Effects of heliox and non-invasive neurally adjusted ventilatory assist (NIV-NAVA) in preterm infants.

Due to its unique properties, helium-oxygen (heliox) mixtures may provide benefits during non-invasive ventilation, however, knowledge regarding the effects of such therapy in premature infants is limited. This is the first report of heliox non-invasive neurally adjusted ventilatory assist (NIV-NAVA) ventilation applied in neonates born ≤ 32 weeks gestational age. After baseline NIV-NAVA ventilation with a standard mixture of air and oxygen, heliox was introduced for 3 h, followed by 3 h of air-oxygen. Heart rate, peripheral capillary oxygen saturation, cerebral oxygenation, electrical activity of the diaphragm (Edi) and selected ventilatory parameters (e.g., respiratory rate, peak inspiratory pressure) were continuously monitored. We found that application of heliox NIV-NAVA in preterm infants was feasible and associated with a prompt and significant decrease of Edi suggesting reduced respiratory effort, while all other parameters were stable throughout the study, and had similar values during heliox and air-oxygen ventilation. This therapy may potentially enhance the efficacy of non-invasive respiratory support in preterm neonates and reduce the number of infants progressing to ventilatory failure.

Percutaneous Argon-Helium Cryoablation for Small Hepatocellular Carcinoma Located Adjacent to a Major Organ or Viscus: A Retrospective Study of 92 Patients at a Single Center.

BACKGROUND Cryoablation of hepatocellular carcinoma (HCC) close to major organs or viscus is challenging because it can cause complications. This retrospective study aimed to investigate the safety and efficacy of percutaneous argon-helium cryoablation of small HCC located adjacent to major organs or viscus. MATERIAL AND METHODS Ninety-two patients who underwent percutaneous argon-helium cryoablation between February 2012 and December 2018 at the Fifth Medical Center of the Chinese People's Liberation Army General Hospital were included. Treatment efficacy was evaluated by magnetic resonance imaging or triphasic computed tomography scan within 1 week after each cryoablation procedure. Local tumor progression, distant recurrence, and overall survival were analyzed using the Kaplan-Meier method and log-rank test. RESULTS A total of 92 patients with small HCC located adjacent to major organs or viscus who underwent cryoablation were retrospectively reviewed. The number of patients with tumors adjacent to the gallbladder, portal or hepatic vein, diaphragm, stomach, heart, and intestine was 22, 1, 39, 6, 8, and 16, respectively. Cumulative local tumor progression rates at 1 and 2 years were 2.8% and 7.3%, respectively. Cumulative distant recurrence rates at 1, 2, and 3 years were 11.1%, 17.6%, and 20.7%, respectively. The overall survival rates at 1, 2, and 4 years were 100%, 93.6%, and 74.9%, respectively. Major complications were observed in 5 (5.4%) patients. Minor complications were observed in 85 (92.4%) patients. CONCLUSIONS This experience from a single center showed that percutaneous argon-helium cryoablation was safe and effective in the management of small HCC that is located adjacent to major organs or viscus.

Heliox for croup in children.

BACKGROUND: Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (the benefits of which are often delayed) and nebulised epinephrine (adrenaline) (the benefits of which may be short-lived and which can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation. A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress. This review updates versions published in 2010, 2013, and 2018. OBJECTIVES: To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation. SEARCH METHODS: We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE, Embase, CINAHL, Web of Science, and LILACS, on 15 April 2021. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 15 April 2021. We contacted the British Oxygen Company, a leading supplier of heliox. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo, no treatment, or any active intervention(s) in children with croup. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Data that could not be pooled for statistical analysis were reported descriptively. MAIN RESULTS: We included 3 RCTs involving a total of 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months, and all studies were conducted in emergency departments. Two studies were conducted in the USA and one in Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study because of its open-label design. We did not identify any new trials for this 2021 update. One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70) (Westley croup score, scale range 0 to 16). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low certainty, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported. In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve Taussig croup scores (scale range 0 to 15) at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -1.56 to 0.16). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be a difference in hospitalisation rates between groups (odds ratio 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to imprecision and high risk of bias related to an open-label design. Information on heart rate and intubation was not reported. In the third study, 29 children with moderate to severe croup all received continuous cool mist and intramuscular dexamethasone (0.6 mg/kg). They were then randomised to receive either heliox (given as a mixture of 70% helium and 30% oxygen) plus one to two doses of nebulised saline or 100% oxygen plus nebulised epinephrine (adrenaline), with gas therapy administered continuously for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may result in little or no difference overall using repeated-measures analysis. We assessed the evidence for all outcomes in this comparison as of low certainty, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported. The included studies did not report on adverse events, intensive care admissions, or parental anxiety. We could not pool the available data because each comparison included data from only one study. AUTHORS' CONCLUSIONS: Given the very limited available evidence, uncertainty remains regarding the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate croup treated with dexamethasone. The effect of heliox may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.

