Objective We investigated how a commercially available smartwatch that measures peripheral blood oxygen saturation (SpO2) can detect hypoxemia compared to a medical-grade pulse oximeter. Methods We recruited 24 healthy participants. Each participant wore a smartwatch (Apple Watch Series 6) on the left wrist and a pulse oximeter sensor (Masimo Radical-7) on the left middle finger. The participants breathed via a breathing circuit with a three-way non-rebreathing valve in three phases. First, in the 2-minute initial stabilization phase, the participants inhaled the ambient air. Then in the 5-minute desaturation phase, the participants breathed the oxygen-reduced gas mixture (12% O2), which temporarily reduced their blood oxygen saturation. In the final stabilization phase, the participants inhaled the ambient air again until SpO2 returned to normal values. Measurements of SpO2 were taken from the smartwatch and the pulse oximeter simultaneously in 30-s intervals. Results There were 642 individual pairs of SpO2 measurements. The bias in SpO2 between the smartwatch and the oximeter was 0.0% for all the data points. The bias for SpO2 less than 90% was 1.2%. The differences in individual measurements between the smartwatch and oximeter within 6% SpO2 can be expected for SpO2 readings 90%–100% and up to 8% for SpO2 readings less than 90%. Conclusions Apple Watch Series 6 can reliably detect states of reduced blood oxygen saturation with SpO2 below 90% when compared to a medical-grade pulse oximeter. The technology used in this smartwatch is sufficiently advanced for the indicative measurement of SpO2 outside the clinic. Trial Registration ClinicalTrials.gov NCT04780724
The pressure reactivity index (PRx) is a parameter for the assessment of cerebrovascular autoregulation, but its calculation is affected by artifacts in the source biosignals—intracranial pressure (ICP) and arterial blood pressure. We sought to describe the most common short-duration artifacts and their effect on the PRx. A retrospective analysis of 935 h of multimodal monitoring data was conducted, and five types of artifacts, characterized by their shape, duration, and amplitude, were identified: rectangular, fast impulse, isoline drift, saw tooth, and constant ICP value. Subsequently, all types of artifacts were mathematically modeled and inserted into undisturbed segments of biosignals. Fast impulse, the most common artifact, did not alter the PRx index significantly when inserted into one or both signals. Artifacts present in one signal exceeded the threshold PRx in less than 5% of samples, except for isoline drift. Compared to that, the shortest rectangular artifact inserted into both signals changed PRx to a value above the set threshold in 55.4% of cases. Our analysis shows that the effect of individual artifacts on the PRx index is variable, depending on their occurrence in one or both signals, duration, and shape. This different effect suggests that potentially not all artifacts need to be removed.
High-frequency oscillatory ventilation (HFOV), which uses a small tidal volume and a high respiratory rate, is considered a type of protective lung ventilation that can be beneficial for certain patients. A disadvantage of HFOV is its limited monitoring of lung mechanics, which complicates its settings and optimal adjustment. Recent studies have shown that respiratory system reactance (Xrs) could be a promising parameter in the evaluation of respiratory system mechanics in HFOV. The aim of this study was to verify in vitro that a change in respiratory system mechanics during HFOV can be monitored by evaluating Xrs. We built an experimental system consisting of a 3100B high-frequency oscillatory ventilator, a physical model of the respiratory system with constant compliance, and a system for pressure and flow measurements. During the experiment, models of different constant compliance were connected to HFOV, and Xrs was derived from the impedance of the physical model that was calculated from the spectral density of airway opening pressure and spectral cross-power density of gas flow and airway opening pressure. The calculated Xrs changed with the change of compliance of the physical model of the respiratory system. This method enabled monitoring of the trend in the respiratory system compliance during HFOV, and has the potential to optimize the mean pressure setting in HFOV in clinical practice.
Amyotrophic lateral sclerosis is a disease with rapid progression. The use of mechanical ventilation helps to manage symptoms and delays death. Use in a home environment could reduce costs and increase quality of life. The aim of this study is a cost–utility analysis of home mechanical ventilation in adult patients with amyotrophic lateral sclerosis from the perspective of healthcare payers in the Czech Republic. The study evaluates home mechanical ventilation (HMV) and mechanical ventilation (MV) in a healthcare facility. A Markov model was compiled for evaluation in a timeframe of 10 years. Model parameters were obtained from the literature and opinions of experts from companies dealing with home care and home mechanical ventilation. The cost–utility analysis was carried out at the end of the study and results are presented in incremental cost–utility ratio (ICUR) using quality-adjusted life-years. Uncertainty was assessed by one-way sensitivity analysis and scenario analysis. The cumulative costs of HMV are CZK 1,877,076 and the cumulative costs of the MV are CZK 7,386,629. The cumulative utilities of HMV are 12.57 quality-adjusted life year (QALY) and the cumulative utilities of MV are 11.32 QALY. The ICUR value is CZK-4,403,259. The results of this study suggest that HMV is cost effective.
The study deals with experimental measuring of attenuation of dynamic pressure during high-frequency oscillatory ventilation. The experimental circuit consists of high-frequency oscillatory ventilator Sensormedics 3100 B, patient circuit and lung model 5600i. Different values of the flow resistance and alveolar compliance were modelled during the experimental measurement. The ventilatory parameters of the oscillatory ventilator were constant during whole measurement. We confirm a decrease of the amplitude of the pressure swings in the alveolar space during high-frequency oscillatory ventilation. Dependence on the mechanical properties of the respiratory system was found. IntroductionArtificial lung ventilation (ALV) is used in many patients when spontaneous breathing is insufficient or intentionally inhibited. ALV is the most efficient method for treatment of acute respiratory failure. However, there are still strong adverse effects of ALV upon patient's respiratory system [1]. The adverse effects caused by ALV are known as ventilator induced lung injury. Current trend is to minimize the adverse effects of ALV in the respiratory care and new ventilatory regimens are introduced in order to ensure protective ventilation. One of these new techniques is high-frequency oscillatory ventilation (HFOV). Frequency of HFOV is higher compared with conventional artificial lung ventilation (CV) and the frequency rate is in range 3-25 Hz. Higher ventilatory frequency allows use of significantly smaller tidal volumes, which are comparable to anatomical dead space or even smaller. Also the pressure swings (ΔP) are decreased in the distal parts of the ventilatory circuit during HFOV in comparison with CV. The pressure swings are superimposed on the mean airway pressure (MAP) that inflates the lung. Use of MAP and smaller pressure swings during HFOV prevent the lungs from overdistension, barotrauma and volutrauma [2]. The difference in the frequency, pressure and tidal volume represent the most significant difference between HFOV and CV. It was shown in animal experiments that amplitude of the pressure swings is damped during HFOV. The alveolar pressure was measured by a capsule that was placed into the lung. The amplitude of the pressure swings was rapidly decreasing in the airways and only about 10 % of the input pressure was present in the alveolar space. The results were affected by the weight of the capsule and the placement of the capsule in the alveolar space [3,4]. It was showed that MAP is stable with different ventilator parameters and remains on the same level in all parts of the respiratory system [5]. The attenuation of the pressure swings was also studied by the mathematical model [6]. The simulations conducted on the model confirm the significant decrease of the amplitude of the pressure swings during HFOV. Less than 10 % of the input pressure amplitude is present in the alveolar space. The result of simulation conducted on the mathematical model can be seen in Image 1. Ratio of amplitude of the pressure swings for ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.