A multicentre prospective observational study comparing arterial blood gas values to those obtained by pulse oximeters used in adult patients attending Australian and New Zealand hospitals.

BACKGROUND: Pulse oximetry is widely used in the clinical setting. The purpose of this validation study was to investigate the level of agreement between oxygen saturations measured by pulse oximeter (SpO2) and arterial blood gas (SaO2) in a range of oximeters in clinical use in Australia and New Zealand. METHODS: Paired SpO2 and SaO2 measurements were collected from 400 patients in one Australian and two New Zealand hospitals. The ages of the patients ranged from 18 to 95 years. Bias and limits of agreement were estimated. Sensitivity and specificity for detecting hypoxaemia, defined as SaO2 < 90%, were also estimated. RESULTS: The majority of participants were recruited from the Outpatient, Ward or High Dependency Unit setting. Bias, oximeter-measured minus arterial blood gas-measured oxygen saturation, was - 1.2%, with limits of agreement - 4.4 to 2.0%. SpO2 was at least 4% lower than SaO2 for 10 (2.5%) of the participants and SpO2 was at least 4% higher than the SaO2 in 3 (0.8%) of the participants. None of the participants with a SpO2 ≥ 92% were hypoxaemic, defined as SaO2 < 90%. There were no clinically significant differences in oximetry accuracy in relation to clinical characteristics or oximeter brand. CONCLUSIONS: In the majority of the participants, pulse oximetry was an accurate method to assess SaO2 and had good performance in detecting hypoxaemia. However, in a small proportion of participants, differences between SaO2 and SpO2 could have clinical relevance in terms of patient monitoring and management. A SpO2 ≥ 92% indicates that hypoxaemia, defined as a SaO2 < 90%, is not present. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry (ACTRN12614001257651). Date of registration: 2/12/2014.

The effect of 50% oxygen on PtCO2 in patients with stable COPD, bronchiectasis, and neuromuscular disease or kyphoscoliosis: randomised cross-over trials.

BACKGROUND: High-concentration oxygen therapy causes increased arterial partial pressure of carbon dioxide (PaCO2) in patients with COPD, asthma, pneumonia, obesity and acute lung injury. The objective of these studies was to investigate whether this physiological response to oxygen therapy occurs in stable patients with neuromuscular disease or kyphoscoliosis, and bronchiectasis. METHODS: Three randomised cross-over trials recruited stable patients with neuromuscular disease or kyphoscoliosis (n = 20), bronchiectasis (n = 24), and COPD (n = 24). Participants were randomised to receive 50% oxygen and 21% oxygen (air), each for 30 min, in randomly assigned order. The primary outcome was transcutaneous partial pressure of carbon dioxide (PtCO2) at 30 min. The primary analysis was a mixed linear model. RESULTS: Sixty six of the 68 participants had baseline PtCO2 values < 45 mmHg. The intervention baseline adjusted PtCO2 difference (95% CI) between oxygen and room air after 30 min was 0.2 mmHg (- 0.4 to 0.9), P = 0.40; 0.5 mmHg (- 0.2 to 1.2), P = 0.18; and 1.3 mmHg (0.7 to 1.8), P < 0.001, in the neuromuscular/kyphoscoliosis, bronchiectasis and COPD participants respectively. CONCLUSIONS: The small increase in PtCO2 in the stable COPD patients with high-concentration oxygen therapy contrasts with the marked increases in PaCO2 seen in the setting of acute exacerbations of COPD. This suggests that the model of studying the effects of high-concentration oxygen therapy in patients with stable respiratory disease is not generalisable to the use of oxygen therapy in the acute clinical setting. Appropriate studies of high-concentration compared to titrated oxygen in acute clinical settings are needed to determine if there is a risk of oxygen-induced hypercapnia in patients with neuromuscular disease, kyphoscoliosis or bronchiectasis. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12615000970549 Registered 16/9/15, ACTRN12615000971538 Registered 16/9/15 and ACTRN12615001056583 Registered 7/10/15.

Nasal high flow therapy and PtCO2 in stable COPD: A randomized controlled cross-over trial.

