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Hypoxic blackwater events occur worldwide, affecting inland and coastal waters. These events have been exacerbated by man‐made floodplain drainage, leading to large‐scale fish kills and ecological degradation. This paper presents a new method to identify estuarine catchment areas that are most likely to generate hypoxic conditions. The method uses established risk factors, including vegetation type, inundation extent and duration, ground‐truthed in eastern Australia. A catchment is at higher risk of hypoxic blackwater generation if (a) it is located where floodwaters are high and/or drainage is impeded, (b) the site topography includes an extensive, low‐lying floodplain; and/or (c) the land‐use and environmental characteristics have a high deoxygenation potential. Consequent impacts to an estuary are determined by the floodplain connectivity with the estuary, and the discharge characteristics of the catchment drainage system. Where multiple, proximate catchments have similar drainage conditions, compounding plumes of hypoxic blackwater can overwhelm the assimilation capacity of the estuary. Climate change may significantly increase the volume and frequency of blackwater events in estuarine environments as a result of reduced drainage due to sea level rise, higher temperatures, and more intense and sporadic rainfall events. It is recommended that management measures be introduced to mitigate the effects of climate change and avoid further widespread hypoxic blackwater events. Key Points: A methodology is presented to differentiate estuarine catchments by their potential to generate hypoxic blackwater eventsLocal topographic and hydrodynamic conditions strongly influence the potential volume of hypoxic blackwater generated over a catchmentClimate change may increase the frequency and severity and change the distribution of blackwater risk throughout an estuary [ABSTRACT FROM AUTHOR]

Background: Functional capacity, as measured by the 6-min walk test (6MWT), is often reduced in fibrotic interstitial lung disease (ILD). This study evaluated longitudinal changes and the prognostic significance of 6MWT parameters, and explored change in oxygenation status as a physiological criterion to define disease progression in patients with fibrotic ILD.Research Questions: What are the trajectories and prognostic value of 6MWT parameters in patients with fibrotic ILD?Study Design and Methods: Using prospective registries in Australia and Canada, patients with idiopathic pulmonary fibrosis (IPF) and non-IPF fibrotic ILD were stratified by the presence of criteria for progressive pulmonary fibrosis (PPF). The cumulative incidence of exertional and resting hypoxemia and changes in 6-min walk distance (6MWD) and composite indices (distance-saturation product and distance-saturation-oxygen product) were determined, with prognostic significance evaluated at the time of meeting criteria for PPF. New-onset exertional or resting hypoxemia was evaluated as another potential criterion for PPF.Results: Patients with IPF/PPF (n = 126) and non-IPF/PPF (n = 227) had a similar cumulative incidence of exertional hypoxemia and annualized decline in 6MWD and composite indices, which varied across each PPF criterion. Patients with IPF/non-PPF (n = 231) and non-IPF/non-PPF (n = 531) had a significantly lower incidence of hypoxemia than those with IPF/PPF, with an annualized increase in 6MWD and composite indices in the non-IPF/non-PPF group. Exertional or resting hypoxemia at the time of meeting criteria for PPF was independently associated with reduced transplant-free survival in IPF and non-IPF, adjusting for patient demographics and lung function. Adding new-onset exertional or resting hypoxemia as a physiological criterion reduced the median time to development of PPF from 11.2 to 6.7 months in IPF and from 11.7 to 5.6 months in non-IPF in patients who eventually met both definitions (P < .001 for both).Interpretation: Patients with IPF/PPF and non-IPF/PPF have comparable deterioration in functional capacity. Oxygenation status provides prognostic information in PPF and may assist in defining disease progression in fibrotic ILD. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the acute performance and physiological responses, with specific reference to muscle oxygenation, to ambient air temperature manipulation during repeated-sprint training in hypoxia (RSH). Thirteen male team-sport players completed one familiarisation and three experimental sessions at a simulated altitude of ∼3000 m (FIO2 0.144). Air temperatures utilised across the three experimental sessions were: 20°C, 35°C and 40°C (all 50% relative humidity). Participants performed 3 × 5 × 10-s maximal cycle sprints, with 20-s passive recovery between sprints, and 5 min active recovery between sets. There were no differences between conditions for cycling peak power, mean power, and total work (p>0.05). Peak core temperature (Tc) was not different between conditions (38.11 ± 0.36°C). Vastus lateralis muscle deoxygenation during exercise and reoxygenation during recovery was of greater magnitude in 35°C and 40°C than 20°C (p<0.001 for all). There was no condition × time interaction for Tc, skin temperature, pulse oxygen saturation, heart rate, rating of perceived exertion and thermal sensation (P>0.05). Exercise-induced increases in blood lactate concentration were higher in 35°C and 40°C than 20°C (p=0.010 and p=0.001, respectively). Integrating ambient temperatures up to 40°C into a typical RSH session had no detrimental effect on performance. Additionally, the augmented muscle oxygenation changes experienced during exercise and recovery in temperatures ≥35°C may indicate that the potency of RSH training is increased with additional heat. However, alterations to the training session may be required to generate a sufficient rise in Tc for heat training purposes. Highlights Heat exposure (35-40°C) did not affect mechanical performance during a typical RSH session. This indicates hot ambient temperature can be implemented during RSH, without negative consequence to training output. Hotter ambient conditions (35-40°C) likely result in greater muscle oxygenation changes during both exercise and recovery compared to temperate conditions. Although hotter sessions were perceived as more difficult and more thermally challenging, they did not further elevate Tc beyond that of temperate conditions. Accordingly, if intended to be used for heat acclimation purposes, alterations to the session may be required to increase heat load. [ABSTRACT FROM AUTHOR]

