 0.9% saline (placebo group).

Main outcome measures

Study feasibility was considered met if the pilot achieved a recruitment rate of ≥2 participants per site per month, ≥90% of participants received their allocated study treatment, and≥ 90% of participants were followed up for the proposed pivotal trial primary outcome - days alive and at home to day 90 (DAH90).

Results

The 40-participant planned sample size included twenty in each group and was enrolled between 1/9/2021 and 2/3/2022. Participants spent a median of 3.4 days (interquartile range 2.8-5.1) in the ICU prior to enrolment and had a mean baseline haemoglobin of 83.7 g/L (standard deviation 6.7). The recruitment rate was 6.7 participants per month [95% confidence interval (CI) 4.8-9.0], DAH90 follow-up was 100% (95% CI 91.2%-100%), and 39 (97.5%, 95% CI 86.8%-99.9%) participants received the allocated study intervention. No serious adverse events were reported.

Conclusion

The iron and erythropoietin to heal and recover after intensive care (ITHRIVE) pilot demonstrated feasibility based on predefined participant recruitment, study drug administration, and follow-up thresholds.

Fragmentation of care between intensive and primary care settings and opportunities for improvement

PURPOSE

To explore the gaps in care provided across the transitions from the intensive care unit (ICU) to primary care, in order to improve post-ICU care.

METHODS

Semistructured interviews with three participant groups: intensivists, general practitioners (GPs) and patients and carers with framework analysis of textual data were used to investigate experiences of transitions of care post-ICU. Participants were purposively sampled for diversity. Eligible patients were adults, mechanically ventilated for >24 hours, with access to a video-enabled device. Exclusion criteria were non-English speaking and any cognitive/neurological limitation precluding interview participation.

RESULTS

A total of 46 interviews (15 patients, 8 caregivers, 15 intensivists and 8 GPs) were completed. Eight themes were identified, and categorised into three healthcare tiers. Tier 1, health system factors: (1) fragmentation of care; (2) communication gaps; (3) limited awareness and recognition of issues beyond the ICU; (4) lack of a specialised ICU follow-up pathway; Tier 2, clinician factors: (5) relationships among ICU, hospitals, GPs and patients and carers; (6) need for clinician role definition and clarity in ICU follow-up; Tier 3, patient and carer factors: (7) patient autonomy and self-actualisation and (8) the evolving caregiver role. A conceptual model was developed, highlighting bidirectional feedback loops between hospital and primary care.

CONCLUSION

This study identified gaps in care between ICU discharge and reintegration with primary care from the lived experience of patients, caregivers, intensivists and GPs. These data provide foci for future interventional research to improve the integration of care for this vulnerable and underserved cohort.

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.

Effect of Concomitant Cardiac Arrest on Outcomes in Patients With Acute Coronary Syndrome-Related Cardiogenic Shock

Patients with acute coronary syndrome (ACS)-related cardiogenic shock (CS) with or without concomitant CA may have disparate prognoses. We compared clinical characteristics and outcomes of patients with CS secondary to ACS with and without cardiac arrest (CA). Between 2014 and 2020, 1,573 patients with ACS-related CS with or without CA who underwent percutaneous coronary intervention enrolled in a multicenter Australian registry were analyzed. Primary outcome was 30-day major adverse cardiovascular and cerebrovascular events (MACCE) (composite of mortality, myocardial infarction, stent thrombosis, target vessel revascularization and stroke). Long-term mortality was obtained through linkage to the National Death Index. Compared with the no-CA group (n = 769, 49%), the CA group (n = 804, 51%) was younger (62 vs 69 years, p <0.001) and had fewer comorbidities. Patients with CA more frequently had ST-elevation myocardial infarction (92% vs 86%), occluded left anterior descending artery (43% vs 33%), and severe preprocedural renal impairment (49% vs 42%) (all p <0.001). CA increased risk of 30-day MACCE by 45% (odds ratio 1.45, 95% confidence interval 1.05 to 2.00, p = 0.024) after adjustment. CA group had higher 30-day MACCE (55% vs 42%, p <0.001) and mortality (52% vs 37%, p <0.001). Three-year survival was lower for CA compared with no-CA patients (43% vs 52%, p <0.001). In Cox regression, CS with CA was associated with a trend toward greater long-term mortality hazard (hazard ratio 1.19, 95% confidence interval 1.00 to 1.41, p = 0.055). In conclusion, concomitant CA among patients with ACS-related CS conferred a particularly heightened short-term risk with a diminishing legacy effect over time for mortality. CS survivors continue to exhibit high sustained long-term mortality hazard regardless of CA status.

Study protocol for TARGET protein: The effect of augmented administration of enteral protein to critically ill adults on clinical outcomes: A cluster randomised, cross-sectional, double cross-over, clinical trial

Background

It is unknown whether increasing dietary protein to 1.2-2.0 g/kg/day as recommended in international guidelines compared to current practice improves outcomes in intensive care unit (ICU) patients. The TARGET Protein trial will evaluate this.

Objective

To describe the study protocol for the TARGET Protein trial.

Design setting and participants

TARGET Protein is a cluster randomised, cross-sectional, double cross-over, pragmatic clinical trial undertaken in eight ICUs in Australia and New Zealand. Each ICU will be randomised to use one of two trial enteral formulae for three months before crossing over to the other formula, which is then repeated, with enrolment continuing at each ICU for 12 months. All patients aged ≥16 years in their index ICU admission commencing enteral nutrition will be eligible for inclusion. Eligible patients will receive the trial enteral formula to which their ICU is allocated. The two trial enteral formulae are isocaloric with a difference in protein dose: intervention 100g/1000 ml and comparator 63g/1000 ml. Staggered recruitment commenced in May 2022.

