ABSTRACT
Background: The concentration of exhaled octane has been postulated as a reliable biomarker for acute respiratory distress syndrome (ARDS) using metabolomics analysis with gas chromatography and mass spectrometry (GC-MS). A point-of-care (POC) breath test was developed in recent years to accurately measure octane at the bedside. The aim of the present study was to validate the diagnostic accuracy of exhaled octane for ARDS using a POC breath test in invasively ventilated intensive care unit (ICU) patients. Methods: This was an observational cohort study of consecutive patients receiving invasive ventilation for at least 24â h, recruited in two university ICUs. GC-MS and POC breath tests were used to quantify the exhaled octane concentration. ARDS was assessed by three experts following the Berlin definition and used as the reference standard. The area under the receiver operating characteristic curve (AUC) was used to assess diagnostic accuracy. Results: 519 patients were included and 190 (37%) fulfilled the criteria for ARDS. The median (interquartile range) concentration of octane using the POC breath test was not significantly different between patients with ARDS (0.14 (0.05-0.37)â ppb) and without ARDS (0.11 (0.06-0.26)â ppb; p=0.64). The AUC for ARDS based on the octane concentration in exhaled breath using the POC breath test was 0.52 (95% CI 0.46-0.57). Analysis of exhaled octane with GC-MS showed similar results. Conclusions: Octane in exhaled breath has insufficient diagnostic accuracy for ARDS. This disqualifies the use of octane as a biomarker in the diagnosis of ARDS and challenges most of the research performed up to now in the field of exhaled breath metabolomics.
ABSTRACT
BACKGROUND: Childhood asthma is imposing a great financial burden on the pediatric health care system. Asthma costs are directly related to the level of asthma control. A substantial part of these costs may be preventable by the timely and adequate assessment of asthma deterioration in daily life and proper asthma management. The use of eHealth technology may assist such timely and targeted medical anticipation. OBJECTIVE: This paper describes the Ambulatory Pediatric Asthma Care (ALPACA) study protocol to investigate the effectiveness of an eHealth intervention consisting of remote patient monitoring and teleconsultation integrated into the daily clinical care of pediatric patients with asthma. This intervention aims to reduce health care utilization and costs and improve health outcomes compared to a control group that receives standard care. In addition, this study aims to improve future eHealth pediatric asthma care by gaining insights from home-monitoring data. METHODS: This study is a prospective randomized controlled effectiveness trial. A total of 40 participants will be randomized to either 3 months of eHealth care (intervention group) or standard care (control group). The eHealth intervention consists of remote patient monitoring (spirometry, pulse oximetry, electronic medication adherence tracking, and asthma control questionnaire) and web-based teleconsultation (video sharing, messages). All participants will have a 3-month follow-up with standard care to evaluate whether the possible effects of eHealth care are longer lasting. During the entire study and follow-up period, all participants will use blinded observational home monitoring (sleep, cough/wheeze sounds, air quality in bedroom) as well. RESULTS: This study was approved by the Medical Research Ethics Committees United. Enrollment began in February 2023, and the results of this study are expected to be submitted for publication in July 2024. CONCLUSIONS: This study will contribute to the existing knowledge on the effectiveness of eHealth interventions that combine remote patient monitoring and teleconsultation for health care utilization, costs, and health outcomes. Furthermore, the observational home-monitoring data can contribute to improved identification of early signs of asthma deterioration in pediatric patients. Researchers and technology developers could use this study to guide and improve eHealth development, while health care professionals, health care institutions, and policy makers may employ our results to make informed decisions to steer toward high-quality, efficient pediatric asthma care. TRIAL REGISTRATION: ClinicalTrials.gov NCT05517096; https://clinicaltrials.gov/ct2/show/NCT05517096. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/45585.
ABSTRACT
BACKGROUND: Acute respiratory distress syndrome (ARDS) is currently diagnosed by the Berlin Definition. Diagnosis is subjective and often late. Untargeted metabolomics analysis of exhaled breath with gas chromatography and mass spectrometry (GC-MS) showed that the breath concentration of octane has a high diagnostic accuracy for ARDS. To facilitate rapid bedside measurement of this biomarker, a point-of-care (POC) breath test was developed. A prototype already showed good reproducibility and repeatability for the detection of octane. In this study we aim to measure octane in exhaled breath of invasively ventilated intensive care unit (ICU) patients and validate the diagnostic accuracy of the breath test for the early diagnosis of ARDS. METHODS: This is a multicentre observational cohort study in patients admitted to the ICU receiving invasive ventilation for at least 24 hours. At least 500 patients in two academic hospitals in The Netherlands will be included. ARDS patients will be compared to patients without ARDS. ARDS diagnosis will be based on the Berlin Definition. Two diagnostic assessments will be performed during the first 72 hours of invasive ventilation, including breath sampling, arterial blood gas analysis and lung ultrasound (LUS). In patients fulfilling the criteria for ARDS, three additional breath samples will be taken to assess resolution. The primary endpoint is the diagnostic accuracy for ARDS, defined by the area under the receiver operating characteristics curve (AUROCC) of octane concentration in exhaled breath. Secondary endpoints are the association between exhaled breath octane and ARDS adjusted for confounders, and the added diagnostic accuracy of the breath test on top of the Lung Injury Prediction Score (LIPS). DISCUSSION: This is the first study that validates a metabolic biomarker of ARDS in an adequate sample size. The major novelty is the use of a POC breath test that has been specifically developed for the purpose of diagnosing ARDS. Strengths are; assessment in the early phase, in patients at risk for ARDS, longitudinal sampling and an expert panel to reliably diagnose ARDS. This study will provide a decisive answer on the question if exhaled breath metabolomics can be used to diagnose ARDS. TRIAL REGISTRATION: The trial is registered at trialregister.nl (ID: NL8226) with the tag "DARTS".
ABSTRACT
BACKGROUND: There is a demand for a non-invasive bedside method to diagnose Acute Respiratory Distress Syndrome (ARDS). Octane was discovered and validated as the most important breath biomarker for diagnosis of ARDS using gas-chromatography and mass-spectrometry (GC-MS). However, GC-MS is unsuitable as a point-of-care (POC) test in the intensive care unit (ICU). Therefore, we determined if a newly developed POC breath test can reliably detect octane in exhaled breath of invasively ventilated ICU patients. METHODS: Two developmental steps were taken to design a POC breath test that relies on gas-chromatography using air as carrier gas with a photoionization detector. Calibration measurements were performed with a laboratory prototype in healthy subjects. Subsequently, invasively ventilated patients were included for validation and assessment of repeatability. After evolving to a POC breath test, this device was validated in a second group of invasively ventilated patients. Octane concentration was based on the area under the curve, which was extracted from the chromatogram and compared to known values from calibration measurements. RESULTS: Five healthy subjects and 53 invasively ventilated patients were included. Calibration showed a linear relation (R2 = 1.0) between the octane concentration and the quantified octane peak in the low parts per billion (ppb) range. For the POC breath test the repeatability was excellent (R2 = 0.98, ICC = 0.97 (95% CI 0.94-0.99)). CONCLUSION: This is the first study to show that a POC breath test can rapidly and reliably detect octane, with excellent repeatability, at clinically relevant levels of low ppb in exhaled breath of ventilated ICU patients. This opens possibilities for targeted exhaled breath analysis to be used as a bedside test and makes it a potential diagnostic tool for the early detection of ARDS.