Objective: In 2013, our intubations highlighted a safety gap – only 49% achieved first‐pass success without hypoxia or hypotension. NAP4 recommended debriefing after intubation, but limited published methods existed. Primary aim is to implement a feasible process for immediate debriefing and feedback for emergency airway management. Secondary aims are to contribute to reduced frequency of adverse intubation‐related events and implement qualitative improvements in patient safety through team reflection and feedback. Methods: A component of a prospective quality improvement (QI) study over 4 years in the ED of the Royal Children's Hospital, Melbourne, Australia. Debrief and feedback after intubation was one of seven study interventions. Targeted staff training and involvement of departmental leaders occurred. A post‐intervention cohort was audited in 2016. Analysis included the Team Emergency Assessment Measure. Results: Immediate post‐event debriefing occurred in 39 (85%) of 46 intubations. Debriefing was short (median duration 5 min, interquartile range [IQR] 5–10) and soon after (median time 20 min, IQR 5–60). Commonest location was the resuscitation room (92%), led by the team leader (97%). Commonest barrier preventing immediate debriefing was excessive workload. Two QI process measures were assessed during debriefing (adequate resuscitation, airway plan) and case summaries distributed for 100% of intubations. Performance outcomes included contribution to 78% first‐pass success without hypoxia or hypotension. Team reflection prompted changes to environment (signage, stickers), training (skill drills), teamwork and process (communication, clinical event debriefing). Conclusion: Structured and targeted debriefing after intubating children in the ED is feasible and contributes to measurable and qualitative improvements in patient safety. [ABSTRACT FROM AUTHOR]

Objective: In response to COVID‐19, we introduced and examined the effect of a raft of modifications to standard practice on adverse events and first‐attempt success (FAS) associated with ED intubation. Methods: An analysis of prospectively collected registry data of all ED intubations over a 3‐year period at an Australian Major Trauma Centre. During the first 6 months of the COVID‐19 pandemic in Australia, we introduced modifications to standard practice to reduce the risk to staff including: aerosolisation reduction, comprehensive personal protective equipment for all intubations, regular low fidelity simulation with 'sign‐off' for all medical and nursing staff, senior clinician laryngoscopist and the introduction of pre‐drawn medications. Results: There were 783 patients, 136 in the COVID‐19 era and 647 in the pre‐COVID‐19 comparator group. The rate of hypoxia was higher during the COVID‐19 era compared to pre‐COVID‐19 (18.4% vs 9.6%, P < 0.005). This occurred despite the FAS rate remaining very high (95.6% vs 93.8%, P = 0.42) and intubation being undertaken by more senior laryngoscopists (consultant 55.9% during COVID‐19 vs 22.6% pre‐COVID‐19, P < 0.001). Other adverse events were similar before and during COVID‐19 (hypotension 12.5% vs 7.9%, P = 0.082; bradycardia 1.5% vs 0.5%, P = 0.21). Video laryngoscopy was more likely to be used during COVID‐19 (95.6% vs 82.5%, P < 0.001) and induction of anaesthesia more often used ketamine (66.9% vs 42.3%, P < 0.001) and rocuronium (86.8% vs 52.1%, P < 0.001). Conclusions: This raft of modifications to ED intubation was associated with significant increase in hypoxia despite a very high FAS rate and more senior first laryngoscopist. [ABSTRACT FROM AUTHOR]

The sterile insect technique (SIT), a benign pest control strategy, is currently undergoing a substantial renewal for controlling the Queensland fruit fly (Q-fly), a major horticultural pest in Australia. Production and delivery of high-quality flies is fundamental to effective SIT. While efforts are commonly made to improve production at a factory level (both quantity and quality), the methods and conditions during post-production operations also need to be tuned to minimize reductions in fly quality. Hypoxia, irradiation and vibration are important stressors that are experienced by pupae during production, packing and transportation. However, little is known about the impacts of such stressors on Q-fly quality. We conducted two laboratory experiments to investigate the response of Q-fly to such post-production stressors, with the aim of then developing guidelines that minimize quality reductions for SIT programs. In Experiment 1, Q-fly pupae of different ages (3, 6 or 9-day old) were exposed to vibrations for 5, 30, 60 and 300 s. Flight ability tests revealed that 6- and 9-day-old pupae were the most sensitive to vibration, with significant reduction in emergence and percentage of fliers. In Experiment 2, the effect of hypoxia, irradiation and vibration, in isolation or in combination, was evaluated on 9-day-old pupae. Irradiation and vibration exhibited a multiplicative negative effect on flight ability parameters. It is recommended not to subject pupae to intense or extensive vibration during the late pupal stage and to avoid prolonged periods of hypoxia. [ABSTRACT FROM AUTHOR]

Objectives: To describe the epidemiology, clinical practice and outcomes of paediatric ED intubation in Australia and New Zealand. Method: Prospectively collected airway management audit data from 43 EDs in Australia and New Zealand that was submitted to the Australia and New Zealand Emergency Department Airway Registry between 2010 and 2015. Results: Paediatric cases accounted for 4.94% (270/5463) of cases (median age = 3, interquartile range [IQR] = 2–9). A median of 5 (IQR = 2–9) intubations were reported per department per year. Most intubations were performed for medical indications (72.2%), including seizure (25.2%) and respiratory failure (15.2%). Patients were physiologically compromised prior to intubation with 69.5% comatose, 50.9% outside of the normal age‐adjusted range for respiratory rate, 15.9% hypoxic and 12.6% hypotensive. Complication rate was 33.3% and desaturation was the most common (18.5%). The ED mortality rate was 3.8%. First pass success (FPS) was 80% (95% CI 75.2–84.8). Infants less than 1 year of age had lower FPS, higher rates of difficult laryngoscopy and higher rates of desaturation than other age groups. Conclusion: Paediatric intubation in Australasian EDs is rare from a departmental and individual provider viewpoint. Success rates are similar to contemporary international registries. Complications are common and ongoing collaborative multicentre audit with resultant quality improvement is desirable to facilitate improved success and reduced complications. [ABSTRACT FROM AUTHOR]

