Mild Hypercapnia or Normocapnia after Out-of-Hospital Cardiac Arrest

BACKGROUND

Guidelines recommend normocapnia for adults with coma who are resuscitated after out-of-hospital cardiac arrest. However, mild hypercapnia increases cerebral blood flow and may improve neurologic outcomes.

METHODS

We randomly assigned adults with coma who had been resuscitated after out-of-hospital cardiac arrest of presumed cardiac or unknown cause and admitted to the intensive care unit (ICU) in a 1:1 ratio to either 24 hours of mild hypercapnia (target partial pressure of arterial carbon dioxide [Paco₂], 50 to 55 mm Hg) or normocapnia (target Paco₂, 35 to 45 mm Hg). The primary outcome was a favorable neurologic outcome, defined as a score of 5 (indicating lower moderate disability) or higher, as assessed with the use of the Glasgow Outcome Scale-Extended (range, 1 [death] to 8, with higher scores indicating better neurologic outcome) at 6 months. Secondary outcomes included death within 6 months.

RESULTS

A total of 1700 patients from 63 ICUs in 17 countries were recruited, with 847 patients assigned to targeted mild hypercapnia and 853 to targeted normocapnia. A favorable neurologic outcome at 6 months occurred in 332 of 764 patients (43.5%) in the mild hypercapnia group and in 350 of 784 (44.6%) in the normocapnia group (relative risk, 0.98; 95% confidence interval [CI], 0.87 to 1.11; P = 0.76). Death within 6 months after randomization occurred in 393 of 816 patients (48.2%) in the mild hypercapnia group and in 382 of 832 (45.9%) in the normocapnia group (relative risk, 1.05; 95% CI, 0.94 to 1.16). The incidence of adverse events did not differ significantly between groups.

CONCLUSIONS

In patients with coma who were resuscitated after out-of-hospital cardiac arrest, targeted mild hypercapnia did not lead to better neurologic outcomes at 6 months than targeted normocapnia. (Funded by the National Health and Medical Research Council of Australia and others; TAME ClinicalTrials.gov number, NCT03114033.).

Twelve-month mortality outcomes for Indigenous and non-Indigenous people admitted to intensive care units in Australia: a registry-based data linkage study

OBJECTIVE

To compare longer term (12-month) mortality outcomes for Indigenous and non-Indigenous people admitted to intensive care units (ICUs) in Australia.

DESIGN, SETTING, PARTICIPANTS

Retrospective registry-based data linkage cohort study; analysis of all admissions of adults (16 years or older) to Australian ICUs, 1 January 2017 - 31 December 2019, as recorded in the Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD), linked using the SLK-581 key to National Death Index data.

MAIN OUTCOME MEASURES

Unadjusted and adjusted mortality risk, censored at twelve months from the start of index ICU admission. Secondary outcomes were unadjusted and adjusted mortality twelve months from admission to the ICU.

RESULTS

The APD recorded 330 712 eligible ICU admissions during 2017-2019 (65% of all ICU admissions registered), of which 11 322 were of Indigenous people (3.4%). Median age at admission was lower for Indigenous patients (51.2 [IQR, 36.7-63.6] years) than for non-Indigenous patients (66.5 [IQR, 52.7-76.1] years). Unadjusted mortality risk was similar for Indigenous and non-Indigenous patients (hazard ratio, 1.01; 95% CI, 0.97-1.06), but was higher for Indigenous patients after adjusting for age, admission diagnosis, illness severity, hospital type, jurisdiction, remoteness and socio-economic status (adjusted hazard ratio, 1.20; 95% CI, 1.14-1.27). Twelve-month mortality was higher for Indigenous than non-Indigenous patients (adjusted odds ratio, 1.24; 95% CI, 1.16-1.33).

CONCLUSIONS

Twelve-month mortality outcomes are poorer for people admitted to ICUs in Australia than for the general population. Further, after adjusting for age and other factors, survival outcomes are poorer for Indigenous than non-Indigenous people admitted to ICUs. Critical illness may therefore contribute to shorter life expectancy among Indigenous Australians.

Sex Differences in Mortality of ICU Patients According to Diagnosis-related Sex Balance

Rationale: Women have worse outcomes than men in several conditions more common in men, including cardiac surgery and burns. Objectives: To describe the relationship between sex balance within each diagnostic group of ICU admissions, defined as the percentage of patients who were women, and hospital mortality of women compared with men with that same diagnosis. Methods: We studied ICU patients in the Australian and New Zealand Intensive Care Society's Adult Patient Database (2011-2020). We performed mixed effects logistic regression for hospital mortality adjusted for sex, illness severity, ICU lead time, admission year, and hospital site. We compared sex balance with the adjusted hospital mortality of women compared with men for each diagnosis using weighted linear regression. Measurements and Main Results: There were 1,450,782 admissions (42.1% women), with no difference in the adjusted hospital mortality of women compared with men overall (odds ratio, 0.99; 99% confidence interval [CI], 0.97 to 1). As the percentage of women within each diagnosis increased, the adjusted mortality of women compared with men with that same diagnosis decreased (regression coefficient, -0.015; 99% CI; -0.020 to -0.011; P < 0.001), and the illness severity of women compared with men at ICU admission decreased (regression coefficient, -0.0026; 99% CI, -0.0035 to -0.0018; P < 0.001). Conclusions: Sex balance in diagnostic groups was inversely associated with both the adjusted mortality and illness severity of women compared with men. In diagnoses with relatively few women, women were more likely than men to die. In diagnoses with fewer men, men were more likely than women to die.

Incidence of death or disability at 6 months after extracorporeal membrane oxygenation in Australia: a prospective, multicentre, registry-embedded cohort study

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is an invasive procedure used to support critically ill patients with the most severe forms of cardiac or respiratory failure in the short term, but long-term effects on incidence of death and disability are unknown. We aimed to assess incidence of death or disability associated with ECMO up to 6 months (180 days) after treatment.

METHODS

This prospective, multicentre, registry-embedded cohort study was done at 23 hospitals in Australia from Feb 15, 2019, to Dec 31, 2020. The EXCEL registry included all adults (≥18 years) in Australia who were admitted to an intensive care unit (ICU) in a participating centre at the time of the study and who underwent ECMO. All patients who received ECMO support for respiratory failure, cardiac failure, or cardiac arrest during their ICU stay were eligible for this study. The primary outcome was death or moderate-to-severe disability (defined using the WHO Disability Assessment Schedule 2.0, 12-item survey) at 6 months after ECMO initiation. We used Fisher's exact test to compare categorical variables. This study is registered with ClinicalTrials.gov, NCT03793257.

FINDINGS

Outcome data were available for 391 (88%) of 442 enrolled patients. The primary outcome of death or moderate-to-severe disability at 6 months was reported in 260 (66%) of 391 patients: 136 (67%) of 202 who received veno-arterial (VA)-ECMO, 60 (54%) of 111 who received veno-venous (VV)-ECMO, and 64 (82%) of 78 who received extracorporeal cardiopulmonary resuscitation (eCPR). After adjustment for age, comorbidities, Acute Physiology and Chronic Health Evaluation (APACHE) IV score, days between ICU admission and ECMO start, and use of vasopressors before ECMO, death or moderate-to-severe disability was higher in patients who received eCPR than in those who received VV-ECMO (VV-ECMO vs eCPR: risk difference [RD] -32% [95% CI -49 to -15]; p&lt;0·001) but not VA-ECMO (VA-ECMO vs eCPR -8% [-22 to 6]; p=0·27).

INTERPRETATION

In our study, only a third of patients were alive without moderate-to-severe disability at 6 months after initiation of ECMO. The finding that disability was common across all areas of functioning points to the need for long-term, multidisciplinary care and support for surviving patients who have had ECMO. Further studies are needed to understand the 180-day and longer-term prognosis of patients with different diagnoses receiving different modes of ECMO, which could have important implications for the selection of patients for ECMO and management strategies in the ICU.