BACKGROUND AND OBJECTIVE: Hypercapnia is associated with worse clinical outcomes in exacerbations of COPD. The present study aimed to determine the effects of nasal high flow (NHF) therapy on transcutaneous partial pressure of carbon dioxide (PtCO2 ) in stable COPD patients. METHODS: In a single-blind randomized controlled cross-over trial, 48 participants with COPD were allocated in random order to all of four 20 min interventions: NHF at 15 L/min, 30 L/min and 45 L/min or breathing room air with each intervention followed by a washout period of 15 min. The primary outcome measure was PtCO2 at 20 min, adjusted for baseline PtCO2 . Secondary outcomes included respiratory rate at 20 min, adjusted for baseline. RESULTS: The mean (95% CI) change in PtCO2 at 20 min was -0.6 mm Hg (-1.1 to 0.0), P = 0.06; -1.3 mm Hg (-1.9 to 0.8), P < 0.001; and -2.4 mm Hg (-2.9 to -1.8), P < 0.001; for NHF at 15 L/min, 30 L/min and 45 L/min compared with room air, respectively. The mean (95% CI) change in respiratory rate at 20 min was -1.5 (-2.7 to -0.3), P = 0.02; -4.1 (-5.3 to -2.9), P < 0.001; and -4.3 (-5.5 to -3.1), P < 0.001; breaths per minute compared with room air, respectively. CONCLUSION: NHF results in a small flow-dependent reduction in PtCO2 and respiratory rate in patients with stable COPD.

Oxygen versus air-driven nebulisers for exacerbations of chronic obstructive pulmonary disease: a randomised controlled trial.

BACKGROUND: In exacerbations of chronic obstructive pulmonary disease, administration of high concentrations of oxygen may cause hypercapnia and increase mortality compared with oxygen titrated, if required, to achieve an oxygen saturation of 88-92%. Optimally titrated oxygen regimens require two components: titrated supplemental oxygen to achieve the target oxygen saturation and, if required, bronchodilators delivered by air-driven nebulisation. The effect of repeated air vs oxygen-driven bronchodilator nebulisation in acute exacerbations of chronic obstructive pulmonary disease is unknown. We aimed to compare the effects of air versus oxygen-driven bronchodilator nebulisation on arterial carbon dioxide tension in exacerbations of chronic obstructive pulmonary disease. METHODS: A parallel group double-blind randomised controlled trial in 90 hospital in-patients with an acute exacerbation of COPD. Participants were randomised to receive two 2.5 mg salbutamol nebulisers, both driven by air or oxygen at 8 L/min, each delivered over 15 min with a 5 min interval in-between. The primary outcome measure was the transcutaneous partial pressure of carbon dioxide at the end of the second nebulisation (35 min). The primary analysis used a mixed linear model with fixed effects of the baseline PtCO2, time, the randomised intervention, and a time by intervention interaction term; to estimate the difference between randomised treatments at 35 min. Analysis was by intention-to-treat. RESULTS: Oxygen-driven nebulisation was terminated in one participant after 27 min when the PtCO2 rose by > 10 mmHg, a predefined safety criterion. The mean (standard deviation) change in PtCO2 at 35 min was 3.4 (1.9) mmHg and 0.1 (1.4) mmHg in the oxygen and air groups respectively, difference (95% confidence interval) 3.3 mmHg (2.7 to 3.9), p < 0.001. The proportion of patients with a PtCO2 change ≥4 mmHg during the intervention was 18/45 (40%) and 0/44 (0%) for oxygen and air groups respectively. CONCLUSIONS: Oxygen-driven nebulisation leads to an increase in PtCO2 in exacerbations of COPD. We propose that air-driven bronchodilator nebulisation is preferable to oxygen-driven nebulisation in exacerbations of COPD. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry number ACTRN12615000389505 . Registration confirmed on 28/4/15.

High flow or titrated oxygen for obese medical inpatients: a randomised crossover trial.

