Environmental and financial impacts of perioperative paracetamol use: a multicentre international life-cycle analysis.

BACKGROUND: Pharmaceuticals account for 19-32% of healthcare greenhouse gas (GHG) emissions. Paracetamol is a common perioperative analgesic agent. We estimated GHG emissions associated with i.v. and oral formulations of paracetamol used in the perioperative period. METHODS: Life-cycle assessment of GHG emissions (expressed as carbon dioxide equivalents CO2e) of i.v. and oral paracetamol preparations was performed. Perioperative paracetamol prescribing practices and costs for 26 hospitals in USA, UK, and Australia were retrospectively audited. For those surgical patients for whom oral formulations were indicated, CO2e and costs of actual prescribing practices for i.v. or oral doses were compared with optimal oral prescribing. RESULTS: The carbon footprint for a 1 g dose was 38 g CO2e (oral tablet), 151 g CO2e (oral liquid), and 310-628 g CO2e (i.v. dependent on type of packaging and administration supplies). Of the eligible USA patients, 37% received paracetamol (67% was i.v.). Of the eligible UK patients, 85% received paracetamol (80% was i.v.). Of the eligible Australian patients, 66% received paracetamol (70% was i.v.). If the emissions mitigation opportunity from substituting oral tablets for i.v. paracetamol is extrapolated to USA, UK, and Australia elective surgical encounters in 2019, ∼5.7 kt CO2e could have been avoided and would save 98.3% of financial costs. CONCLUSIONS: Intravenous paracetamol has 12-fold greater life-cycle carbon emissions than the oral tablet form. Glass vials have higher greenhouse gas emissions than plastic vials. Intravenous administration should be reserved for cases in which oral formulations are not feasible.

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

BACKGROUND: Prone positioning may improve oxygenation in acute hypoxemic respiratory failure and was widely adopted in COVID-19 patients. However, the magnitude and timing of its peak oxygenation effect remain uncertain with the optimum dosage unknown. Therefore, we aimed to investigate the magnitude of the peak effect of prone positioning on the PaO2 :FiO2 ratio during prone and secondly, the time to peak oxygenation. METHODS: Multi-centre, observational study of invasively ventilated adults with acute hypoxemic respiratory failure secondary to COVID-19 treated with prone positioning. Baseline characteristics, prone positioning and patient outcome data were collected. All arterial blood gas (ABG) data during supine, prone and after return to supine position were analysed. The magnitude of peak PaO2 :FiO2 ratio effect and time to peak PaO2 :FIO2 ratio effect was measured. RESULTS: We studied 220 patients (mean age 54 years) and 548 prone episodes. Prone positioning was applied for a mean (±SD) 3 (±2) times and 16 (±3) hours per episode. Pre-proning PaO2 :FIO2 ratio was 137 (±49) for all prone episodes. During the first episode. the mean PaO2 :FIO2 ratio increased from 125 to a peak of 196 (p < .001). Peak effect was achieved during the first episode, after 9 (±5) hours in prone position and maintained until return to supine position. CONCLUSIONS: In ventilated adults with COVID-19 acute hypoxemic respiratory failure, peak PaO2 :FIO2 ratio effect occurred during the first prone positioning episode and after 9 h. Subsequent episodes also improved oxygenation but with diminished effect on PaO2 :FIO2 ratio. This information can help guide the number and duration of prone positioning episodes.

It's time to stop using nitrous oxide for pediatric mask induction.

BACKGROUND: Mask induction of anesthesia for pediatric patients has included the use of nitrous oxide since the inception of pediatric anesthesia. However, the use of nitrous oxide precludes adequate preoxygenation. Additionally, pediatric physiology (less Functional Residual Capacity, higher oxygen consumption), increased risk of laryngospasm and lack of intravenous access increase the risk of a severe airway complication in the event of airway occlusion. Nitrous oxide does not facilitate tranquil mask placement on an unwilling child and does not meaningfully speed mask induction. Exposure to nitrous oxide has potential occupational health concerns and nitrous oxide has significant environmental detriment. CONCLUSION: Utilizing other, evidence-based, techniques to facilitate tranquil mask placement will assure that patients have a pleasant induction experience and avoiding nitrous oxide will reduce the environmental impact, as well as improve the safety of, pediatric mask induction.