Thermovaccination - thermoheliox as a stimulator of the immune response. Kinetics of the synthesis of antibodies and C-reactive protein in coronavirus infection.

Clinical trials of thermoheliox application (inhalation with a high-temperature mixture of oxygen and helium, 90 °C) in the treatment of the acute phase of coronavirus infection were conducted. Dynamics of disease development in infected patients (PCR test for the virus) and, dynamics of changes in blood concentration of C-reactive protein, immunoglobulin M, specific immunoglobulin G were studied. High efficiency of thermoheliox in releasing the organism from the virus and stimulating the immune response (thermovaccination effect) was shown. The kinetic model of the process is proposed and analyzed.

Helium inhalation injuries managed at emergency departments.

INTRODUCTION: Helium is a colorless, odorless, and tasteless inert gas. Inhaling helium can temporarily result in a high-pitched, squeaky voice. Individuals also may inhale helium to become intoxicated or commit suicide. The objective of this study was to characterize helium inhalations managed at emergency departments (EDs). METHODS: Data were obtained from the National Electronic Injury Surveillance System (NEISS), a database of consumer product-related injuries collected from the EDs of approximately 100 United States hospitals. Helium inhalation-related injuries reported during 2000-2019 were identified by reviewing the record narratives for the term "helium." The distribution of the national estimate was determined for selected variables. RESULTS: A total of 89 helium inhalation-related injuries were identified, resulting in a national estimate of 2,186 injuries. The estimated number of injuries was 99 during 2000-2004, 305 during 2005-2009, 864 during 2010-2014, and 918 during 2015-2019. The age distribution was 75 (3.4%) 0-5 years, 1,427 (65.3%) 6-12 years, 586 (26.8%) 13-19 years, and 98 (4.5%) 20 years or older; 1446 (66.1%) of the patients were male. The most commonly reported symptoms or injuries were 1500 (68.6%) syncope, 615 (28.1%) non-concussion head injury, 299 (13.7%) dizziness/lightheaded, 267 (12.2%) contusion/abrasion, and 236 (10.8%) concussion. The patient was treated or evaluated and released in 2149 (98.3%) estimated injuries. CONCLUSION: The majority of patients with helium inhalation-related injuries treated at United States EDs were age 6-12 years and male. Most of the patients experienced either syncope or dizziness/lightheadedness and were released from the ED.

End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum.

BACKGROUND: Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe ). METHODS: Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. RESULTS: Significant correlations were found between EELV CO 2 and EELVHe before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELVHe and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELVHe and LCI showed a curvilinear relationship, and an EELVHe of approximately 20 mL kg-1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values. CONCLUSION: In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg-1 .

Cold atmospheric plasma modulates endothelial nitric oxide synthase signalling and enhances burn wound neovascularisation.

