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BACKGROUND: In recent years, advancements in cancer treatment have enabled cancer cell inhibition, leading to improved patient outcomes. However, the side effects of chemotherapy, especially leukopenia, impact patients' ability to tolerate their treatments and affect their quality of life. Traditional Chinese medicine is thought to provide complementary cancer treatment to improve the quality of life and prolong survival time among patients with cancer. OBJECTIVE: This study aims to evaluate the effectiveness of Chinese herbal medicine (CHM) as a complementary treatment for neutropenia prevention and immunity modulation during chemotherapy in patients with breast cancer. METHODS: We will conduct a real-world pragmatic clinical trial to evaluate the effectiveness of CHM as a supplementary therapy to prevent neutropenia in patients with breast cancer undergoing chemotherapy. Patients will be classified into CHM or non-CHM groups based on whether they received CHM during chemotherapy. Using generalized estimating equations or repeated measures ANOVA, we will assess differences in white blood cell counts, absolute neutrophil counts, immune cells, and programmed cell death protein 1 (PD-1) expression levels between the 2 groups. RESULTS: This study was approved by the research ethics committee of Hualien Tzu Chi Hospital (IRB 110-168-A). The enrollment process began in September 2021 and will stop in December 2024. A total of 140 patients will be recruited. Data cleaning and analysis are expected to finish in the middle of 2025. CONCLUSIONS: Traditional Chinese medicine is the most commonly used complementary medicine, and it has been reported to significantly alleviate chemotherapy-related side effects. This study's findings may contribute to developing effective interventions targeting chemotherapy-related neutropenia among patients with breast cancer in clinical practice. TRIAL REGISTRATION: International Traditional Medicine Clinical Trial Registry ITMCTR2023000054; https://tinyurl.com/yc353hes. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/55662.
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BACKGROUND: Tidal volume (Vt) delivery during mechanical ventilation is influenced by gas compression, humidity, and temperature. OBJECTIVES: This bench study aimed at assessing the accuracy of Vt delivery by paediatric intensive care ventilators according to the humidification system. Secondary objectives were to assess the following: (i) the accuracy of Vt delivery in ventilators with an integrated Y-piece pneumotachograph and (ii) the ability of ventilators to deliver and maintain a preset positive end-expiratory pressure. METHODS: Six latest-generation intensive care ventilators equipped with a paediatric mode were tested on the ASL5000 test lung in four simulated paediatric bench models (full-term neonate, infant, preschool-age chile, and school-age child), under volume-controlled mode with a heated humidifier (HH) or a heat moisture exchanger, with various loading conditions. Three ventilators equipped with a Y-piece pneumotachograph were tested with or without the pneumotachograph in the neonatal and infant models. "Accurate Vt" delivery was defined as a volume error (percentage of the preset Vt under body temperature and pressure and saturated water vapour conditions) being ≤10 % of the absolute preset value. RESULTS: Vt accuracy varied significantly across ventilators but was acceptable in almost all the ventilators and all the models, except the neonatal model. The humidification system had an impact on Vt delivery in the majority of the tested conditions (p < 0.05). The use of an HH was associated with a better Vt accuracy in four ventilators (V500, V800, R860, and ServoU) and allowed to achieve an acceptable level of volume error in the neonatal model as compared to the use of heat moisture exchanger. The use of an integrated pneumotachograph was associated with lower volume error in only one ventilator (p < 0.01). All the tested ventilators were able to maintain adequate positive end-expiratory pressure levels. CONCLUSION: The humidification system affects Vt accuracy of paediatric intensive care ventilators, especially in the youngest patients for whom the HH should be preferred.
Subject(s)
Tidal Volume , Ventilators, Mechanical , Humans , Infant, Newborn , Infant , Equipment Design , Respiration, Artificial , Child , Intensive Care Units, Pediatric , Child, Preschool , HumidityABSTRACT
Global pandemic due to COVID-19 has increased the interest for ventilators´ use worldwide. New devices have been developed and older ones have undergone a renewed interest, but we lack robust evidence about performance of each ventilator to match appropriate device to a given patient and care environment. The aim of this bench study was to investigate the performance of six devices for noninvasive ventilation, and to compare them in terms of volume delivered, trigger response, pressurization capacity and synchronization in volume assisted controlled and pressure support ventilation. All ventilators were tested under thirty-six experimental conditions by using the lung model ASL5000® (IngMar Medical, Pittsburgh, PA). Two leak levels, two muscle inspiratory efforts and three mechanical patterns were combined for simulation. Trigger function was assessed by measurement of trigger-delay time. Pressurization capacity was evaluated as area under the pressure-time curve over the first 500 ms after inspiratory effort onset. Synchronization was evaluated by the asynchrony index and by incidence and type of asynchronies in each condition. All ventilators showed a good performance, even if pressurization capacity was worse than expected. Leak level did not affect their function. Differences were found during low muscle effort and obstructive pattern. In general, Philips Trilogy Evo/EV300 and Hamilton C3 showed the best results. NIV devices successfully compensate air leaks but still underperform with low muscle effort and obstructive lungs. Clinicians´ must have a clear understanding of the goals of NIV both for devices´ choice and set main parameters to achieve therapy success.
