Audit of oxygen administration to achieve a target oxygen saturation range in acutely unwell medical patients.

PURPOSE OF THE STUDY: To evaluate documentation of a target oxygen saturation (SpO2) range and ability to achieve this range in acutely unwell inpatients. STUDY DESIGN: In this single-centre audit, patients with discharge diagnoses of pneumonia, heart failure and exacerbation of asthma or COPD admitted to Wellington Regional Hospital, New Zealand between 1 June 2019 and 31 August 2019 who received oxygen were identified. In those with a documented target SpO2 range, the proportion of SpO2 measurements in the observation chart which were within, above and below range were determined as well as the maximum and minimum SpO2. Regression analysis was performed to determine whether these outcomes were influenced by the prescribed range, high-dependency care or the number of adjustments to oxygen administration. RESULTS: 268 admissions were screened. Of the 100 eligible admissions who received oxygen, a target SpO2 range was documented in 62. The mean (SD) proportion of SpO2 measurements within range was 56.2 (30.6)%. A hypercapnic target SpO2 range was associated with a higher probability of an SpO2 above range; multivariate OR 5.34 (95% CI 1.65 to 17.3, p=0.006) and a lower probability of an SpO2 below range; multivariate OR 0.25 (95% CI 0.08 to 0.80) p=0.02. The mean (SD) maximum SpO2 was similar in those with a target range of 92%-96% versus a hypercapnic range; 96.2 (3.0)% and 95.2 (3.4)%, respectively. CONCLUSIONS: Oxygen prescription and delivery in this clinical setting was suboptimal. SpO2 values above the designated range are common, particularly in patients with a hypercapnic target range.

Determination of oxygen saturation compared to a prescribed target range using continuous pulse oximetry in acutely unwell medical patients.

BACKGROUND: Both inadequate and excessive administration of oxygen to acutely unwell patients results in risk of harm. Guidelines recommend titration of oxygen to achieve a target oxygen saturation (SpO2) range. Information regarding whether this is being achieved is limited. METHODS: In this two-centre non-interventional study we used continuous pulse oximetry in acutely unwell medical patients over a 24-h period to determine the proportion of time spent with SpO2 within the prescribed target range and whether this is influenced by the target range, age, care in a high-dependency area and the number of oxygen adjustments. RESULTS: Eighty participants were included in the analysis. The mean (SD) proportion of time spent in target range was 55.6% (23.6), this was lower in those with a reduced hypercapnic target range (88-92% or below) compared to those with a range of 92-96%; difference - 13.1% (95% CI - 3.0 to - 23.2), P = 0.012. The proportion of time spent above range was 16.2% (22.9); this was higher in those with a reduced hypercapnic range; difference 21.6% (31.4 to 12), P < 0.001. The proportion of time below range was 28.4% (25.2); there was no difference between target ranges. The proportion of time spent in range was higher for those in a high dependency area in the multivariate model; difference 15.5% (95% CI 2.3 to 28.7), P = 0.02. CONCLUSIONS: Medical patients receiving oxygen in a ward setting spend significant periods of time with SpO2 both above and below the prescribed target range while receiving oxygen therapy.

Inhaled Corticosteroid Therapy in Adult Asthma. Time for a New Therapeutic Dose Terminology.

The Global Initiative for Asthma guidelines use the traditional terminology of "low," "medium," and "high" doses of inhaled corticosteroids (ICS) to define daily maintenance doses of 100 to 250 µg, >250 to 500 µg, and >500 µg, respectively, of fluticasone propionate or equivalent for adults with asthma. This concise clinical review proposes that this terminology is not evidence based and that prescribing practice based on this terminology may lead to the use of inappropriately excessive doses of ICS. Specifically, the ICS dose that achieves 80-90% of the maximum obtainable benefit is currently classified as a low dose, with the description of two higher dose levels of medium and high, which are associated with significant risk of systemic adverse effects. Asthma guidelines and clinician prescribing practice need to be modified in accordance with the currently available evidence of the dose-response relationship of ICS in adult asthma. We propose a reclassification of ICS doses based on a "standard daily dose," which is defined as 200-250 µg of fluticasone propionate or equivalent, representing the dose at which approximately 80-90% of the maximum achievable therapeutic benefit of ICS is obtained in adult asthma across the spectrum of severity. It is recommended that ICS treatment be started at these standard doses, which then represent the doses at which maintenance ICS are prescribed at step 2 and within ICS/long-acting ß-agonist combination therapy at step 3. The opportunity is available to prescribe higher doses within ICS/long-acting ß-agonist maintenance therapy in accordance with the stepwise approach to asthma treatment at step 4.

Dose-response relationship of ICS/fast-onset LABA as reliever therapy in asthma.