OBJECTIVE: To compare the effects on transcutaneous carbon dioxide tension (Ptco2) of high concentration and titrated oxygen therapy in medical inpatients with morbid obesity who were not selected for a pre-existing diagnosis of obesity hypoventilation syndrome. DESIGN: A randomised, crossover trial undertaken between February and September 2015. SETTING: Internal medicine service, Wellington Regional Hospital, New Zealand. PARTICIPANTS: 22 adult inpatients, aged 16 years or more, with a body mass index exceeding 40 kg/m2. INTERVENTIONS: Participants received in random order two 60-minute interventions, with a minimum 30-minute washout period between treatments: titrated oxygen therapy (oxygen delivered, if required, via nasal prongs to achieve peripheral oxygen saturation [Spo2] of 88-92%), and high concentration oxygen therapy (delivered via Hudson mask at 8 L/min, without regard to Spo2). Ptco2 and Spo2 were recorded at 10-minute intervals. MAIN OUTCOME MEASURE: Ptco2 at 60 minutes, adjusted for baseline. RESULTS: Baseline Ptco2 was 45 mmHg or lower for 16 participants with full data (73%). The mean difference in Ptco2 between high concentration and titrated oxygen therapy at 60 minutes was 3.2 mmHg (95% CI, 1.3-5.2 mmHg; P = 0.002). CONCLUSION: High concentration oxygen therapy increases Ptco2 in morbidly obese patients. Our findings support guidelines that advocate oxygen therapy, if required in patients with morbid obesity, be titrated to achieve a target Spo2 of 88-92%. CLINICAL TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, ACTRN12610000522011.

Physiological effects of titrated oxygen via nasal high-flow cannulae in COPD exacerbations: A randomized controlled cross-over trial.

BACKGROUND AND OBJECTIVE: Increased arterial carbon dioxide tension (PaCO2 ) is an important complication of acute exacerbations of COPD. The effects of nasal high-flow cannulae (NHF) on PaCO2 in patients with COPD exacerbations, and whether this therapy should be used in this clinical situation, are less certain. We aimed to investigate the effect of NHF on PaCO2 in patients admitted to hospital with a COPD exacerbation. METHODS: We performed a single-centre randomized controlled cross-over trial in 24 hospital inpatients with acute exacerbations of COPD receiving oxygen via standard nasal prongs (SNPs). Patients received both supplemental oxygen via NHF (35 L/min) and SNP for 30 min each, with oxygen titrated to maintain the patient's baseline oxygen saturation, measured by pulse oximetry (SpO2 ). Interventions were administered in random order with a minimum 15-min washout between interventions. The primary outcome was difference in transcutaneous carbon dioxide tension (PtCO2 ) at 30 min adjusted for time zero. RESULTS: The difference in PtCO2 adjusted for time zero was lower after 30 min for NHF compared with SNP (-1.4 mm Hg (95% CI: -2.2 to -0.6), P = 0.001). There was no difference in SpO2 at 30 min (-0.02% (95% CI: -0.8 to 0.7), P = 0.96). The reduction in respiratory rate for NHF at 30 min was not statistically significant (-2.0 breaths/min (95% CI: -4.5 to 0.4), P = 0.099). CONCLUSION: Short-term use of NHF results in a small reduction in PtCO2 compared with SNP in patients with acute exacerbations of COPD, but whether this is clinically significant is uncertain.

Target oxygen saturation range: 92-96% Versus 94-98.

This scientific letter considers the rationale for the target oxygen saturation measured by pulse oximetry (SpO2 ) range of 92-96% for oxygen therapy in adult patients without COPD or other conditions associated with chronic respiratory failure, recommended by the Thoracic Society of Australia and New Zealand, in contrast to the 94-98% target range recommended by the British Thoracic Society. We conclude from the available evidence that the SpO2 target of 92-96% may be preferable to 94-98%.

Effect of smoking status on the efficacy of the SMART regimen in high risk asthma.

BACKGROUND AND OBJECTIVE: The optimal management of people with asthma with a significant smoking history is uncertain. The aim of this study was to determine whether the efficacy/safety profile of single combination inhaled corticosteroid (ICS)/long acting beta-agonist (LABA) inhaler maintenance and reliever therapy is influenced by smoking status. METHODS: We undertook secondary analyses from an open-label 24-week randomized study of 303 high risk adult asthma patients randomized to budesonide/formoterol 200/6-µg-metred dose inhaler for maintenance (two actuations twice daily) and either budesonide/formoterol 200/6-µg-metred dose inhaler one actuation ('single ICS/LABA maintenance and reliever therapy (SMART)' regimen) or salbutamol 100 µg 1-2 actuations for symptom relief ('Standard' regimen). Smoking status was classified in to three groups, as 'current', 'ex' or 'never', and a smoking/treatment interaction term tested for each outcome variable. The primary outcome variable was number of participants with at least one severe exacerbation. RESULTS: There were 59 current, 97 ex and 147 never smokers included in the analyses. The smoking status/treatment interaction term was not statistically significant for any of the outcome measures. With adjustment for smoking status, the number of participants with severe exacerbations was lower with the SMART regimen (OR 0.45, 95% CI: 0.26-0.77, P = 0.004; P value for interaction between smoking status and treatment 0.29). CONCLUSION: We conclude that the favourable safety/efficacy profile of the SMART regimen applies to patients with high risk asthma, irrespective of smoking status.