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

BACKGROUND: The Impella (Abiomed, Danvers, MA, USA) temporary percutaneous left ventricular assist device is increasingly used as mechanical circulatory support in patients with acute myocardial infarction-cardiogenic shock (AMICS) or those undergoing high-risk protected percutaneous coronary intervention (PCI). The optimal weaning regimen remains to be defined. METHOD: We implemented a structured weaning protocol in a series of 10 consecutive patients receiving Impella support for protected PCI or AMICS treated with PCI in a high volume non-cardiac surgery centre. Weaning after revascularisation was titrated to native heart recovery using both haemodynamic and echocardiographic parameters. RESULTS: Ten patients (eight male, two female; aged 43-70 years) received Impella support for AMICS (80%) or protected PCI (20%). Cardiogenic shock was of Society for Cardiac Angiography & Interventions grade C-E of severity in 80%, and median left ventricular end-diastolic pressure was 31 mmHg. Protocol implementation allowed successful weaning in eight of 10 patients with a median support time of 29 hours (range, 4-48 hours). Explantation was associated with an increase in heart rate (81 vs 88 bpm; p=0.005), but no significant change in Cardiac Index (2.9 vs 2.9 L/min/m2), mean arterial pressure (79 vs 82 mmHg), vasopressor requirement (10% vs 10%), or serum lactate (1.0 vs 1.0). Median durations of intensive care and hospital stay were 3 and 6 days, respectively. At 30 days, the mortality rate was 20%, with median left ventricular ejection fraction of 40%. CONCLUSIONS: A structured and dynamic weaning protocol for patients with AMICS and protected PCI supported by the Impella device is feasible in a non-cardiac surgery centre. Larger studies are needed to assess generalisability of such a weaning protocol.

Blood gas sampling in the intensive care unit: A prospective before-and-after interventional study on the effect of an educational program on blood gas testing frequency.

BACKGROUND: Blood gas analysis is the most commonly ordered test in the intensive care unit. Each investigation, however, comes with risks and costs to the patient and healthcare system. Evidence suggests that many tests are performed with no appropriate clinical indication. OBJECTIVES: The primary aim of our prospective interventional study was to investigate the proportion of blood gases undertaken with a valid clinical indication before and after an educational intervention. A secondary aim was to examine sleep interruption secondary to blood gas sampling. METHODS: A prospective, before-and-after interventional study was conducted across two metropolitan intensive care units in Melbourne, Australia. Adults aged ≥18 years who were admitted to intensive care were eligible for inclusion. Two observation periods were conducted across a 2-week period in May and September 2022 (Periods 1 and 2), where clinicians were encouraged to record the purpose of blood gas sampling and other relevant data via an electronic questionnaire. These data were reviewed with corresponding electronic medical records. In between these periods, an interventional educational program to inform the clinical rationale for blood gas testing was delivered during July and August 2022, including introduction of a clinical guideline. RESULTS: There were 68 patients with 688 tests included in Period 1 compared to 69 patients with 756 tests in Period 2. There was no significant difference between the median number of blood gas analyses performed per patient before and after the educational intervention (6.0 tests per patient vs 5.0 tests per patient, p = 0.609). However, there was a significant increase in the percentage of tests with a valid clinical indication (49.0% vs 59.7%, p = 0.0025). The most common indications selected were routine measurement, monitoring a clinical value, change in ventilator settings/oxygen therapy, and clinical deterioration. In addition, there were a large number of patients who were awakened upon drawing of a blood sample for analysis (26.1% for Period 1 and 37.6% for Period 2, p = 0.06). CONCLUSION: The implementation of an educational program resulted in a significant increase in the proportion of blood gases performed with an appropriate clinical indication. There was, however, no reduction in the overall number of blood gases performed.

How often are infusion sets for central venous catheters changed in Australian and New Zealand Intensive Care Units? A point prevalence survey.