Treatment with cold atmospheric plasma (CAP) has been reported to promote wound healing in animals. However, how this process is mediated remains unclear. In this study we examined the mechanisms which underlie the improved wound healing effects of CAP and the roles of associated reactive oxygen and nitrogen species (RONS), which are generated by plasma. By using in vitro models which mimicked various steps of angiogenesis, we demonstrated that CAP triggered the production of nitric oxide (NO), and enhanced cell migration and the assembly of endothelial cells into vessel-like structures. These are both hallmarks of the proliferative phase of wound healing. Using a mouse model of a third-degree burn wound, we went on to show that CAP treatment was associated with enhanced angiogenesis, characterised by accelerated in vivo wound healing and increased cellular proliferation. Here, CAP significantly increased the in vivo production of endothelial NO synthase (eNOS), an enzyme that catalyses NO synthesis in endothelial cells, and significantly increased the expression of pro-angiogenic PDGFRß and CD31 markers in mouse wounds. Mechanistically, we showed that CAP induced eNOS phosphorylation and activation, thereby increasing the levels of endogenous NO in endothelial cells. Increased NO generation facilitated by CAP further stimulated important pro-angiogenic VEGFA/VEGFR2 signalling in vitro. This proof-of-concept study may guide future efforts aimed at addressing the use of physical plasma and its therapeutic applications in a variety of pathological scenarios. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Comparison of various types of inert gas components on efficacy of an alveolar recruitment maneuver in dorsally recumbent anesthetized horses.

OBJECTIVE: To assess effects of nitrogen and helium on efficacy of an alveolar recruitment maneuver (ARM) for improving pulmonary mechanics and oxygen exchange in anesthetized horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were anesthetized twice in a randomized crossover study. Isoflurane-anesthetized horses in dorsal recumbency were ventilated with 30% oxygen and 70% nitrogen (treatment N) or heliox (30% oxygen and 70% helium; treatment H) as carrier gas. After 60 minutes, an ARM was performed. Optimal positive end-expiratory pressure was identified and maintained for 120 minutes. Throughout the experiment, arterial blood pressures, heart rate, peak inspiratory pressure, dynamic compliance (Cdyn), and Pao2 were measured. Variables were compared with baseline values and between treatments by use of an ANOVA. RESULTS: The ARM resulted in significant increases in Pao2 and Cdyn and decreases in the alveolar-arterial gradient in the partial pressure of oxygen in all horses. After the ARM and during the subsequent 120-minute phase, mean values were significantly lower for treatment N than treatment H for Pao2 and Cdyn. Optimal positive end-expiratory pressure was consistently 15 cm H2O for treatment N, but it was 10 cm H2O (4 horses) and 15 cm H2O (2 horses) for treatment H. CONCLUSIONS AND CLINICAL RELEVANCE: An ARM in anesthetized horses might be more efficacious in improving Pao2 and Cdyn when animals breathe helium instead of nitrogen as the inert gas.

High flow nasal cannula: Influence of gas type and flow rate on airway pressure and CO2 clearance in adult nasal airway replicas.

BACKGROUND: High flow nasal cannula therapy is a form of respiratory support which delivers high flow rates of heated, humidified gas to the nares via specialized cannula. Two primary mechanisms of action attributed to the therapy are the provision of positive airway pressure as well as clearance of CO2-rich exhaled gas from the upper airways. METHODS: Physiologically accurate nose-throat airway replicas were connected at the trachea to a lung simulator, where CO2 was supplied to mimic the CO2 content in exhaled gas. Cannula delivered either air, oxygen or heliox (80/20%volume helium/oxygen) to the replicas at flow rates ranging from 0 to 60 l/min. Five replicas and three cannulas were compared. Tracheal pressure and CO2 concentration were continuously measured. The lung simulator provided breaths with tidal volume of 500 ml and frequency of 18 breaths/min. Additional clearance measurements were conducted for tidal volume and breathing frequency of 750 ml and 27 breaths/min, respectively. FINDINGS: Cannula flow rate was the dominant factor governing CO2 concentration. Average CO2 concentration decreased with increasing cannula flow rate, but above 30 L/min this effect was less pronounced. Tracheal positive end-expiratory pressure increased with flow rate and was lower for heliox than for air or oxygen. A predictive correlation was developed and used to predict positive end-expiratory pressure for a given cannula size as a function of supplied flow rate and occlusion of the nares. INTERPRETATION: Compared with administration of air or oxygen, administration of heliox is expected to result in similar CO2 clearance from the upper airway, but markedly lower airway pressure.

Plasma from Volunteers Breathing Helium Reduces Hypoxia-Induced Cell Damage in Human Endothelial Cells-Mechanisms of Remote Protection Against Hypoxia by Helium.