Subject(s)
Noninvasive Ventilation , Respiration, Artificial , Humans , Equipment Design , Respiration, Artificial/methods , Ventilators, Mechanical , Positive-Pressure RespirationABSTRACT
BACKGROUND: As volatile anaesthetic gases contribute to global warming, improving the efficiency of their delivery can reduce their environmental impact. This can be achieved by rebreathing from a circle system, but also by anaesthetic reflection with an open intensive care ventilator. We investigated whether the efficiency of such a reflection system could be increased by warming the reflector during inspiration and cooling it during expiration (thermocycling). METHODS: The Sedaconda-ACD-S (Sedana Medical, Danderyd, Sweden) was connected between an intensive care ventilator and a test lung. Liquid isoflurane was infused into the device at 0.5, 1.0, 2.0 and 5.0 mL/h; ventilator settings were 500 mL tidal volume, 12 bpm, 21% oxygen. Isoflurane concentrations were measured inside the test lung after equilibration. Thermocycling was achieved by heating the breathing gas in the inspiratory hose to 37 °C via a heated humidifier without water. Breathing gas expired from the test lung was cooled to 14 °C before reaching the ACD-S. In the test lung, body temperature pressure saturated conditions prevailed. Isoflurane concentrations and reflective efficiency were compared between thermocycling and control conditions. RESULTS: With thermocycling higher isoflurane concentrations in the test lung were measured for all infusion rates studied. Interpolation of data showed that for achieving 0.4 (0.6) Vol% isoflurane, the infusion rate can be reduced from 1.2 to 0.7 (2.0 to 1.2) mL/h or else to 56% (58%) of control. CONCLUSION: Thermocycling of the anaesthetic gas considerably increases the efficiency of the anaesthetic reflector and reduces anaesthetic consumption by almost half in a test lung model. Given that cooling can be miniaturized, this method carries a potential for further saving anaesthetics in clinical practice in the operating theatre as well as for inhaled sedation in the ICU.
Subject(s)
Anesthetics, Inhalation , Isoflurane , Humans , Anesthesia, Inhalation , Heating , LungABSTRACT
BACKGROUND: Noninvasive ventilation (NIV) is the reference standard treatment for most situations of chronic respiratory failure. NIV settings must be titrated to both preserve upper-airway patency and control hypoventilation. Automatic adjustment of pressure support (PS) and expiratory positive airway pressure (EPAP) may facilitate the initiation and follow-up of domiciliary NIV. However, whether the automatic-adjustment algorithms embedded into current devices accurately detect, respond to, and score common sleep-related respiratory events remains unclear. METHODS: A bench was set up to simulate central hypopnea (CH), central apnea (CA), obstructive hypopnea (OH), and obstructive apnea (OA). Four home ventilators were evaluated, with their dedicated modes for automatic PS and EPAP adjustment. RESULTS: All 4 devices increased PS during CH, CA, and OH. However, PS adjustment varied widely in magnitude, with tidal volumes within 100 ± 20% of the target being provided by only 3 devices for CH, one for CA, and one for OH. Two devices increased EPAP for OH and 3 for OA, including one that also increased EPAP for CA. Only 2 devices scored residual hypopnea after simulated CA, and only one scored a residual event after OH. One device scored no event. CONCLUSIONS: Current NIV devices differed markedly in their responses to, and reporting of, standardized sleep-related respiratory events. Further improvements in embedded NIV algorithms are needed to allow more widespread out-of-laboratory initiation and follow-up of NIV.