BACKGROUND: Infusion sets (comprising the tubing, measuring burettes, fluid containers, transducers) that are connected to invasive vascular devices are changed on a regular basis in an effort to reduce bacterial colonisation and bloodstream infection. There is a balance between reducing infection and creating unnecessary waste. Current evidence suggests that for central venous catheters (CVCs), changing infusion sets at 7 days does not increase infection risks. OBJECTIVES: The objective of this study was to describe the current unit guidelines in Australian and New Zealand intensive care units (ICUs) for changing infusion sets for CVCs. METHODS: prospective cross-sectional point prevalence study, as a part of the 2021 Australian and New Zealand Intensive Care Society Point Prevalence Program. PARTICIPANTS: Australia and New Zealand (ANZ) adult ICUs and their patients on the day of the study. RESULTS: Data were collected from 51 ICUs across ANZ. One-third of these (16/49) ICUs had a guideline that specified a 7-day replacement period, with the rest having a more frequent replacement period. CONCLUSION: Most ICUs participating in this survey had policies to change their CVC infusion tubing in 3-4 days, and recent high-level evidence supports an update to extend this to 7 days. There remains work to be done to spread this evidence to ANZ ICUs and improve environmental sustainability initiatives.

Complications associated with prone positioning in mechanically ventilated COVID-19 patients: A multicentre, retrospective observational study.

BACKGROUND AND AIMS: Prone positioning is commonly applied to improve gas exchange in mechanically ventilated patients with coronavirus disease 2019 (COVID-19)-related acute respiratory distress syndrome (ARDS). Whilst prone positioning is effective, specific complications may arise. We aimed to assess the prevalence of specific complications related to prone positioning in patients mechanically ventilated for COVID-19-related ARDS. DESIGN: Multicentre, retrospective observational study. METHODS: Multi-centre observational study of mechanically ventilated patients with COVID-19-related ARDS admitted to intensive care units in Melbourne, Australia, from August to November 2021. Data on baseline characteristics, prone positioning, complications, and patient outcomes were collected. RESULTS: We assessed 553 prone episodes in 220 patients across seven sites (mean ± standard deviation age: 54 ± 13 years, 61% male). Overall, 58% (127/220) of patients experienced at least one prone-positioning-related complication. Pressure injury was the most prevalent (n = 92/220, 42%) complication reported. Factors associated with increased risk of pressure injury were male sex (adjusted odds ratio = 1.15, 95% confidence interval: [1.02-1.31]) and the total number of prone episodes (adjusted odds ratio = 1.11, 95% confidence interval: [1.07-1.15]). Device dislodgement was the next most common complication, occurring in 28 of 220 (13%) patients. There were no nerve or retinal injuries reported. CONCLUSIONS: Pressure injuries and line dislodgement were the most prevalent complications associated with prone positioning of patients mechanically ventilated for COVID-19. The risk of pressure injuries was associated with male sex and the number of prone positioning episodes.

Implementation approaches to improve environmental sustainability in operating theatres: a systematic review.

Operating theatres consume large amounts of energy and consumables and produce large amounts of waste. There is an increasing evidence base for reducing the climate impacts of healthcare that could be enacted into routine practice; yet, healthcare-associated emissions increase annually. Implementation science aims to improve the systematic uptake of evidence-based care into practice and could, therefore, assist in addressing the environmental impacts of healthcare. The aim of this systematic search with narrative synthesis was to explore what implementation approaches have been applied to reduce the environmental impact of operating theatre activities, described by implementation phases and methodologies. A search was conducted in EMBASE, PubMed, and CINAHL, limited to English and publication since 2010. In total, 3886 articles were retrieved and 11 were included. All were in the exploratory phase (seven of 11) or initial implementation phase (four of 11), but none were in the installation or full implementation phase. Three studies utilised a recognised implementation theory, model, or framework in the design. Four studies used interprofessional education to influence individuals' behaviour to reduce waste, improve waste segregation, or reduce anaesthetic gases. Of those that utilised behaviour change interventions, all were qualitatively successful in achieving environmental improvement. There was an absence of evidence for sustained effects in the intervention studies and little follow-up from studies that explored barriers to innovation. This review demonstrates a gap between evidence for reducing environmental impacts and uptake of proposed practice changes to deliver low-carbon healthcare. Future research into 'greening' healthcare should use implementation research methods to establish a solid implementation evidence base. SYSTEMATIC REVIEW PROTOCOL: PROSPERO CRD42022342786.