Main outcomes measures

The primary outcome is days free of the index hospital and alive at day 90. Secondary outcomes include days free of the index hospital at day 90 in survivors, alive at day 90, duration of invasive ventilation, ICU and hospital length of stay, incidence of tracheostomy insertion, renal replacement therapy, and discharge destination.

Conclusion

TARGET Protein aims to determine whether augmented enteral protein delivery reduces days free of the index hospital and alive at day 90.

Trial registration

Australian New Zealand Clinical Trials Registry (ACTRN12621001484831).

The effect of recombinant erythropoietin on long-term outcome after moderate-to-severe traumatic brain injury

PURPOSE

Recombinant erythropoietin (EPO) administered for traumatic brain injury (TBI) may increase short-term survival, but the long-term effect is unknown.

METHODS

We conducted a pre-planned long-term follow-up of patients in the multicentre erythropoietin in TBI trial (2010-2015). We invited survivors to follow-up and evaluated survival and functional outcome with the Glasgow Outcome Scale-Extended (GOSE) (categories 5-8 = good outcome), and secondly, with good outcome determined relative to baseline function (sliding scale). We used survival analysis to assess time to death and absolute risk differences (ARD) to assess favorable outcomes. We categorized TBI severity with the International Mission for Prognosis and Analysis of Clinical Trials in TBI model. Heterogeneity of treatment effects were assessed with interaction p-values based on the following a priori defined subgroups, the severity of TBI, and the presence of an intracranial mass lesion and multi-trauma in addition to TBI.

RESULTS

Of 603 patients in the original trial, 487 patients had survival data; 356 were included in the follow-up at a median of 6 years from injury. There was no difference between treatment groups for patient survival [EPO vs placebo hazard ratio (HR) (95% confidence interval (CI) 0.73 (0.47-1.14) p = 0.17]. Good outcome rates were 110/175 (63%) in the EPO group vs 100/181 (55%) in the placebo group (ARD 8%, 95% CI [Formula: see text] 3 to 18%, p = 0.14). When good outcome was determined relative to baseline risk, the EPO groups had better GOSE (sliding scale ARD 12%, 95% CI 2-22%, p = 0.02). When considering long-term patient survival, there was no evidence for heterogeneity of treatment effect (HTE) according to severity of TBI (p = 0.85), presence of an intracranial mass lesion (p = 0.48), or whether the patient had multi-trauma in addition to TBI (p = 0.08). Similarly, no evidence of treatment heterogeneity was seen for the effect of EPO on functional outcome.

CONCLUSION

EPO neither decreased overall long-term mortality nor improved functional outcome in moderate or severe TBI patients treated in the intensive care unit (ICU). The limited sample size makes it difficult to make final conclusions about the use of EPO in TBI.

Sex differences among patients presenting to hospital with out-of-hospital cardiac arrest and shockable rhythm

OBJECTIVE

Sex differences in patients presenting with out-of-hospital cardiac arrest (OHCA) and shockable rhythm might be associated with disparities in clinical outcomes.

METHODS

We conducted a retrospective cohort study and compared characteristics and short-term outcomes between male and female adult patients who presented with OHCA and shockable rhythm at two large metropolitan health services in Melbourne, Australia between the period of 2014-2018. Logistic regression was used to assess the effect of sex on clinical outcomes.

RESULTS

Of 212 patients, 166 (78%) were males and 46 (22%) were females. Both males and females presented with similar rates of ST-elevation myocardial infarction (44% vs 36%, P = 0.29), although males were more likely to have a history of coronary artery disease (32% vs 13%) and a final diagnosis of a cardiac cause for their OHCA (89% vs 72%), both P = 0.01. Rates of coronary angiography (81% vs 71%, P = 0.23) and percutaneous coronary intervention (51% vs 42%, P = 0.37) were comparable among males and females. No differences in rates of in-hospital mortality (38% vs 37%, P = 0.90) and 30-day major adverse cardiac and cerebrovascular events (composite of all-cause mortality, myocardial infarction, coronary revascularization and nonfatal stroke) (39% vs 41%, P = 0.79) were observed between males and females, respectively. Female sex was not associated with worse in-hospital mortality when adjusted for other variables (odds ratio 0.66, 95% confidence interval 0.28-1.60, P = 0.36).

CONCLUSION

Among patients presenting with OHCA and a shockable rhythm, baseline sex and sex differences were not associated with disparities in short-term outcomes in contemporary systems of care.

Evaluation of factors associated with selection for coronary angiography and in-hospital mortality among patients presenting with out-of-hospital cardiac arrest without ST-segment elevation

BACKGROUND

Clinical factors favouring coronary angiography (CA) selection and variables associated with in-hospital mortality among patients presenting with out-of-hospital cardiac arrest (OHCA) without ST-segment elevation (STE) remain unclear.

METHODS

We evaluated clinical characteristics associated with CA selection and in-hospital mortality in patients with OHCA, shockable rhythm and no STE.

RESULTS

Between 2014 and 2018, 118 patients with OHCA and shockable rhythm without STE (mean age 59; males 75%) were stratified by whether CA was performed. Of 86 (73%) patients undergoing CA, 30 (35%) received percutaneous coronary intervention (PCI). CA patients had shorter return of spontaneous circulation (ROSC) time (17 vs. 25 min) and were more frequently between 50 and 60 years (29% vs. 6.5%), with initial Glasgow Coma Scale (GCS) score >8 (24% vs. 6%) (all p < 0.05). In-hospital mortality was 33% (n = 39) for overall cohort (CA 27% vs. no-CA 50%, p = 0.02). Compared to late CA, early CA ( ≤ 2 h) was not associated with lower in-hospital mortality (32% vs. 34%, p = 0.82). Predictors of in-hospital mortality included longer defibrillation time (odds ratio 3.07, 95% confidence interval 1.44-6.53 per 5-min increase), lower pH (2.02, 1.33-3.09 per 0.1 decrease), hypoalbuminemia (2.02, 1.03-3.95 per 5 g/L decrease), and baseline renal dysfunction (1.33, 1.02-1.72 per 10 ml/min/1.73 m² decrease), while PCI to lesion (0.11, 0.01-0.79) and bystander defibrillation (0.06, 0.004-0.80) were protective factors (all p < 0.05).

