Automaticversusmanual oxygen administration in the emergency department

Automated oxygen titration with non-invasive ventilation in hypoxaemic adults with cardiorespiratory disease: a randomised cross-over trial

BACKGROUND

Closed-loop oxygen control systems automatically adjust the fraction of inspired oxygen (FiO2) to maintain oxygen saturation (SpO2) within a predetermined target range. Their performance with low and high-flow oxygen therapies, but not with non-invasive ventilation, has been established. We compared the effect of automated oxygen on achieving and maintaining a target SpO2 range with nasal high flow (NHF), bilevel positive airway pressure (bilevel) and continuous positive airway pressure (CPAP), in stable hypoxaemic patients with chronic cardiorespiratory disease.

METHODS

In this open-label, three-way cross-over trial, participants with resting hypoxaemia (n=12) received each of NHF, bilevel and CPAP treatments, in random order, with automated oxygen titrated for 10 min, followed by 36 min of standardised manual oxygen adjustments. The primary outcome was the time taken to reach target SpO2 range (92%-96%). Secondary outcomes included time spent within target range and physiological responses to automated and manual oxygen adjustments.

RESULTS

Two participants were randomised to each of six possible treatment orders. During automated oxygen control (n=12), the mean (±SD) time to reach target range was 114.8 (±87.9), 56.6 (±47.7) and 67.3 (±61) seconds for NHF, bilevel and CPAP, respectively, mean difference 58.3 (95% CI 25.0 to 91.5; p=0.002) and 47.5 (95% CI 14.3 to 80.7; p=0.007) seconds for bilevel and CPAP versus NHF, respectively. Proportions of time spent within target range were 68.5% (±16.3), 65.6% (±28.7) and 74.7% (±22.6) for NHF, bilevel and CPAP, respectively.Manually increasing, then decreasing, the FiO2 resulted in similar increases and then decreases in SpO2 and transcutaneous carbon dioxide (PtCO2) with NHF, bilevel and CPAP.

CONCLUSION

The target SpO2 range was achieved more quickly when automated oxygen control was initiated with bilevel and CPAP compared with NHF while time spent within the range across the three therapies was similar. Manually changing the FiO2 had similar effects on SpO2 and PtCO2 across each of the three therapies.

TRIAL REGISTRATION NUMBER

ACTRN12622000433707.

Effect of automated titration of oxygen on time spent in a prescribed oxygen saturation range in adults in the ICU after cardiac surgery

Objective

The objective of this study was to determine whether automated titration of the fraction of inspired oxygen (FiO2) increases the time spent with oxygen saturation (SpO2) within a predetermined target SpO2 range compared with manually adjusted high-flow oxygen therapy in postoperative cardiac surgical patients managed in the intensive care unit (ICU).

Design

Single-centre, open-label, randomised clinical trial.

Setting

Tertiary centre ICU.

Participants

Recently extubated adults following elective cardiac surgery who required supplemental oxygen.

Interventions

Automatically adjusted FiO2 (using an automated oxygen control system) compared with manual FiO2 titration, until cessation of oxygen therapy, ICU discharge, or 24 h (whichever was sooner).

Main outcome measures

The primary outcome was the proportion of time receiving oxygen therapy with the SpO2 in a SpO2 target range of 92-96 %.

Results

Among 65 participants, the percentage of time per patient spent in the target SpO2 range was a median of 97.7 % (interquartile range: 87.9-99.2 %) and 91.3 % (interquartile range: 77.1-96.1 %) in the automated (n = 28) and manual (n = 28) titration groups, respectively. The estimated effect of automated FiO2, compared to manual FiO2 titration, was to increase the percentage of time spent in the target range by a median of 4.8 percentage points (95 % confidence interval: 1.6 to 10.3 percentage points, p = 0.01).

Conclusion

In patients recently extubated after cardiac surgery, automated FiO2 titration significantly increased time spent in a target SpO2 range of 92-96 % compared to manual FiO2 titration.