Nitrous Oxide Use in Australian Health Care: Strategies to Reduce the Climate Impact.

Nitrous oxide is a useful inhaled analgesic. Due to its high global warming potential and ozone-depleting properties, the nitrous oxide emissions related to health care are being increasingly scrutinized. In this narrative review, we will discuss the clinical uses of nitrous oxide relevant to anesthetists, in addition to its contribution as a greenhouse gas. Using available data from Australia, we will explore potential strategies for reducing the impact of those emissions, which are likely to be applicable in other countries. These include destruction of captured nitrous oxide, minimizing nitrous oxide waste and reducing clinical use. Anesthesia clinicians are well placed to raise awareness with colleagues and consumers regarding the environmental impact of nitrous oxide and to promote cleaner alternatives. Reducing use is likely to be the most promising reduction strategy without large-scale changes to infrastructure and subsequent delay in action.

Carbon emissions and hospital pathology stewardship: a retrospective cohort analysis.

BACKGROUND: As healthcare is responsible for 7% of Australia's carbon emissions, it was recognised that a policy implemented at St George Hospital, Sydney, to reduce non-urgent pathology testing to 2 days per week and, on other days only if essential, would also result in a reduction in carbon emissions. The aim of the study was to measure the impact of this intervention on pathology collections and associated carbon emissions and pathology costs. AIMS: To measure the impact of an intervention to reduce unnecessary testing on pathology collections and associated carbon emissions and pathology costs. METHODS: The difference in the number of pathology collections, carbon dioxide equivalents (CO2 e) for five common blood tests and pathology cost per admission were compared between a 6-month reference period and 6-month intervention period. CO2 e were estimated from published pathology CO2 e impacts. Cost was derived from pathology billing records. Outcomes were modelled using multivariable negative binomial, generalised linear and logistic regression. RESULTS: In total, 24 585 pathology collections in 5695 patients were identified. In adjusted analysis, the rate of collections was lower during the intervention period (rate ratio 0.90; 95% confidence interval (CI), 0.86-0.95; P < 0.001). This resulted in a reduction of 53 g CO2 e (95% CI, 24-83 g; P < 0.001) and $22 (95% CI, $9-$34; P = 0.001) in pathology fees per admission. The intervention was estimated to have saved 132 kg CO2 e (95% CI, 59-205 kg) and $53 573 (95% CI, 22 076-85 096). CONCLUSIONS: Reduction in unnecessary hospital pathology collections was associated with both carbon emission and cost savings. Pathology stewardship warrants further study as a potentially scalable, cost-effective and incentivising pathway to lowering healthcare associated greenhouse gas emissions.

Behavioural change interventions encouraging clinicians to reduce carbon emissions in clinical activity: a systematic review.

BACKGROUND: Clinical activity accounts for 70-80% of the carbon footprint of healthcare. A critical component of reducing emissions is shifting clinical behaviour towards reducing, avoiding, or replacing carbon-intensive healthcare. The objective of this systematic review was to find, map and assess behaviour change interventions that have been implemented in healthcare settings to encourage clinicians to reduce greenhouse gas emissions from their clinical activity. METHODS: Studies eligible for inclusion were those reporting on a behaviour change intervention to reduce carbon emissions via changes in healthcare workplace behaviour. Six databases were searched in November 2021 (updated February 2022). A pre-determined template was used to extract data from the studies, and risk of bias was assessed. The behaviour change techniques (BCTs) used in the interventions were coded using the BCT Taxonomy. RESULTS: Six full-text studies were included in this review, and 14 conference abstracts. All studies used a before-after intervention design. The majority were UK studies (n = 15), followed by US (n = 3) and Australia (n = 2). Of the full-text studies, four focused on reducing the emissions associated with anaesthesia, and two aimed at reducing unnecessary test ordering. Of the conference abstracts, 13 focused on anaesthetic gas usage, and one on respiratory inhalers. The most common BCTs used were social support, salience of consequences, restructuring the physical environment, prompts and cues, feedback on outcome of behaviour, and information about environmental consequences. All studies reported success of their interventions in reducing carbon emissions, prescribing, ordering, and financial costs; however, only two studies reported the magnitude and significance of their intervention's success. All studies scored at least one item as unclear or at risk of bias. CONCLUSION: Most interventions to date have targeted anaesthesia or pathology test ordering in hospital settings. Due to the diverse study outcomes and consequent inability to pool the results, this review is descriptive only, limiting our ability to conclude the effectiveness of interventions. Multiple BCTs were used in each study but these were not compared, evaluated, or used systematically. All studies lacked rigour in study design and measurement of outcomes. REVIEW REGISTRATION: The study was registered on Prospero (ID number CRD42021272526) (Breth-Petersen et al., Prospero 2021: CRD42021272526).