Purpose: To quantify physiological and performance effects of hypoxic exposure, a training camp, the placebo effect, and a combination of these factors. Methods: Elite Australian and International race walkers (n = 17) were recruited, including men and women. Three groups were assigned: 1) Live High:Train Low (LHTL, n = 6) of 14 h/d at 3000 m simulated altitude; 2) Placebo (n = 6) of 14 h/d of normoxic exposure (600 m); and 3) Nocebo (n = 5) living in normoxia. All groups undertook similar training during the intervention. Physiological and performance measures included 10-min maximal treadmill distance, peak oxygen uptake (VO2peak), walking economy, and hemoglobin mass (Hbmass). Results: Blinding failed, so the Placebo group was a second control group aware of the treatment. All three groups improved treadmill performance by approx. 4%. Compared with Placebo, LHTL increased Hbmass by 8.6% (90% CI: 3.5 to 14.0%; P = .01, very likely), VO2peak by 2.7% (-2.2 to 7.9%; P = .34, possibly), but had no additional improvement in treadmill distance (-0.8%, -4.6 to 3.8%; P = .75, unlikely) or economy (-8.2%, -24.1 to 5.7%; P = .31, unlikely). Compared with Nocebo, LHTL increased Hbmass by 5.5% (2.5 to 8.7%; P = .01, very likely), VO2peak by 5.8% (2.3 to 9.4%; P = .02, very likely), but had no additional improvement in treadmill distance (0.3%, -1.9 to 2.5%; P = .75, possibly) and had a decrease in walking economy (-16.5%, -30.5 to 3.9%; P = .04, very likely). Conclusion: Overall, 3-wk LHTL simulated altitude training for 14 h/d increased Hbmass and VO2peak, but the improvement in treadmill performance was not greater than the training camp effect. [ABSTRACT FROM AUTHOR]

BACKGROUND: Exertional desaturation is an important predictor of mortality in patients with interstitial lung disease. We evaluated the prevalence of exertional desaturation in subjects with interstitial lung disease and determined its relationship with the prescription of ambulatory oxygen therapy. METHODS: Our retrospective analysis examined prospectively collected data from interstitial lung disease registries of 2 Melbourne hospitals: Alfred Health and Austin Health. All patients with baseline the 6-min walk tests on room air were included. We evaluated the prescription of ambulatory oxygen therapy, up to 3 months after 6-min walk tests, among those with exertional desaturation. RESULTS: Of the 400 subjects, 214 (54%) had exertional desaturation. The prevalence of desaturation increased with the severity of lung function impairment (FVC measurement: 33% for > 75% predicted, 69% for 50-75% predicted, 86% for < 50% predicted; diffusing capacity of the lung for carbon monoxide measurement: 20% for > 55% predicted, 64% for 36-55% predicted, 93% for ≤ 35% predicted, P < .001 for both severity classifications). There was no difference in the prevalence of exertional desaturation among common disease subtypes (P = .17). Among the desaturators, 14 (7%) had resting hypoxemia and all were prescribed long-term oxygen therapy. Of the remaining 200 with exertional desaturation only, 58 (29%) were prescribed ambulatory oxygen therapy. Multiple logistic regression showed independent associations between the ambulatory oxygen therapy prescription and shorter 6-min walk distance (P<.001) as well as worse FVC (% predicted, P = .037). CONCLUSIONS: Exertional desaturation is common in subjects with interstitial lung disease. More severely impaired exercise capacity and worse lung function are associated with the prescription of ambulatory oxygen therapy in interstitial lung disease. [ABSTRACT FROM AUTHOR]

Background: Hypoxemia and anemia are common findings in critically ill patients admitted to Intensive Care Units. Both are independently associated with significant morbidity and mortality. However, the interaction between oxygenation and anemia and their impact on mortality in critically ill patients has not been clearly defined. We undertook this study to determine whether hemoglobin (Hb) level would modify the association between hypoxemia and mortality in mechanically ventilated critically ill patients. Methods: We performed a retrospective cohort study of all mechanically ventilated adult patients (aged >16 years) in the Australian and New Zealand Intensive Care Society Adult Patient Database (APD) admitted over a 10-year period. Multivariate hierarchical logistic regression was used to assess the relationship between hypoxemia and hospital mortality stratified by Hb. Results: Of 1,196,089 patients in the APD, 219,723 satisfied our inclusion and exclusion criteria. There was a linear negative relationship between hypoxemia and hospital mortality which was significantly modified when stratified by Hb. Hb independently increased the risk of mortality in patients with arterial oxygen tension <102. Conclusions: Hb is an effect modifier on the association between oxygenation and mortality. [ABSTRACT FROM AUTHOR]

Objective: Skin-to-skin care (SSC) has proven benefits in preterm infants, but increased hypoxic and bradycardic events have been reported. This may make clinicians hesitant to recommend SSC as standard care. We hypothesised that regional cerebral oxygenation (rStO2) measured with near infrared spectroscopy is not worse during SSC compared with standard incubator care.Design: Prospective, observational, non-inferiority study.Setting: Single tertiary perinatal centre in Australia.Patients: Forty preterm infants (median (IQR) 30.6 (29.1-31.7) weeks' gestation) not receiving respiratory support were studied on day 14 (8-38).Interventions: Recordings during 90 min of incubator care, followed by 90 min of SSC. Each infant acted as their own control and caregivers were blinded to the rStO2 measurements.Main Outcome Measures: The primary outcome was the mean difference in rStO2 between SSC and incubator care. The prespecified margin of non-inferiority was -1.5%. Secondary outcomes included heart rate (HR), peripheral oxygen saturation (SpO2), time in quiet sleep, temperature and hypoxic (SpO2 <80% for >5 s) or bradycardic events (HR <80 bpm for >5 s) and time spent in cerebral hypoxia (rStO2<55%) and hyperoxia (rStO2>85%).Results: Mean (SD) rStO2 was lower during SSC compared with incubator care: 73.6 (6.0)% vs 74.8 (4.6)%, mean difference (95% CI) 1.3 (2.2 to 0.4)%. HR was 5 bpm higher, SpO2 1% lower and time in quiet sleep 24% longer during SSC. Little evidence of a difference was observed in temperature. The number of hypoxic or bradycardic events as well as the proportion of time spent in cerebral hypoxia and hyperoxia was very low in both periods.Conclusions: Mean rStO2 was marginally lower during SSC without observed differences in hypoxic or bardycardic events but an increase in time spent in quiet sleep.Trial Registration Number: This trial is linked to Australian New Zealand Clinical Trials Registry: identifier 12616000240448. It was registered pre-results. [ABSTRACT FROM AUTHOR]