CONCLUSIONS

Among patients with OHCA and shockable rhythm without STE, younger age, shorter time to ROSC and GCS >8 were associated with CA selection, while less effective resuscitation, greater burden of comorbidities and absence of treatable coronary lesion were key adverse prognostic predictors.

Quantum limits of position-sensitive photodiodes

The split photodiode and the lateral effect photodiode are two popular detectors for measuring beam displacement. For small displacements of a Gaussian beam, which is the case of interest here, they are often seen as equivalent and used interchangeably, giving a signal proportional to the displacement. We show theoretically and experimentally that in the limit of low technical noise, where the signal to noise ratio is dominated by the shot noise of the light, the lateral effect photodiode produces a better signal to noise ratio than the split photodiode, owing to its optimum spatial detector response. This quantum advantage can be practically exploited in spite of the intrinsic thermal noise of the lateral effect photodiode.

Violence in intensive care: a point prevalence study

Introduction: Violence in the intensive care unit (ICU) is poorly characterised and its incidence is largely extrapolated from studies in the emergency department. Policy requirements vary between jurisdictions and have not been formally evaluated. Methods: A multisite, single-time point observational study was conducted across Australasian ICUs which focused on the incidence of violence in the previous 24 hours, the characteristics of patients displaying violent behaviour, the perceived contributors, and the management strategies implemented. Unit policies were surveyed across a range of domains relevant to violence management. Results: Data were available for 627 patients admitted to 44 ICUs on one of 2 days in June 2019. Four per cent (25/627) displayed at least one episode of violent behaviour in the previous 24 hours. Violent behaviour was more likely in individuals after a greater length of stay in hospital (incidence, 2%, 4% and 7% for day 0-2, 3-7 and > 7 days respectively; P = 0.01) and in the ICU (2%, 4% and 9% for day 0-2, 3-7 and > 7 of ICU stay respectively; P < 0.01). The most common perceived contributors to violence were confusion (64%), physical illness (40%), and psychiatric illness (34%). Management with chemical sedation (72%) and physical restraint (28%) was commonly required. Clinicians assessed an additional 53 patients (53/627, 9%) as at risk of displaying violence in the next 24 hours. Of the 44 participating ICUs, 30 (68%) had a documented violence procedure. Conclusion: Violence in the ICU was common and frequently required intervention. In this study, one-third of ICUs did not have formal violence procedures, and in those with violence procedures, considerable variation was observed.

Determinants of Undertaking Coronary Angiography and Adverse Prognostic Predictors Among Patients Presenting With Out-of-Hospital Cardiac Arrest and a Shockable Rhythm

Characteristics of patients presenting with out-of-hospital cardiac arrest (OHCA) selected for coronary angiography (CA) and factors predicting in-hospital mortality remain unclear. We assessed clinical characteristics associated with undertaking CA in patients presenting with OHCA and shockable rhythm (CA group). Predictors of in-hospital mortality were evaluated with multivariable analysis. Of 1,552 patients presenting with cardiac arrest between 2014 and 2018 to 2 health services in Victoria, Australia, 213 patients with OHCA and shockable rhythm were stratified according to CA status. The CA group had shorter cardiopulmonary resuscitation duration (17 vs 25 minutes) and time to return of spontaneous circulation (17 vs 26 minutes) but higher proportion of ST-elevation on electrocardiogram (48% vs 24%) (all p <0.01). In-hospital mortality was 38% (n = 81) for the overall cohort, 32% (n = 54) in the CA group, and 61% (n = 27) in the no-CA group. Predictors of in-hospital mortality included non-selection for CA (odds ratio 4.5, 95% confidence interval 1.5 to 14), adrenaline support (3.9, 1.3 to 12), arrest at home (2.7, 1.1 to 6.6), longer time to defibrillation (2.5, 1.5 to 4.2 per 5-minute increase), lower blood pH (2.1, 1.4 to 3.2 per 0.1 decrease), lower albumin (2.0, 1.2 to 3.3 per 5 g/L decrease), higher Acute Physiology and Chronic Health Evaluation II score (1.7, 1.0 to 3.0 per 5-point increase), and advanced age (1.4, 1.0 to 2.0 per 10-year increase) (all p ≤0.05). In conclusion, non-selection for CA, concomitant cardiogenic shock requiring inotropic support, poor initial resuscitation (arrest at home, longer time to defibrillation and lower pH), greater burden of co-morbidities (higher Acute Physiology and Chronic Health Evaluation II score and lower albumin), and advanced age were key adverse prognostic indicators among patients with OHCA and shockable rhythm.

Percutaneous Coronary Intervention Volume and Cardiac Surgery Availability Effect on Acute Coronary Syndrome-Related Cardiogenic Shock

OBJECTIVES

This study sought to assess the association between cardiac surgery availability and percutaneous coronary intervention (PCI) volume with clinical outcomes of cardiogenic shock (CS) complicating acute coronary syndrome (ACS).

BACKGROUND

CS remains a grave complication of ACS with high mortality rates despite timely reperfusion and improved heart failure therapies.