Subject(s)
Noninvasive Ventilation , Sleep Apnea Syndromes , Sleep Apnea, Central , Sleep Apnea, Obstructive , Humans , Sleep/physiology , Positive-Pressure Respiration , Sleep Apnea Syndromes/therapyABSTRACT
BACKGROUND: The impact of leaks has mainly been assessed in bench models using continuous leak patterns which did not reflect real-life leakage. We aimed to assess the impact of the pattern and intensity of unintentional leakage (UL) using several respiratory models. METHODS: An active artificial lung (ASL 5000) was connected to three bilevel-ventilators set in pressure mode; the experiments were carried out with three lung mechanics (COPD, OHS and NMD) with and without upper airway obstruction. Triggering delay, work of breathing, pressure rise time, inspiratory pressure, tidal volume, cycling delay and the asynchrony index were measured at 0, 6, 24 and 36 L/min of UL. We generated continuous and inspiratory UL. RESULTS: Compared to 0 L/min of UL, triggering delays were significantly higher with 36 L/min of UL (+27 ms) and pressure rise times were longer (+71 ms). Cycling delays increased from -4 [-250-169] ms to 150 [-173-207] ms at, respectively 0 L/min and 36 L/min of UL and work of breathing increased from 0.15 [0.12-0.29] J/L to 0.19 [0.16-0.36] J/L. Inspiratory leakage pattern significantly increased triggering delays (+35 ms) and cycling delays (+263 ms) but decreased delivered pressure (-0.94 cmH2O) compared to continuous leakage pattern. Simulated upper airway obstruction significantly increased triggering delay (+199 ms), cycling delays (+371 ms), and decreased tidal volume (-407 mL) and pressure rise times (-56 ms). CONCLUSIONS: The pattern of leakage impacted more the device performances than the magnitude of the leakage per se. Flow limitation negatively reduced all ventilator performances.
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Background: The severe acute respiratory syndrome-coronavirus 2 pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. Methods: Validation consisted of (a) testing tidal volume delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome by saline lavage. Results: Differences in tidal volume in the simulated models were marginally different (largest difference 33 ml [95% CI 31 to 36]; P < .001). Plateau pressure was not different (-0.3 cmH2O [95% CI -0.9 to 0.3]; P = .409), and positive end-expiratory pressure was marginally different (0.3 cmH2O [95% CI 0.2 to 0.3]; P < .001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias -0.29 [limits of agreement 0.82 to -1.42], and mean bias 0.56 [limits of agreement 1.94 to -0.81], at a plateau pressure of 15 and 30 cmH2O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after acute respiratory distress syndrome induction. Conclusions: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The ACUTE-19 can provide the basis for the development of a future affordable commercial ventilator.
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Antecedentes: La pandemia producida por el síndrome respiratorio agudo severo por coronavirus 2 puede agotar los recursos sanitarios, especialmente de respiradores, en situaciones de escasez de recursos sanitarios. Nuestro objetivo fue realizar una evaluación preclínica rápida de un prototipo de respirador de turbina para la ventilación invasiva denominado ACUTE-19. Métodos: La validación consistió en: a) evaluación de la administración de un volumen corriente en 11 modelos pulmonares simulados, con diversas resistencias y compliancias; b) comparación con un ventilador comercial (VIVO-50) adaptando las recomendaciones de la Agencia Reguladora de Medicamentos y Productos Sanitarios del Reino Unido para ventiladores de fabricación rápida, y c) realización de pruebas in vivo en una oveja antes y después de inducir el síndrome de distrés respiratorio agudo mediante lavado salino. Resultados: Las diferencias de volumen corriente en los modelos simulados fueron mínimamente diferentes (la mayor diferencia fue de 33ml [IC 95%: 31 a 36]; p<0,001). La presión de meseta no fue diferente (−0,3cmH2O [IC 95%: −0,9 a 0,3]; p=0,409), y la presión positiva al final de la espiración fue levemente diferente (0,3cmH2O [IC 95%: 0,2 a 0,3]; p<0,001) comparando el ACUTE-19 y el ventilador comercial. El análisis de Bland-Altman mostró una buena concordancia (sesgo medio −0,29 [límites de concordancia 0,82 a −1,42], y sesgo medio 0,56 [límites de concordancia 1,94 a −0,81], a una presión de meseta de 15 y 30cmH2O, respectivamente). El ACUTE-19 consiguió una oxigenación y ventilación óptimas antes y después de la inducción del síndrome de distrés respiratorio agudo en el modelo animal. Conclusiones: El ACUTE-19 se comportó con precisión en los modelos simulados y animales, con un rendimiento comparable al del dispositivo comercial VIVO-50. El ACUTE-19 puede servir de base para el desarrollo de un futuro ventilador comercial asequible.(AU)