FUNDING

The National Health and Medical Research Council of Australia.

Comparison of 6-Month Outcomes of Survivors of COVID-19 versus Non-COVID-19 Critical Illness

Rationale: The outcomes of survivors of critical illness due to coronavirus disease (COVID-19) compared with non-COVID-19 are yet to be established. Objectives: We aimed to investigate new disability at 6 months in mechanically ventilated patients admitted to Australian ICUs with COVID-19 compared with non-COVID-19. Methods: We included critically ill patients with COVID-19 and non-COVID-19 from two prospective observational studies. Patients were eligible if they were adult (age ⩾ 8 yr) and received ⩾24 hours of mechanical ventilation. In addition, patients with COVID-19 were eligible with a positive laboratory PCR test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Measurements and Main Results: Demographic, intervention, and hospital outcome data were obtained from electronic medical records. Survivors were contacted by telephone for functional outcomes with trained outcome assessors using the World Health Organization Disability Assessment Schedule 2.0. Between March 6, 2020, and April 21, 2021, 120 critically ill patients with COVID-19, and between August 2017 and January 2019, 199 critically ill patients without COVID-19, fulfilled the inclusion criteria. Patients with COVID-19 were older (median [interquartile range], 62 [55-71] vs. 58 [44-69] yr; P = 0.019) with a lower Acute Physiology and Chronic Health Evaluation II score (17 [13-20] vs. 19 [15-23]; P = 0.011). Although duration of ventilation was longer in patients with COVID-19 than in those without COVID-19 (12 [5-19] vs. 4.8 [2.3-8.8] d; P < 0.001), 180-day mortality was similar between the groups (39/120 [32.5%] vs. 70/199 [35.2%]; P = 0.715). The incidence of death or new disability at 180 days was similar (58/93 [62.4%] vs. 99/150 [66/0%]; P = 0.583). Conclusions: At 6 months, there was no difference in new disability for patients requiring mechanical ventilation for acute respiratory failure due to COVID-19 compared with non-COVID-19. Clinical trial registered with www.clinicaltrials.gov (NCT04401254).

The impact of COVID-19 critical illness on new disability, functional outcomes and return to work at 6 months: a prospective cohort study

BACKGROUND

There are few reports of new functional impairment following critical illness from COVID-19. We aimed to describe the incidence of death or new disability, functional impairment and changes in health-related quality of life of patients after COVID-19 critical illness at 6 months.

METHODS

In a nationally representative, multicenter, prospective cohort study of COVID-19 critical illness, we determined the prevalence of death or new disability at 6 months, the primary outcome. We measured mortality, new disability and return to work with changes in the World Health Organization Disability Assessment Schedule 2.0 12L (WHODAS) and health status with the EQ5D-5LTM.

RESULTS

Of 274 eligible patients, 212 were enrolled from 30 hospitals. The median age was 61 (51-70) years, and 124 (58.5%) patients were male. At 6 months, 43/160 (26.9%) patients died and 42/108 (38.9%) responding survivors reported new disability. Compared to pre-illness, the WHODAS percentage score worsened (mean difference (MD), 10.40% [95% CI 7.06-13.77]; p < 0.001). Thirteen (11.4%) survivors had not returned to work due to poor health. There was a decrease in the EQ-5D-5LTM utility score (MD, - 0.19 [- 0.28 to - 0.10]; p < 0.001). At 6 months, 82 of 115 (71.3%) patients reported persistent symptoms. The independent predictors of death or new disability were higher severity of illness and increased frailty.

CONCLUSIONS

At six months after COVID-19 critical illness, death and new disability was substantial. Over a third of survivors had new disability, which was widespread across all areas of functioning. Clinical trial registration NCT04401254 May 26, 2020.

Age of red blood cells is not associated with in-hospital mortality in massively transfused patients

BACKGROUND

Studies comparing mortality following massive transfusion (MT) with fresher versus longer-stored red blood cells (RBCs) have focused on trauma patients. The Australian and New Zealand Massive Transfusion Registry collects data on all adult MT cases (≥5 RBCs within 4 hours, any bleeding context, ≥18 years) at participating hospitals.

METHODS

Years 2007 to 2018 data from 29 hospitals were analyzed to quantify the association between mortality and RBC storage time in adult MT cases. We ran three logistic regression models separately on each of seven bleeding contexts, with in-hospital mortality as the outcome and, in turn, (1) mean storage time (STmean) quartiles, (2) proportion of RBCs ≥30 days old (propOLD), and (3) scalar age of blood index as predictors.

RESULTS

A total of 8,685 adult MT cases involving transfusion of 126,622 RBCs were analyzed with Australian and New Zealand data analyzed separately. Mean storage times for these cases were (by quartile in ascending order) as follows: Australia, 12.5 days (range, 3.1-15.5 days), 17.7 (15.5-19.9), 22.3 (19.9-24.9), and 29.8 (24.9-41.7); New Zealand, 11.3 days (3.6-13.7), 15.3 (13.7-16.8), 18.7 (16.8-20.7), and 24.5 (20.7-35.6). The odds ratios comparing in-hospital mortality for each quartile with that of the control first quartile (freshest blood), proportion of longer-stored (≥30 days) RBCs, and scalar age of blood index were not statistically significant across all bleeding contexts.

CONCLUSION

We find no correlation between in-hospital mortality and storage time of transfused RBCs in a large cohort of adult MT patients representing all bleeding contexts. These results are consistent with those of recent large multicenter trials.

LEVEL OF EVIDENCE

Epidemiologic, level III; Therapeutic, level IV.

Imaging mass spectrometry: a new way to distinguish dermal contact from administration of cocaine, using a single fingerprint

Here we show a new and significant application area for mass spectrometry imaging. The potential for fingerprints to reveal drug use has been widely reported, with potential applications in forensics and workplace drug testing. However, one unsolved issue is the inability to distinguish between drug administration and contamination by contact. Previous work using bulk mass spectrometry analysis has shown that this distinction can only be definitively made if the hands are washed prior to sample collection. Here, we illustrate how three mass spectrometry imaging approaches, desorption electrospray ionisation (DESI), matrix assisted laser desorption ionisation (MALDI) and time of flight secondary ion mass spectrometry (ToF-SIMS) can be used to visualise fingerprints at different pixel sizes, ranging from the whole fingerprint down to the pore structure. We show how each of these magnification scales can be used to distinguish between cocaine use and contact. We also demonstrate the first application of water cluster SIMS to a fingerprint sample, which was the sole method tested here that was capable of detecting excreted drug metabolites in fingerprints, while providing spatial resolution sufficient to resolve individual pore structure. We show that after administration of cocaine, lipids and salts in the fingerprint ridges spatially correlate with the cocaine metabolite, benzoylecgonine. In contrast after contact, we have observed that cocaine and its metabolite show a poor spatial correlation with the flow of the ridges.

A survey of extracorporeal membrane oxygenation practice in 23 Australian adult intensive care units

In Australia, extracorporeal membrane oxygenation (ECMO) is one of the most expensive diagnosis-related groups, costing $305 463 per complex admission to the intensive care unit(ICU). Mortality in this group of patients is high, about 43% for respiratory failure and 68% for cardiac failure. ECMO is associated with significant risk to the patient and requires specialist training andexpertise. Variation in clinical practice for patients supported with ECMO may compromise patient care and outcomes.