PURPOSE: Remote ischemic preconditioning protects peripheral organs against prolonged ischemia/reperfusion injury via circulating protective factors. Preconditioning with helium protected healthy volunteers against postischemic endothelial dysfunction. We investigated whether plasma from helium-treated volunteers can protect human umbilical vein endothelial cells (HUVECs) against hypoxia in vitro through release of circulating of factors. METHODS: Healthy male volunteers inhaled heliox (79% helium, 21% oxygen) or air for 30 min. Plasma was collected at baseline, directly after inhalation, 6 h and 24 h after start of the experiment. HUVECs were incubated with either 5% or 10% of the plasma for 1 or 2 h and subjected to enzymatically induced hypoxia. Cell damage was measured by LDH content. Furthermore, caveolin 1 (Cav-1), hypoxia-inducible factor (HIF1α), extracellular signal-regulated kinase (ERK)1/2, signal transducer and activator of transcription (STAT3) and endothelial nitric oxide synthase (eNOS) were determined. RESULTS: Prehypoxic exposure to 10% plasma obtained 6 h after helium inhalation decreased hypoxia-induced cell damage in HUVEC. Cav-1 knockdown in HUVEC abolished this effect. CONCLUSIONS: Plasma of healthy volunteers breathing helium protects HUVEC against hypoxic cell damage, possibly involving circulating Cav-1.

A proof-of-concept trial of HELIOX with different fractions of helium in a human study modeling upper airway obstruction.

BACKGROUND: Helium in oxygen (HELIOX) can relieve airway obstruction and lower the work of breathing because it increases the threshold at which turbulent gas flow is induced. Less turbulent and more laminar flow lowers the work of breathing. According to guidelines, the fraction of Helium in HELIOX should be maximized (e.g. to 79%). Here, we investigate whether HELIOX with less than 60% of Helium is able to relieve the sensation of dyspnea in healthy volunteers. METHODS: 44 volunteers underwent resistive loading breathing different gases (medical air and HELIOX with a fraction of 25%, 50% or 75% helium in oxygen) in a double-blinded crossover design. Subjects rated their degree of dyspnea (primary outcome parameter) and the variability of noninvasively measured systolic blood pressure was assessed. RESULTS: Dyspnea was significantly reduced by HELIOX-containing mixtures with a fraction of helium of 25% or more. Similarly, blood pressure variability was reduced significantly even with helium 25% during respiratory loading with the higher load, whereas with the smaller load an effect could only be obtained with the highest helium fraction of 75%. CONCLUSION: In this clinical trial, HELIOX with less than 60% of helium in oxygen decreased the sensation of dyspnea and blood pressure variability, a surrogate parameter for airway obstruction. Therefore, higher oxygen fractions might be applied without losing the helium-related benefits for the treatment of upper airway obstruction. TRIAL REGISTRATION: Registration with clinical trials (NCT00788788) and EMA (EudraCT number: 2006-005289-37).

Effects of head-only or whole-body exposure to very low doses of 4He (1000 MeV/n) particles on neuronal function and cognitive performance.

On exploratory class missions, astronauts will be exposed to a range of heavy particles which vary in linear energy transfer (LET). Previous research has shown a direct relationship between particle LET and cognitive performance such that, as particle LET decreases the dose needed to affect cognitive performance also decreases. Because a significant portion of the total dose experienced by astronauts may be expected to come from exposure to low LET 4He particles, it would be important to establish the threshold dose of 4He particles that can produce changes in cognitive performance. The results indicated that changes in neuronal function and cognitive performance could be observed following both head-only and whole-body exposures to 4He particles at doses as low as 0.01-0.025 cGy. These results, therefore, suggest the possibility that astronauts on exploratory class missions may be at a greater risk for HZE-induced deficits than previously anticipated.

Evaluation of the effects of gas volume and composition on accuracy of volume measurement by two flow sensors and delivery by a piston-driven large-animal ventilator.