Background: The severe acute respiratory syndrome-coronavirus 2 pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. Methods: Validation consisted of (a) testing tidal volume delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome by saline lavage. Results: Differences in tidal volume in the simulated models were marginally different (largest difference 33ml [95% CI 31 to 36]; P<.001). Plateau pressure was not different (−0.3cmH2O [95% CI −0.9 to 0.3]; P=.409), and positive end-expiratory pressure was marginally different (0.3cmH2O [95% CI 0.2 to 0.3]; P<.001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias −0.29 [limits of agreement 0.82 to −1.42], and mean bias 0.56 [limits of agreement 1.94 to −0.81], at a plateau pressure of 15 and 30cmH2O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after acute respiratory distress syndrome induction. Conclusions: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The ACUTE-19 can provide the basis for the development of a future affordable commercial ventilator.(AU)
Subject(s)
Humans , Ventilators, Mechanical , Severe acute respiratory syndrome-related coronavirus , Pandemics , Coronavirus Infections/epidemiology , Respiratory Mechanics , Spain , Cardiopulmonary Resuscitation , AnesthesiologyABSTRACT
BACKGROUND: The Severe Acute Respiratory Syndrome (SARS)-Coronavirus 2 (CoV-2) pandemic pressure on healthcare systems can exhaust ventilator resources, especially where resources are restricted. Our objective was a rapid preclinical evaluation of a newly developed turbine-based ventilator, named the ACUTE-19, for invasive ventilation. METHODS: Validation consisted of (a) testing tidal volume (VT) delivery in 11 simulated models, with various resistances and compliances; (b) comparison with a commercial ventilator (VIVO-50) adapting the United Kingdom Medicines and Healthcare products Regulatory Agency-recommendations for rapidly manufactured ventilators; and (c) in vivo testing in a sheep before and after inducing acute respiratory distress syndrome (ARDS) by saline lavage. RESULTS: Differences in VT in the simulated models were marginally different (largest difference 33ml [95%-confidence interval (CI) 31-36]; P<.001ml). Plateau pressure (Pplat) was not different (-0.3cmH2O [95%-CI -0.9 to 0.3]; P=.409), and positive end-expiratory pressure (PEEP) was marginally different (0.3 cmH2O [95%-CI 0.2 to 0.3]; P<.001) between the ACUTE-19 and the commercial ventilator. Bland-Altman analyses showed good agreement (mean bias, -0.29, [limits of agreement, 0.82 to -1.42], and mean bias 0.56 [limits of agreement, 1.94 to -0.81], at a Pplat of 15 and 30cmH2O, respectively). The ACUTE-19 achieved optimal oxygenation and ventilation before and after ARDS induction. CONCLUSIONS: The ACUTE-19 performed accurately in simulated and animal models yielding a comparable performance with a VIVO-50 commercial device. The acute 19 can provide the basis for the development of a future affordable commercial ventilator.
Subject(s)
COVID-19 , Noninvasive Ventilation , Respiratory Distress Syndrome , Sheep , Animals , COVID-19/therapy , Ventilators, Mechanical , Tidal Volume , Respiratory Distress Syndrome/therapy , SARS-CoV-2ABSTRACT
BACKGROUND: Intrinsic PEEP during mechanical ventilation occurs when there is insufficient time for expiration to functional residual capacity before the next inspiration, resulting in air trapping. Increased expiratory resistance (RE), too rapid of a patient or ventilator breathing rate, or a longer inspiratory to expiratory time ratio (TI/TE) can all be causes of intrinsic PEEP. Intrinsic PEEP can result in increased work of breathing and patient-ventilator asynchrony (PVA) during patient-triggered breaths. We hypothesized that the difference between intrinsic PEEP and ventilator PEEP acts as an inspiratory load resulting in trigger asynchrony that needs to be overcome by increased respiratory muscle pressure (Pmus). METHODS: Using a Servo lung model (ASL 5000) and LTV 1200 ventilator in pressure control mode, we developed a passive model demonstrating how elevated RE increases intrinsic PEEP above ventilator PEEP. We also developed an active model investigating the effects of RE and intrinsic PEEP on trigger asynchrony (expressed as percentage of patient-initiated breaths that failed to trigger). We then studied if trigger asynchrony could be reduced by increased Pmus. RESULTS: Intrinsic PEEP increased significantly with increasing RE (r = 0.97, P = .006). Multivariate logistic regression analysis showed that both RE and negative Pmus levels affect trigger asynchrony (P < .001). CONCLUSIONS: A passive lung model describes the development of increasing intrinsic PEEP with increasing RE at a given ventilator breathing rate. An active lung model shows how this can lead to trigger asynchrony since the Pmus needed to trigger a breath is greater with increased RE, as the inspiratory muscles must overcome intrinsic PEEP. This model will lend itself to the study of intrinsic PEEP engendered by a higher ventilator breathing rate, as well as higher TI/TE, and will be useful in ventilator simulation scenarios of PVA. The model also suggests that increasing ventilator PEEP to match intrinsic PEEP can improve trigger asynchrony through a reduction in RE.