Innovative Predictive Approach towards a Personalized Oxygen Dosing System

Despite the large impact chronic obstructive pulmonary disease (COPD) that has on the population, the implementation of new technologies for diagnosis and treatment remains limited. Current practices in ambulatory oxygen therapy used in COPD rely on fixed doses overlooking the diverse activities which patients engage in. To address this challenge, we propose a software architecture aimed at delivering patient-personalized edge-based artificial intelligence (AI)-assisted models that are built upon data collected from patients' previous experiences along with an evaluation function. The main objectives reside in proactively administering precise oxygen dosages in real time to the patient (the edge), leveraging individual patient data, previous experiences, and actual activity levels, thereby representing a substantial advancement over conventional oxygen dosing. Through a pilot test using vital sign data from a cohort of five patients, the limitations of a one-size-fits-all approach are demonstrated, thus highlighting the need for personalized treatment strategies. This study underscores the importance of adopting advanced technological approaches for ambulatory oxygen therapy.

Closed-loop ventilation

PURPOSE OF REVIEW

The last 25 years have seen considerable development in modes of closed-loop ventilation and there are now several of them commercially available. They not only offer potential benefits for the individual patient, but may also improve the organization within the intensive care unit (ICU). Clinicians are showing both greater interest and willingness to address the issues of a caregiver shortage and overload of bedside work in the ICU. This article reviews the clinical benefits of using closed-loop ventilation modes, with a focus on control of oxygenation, lung protection, and weaning.

RECENT FINDINGS

Closed-loop ventilation modes are able to maintain important physiological variables, such as oxygen saturation measured by pulse oximetry, tidal volume (VT), driving pressure (ΔP), and mechanical power (MP), within target ranges aimed at ensuring continuous lung protection. In addition, these modes adapt the ventilator support to the patient's needs, promoting diaphragm activity and preventing over-assistance. Some studies have shown the potential of these modes to reduce the duration of both weaning and mechanical ventilation.

SUMMARY

Recent studies have primarily demonstrated the safety, efficacy, and feasibility of using closed-loop ventilation modes in the ICU and postsurgery patients. Large, multicenter randomized controlled trials are needed to assess their impact on important short- and long-term clinical outcomes, the organization of the ICU, and cost-effectiveness.

Automated Oxygen Administration Alleviates Dyspnea in Patients Admitted with Acute Exacerbation of COPD: A Randomized Controlled Trial

Objective

Devices for Automated Oxygen Administration (AOA) have been developed to optimize the therapeutic benefit of oxygen supplementation. We aimed to investigate the effect of AOA on multidimensional aspects of dyspnea and as-needed consumption of opioids and benzodiazepines, as opposed to conventional oxygen therapy, in hospitalized patients with Acute Exacerbation of COPD (AECOPD).

Method and Patients

A multicenter randomized controlled trial across five respiratory wards in the Capital Region of Denmark. Patients admitted with AECOPD (n=157) were allocated 1:1 to either AOA (O2matic Ltd), a closed loop device automatically delivering oxygen according to the patient's peripheral oxygen saturation (SpO₂), or conventional nurse-administered oxygen therapy. Oxygen flows and SpO₂ levels were measured by the O2matic device in both groups, while dyspnea, anxiety, depression, and COPD symptoms were accessed by Patient Reported Outcomes.

Results

Of the 157 randomized patients, 127 had complete data for the intervention. The AOA reduced patients' perception of overall unpleasantness significantly on the Multidimensional Dyspnea Profile (MDP) with a difference in medians of -3 (p=0.003) between the intervention group (n=64) and the control group (n=63). The AOA also provided a significant between group difference in all single items within the sensory domain of the MDP (all p-values≤0.05) as well as in the Visual Analogue Scale - Dyspnea (VAS-D) within the past three days (p=0.013). All between group differences exceeded the Minimal Clinical Important Difference of the MDP and VAS-D, respectively. AOA did not seem to have an impact on the emotional response domain of the MDP, the COPD Assessment Test, the Hospital Anxiety and Depression Scale, or use of as-needed opioids and/or benzodiazepines (all p-values>0.05).

Conclusion

AOA reduces both breathing discomfort and physical perception of dyspnea in patients admitted with AECOPD but did not seem to impact the emotional status or other COPD symptoms.

Assessment of Racial and Ethnic Differences in Oxygen Supplementation Among Patients in the Intensive Care Unit

IMPORTANCE

Pulse oximetry (SpO2) is routinely used for transcutaneous monitoring of blood oxygenation, but it can overestimate actual oxygenation. This is more common in patients of racial and ethnic minority groups. The extent to which these discrepancies are associated with variations in treatment is not known.