Objective: To determine the impact of a multidisciplinary fetal surveillance education program (FSEP) on term neonatal outcomes.Methods: A retrospective cohort study of term neonatal outcomes before (1998-2004) and after (2005-2010) introduction of a FSEP. Clinical data was collected for all term infants admitted to a neonatal intensive care unit (NICU) in Australia between 1998 and 2010. Infants with congenital abnormalities were excluded. Neonatal mortality and severe neonatal morbidity (admission to a NICU, respiratory support, hypoxic encephalopathy) were compared before and after the FSEP was introduced. The rates of operative delivery during this time were assessed.Results: There were 3 512 596 live term births between 1998 and 2010. The intrapartum hypoxic death rate at term decreased from 2.02 to 1.07 per 10 000 total births. More neonates were admitted to NICU after 2005 (10.6 versus 14.6 per 10 000 live births), however fewer babies admitted to the neonatal unit had Apgar scores < 5 at five minutes (55.1-45.5%, RR 0.82, 95% CI 0.7-0.87); and rates of hypoxic ischemic encephalopathy fell from 36% to 30% (RR 0.83, 95% CI 0.76-0.90). There was no increase in rates of emergency in labour caesarean sections (11.7% pre versus 11.1% post, RR 0.95, 95% CI 0.95-0.96).Conclusions: Introduction of a national FSEP was associated with increased neonatal admissions but a reduction in intrapartum hypoxia, without increasing emergency caesarean section rates. [ABSTRACT FROM AUTHOR]

Background: Amniotic fluid embolism (AFE) is a major cause of direct maternal mortality in Australia and New Zealand. There has been no national population study of AFE in either country. The aim of this study was to estimate the incidence of amniotic fluid embolism in Australia and New Zealand and to describe risk factors, management, and perinatal outcomes.Methods: A population-based descriptive study using the Australasian Maternity Outcomes Surveillance System (AMOSS) carried out in 263 eligible sites (>50 births per year) covering an estimated 96% of women giving birth in Australia and all 24 New Zealand maternity units (100% of women giving birth in hospitals) between January 1 2010-December 31 2011. A case of AFE was defined either as a clinical diagnosis (acute hypotension or cardiac arrest, acute hypoxia and coagulopathy in the absence of any other potential explanation for the symptoms and signs observed) or as a post mortem diagnosis (presence of fetal squames/debris in the pulmonary circulation).Results: Thirty-three cases of AFE were reported from an estimated cohort of 613,731women giving birth, with an estimated incidence of 5.4 cases per 100,000 women giving birth (95% CI 3.5 to 7.2 per 100,000). Two (6%) events occurred at home whilst 46% (n = 15) occurred in the birth suite and 46% (n = 15) in the operating theatre (location not reported in one case). Fourteen women (42%) underwent either an induction or augmentation of labour and 22 (67%) underwent a caesarean section. Eight women (24%) conceived using assisted reproduction technology. Thirteen (42%) women required cardiopulmonary resuscitation, 18% (n = 6) had a hysterectomy and 85% (n = 28) received a transfusion of blood or blood products. Twenty (61%) were admitted to an Intensive Care Unit (ICU), eight (24%) were admitted to a High Dependency Unit (HDU) and seven (21%) were transferred to another hospital for further management. Five woman died (case fatality rate 15%) giving an estimated maternal mortality rate due to AFE of 0.8 per 100,000 women giving birth (95% CI 0.1% to 1.5%). There were two deaths among 36 infants.Conclusions: A coordinated emergency response requiring resource intense multi-disciplinary input is required in the management of women with AFE. Although the case fatality rate is lower than in previously published studies, high rates of hysterectomy, resuscitation, and admission to higher care settings reflect the significant morbidity associated with AFE. Active, ongoing surveillance to document the risk factors and short and long-term outcomes of women and their babies following AFE may be helpful to guide best practice, management, counselling and service planning. A potential link between AFE and assisted reproductive technology warrants further investigation. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the study was to determine if oxygen delivered through humidified high flow nasal cannulae (HHFNC) reduced the need for escalation in ventilation management and work of breathing in the ED patients presenting with acute undif-ferentiated shortness of breath compared with standard oxygen therapy. Methods: This was an unblinded randomised control trial conducted at two hospital EDs in Sydney, Australia. Eligible patients presenting with shortness of breath were randomised to HHFNC or standard oxygen therapy. Primary outcomes were the need to escalate ventilation therapy or a reduction in respiratory rate of 20 % or more within 2 h of commencement. Results: One hundred patients were enrolled in the trial. The intervention group receiving HHFNC was associated with a higher proportion of patients with a reduced respiratory rate at 2 h (66.7% vs 38.5%, P = 0.005) and a lower proportion of patients requiring escalation in ventilation therapy (4.2% vs 19%, P = 0.02) compared with standard oxygen therapy. Conclusions: The use of high flow nasal cannula oxygenation was associated with improved respiratory state in selected patients presenting to the ED with acute undifferentiated shortness of breath. [ABSTRACT FROM AUTHOR]