Subject(s)
Positive-Pressure Respiration, Intrinsic , Respiration, Artificial , Child , Humans , Exhalation , Lung , Respiration, Artificial/methods , Ventilators, MechanicalABSTRACT
INTRODUCTION: The aim of this laboratory study is to objectively analyze the new hydrophobic, acrylic, enhanced monofocal intraocular lens Acunex Quantum (AN6Q) and compare it with the monofocal platform Acunex AN6. METHODS: Two IOL models were analyzed (Acunex Quantum AN6Q and Acunex AN6, Teleon Surgical, Spankeren, Netherlands), each having the same refractive power of + 22.0 D, on the optical bench with the OptiSpheric IOL PRO 2. The measurements followed the guidelines of the International Standard Organization with following parameters: ISO 2 cornea (+ 0,28 µ), ISO 11979/2, lens placement in situ in NaCl with 35° temperature, 546 nm and selection of different aperture sizes (3.0 mm vs 4.5 mm). The aberrations of each IOL were evaluated by the WaveMaster IOL 2, a high-resolution Shack-Hartmann sensor in reverse projection setup. An in-situ model eye was used according to ISO 11979 in NaCl (n = 1.337) with 546 nm, mask width 4.51. Zernike polynomials up to 10th order were determined by means of the measured wavefront that describe the optical properties of the IOL. RESULTS: Through frequency modulation transfer function (mean) at 50 lp/mm (AN6Q/AN6 centered) was 0.687/0.731 (3.0 mm aperture) and 0.400/0.509 (4.5 mm aperture). The SR (mean) was 0.592/0.809 (3.0 mm) and 0.332/0.372 (4.5 mm). The MTF (mean) at 50 lp/mm (AN6Q/AN6 decentered by 1 mm) was 0.413/0.478 (3.0 mm) and 0.257/0.229 (4.5 mm). The SR (mean) was 0.393/0.404 (3.0 mm) and 0.183/0.212 (4.5 mm). The MTF (mean) at 50 lp/mm (AN6Q/AN6 tilted by 5°) was 0.508/0.710 (3.0 mm) and 0.337/0.513 (4.5 mm). The SR (mean) was 0.508/0.760 (3.0 mm) and 0.235/0.2372 (4.5 mm). AN6Q showed MTF peak of 0.55 with an enlarged depth of power of about 2.5 D and two cusps in the MTF curve. The spherical aberration Z 4-0 was about -0.21 µm and the secondary spherical aberration Z 6-0 was about 0.16 µm. No other relevant aberration showed up. CONCLUSION: The new, enhanced monofocal AN6Q provides an extended range of focus with only slight decrease in contrast quality. Both types of the hydrophobic, acrylic Acunex IOL platform have its particular advantages in clinical settings and therefore its importance, respectively.
Subject(s)
Lenses, Intraocular , Sodium Chloride , Eye, Artificial , Humans , Prosthesis Design , Vision, OcularABSTRACT
OBJECTIVES: This study sought to determine the degree of Evolut (Medtronic) leaflet pinning, diameter expansion, leaflet overhang, and performance at different implant depths of the balloon-expandable Sapien 3 (S3, Edwards Lifesciences LLC) transcatheter heart valve (THV) within the Evolut THV. BACKGROUND: Preservation of coronary access and flow is a major factor when considering the treatment of failed Evolut THVs. METHODS: An in vitro study was performed with 20-, 23-, 26-, and 29-mm S3 THVs deployed within 23-, 26-, 29-, and 34-mm Evolut R THVs, respectively. The S3 outflow was positioned at various depths at node 4, 5, and 6 of the Evolut R. Neoskirt height, leaflet overhang, performance, and Evolut R valve housing diameter expansion were assessed under physiological conditions as per ISO 5840-3 standard. RESULTS: The neoskirt height for the Evolut R was shorter when the S3 outflow was positioned at node 4 compared with node 6 (node 4 height for 23 mm = 16.3 mm, 26 mm = 17.1 mm, 29 mm = 18.3 mm, and 34 mm = 19.9 mm vs node 6 height for 23 mm = 23.9 mm, 26 mm = 23.4 mm, 29 mm = 24.7 mm, and 34 mm = 27 mm Evolut R). All configurations exhibited acceptable hydrodynamic performance irrespective of the degree of leaflet overhang, except the 29-mm S3 implanted in 34-mm Evolut R at node 4 (regurgitant fraction >20%). The valve housing radius of the index Evolut R increased when the S3 was implanted, with the increase ranging from 0 to 2.5 mm. CONCLUSIONS: Placement of the S3 at a lower implant position within an index Evolut R reduces the neoskirt height with no significant compromise to S3 valve function despite a higher degree of leaflet overhang. Low S3 implantation may facilitate future coronary access after redo transcatheter aortic valve replacement.