OBJECTIVE

To determine if there are racial and ethnic disparities in supplemental oxygen administration associated with inconsistent pulse oximeter performance.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study was based on the Medical Information Mart for Intensive Care (MIMIC)-IV critical care data set. Included patients were documented with a race and ethnicity as Asian, Black, Hispanic, or White and were admitted to the intensive care unit (ICU) for at least 12 hours before needing advanced respiratory support, if any. Oxygenation levels and nasal cannula flow rates for up to 5 days from ICU admission or until the time of intubation, noninvasive positive pressure ventilation, high-flow nasal cannula, or tracheostomy were analyzed.

MAIN OUTCOMES AND MEASURES

The primary outcome was time-weighted average supplemental oxygen rate. Covariates included race and ethnicity, sex, SpO2-hemoglobin oxygen saturation discrepancy, data duration, number and timing of blood gas tests on ICU days 1 to 3, partial pressure of carbon dioxide, hemoglobin level, average respiratory rate, Elixhauser comorbidity scores, and need for vasopressors or inotropes.

RESULTS

This cohort included 3069 patients (mean [SD] age, 66.9 [13.5] years; 83 were Asian, 207 were Black, 112 were Hispanic, 2667 were White). In a multivariable linear regression, Asian (coefficient, 0.602; 95% CI, 0.263 to 0.941; P = .001), Black (coefficient, 0.919; 95% CI, 0.698 to 1.140; P < .001), and Hispanic (coefficient, 0.622; 95% CI, 0.329 to 0.915; P < .001) race and ethnicity were all associated with a higher SpO2 for a given hemoglobin oxygen saturation. Asian (coefficient, -0.291; 95% CI, -0.546 to -0.035; P = .03), Black (coefficient, -0.294; 95% CI, -0.460 to -0.128; P = .001), and Hispanic (coefficient, -0.242; 95% CI, -0.463 to -0.020; P = .03) race and ethnicity were associated with lower average oxygen delivery rates. When controlling for the discrepancy between average SpO2 and average hemoglobin oxygen saturation, race and ethnicity were not associated with oxygen delivery rate. This discrepancy mediated the effect of race and ethnicity (-0.157; 95% CI, -0.250 to -0.057; P = .002).

CONCLUSIONS AND RELEVANCE

In this cohort study, Asian, Black, and Hispanic patients received less supplemental oxygen than White patients, and this was associated with differences in pulse oximeter performance, which may contribute to known race and ethnicity-based disparities in care.

Closed-loop oxygen control improves oxygen therapy in acute hypoxemic respiratory failure patients under high flow nasal oxygen: a randomized cross-over study (the HILOOP study)

Background

We aimed to assess the efficacy of a closed-loop oxygen control in critically ill patients with moderate to severe acute hypoxemic respiratory failure (AHRF) treated with high flow nasal oxygen (HFNO).

Methods

In this single-centre, single-blinded, randomized crossover study, adult patients with moderate to severe AHRF who were treated with HFNO (flow rate ≥ 40 L/min with FiO₂ ≥ 0.30) were randomly assigned to start with a 4-h period of closed-loop oxygen control or 4-h period of manual oxygen titration, after which each patient was switched to the alternate therapy. The primary outcome was the percentage of time spent in the individualized optimal SpO₂ range.

Results

Forty-five patients were included. Patients spent more time in the optimal SpO₂ range with closed-loop oxygen control compared with manual titrations of oxygen (96.5 [93.5 to 98.9] % vs. 89 [77.4 to 95.9] %; p < 0.0001) (difference estimate, 10.4 (95% confidence interval 5.2 to 17.2). Patients spent less time in the suboptimal range during closed-loop oxygen control, both above and below the cut-offs of the optimal SpO₂ range, and less time above the suboptimal range. Fewer number of manual adjustments per hour were needed with closed-loop oxygen control. The number of events of SpO₂ < 88% and < 85% were not significantly different between groups.

Conclusions

Closed-loop oxygen control improves oxygen administration in patients with moderate-to-severe AHRF treated with HFNO, increasing the percentage of time in the optimal oxygenation range and decreasing the workload of healthcare personnel. These results are especially relevant in a context of limited oxygen supply and high medical demand, such as the COVID-19 pandemic.

Trial registration The HILOOP study was registered at www.clinicaltrials.gov under the identifier NCT04965844.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-03970-w.