On the relevance of cocaine detection in a fingerprint

The finding that drugs and metabolites can be detected from fingerprints is of potential relevance to forensic science and as well as toxicology and clinical testing. However, discriminating between dermal contact and ingestion of drugs has never been verified experimentally. The inability to interpret the result of finding a drug or metabolite in a fingerprint has prevented widespread adoption of fingerprints in drug testing and limits the probative value of detecting drugs in fingermarks. A commonly held belief is that the detection of metabolites of drugs of abuse in fingerprints can be used to confirm a drug has been ingested. However, we show here that cocaine and its primary metabolite, benzoylecgonine, can be detected in fingerprints of non-drug users after contact with cocaine. Additionally, cocaine was found to persist above environmental levels for up to 48 hours after contact. Therefore the detection of cocaine and benzoylecgonine (BZE) in fingermarks can be forensically significant, but do not demonstrate that a person has ingested the substance. In contrast, the data here shows that a drug test from a fingerprint (where hands can be washed prior to donating a sample) CAN distinguish between contact and ingestion of cocaine. If hands were washed prior to giving a fingerprint, BZE was detected only after the administration of cocaine. Therefore BZE can be used to distinguish cocaine contact from cocaine ingestion, provided donors wash their hands prior to sampling. A test based on the detection of BZE in at least one of two donated fingerprint samples has accuracy 95%, sensitivity 90% and specificity of 100% (n = 86).

Randomised evaluation of active control of temperature versus ordinary temperature management (REACTOR) trial

PURPOSE

It is unknown whether protocols targeting systematic prevention and treatment of fever achieve lower mean body temperature than usual care in intensive care unit (ICU) patients. The objective of the Randomised Evaluation of Active Control of temperature vs. ORdinary temperature management trial was to confirm the feasibility of such a protocol with a view to conducting a larger trial.

METHODS

We randomly assigned 184 adults without acute brain pathologies who had a fever in the previous 12 h, and were expected to be ventilated beyond the calendar day after recruitment, to systematic prevention and treatment of fever or usual care. The primary outcome was mean body temperature in the ICU within 7 days of randomisation. Secondary outcomes included in-hospital mortality, ICU-free days and survival time censored at hospital discharge.

RESULTS

Compared with usual temperature management, active management significantly reduced mean temperature. In both groups, fever generally abated within 72 h. The mean temperature difference between groups was greatest in the first 48 h, when it was generally in the order of 0.5 °C. Overall, 23 of 89 patients assigned to active management (25.8%) and 23 of 89 patients assigned to usual management (25.8%) died in hospital (odds ratio 1.0, 95% CI 0.51-1.96, P = 1.0). There were no statistically significant differences between groups in ICU-free days or survival to day 90.

CONCLUSIONS

Active temperature management reduced body temperature compared with usual care; however, fever abated rapidly, even in patients assigned to usual care, and the magnitude of temperature separation was small.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry Number, ACTRN12616001285448.

Sexual Dimorphism of Resting-State Network Connectivity in Healthy Ageing

OBJECTIVES

The onset of many illnesses is confounded with age and sex. Increasing age is a risk factor for the development of many illnesses, and sexual dimorphism influences brain anatomy, function, and cognition. Here, we examine frequency-specific connectivity in resting-state networks in a large sample (n = 406) of healthy aged adults.

METHOD

We quantify frequency-specific connectivity in three resting-state networks known to be implicated in age-related decline: the default mode, dorsal attention, and salience networks, using multiband functional magnetic resonance imaging. Frequency-specific connectivity was quantified in four bands: low (0.015-0.027 Hz), moderately low (0.027-0.073 Hz), moderately high (0.073-0.198 Hz), and high (0.198-0.5 Hz) frequency bands, using mean intensity and spatial extent. Differences in connectivity between the sexes in each of the three networks were examined.

RESULTS

Each network showed the largest intensity and spatial extent at low frequencies and smallest extent at high frequencies. Males showed greater connectivity than females in the salience network. Females showed greater connectivity than males in the default mode network.

DISCUSSION

Results in this healthy aged cohort are compatible with those obtained in young samples, suggesting that frequency-specific connectivity, and differences between the sexes, are maintained into older age. Our results indicate that sex should be considered as an influencing factor in studies of resting-state connectivity.

Exploring a route to a selective and sensitive portable system for explosive detection- swab spray ionisation coupled to of high-field assisted waveform ion mobility spectrometry (FAIMS)

Paper spray mass spectrometry is a rapid and sensitive tool for explosives detection but has so far only been demonstrated using high resolution mass spectrometry, which bears too high a cost for many practical applications. Here we explore the potential for paper spray to be implemented in field applications with portable mass spectrometry. This involved (a) replacing the paper substrate with a swabbing material (which we call “swab spray”) for compatibility with standard collection materials; (b) collection of explosives from surfaces; (c) an exploration of interferences within a ± 0.5 m/z window; and (d) demonstration of the use of high-field assisted waveform ion mobility spectrometer (FAIMS) for enhanced selectivity. We show that paper and Nomex® are viable collection materials, with Nomex providing cleaner spectra and therefore greater potential for integration with portable mass spectrometers. We show that sensitive detection using swab spray will require a mass spectrometer with a mass resolving power of 4000 or more. We show that by coupling the swab spray ionisation source with FAIMS, it is possible to reduce background interferences, thereby facilitating the use of a low resolving power (e.g. quadrupole) mass spectrometer.

Singapore SPICE: sedation practices in intensive care evaluation in Singapore - a prospective cohort study of the public healthcare system

INTRODUCTION

A study was conducted to describe the sedation practices of intensive care units (ICUs) in Singapore in terms of drug use, sedation depth and the incidence of delirium in both early (< 48 hours) and late (> 48 hours) periods of ICU admission.

METHODS

A prospective multicentre cohort study was conducted on patients who were expected to be sedated and ventilated for over 24 hours in seven ICUs (surgical ICU, n = 4; medical ICU, n = 3) of four major public hospitals in Singapore. Patients were followed up to 28 days or until ICU discharge, with four-hourly sedation monitoring and daily delirium assessment by trained nurses. The Richmond Agitation and Sedation Scale (RASS) and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) were used.

RESULTS

We enrolled 198 patients over a five-month period. The mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 25.3 ± 9.2, and 90.9% were emergency hospital admissions. Patients were followed up for 1,417 ICU patient days, of which 396 days were in the early period and 1,021 days were in the late period. 7,354 RASS assessments were performed. Propofol and fentanyl were the sedative agents of choice in the early and late periods, respectively. Patients were mostly in the light sedation range, especially in the late period. At least one episode of delirium was seen in 23.7% of patients.

CONCLUSION

Sedation practices in Singapore ICUs are characterised by light sedation depth and low incidence of delirium, possibly due to the drugs used.

Trauma-related admissions to intensive care units in Australia: the influence of Indigenous status on outcomes

OBJECTIVES

To investigate the admission characteristics and hospital outcomes for Indigenous and non-Indigenous patients admitted to intensive units (ICUs) after major trauma.

DESIGN, SETTING

Retrospective analysis of Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database data from 92 Australian ICUs for the 6-year period, 2010-2015.

PARTICIPANTS

Patients older than 17 years of age admitted to public hospital ICUs with a primary diagnosis of trauma.

MAIN OUTCOME MEASURES

ICU and overall hospital lengths of stay, hospital discharge destination, and ICU and overall hospital mortality rates for Indigenous and non-Indigenous patients.

RESULTS

23 804 people were admitted to Australian public hospital ICUs after major trauma; 1754 (7.4%) were Indigenous Australians. The population-standardised incidence of admissions was consistently higher for Indigenous Australians than for non-Indigenous Australians (847 per million v 251 per million population; incidence ratio, 3.37; 95% CI, 3.19-3.57). Overall hospital mortality rates were similar for Indigenous and non-Indigenous patients (adjusted odds ratio [aOR], 1.04; 95% CI, 0.82-1.31). Indigenous patients were more likely than non-Indigenous patients to be discharged to another hospital (non-Indigenous v Indigenous: aOR, 0.84; 95% CI, 0.72-0.96) less likely to be discharged home (non-Indigenous v Indigenous: aOR, 1.17; 95% CI, 1.04-1.31).