Subject(s)
Aortic Valve Stenosis , Heart Valve Prosthesis , Transcatheter Aortic Valve Replacement , Aortic Valve/diagnostic imaging , Aortic Valve/surgery , Aortic Valve Stenosis/surgery , Humans , Prosthesis Design , Transcatheter Aortic Valve Replacement/adverse effects , Treatment OutcomeABSTRACT
BACKGROUND: The RAM cannula (Neotech, Valencia, CA) has become a commonly used interface for CPAP in neonatal intensive care. Performance characteristics of this interface used with a critical care ventilator are not well described. METHODS: This was a bench study utilizing a lung simulator configured as an actively breathing infant (weights of 800 g, 1.5 kg, and 3 kg) with moderate lung disease and a critical care ventilator in CPAP mode with leak compensation on. Three sizes of the RAM cannulae (preemie, newborn, and infant) were compared to 3 BabyFlow nasal prongs (Dräger Medical, Lübeck, Germany) (medium, large, and extra-large). Fabricated nasal models produced a 70% occlusive fit for the RAM cannula and an occlusive fit with the Dräger prongs. Delivered flow and pressure levels were recorded at 9 CPAP levels between 5 and 20 cm H2O. RESULTS: The Dräger prongs produced a mean airway pressure ([Formula: see text]) within 0.20 cm H2O (range -0.10 to 0.35) of the set CPAP across all evaluated prong sizes and CPAP levels. In contrast, the RAM cannula produced [Formula: see text] values that averaged 8.5 cm H2O (range -15 to -3.5) below the set CPAP levels. The deficit in delivered versus target CPAP level for the RAM cannula increased with greater set CPAP. Set CPAP of 5 cm H2O delivered [Formula: see text] values that ranged from 0.6 to 1.5 cm H2O (difference of 3.5-4.4 cm H2O). Set CPAP of 20 cm H2O delivered [Formula: see text] values that ranged from 5.0 to 8.4 cm H2O (difference of 11.7-15 cm H2O). Inspiratory flow required to achieve set CPAP levels did not differ between interfaces, suggesting high resistance in the RAM cannula device masks the delivered CPAP levels. CONCLUSIONS: Use of the RAM cannula with a 30% leak on a critical care ventilator delivered [Formula: see text] values lower than set CPAP. This may be clinically meaningful and should be considered when choosing a nasal interface.
Subject(s)
Continuous Positive Airway Pressure , Ventilators, Mechanical , Cannula , Humans , Infant, Newborn , Intensive Care, Neonatal , NoseABSTRACT
OBJECTIVE: To address the issue of ventilator shortages, our group (eSpiro Network) developed a freely replicable, open-source hardware ventilator. DESIGN: We performed a bench study. SETTING: Dedicated research room as part of an ICU affiliated to a university hospital. SUBJECTS: We set the lung model with three conditions of resistance and linear compliance for mimicking different respiratory mechanics of representative intensive care unit (ICU) patients. INTERVENTIONS: The performance of the device was tested using the ASL5000 lung model. MEASUREMENTS AND MAIN RESULTS: Twenty-seven conditions were tested. All the measurements fell within the ±10% limits for the tidal volume (VT). The volume error was influenced by the mechanical condition (p = 5.9 × 10-15) and the PEEP level (P = 1.1 × 10-12) but the clinical significance of this finding is likely meaningless (maximum -34 mL in the error). The PEEP error was not influenced by the mechanical condition (p = 0.25). Our experimental results demonstrate that the eSpiro ventilator is reliable to deliver VT and PEEP accurately in various respiratory mechanics conditions. CONCLUSIONS: We report a low-cost, easy-to-build ventilator, which is reliable to deliver VT and PEEP in passive invasive mechanical ventilation.
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Background: Adequate sedation is important for the treatment of ICU patients. AnaConDa (Anesthetic-Conserving-Device; ACD; Sedana Medical, Sweden), connected between ventilator and the patient, retains isoflurane during expiration, and releases it back during inspiration. The reflection efficiency (RefEff) corresponds to the percentage of expired anesthetic molecules that are re-inspired. We compared RefEff of AnaConDa-S (ACD-50) and AnaConDa-100 (ACD-100) under laboratory (DRY) and simulated clinical conditions (CLIN) using a test lung.Methods: Measurements were made under DRY and CLIN, with different tidal volumes (TV: 300 mL & 500 mL) and infusion rates (0.5-10 mL·h-1). RefEff was calculated from the isoflurane concentration in the test-lung (CISO) and plotted against the anesthetic vapor volume exhaled in one breath (V-exh = CISO·TV).Results: DRY: RefEff of both devices was ≈90% over a wide range of V-exh, but decreased when V-exh exceeded 5-7 mL (ACD-50) or 10-15 mL (ACD-100).CLIN: RefEff of ACD-50 was 70-80% (ACD-100: 80-90%), decreasing gradually with increasing V-exh. For 1 Vol.% isoflurane at TV500, the infusion rate with ACD-50 was twofold higher compared to ACD-100 (4 versus 2 mL·h-1).Conclusion: Under DRY and concentrations <1.5 Vol.%, RefEff of both devices is around 90%. Under CLIN, ACD-100 performs better with RefEff between 80% and 90% (ACD-50:70-80%), decreasing with increased vapor volume exhaled in one breath.