METHODS

The study analyzed data from consecutive patients with CS complicating ACS who underwent PCI and were prospectively enrolled in the VCOR (Victorian Cardiac Outcomes Registry) from 26 hospitals in Victoria. We compared patients treated at cardiac surgical centers (CSCs) versus non-CSCs as well as the annual CS PCI volume (stratified into tiers of <10, 10-25, and >25 cases) for in-hospital major adverse cardiac and cerebrovascular events (MACCE) and long-term mortality.

RESULTS

Of 1,179 patients with CS, the mean age of patients was 65 years; males comprised 74%, and 22% had diabetes mellitus. Cardiac arrest occurred in 38% of patients, while 90% presented with ST-segment elevation myocardial infarction and 26% received intra-aortic balloon pump support. Overall, in-hospital and long-term mortality were 42% and 51%, respectively. There was no difference among patients treated non-CSCs compared with a CSCs for in-hospital MACCE and mortality (both P > 0.05). Similarly, there was no association between tiers of annual CS PCI volume with in-hospital MACCE and mortality (both P > 0.05).

CONCLUSIONS

Comparable short- and long-term mortality rates among patients with ACS complicated by CS treated by PCI irrespective of cardiac surgery availability and CS PCI volume support the emergent treatment of these gravely ill patients at their presenting PCI-capable hospital.

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.

A Post Hoc Analysis of Osmotherapy Use in the Erythropoietin in Traumatic Brain Injury Study-Associations With Acute Kidney Injury and Mortality

OBJECTIVES

Mannitol and hypertonic saline are used to treat raised intracerebral pressure in patients with traumatic brain injury, but their possible effects on kidney function and mortality are unknown.

DESIGN

A post hoc analysis of the erythropoietin trial in traumatic brain injury (ClinicalTrials.gov NCT00987454) including daily data on mannitol and hypertonic saline use.

SETTING

Twenty-nine university-affiliated teaching hospitals in seven countries.

PATIENTS

A total of 568 patients treated in the ICU for 48 hours without acute kidney injury of whom 43 (7%) received mannitol and 170 (29%) hypertonic saline.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We categorized acute kidney injury stage according to the Kidney Disease Improving Global Outcome classification and defined acute kidney injury as any Kidney Disease Improving Global Outcome stage-based changes from the admission creatinine. We tested associations between early (first 2 d) mannitol and hypertonic saline and time to acute kidney injury up to ICU discharge and death up to 180 days with Cox regression analysis. Subsequently, acute kidney injury developed more often in patients receiving mannitol (35% vs 10%; p < 0.001) and hypertonic saline (23% vs 10%; p < 0.001). On competing risk analysis including factors associated with acute kidney injury, mannitol (hazard ratio, 2.3; 95% CI, 1.2-4.3; p = 0.01), but not hypertonic saline (hazard ratio, 1.6; 95% CI, 0.9-2.8; p = 0.08), was independently associated with time to acute kidney injury. In a Cox model for predicting time to death, both the use of mannitol (hazard ratio, 2.1; 95% CI, 1.1-4.1; p = 0.03) and hypertonic saline (hazard ratio, 1.8; 95% CI, 1.02-3.2; p = 0.04) were associated with time to death.

CONCLUSIONS

In this post hoc analysis of a randomized controlled trial, the early use of mannitol, but not hypertonic saline, was independently associated with an increase in acute kidney injury. Our findings suggest the need to further evaluate the use and choice of osmotherapy in traumatic brain injury.

Aerosol generation related to respiratory interventions and the effectiveness of a personal ventilation hood

OBJECTIVE

To quantify aerosol generation from respiratory interventions and the effectiveness of their removal by a personal ventilation hood.

DESIGN AND SETTING

Determination of the aerosol particle generation (in a single, healthy volunteer in a clean room) associated with breathing, speaking, wet coughing, oxygen (O2) 15 L/min via face mask, O2 60 L/min via nasal prongs, bilevel non-invasive positive-pressure ventilation (BiPAP) and nebulisation with O2 10 L/min.

INTERVENTIONS

Aerosol generation was measured with two particle sizer and counter devices, focusing on aerosols 0.5-5 μm (human-generated aerosols), with and without the hood. An increase from baseline of less than 0.3 particles per mL was considered a low level of generation.

MAIN OUTCOME MEASURES

Comparisons of aerosol generation between different respiratory interventions. Effectiveness of aerosol reduction by a personal ventilation hood.

RESULTS

Results for the 0.5-5 μm aerosol range. Quiet breathing and talking demonstrated very low increase in aerosols (< 0.1 particles/mL). Aerosol generation was low for wet coughing (0.1 particles/mL), O2 15 L/min via face mask (0.18 particles/mL), and high flow nasal O2 60 L/min (0.24 particles/mL). Non-invasive ventilation generated moderate aerosols (29.7 particles/mL) and nebulisation very high aerosols (1086 particles/mL); the personal ventilation hood reduced the aerosol counts by 98% to 0.5 particles/mL and 8.9 particles/mL respectively.

CONCLUSIONS

In this human volunteer study, the administration of O2 15 L/min by face mask and 60 L/min nasal therapy did not increase aerosol generation beyond low levels. Non-invasive ventilation caused moderate aerosol generation and nebulisation therapy very high aerosol generation. The personal ventilation hood reduced the aerosol counts by at least 98%.

Aerosol generation related to respiratory interventions and the effectiveness of a personal ventilation hood

OBJECTIVE

To quantify aerosol generation from respiratory interventions and the effectiveness of their removal by a personal ventilation hood.