Thoracic Society of Australia and New Zealand Position Statement on Acute Oxygen Use in Adults: 'Swimming between the flags'

Oxygen is a life-saving therapy but, when given inappropriately, may also be hazardous. Therefore, in the acute medical setting, oxygen should only be given as treatment for hypoxaemia and requires appropriate prescription, monitoring and review. This update to the Thoracic Society of Australia and New Zealand (TSANZ) guidance on acute oxygen therapy is a brief and practical resource for all healthcare workers involved with administering oxygen therapy to adults in the acute medical setting. It does not apply to intubated or paediatric patients. Recommendations are made in the following six clinical areas: assessment of hypoxaemia (including use of arterial blood gases); prescription of oxygen; peripheral oxygen saturation targets; delivery, including non-invasive ventilation and humidified high-flow nasal cannulae; the significance of high oxygen requirements; and acute hypercapnic respiratory failure. There are three sections which provide (1) a brief summary, (2) recommendations in detail with practice points and (3) a detailed explanation of the reasoning and evidence behind the recommendations. It is anticipated that these recommendations will be disseminated widely in structured programmes across Australia and New Zealand.

Patients' Perspective on Automated Oxygen Administration during Hospitalization for Acute Exacerbation of Chronic Obstructive Pulmonary Disease: A Qualitative Study Nested in a Randomized Controlled Trial

Recently, health technology systems offering monitoring of the peripheral oxygen saturation level and automated oxygen administration (AOA) have emerged. AOA has been shown to reduce duration of hypoxemia and the length of hospital stay, but the patients' perspective on AOA has not been investigated. This qualitative study, based on the interpretive description methodology, aimed to explore how patients hospitalized with exacerbation of chronic obstructive pulmonary disease (COPD) experience being treated with AOA. Eighteen patients treated with AOA were included in the study. Data was collected during admission or in the patients' homes using semi-structured interviews focusing on patients' experiences of AOA using the word "robot" as used by patients. The findings revealed two themes "adaptation of behavior to the robot" and "robots can make patients feel safe but not cared for" and six subthemes. Our findings illustrate how patients were willing to compromise their own therapy and thereby safety by avoiding behavior triggering AOA alarms and disturbing their fellow patients and the health care professionals. Adherence, defined as patients' consistency in taking their medications as prescribed, becomes an important point of attention for health professionals when applying individualized robotic therapies such as AOA to patients with COPD. To support patients in the process of managing adherence to therapeutic technology, we propose a person-centered care approach that, through education and communication with the patients, generates an understanding of how they can self-manage AOA and its alarms without activating avoiding behavior that threatens their treatment and recovery.

German S3 Guideline: Oxygen Therapy in the Acute Care of Adult Patients

BACKGROUND

Oxygen (O2) is a drug with specific biochemical and physiological properties, a range of effective doses and may have side effects. In 2015, 14% of over 55,000 hospital patients in the UK were using oxygen. 42% of patients received this supplemental oxygen without a valid prescription. Health care professionals are frequently uncertain about the relevance of hypoxemia and have low awareness about the risks of hyperoxemia. Numerous randomized controlled trials about targets of oxygen therapy have been published in recent years. A national guideline is urgently needed.

METHODS

A national S3 guideline was developed and published within the Program for National Disease Management Guidelines (AWMF) with participation of 10 medical associations. A literature search was performed until February 1, 2021, to answer 10 key questions. The Oxford Centre for Evidence-Based Medicine (CEBM) System ("The Oxford 2011 Levels of Evidence") was used to classify types of studies in terms of validity. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for assessing the quality of evidence and for grading guideline recommendation, and a formal consensus-building process was performed.

RESULTS

The guideline includes 34 evidence-based recommendations about indications, prescription, monitoring and discontinuation of oxygen therapy in acute care. The main indication for O2 therapy is hypoxemia. In acute care both hypoxemia and hyperoxemia should be avoided. Hyperoxemia also seems to be associated with increased mortality, especially in patients with hypercapnia. The guideline provides recommended target oxygen saturation for acute medicine without differentiating between diagnoses. Target ranges for oxygen saturation are based depending on ventilation status risk for hypercapnia. The guideline provides an overview of available oxygen delivery systems and includes recommendations for their selection based on patient safety and comfort.

CONCLUSION

This is the first national guideline on the use of oxygen in acute care. It addresses health care professionals using oxygen in acute out-of-hospital and in-hospital settings.