Subject(s)
Isoflurane/administration & dosage , Laboratories , Lung/physiology , Anesthesia , Anesthetics, Inhalation/administration & dosage , Equipment Design , Humans , Tidal Volume , Ventilators, MechanicalABSTRACT
BACKGROUND: Adaptive servoventilation (ASV) is a recently developed ventilation mode designed to stabilize ventilation in patients with central sleep apnea and Cheyne-Stokes respiration. Alternatively, modes aiming to maintain average ventilation over several breaths, such as average volume-assured pressure support (AVAPS) and intelligent volume-assured pressure support (iVAPS), could be efficient during ventilation instability by reducing central events. These modes are available on a variety of devices. This bench evaluation studied the response of these different modes and devices to simulated transient hypoventilation events. METHODS: Three home ventilation devices operating in ASV modes (AirCurve S10 VAuto, ResMed; DreamStation autoSV, Philips; Prisma CR, Löwenstein) and 2 ventilators with the AVAPS mode (DreamStation BiPAP, Philips; Lumis iVAPS, ResMed) were evaluated during transient central hypopnea/hypoventilation simulations characterized by a constant breathing frequency of 15 breaths/min and a progressive decrease of tidal volume (VT) from 500 mL to 50 mL, in 18, 12, 9, and 6 breaths, respectively, followed by a progressive return to the baseline at the same rate. RESULTS: The AirCurve S10 VAuto reacted to a VT decrease between 80% and 50% of baseline VT. DreamStation BiPAP and Prisma CR reacted when VT decreased to between 60% and 30% of baseline VT, whereas the AVAPS response to hypopnea occurred during the crescendo phase of hypopnea/hypoventilation VT. The iVAPS response was between that of the AirCurve S10 VAuto and the other ASV devices. Among the ASV devices, the minimum VT was higher with AirCurve S10 VAuto, followed by the Prisma CR and the DreamStation BiPAP. Minimum VT was not influenced by AVAPS and was improved by iVAPS without outperforming the AirCurve S10 VAuto. Maximum VT was increased by iVAPS, whereas ASV devices did not induce a significant VT overshoot. CONCLUSIONS: ASV devices improved central hypopnea/hypoventilation events without inducing hyperpnea events and therefore were better adapted than AVAPS and iVAPS devices, with notable differences in their responses to hypoventilation events.
Subject(s)
Hypoventilation , Cheyne-Stokes Respiration , Continuous Positive Airway Pressure , Humans , Hypoventilation/therapy , Sleep Apnea, Central/therapy , Tidal VolumeABSTRACT
BACKGROUND: Double-triggering is a well-recognized form of patient-ventilator asynchrony in noninvasive ventilation (NIV). This benchtop simulated lung study aimed to determine under which patient and device-specific conditions double-triggering is more prevalent, and how this influences the delivery of NIV. METHODS: Two commonly used proprietary NIV devices were tested using a benchtop lung model. Lung compliance, airway resistance, respiratory effort, and breathing frequency were manipulated, and the frequency of double-triggering was assessed. A lung model of very low lung compliance (15 mL/cm H2O) was then used to assess the frequency of double-triggering when breathing frequency and respiratory effort were varied, along with basic NIV settings, including inspiratory pressure and expiratory pressure. Minute ventilation and total inspiratory work (as calculated by the simulated lung model) were also correlated with frequency of double-triggering. RESULTS: In both devices, double-triggering was observed with reduced lung compliance (P = .02 and P < .001 for the two devices, respectively). Reduced airway resistance was associated with double-triggering with the one device only (P = .02). Respiratory effort and breathing frequency were not independent predictors of double-triggering across all lung models. In the lung model of very low lung compliance, both devices showed increased double-triggering at a lower breathing frequency (P < .001 and P < .001), higher respiratory effort (P = .03 and P < .001), and greater pressure support (P = .044, P < .001). Importantly, double-triggering was associated with reduced minute ventilation (P = .007) with one device and increased inspiratory work (P < .001) with the other device. CONCLUSIONS: Both simulated-patient and device characteristics influenced the frequency of double-triggering in NIV, resulting in meaningful consequences in a simulated lung model.
