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Conventional mechanical ventilation has adverse impacts on the hemodynamics of elderly, hypertensive ICU patients. Limited studies have addressed ways to ameliorate these negative effects. This study aimed to determine whether heliox ventilation could improve the hemodynamics, especially microcirculation, of elderly, hypertensive patients undergoing mechanical ventilation. Thirty-eight patients, over the age of 65 with essential hypertension who underwent invasive mechanical ventilation treatment, were divided into two groups: a control group of nitrogen‑oxygen ventilation (n = 19) and an experimental group of heliox ventilation (n = 19). The control group received conventional room air ventilation and the experimental group adopted the innovative, closed heliox ventilation technique. Changes in blood pressure, heart rate (HR), peripheral oxygen saturation (SpO2), central venous oxygen saturation (ScvO2), regional cerebral oxygen saturation (rSO2), lactic acid (Lac) and airway pressure were measured at 0,1,2,3 h under volume-controlled ventilation (VCV) mode throughout the study. Sublingual microcirculation parameters were additionally measured at 0 h and 3 h of ventilation treatment. SpO2 in both groups increased after 1 h of ventilation compared with 0 h (p < 0.001), subsequently remaining stable. Compared with the control group, the experimental group showed a decrease in airway pressure and Lac, while blood pressure, ScvO2, and rSO2 increased (p < 0.05). Moreover, the sublingual microcirculation indexes in the experimental group improved compared with the control group (p < 0.05). Heliox ventilation improves blood pressure and microcirculation in elderly hypertensive patients and may resolve the limitations of traditional nitrogen‑oxygen ventilation. This trial was registered. The Chinese trial registration number is ChiCTR2100043945. The date of registration is 6-3-2021. •Adopting the innovative, closed heliox ventilation technique.•Expanding the application of heliox ventilation and providing a novel modality for the mechanical ventilation of elderly patients.•A hermetic breathing circuit was innovatively applied for heliox ventilation to recycle helium.•Heliox has a protective effect on hemodynamics in elderly hypertensive, mechanically-ventilated patients.

Abstract Rationale Normoxic heliox (mixture of 79% He and 21% O2) may enhance exercise tolerance in patients with chronic obstructive pulmonary disease (COPD). It remains to be determined whether part of these beneficial effects could be ascribed to increased O2 delivery (O2DEL) to locomotor muscles. Objectives To investigate the effects of heliox on peripheral O2DEL and utilization during exercise in moderate to severe COPD. Methods Twelve mildly hypoxic or nonhypoxemic men (FEV1 = 45.0 ± 13.0% predicted) underwent constant-work rate tests (70–80% peak) to the limit of tolerance while receiving heliox or room air. Near-infrared spectroscopy determined changes (Δ) in leg muscle deoxygenation (deoxyhemoglobin concentration [HHb], an index of fractional O2 extraction), and surface electromyography estimated muscle fiber recruitment (n = 5). Q̇ and SpO2 were monitored by impedance cardiography and pulse oximetry, respectively. Measurements and Main Results Heliox significantly decreased dynamic hyperinflation and increased exercise tolerance compared with room air (640 ± 95 s vs. 371 ± 100 s; P < 0.01). Heliox also accelerated on-exercise dynamics of Q̇, which were accompanied by faster O2 uptake kinetics and slower Δ[HHb] responses (P < 0.05). During steady-state exercise, SpO2-corrected Δ[HHb] values decreased with heliox despite no significant changes in cardiac output. Muscle fiber recruitment and leg effort scores were also diminished (P < 0.05). On a multiple regression analysis, reductions in dynamic hyperinflation, dyspnea, and Δ[HHb] were independently related to improvements in exercise tolerance with heliox (R2 = 0.91; P < 0.01). Conclusions Heliox increases lower limb O2DEL and utilization during dynamic exercise in patients with moderate to severe COPD. These effects enhance exercise tolerance in this patient population.