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.

[German S3 Guideline - Oxygen Therapy in the Acute Care of Adult Patients]

BACKGROUND

 Oxygen (O₂) is a drug with specific biochemical and physiologic properties, a range of effective doses and may have side effects. In 2015, 14 % of over 55 000 hospital patients in the UK were using oxygen. 42 % of patients received this supplemental oxygen without a valid prescription. Healthcare professionals are frequently uncertain about the relevance of hypoxemia and have low awareness about the risks of hyperoxemia. Numerous randomized controlled trials about targets of oxygen therapy have been published in recent years. A national guideline is urgently needed.

METHODS

 A S3-guideline was developed and published within the Program for National Disease Management Guidelines (AWMF) with participation of 10 medical associations. Literature search was performed until Feb 1st 2021 to answer 10 key questions. The Oxford Centre for Evidence-Based Medicine (CEBM) System ("The Oxford 2011 Levels of Evidence") was used to classify types of studies in terms of validity. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used and for assessing the quality of evidence and for grading guideline recommendation and a formal consensus-building process was performed.

RESULTS

 The guideline includes 34 evidence-based recommendations about indications, prescription, monitoring and discontinuation of oxygen therapy in acute care. The main indication for O₂ therapy is hypoxemia. In acute care both hypoxemia and hyperoxemia should be avoided. Hyperoxemia also seems to be associated with increased mortality, especially in patients with hypercapnia. The guideline provides recommended target oxygen saturation for acute medicine without differentiating between diagnoses. Target ranges for oxygen saturation are depending on ventilation status risk for hypercapnia. The guideline provides an overview of available oxygen delivery systems and includes recommendations for their selection based on patient safety and comfort.

CONCLUSION

 This is the first national guideline on the use of oxygen in acute care. It addresses healthcare professionals using oxygen in acute out-of-hospital and in-hospital settings. The guideline will be valid for 3 years until June 30, 2024.

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).

Acute oxygen use in hospitalised patients with chronic obstructive pulmonary disease is guideline discordant

Ample evidence supports an association between acute oxygen over-administration and harm. Australian and international guidelines consistently recommend lower oxygen saturation aims in populations with chronic obstructive pulmonary disease (COPD). We assessed adherence to acute oxygen use guidelines and outcomes in hospitalised patients with COPD at a large Australian metropolitan hospital network.

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.

Automatic oxygen flow titration in spontaneously breathing children: An open-label randomized controlled pilot study

INTRODUCTION

When children require supplemental oxygen due to acute hypoxemic respiratory distress (AHRD), manual control of the oxygen flow is often difficult and time-consuming, and carries the risk of unrecognized hypoxia and hyperoxia. To date, no automatic oxygen titration system has been developed and evaluated in spontaneously breathing children.

METHODS

Children between 1 month and 15 years of age receiving supplemental oxygen due to AHRD were recruited within 24 hours following the onset of the O₂ administration in a French University Department of Paediatrics. Patients were randomized to receive either automated oxygen administration using the FreeO2 device, or conventional manual oxygen administration over a maximum period of 6 hours. Stratification was performed to classify the patients into two age groups: 1 month to 2 years of age and 2 to 15 years of age. The primary outcome was % time spent within the SpO₂ target range (92%-98%).

RESULTS

60 patients (30 infants, 30 children) were randomized and 55 could be analyzed for the primary outcome (28 automated, 27 manual). The automated O₂ delivery using the FreeO2 device significantly increased the time spent within the predefined SpO₂ range (94.6% ± 6% vs 76.3% ± 22%, difference [95% confidence interval {CI}] 18.4 [10.1; 26.7]) with less time spent with hypoxemia (1% ± 1.1% vs 15.1% ± 21.8%, difference [95% CI] -14.4 [-22.2; -6.7]). This difference was greater among (2-15 years of age) children, compared to (1 month-2 years of age) infants.

CONCLUSIONS

The present randomized controlled pilot study indicates that the tested automated closed-loop O₂ titration technology was safe and yielded improved oxygen parameters among spontaneously breathing children. Based on our pilot data, a full randomized controlled trial will be required to verify the potential clinical benefits.