CONCLUSION

The population rate of trauma-related ICU admissions was substantially higher for Indigenous than non-Indigenous patients, but hospital mortality rates after ICU admission were similar. Indigenous patients were more likely to be discharged to a another hospital and less likely to be discharged home than non-Indigenous patients.

A cluster randomised, crossover, registry-embedded clinical trial of proton pump inhibitors versus histamine-2 receptor blockers for ulcer prophylaxis therapy in the intensive care unit (PEPTIC study): study protocol

BACKGROUND

The balance of risks and benefits with using proton pump inhibitors (PPIs) versus histamine-2 receptor blockers (H₂RB) for stress ulcer prophylaxis in patients who are invasively ventilated in the intensive care unit (ICU) is uncertain.

OBJECTIVE

To describe the study protocol and statistical analysis plan for the Proton Pump Inhibitors versus Histamine-2 Receptor Blockers for Ulcer Prophylaxis Therapy in the Intensive Care Unit (PEPTIC) study.

DESIGN, SETTING AND PARTICIPANTS

Protocol for a prospective, multicentre, randomised, open-label, cluster crossover, registry-embedded trial to be conducted in 50 ICUs in Australia, Canada, Ireland, New Zealand and the United Kingdom. The PEPTIC study will compare two approaches to stress ulcer prophylaxis in mechanically ventilated adults implemented at the level of the ICU. One approach is to use PPIs as the default therapy and the other approach is to use H2RBs as the default therapy when stress ulcer prophylaxis is prescribed. Each ICU, by random allocation, will use one approach for 6 months and will then switch to the opposite approach for the next 6 months. The PEPTIC study began recruitment in August 2016 and will complete recruitment in January 2019.

MAIN OUTCOME MEASURES

The primary end point will be in-hospital mortality. Secondary outcomes include clinically significant upper gastrointestinal bleeding, Clostridium difficile infection, ICU length of stay and hospital length of stay.

RESULTS AND CONCLUSIONS

The PEPTIC study will compare the effect on in-hospital mortality of implementing, at the level of the ICU, the use of PPI as the preferred agent for stress ulcer prophylaxis in mechanically ventilated adults in the ICU with using H₂RB as the preferred agent.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ANZCTRN 12616000481471).

Protocol summary and statistical analysis plan for the intensive care unit randomised trial comparing two approaches to oxygen therapy (ICU-ROX)

BACKGROUND

The balance of risks and benefits of conservative v standard care oxygen strategies for patients who are invasively ventilated in the intensive care unit (ICU) is uncertain.

OBJECTIVE

To describe the study protocol and statistical analysis plan for the ICU randomised trial comparing two approaches to oxygen therapy (ICU-ROX).

DESIGN, SETTING AND PARTICIPANTS

Protocol for a multicentre, randomised, participant and outcome assessor-blinded, standard care-controlled, parallel-group, two-sided superiority trial to be conducted in up to 22 ICUs in Australia and New Zealand. 1000 adults who are mechanically ventilated in the ICU and expected to remain ventilated beyond the day after recruitment will be randomly assigned to conservative oxygen therapy or standard care in a 1:1 ratio. ICU-ROX began with an internal pilot phase in September 2015. It is anticipated that recruitment will be completed in 2018.

MAIN OUTCOME MEASURES

The primary endpoint will be alive, ventilator-free days to Day 28. Secondary outcomes include 90- and 180-day all-cause mortality, survival time to 180 days, and quality of life and cognitive function at 180 days. All analyses will be conducted on an intentionto- treat basis.

RESULTS AND CONCLUSIONS

ICU-ROX will compare the effect of conservative v standard oxygen therapy in critically ill mechanically ventilated adults who are expected to be ventilated beyond the day after recruitment on ventilatorfree days to Day 28.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ANZCTRN 12615000957594).

Intensive care unit randomised trial comparing two approaches to oxygen therapy (ICU-ROX): results of the pilot phase

OBJECTIVE

The objective of the intensive care unit randomised trial comparing two approaches to oxygen therapy (ICU-ROX) pilot phase, which included the first 100 patients of an overall sample of 1000, was to examine feasibility.

DESIGN

Investigator-initiated, prospective, parallel-group, pilot randomised controlled trial.

SETTING

Six medical-surgical intensive care units (ICUs) in Australia and New Zealand, with participants recruited from September 2015 through June 2016.

PARTICIPANTS

100 patients ≥ 18 years of age who required invasive mechanical ventilation in the ICU and were expected to be receiving it beyond the next calendar day at the time of randomisation.

INTERVENTIONS

Conservative oxygen therapy or standard care.

MAIN OUTCOME MEASURES

Eligibility, recruitment rate, and separation in oxygen exposure (fraction of inspired oxygen [FiO₂] and oxygen saturation measured by pulse oximetry [SpO₂Z]).

RESULTS

94 of 99 participants (94.9%) were confirmed by study monitors to fulfil the study eligibility criteria. 3.6 patients per site per month were enrolled (95% confidence interval [CI], 2.5-4.7). Patients allocated to conservative oxygen therapy spent significantly more time on an FiO₂ of 0.21 in the ICU; median, 31.5 hours (interquartile range [IQR], 7-63.5) for conservative oxygen therapy patients v 0 hours for standard oxygen therapy patients (IQR, 0-10; midpoint difference, 21.5 hours; 95% CI, 9-34; P < 0.0001). Patients allocated to conservative oxygen therapy spent less time in the ICU with an SpO₂Z of ≥ 97% than patients allocated to standard oxygen therapy; median, 18.5 hours (IQR, 5-46) for conservative oxygen therapy patients v 32 hours for standard oxygen therapy (IQR, 17-80; midpoint difference, 13.5 hours; 95% CI, 2-25; P = 0.02).

CONCLUSIONS

Our findings confirm the feasibility of completing the ICU-ROX trial without the need for substantive changes to the study protocol for the remaining 900 trial participants.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry (ANZCTRN 12615000957594).

The haemodynamic effects of bolus versus slower infusion of intravenous crystalloid in healthy volunteers

PURPOSE

This pilot study aimed to characterise the haemodynamic effect of 1L of IV normal saline (NS) administered as a rapid versus slow infusion on cardiac output (CO), heart rate (HR), systemic blood pressures, and carotid blood flow in six healthy volunteers.

MATERIALS AND METHODS

Six healthy male volunteers aged 18-65years were randomized to receive 1L NS given over 30min or 120min. On a subsequent study session the alternate fluid regimen was administered. Haemodynamic data was gathered using a non-invasive finger arterial pressure monitor (Nexfin®), echocardiography and carotid duplex sonography. Time to micturition and urine volume was also assessed.

RESULTS

Compared to baseline, rapid infusion of 1L of saline over 30min produced a fall in Nexfin®-measured CO by 0.62L/min (p<0.001), whereas there was a marginal but significant increase during infusion of 1L NS over 120min of 0.02L/min (p<0.001). This effect was mirrored by changes in HR and blood pressure (BP) (p<0.001). There were no significant changes in carotid blood flow, time to micturition, or urine volume produced.

CONCLUSIONS

Slower infusion of 1L NS in healthy male volunteers produced a greater increase in CO, HR and BP than rapid infusion.

Protocol and statistical analysis plan for the Randomised Evaluation of Active Control of Temperature versus Ordinary Temperature Management (REACTOR) trial

BACKGROUND

Body temperature can be reduced in febrile patients in the intensive care unit using medicines and physical cooling devices, but it is not known whether systematically preventing and treating fever reduces body temperature compared with standard care.

OBJECTIVE

To describe the study protocol and statistical analysis plan for the Randomised Evaluation of Active Control of Temperature versus Ordinary Temperature Management (REACTOR) trial.