OBJECTIVE To evaluate the effects of 4 gas compositions at various volumes (simulated tidal volumes [VTs]) on accuracy of measurements obtained with 2 types of flow sensors and accuracy of gas volume delivery by a piston-driven ventilator. SAMPLE 4 gas mixtures (medical air [21% O2:79% N2], > 95% O2, O2-enriched air [30% O2:70% N2], and heliox [30% O2:70% He]). PROCEDURES For each gas mixture, reference VTs of 1 to 8 L were delivered into an anesthetic breathing circuit via calibration syringe; measurements recorded by a Pitot tube-based flow sensor (PTFS) connected to a multiparameter host anesthesia monitor and by a thermal mass flow and volume meter (TMFVM) were compared with the reference values. Following leak and compliance testing, the ventilator was preset to deliver each gas at VTs of 1 to 8 L into the calibration syringe. Effects of gas volume and composition on accuracy of VT measurement and delivery were assessed by ANOVA. Agreements between delivered and flow sensor-measured VT and preset versus ventilator-delivered VT were determined by Bland-Altman analysis. RESULTS Flow sensor measurements were accurate and not influenced by gas composition. Mean measurement error ranges for the PTFS and TMFVM were -4.99% to 4.21% and -4.50% to 0.17%, respectively. There were no significant differences between ventilator-delivered and reference VTs regardless of gas volume or composition. Bland-Altman analysis yielded biases of -0.046 L, -0.007 L, -0.002 L, and 0.031 L for medical air, > 95% O2, O2-enriched air, and heliox, respectively. CONCLUSIONS AND CLINICAL RELEVANCE The PTFS and the TMFVM measured VTs and the piston-driven ventilator delivered VTs with error rates of < 5% for all gas compositions and volumes tested.

¿Mejora la administración de helio mediante cánula nasal de bajo flujo la dificultad respiratoria en lactantes con bronquiolitis aguda por virus respiratorio sincitial? Estudio aleatorizado controlado / Does heliox administered by low-flow nasal cannula improve respiratory distress in infants with respiratory syncytial virus acute bronchiolitis? A randomized controlled trial

OBJETIVOS: El objetivo del estudio fue evaluar si el uso de heliox (79:21) administrado vía cánula nasal de bajo flujo mejora el trabajo respiratorio en lactantes con bronquiolitis aguda causada por virus respiratorio sincitial. MÉTODOS: Se realizó un estudio prospectivo aleatorizado controlado. Todos los pacientes que cumplieron los criterios de inclusión se asignaron al azar a tratamiento con heliox (79:21) o con aire, administrados mediante cánula nasal a razón de 2 L/min durante un período ininterrumpido de 24 h. Se realizaron medidas basales, a las 2 h de iniciar el tratamiento y al completarse las 24 h. RESULTADOS: Se incluyeron 104 pacientes en el estudio. No se observaron diferencias significativas en la puntuación de la M-WCAS entre los dos grupos a las 2 h (4,3 vs. 4,1; p = 0,78) o al completarse las 24 h (4,2 vs. 4,3; p = 0,89). No hubo diferencias en las proporciones de participantes que progresaron a ventilación mecánica, CPAP-n u oxigenoterapia administrada mediante cánula nasal (RR: 1,0, 0,86 y 0,89; p = 1,0, 0,77 y 0,73). No hubo una reducción significativa en la duración de tratamiento, de 2,42 días en el grupo tratado con heliox y de 2,79 días en el grupo tratado con aire (p = 0,65). Tampoco hubo diferencias significativas entre los dos grupos bajo estudio en la saturación de oxígeno, PaO2 o PaCO2 a las 2 y a las 24 h de tratamiento. CONCLUSIONES: Nuestros datos no mostraron ningún efecto beneficioso del heliox a una concentración de 79:21 administrado vía cánula nasal de bajo flujo en cuanto a la mejoría de la dificultad respiratoria en lactantes con bronquiolitis aguda por VRS

OBJECTIVES: The aim of our study is to evaluate whether the use of heliox (79:21) delivered through a low flow nasal cannula would improve respiratory distress in infants with acute bronchiolitis caused by respiratory syncytial virus. METHODS: We have conducted a prospective randomized controlled study. All patients fulfilled inclusion criteria were randomized to either heliox (79:21) or air via NC at 2 L/min for a continuous 24 hours. Measurements were taken at baseline, after 2hours and at the end of the 24hours. RESULTS: We have included 104 patients into our study. The MCA-S did not show any significant difference between the two groups after 2hours 4.3 vs. 4.1 (P =.78), or at 24hours after 4.2 vs. 4.3 (P =.89). No difference was found in the proportion of participants progressed to MV, n-CPAP or oxygen via nasal cannula (RR 1.0, 0.86 and 0.89) (P= 1.0, .77 and .73). There was no notable reduction in length of treatment in Heliox group 2.42 days vs. 2.79 days in air group P =.65. The in oxygen saturation, PaO2, and PaCO2 did not to have any statistical difference between the two studied groups after 2 hours and 24 hours of treatment. CONCLUSION: Our data showed absence of any beneficial effect of heliox in a concentration (79:21) delivered through low flow nasal cannula in terms of respiratory distress improvement in infants with RSV acute bronchiolitis