Thoracic Society of Australia and New Zealand oxygen guidelines for acute oxygen use in adults: 'Swimming between the flags'.

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.

Comparative audit of oxygen use in the prehospital setting in acute COPD exacerbation over 5†years.

BACKGROUND: In 2009 the Wellington Free Ambulance implemented an education programme to reduce high concentration oxygen delivery to patients with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD). The aim of this audit was to compare pre-hospital oxygen delivery to patients with AECOPD before and after the programme. METHODS: An audit of patients who presented to Wellington Regional Hospital by ambulance with an AECOPD in 2005 and then in 2010, after implementation of the education programme. Oxygen therapy was categorised as: HIGH, supplemental high concentration oxygen therapy ≥3 L/min and/or delivery via high concentration mask; NEB, high concentration oxygen only during nebuliser use; or LOW, neither of these. RESULTS: In 2005 those in the HIGH, NEB and LOW categories were 81 (75.0%), 18 (16.7%) and 9 (8.3%) of 108 identified patients. In 2010 those in the HIGH, NEB and LOW categories were 80 (44.0%), 61 (33.5%) and 41 (22.5%) of 182 identified patients. The proportions of patients in the three oxygen groups were significantly different between 2005 and 2010 (p<0.001). CONCLUSIONS: The proportion of patients administered supplemental high concentration oxygen therapy markedly decreased between 2005 and 2010 following implementation of the education programme. However, in 2010 more than half of the patients not managed with high concentration oxygen therapy were still exposed to high concentration oxygen through the use of oxygen-driven nebulisers. To reduce exposure to high concentration oxygen in AECOPD the use of air-driven nebulisers or metered dose inhalers with spacers is required.

Acute use of oxygen therapy.

A major change is needed in the entrenched culture of routinely administering high-concentration oxygen to acutely ill patients regardless of need. Oxygen is a drug that should be prescribed for specific indications. There should be a documented target range for oxygen saturation, and regular monitoring of the patient's response. There are risks from unrelieved hypoxaemia due to insufficient oxygen therapy, and from provoked hyperoxaemia due to excessive oxygen therapy. Oxygen therapy should therefore be titrated so that the saturation is within a range that avoids these risks. If oxygen requirements are increasing, the clinician should review the patient and consider transfer to a higher level of care. If oxygen requirements are decreasing, consider reducing or discontinuing oxygen therapy.

Combination budesonide/formoterol inhaler as maintenance and reliever therapy in Maori with asthma.

BACKGROUND AND OBJECTIVE: There are significant health disparities between Maori and non-Maori with asthma, a pattern seen between other ethnic populations. This study investigates outcomes for Maori in a randomized controlled trial (RCT) of combination budesonide/formoterol inhaler therapy in asthma. METHODS: This 24-week multicentre RCT recruited 303 adult asthma patients, 44 of whom were Maori. Participants were randomized to the single combination budesonide/formoterol inhaler as maintenance and reliever therapy ('SMART') regimen or 'standard' regimen (combination budesonide/formoterol inhaler for maintenance and salbutamol as reliever). Outcomes included patterns of beta-agonist inhaler use including 'high use' of reliever therapy (>8 actuations of budesonide/formoterol in excess of four maintenance doses per day for SMART and >16 actuations per day of salbutamol for standard). Differences in outcomes for Maori versus non-Maori were assessed using an interaction term between ethnicity and treatment. RESULTS: With adjustment for ethnicity, the SMART group had fewer days of high use (relative rate (RR) 0.57 (95% confidence interval (CI): 0.38-0.85)), days of high use without medical review within 48 h (RR 0.49 (95% CI: 0.32-0.75)) and severe exacerbations (RR 0.54 (95% CI: 0.36-0.81)) compared with standard. The magnitude of the benefit from the SMART regimen was similar in Maori and non-Maori. Regardless of treatment regimen, Maori demonstrated more days of high use, high use without medical review and underuse of maintenance therapy. CONCLUSIONS: The SMART regimen has a favourable risk/benefit profile in Maori. Days of high use, days of high use without medical review and underuse of maintenance treatment were greater in Maori, regardless of treatment regimen.

