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Introduction: The stability of a new hyperbaric ventilator (Shangrila590, Beijing Aeonmed Company, Beijing, China) at different clinically relevant pressures in a hyperbaric chamber during pressure-controlled ventilation (PCV) was investigated. Methods: The ventilator was connected to a test lung in the multiplace hyperbaric chamber. The inspiratory pressure (PI) of the ventilator was set to 1.0, 1.5, 2.0, 2.5 and 3.0 kPa (approximately 10, 15, 20, 25 and 30 cmH2O). The compliance and resistance of the test lung were set to 200 mL·kPa⻹ and 2 kPa·L⻹·s⻹, respectively. Experiments were conducted at 101, 203 and 284 kPa ambient pressure (1.0, 2.0 and 2.8 atmospheres absolute respectively). At each of the 5 PI values, the tidal volume (VT), peak inspiratory pressure (Ppeak) and peak inspiratory flow (Fpeak) displayed by the ventilator and the test lung were recorded for 20 cycles. Test lung data were considered the actual ventilation values. The ventilation data were compared among the three groups to evaluate the stability of the ventilator. Results: At every PI, the Ppeak detected by the ventilator decreased slightly with increasing ambient pressure. The Fpeak values measured by the test lung decreased substantially as the ambient pressure increased. Nevertheless, the reduction in VT at 284 kPa and PI 30 cmH2O (compared to performance at 101 kPa) was comparatively small (approximately 60 ml). Conclusions: In PCV mode this ventilator provided relatively stable VT across clinically relevant PI values to ambient pressures as high as 284 kPa. However, because Fpeak decreases at higher ambient pressure, some user adjustment might be necessary for precise VT maintenance during clinical use at higher PIs and ambient pressures.
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Oxigenoterapia Hiperbárica , Volumen de Ventilación Pulmonar , Ventiladores Mecánicos , Oxigenoterapia Hiperbárica/métodos , Volumen de Ventilación Pulmonar/fisiología , Rendimiento Pulmonar/fisiología , Diseño de Equipo , Humanos , Cámaras de Exposición Atmosférica , Presión , Presiones Respiratorias Máximas , Presión Atmosférica , Respiración con Presión Positiva/métodos , Respiración con Presión Positiva/instrumentación , Respiración Artificial/instrumentación , Respiración Artificial/métodosRESUMEN
Long COVID symptoms typically occur within 3 months of an initial COVID-19 infection, last for more than 2 months, and cannot be explained by other diagnoses. The most common symptoms include fatigue, dyspnea, coughing, and cognitive impairment. The mechanisms of long COVID are not fully understood, but several hypotheses have been put forth. These include coagulation and fibrosis pathway activation, inflammatory and autoimmune manifestations, persistent virus presence, and Epstein-Barr virus reactivation. Hyperbaric oxygen therapy (HBOT) is a therapeutic method in which a person inhales 100% oxygen under pressure greater than that of the atmosphere. HBOT has some therapeutic effects, including improvement of microcirculation, inhibition of cytokine release leading to a reduction in inflammatory responses, inhibition of autoimmune responses, and promotion of neurological repair. Several clinical trials have been carried out using HBOT to treat long COVID. The results suggest that HBOT helps to improve symptom severity, reduce symptom duration, and enhance patients' quality of life. It is believed that HBOT is an effective option for patients with long COVID, which is worth actively promoting.
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COVID-19 , Infecciones por Virus de Epstein-Barr , Oxigenoterapia Hiperbárica , Humanos , Oxigenoterapia Hiperbárica/métodos , Oxígeno , Síndrome Post Agudo de COVID-19 , Calidad de Vida , COVID-19/terapia , Herpesvirus Humano 4RESUMEN
INTRODUCTION: The performance of the Shangrila590 hyperbaric ventilator (Beijing Aeonmed Company, Beijing, China) was evaluated during volume-controlled ventilation. METHODS: Experiments were conducted in a multiplace hyperbaric chamber at 101, 152, 203, and 284 kPa (1.0, 1.5, 2.0 and 2.8 atmospheres absolute [atm abs]). With the ventilator in volume control ventilation (VCV) mode and connected to a test lung, comparison was made of the set tidal volume (VTset) versus delivered tidal volume (VT) and minute volume (MV) at VTset between 400 and 1,000 mL. Peak inspiratory pressure was also recorded. All measurements were made across 20 respiratory cycles. RESULTS: Across all ambient pressures and ventilator settings the difference between VTset and actual VT and between predicted MV and actual MV were small and clinicially insignificant despite reaching statistical significance. Predictably, Ppeak increased at higher ambient pressures. With VTset 1,000 mL at 2.8 atm abs the ventilator produced significantly greater VT, MV and Ppeak. CONCLUSIONS: This new ventilator designed for use in hyperbaric environments performs well. It provides relatively stable VT and MV during VCV with VTset from 400 mL to 800 mL at ambient pressures from 1.0 to 2.8 atm abs, as well as VTset 1,000 mL at ambient pressures from 1.0 to 2.0 atm abs.