The purpose of the Thoracic Society of Australia and New Zealand guidelines is to provide simple, practical evidence-based recommendations for the acute use of oxygen in adults in clinical practice. The intended users are all health professionals responsible for the administration and/or monitoring of oxygen therapy in the management of acute medical patients in the community and hospital settings (excluding perioperative and intensive care patients), those responsible for the training of such health professionals, and both public and private health care organizations that deliver oxygen therapy. [ABSTRACT FROM AUTHOR]

To assess the impact of ‘top-up' normoxic or hypoxic repeatsprint training on sea-level repeat-sprint ability, thirty team sport athletes were randomly split into three groups, which were matched in running repeat-sprint ability (RSA), cycling RSA and 20 m shuttle run performance. Two groups then performed 15 maximal cycling repeat-sprint training sessions over 5 weeks, in either normoxia (NORM) or hypoxia (HYP), while a third group acted as a control (CON). In the post-training cycling RSA test, both NORM (13.6%; p = 0.0001, and 8.6%; p = 0.001) and HYP (10.3%; p = 0.007, and 4.7%; p = 0.046) significantly improved overall mean and peak power output, respectively, whereas CON did not change (1.4%; p = 0.528, and - 1.1%; p = 0.571, respectively); with only NORM demonstrating a moderate effect for improved mean and peak power output compared to CON. Running RSA demonstrated no significant between group differences; however, the mean sprint times improved significantly from pre- to post-training for CON (1.1%), NORM (1.8%), and HYP (2.3%). Finally, there were no group differences in 20 m shuttle run performance. In conclusion, ‘top-up' training improved performance in a task-specific activity (i.e. cycling); however, there was no additional benefit of conducting this ‘top-up' training in hypoxia, since cycle RSA improved similarly in both HYP and NORM conditions. Regardless, the ‘top-up' training had no significant impact on running RSA, therefore the use of cycle repeat-sprint training should be discouraged for team sport athletes due to limitations in specificity. [ABSTRACT FROM AUTHOR]

Background and Objective: Hypoxic training techniques are increasingly used by athletes in an attempt to improve performance in normoxic environments. The 'live low-train high (LLTH)' model of hypoxic training may be of particular interest to athletes because LLTH protocols generally involve shorter hypoxic exposures (approximately two to five sessions per week of <3 h) than other traditional hypoxic training techniques (e.g. live high-train high or live high-train low). However, the methods employed in LLTH studies to date vary greatly with respect to exposure times, training intensities, training modalities, degrees of hypoxia and performance outcomes assessed. Whilst recent reviews provide some insight into how LLTH may be applied to enhance performance, little attention has been given to how training intensity/modality may specifically influence subsequent performance in normoxia. Therefore, this systematic review aims to evaluate the normoxic performance outcomes of the available LLTH literature, with a particular focus on training intensity and modality. Data Sources and Study Selection: A systematic search was conducted to capture all LLTH studies with a matched normoxic (control) training group and the assessment of performance under normoxic conditions. Studies were excluded if no training was completed during the hypoxic exposures, or if these exposures exceeded 3 h per day. Four electronic databases were searched (PubMed, SPORTDiscus™, EMBASE and Web of Science) during August 2013, and these searches were supplemented by additional manual searches until December 2013. Results: After the electronic and manual searches, 40 papers were deemed to meet the inclusion criteria, representing 31 separate studies. Within these 31 studies, four types of LLTH were identified: (1) continuous low-intensity training in hypoxia (CHT, n = 16), (2) interval hypoxic training (IHT, n = 4), (3) repeated sprint training in hypoxia (RSH, n = 3) and (4) resistance training in hypoxia (RTH, n = 4). Four studies also used a combination of CHT and IHT. The majority of studies reported no difference in normoxic performance between the hypoxic and normoxic training groups ( n = 19), while nine reported greater improvements in the hypoxic group and three reported poorer outcomes compared with the control group. Selection of training intensity (including matching relative or absolute intensity between normoxic and hypoxic groups) was identified as a key factor in mediating the subsequent normoxic performance outcomes. Five studies included some form of normoxic training for the hypoxic group and 14 studies assessed performance outcomes not specific to the training intensity/modality completed during the training intervention. Conclusion: Four modes of LLTH are identified in the current literature (CHT, IHT, RSH and RTH), with training mode and intensity appearing to be key factors in mediating subsequent performance responses in normoxia. Improvements in normoxic performance appear most likely following high-intensity, short-term and intermittent training (e.g. IHT, RSH). LLTH programmes should carefully apply the principles of training and testing specificity and include some high-intensity training in normoxia. For RTH, it is unclear whether the associated adaptations are greater than those of traditional (maximal) resistance training programmes. [ABSTRACT FROM AUTHOR]

Pulse oximetry provides a simple, non-invasive approximation of arterial oxygenation in a wide variety of clinical settings including emergency and critical-care medicine, hospital-based and ambulatory care, perioperative monitoring, inpatient and outpatient settings, and for specific diagnostic applications. Pulse oximetry is of utility in perinatal, paediatric, adult and geriatric populations but may require use of age-specific sensors in these groups. It plays a role in the monitoring and treatment of respiratory dysfunction by detecting hypoxaemia and is effective in guiding oxygen therapy in both adult and paediatric populations. Pulse oximetry does not provide information about the adequacy of ventilation or about precise arterial oxygenation, particularly when arterial oxygen levels are very high or very low. Arterial blood gas analysis is the gold standard in these settings. Pulse oximetry may be inaccurate as a marker of oxygenation in the presence of dyshaemoglobinaemias such as carbon monoxide poisoning or methaemoglobinaemia where arterial oxygen saturation values will be overestimated. Technical considerations such as sensor position, signal averaging time and data sampling rates may influence clinical interpretation of pulse oximetry readings. [ABSTRACT FROM AUTHOR]

