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.