The effect of inhaled heliox on peak flow rates in normal and brachycephalic dogs.

BACKGROUND: Heliox, a mixture of helium and oxygen, alleviates airway obstruction in people and improves air flow, and its use has been proposed in dogs. Brachycephalic dogs have naturally occurring airway obstruction where heliox might be a useful therapeutic option. OBJECTIVE: The purposes of this study were to (1) determine the impact of breathing heliox on peak inspiratory and expiratory flows (PIF/PEF) in healthy dogs and (2) determine if brachycephalic dogs and mesocephalic dogs have similar responses to inhaled heliox. ANIMALS: Eleven healthy dogs: 5 mesocephalic and 6 brachycephalic dogs. METHODS: A prospective study. Tidal breathing flow-volume loops were recorded when dogs were breathing room air (nitrogen-oxygen) and heliox. Peak inspiratory and expiratory flow rates were recorded and the subjective shape of loops assessed. Peak inspiratory and expiratory flows pre- and post-heliox were compared using a Mann-Whitney Rank sum test with a P-value of <.05 considered significant. RESULTS: In inhaled heliox, PIF and PEF were evaluated by tidal breathing flow-volume loops. In mesocephalic dogs, PIF increased from a median of 820 mL/s (range, 494-1010 mL/s) to 1386 mL/s; P = .02; and for PEF from 688 mL/s to 1793 mL/s (P = .04), whereas in brachycephalic dogs, the median PIF increased from 282 mL/s to 694 mL/s; P = .01 and the median PEF increased from 212 mL/s to 517 mL/sec; P = .03. Brachycephalic dogs showed normalization of loop shapes. CONCLUSIONS AND CLINICAL IMPORTANCE: Heliox improves flow rate and appears to improve flow patterns in brachycephalic dogs.

[Does heliox administered by low-flow nasal cannula improve respiratory distress in infants with respiratory syncytial virus acute bronchiolitis? A randomized controlled trial]. / ¿Mejora la administración de helio mediante cánula nasal de bajo flujo la dificultad respiratoria en lactantes con bronquiolitis aguda por virus respiratorio sincitial? Estudio aleatorizado controlado.

OBJECTIVES: The aim of our study is to evaluate whether the use of heliox (79:21) delivered through a low flow nasal cannula would improve respiratory distress in infants with acute bronchiolitis caused by respiratory syncytial virus. METHODS: We have conducted a prospective randomized controlled study. All patients fulfilled inclusion criteria were randomized to either heliox (79:21) or air via NC at 2 L/min for a continuous 24hours. Measurements were taken at baseline, after 2hours and at the end of the 24hours. RESULTS: We have included 104 patients into our study. The MCA-S did not show any significant difference between the two groups after 2hours 4.3 vs. 4.1 (P =.78), or at 24hours after 4.2 vs. 4.3 (P =.89). No difference was found in the proportion of participants progressed to MV, n-CPAP or oxygen via nasal cannula (RR 1.0, 0.86 and 0.89) (P= 1.0, .77 and .73). There was no notable reduction in length of treatment in Heliox group 2.42 days vs. 2.79 days in air group P =.65. The in oxygen saturation, PaO2, and PaCO2 did not to have any statistical difference between the two studied groups after 2hours and 24hours of treatment. CONCLUSION: Our data showed absence of any beneficial effect of heliox in a concentration (79:21) delivered through low flow nasal cannula in terms of respiratory distress improvement in infants with RSV acute bronchiolitis.

Use of Helium/Oxygen Mixture in Noninvasive Ventilation During Urgent Tracheotomy for Upper Airway Compression: A Case Report.