Subject(s)
Noninvasive Ventilation , Humans , Lung , Positive-Pressure Respiration , Ventilators, Mechanical , Work of BreathingABSTRACT
OBJECTIVES: The carbon dioxide (CO2 ) diffusion coefficient (DCO 2 ) reflects CO 2 removal during high-frequency oscillatory ventilation (HFOV). We hypothesized that despite leak flow during noninvasive HFOV (nHFOV) DCO 2 continues to indicate ventilation efficacy. METHODS: A neonatal airway model including CO2 production and an adjustable oropharyngeal leak was connected to a ventilator via bi-nasal prongs. Pressures and gas flows were measured at prongs, trachea, and leak. Oscillatory tidal volumes below (V T trachea ) and above the leak (V T prong ) were calculated from tracheal and leak flows. DCO 2 was calculated using V T trachea (DCO 2 trachea ) and V T prong (DCO 2 prong ) and compared with CO 2 partial pressure (pCO 2 ). Effects of leak flow (0, 5, or 10 L/min) on DCO 2 were assessed at fixed pressure amplitudes or predefined oscillatory volumes under steady-state pCO 2 conditions in the modeled lung. RESULTS: DCO2 trachea correlated strongly with pCO 2 , independent of the leak flow level (P < 0.0001). DCO 2 prong correlated with pCO 2 without and with moderate leak (P < 0.0001) but not with maximum leak (P = 0.1432). V T trachea correlated with the quotient of tracheal pressure amplitude and frequency irrespective of the leak (P < 0.0001). Based on the pressure amplitude at prong level (A prong ) V T trachea continued to follow a linear model of which the slopes decreased with increasing leak flow. V T prong correlated with the quotient of A prong and frequency, irrespective of the leak (P < 0.0001). CONCLUSIONS: DCO2 obtained at the airway opening at prong level reflects ventilation efficacy during nHFOV even in the presence of moderate oropharyngeal leak.
Subject(s)
Carbon Dioxide/metabolism , High-Frequency Ventilation , Models, Biological , Humans , Infant, Newborn , Lung/physiology , Tidal Volume , Trachea/physiology , Ventilators, MechanicalABSTRACT
BACKGROUND: During recent years, ventilators using turbines as flow-generating systems have become increasingly more relevant. This bench study was designed to compare triggering and pressurization of 7 turbine mid-level ICU ventilators. METHODS: We used a dual-chamber lung model to test 7 mid-level ICU ventilators in pressure support mode with levels of 10, 15, and 20 cm H2O with 2 PEEP levels of 5 cm H2O and the minimum level allowed by the ventilator. A ventilator was connected to the master chamber to simulate 2 different effort levels. Pressure drop, trigger delay time, time to minimum pressure, and pressure time products (PTP) during trigger and the first 300 and 500 ms were analyzed. RESULTS: In the trigger evaluation, the Savina had the highest delay time, whereas the C2, the V60, and the Trilogy had the lowest pressure drops and PTP values in both effort levels. In pressurization capacity assessment using ideal PTP300 and PTP500 percentages, the C2 and the V680 had the best results, and the Carina and the Savina had lower values, with no differences between both effort levels. Differences between PEEP levels did not seem to be relevant. CONCLUSIONS: Pressure support mode for tested ventilators worked properly, but pressurization capacity and trigger function performance were clearly superior in the newest machines. The use of PEEP did not modify the results.
Subject(s)
Respiration, Artificial/instrumentation , Ventilators, Mechanical , Computer Simulation , Critical Care , Equipment Design , Humans , Lung/physiology , Models, Biological , Pressure , Respiration, Artificial/methodsABSTRACT
BACKGROUND AND AIMS: Even though numerous ventilators are licensed for a use in children, very few have been specifically developed for this age range. Therefore, home ventilators may not be able to adequately synchronize with the child's respiratory effort, and the inspiratory triggers (ITs) of assist modes are not always appropriate for children. The aim of the study was to test the improvement of the IT of a ventilator on a pediatric bench and in pediatric patients. METHODS: A classical IT (ITc) and an improved IT [non-invasive ventilation (NIV) + IT] were tested on a bench with six pediatric profiles and in six young patients (mean age 14.1 ± 2.7 years old) requiring long-term NIV. RESULTS: On the bench, trigger time delays (ΔT) and trigger pressures (ΔP) were reduced with the NIV + IT as compared with the ITc (ΔT: 0.481 ± 0.332 vs 0.079 ± 0.022 s for ITc and NIV + IT, respectively, P = 0.027; ΔP: -1.40 ± 0.70 vs -0.42 ± 0.28 cmH2 O for ITc and NIV + IT, respectively, P = 0.046). The clinical study confirmed the decrease in ΔT (0.267 ± 0.061 vs 0.178 ± 0.074 s for ITc and NIV + IT, respectively, P = 0.024) and ΔP (-0.68 ± 0.26 vs -0.39 ± 0.11 cmH2 O for ITc and NIV + IT, respectively, P = 0.030). CONCLUSIONS: The sensitivity of the IT of a ventilator can be improved for pediatric use. The improvements observed on the bench study were confirmed in pediatric patients.