BACKGROUND AND OBJECTIVE: The dose-response relationship of inhaled corticosteroid (ICS)/fast-onset long acting beta agonist (LABA) reliever therapy has not been formally addressed. The objective of this retrospective analysis is to ascertain from the available evidence whether ICS/fast-onset LABA administered as reliever therapy has a different dose-response relationship than maintenance fixed dose ICS/fast-onset LABA therapy in reducing risk of severe exacerbations. METHODS: A systematic literature review was undertaken to identify randomised controlled trials (RCTs) in which randomised treatments included either i) budesonide/formoterol reliever monotherapy versus budesonide/formoterol fixed dose maintenance with short acting beta agonist (SABA) reliever therapy, or ii) budesonide/formoterol reliever therapy in addition to budesonide/formoterol maintenance versus higher fixed dose maintenance budesonide/formoterol with SABA as reliever therapy. Eligible studies were reviewed to allow determination of the relative potency and efficacy of the comparator regimens to reduce the risk of a severe exacerbation. RESULTS: The one RCT of budesonide/formoterol reliever monotherapy showed a 4.6-fold (95% CI 2.9 to 7.3) greater potency than budesonide/formoterol fixed dose maintenance plus SABA reliever therapy in reducing the risk of severe exacerbations. In the one RCT that compared budesonide/formoterol maintenance and reliever therapy with higher fixed dose maintenance budesonide/formoterol plus SABA reliever therapy, there was an additional 26% (95% CI 4 to 42%) reduction in severe exacerbation risk with the addition of budesonide/formoterol reliever therapy to maintenance budesonide/formoterol, despite a 25% lower total budesonide/formoterol dose. CONCLUSION: The limited available evidence suggests that budesonide/formoterol reliever therapy has greater potency and efficacy than budesonide/formoterol fixed dose maintenance plus SABA reliever therapy in reducing the risk of a severe exacerbation. This is an important concept which has the potential to guide clinical practice in asthma, although the small number of studies available highlights the need for further research to better define these pharmacological properties.

Automatic versus manual oxygen titration using a novel nasal high-flow device in medical inpatients with an acute illness: a randomised controlled trial.

BACKGROUND: Guideline recommendations state oxygen should be administered to acutely unwell patients to achieve a target oxygen saturation (SpO2) range. The current practice of manual oxygen titration frequently results in SpO2 outside of a prescribed range. The aim of this study was to assess the efficacy of automatic oxygen titration using a closed-loop feedback system to achieve SpO2 within a prescribed target range METHODS: An open-label randomised parallel group trial was undertaken comparing automatic oxygen titration using a novel nasal high-flow device to manual oxygen titration using nasal high flow. Medical inpatients requiring oxygen therapy in Wellington Regional Hospital, New Zealand with a prescribed target SpO2 range of 88%-92% or 92%-96% were recruited and randomised equally between the interventions for a period of 24 hours. The primary outcome was the proportion of time spent with SpO2 within the prescribed range. RESULTS: 20 patients were included in the analysis. Automatic oxygen titration resulted in a median (IQR) 96.2% (95.2-97.8) of time within the target range compared with 71% (59.4-88.3) with manual titration; difference (95% CI) 24.2% (7.9% to 35%), p<0.001. There was a reduction in the time spent with SpO2 ≥2% above and ≥2% below range in the automatic titration group, although the point estimate for the differences were small; -1% (-8.2% to -0.04%), p=0.017 and -2.4% (-11.5% to 0.3%), p=0.05 respectively. CONCLUSIONS: Nasal high-flow with automatic oxygen titration resulted in a greater proportion of time spent with SpO2 in target range compared with manual titration. TRIAL REGISTRATION: The trial was registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12619000901101).

Closed-Loop Oxygen Control Using a Novel Nasal High-Flow Device: A Randomized Crossover Trial.

BACKGROUND: Oxygen administration is recommended for patients with hypoxemia to achieve a target [Formula: see text] range. Strategies to achieve this in clinical practice are suboptimal. We investigated automatic oxygen titration using a novel nasal high-flow device with closed-loop oxygen control. The objective of this proof-of-concept study was to determine whether closed-loop control was able to respond to desaturation and subsequent recovery in a controlled laboratory-based environment. METHODS: We conducted a single-blind randomized crossover trial in adults with chronic respiratory disease who had a resting [Formula: see text] ≥ 92% and desaturated to < 90% during a 6-min walk test (6MWT). Nasal high-flow was administered during a 6MWT and a subsequent 10-min rest period with either room air, a fixed concentration of 28% oxygen, or oxygen titrated automatically using closed-loop control. RESULTS: The study involved 42 subjects. Closed-loop control maintained [Formula: see text] within the target range of 92-96% for a mean (SD) duration of 54.4 ± 30.1% of the 6MWT and 67.3 ± 26.8% of the recovery period. The proportion of time spent with an [Formula: see text] in the target range during the 6MWT was significantly greater for closed-loop control compared to room air, with a difference of 26.0% (95% CI 17.7-34.2, P < .001); this proportion of time was not significantly different compared to the fixed concentration of 28% oxygen, with a difference of -8.2% (95% CI -16.5 to 0.1, P = .052). The proportion of time spent in the target range during the rest period was significantly greater compared to 28% oxygen, with a difference of 19.3% (95% CI 8.9-29.7, P < .001); this proportion of time was not significantly different compared to room air, with a difference of -9.3% (95% CI -19.7 to 1.0, P = .08). CONCLUSIONS: This study provides proof-of-concept evidence that the novel nasal high-flow device with closed-loop control can respond to changes in [Formula: see text] outside a target saturation range using a model of exercise-induced desaturation and subsequent recovery.