DESIGN, SETTING AND PARTICIPANTS

Protocol for a phase II, multicentre trial to be conducted in Australian and New Zealand ICUs admitting adult patients. We will recruit 184 adults without acute brain injury who are expected to be ventilated in the ICU beyond the day after randomisation. We will use open, random, parallel assignment to systematic prevention and treatment of fever, or to standard temperature management.

MAIN OUTCOME MEASURES

The primary end point will be mean body temperature, calculated from body temperatures measured 6-hourly for 7 days (168 hours) or until ICU discharge, whichever is sooner. Secondary end points are ICU-free days, in-hospital and cause-specific mortality (censored at Day 90) and survival time to Day 90 (censored at hospital discharge).

RESULTS AND CONCLUSIONS

The trial will determine whether active temperature control reduces body temperature compared with standard care. It is primarily being conducted to establish whether a phase III trial with a patient-centred end point of Day 90 mortality is justified and feasible.

Development and Validation of the Medication-Based Disease Burden Index

Background:

Medication lists offer an alternative source of data on comorbidities and disease burden.

Objective:

To develop and validate the Medication-Based Disease Burden Index (MDBI).

Methods:

A list of medications corresponding to the leading causes of global death was pilot tested and finalized by an expert panel. The resulting index was tested on drug regimens of patients at risk of medication misadventure. Criterion validity of the index was established against Charlson's index and Chronic Disease Score (CDS). Sensitivity, specificity, predictive validity, convergent and discriminant validity, and interrater and test–retest reliabilities of the index were also assessed.

Results:

The MDBI consisting of specific medications for 20 chronic medical conditions and corresponding disability weightings was developed. The MDBI was tested on 317 patients with mean ± SD Charlson's index scores of 2.8 ± 2.2 and CDS scores of 7.3 ± 2.8. Mean MDBI scores (0.33 ± 0.28) demonstrated significant correlations with Charlson's index scores (r = 0.31; p < 0.001) and CDS (r = 0.53; p < 0.001). MDBI had satisfactory sensitivity and high specificity. Age of the patients and number of medications had significant correlation with the MDBI scores, but the MDBI scores were not significantly different in males and females. MDBI scores could successfully predict death and planned or unplanned readmissions (OR = 4.7, 95% CI 1.4 to 15.5; p = 0.01). MDBI demonstrated high inter-rater (intraclass correlation coefficient [ICC] = 0.99) and test–retest reliabilities (ICC = 0.98).

Conclusions:

Initial testing suggests that MDBI could offer an alternative low-cost and convenient method for quantifying disease burden and predicting health outcomes.

ASPREE-NEURO study protocol: A randomized controlled trial to determine the effect of low-dose aspirin on cerebral microbleeds, white matter hyperintensities, cognition, and stroke in the healthy elderly

Rationale Cerebral microbleeds seen on brain magnetic resonance imaging are markers of small vessel disease, linked to cognitive dysfunction and increased ischemic and hemorrhagic stroke risk. Observational studies suggest that aspirin use may induce cerebral microbleeds, and associated overt intracranial hemorrhage, but this has not been definitively resolved. Aims ASPREE-NEURO will determine the effect of aspirin on cerebral microbleed development over three years in healthy adults aged 70 years and over, participating in the larger 'ASPirin in Reducing Events in the Elderly (ASPREE)' primary prevention study of aspirin. Sample size Five hundred and fifty-nine participants provide 75% power (two-sided p value of 0.05) to determine an average difference of 0.5 cerebral microbleed per person after three years. Methods and design A multi-center, randomized placebo-controlled trial of 100 mg daily aspirin in participants who have brain magnetic resonance imaging at study entry, one and three years after randomization and who undergo cognitive testing at the same time points. Study outcomes The primary outcome is the number of new cerebral microbleeds on magnetic resonance imaging after three years. Secondary outcomes are the number of new cerebral microbleeds after one year, change in volume of white matter hyperintensity, cognitive function, and stroke. Discussion ASPREE-NEURO will resolve whether aspirin affects the presence and number of cerebral microbleeds, their relationship with cognitive performance, and indicate whether consideration of cerebral microbleeds alters the risk-benefit profile of aspirin in primary prevention for older people. Trial registration Australian New Zealand Clinical Trials Registry ACTRN12613001313729.

Unprofessional behaviour on social media by medical students

OBJECTIVES

To describe the social media usage patterns of medical students and to identify factors associated with their posting of unprofessional content on social media.

DESIGN

Voluntary survey, delivered online.

SETTING

All students in all 20 Australian medical schools were eligible to participate (16 993 individuals).

PARTICIPANTS

Of 1027 initial respondents during the study period (29 March - 12 August 2013), 880 completed the survey.

MAIN OUTCOME MEASURES

Prevalence of unprofessional online behaviour on social media by medical students, as reported by students about their own and others' accounts.

RESULTS

Posting of unprofessional content was self-reported by 306 students (34.7%), mainly depictions of intoxication (301 students, 34.2%) or illegal drug use (14 students, 1.6%), or posting of patient information (14 students, 1.6%). Posting of unprofessional content was associated with posting evidence of alcohol use and racist content online, MySpace use, and planning to change one's profile name after graduation. Factors associated with reduced unprofessional content included believing that videos depicting medical events with heavy alcohol use were inappropriate, and being happy with one's own social media portrayal. Exposure to guidelines on professional online conduct had no effect on posting behaviour.

CONCLUSIONS

Social media use was nearly universal in the surveyed cohort. Posting of unprofessional content was highly prevalent despite understanding that this might be considered inappropriate, and despite awareness of professionalism guidelines. Medical educators should consider approaches to this problem that involve more than simply providing guidelines or policies, and students should be regularly prompted to evaluate and moderate their own online behaviour.

Insurance status and mortality in critically ill patients

OBJECTIVE

The association between insurance status and outcome in critically ill patients is uncertain. We aimed to determine if there was an independent relationship between the presence or absence of compensable insurance status and mortality, after admission to the intensive care unit.

METHODS

We performed a retrospective cohort study in five public hospitals in Victoria, comprising adult patients admitted to the ICU between 2007 and 2012. We obtained data on demographics, severity of illness, chronic health status, insurance category, length of stay (LOS) and mortality. We matched socio-economic indices (collected from the Australian Bureau of Statistics) to postcodes. The primary outcome measured was in-hospital mortality. Secondary outcomes were ICU mortality, and ICU and hospital LOS, measured in days.

RESULTS

We studied 33 306 patients. Compensable patients comprised 21.2% of the study population (7046). Personal private insurance accounted for 13.4% (4451) and Transport Accident Commission insurance for 5.1% (1701) of compensable patients. Unadjusted in-hospital mortality was higher in publicly insured patients (13.4% v 10.6%, P < 0.0001). After adjusting for age, severity of illness, diagnosis and socio-economic status, being a compensable patient in a public hospital ICU was independently associated with a reduction in mortality (odds ratio, 0.73; 95% CI, 0.65-0.80; P < 0.001).

CONCLUSIONS

Among ICU patients treated in public hospitals in Victoria, being a compensable patient appears to be independently associated with a reduction in mortality. Further studies are needed to confirm and validate these findings elsewhere in Australia.

Nutrition therapy in adult patients receiving extracorporeal membrane oxygenation: a prospective, multicentre, observational study

OBJECTIVES

To describe current nutrition delivery practices and to identify barriers to nutrition in patients receiving venovenous or venoarterial extracorporeal membrane oxygenation (ECMO) in multiple centres in Australia and New Zealand.

DESIGN, SETTING AND PARTICIPANTS

A prospective, multicentre, observational study, set in eight intensive care units in Australia and New Zealand, of adults treated with ECMO who were expected to receive enteral nutrition (EN) or parenteral nutrition (PN) therapy for > 72 hours. Data were collected from the start of ECMO until 7 days after ECMO cessation.