DESIGN AND SETTING

Determination of the aerosol particle generation (in a single, healthy volunteer in a clean room) associated with breathing, speaking, wet coughing, oxygen (O2) 15 L/min via face mask, O2 60 L/min via nasal prongs, bilevel non-invasive positive-pressure ventilation (BiPAP) and nebulisation with O2 10 L/min.

INTERVENTIONS

Aerosol generation was measured with two particle sizer and counter devices, focusing on aerosols 0.5-5 μm (human-generated aerosols), with and without the hood. An increase from baseline of less than 0.3 particles per mL was considered a low level of generation.

MAIN OUTCOME MEASURES

Comparisons of aerosol generation between different respiratory interventions. Effectiveness of aerosol reduction by a personal ventilation hood.

RESULTS

Results for the 0.5-5 μm aerosol range. Quiet breathing and talking demonstrated very low increase in aerosols (< 0.1 particles/mL). Aerosol generation was low for wet coughing (0.1 particles/mL), O2 15 L/min via face mask (0.18 particles/mL), and high flow nasal O2 60 L/min (0.24 particles/mL). Non-invasive ventilation generated moderate aerosols (29.7 particles/mL) and nebulisation very high aerosols (1086 particles/mL); the personal ventilation hood reduced the aerosol counts by 98% to 0.5 particles/mL and 8.9 particles/mL respectively.

CONCLUSIONS

In this human volunteer study, the administration of O2 15 L/min by face mask and 60 L/min nasal therapy did not increase aerosol generation beyond low levels. Non-invasive ventilation caused moderate aerosol generation and nebulisation therapy very high aerosol generation. The personal ventilation hood reduced the aerosol counts by at least 98%.

The Balance Hypothesis for the Avian Lumbosacral Organ and an Exploration of Its Morphological Variation

Birds (Aves) exhibit exceptional and diverse locomotor behaviors, including the exquisite ability to balance on two feet. How birds so precisely control their movements may be partly explained by a set of intriguing modifications in their lower spine. These modifications are collectively known as the lumbosacral organ (LSO) and are found in the fused lumbosacral vertebrae called the synsacrum. They include a set of transverse canal-like recesses in the synsacrum that align with lateral lobes of the spinal cord, as well as a dorsal groove in the spinal cord that houses an egg-shaped glycogen body. Based on compelling but primarily observational data, the most recent functional hypotheses for the LSO consider it to be a secondary balance organ, in which the transverse canals are analogous to the semicircular canals of the inner ear. If correct, this hypothesis would reshape our understanding of avian locomotion, yet the LSO has been largely overlooked in the recent literature. Here, we review the current evidence for this hypothesis and then explore a possible relationship between the LSO and balance-intensive locomotor ecologies. Our comparative morphological dataset consists of micro-computed tomography (μ-CT) scans of synsacra from ecologically diverse species. We find that birds that perch tend to have more prominent transverse canals, suggesting that the LSO is useful for balance-intensive behaviors. We then identify the crucial outstanding questions about LSO structure and function. The LSO may be a key innovation that allows independent but coordinated motion of the head and the body, and a full understanding of its function and evolution will require multiple interdisciplinary research efforts.

Systematic reviews and meta-analyses comparing mortality in restrictive and liberal haemoglobin thresholds for red cell transfusion: an overview of systematic reviews

BACKGROUND

There are no overviews of systematic reviews investigating haemoglobin thresholds for transfusion. This is important as the literature on transfusion thresholds has grown considerably in recent years. Our aim was to synthesise evidence from systematic reviews and meta-analyses of the effects of restrictive and liberal transfusion strategies on mortality.

METHODS

This was a systematic review of systematic reviews (overview). We searched MEDLINE, Embase, Web of Science Core Collection, PubMed, Google Scholar, and the Joanna Briggs Institute EBP Database, from 2008 to 2018. We included systematic reviews and meta-analyses of randomised controlled trials comparing mortality in patients assigned to red cell transfusion strategies based on haemoglobin thresholds. Two independent reviewers extracted data and assessed methodological quality. We assessed the methodological quality of included reviews using AMSTAR 2 and the quality of evidence pooled using an algorithm to assign GRADE levels.

RESULTS

We included 19 systematic reviews reporting 33 meta-analyses of mortality outcomes from 53 unique randomised controlled trials. Of the 33 meta-analyses, one was graded as high quality, 15 were moderate, and 17 were low. Of the meta-analyses presenting high- to moderate-quality evidence, 12 (75.0%) reported no statistically significant difference in mortality between restrictive and liberal transfusion groups and four (25.0%) reported significantly lower mortality for patients assigned to a restrictive transfusion strategy. We found few systematic reviews addressed clinical differences between included studies: variation was observed in haemoglobin threshold concentrations, the absolute between group difference in haemoglobin threshold concentration, time to randomisation (resulting in transfusions administered prior to randomisation), and transfusion dosing regimens.

CONCLUSIONS

Meta-analyses graded as high to moderate quality indicate that in most patient populations no difference in mortality exists between patients assigned to a restrictive or liberal transfusion strategy.

TRIAL REGISTRATION

PROSPERO CRD42019120503.

Vitamin C, Hydrocortisone and Thiamine in Patients with Septic Shock (VITAMINS) trial: study protocol and statistical analysis plan

BACKGROUND

Septic shock is associated with poor outcomes. Vitamin C (ascorbic acid) is a cellular antioxidant and has anti-inflammatory properties. Whether the combination therapy of vitamin C, thiamine and hydrocortisone reduces vasopressor dependency in septic shock is unclear.

OBJECTIVES

To describe the protocol and statistical analysis plan of a multicentre, open-label, prospective, phase 2 randomised clinical trial evaluating the effects of vitamin C, thiamine and hydrocortisone when compared with hydrocortisone monotherapy on the duration of vasopressor administration in critically ill patients with septic shock.