Abstract Rationale Hyperoxia and normoxic helium independently reduce dynamic hyperinflation and improve the exercise tolerance of patients with chronic obstructive pulmonary disease (COPD). Combining these gases could have an additive effect on dynamic hyperinflation and a greater impact on respiratory mechanics and exercise tolerance. Objective To investigate whether helium-hyperoxia improves the exercise tolerance and respiratory mechanics of patients with COPD. Methods Ten males with COPD (FEV1 = 47 ± 17%pred [mean ± SD]) performed randomized constant-load cycling at 60% of maximal work rate breathing air, hyperoxia (40% O2, 60% N2), normoxic helium (21% O2, 79% He), or helium-hyperoxia (40% O2, 60% He). Measurements Exercise time, inspiratory capacity (IC), work of breathing, and exertional symptoms were measured with each gas. Results Compared with air (9.4 ± 5.2 min), exercise time was increased with hyperoxia (17.8 ± 5.8 min) and normoxic helium (16.7 ± 9.1 min) but the improvement with helium-hyperoxia (26.3 ± 10.6 min) was greater than both these gases (p = 0.019 and p = 0.007, respectively). At an isotime during exercise, all three gases reduced dyspnea and both helium mixtures increased IC and tidal volume. Only helium-hyperoxia significantly reduced the resistive work of breathing (15.8 ± 4.2 vs. 10.1 ± 4.1 L · cm H2O−1) and the work to overcome intrinsic positive end-expiratory pressure (7.7 ± 1.9 vs. 3.6 ± 2.1 L · cm H2O−1). At symptom limitation, tidal volume remained augmented with both helium mixtures, but IC and the work of breathing were unchanged compared with air. Conclusion Combining helium and hyperoxia delays dynamic hyperinflation and improves respiratory mechanics, which translates into added improvements in exercise tolerance for patients with COPD.

Purpose To evaluate the efficacy of delivering a mixture of helium and oxygen gas (He–O 2 ) in spontaneous ventilation. Three high oxygen flow reservoir masks were tested: the Heliox21, specifically designed for helium; the Hi-Ox 80 mask, with an inspiratory and an expiratory valve; and a standard high-concentration face mask. Methods This prospective randomized crossover study was performed in six healthy volunteers in a laboratory setting. Volunteers breathed a mixture of 78% He/22% O 2 through each of the masks under two different breathing conditions (rest and hyperventilation: minute ventilation of 14.9 ± 6.1 and 26.7 ± 8.7 L min −1 , respectively) and four different He–O 2 flow rates (7, 10, 12, and 15 L min −1 ). Results A nasopharyngeal catheter was used to estimate He pharyngeal concentration (Fp [He]) in the airways in order to determine the percentage of contamination with room air (% air cont) at end-expiration. Under all testing conditions, the Hi-Ox 80 mask presented a significantly lower % air cont. During resting breathing pattern, a Fp [He] higher than 50% was achieved in 54% of the tests performed with the Hi-Ox 80 mask compared to 29% for the Heliox21 mask and only 17% for the standard mask. At hyperventilation, a Fp [He] higher than 50% was achieved in 17% of the tests performed with the Hi-Ox mask compared to 4% for the other two masks. Conclusion He–O 2 administration via the usual high-concentration reservoir masks results in significant dilution by room air. The Hi-Ox 80 mask minimized room air contamination and much more frequently achieved a pharyngeal He concentration higher than 50%.

The aim of this study was to establish an effective and safe protocol for in vivo oral candidiasis treatment with atmospheric plasma jets. A novel amplitude-modulated cold atmospheric pressure plasma jet (AM-CAPPJ) device, operating with Helium, was tested. In vitro assays with Candida albicans biofilms and Vero cells were performed in order to determine the effective parameters with low cytotoxicity. After the determination of such parameters, the protocol was evaluated in experimentally induced oral candidiasis in mice. AM-CAPPJ could significantly reduce the viability of C. albicans biofilms after 5 minutes of plasma exposure when compared to the non-exposed group (p = 0.0033). After this period of exposure, high viability of Vero cells was maintained (86.33 ± 10.45%). Also, no late effects on these cells were observed after 24 and 48 hours (83.24±15.23% and 88.96±18.65%, respectively). Histological analyses revealed significantly lower occurrence of inflammatory alterations in the AM-CAPPJ group when compared to non-treated and nystatin-treated groups (p < 0.0001). Although no significant differences among the values of CFU/tongue were observed among the non-treated group and the groups treated with AM-CAPPJ or nystatin (p = 0.3201), histological analyses revealed marked reduction in candidal tissue invasion. In conclusion, these results point out to a clinical applicability of this protocol, due to the simultaneous anti-inflammatory and inhibitory effects of AM-CAPPJ with low cytotoxicity.

Aerosolised drugs are prescribed for use in a range of inhaler devices and systems. Delivering drugs by inhalation requires a formulation that can be successfully aerosolised and a delivery system that produces a useful aerosol of the drug; the particles or droplets need to be of sufficient size and mass to be carried to the distal lung or deposited on proximal airways to give rise to a therapeutic effect. Patients and caregivers must use and maintain these aerosol drug delivery devices correctly. In recent years, several technical innovations have led to aerosol drug delivery devices with efficient drug delivery and with novel features that take into account factors such as dose tracking, portability, materials of manufacture, breath actuation, the interface with the patient, combination therapies, and systemic delivery. These changes have improved performance in all four categories of devices: metered dose inhalers, spacers and holding chambers, dry powder inhalers, and nebulisers. Additionally, several therapies usually given by injection are now prescribed as aerosols for use in a range of drug delivery devices. In this Review, we discuss recent developments in the design and clinical use of aerosol devices over the past 10–15 years with an emphasis on the treatment of respiratory disorders.