Aerosol Generation During High Intensity Exercise-Implications for COVID-19 Transmission.

BACKGROUND AND AIM: COVID-19 can be transmitted through aerosolised respiratory particles. The degree to which exercise enhances aerosol production has not been previously assessed. We aimed to quantify the size and concentration of aerosol particles and evaluate the impact of physical distance and surgical mask wearing during high intensity exercise (HIE). METHODS: Using a prospective observational crossover study, three healthy volunteers performed high intensity cardiopulmonary exercise testing at 80% of peak capacity in repeated 5-minute bouts on a cycle ergometer. Aerosol size and concentration was measured at 35, 150 and 300 cm from the participants in an anterior and lateral direction, with and without a surgical face mask, using an Aerodynamic Particle Sizer (APS) and a Mini Wide Range Aerosol Spectrometer (MiniWRAS), with over 10,000 sample points. RESULTS: High intensity exercise generates aerosol in the 0.2-1 micrometre range. Increasing distance from the rider reduces aerosol concentrations measured by both MiniWRAS (p=0.003 for interaction) and APS (p=0.041). However, aerosol concentrations remained significantly increased above baseline measures at 300 cm from the rider. A surgical face mask reduced submicron aerosol concentrations measured anteriorly to the rider (p=0.031 for interaction) but not when measured laterally (p=0.64 for interaction). CONCLUSIONS: High intensity exercise is an aerosol generating activity. Significant concentrations of aerosol particles are measurable well beyond the commonly recommended 150 cm of physical distancing. A surgical face mask reduces aerosol concentration anteriorly but not laterally to an exercising individual. Measures for safer exercise should emphasise distance and airflow and not rely solely on mask wearing.

Economic evaluations for intensive care unit randomised clinical trials in Australia and New Zealand: Practical recommendations for researchers.

OBJECTIVES: Economic evaluations of intensive care unit (ICU) interventions have specific considerations, including how to cost ICU stays and accurately measure quality of life in survivors. The aim of this article was to develop best practice recommendations for economic evaluations alongside future ICU randomised controlled trials (RCTs). REVIEW METHODS: We collated our experience based on expert consensus across several recent economic evaluations to provide best-practice, practical recommendations for researchers conducting economic evaluations alongside RCTs in the ICU. Recommendations were structured according to the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) Consolidated Health Economic Evaluation Reporting Standards (CHEERS) Task Force Report. RESULTS: We discuss recommendations across the components of economic evaluations, including: types of economic evaluation, the population and sample size, study perspective, comparators, time horizon, choice of health outcomes, measurement of effectiveness, measurement and valuation of quality of life, estimating resources and costs, analytical methods, and the increment cost-effectiveness ratio. We also provide future directions for research with regard to developing more robust economic evaluations for the ICU. CONCLUSION: Economic evaluations should be built alongside ICU RCTs and should be designed a priori using appropriate follow-up and data collection to capture patient-relevant outcomes. Further work is needed to improve the quality of data available for linkage in Australia as well as developing costing methods for the ICU and appropriate quality of life measurements.

A prospective clinical evaluation of a patient isolation hood during the COVID-19 pandemic.