METHODS

VITAMINS is a multicentre cardiovascular efficacy trial in adult patients with septic shock. Randomisation occurs via a secure website with stratification by site, and allocation concealment is maintained throughout the trial. The primary outcome is the duration of time alive and free of vasopressor administration at Day 7. Secondary outcomes include feasibility endpoints and some patientcentred outcomes. All analyses will be conducted on an intention-to-treat basis.

CONCLUSION

The VITAMINS trial will determine whether combination therapy of vitamin C, thiamine and hydrocortisone when compared with hydrocortisone increases vasopressor-free hours in critically ill patients with septic shock. The conduct of this study will provide important information on the feasibility of studying this intervention in a phase 3 trial.

TRIAL REGISTRATION

ClinicalTrials.gov, identification No. NCT03333278.

Cost-Effectiveness of Erythropoietin in Traumatic Brain Injury: A Multinational Trial-Based Economic Analysis

The EPO-TBI multi-national randomized controlled trial found that erythropoietin (EPO), when compared to placebo, did not affect 6-month neurological outcome, but reduced illness severity-adjusted mortality in patients with traumatic brain injury (TBI), making the cost-effectiveness of EPO in TBI uncertain. The current study uses patient-level data from the EPO-TBI trial to evaluate the cost-effectiveness of EPO in patients with moderate or severe TBI from the healthcare payers' perspective. We addressed the issue of transferability in multi-national trials by estimating costs and effects for specific geographical regions of the study (Australia/New Zealand, Europe, and Saudi Arabia). Unadjusted mean quality-adjusted life-years (QALYs; 95% confidence interval [CI]) at 6 months were 0.027 (0.020-0.034; p < 0.001) higher in the EPO group, with an adjusted QALY increment of 0.014 (0.000-0.028; p = 0.04). Mean unadjusted costs (95% CI) were $US5668 (-9191 to -2144; p = 0.002) lower in the treatment group; controlling for baseline IMPACT-TBI score and regional heterogeneity reduced this difference to $2377 (-12,446 to 7693; p = 0.64). For a willingness-to-pay threshold of $US50,000 per QALY, 71.8% of replications were considered cost-effective. Therefore, we did not find evidence that EPO was significantly cost-effective in the treatment of moderate or severe TBI at 6-month follow-up.

Patient Blood Management: Recommendations From the 2018 Frankfurt Consensus Conference

IMPORTANCE

Blood transfusion is one of the most frequently used therapies worldwide and is associated with benefits, risks, and costs.

OBJECTIVE

To develop a set of evidence-based recommendations for patient blood management (PBM) and for research.

EVIDENCE REVIEW

The scientific committee developed 17 Population/Intervention/Comparison/Outcome (PICO) questions for red blood cell (RBC) transfusion in adult patients in 3 areas: preoperative anemia (3 questions), RBC transfusion thresholds (11 questions), and implementation of PBM programs (3 questions). These questions guided the literature search in 4 biomedical databases (MEDLINE, EMBASE, Cochrane Library, Transfusion Evidence Library), searched from inception to January 2018. Meta-analyses were conducted with the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) methodology and the Evidence-to-Decision framework by 3 panels including clinical and scientific experts, nurses, patient representatives, and methodologists, to develop clinical recommendations during a consensus conference in Frankfurt/Main, Germany, in April 2018.

FINDINGS

From 17 607 literature citations associated with the 17 PICO questions, 145 studies, including 63 randomized clinical trials with 23 143 patients and 82 observational studies with more than 4 million patients, were analyzed. For preoperative anemia, 4 clinical and 3 research recommendations were developed, including the strong recommendation to detect and manage anemia sufficiently early before major elective surgery. For RBC transfusion thresholds, 4 clinical and 6 research recommendations were developed, including 2 strong clinical recommendations for critically ill but clinically stable intensive care patients with or without septic shock (recommended threshold for RBC transfusion, hemoglobin concentration <7 g/dL) as well as for patients undergoing cardiac surgery (recommended threshold for RBC transfusion, hemoglobin concentration <7.5 g/dL). For implementation of PBM programs, 2 clinical and 3 research recommendations were developed, including recommendations to implement comprehensive PBM programs and to use electronic decision support systems (both conditional recommendations) to improve appropriate RBC utilization.

CONCLUSIONS AND RELEVANCE

The 2018 PBM International Consensus Conference defined the current status of the PBM evidence base for practice and research purposes and established 10 clinical recommendations and 12 research recommendations for preoperative anemia, RBC transfusion thresholds for adults, and implementation of PBM programs. The relative paucity of strong evidence to answer many of the PICO questions supports the need for additional research and an international consensus for accepted definitions and hemoglobin thresholds, as well as clinically meaningful end points for multicenter trials.

Reported practice of temperature adjustment (α-stat v pH-stat) for arterial blood gases measurement among investigators from two major cardiac arrest trials

BACKGROUND

Two major cardiac arrest trials are evaluating different strategies that may potentially mitigate neurological injury after cardiac arrest and are allowing co-enrolment. However, one trial will target hypothermia and the other will target mild hypercapnia, in which the carbon dioxide (CO₂) measurement may be influenced by the choice of temperature adjustment during arterial blood gases (ABGs) measurement. The trials have agreed to standardise assessment by the α-stat method.

OBJECTIVES

To describe the Targeted Therapeutic Mild Hypercapnia after Resuscitated Cardiac Arrest (TAME) and Targeted Hypothermia versus Targeted Normothermia after Out-of-hospital Cardiac Arrest (TTM2) site investigators' self-reported practice of ABG analysis and, in particular, their view of whether α-stat or pH-stat assessment of ABGs is considered optimal.