Automatic oxygen titration with O2matic® to patients admitted with COVID-19 and hypoxemic respiratory failure

Introduction

Patients with coronavirus disease (COVID-19) and pneumonitis often have hypoxemic respiratory failure and a need of supplementary oxygen. Guidelines recommend controlled oxygen, for most patients with a recommended interval of SpO₂ between 92 and 96%. We aimed to determine if closed-loop control of oxygen was feasible in patients with COVID-19 and could maintain SpO₂ in the specified interval.

Methods

Patients were prospectively enrolled in an observational study on a medical ward dedicated to patients with COVID-19. Closed-loop controlled oxygen was delivered by O2matic® which can deliver 0-15 liters/min and adjusts flow every second based on 15 seconds averaging of SpO₂ measured by pulse oximetry. Lung function parameters were measured at admission.

Results

Fifteen patients (six women, nine men) participated in the study. Average age was 72 years. Lung function was severely impaired with FEV₁, FVC and PEF reduced to approximately 50%. The average stay on the ward was 3.2 days and O2matic was used on average for 66 hours, providing 987 hours of observation. O2matic maintained SpO₂ in the desired interval for 82.9% of the time. Time with SpO₂ > 2% below interval was 5.1% and time with SpO₂ > 2% above interval was 0.6%.

Conclusion

Closed-loop control of oxygen to patients with COVID-19 is feasible and can maintain SpO₂ in the specified interval in the majority of time. Closed-loop automated control could be of particular benefit for patients in isolation with decreased visibility, surveillance and monitoring. Further studies must examine the clinical benefits.

Automated closed-loop versus standard manual oxygen administration after major abdominal or thoracic surgery: an international multicentre randomised controlled study

Introduction

Hypoxaemia and hyperoxaemia may occur after surgery, with related complications. This multicentre randomised trial evaluated the impact of automated closed-loop oxygen administration after high-risk abdominal or thoracic surgeries in terms of optimising the oxygen saturation measured by pulse oximetry time within target range.

Methods

After extubation, patients with an intermediate to high risk of post-operative pulmonary complications were randomised to “standard” or “automated” closed-loop oxygen administration. The primary outcome was the percentage of time within the oxygenation range, during a 3-day frame. The secondary outcomes were the time with hypoxaemia and hyperoxaemia under oxygen.

Results

Among the 200 patients, time within range was higher in the automated group, both initially (≤3 h; 91.4±13.7% versus 40.2±35.1% of time, difference +51.0% (95% CI −42.8–59.2%); p<0.0001) and during the 3-day period (94.0±11.3% versus 62.1±23.3% of time, difference +31.9% (95% CI 26.3–37.4%); p<0.0001). Periods of hypoxaemia were reduced in the automated group (≤3 days; 32.6±57.8 min (1.2±1.9%) versus 370.5±594.3 min (5.0±11.2%), difference −10.2% (95% CI −13.9–−6.6%); p<0.0001), as well as hyperoxaemia under oxygen (≤3 days; 5.1±10.9 min (4.8±11.2%) versus 177.9±277.2 min (27.0±23.8%), difference −22.0% (95% CI −27.6–−16.4%); p<0.0001). Kaplan–Meier analysis depicted a significant difference in terms of hypoxaemia (p=0.01) and severe hypoxaemia (p=0.0003) occurrence between groups in favour of the automated group. 25 patients experienced hypoxaemia for >10% of the entire monitoring time during the 3 days within the standard group, as compared to the automated group (p<0.0001).

Conclusion

Automated closed-loop oxygen administration promotes greater time within the oxygenation target, as compared to standard manual administration, thus reducing the occurrence of hypoxaemia and hyperoxaemia.

COVID-19: Pulse oximeters in the spotlight

From home to intensive care units, innovations in pulse oximetry are susceptible to improve the monitoring and management of patients developing acute respiratory failure, and particularly those with the coronavirus disease 2019 (COVID-19). They include self-monitoring of oxygen saturation (SpO₂) from home, continuous wireless SpO₂ monitoring on hospital wards, and the integration of SpO₂ as the input variable for closed-loop oxygen administration systems. The analysis of the pulse oximetry waveform may help to quantify respiratory efforts and prevent intubation delays. Tracking changes in the peripheral perfusion index during a preload-modifying maneuver may be useful to predict preload responsiveness and rationalize fluid therapy.

Oxygen therapy in the pre-hospital setting for acute exacerbations of chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a global leading cause of morbidity and mortality, characterised by acute deterioration in symptoms. During these exacerbations, people are prone to developing alveolar hypoventilation, which may be partly caused by the administration of high inspired oxygen concentrations.