Live High:Train Low (LHTL) altitude training is a popular ergogenic aid amongst athletes. An alternative hypoxia protocol, acute (60-90 min daily) Intermittent Hypoxic Exposure (IHE), has shown potential for improving athletic performance. The aim of this study was to compare directly the effects of LHTL and IHE on the running and blood characteristics of elite triathletes. Changes in total haemoglobin mass (Hbmass), maximal oxygen consumption (VO2max), velocity at VO2max (vVO2max), time to exhaustion (TTE), running economy, maximal blood lactate concentration ([La]) and 3 mM [La] running speed were compared following 17 days of LHTL (240 h of hypoxia), IHE (10.2 h of hypoxia) or Placebo treatment in 24 Australian National Team triathletes (7 female, 17 male). There was a clear 3.2 ± 4.8% (mean ± 90% confidence limits) increase in Hbmass following LHTL compared with Placebo, whereas the corresponding change of -1.4 ± 4.5% in IHE was unclear. Following LHTL, running economy was 2.8 ± 4.4% improved compared to IHE and 3mM [La] running speed was 4.4 ± 4.5% improved compared to Placebo. After IHE, there were no beneficial changes in running economy or 3mM [La] running speed compared to Placebo. There were no clear changes in VO2max, vVO2max and TTE following either method of hypoxia. The clear difference in Hbmass response between LHTL and IHE indicated that the dose of hypoxia in IHE was insufficient to induce accelerated erythropoiesis. Improved running economy and 3mM [La] running speed following LHTL suggested that this method of hypoxic exposure may enhance performance at submaximal running speeds. Overall, there was no evidence to support the use of IHE in elite triathletes. [ABSTRACT FROM AUTHOR]

The article discusses a study on paediatric hyperbaric oxygen therapy (HBOT) in Australia. The study involved patients treated at four hyperbaric medical units between January 1998 and December 2011. Some adverse events linked with HBOT therapy included middle ear barotraumas, progressive hypoxaemia and central nervous system oxygen toxicity. The study found that hyperbaric oxygen therapy in children is associated with low rates of complications.

Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O2-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in con- temporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes. [ABSTRACT FROM AUTHOR]

Abstract: Episodic hypoxic events can occur following summer floods in sub-tropical estuaries of eastern Australia. These events can cause deoxygenation of waterways and extensive fish mortality. Here, we present a conceptual model that links key landscape drivers and biogeochemical processes which contribute to post-flood hypoxic events. The model provides a framework for examining the nature of anthropogenic forcing. Modification of estuarine floodplain surface hydrology through the construction of extensive drainage networks emerges as a major contributing factor to increasing the frequency, magnitude and duration of hypoxic events. Forcing occurs in two main ways. Firstly, artificial drainage of backswamp wetlands initiates drier conditions which cause a shift in vegetation assemblages from wetland-dominant species to dryland-dominant species. These species, which currently dominate the floodplain, are largely intolerant of inundation and provide abundant labile substrate for decomposition following flood events. Decomposition of this labile carbon pool consumes oxygen in the overlying floodwaters, and results in anoxic conditions and waters with excess deoxygenation potential (DOP). Carbon metabolism can be strongly coupled with microbially-mediated reduction of accumulated Fe and Mn oxides, phases which are common on these coastal floodplain landscapes. Secondly, artificial drainage enhances discharge rates during the flood recession phase. Drains transport deoxygenated high DOP floodwaters rapidly from backswamp wetlands to the main river channel to further consume oxygen. This process effectively displaces the natural carbon metabolism processes from floodplain wetlands to the main channel. Management options to reduce the impacts of post-flood hypoxia include i) remodifying drainage on the floodplain to promote wetter conditions, thereby shifting vegetation assemblages towards inundation-tolerant species, and ii) strategic retention of floodwaters in the backswamp wetlands to reduce the volume and rate during the critical post-flood recession phase. [Copyright &y& Elsevier]

Background and aims: Tecticornia species are stem-succulent, perennial halophytes (sub-family Salicornioideae; Chenopodiaceae) that inhabit saline areas including the margins of ephemeral salt lakes in Australia. Based on zonation observed at salt lakes, species were hypothesised to differ in tolerances to salinity and/or waterlogging. Methods: Three Tecticornia species were grown in sub-irrigated or waterlogged sand culture with treatments from 10 to 800 m M NaCl, for 60 d in a glasshouse. Growth, tissue solutes, root porosity, root radial O loss, and ethanol production, were assessed. Results: The three species were salt tolerant; at 800 m M NaCl shoot RGR (ash-free) was reduced by 9% in T. indica, 22% in T. pergranulata and 39% in T. mellaria. Na and Cl were the predominant osmotica in succulent stem tissues. Glycinebetaine was a major organic solute. T. pergranulata and T. indica were waterlogging tolerant; shoot RGR was reduced by at most 29% irrespective of salinity. Waterlogging tolerance in T. mellaria was variable (shoot RGR 8%-56% of controls) and some individuals died. T. pergranulata formed adventitious roots with aerenchyma, but the two other species did not. Anoxic tips of lateral roots produced ethanol. Conclusion: The three Tecticornia species are salt tolerant. T. pergranulata is also waterlogging tolerant and formed adventitious roots containing aerenchyma, traits consistent with growth on mud flats of salt lakes. T. indica was unexpectedly tolerant of waterlogging, whereas T. mellaria was less tolerant. Future work is needed to evaluate tolerances of inundation (i.e. submergence) and to higher salinity treatments. [ABSTRACT FROM AUTHOR]