RESULTS

There were 107 patients enrolled, with a median age of 42 years (interquartile range [IQR], 31-56 years), and 54 patients (50%) were men. EN was the most commonly delivered mode of nutrition (on 84% of days) although it was interrupted on 53% of days. The median interruption duration was 8 hours (IQR, 4-5 hours] per episode. The two most common barriers to EN delivery were fasting for a therapeutic or diagnostic procedure and high gastric residual volumes. Median daily calorie and protein deliveries from EN and/or PN were 1680 kcal (IQR, 960-2100 kcal) and 72 g (IQR, 42-98 g) of protein. For patients who received EN and/or PN, median calorie and protein deficits during the study period were -7118 kcal (IQR, -11 614 to -4510 kcal) and -325 g (IQR, - 525 to -188 g) of protein.

CONCLUSIONS

EN was the most commonly used nutrition-delivery mode during ECMO treatment but was frequently interrupted. Compared with estimated calorie and protein requirements, lesser but reasonably acceptable amounts were delivered, although calorie and protein deficits still existed.

Effectiveness of a care bundle to reduce central line-associated bloodstream infections

OBJECTIVE

To determine the effectiveness of a care bundle, with a novel line maintenance procedure, in reducing the rate of central line-associated bloodstream infection (CLABSI) in the intensive care unit (ICU).

DESIGN, PARTICIPANTS AND SETTING

Before-and-after study using CLABSI data reported to the Victorian Healthcare Associated Infection Surveillance System (VICNISS), in adult patients admitted to a tertiary adult ICU in regional Victoria between 1 July 2006 and 30 June 2014. VICNISS-reported CLABSI cases were reviewed for verification. An intervention was implemented in 2009.

INTERVENTION

The care bundle introduced in 2009 included a previously established line insertion procedure and a novel line maintenance procedure comprising Biopatch, daily 2% chlorhexidine body wash, daily ICU central line review, and liaison nurse follow-up of central lines.

MAIN OUTCOME MEASURES

CLABSI rate (cases per 1000 central line days).

RESULTS

The average CLABSI rate fell from 2.2/1000 central line days (peak of 5.2/1000 central line days in quarter 4, 2008) during the pre-intervention period to 0.5/1000 central line days (0/1000 central line days from July 2012 to July 2014) during the post-intervention period.

CONCLUSION

Our study suggests that this care bundle, using a novel maintenance procedure, can effectively reduce the CLABSI rate and maintain it at zero out to 2 years.

Procalcitonin algorithm in critically ill adults with undifferentiated infection or suspected sepsis. A randomized controlled trial

RATIONALE

The role of procalcitonin (PCT), a widely used sepsis biomarker, in critically ill patients with sepsis is undetermined.

OBJECTIVES

To investigate the effect of a low PCT cut-off on antibiotic prescription and to describe the relationships between PCT plasma concentration and sepsis severity and mortality.

METHODS

This was a multicenter (11 Australian intensive care units [ICUs]), prospective, single-blind, randomized controlled trial involving 400 patients with suspected bacterial infection/sepsis and expected to receive antibiotics and stay in ICU longer than 24 hours. The primary outcome was the cumulative number of antibiotics treatment days at Day 28.

MEASUREMENTS AND MAIN RESULTS

PCT was measured daily while in the ICU. A PCT algorithm, including 0.1 ng/ml cut-off, determined antibiotic cessation. Published guidelines and antimicrobial stewardship were used in all patients. Primary analysis included 196 (PCT) versus 198 standard care patients. Ninety-three patients in each group had septic shock. The overall median (interquartile range) number of antibiotic treatment days were 9 (6-21) versus 11 (6-22), P = 0.58; in patients with positive pulmonary culture, 11 (7-27) versus 15 (8-27), P = 0.33; and in patients with septic shock, 9 (6-22) versus 11 (6-24), P = 0.64; with an overall 90-day all-cause mortality of 35 (18%) versus 31 (16%), P = 0.54 in the PCT versus standard care, respectively. Using logistic regression, adjusted for age, ventilation status, and positive culture, the decline rate in log(PCT) over the first 72 hours independently predicted hospital and 90-day mortality (odds ratio [95% confidence interval], 2.76 [1.10-6.96], P = 0.03; 3.20 [1.30-7.89], P = 0.01, respectively).

CONCLUSIONS

In critically ill adults with undifferentiated infections, a PCT algorithm including 0.1 ng/ml cut-off did not achieve 25% reduction in duration of antibiotic treatment. Clinical trial registered with http://www.anzctr.org.au (ACTRN12610000809033).

Overview of the study protocols and statistical analysis plan for the Saline versus Plasma-Lyte 148 for Intravenous Fluid Therapy (SPLIT) research program

BACKGROUND

0.9% saline is the most commonly used intravenous (IV) fluid in the world but recent data raise the possibility that, compared with buffered crystalloid fluids such as Plasma-Lyte 148, the administration of 0.9% saline might increase the risk of developing acute kidney injury.

OBJECTIVE

To provide an overview of the study protocols and statistical analysis plan for the six studies making up the (0.9% Saline v Plasma-Lyte 148 for Intravenous Fluid Therapy (SPLIT) research program.

METHODS

The SPLIT study consists of six integrated clinical trials, including a double-blind, cluster, randomised, double-crossover study in intensive care unit patients, incorporating two nested studies within it; an open-label, before-and-after study in emergency department (ED) patients; a single-centre, double-blind, crossover trial in major surgical patients; and a randomised, double-blind study in ICU patients. All studies focus on biochemical and renal outcomes but will also provide preliminary data on patient-centred outcomes including inhospital mortality and requirements for dialysis.

RESULTS AND CONCLUSION

The SPLIT study program will provide preliminary data on the comparative effectiveness of using 0.9% saline v Plasma-Lyte 148 for IV fluid therapy in ED, surgical and ICU patients.

Complementary medicine use by people living with HIV in Australia - a national survey

Little is known about the use of complementary medicines by people living with HIV in Australia since the advent of more effective combination antiretroviral therapy. We conducted an anonymous survey of 1211 adult patients receiving combination antiretroviral therapy from one of eight specialist HIV clinics across Australia, aiming to identify the current patterns of use of ingestible complementary medicines. Data collected included reasons for use, information sources and rates of disclosure of use of complementary medicines to medical practitioners and pharmacists. Ingestible complementary medicine was used by up to 53% of the 1037 patients returning a survey. Complementary medicine was commonly used for general health, to boost immune function and, to a lesser extent, to address co-morbidities. Disclosure of complementary medicines use to doctors was far higher than to pharmacists. Given the potential for interactions, pharmacists should be more aware of patients' complementary medicines use.

A protocol for the 0.9% saline versus Plasma-Lyte 148 for intensive care fluid therapy (SPLIT) study

BACKGROUND

0.9% saline is the most commonly used intravenous (IV) fluid in the world. However, recent data raise the possibility that, compared with buffered crystalloid fluids such as Plasma-Lyte 148, the administration of 0.9% saline to intensive care unit patients might increase their risk of acute kidney injury (AKI).

OBJECTIVE

To describe the protocol for the 0.9% Saline v Plasma-Lyte 148 for ICU Fluid Therapy (SPLIT) study.

METHODS

This is a multicentre, cluster-randomised, double crossover feasibility study to be conducted in four New Zealand tertiary ICUs over a 28-week period and will enroll about 2300 participants. All ICU patients who need crystalloid IV fluid therapy (except those with established renal failure needing dialysis and those admitted to the ICU for palliative care) will be enrolled. Participating ICUs will be randomly assigned to 0.9% saline or Plasma-Lyte 148 as the routine crystalloid IV fluid, in a blinded fashion, in four alternating 7-week blocks.