METHODS

We performed an online anonymous multichoice survey. Of the 136 site investigators emailed, 70 (51%) responded. Of these, 19 (27%) were participating in the TAME trial only, 22 (31%) were in TTm² only, and 29 (41%) were participating in both.

RESULTS

The majority of respondents identified α-stat (41/68, 60%) compared with pH-stat (27/68, 40%) as their usual approach to ABG analysis when targeting 33°C. In addition, the proportion and pattern of concern over hyperventilation was similarly reported as either "not concerned" or "neutral" when using an α-stat (46/69, 66%) or pH-stat (50/68, 73%) ABG analysis approach. Finally, for the purpose of a randomised controlled trial, most respondents either "strongly agreed", "agreed" or "neither agreed nor disagreed" to use the α-stat (59/69, 85%) or the pH-stat (61/70, 87%) approach.

CONCLUSION

Our survey findings support the acceptability of the decision to apply the α-stat approach across participating sites for both trials.

An audit of propofol administration in the intensive care unit: Infusion pump-recorded versus electronically documented amounts

BACKGROUND

Although propofol is widely used for sedation in intensive care units around Australia, evaluation of bedside nursing practices of the administration of propofol have been limited. We investigated whether there was a discrepancy between the amount of propofol delivered by the infusion pump and that recorded electronically and consequently patient exposure to avoidable harms.

AIMS

The aim of this research was to compare the total amount of propofol administered to intensive care patients via a programmable infusion pump with that documented in the electronic medical record (EMR). Secondary objectives were to ascertain the percentage of 1) patients exposed to a propofol dose greater than recommended and 2) daily energy requirements administered as propofol infusion.

METHODS

This was a prospective, observational study of total propofol delivered to 50 patients in a 14-bed metropolitan, Australian intensive care unit. Infusion pump data and entries from the EMR were collated.

RESULTS

Propofol sedation was administered for a median 18 (interquartile range: 14-47) hours with median total propofol 3025 mg (interquartile range: 1840-7755 mg) by pump and 3250 mg (interquartile range: 1915-6960 mg) by EMR, i.e. 1.9 (interquartile range: 1.3-2.3) mg/kg/hour by pump (correlation coefficient = 0.99). The total bolus propofol documented in the EMR was a median 330 mg (interquartile range: -838 to -124) less than the pump amount. Nineteen (38%) patients had no EMR-documented propofol boluses yet had received at least one bolus via the pump. In two of 50 (4%) patients, the pump propofol infusion dose was above the recommended maximum safe dose of 4 mg/kg/h.

CONCLUSION

In this cohort of patients, the bolus administration of propofol was frequently not documented, potentially placing some patients at risk of drug-related toxicity. Further research to develop and implement strategies to improve the documentation of propofol administration is indicated.

Erythropoietin in traumatic brain injury associated acute kidney injury: A randomized controlled trial

BACKGROUND

Acute kidney injury (AKI) in traumatic brain injury (TBI) is poorly understood and it is unknown if it can be attenuated using erythropoietin (EPO).

METHODS

Pre-planned analysis of patients included in the EPO-TBI (ClinicalTrials.gov NCT00987454) trial who were randomized to weekly EPO (40 000 units) or placebo (0.9% sodium chloride) subcutaneously up to three doses or until intensive care unit (ICU) discharge. Creatinine levels and urinary output (up to 7 days) were categorized according to the Kidney Disease Improving Global Outcome (KDIGO) classification. Severity of TBI was categorized with the International Mission for Prognosis and Analysis of Clinical Trials in TBI.

RESULTS

Of 3348 screened patients, 606 were randomized and 603 were analyzed. Of these, 82 (14%) patients developed AKI according to KDIGO (60 [10%] with KDIGO 1, 11 [2%] patients with KDIGO 2, and 11 [2%] patients with KDIGO 3). Male gender (hazard ratio [HR] 4.0 95% confidence interval [CI] 1.4-11.2, P = 0.008) and severity of TBI (HR 1.3 95% CI 1.1-1.4, P < 0.001 for each 10% increase in risk of poor 6 month outcome) predicted time to AKI. KDIGO stage 1 (HR 8.8 95% CI 4.5-17, P < 0.001), KDIGO stage 2 (HR 13.2 95% CI 3.9-45.2, P < 0.001) and KDIGO stage 3 (HR 11.7 95% CI 3.5-39.7, P < 0.005) predicted time to mortality. EPO did not influence time to AKI (HR 1.08 95% CI 0.7-1.67, P = 0.73) or creatinine levels during ICU stay (P = 0.09).

CONCLUSIONS

Acute kidney injury is more common in male patients and those with severe compared to moderate TBI and appears associated with worse outcome. EPO does not prevent AKI after TBI.

Erythropoietin in Critical Illness and Trauma

Erythropoietin (EPO) is a 34kD pleiotropic cytokine that was first identified as being essential for red blood cell (RBC) production. It is now recognized however that EPO is produced by many tissues. It plays a key role in the modulation of the response to injury, inflammation, and tissue hypoxia via the inhibition of apoptosis. Large clinical trials in the critically ill failed to demonstrate a role for EPO as an RBC transfusion sparing agent; however, improved clinical outcomes, attributable to EPO role in tissue protection are observed in critically ill trauma patients. Further research to confirm or refute these observations is required.