Abstract: The biogeochemistry of a tropical shoal bay (Melville Bay, Australia) impacted by the effluent release, precipitation, and deposition of hydrotalcite from an alumina refinery was studied in both wet and dry seasons. Within the deposition zone, sulfate reduction dominated benthic carbon cycling accounting for ≈100% of total microbial activity, with rates greater than those measured in most other marine sediments. These rapid rates of anoxic metabolism resulted in high rates of sulfide and ammonium production and low C:S ratios, implying significant preservation of S in stable sulfide minerals. Rates of total microbial activity were significantly less in control sediments of equivalent grain size, where sulfate reduction accounted for ≈50% of total benthic metabolism. Rates of planktonic carbon cycling overlying the deposition zone were also greater than those measured in the control areas of southern Melville Bay. At the sediment surface, productive algal and cyanobacterial mats helped stabilize the sediment surface and oxidize sulfide to sulfate to maintain a fully oxygenated water-column overlying the impacted zone. The mats utilized a significant fraction of dissolved inorganic N and P released from the seabed; some nutrients escaped to the water-column such that benthic regeneration of NH4 + and PO4 3− accounted for 100% and 42% of phytoplankton requirements for N and P, respectively. These percentages are high compared to other tropical coastal environments and indicate that benthic nutrient recycling may be a significant factor driving water-column production overlying the deposition zone. With regard to remediation, it is recommended that the seabed not be disturbed as attempts at removal may result in further environmental problems and would require specific assessment of the proposed removal process. [Copyright &y& Elsevier]

Coastal environments are threatened by the increasing frequency, extent and severity of hypoxic events. Hypoxia affects vast areas around the world and often causes fish kills, reduced abundance, altered distribution, low benthic biomass and declines in fisheries. In Australia, many fisheries are based on sparid fishes and in the southern states black bream (Acanthopagrus butcheri) is important to both the recreational and commercial sectors. This species completes its entire life cycle in estuaries and annual recruitment is highly variable and very likely influenced by environmental conditions during the spawning season. In a laboratory-based experiment, fertilised black bream eggs (embryos) were exposed to five different levels of dissolved oxygen (DO). The DO levels were maintained in small test wells using nitrogen gas in a novel chamber design. Embryo development was assessed over a 2-day period and hatched larvae were observed until Day 2 post-hatch. Significant differences (p <0.05) were observed in embryonic development and survival as a function of DO level. In severely hypoxic conditions (30% saturation) survival to 1 day was reduced and no hatching occurred. In moderately hypoxic conditions (45–55%S), both precocious and delayed hatching was observed and hatch rates were reduced, whilst the number of hatched larvae with deformities increased, resulting in reduced larval lengths. No larvae survived to Day 2 post-hatch when held in hypoxic conditions (<55%S). This study demonstrates the detrimental effect that severe hypoxia can have on the early development of black bream which could result in reduced recruitment and lowered abundance. Other species that share similar early life histories may also be at risk. [Copyright &y& Elsevier]

In infants most previous studies of the hypoxic ventilatory response (HVR) have been conducted only during quiet sleep (QS) and arousal responses have not been considered. Our aim was to quantify the maturation of the HVR in term infants during both active sleep (AS) and QS over the first 6 months of life. Daytime polysomnography was performed on 15 healthy term infants at 2–5 weeks, 2–3 and 5–6 months after birth and infants were challenged with hypoxia (15% O2, balance N2). Tests in AS always resulted in arousal; in QS tests infants either aroused or did not arouse. A biphasic HVR was observed in non arousing tests at all three ages studied. The fall in SpO2 was more rapid in arousal tests at all three ages. At 2–5 weeks, in non-arousing QS tests, there was a greater fall in respiratory frequency ( f) despite a smaller fall in SpO2 compared with 2–3 and 5–6 months. When infants aroused there was no difference in the HVR between sleep states or with postnatal age. However, when infants failed to arouse from QS, arterial desaturation was less in the younger infants despite a poorer HVR. We suggest that arousal in response to hypoxia, particularly in AS, is a vital survival mechanism throughout the first 6 months of life. [ABSTRACT FROM AUTHOR]

1. Hypoxic conditions occur frequently during hot, dry summers in the small lentic waterbodies (billabongs) that occur on the floodplains of the Murray-Darling River system of Australia. Behavioural responses to progressive hypoxia were examined for the native and introduced floodplain fish of the Ovens River, an unregulated tributary of the Murray River in south-east Australia. 2. Given the high frequency of hypoxic episodes in billabongs on the Ovens River floodplain, it was hypothesised that all species would exhibit behaviours that would confer a degree of hypoxia-tolerance. Specifically, it was hypothesised that as hypoxia progressed, gill ventilation rates (GVRs) would increase and aquatic surface respiration (ASR) would become increasingly frequent. Fish were subjected to rapid, progressive hypoxia from normoxia to anoxia in open tanks. 3. All tested species exhibited behaviours consistent with their use of potentially hypoxic habitats. As hypoxia progressed, GVRs increased and all species, with the exception of oriental weatherloach, began to switch increasingly to ASR with 90% of individuals using ASR at various oxygen concentrations below 1.0 mg O2 L−1. Australian smelt, redfin perch and flat-headed galaxias were the first three species to rise to ASR, with 10% of individuals using ASR by 2.55, 2.29 and 2.21 mg O2 L−1 respectively. Goldfish and common carp were the last two species to rise to ASR, with 10% of individuals using ASR by 0.84 and 0.75 mg O2 L−1 respectively. In contrast to other species, oriental weatherloach largely ceased gill ventilation and used air-gulping as their primary means of respiration during severe hypoxia and anoxia. 4. Australian smelt, redfin perch and flat-headed galaxias were unable to maintain ASR under severe hypoxia, and began exhibiting erratic movements, termed terminal avoidance behaviour, and loss of equilibrium. All other species continued to use ASR through severe hypoxia and into anoxia. Following a rise to ASR, GVRs either remained steady or decreased slightly indicating partial or significant relief from hypoxic stress for these hypoxia-tolerant species. 5. Behavioural responses to progressive hypoxia amongst the fish species of the Ovens River floodplain indicate a generally high level of tolerance to periodic hypoxia. However, species-specific variation in hypoxia-tolerance may have implications for community structure of billabong fish communities following hypoxic events. [ABSTRACT FROM AUTHOR]