Ventilation or oxygenation can be difficult or even impossible in cases of upper airway obstruction. In this case report, we used a helium/oxygen mixture administered via noninvasive positive-pressure ventilation to perform an urgent tracheotomy under local anesthesia on a patient presenting upper airway compression. It improved his comfort and his stridor, facilitating supine positioning. This case describes another potential indication of the helium/oxygen mixture in noninvasive ventilation.

Three-dimensional Isotropic Functional Imaging of Cystic Fibrosis Using Oxygen-enhanced MRI: Comparison with Hyperpolarized 3He MRI.

Purpose To compare the performance of three-dimensional radial ultrashort echo time (UTE) oxygen-enhanced (OE) MRI with that of hyperpolarized helium 3 (3He) MRI with respect to quantitative ventilation measurements in patients with cystic fibrosis (CF). Materials and Methods In this prospective study conducted from June 2013 to May 2015, 25 participants with CF aged 10-55 years (14 male; age range, 13-55 years; 11 female; age range, 10-37 years) successfully underwent pulmonary function tests, hyperpolarized 3He MRI, and OE MRI. OE MRI used two sequential 3.5-minute normoxic and hyperoxic steady-state free-breathing UTE acquisitions. Seven participants underwent imaging at two separate examinations 1-2 weeks apart to assess repeatability. Regional ventilation was quantified as ventilation defect percentage (VDP) individually from OE MRI and hyperpolarized 3He MRI by using the same automated quantification tool. Bland-Altman analysis, intraclass correlation coefficient (ICC), Spearman correlation coefficient, and Wilcoxon signed-rank test were used to evaluate repeatability. Results In all 24 participants, the global VDP measurements from either OE MRI (ρ = -0.66, P < .001) or hyperpolarized 3He MRI (ρ = -0.75, P < .001) were significantly correlated with the percentage predicted forced expiratory volume in 1 second. VDP reported at OE MRI was 5.0% smaller than (P = .014) but highly correlated with (ρ = 0.78, P < .001) VDP reported at hyperpolarized 3He MRI. Both OE MRI-based VDP and hyperpolarized 3He MRI-based VDP demonstrated good repeatability (ICC = 0.91 and 0.95, respectively; P ≤ .001). Conclusion In lungs with cystic fibrosis, ultrashort echo time oxygen-enhanced MRI showed similar performance compared with hyperpolarized 3He MRI for quantitative measures of ventilation defects and their repeatability. © RSNA, 2018 Online supplemental material is available for this article.

Helium-oxygen mixture: clinical applicability in an intensive care unit.

OBJECTIVE: To evaluate if distress respiratory decreases after using helium-oxygen mixture in pediatric patients diagnosed with bronchospasm. METHODS: This is a retrospective, non-randomized study that included patients diagnosed with bronchospasm, who received a helium-oxygen mixture at three time points (30, 60, and 120 minutes) according to the organization protocol singular, and were admitted to the intensive care unit, from January 2012 to December 2013. This protocol includes patients with bronchospasm who sustained a modified Wood score of moderate to severe, even after one hour of conventional treatment. RESULTS: Twenty children were included in the study. The mean score of severity of the disease at the initial moment was 5.6 (SD:2.0), and at moment 120 minutes, it was 3.4 (SD: 2.0). The severity score showed a significant improvement as of 30 minutes (p<0.001). CONCLUSION: The use of helium-oxygen mixture proved to be effective in diminishing the respiratory distress score for children with airway obstructions; it should be considered a supplementary therapeutic option, together with drug therapy, in specific clinical situations.

Heliox for croup in children.