OBJECTIVES

To determine the effect of different inspired oxygen concentrations ("high flow" compared to "controlled") in the pre-hospital setting (prior to casualty/emergency department) on outcomes for people with acute exacerbations of COPD (AECOPD).

SEARCH METHODS

The Cochrane Airways Group Specialised Register, reference lists of articles and online clinical trial databases were searched. Authors of identified randomised controlled trials (RCTs) were also contacted for details of other relevant published and unpublished studies. The most recent search was conducted on 16 September 2019.

SELECTION CRITERIA

We included RCTs comparing oxygen therapy at different concentrations or oxygen therapy versus placebo in the pre-hospital setting for treatment of AECOPD.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The primary outcome was all-cause and respiratory-related mortality.

MAIN RESULTS

The search identified a total of 824 citations; one study was identified for inclusion and two studies are awaiting classification. The 214 participants involved in the included study were adults with AECOPD, receiving treatment by paramedics en route to hospital. The mean age of participants was 68 years. A reduction in pre/in-hospital mortality was observed in favour of the titrated oxygen group (two deaths in the titrated oxygen group compared to 11 deaths in the high-flow control arm; risk ratio (RR) 0.22, 95% confidence interval (CI) 0.05 to 0.97; 214 participants). This translates to an absolute effect of 94 per 1000 (high-flow oxygen) compared to 21 per 1000 (titrated oxygen), and a number needed to treat for an additional beneficial outcome (NNTB) of 14 (95% CI 12 to 355) with titrated oxygen therapy. Other than mortality, no other adverse events were reported in the included study. Wide confidence intervals were observed between groups for arterial blood gas (though this may be confounded by protocol infidelity in the included study for this outcome measure), treatment failure requiring invasive or non-invasive ventilation or hospital utilisation. No data were reported for quality of life, lung function or dyspnoea. Risk of bias within the included study was largely unclear, though there was high risk of bias in domains relating to performance and attrition bias. We judged the evidence to be of low certainty, according to GRADE criteria.

AUTHORS' CONCLUSIONS

The one included study found a reduction in pre/in-hospital mortality for the titrated oxygen arm compared to the high-flow control arm. However, the paucity of evidence somewhat limits the reliability of these findings and generalisability to other settings. There is a need for robust, well-designed RCTs to further investigate the effect of oxygen therapies in the pre-hospital setting for people with AECOPD.

Automated Oxygen Delivery in Hospitalized Patients with Acute Respiratory Failure: A Pilot Study

Background and Objectives

Despite its' proven benefits, oxygen therapy may be complicated with potential adverse events such as hypoxemia or hyperoxia-driven hypercapnia. Automated oxygen delivery systems may aid in avoiding these complications. The scope of the present study is to test the efficacy and safety of a new automated oxygen delivery device.

Methods

This study included 23 patients with acute respiratory failure (ARF) hospitalized in the Respiratory Medicine Department of the University Hospital of Larissa. Both patients with purely hypoxemic or hypercapnic ARF were included. Automated oxygen administration was performed with Digital Oxygen Therapy, a new closed-loop system designed to automatically adjust oxygen flow according to target oxygen saturation (SpO₂) of 88-92% for hypercapnic patients and 92-96% for purely hypoxemic patients with ARF. The device was applied for 4 hours. Arterial blood gas analysis was performed at 1 hour and 3 hours following the device application.

Results

Mean age was 72.91 ± 13.91 years. Twelve patients were male, and 11 were female. The majority of patients suffered from hypercapnic respiratory failure (n=13, 56.5%). At 1 hour and 3 hours, SpO₂ and PaO₂ displayed excellent correlation (p < 0.001, r = 0.943, and p < 0.001, r = 0.954, respectively). We did not observe any adverse events associated with the device.

Conclusions

Our results indicate that automated oxygen treatment is feasible and safe in hospitalized patients with acute respiratory failure. Further studies are required in order to assess the long-term effects of automated oxygen delivery systems.

Automated oxygen administration versus conventional oxygen therapy after major abdominal or thoracic surgery: study protocol for an international multicentre randomised controlled study

INTRODUCTION

Hypoxemia and hyperoxia may occur after surgery with potential related complications. The FreeO₂ PostOp trial is a prospective, multicentre, randomised controlled trial that evaluates the clinical impact of automated O₂ administration versus conventional O₂ therapy after major abdominal or thoracic surgeries. The study is powered to demonstrate benefits of automated oxygen titration and weaning in term of oxygenation, which is an important surrogate for complications after such interventions.