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Oxigenoterapia Hiperbárica , Humanos , Ventiladores Mecánicos , Volumen de Ventilación Pulmonar , Pulmón , Oxígeno , Respiración ArtificialRESUMEN
Hyperbaric oxygen (HBO) therapy is an effective treatment for patients with disorders of consciousness (DOC). In this study, real-time electroencephalogram (EEG) recordings were obtained from patients with DOC during HBO therapy. EEG microstate indicators including mean microstate duration (MMD), ratio of total time covered (RTT), global explained variance (GEV), transition probability, mean occurrence, and mean global field power (GFP) were compared before and during HBO therapy. The results showed that the duration of microstate C in all patients with DOC increased after 20 min of HBO therapy (p < 0.05). Further statistical analysis found that the duration of microstate C was longer in the higher CRS-R group (≥8, 17 cases) than in the lower group (<8, 24 cases) during HBO treatment. In the higher CRS-R group, the transition probabilities from microstate A to microstate C and from microstate C to microstate A also increased significantly compared with the probability before treatment (p < 0.05). Microstate C is generally considered to be related to a salience network; an increase in the transition probability between microstate A and microstate C indicates increased information exchange between the auditory network and the salience network. The results of this study show that HBO therapy has a specific activating effect on attention and cognitive control in patients and causes increased activity in the primary sensory cortex (temporal lobe and occipital lobe). This study demonstrates that real-time EEG detection and analysis during HBO is a clinically feasible method for assessing brain function in patients with DOC. During HBO therapy, some EEG microstate indicators show significant changes related to the state of consciousness in patients with chronic DOC. This will be complementary to important electrophysiological indicators for assessing consciousness and may also provide an objective foundation for the precise treatment of patients with DOC.
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Hyperbaric oxygen (HBO) therapy through breathing oxygen at the pressure of above 1 atmosphere absolute (ATA) is useful for varieties of clinical conditions, especially hypoxic-ischemic diseases. Because of generation of reactive oxygen species (ROS), breathing oxygen gas at high pressures can cause oxygen toxicity in the central nervous system, leading to multiple neurological dysfunction, which limits the use of HBO therapy. Studies have shown that Hydrogen gas (H2) can diminish oxidative stress and effectively reduce active ROS associated with diseases. However, the effect of H2 on ROS generated from HBO therapy remains unclear. In this study, we investigated the effect of H2 on ROS during HBO therapy using PC12 cells. PC12 cells cultured in medium were exposed to oxygen gas or mixed oxygen gas and H2 at 1 ATA or 5 ATA. Cells viability and oxidation products and ROS were determined. The data showed that H2 promoted the cell viability and inhibited the damage in the cell and mitochondria membrane, reduced the levels of lipid peroxidation and DNA oxidation, and selectively decreased the levels of â¢OH but not disturbing the levels of O2â¢-, H2O2, or NO⢠in PC12 cells during HBO therapy. These results indicated that H2 effectively reduced â¢OH, protected cells against oxygen toxicity resulting from HBO therapy, and had no effect on other ROS. Our data supported that H2 could be potentially used as an antioxidant during HBO therapy.
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Hidrógeno/farmacología , Radical Hidroxilo/metabolismo , Oxígeno/toxicidad , Animales , Supervivencia Celular/efectos de los fármacos , L-Lactato Deshidrogenasa/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Células PC12 , Ratas , Especies Reactivas de Oxígeno/metabolismoRESUMEN
OBJECTIVE: To evaluate the therapeutic effect and the oxidative stress effect of 9 and 18 hour hyperbaric oxygenation therapy (HBOT) protocols on the earliest stage of acute permanent middle cerebral artery occlusion (MCAO) in rats. METHODS: The permanent MCAO model of rats was used. The animals were randomly divided into 9 and 18 hour HBOT groups, as well as a control group. MAIN OUTCOME MEASURES: (1) The Garcia neurological grading system was used to assess the therapeutic effect of hyperbaric oxygenation therapy; (2) the infarct volume was calculated with the 2,3,5-triphenyltetrazolium chloride (TTC) pathologic staining and NIH Image J software 24 and 120 hours after MCAO; (3) the level of reactive oxygen species determined by superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) in ischemic brain tissue were separately examined at the 18, 48 and 120 hour post-ischemia time points using spectrophotometry. RESULTS: (1) There were significant improvements in the neurobehavioral outcome of the rats in the 9 and the 18 hour groups, as compared with rats from the control group (p<0.01); (2) cerebral infarct volume decreased 63-64% in the rats of 9 hour group and 51-66% in the 18 hour group at the 24 and 120 hour time points, as compared with that of the control group; (3) the SOD levels of the 9 and 18 hour groups were remarkably lower than those of control group after both 18 and 48 hours (p<0.01 and p<0.05); (4) the MDA level of the 9 and 18 hour groups were both remarkably lower than the control groups, especially at 18 hours (p<0.05). Meanwhile, the MDA level in the 9 hour group was remarkably lower than both the 18 hour group and the control group (p<0.01 and p<0.05); (5) the level of NO in both hyperbaric oxygenation therapy groups were remarkably higher than that of the control at 18 and 48 hour time points (p<0.01). While the level in 18 hour group was remarkably lower than that of 9 hour group at 18 hour time point (p<0.05). At the 120 hour mark, the NO levels were basically the same in all the three groups. CONCLUSIONS: (1) The two protocols of large dose hyperbaric oxygenation therapy are highly efficient in reducing infarct volume and improving neurobehavioral outcome in permanent MCAO rats within the earliest stages of stroke; (2) increased duration of hyperbaric oxygenation therapy does not appear to equate to improved outcomes; in fact, the longer duration may aggravate the oxidative stress in ischemic tissue.