Abstract: The Swan-Canning estuary, in southwestern Australia, is subject to frequent algal blooms and associated periods of hypoxia due to high levels of nutrients in stormwater runoff and sewage spills. Fish in which cellular respiration is impaired due to chronic exposure to non-nutrient pollutants in the water will have a reduced ability to survive these periods of high stress. In order to investigate if metabolic respiration in black bream (Acanthopagrus butcheri) was altered, fish were collected from five sites in the Swan-Canning estuary in summer 2001, summer 2002 and winter 2002. Aerobic and anaerobic capacities were estimated by measuring the enzymes cytochrome C oxidase (CCO) and lactate dehydrogenase (LDH). Neither seasonal or annual trends, nor upstream or downstream gradients were observed in either biomarker. The fish collected from the Barrack Street site, which is close to the Perth Central Business District, were heavily challenged in their aerobic capacity in the summer months compared to the other sites. In addition, the fish at Barrack Street displayed an altered anaerobic capacity. It is likely that the impaired metabolic capacity of the fish at Barrack Street reduces the fishes'' ability to survive the frequent algal blooms within the estuary. [Copyright &y& Elsevier]

Functional foods with antioxidant and anti-inflammatory properties are regarded as a complementary therapy to improve chronic diseases such as obesity and inflammatory bowel disease (IBD). Obesity is a chronic low-grade inflammatory state leading to organ damage with increased risk of common diseases including cardiovascular and metabolic disease, non-alcoholic fatty liver disease, osteoarthritis and some cancers. IBD is a chronic intestinal inflammation categorised as Crohn's disease and ulcerative colitis depending on the location of inflammation. These inflammatory states are characterised by normobaric hypoxia in adipose and intestinal tissues, respectively. Tropical foods especially from Australia and South America are discussed in this review to show their potential in attenuation of these chronic diseases. The phytochemicals from these foods have antioxidant and anti-inflammatory activities to reduce chronic normobaric hypoxia in the tissues. These health benefits of the tropical foods are relevant not only for health economy but also in providing a global solution by improving the sustainability of their cultivation and assisting the local economies. [ABSTRACT FROM AUTHOR]

Background: Hypoxemia is a cardinal feature of fibrotic interstitial lung disease (ILD). The incidence, progression, and prognostic significance of hypoxemia in patients with fibrotic ILD currently is unknown., Research Question: What are the epidemiologic features of hypoxemia and its additive prognostic value in a current risk prediction model of fibrotic ILD?, Methods: We identified 848 patients with fibrotic ILD (258 with idiopathic pulmonary fibrosis [IPF]) in five prospective ILD registries from Australia, Canada, and Switzerland. Cumulative incidence of exertional and resting hypoxemia from the time of diagnosis was estimated at 1-year intervals in patients with baseline 6-min walk tests, adjusted for competing risks of death and lung transplantation. Likelihood ratio tests were used to determine the prognostic significance of exertional and resting hypoxemia for 1-year mortality or transplantation when added to the ILD-GAP model. The cohort was divided into derivation and validation subsets to evaluate performance characteristics of the extended model (the ILD-GAP-O 2 model), which included oxygenation status as a predictor., Results: The 1-, 2-, and 5-year overall cumulative incidence was 6.1%, 17.3%, and 40.1%, respectively, for exertional hypoxemia and 2.4%, 5.6%, and 16.5%, respectively, for resting hypoxemia, which were significantly higher in patients with IPF compared with patients without IPF (P < .001 for both). Addition of exertional or resting hypoxemia to the ILD-GAP model improved 1-year mortality and transplantation prediction (P < .001 for both). The ILD-GAP-O 2 model showed improved discrimination (C-index, 0.80 vs 0.75) and model fit (Akaike information criteria, 400 vs 422) in the validation cohort, with comparable calibration., Interpretation: Patients with IPF have higher cumulative incidence of exertional and resting hypoxemia than patients without IPF. The extended ILD-GAP-O 2 model provides additional risk stratification for 1-year prognosis in fibrotic ILD., (Copyright © 2021 American College of Chest Physicians. All rights reserved.)

The article presents several medicine-related articles published in various periodicals. They include one by A. Appelboam and colleagues in the "Lancet" on the use of modified Valsalva in reverting supraventricular tachycardia, another by J. P. Frat and colleagues in the "New England Journal of Medicine" on the use of high-flow nasal oxygen for acute hypoxaemic respiratory failure and one by O. G. Doluoglu and colleagues in "Urology" on the role of sexual intercourse in ureteric stone passage.

In this article the authors comment on an Australian study which looks into the high-concentration oxygen therapy in chronic obstructive pulmonary disease (COPD). The authors assert that the study discovers that titrated oxygen treatment lessens the risk of death in patients with acute exacerbations (AE) of COPD. They suggest that risks of both hypoxaemia and hyperoxaemia can be can avoided through titrate oxygen treatment.

The article presents developments in the Australian and New Zealand Hyperbaric Medicine Group (ANZHMG). The author announces the submission of reports to the Australian Federal Government Medical Services Authority Committee (MSAC) which seeks subsidy from Medicare for hyperbaric oxygen treatment of soft-tissue radiation injury and necrosis and non-diabetic problem wounds caused by hypoxia. He stresses that the reports are supported by the Australian Society of Anaesthetists and Australian Medical Association. A brief outline of the reports is provided.