BACKGROUND: Healthcare workers (HCWs) have frequently become infected with severe acute respiratory syndrome coronavirus 2 whilst treating patients with coronavirus disease 2019 (COVID-19). A variety of novel devices have been proposed to reduce COVID-19 cross-contamination. OBJECTIVES: The aim of the study was (i) to test whether patients and HCWs thought that a novel patient isolation hood was safe and comfortable and (ii) to obtain COVID-19 infection data of hospital HCWs. METHODS: This is a prospective cohort study of 20 patients, entailing HCW/patient questionnaires and safety aspects of prototype isolation hoods. COVID-19 data of HCWs were prospectively collected. Assessment of the hood's safety and practicality and adverse event reporting was carried out. OUTCOME MEASURES: The outcome measures are as follows: questionnaire responses, adverse event reporting, rates of infections in HCWs during the study period (20/6/2020 to 21/7/2020), and COVID-19 infections in HCWs reported until the last recorded diagnosis of COVID-19 in HCWs (20/6/2020 to 27/9/2020). RESULTS: Of the 64 eligible individual HCW surveys, 60 surveys were overall favourable (>75% questions answered in favour of the isolation hood). HCWs were unanimous in perceiving the hood as safe (60/60), preferring its use (56/56), and understanding its potential COVID-19 cross-contamination minimisation (60/60). All eight patients who completed the questionnaire thought the isolation hood helped prevent COVID-19 cross infection and was safe and comfortable. There were no reported patient safety adverse events. The COVID-19 attack rate from 20/6/2020 to 27/9/2020 among registered nurses was as follows: intensive care units (ICUs), 2.2% (3/138); geriatric wards, 13.2% (26/197); and COVID-19 wards, 18.3% (32/175). The COVID-19 attack rate among medical staff was as follows: junior staff, 2.1% (24/932); senior staff, 0.7% (4/607); aged care/rehabilitation, 6.7% (2/30); and all ICU medical staff, 8.6% (3/35). CONCLUSIONS: The isolation hood was preferred to standard care by HCWs and well tolerated by patients, and after the study, isolation hoods became part of standard ICU therapy. There was an association between being an ICU nurse and a low COVID-19 infection rate (no causality implied). ICU HCWs feel safer when treating patients with COVID-19 using an isolation hood.

Carbon Footprint of General, Regional, and Combined Anesthesia for Total Knee Replacements.

BACKGROUND: Health care itself contributes to climate change. Anesthesia is a "carbon hotspot," yet few data exist to compare anesthetic choices. The authors examined the carbon dioxide equivalent emissions associated with general anesthesia, spinal anesthesia, and combined (general and spinal anesthesia) during a total knee replacement. METHODS: A prospective life cycle assessment of 10 patients in each of three groups undergoing knee replacements was conducted in Melbourne, Australia. The authors collected input data for anesthetic items, gases, and drugs, and electricity for patient warming and anesthetic machine. Sevoflurane or propofol was used for general anesthesia. Life cycle assessment software was used to convert inputs to their carbon footprint (in kilogram carbon dioxide equivalent emissions), with modeled international comparisons. RESULTS: Twenty-nine patients were studied. The carbon dioxide equivalent emissions for general anesthesia were an average 14.9 (95% CI, 9.7 to 22.5) kg carbon dioxide equivalent emissions; spinal anesthesia, 16.9 (95% CI, 13.2 to 20.5) kg carbon dioxide equivalent; and for combined anesthesia, 18.5 (95% CI, 12.5 to 27.3) kg carbon dioxide equivalent. Major sources of carbon dioxide equivalent emissions across all approaches were as follows: electricity for the patient air warmer (average at least 2.5 kg carbon dioxide equivalent [20% total]), single-use items, 3.6 (general anesthesia), 3.4 (spinal), and 4.3 (combined) kg carbon dioxide equivalent emissions, respectively (approximately 25% total). For the general anesthesia and combined groups, sevoflurane contributed an average 4.7 kg carbon dioxide equivalent (35% total) and 3.1 kg carbon dioxide equivalent (19%), respectively. For spinal and combined, washing and sterilizing reusable items contributed 4.5 kg carbon dioxide equivalent (29% total) and 4.1 kg carbon dioxide equivalent (24%) emissions, respectively. Oxygen use was important to the spinal anesthetic carbon footprint (2.8 kg carbon dioxide equivalent, 18%). Modeling showed that intercountry carbon dioxide equivalent emission variability was less than intragroup variability (minimum/maximum). CONCLUSIONS: All anesthetic approaches had similar carbon footprints (desflurane and nitrous oxide were not used for general anesthesia). Rather than spinal being a default low carbon approach, several choices determine the final carbon footprint: using low-flow anesthesia/total intravenous anesthesia, reducing single-use plastics, reducing oxygen flows, and collaborating with engineers to augment energy efficiency/renewable electricity.