Commercial Low-citrate Anticoagulation Haemofiltration in High Risk Patients with Frequent Filter Clotting

This study assessed the safety and efficacy of a commercial low-citrate concentration-based pre-filter replacement fluid during continuous veno-venous haemofiltration (CVVH) in patients with frequent filter clotting and high risk of bleeding. We used a commercial low-citrate fluid as pre-dilution replacement fluid during CVVH (citrate: 11 mmol/l (33 meq/l), sodium: 140 mmol/l, chloride: 108 mmol/l and potassium: 1 mmol/l). A calcium and magnesium infusion was delivered separately by central line for the maintenance of serum ionized calcium (Cai) and total magnesium (Mg). In this prospective observational study, 30 patients, 124 filters and 1,515 treatment-hours were observed. Median filter life of citrate CVVH was 9.5 hours. Filter life in the 48 hours prior to citrate CVVH was also observed. In the patients on prior non-anticoagulant CVVH (n=14) filter life increased significantly with citrate (9.5 hours vs 5 hours; P<0.0001). In patients on prior heparin CVVH (n=15), filter life was similar with citrate (10 hours vs 8 hours; P=0.68). However, in patients with prior early/frequent filter clotting despite heparin (n=11) filter life increased significantly (10 hours vs 7 hours; P=0.038). Of 411 serum Cai measurements, none showed a Cai<0.85 mmol/l and, of 84 observations, none showed a serum Mg<0.6mmol/l. One patient with sepsis and shock needed to cease citrate CVVH because of progressive ionized hypocalcaemia and increasing anion gap. No other adverse effects were observed. In selected patients, CVVH with a commercial low-citrate concentration solution as pre-filter replacement fluid and a simultaneous calcium and magnesium infusion protocol appears generally safe. Filter life was acceptable and superior to that achieved with previous treatment.

Propofol Infusion Syndrome— Report of an Adult Fatality

This report describes a fatal case of the propofol infusion syndrome in an adult patient being sedated for a closed head injury using high doses of propofol. The features of circulatory collapse, metabolic acidosis, mild rhabdomyolysis and renal impairment are consistent with the syndrome and not readily attributable to alternative aetiologies. Potential mechanisms for the syndrome may relate to antagonism of beta-receptors, impaired myocardial oxygen utilization and a specific disruption to fatty-acid oxidation.

This is the first published Australian case of the propofol infusion syndrome in an adult and should serve as an additional case report to the existing literature highlighting this potentially fatal syndrome in adults.

Intensive care implications of epidemic thunderstorm asthma

OBJECTIVE

To investigate the environmental precipitants, treatment and outcome of critically ill patients affected by the largest and most lethal reported epidemic of thunderstorm asthma.

DESIGN, SETTING AND PARTICIPANTS

Retrospective multicentre observational study. Meteorological, airborne particulate and pollen data, and a case series of 35 patients admitted to 15 intensive care units (ICUs) due to the thunderstorm asthma event of 21-22 November 2016, in Victoria, Australia, were analysed and compared with 1062 total ICU-admitted Australian patients with asthma in 2016.

MAIN OUTCOME MEASURES

Characteristics and outcomes of total ICU versus patients with thunderstorm asthma, the association between airborne particulate counts and storm arrival, and ICU resource utilisation.

RESULTS

All 35 patients had an asthma diagnosis; 13 (37%) had a cardiac or respiratory arrest, five (14%) died. Compared with total Australian ICU-admitted patients with asthma in 2016, patients with thunderstorm asthma had a higher mortality (15% v 1.3%, P < 0.001), were more likely to be male (63% v 34%, P < 0.001), to be mechanically ventilated, and had shorter ICU length of stay in survivors (median, 31.8 hours [interquartile range (IQR), 14.8-43.6 hours] v 40.7 hours [IQR, 22.3-75.1 hours]; P = 0.025). Patients with cardiac arrest were more likely to be born in Asian or subcontinental countries (5/10 [50%] v 4/25 [16%]; relative risk, 3.13; 95% CI, 1.05-9.31). A temporal link was demonstrated between airborne particulate counts and arrival of the storm. The event used 15% of the public ICU beds in the region.

CONCLUSION

Arrival of a triggering storm is associated with an increase in respirable airborne particles. Affected critically ill patients are young, have a high mortality, a short duration of bronchospasm, and a prior diagnosis of asthma is common.

Hepcidin predicts response to IV iron therapy in patients admitted to the intensive care unit: a nested cohort study

Background

Both anaemia and red blood cell (RBC) transfusion are common and associated with adverse outcomes in patients admitted to the intensive care unit (ICU). The aim of this study was to determine whether serum hepcidin concentration, measured early after ICU admission in patients with anaemia, could identify a group in whom intravenous (IV) iron therapy decreased the subsequent RBC transfusion requirement.

Methods

We conducted a prospective observational study nested within a multicenter randomized controlled trial (RCT) of IV iron versus placebo. The study was conducted in the ICUs of four tertiary hospitals in Perth, Western Australia. Critically ill patients with haemoglobin (Hb) of < 100 g/L and within 48 h of admission to the ICU were eligible for participation after enrolment in the IRONMAN RCT. The response to IV iron therapy compared with placebo was assessed according to tertile of hepcidin concentration.

Results

Hepcidin concentration was measured within 48 h of ICU admission in 133 patients. For patients in the lower two tertiles of hepcidin concentration (< 53.0 μg), IV iron therapy compared with placebo was associated with a significant decrease in RBC transfusion requirement [risk ratio 0.48 (95% CI 0.26–0.85), p = 0.013].

Conclusions

In critically ill patients with anaemia admitted to an ICU, baseline hepcidin concentration predicts RBC transfusion requirement and is able to identify a group of patients in whom IV iron compared with placebo is associated with a significant decrease in RBC transfusion requirement.

Trial registration

Australian New Zealand Clinical Trials Registry: ANZCTRN12612001249 Registered 26/11/2012

Electronic supplementary material

The online version of this article (10.1186/s40560-018-0328-2) contains supplementary material, which is available to authorized users.