MAIN OUTCOME MEASURES

The primary outcome will be the proportion of patients who develop AKI in the ICU. Secondary outcomes will include the difference between the most recent serum creatinine level measured before study enrollment and the peak serum creatinine level in the ICU; use of renal replacement therapy; and ICU and in hospital mortality. All analyses will be conducted on an intention-to-treat basis.

RESULTS AND CONCLUSION

The SPLIT study started on 1 April 2014 and will provide preliminary data on the comparative effectiveness of using 0.9% saline v Plasma- Lyte 148 as the routine IV fluid therapy in ICU patients.

Opinions and practice of stress ulcer prophylaxis in Australian and New Zealand intensive care units

BACKGROUND

Intensivists frequently prescribe proton pump inhibitors (PPIs) or histamine-2 receptor blockers (H2RBs) to intensive care unit patients for stress ulcer prophylaxis (SUP). Despite the common use of SUP medicines, there is limited high-level evidence to support the choice between them.

AIM

To describe self-reported practice of SUP by Australian and New Zealand intensivists.

METHOD

An online questionnaire of intensivists between 13 January and 3 February 2014.

RESULTS

Seventy-two intensivists responded to the survey: 61 (85%) practised in public metropolitan ICUs and 13/48 (27%) practised in paediatric ICUs. Fifty-two (72%) respondents indicated that PPIs were their preferred SUP medicine. Respondents estimated that an average of 84% of ventilated and 53% of non-ventilated patients received SUP medicines during their ICU admission. Seven respondents (9%) were concerned or very concerned about the possible increased risk of upper gastrointestinal bleeding associated with H2RBs versus PPIs. Ten respondents (14%) were concerned or very concerned about the possible greater risk of Clostridium difficile infection, and 15 respondents (21%) were concerned or very concerned about the possible greater risk or ventilator-associated pneumonia with PPIs versus H2RBs. Most respondents (64 [89%]) agreed or strongly agreed that there was insufficient evidence to support the choice of an optimal SUP medicine, and 58 respondents (81%) agreed or strongly agreed to patient enrollment in an RCT comparing PPIs with H2RBs.

CONCLUSION

Most survey respondents felt that current evidence is insufficient to justify the preferential use of PPIs or H2RBs for SUP and would enroll patients in a comparative SUP RCT.

A multicentre feasibility study evaluating stress ulcer prophylaxis using hospital-based registry data

BACKGROUND

It is unclear whether histamine-2 receptor blockers (H2RBs) or proton pump inhibitors (PPIs) are preferred for stress ulcer prophylaxis (SUP) in intensive care unit patients. Suitably powered comparative effectiveness trials are warranted.

OBJECTIVE

To establish the feasibility of collecting process-of-care and outcome data relevant to a proposed interventional trial of SUP using existing databases.

DESIGN, SETTING AND PARTICIPANTS

A retrospective cohort study conducted in seven Australia and New Zealand tertiary ICUs, including all patients ≥18 years admitted between 1 January 2011 and 31 December 2012.

MAIN OUTCOME MEASURES

Doses of dispensed PPIs and H2RBs, upper gastrointestinal bleeding events, upper respiratory tract colonisation with pathogenic bacteria, Clostridium difficile infections and inhospital mortality.

RESULTS

All sites were able to contribute to the study and investigators reported that data were generally easy to obtain. A median dose/ICU of 477 g of PPIs (interquartile range [IQR], 430.5-865 g), and 408.5 g (IQR, 109-1630.2 g) of H2RBs, were dispensed over the 2 years of the study. The median proportion of patients/ICU with upper GI bleeding complicating admission was 1.4% (IQR, 0.3%-1.8%). Colonisation of the respiratory tract with gram-negative bacteria occurred in a median of 7.1% of patients/ICU (IQR, 6.3%-14.1%). Pseudomembranous colitis occurred in hospital in a median of 1.4% of patients (IQR, 0.9%-2%) and inhospital mortality was 10.6% (95% CI, 9.5%- 11.7%).

CONCLUSIONS

It is feasible to use existing data sources to measure process-of-care and outcome data necessary for a registry-based interventional trial of SUP.

Scale-up of hydrophobin-assisted recombinant protein production in tobacco BY-2 suspension cells

Plant suspension cell cultures are emerging as an alternative to mammalian cells for production of complex recombinant proteins. Plant cell cultures provide low production cost, intrinsic safety and adherence to current regulations, but low yields and costly purification technology hinder their commercialization. Fungal hydrophobins have been utilized as fusion tags to improve yields and facilitate efficient low-cost purification by surfactant-based aqueous two-phase separation (ATPS) in plant, fungal and insect cells. In this work, we report the utilization of hydrophobin fusion technology in tobacco bright yellow 2 (BY-2) suspension cell platform and the establishment of pilot-scale propagation and downstream processing including first-step purification by ATPS. Green fluorescent protein-hydrophobin fusion (GFP-HFBI) induced the formation of protein bodies in tobacco suspension cells, thus encapsulating the fusion protein into discrete compartments. Cultivation of the BY-2 suspension cells was scaled up in standard stirred tank bioreactors up to 600 L production volume, with no apparent change in growth kinetics. Subsequently, ATPS was applied to selectively capture the GFP-HFBI product from crude cell lysate, resulting in threefold concentration, good purity and up to 60% recovery. The ATPS was scaled up to 20 L volume, without loss off efficiency. This study provides the first proof of concept for large-scale hydrophobin-assisted production of recombinant proteins in tobacco BY-2 cell suspensions.

Diabetes is a major risk factor for mortality after lung transplantation

Survival following lung transplant (LTx) remains significantly lower than after other solid organ transplants. Diabetes mellitus (DM) is a mortality risk factor not comprehensively studied in LTx recipients. Notably, neither the relation of time of DM onset to survival nor the actual causes of DM-associated excess mortality have been described. We determined DM status, DM diagnosis date and all-cause mortality in 386 consecutive adults who underwent LTx at our institution from January 1, 2001 to July 31, 2010. The relationship of DM to survival both as a categorical and time-dependent variable was studied. Fifty-three percent of patients had DM. Overall median survival was 5.2 (95% CI 3.8-6.6) years. At study end, 52% of patients had died, of whom 64% had DM. Estimated median survival was 10 years in patients without DM, 5.0 (3.3-6.8) years in patients with DM pre- and post-LTx and 4.3 (3.1-5.5) years in patients with new onset DM. As a time-dependent covariate, DM was the strongest risk factor for mortality, hazard ratio 3.96 (2.85-5.51). Bronchiolitis obliterans syndrome was the main cause of death in all patients surviving >90 days, but its incidence was not increased in patients with DM. Further studies are warranted to determine whether improved glycemic control could improve outcomes in LTx recipients.

Hyperoxia in the intensive care unit and outcome after out-of-hospital ventricular fibrillation cardiac arrest

BACKGROUND

Laboratory and clinical studies have suggested that hyperoxia early after resuscitation from cardiac arrest may increase neurological injury and worsen outcome. Previous clinical studies have been small or have not included relevant prehospital data. We aimed to determine in a larger cohort of patients whether hyperoxia in the intensive care unit in patients admitted after out-of-hospital cardiac arrest (OHCA) was associated with increased mortality rate after correction for prehospital variables.

METHODS

Data from the Victorian Ambulance Cardiac Arrest Registry (VACAR) of patients transported to hospital after resuscitation from OHCA and an initial cardiac rhythm of ventricular fibrillation between January 2007 and December 2011 were linked to the Australian and New Zealand Intensive Care Society Adult Patient Database (ANZICS-APD). Patients were allocated into three groups (hypoxia [PaO2<60mmHg], normoxia [PaO2,60-299mmHg] or hyperoxia [PaO2≥300mmHg]) according to their most abnormal PaO2 level in the first 24 hours of ICU stay. The relationship between PaO2 and hospital mortality was investigated using multivariate logistic regression analysis to adjust for confounding prehospital and ICU factors.