A pilot study investigating the effects of remote ischemic preconditioning in high-risk cardiac surgery using a randomised controlled double-blind protocol.

The efficacy of remote ischemic preconditioning (RIPC) in high-risk cardiac surgery is uncertain. In this study, 96 adults undergoing high-risk cardiac surgery were randomised to RIPC (3 cycles of 5 min of upper-limb ischemia induced by inflating a blood pressure cuff to 200 mmHg with 5 min of reperfusion) or control. Main endpoints were plasma high-sensitivity troponin T (hsTNT) levels at 6 and 12 h, worst post-operative acute kidney injury (AKI) based on RIFLE criteria, and noradrenaline duration. hsTNT levels were log-normally distributed and higher with RIPC than control at 6-h post cross-clamp removal [810 ng/ml (IQR 527-1,724) vs. 634 ng/ml (429-1,012); ratio of means 1.41 (99.17% CI 0.92-2.17); P=0.04] and 12 h [742 ng/ml (IQR 427-1,700) vs. 514 ng/ml (IQR 356-833); ratio of means 1.56 (99.17% CI 0.97-2.53); P=0.01]. After adjustment for baseline confounders, the ratio of means of hsTNT at 6 h was 1.23 (99.17% CI 0.88-1.72; P=0.10) and at 12 h was 1.30 (99.17% CI 0.92-1.84; P=0.05). In the RIPC group, 35/48 (72.9%) had no AKI, 5/48 (10.4%) had AKI risk, and 8/48 (16.7%) had either renal injury or failure compared to the control group where 34/48 (70.8%) had no AKI, 7/48 (14.6%) had AKI risk, and 7/48 (14.6%) had renal injury or failure (Chi-squared 0.41; two degrees of freedom; P = 0.82). RIPC increased post-operative duration of noradrenaline support [21 h (IQR 7-45) vs. 9 h (IQR 3-19); ratio of means 1.70 (99.17% CI 0.86-3.34); P=0.04]. RIPC does not reduce hsTNT, AKI, or ICU-support requirements in high-risk cardiac surgery.

The risk of serious adverse outcomes associated with hypoxaemia and hyperoxaemia in acute exacerbations of COPD.

BACKGROUND: Prehospital high concentration oxygen therapy leads to worse clinical outcomes in patients presenting with acute exacerbations of chronic obstructive pulmonary disease (AECOPD). Less is known about the risks of hypoxaemia despite oxygen treatment. Current respiratory and ambulance guidelines recommend titration of supplemental oxygen to a target oxygen saturation range of 88%-92%. AIM: To explore the association between PaO(2) and risk of serious adverse clinical outcomes in AECOPD. METHODS: A retrospective review of consecutive patients presenting via ambulance to the Wellington Regional Hospital Emergency Department with AECOPD between June 2005 and January 2008. Patients with an arterial blood gas taken within 4 h of triage were included in the study and were categorised as hypoxaemic (PaO(2)<60 mm Hg), normoxaemic (PaO(2) 60-100 mm Hg) or hyperoxaemic (PaO(2)>100 mm Hg). Serious adverse outcome was defined as a composite of hypercapnic respiratory failure, assisted ventilation or inpatient death. Multivariate logistic regression analysis examined the association between PaO(2) category and the composite outcome. RESULTS: Of the 680 patients presenting with AECOPD in the review period, 254 presentations in 180 patients had data suitable for analysis. Hyperoxaemia occurred in 61/254 (24%) presentations and was strongly associated with serious adverse outcome compared with normoxaemia (OR 9.17, 95% CI 4.08 to 20.6). Hypoxaemia was also associated with an increased risk of serious adverse outcome compared with normoxaemia (OR 2.16, 95% CI 1.11 to 4.20). Compared with the recommended target oxygen saturation range of 88%-92%, the risk of a serious adverse outcome was increased in both the <88% group (OR 2.0, 95% CI 1.03 to 3.80) and the >96% group (OR 2.37, 95% CI 1.34 to 4.20). CONCLUSIONS: In patients presenting via ambulance to the Emergency Department with AECOPD, serious adverse clinical outcomes are associated with both hypoxaemia and hyperoxaemia. These data provide further support for the principle of titrating supplemental oxygen therapy to target oxygen saturations.

Beta-agonist overuse and delay in obtaining medical review in high risk asthma: a secondary analysis of data from a randomised controlled trial.