Rhinothermy delivered by nasal high flow therapy in the treatment of the common cold: a randomised controlled trial.

BACKGROUND: The common cold is the most common infectious disease affecting humans and has a substantial economic impact on society. Human rhinoviruses, which cause almost two-thirds of colds, have demonstrated temperature-dependent replication which is optimal between 33°C and 35°C. METHODS: This randomised, single-blind, parallel-group trial completed at a single-centre in New Zealand, recruited 170 participants aged 18-75 years (mean age 27.5 years) who were within 48 hours of common cold symptom onset and had a symptom score (the Modified Jackson Score (MJS)) ≥7 and a negative point-of-care test for influenza. Participants were blinded to the intervention and randomised (1:1) to 5 days of either nasal high flow rhinothermy (rNHF) (100% humidified air delivered at 35 L/min and 41°C for 2 hours daily) (n=85) or 'sham' rhinothermy (100% humidified air delivered at 10 L/min and 31°C for 10 min daily) (n=85) and completed daily symptom diaries, which included the MJS, for 14 days, to investigate whether rNHF reduced common cold symptom severity and duration compared with 'sham' rhinothermy. RESULTS: An intention-to-treat superiority analysis included all randomised participants and showed no difference between treatment groups for the primary outcome, the day 4 MJS analysed by analysis of covariance: mean (SD) 6.33 (3.97) for rNHF vs 5.8 (3.15) for 'sham'; estimated difference (95% CI) 0.37 (-0.69 to 1.42), p=0.49. There was no difference in time until resolution of symptoms: mean (SD) 5.96 (4.47) days for rNHF vs 6.42 (4.09) days for 'sham'; estimated difference (95% CI) 1.02 (0.75 to 1.38), p=0.91. There were no serious adverse events related to the study treatments. CONCLUSIONS: This well-powered, single-blind randomised controlled trial does not provide evidence that 5 days of rNHF (100% humidified air heated to 41°C delivered at 35 L/min for 2 hours daily) reduces common cold symptom severity or duration. However, investigation of rNHF in the treatment of influenza is warranted. TRIAL REGISTRATION NUMBER: ACTRN12617001340325.

Protocol for a randomised, single-blind, two-arm, parallel-group controlled trial of the efficacy of rhinothermy delivered by nasal high flow therapy in the treatment of the common cold.

INTRODUCTION: The common cold is the most common infectious disease affecting humans. It is usually a self-limiting disease; however, the common cold can cause significant morbidity and has a substantial economic impact on society. Human rhinoviruses (HRVs), which cause up to two-thirds of colds, have temperature-dependent replication and most HRV strains replicate optimally at 33°C. Delivery of heated, humidified air to the upper airways has the potential to reduce viral replication, but evidence of the effectiveness of this treatment of the common cold is inconclusive. We plan to test the hypothesis that delivery of humidified air heated to 41°C at high flow, nasal high flow rhinothermy (rNHF), for 2 hours daily for five days is more effective in reducing common cold symptom severity and duration than five days of 'sham' rhinothermy. METHODS AND ANALYSIS: This is a randomised, single-blind, parallel-group trial comparing rNHF to 'sham' rhinothermy in the treatment of common cold. We plan to recruit 170 participants within 48 hours of the onset of symptoms of common cold and randomise them 1:1 to receive one of the two treatments for five days. The study duration is 14 days, which includes clinic visits on the first day of randomisation and four days post-randomisation, and a phone call on the 14th day. Participants will complete daily symptom diaries which include a symptom score, the Modified Jackson Score (MJS). The primary outcome is the MJS after four days. ETHICS AND DISSEMINATION: New Zealand Ethics Registration: 17/STH/174. Results will be published in a peer-reviewed medical journal, presented at academic meetings, and reported to participants. TRIAL REGISTRATION NUMBER: U1111-1194-4345 and ACTRN12617001340325; Pre-results.