METHODS AND ANALYSIS

After extubation, patients are randomly assigned to the Standard (manual O₂ administration) or FreeO₂ group (automated closed-loop O₂ administration). Stratification is performed for the study centre and a medical history of chronic obstructive pulmonary disease (COPD). Primary outcome is the percentage of time spent in the target zone of oxygen saturation, during a 3-day time frame. In both groups, patients will benefit from continuous oximetry recordings. The target zone of oxygen saturation is SpO₂=88%-92% for patients with COPD and 92%-96% for patients without COPD. Secondary outcomes are the nursing workload assessed by the number of manual O₂ flow adjustments, the time spent with severe desaturation (SpO₂ <85%) and hyperoxia area (SpO₂ >98%), the time spent in a hyperoxia area (SpO₂ >98%), the VO₂, the duration of oxygen administration during hospitalisation, the frequency of use of mechanical ventilation (invasive or non-invasive), the duration of the postrecovery room stay, the hospitalisation length of stay and the survival rate.

ETHICS AND DISSEMINATION

The FreeO₂ PostOp study is conducted in accordance with the declaration of Helsinki and was registered on 11 September 2015 (http://www.clinicaltrials.gov). First patient inclusion was performed on 14 January 2016. The results of the study will be presented at academic conferences and submitted to peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT02546830.

Automated oxygen control with O2matic® during admission with exacerbation of COPD

PURPOSE

It is a challenge to control oxygen saturation (SpO2) in patients with exacerbations of COPD during admission. We tested a newly developed closed-loop system, O2matic®, and its ability to keep SpO2 within a specified interval compared with manual control by nursing staff.

PATIENTS AND METHODS

We conducted a crossover trial with patients admitted with an exacerbation of COPD and hypoxemia (SpO2 ≤88% on room air). Patients were monitored with continuous measurement of SpO2. In random order, they had 4 hours with manually controlled oxygen and 4 hours with oxygen delivery controlled by O2matic. Primary outcome was time within a prespecified SpO2 target interval. Secondary outcomes were time with SpO2 <85%, time with SpO2 below target but not <85%, and time with SpO2 above target.

RESULTS

Twenty patients were randomized and 19 completed the study. Mean age was 72.4 years and mean FEV1 was 0.72 L (33% of predicted). Patients with O2matic-controlled treatment were within the SpO2 target interval in 85.1% of the time vs 46.6% with manually controlled treatment (P<0.001). Time with SpO2 <85% was 1.3% with O2matic and 17.9% with manual control (P=0.01). Time with SpO2 below target but not <85% was 9.0% with O2matic and 25.0% with manual control (P=0.002). Time with SpO2 above target was not significantly different between treatments (4.6% vs 10.5%, P=0.2). Patients expressed high confidence and a sense of safety with automatic oxygen delivery.

CONCLUSION

O2matic was able to effectively control SpO2 for patients admitted with an exacerbation of COPD. O2matic was significantly better than manual control to maintain SpO2 within target interval and to reduce time with unintended hypoxemia.

New Perspectives in Oxygen Therapy Titration: Is Automatic Titration the Future?

Oxygen therapy, like all technology-based treatments, is continuously evolving. There are no doubts as to its effectiveness in the treatment of acute and respiratory failure in different clinical scenarios. However, the dosing guidelines for oxygen therapy are not as strict as for other treatments. The use of higher than necessary flows over excessively long periods, derived from the clinician's perception of it as a 'life-saving treatment with few side effects', has led to a rather liberal use of this intervention, despite evidence that overuse and suboptimal adjustment can be harmful. The titration of oxygen therapy, which is traditionally performed manually, has been shown to be beneficial. Recently, new devices have been developed that automatically adjust oxygen flow rates to the needs of each patient, in order to maintain stable oxygen saturation levels. These closed-loop oxygen supply systems can potentially reduce medical error, improve morbidity and mortality, and reduce care costs. Familiarizing the medical community with these technological advances will improve awareness of the risks of the inappropriate use of oxygen therapy. The aim of this paper is to provide an update of recent developments in oxygen therapy titration.