Asthma mortality surveys report delays in seeking medical review and overuse of beta-agonist therapy as factors contributing to a fatal outcome. However, the strength of these associations is limited because many asthma deaths are unwitnessed. We undertook a secondary analysis of data from a 24-week randomised controlled trial of 303 patients with high-risk asthma, randomised to combination budesonide/formoterol inhaler according to a single maintenance and reliever therapy regimen or fixed dose budesonide/formoterol with salbutamol as reliever (Standard) regimen. Medication use was measured by electronic monitors. The thresholds for high, marked and extreme beta-agonist use days were defined in the single maintenance and reliever therapy arm as: >8, >12 and >16 actuations of budesonide/formoterol in excess of four maintenance doses, respectively; and in the Standard arm as: >16, >24 and >32 actuations of salbutamol, respectively. Whether a medical review was obtained within 48 h of an overuse episode was determined by review of data collected during the study by participant report. The mean (standard deviation) proportion of days in which high, marked and extreme beta-agonist overuse occurred without medical review within 48 h was 0·94(0·20), 0·94(0·15) and 0·94(0·17), and 0·92(0·19), 0·90(0·26) and 0·94(0·15) for single maintenance and reliever therapy and Standard regimens, respectively. In at least 90% of days, in which beta-agonist overuse occurred, patients did not obtain medical review within 48 h of beta-agonist overuse, regardless of the magnitude of overuse or the inhaled corticosteroid/long-acting beta-agonist regimen. RELIEVER INHALER OVERUSE AND DELAY IN MEDICAL REVIEW IN ASTHMA: In asthma, overuse of beta-agonist reliever medication and delay in seeking medical review in an exacerbation are linked to asthma deaths. Janine Pilcher at the Medical Research Institute of New Zealand, and co-workers, conducted a review of data from a study of 303 adult patients with severe asthma, followed over 24 weeks. The patients were allocated to either a budesonide/formoterol, or a salbutamol inhaler to take for symptom relief, in addition to their maintenance treatment. Inhalers were fitted with electronic monitors, to accurately document every use. In both groups, on 90% of days when an exacerbation requiring excess use of an inhaler occurred, patients did not follow-up with medical professionals within 48 h as advised. Further, in both groups, 'extreme' reliever inhaler use was recorded at least once in around one in four patients.

RCT of the effect of berryfruit polyphenolic cultivar extract in mild steroid-naive asthma: a cross-over, placebo-controlled study.

OBJECTIVE: There is preclinical evidence that consumption of berryfruit extract may reduce chronic airways inflammation and modify airway remodelling in allergen-induced models of lung inflammation. We investigated the effect of berryfruit extract on the fractional expired nitric oxide (FeNO), a biomarker of eosinophilic airways inflammation, in adults with steroid-naïve asthma. DESIGN: Randomised placebo-controlled cross-over double-blind trial. SETTING: Single-centre community-based trial. PARTICIPANTS: 28 steroid-naïve mild asthmatics with Feno >40 ppb, of whom 25 completed both study interventions. INTERVENTIONS: Participants were randomised to receive, according to the cross-over design, 100 mg berryfruit polyphenolic extract (BFPE) or placebo for 4 weeks, with a 4-week washout period between the interventions. PRIMARY OUTCOME MEASURE: The primary outcome variable was FeNO at 4 weeks, analysed by a mixed linear model, with a random effect for participant and baseline FeNo as a covariate. RESULTS: The mean (SD) natural logarithm transformed (ln) FeNO after 4 weeks of treatment for the BFPE and placebo groups was 4.28 (0.47) and 4.22 (0.47), respectively. The paired change from baseline mean (SD) BFPE minus placebo ln FeNO was -0.03 (0.39), N=25. The mixed linear model estimate, with baseline covariate adjustment, difference in ln FeNO, was -0.002 (95% CI -0.15 to 0.14), p=0.98. This is equivalent to a ratio of geometric mean FeNO of 1.0 (95% CI 0.86 to 1.15). CONCLUSIONS: In steroid-naïve participants with mild asthma and elevated FeNO, there was no effect of BFPE on FeNO, a biomarker of eosinophilic airways inflammation. Caution is required in the extrapolation of apparent benefit in murine models of lung eosinophilia to clinical efficacy in patients with asthma. TRIAL REGISTRATION NUMBER: ANZCTR: 12613000451707; Results.