RESULTS

There were 957 patients identified on the VACAR database who met inclusion criteria. Of these, 584 (61%) were matched to the ANZICS-APD and had hospital mortality and oxygen data available. The unadjusted hospital mortality was 51% in the hypoxia patients, 41% in the normoxia patients and 47% in the hyperoxia patients (P=0.28). After adjustment for cardiopulmonary resuscitation by a bystander, patient age and cardiac arrest duration, hyperoxia in the ICU was not associated with increased hospital mortality (OR, 1.2; 95% CI, 0.51-2.82; P=0.83).

CONCLUSIONS

Hyperoxia within the first 24 hours was not associated with increased hospital mortality in patients admitted to ICU following out-of-hospital ventricular fibrillation cardiac arrest.

Adherence to acceptability and repeatability criteria for spirometry in complex lung function laboratories

BACKGROUND

Few published data exist for adherence rates to spirometry acceptability and repeatability criteria in clinical respiratory laboratories. This study quantified adherence levels in this setting and observed changes in adherence levels as a result of feedback and ongoing training.

METHODS

Two tertiary hospital-based, lung function laboratories (L1 and L2) participated. Approximately 100 consecutive, FVC spirometry sessions were reviewed for each year from 2004 to 2008 at L1 and for years 2004 and 2008 at L2. Each spirometric effort and session was interrogated for adherence to the acceptability and repeatability criteria of international spirometry standards of the time. Feedback of audit results and refresher training were provided at L1 throughout the study; in addition, a quality rating scale was implemented in 2006. No formal feedback or follow-up training was provided at L2.

RESULTS

We reviewed 707 test sessions over the 5 years. There was no difference in adherence rates to acceptability and repeatability criteria between sites in 2004 (L1 61%, L2 59%, P = .89). There was, however, a significant difference between sites in 2008 (L1 92%, L2 65%, P < .001). No difference was seen at L2 between 2004 and 2008 (P = .26), while L1 experienced a significant increase in adherence levels between 2004 and 2008 (61% to 92% P < .001).

CONCLUSIONS

Clinical respiratory laboratories met published spirometry acceptability and repeatability criteria only 60% of the time in the first audit period. This improved with regular review, feedback, and implementation of a rating scale. Auditing of spirometry quality, feedback, and implementation of test rating scales need to be incorporated as an integral component of laboratory quality assurance programs to improve adherence to international acceptability and repeatability criteria.

Prophylactic perioperative sodium bicarbonate to prevent acute kidney injury following open heart surgery: a multicenter double-blinded randomized controlled trial

BACKGROUND

Preliminary evidence suggests a nephroprotective effect of urinary alkalinization in patients at risk of acute kidney injury. In this study, we tested whether prophylactic bicarbonate-based infusion reduces the incidence of acute kidney injury and tubular damage in patients undergoing open heart surgery.

METHODS AND FINDINGS

In a multicenter, double-blinded (patients, clinical and research personnel), randomized controlled trial we enrolled 350 adult patients undergoing open heart surgery with the use of cardiopulmonary bypass. At induction of anesthesia, patients received either 24 hours of intravenous infusion of sodium bicarbonate (5.1 mmol/kg) or sodium chloride (5.1 mmol/kg). The primary endpoint was the proportion of patients developing acute kidney injury. Secondary endpoints included the magnitude of acute tubular damage as measured by urinary neutrophil gelatinase-associated lipocalin (NGAL), initiation of acute renal replacement therapy, and mortality. The study was stopped early under recommendation of the Data Safety and Monitoring Committee because interim analysis suggested likely lack of efficacy and possible harm. Groups were non-significantly different at baseline except that a greater proportion of patients in the sodium bicarbonate group (66/174 [38%]) presented with preoperative chronic kidney disease compared to control (44/176 [25%]; p = 0.009). Sodium bicarbonate increased urinary pH (from 6.0 to 7.5, p<0.001). More patients receiving bicarbonate (83/174 [47.7%]) developed acute kidney injury compared with control patients (64/176 [36.4%], odds ratio [OR] 1.60 [95% CI 1.04-2.45]; unadjusted p = 0.032). After multivariable adjustment, a non-significant unfavorable group difference affecting patients receiving sodium bicarbonate was found for the primary endpoint (OR 1.45 [0.90-2.33], p = 0.120]). A greater postoperative increase in urinary NGAL in patients receiving bicarbonate infusion was observed compared to control patients (p = 0.011). The incidence of postoperative renal replacement therapy was similar but hospital mortality was increased in patients receiving sodium bicarbonate compared with control (11/174 [6.3%] versus 3/176 [1.7%], OR 3.89 [1.07-14.2], p = 0.031).

CONCLUSIONS

Urinary alkalinization using sodium bicarbonate infusion was not found to reduce the incidence of acute kidney injury or attenuate tubular damage following open heart surgery; however, it was associated with a possible increase in mortality. On the basis of these findings we do not recommend the prophylactic use of sodium bicarbonate infusion to reduce the risk of acute kidney injury. Discontinuation of growing implementation of this therapy in this setting seems to be justified.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00672334 Please see later in the article for the Editors' Summary.

Long-term quality of life in patients with acute respiratory distress syndrome requiring extracorporeal membrane oxygenation for refractory hypoxaemia

INTRODUCTION

The purpose of the study was to assess the long term outcome and quality of life of patients with acute respiratory distress syndrome (ARDS) receiving extracorporeal membrane oxygenation (ECMO) for refractory hypoxemia.

METHODS

A retrospective observational study with prospective health related quality of life (HRQoL) assessment was conducted in ARDS patients who had ECMO as a rescue therapy for reversible refractory hypoxemia from January 2009 until April 2011 in a tertiary Australian centre. Survival and long-term quality of life assessment, using the Short-Form 36 (SF-36) and the EuroQol health related quality of life questionnaire (EQ5D) were assessed and compared to international data from other research groups.

RESULTS

Twenty-one patients (mean age 36.3 years) with ARDS receiving ECMO for refractory hypoxemia were studied. Eighteen (86%) patients were retrieved from external intensive care units (ICUs) by a dedicated ECMO retrieval team. Eleven (55%) had H1N1 influenza A-associated pneumonitis. Eighteen (86%) patients survived to hospital discharge. Of the 18 survivors, ten (56%) were discharged to other hospitals and 8 (44%) were discharged directly home. Sequelae and health related quality of life were evaluated for 15 of the 18 (71%) long-term survivors (assessment at median 8 months). Mean SF-36 scores were significantly lower across all domains compared to age and sex matched Australian norms. Mean SF-36 scores were lower (minimum important difference at least 5 points) than previously described ARDS survivors in the domains of general health, mental health, vitality and social function. One patient had long-term disability as a result of ICU acquired weakness. Only 26% of survivors had returned to previous work levels at the time of follow-up.

CONCLUSIONS

This ARDS cohort had a high survival rate (86%) after use of ECMO support for reversible refractory hypoxemia. Long term survivors had similar physical health but decreased mental health, general health, vitality and social function compared to other ARDS survivors and an unexpectedly poor return to work.

Evaluation of particle-induced X-ray emission and particle-induced γ-ray emission of quartz grains for forensic trace sediment analysis

The independent verification in a forensics context of quartz grain morphological typing by scanning electron microscopy was demonstrated using particle-induced X-ray emission (PIXE) and particle-induced γ-ray emission (PIGE). Surface texture analysis by electron microscopy and high-sensitivity trace element mapping by PIXE and PIGE are independent analytical techniques for identifying the provenance of quartz in sediment samples in forensic investigations. Trace element profiling of the quartz grain matrix separately from the quartz grain inclusions served to differentiate grains of different provenance and indeed went some way toward discriminating between different quartz grain types identified in a single sample of one known forensic provenance. These results confirm the feasibility of independently verifying the provenance of critical samples from forensic cases.