Recovery of Sevoflurane Anesthetic Gas Using an Organosilica Membrane in Conjunction with a Scavenging System.

Approximately 95% of the anesthetic gas administered to a patient is exhaled and ultimately released into the atmosphere. Most anesthetic gases have high global warming potential and so this approach adds significantly to the global greenhouse gas footprint. In this work, we develop a feasible means to capture such an anesthetic gas (sevoflurane) before it is released to the hospital scavenging system so that it is retained within the anesthetic circuit. Sevoflurane is retained using a microporous 1,2-bis(triethoxysilyl)ethane (BTESE) membrane prepared by a sol-gel method. The use of a ceramic membrane facilitates sanitization at high temperatures. A rapid thermal processing (RTP) technique is employed to reduce production time and to create a looser organosilica network, resulting in higher gas permeances, compared with the membrane synthesized from conventional thermal processing. The RTP membrane shows a slight decline in gas permeance when used with a dry mixture of CO2/N2/sevoflurane. This permeance falls again under 20% relative humidity feed conditions but the CO2/sevoflurane selectivity increases. The membrane performance shows little variation when the relative humidity is further increased. These promising results demonstrate that this microporous BTESE membrane has great potential for the recovery of sevoflurane in an anesthetic application.

Optimising a targeted test reduction intervention for patients admitted to the intensive care unit: The Targeted Intensive Care Test Ordering Cluster Trial intervention.

BACKGROUND: Approaches to routine diagnostic testing in the intensive care unit include time-scheduled testing and targeted testing. Blood tests and chest radiographs requested on a routine, time-scheduled basis may reduce the risk of missing important findings. Targeted testing, considering individual patient needs, may reduce unnecessary testing, wasted clinician time, and costs. However, existing evidence of targeted testing interventions is generally of low quality, and the optimal testing approach is uncertain. OBJECTIVES: The aim of the study was to describe the development of an intervention to reduce unnecessary diagnostic test ordering by clinicians working in intensive care, with the aim of informing the design of a pivotal clinical trial. METHODS: The Capability, Opportunity, Motivation-Behaviour model was used as a theoretical framework for change. The intervention components were informed by systematically identifying, assessing, and classifying targeted testing interventions in behavioural terms. Feedback from intensive care clinicians and patients was sought using surveys and a consumer reference group. RESULTS: The mean percentage of routine tests considered unnecessary by 201 intensive care clinicians was 33 (standard deviation = 16). When presented with a statement of the pros and cons for targeted versus liberal testing (n = 154), 93 (60%) consumer survey respondents preferred a more liberal approach, 33 (21%) preferred a more restrictive approach, and 28 (18%) were unsure. There were 24 behavioural interventions identified and incorporated into the final intervention. This had five major components: (i) a management committee to acquire, disseminate, and coordinate intervention-related information, (ii) a targeted testing guideline for sites, (iii) educational material for sites, (iv) site medical and nursing champions, and (v) site audit and feedback. CONCLUSIONS: Although surveyed intensive care clinicians report substantial unnecessary routine diagnostic testing, on the basis of currently available evidence, consumers prefer a more liberal approach. This feedback, and a framework to identify behavioural interventions, has been used to inform the design of a proposed targeted testing clinical trial.

The Effect of Sterically Active Ligand Substituents on Gas Adsorption within a Family of 3D Zn-Based Coordination Polymers.