Objectives To measure the extent of dilution of helium-oxygen (heliox) by room air when given via high concentration reservoir mask to spontaneously breathing subjects. Substantial dilution of heliox by room air under these circumstances might alter its physical properties sufficiently to negate any potential clinical benefit in obstructive respiratory failure. Design Healthy volunteers breathing different concentrations of helium in oxygen via two different masks in a randomised crossover design. Setting Operating theatre in a university hospital. Patients and participants Six healthy volunteers. Interventions The concentrations of helium, nitrogen and oxygen were measured in the trachea of each volunteer using a mass spectrometer during normal breathing, hyperventilation and hypoventilation. Measurements and results During normal breathing of Heliox21 (79% helium) via a standard non-rebreathe reservoir mask, within subject median percentage tracheal helium was 37.2% (range 29.3–52.2%) and nitrogen was 41.7% (27.4–49.4%). Air entrainment was affected by changes in breathing pattern: tracheal nitrogen concentration was greater during hyperventilation (55.4%; range 49.4–63.5%) and less during hypoventilation (33.1%; range 24.6–39.6%, p  = 0.043). Tracheal nitrogen could be almost completely abolished by administering heliox via a tightly fitting cushioned facemask, even during hyperventilation (2.2%; range 0.6–6.1%, p  = 0.028). Conclusions Heliox administration via a standard high-concentration reservoir mask leads to significant dilution by room air. For the full potential benefits of heliox to be realised in spontaneously breathing patients, it should be administered via a system that achieves a gas tight seal, with no leaks between the delivery device and the surroundings.

High-frequency oscillatory ventilation (HFOV) at frequencies of approximately 15 Hz is associated with optimal CO 2 excretion. Higher frequencies using a nitrogen–oxygen gas mixture worsen CO 2 excretion. An in vitro experiment using HFOV and a helium–oxygen gas mixture showed a significant increase in CO 2 transport, which increased with increases in ventilation frequency. We hypothesised that in HFOV, the change in the arterial partial pressure of CO 2 (PaCO 2 ) would be greater at frequencies above 15 Hz when combined with helium–oxygen gas mixture administration. We tested this hypothesis in a hypoventilated healthy rabbit model by administering a helium–oxygen gas mixture at 15, 25, 35, and 45 Hz frequencies. One-way repeated measures ANOVA showed a significant decrease in PaCO 2 among the four ventilation frequency groups. Post-hoc analysis showed significant differences between 15 and 35 Hz frequencies and between 15 and 45 Hz frequencies. The mean (standard error) decrease of PaCO 2 was 10.8 (2.2), 14.1 (2.3), 21.3 (3.3), and 23.1 (2.5) mmHg at 15, 25, 35, and 45 Hz, respectively. Combination therapy of helium–oxygen gas mixture and high-frequency oscillation using ultra/very high frequencies (35–45 Hz) was associated with a greater PaCO 2 decrease than that using the standard frequency (15 Hz).

A prospective blinded, randomized controlled trial was undertaken to compare the initial response of albuterol nebulized in heliox or control in the treatment of moderately severe asthma in children presenting to a pediatric ED. Patients were randomized to receive heliox (n = 20) or control (n = 21). The primary outcome was to compare a modified dyspnea index score at 10 and 20 minutes after randomization. Secondary outcomes were to determine if heliox decreased admission rates or endotracheal intubation. There was no statistically significant difference found at 10 or 20 minutes after randomization with heliox ( P = .169 and P = .062, respectively). No statistical difference in admission rate was found, and no patients required endotracheal intubation in either group. Our results demonstrate that albuterol nebulized with heliox offered no clinical benefit over standard therapy in the initial treatment of moderately severe asthma in the ED.

The atmospheric pressure helium plasma jet driven by pulsed dc voltage was utilized to treat human lung cancer cells in vitro. The properties of plasma plume were adjusted by the injection type and flow rate of additive oxygen gas in atmospheric pressure helium plasma jet. The plasma characteristics such as plume length, electric current and optical emission spectra (OES) were measured at different flow rates of additive oxygen to helium. The plasma plume length and total current decreased with an increase in the additive oxygen flow rate. The electron excitation temperature estimated by the Boltzmann plot from several excited helium emission lines increased slightly with the additive oxygen flow. The oxygen atom density in the gas phase estimated by actinometry utilizing argon was observed to increase with the additive oxygen flow. The concentration of intracellular reactive oxygen species (ROS) measured by fluorescence assay was found to be not exactly proportional to that of extracellular ROS (measured by OES), but both correlated considerably. It was also observed that the expression levels of p53 and the phospho-p53 were enhanced in the presence of additive oxygen flow compared with those from the pure helium plasma treatment.