An investigation of the adsorption properties of two structurally related, 3D coordination polymers of composition Zn(2-Mehba) and Zn(2,6-Me2hba) (2-Mehba = the dianion of 2-methyl-4-hydroxybenzoic acid and 2,6-Me2hba = the dianion of 2,6-dimethyl-4-hydroxybenzoic acid) is presented. A common feature of these structures are parallel channels that are able to accommodate appropriately sized guest molecules. The structures differ with respect to the steric congestion within the channels arising from methyl groups appended to the bridging ligands of the network. The host network, Zn(2-Mehba), is able to take up appreciable quantities of H2 (77 K) and CO2 and CH4 (298 K) in a reversible manner. In regard to the adsorption of N2 by Zn(2-Mehba), there appears to be an unusual temperature dependence for the uptake of the gas such that when the temperature is increased from 77 to 298 K the uptake of N2 increases. The relatively narrow channels of Zn(2,6-Me2hba) are too small to allow the uptake of N2 and CH4, but H2 molecules can be adsorbed. A pronounced step at elevated pressures in CO2 and N2O isotherms for Zn(2,6-Me2hba) is noted. Calculations indicate that rotation of phenolate rings leads to a change in the available intraframework space during CO2 dosing.

The carbon footprint of pathology testing.

OBJECTIVES: To estimate the carbon footprint of five common hospital pathology tests: full blood examination; urea and electrolyte levels; coagulation profile; C-reactive protein concentration; and arterial blood gases. DESIGN, SETTING: Prospective life cycle assessment of five pathology tests in two university-affiliated health services in Melbourne. We included all consumables and associated waste for venepuncture and laboratory analyses, and electricity and water use for laboratory analyses. MAIN OUTCOME MEASURE: Greenhouse gas footprint, measured in carbon dioxide equivalent (CO2 e) emissions. RESULTS: CO2 e emissions for haematology tests were 82 g/test (95% CI, 73-91 g/test) for coagulation profile and 116 g/test (95% CI, 101-135 g/test) for full blood examination. CO2 e emissions for biochemical tests were 0.5 g/test CO2 e (95% CI, 0.4-0.6 g/test) for C-reactive protein (low because typically ordered with urea and electrolyte assessment), 49 g/test (95% CI, 45-53 g/test) for arterial blood gas assessment, and 99 g/test (95% CI, 84-113 g/test) for urea and electrolyte assessment. Most CO2 e emissions were associated with sample collection (range, 60% for full blood examination to 95% for coagulation profile); emissions attributable to laboratory reagents and power use were much smaller. CONCLUSION: The carbon footprint of common pathology tests was dominated by those of sample collection and phlebotomy. Although the carbon footprints were small, millions of tests are performed each year in Australia, and reducing unnecessary testing will be the most effective approach to reducing the carbon footprint of pathology. Together with the detrimental health and economic effects of unnecessary testing, our environmental findings should further motivate clinicians to test wisely.

Environmental sustainability in anaesthesia and critical care.

The detrimental health effects of climate change continue to increase. Although health systems respond to this disease burden, healthcare itself pollutes the atmosphere, land, and waterways. We surveyed the 'state of the art' environmental sustainability research in anaesthesia and critical care, addressing why it matters, what is known, and ideas for future work. Focus is placed upon the atmospheric chemistry of the anaesthetic gases, recent work clarifying their relative global warming potentials, and progress in waste anaesthetic gas treatment. Life cycle assessment (LCA; i.e. 'cradle to grave' analysis) is introduced as the definitive method used to compare and contrast ecological footprints of products, processes, and systems. The number of LCAs within medicine has gone from rare to an established body of knowledge in the past decade that can inform doctors of the relative ecological merits of different techniques. LCAs with practical outcomes are explored, such as the carbon footprint of reusable vs single-use anaesthetic devices (e.g. drug trays, laryngoscope blades, and handles), and the carbon footprint of treating an ICU patient with septic shock. Avoid, reduce, reuse, recycle, and reprocess are then explored. Moving beyond routine clinical care, the vital influences that the source of energy (renewables vs fossil fuels) and energy efficiency have in healthcare's ecological footprint are highlighted. Discussion of the integral roles of research translation, education, and advocacy in driving the perioperative and critical care environmental sustainability agenda completes this review.