BACKGROUND: Croup is an acute viral respiratory infection with upper airway mucosal inflammation that may cause respiratory distress. Most cases are mild. Moderate to severe croup may require treatment with corticosteroids (from which benefits are often delayed) and nebulised epinephrine (adrenaline) (which may be short-lived and can cause dose-related adverse effects including tachycardia, arrhythmias, and hypertension). Rarely, croup results in respiratory failure necessitating emergency intubation and ventilation.A mixture of helium and oxygen (heliox) may prevent morbidity and mortality in ventilated neonates by reducing the viscosity of the inhaled air. It is currently used during emergency transport of children with severe croup. Anecdotal evidence suggests that it relieves respiratory distress.This review updates versions published in 2010 and 2013. OBJECTIVES: To examine the effect of heliox compared to oxygen or other active interventions, placebo, or no treatment, on relieving signs and symptoms in children with croup as determined by a croup score and rates of admission and intubation. SEARCH METHODS: We searched CENTRAL, which includes the Cochrane Acute Respiratory Infections Group's Specialised Register; MEDLINE; Embase; CINAHL; Web of Science; and LILACS in January and February 2018. We also searched the World Health Organization International Clinical Trials Registry Platform (apps.who.int/trialsearch/) and ClinicalTrials.gov (clinicaltrials.gov) on 8 February 2018. We contacted British Oxygen Company, a leading supplier of heliox (BOC Australia 2017). SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs comparing the effect of heliox in comparison with placebo or any active intervention(s) in children with croup. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We reported data that could not be pooled for statistical analysis descriptively. MAIN RESULTS: We included 3 RCTs with 91 children aged between 6 months and 4 years. Study duration was from 7 to 16 months; all studies were conducted in emergency departments in the USA (two studies) and Spain. Heliox was administered as a mixture of 70% heliox and 30% oxygen. Risk of bias was low in two studies and high in one study due to an open-label design. We added no new trials for this update.One study of 15 children with mild croup compared heliox with 30% humidified oxygen administered for 20 minutes. There may be no difference in croup score changes between groups at 20 minutes (mean difference (MD) -0.83, 95% confidence interval (CI) -2.36 to 0.70). The mean croup score at 20 minutes postintervention may not differ between groups (MD -0.57, 95% CI -1.46 to 0.32). There may be no difference between groups in mean respiratory rate (MD 6.40, 95% CI -1.38 to 14.18) and mean heart rate (MD 14.50, 95% CI -8.49 to 37.49) at 20 minutes. The evidence for all outcomes in this comparison was of low quality, downgraded for serious imprecision. All children were discharged, but information on hospitalisation, intubation, or re-presenting to emergency departments was not reported.In another study, 47 children with moderate croup received one dose of oral dexamethasone (0.3 mg/kg) with either heliox for 60 minutes or no treatment. Heliox may slightly improve croup scores at 60 minutes postintervention (MD -1.10, 95% CI -1.96 to -0.24), but there may be no difference between groups at 120 minutes (MD -0.70, 95% CI -4.86 to 3.46). Children treated with heliox may have lower mean Taussig croup scores at 60 minutes (MD -1.11, 95% CI -2.05 to -0.17) but not at 120 minutes (MD -0.71, 95% CI -1.72 to 0.30). Children treated with heliox may have lower mean respiratory rates at 60 minutes (MD -4.94, 95% CI -9.66 to -0.22), but there may be no difference at 120 minutes (MD -3.17, 95% CI -7.83 to 1.49). There may be no difference in hospitalisation rates between groups (OR 0.46, 95% CI 0.04 to 5.41). We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to imprecision and high risk of bias related to open-label design. Information on heart rate and intubation was not reported.In the third study, 29 children with moderate to severe croup received intramuscular dexamethasone (0.6 mg/kg) and either heliox with one to two doses of nebulised saline, or 100% oxygen with one to two doses of adrenaline for three hours. Heliox may slightly improve croup scores at 90 minutes postintervention, but may have little or no difference overall using repeated measures analysis. We assessed the evidence for all outcomes in this comparison as of low quality, downgraded due to high risk of bias related to inadequate reporting. Information on hospitalisation or re-presenting to the emergency department was not reported.The included studies did not report on adverse events, intensive care admissions, or parental anxiety.We could not pool the available data because each comparison included data from only one study. AUTHORS' CONCLUSIONS: Due to very limited evidence, uncertainty remains about the effectiveness and safety of heliox. Heliox may not be more effective than 30% humidified oxygen for children with mild croup, but may be beneficial in the short term for children with moderate to severe croup treated with dexamethasone. The effect may be similar to 100% oxygen given with one or two doses of adrenaline. Adverse events were not reported, and it is unclear if these were monitored in the included studies. Adequately powered RCTs comparing heliox with standard treatments are needed to further assess the role of heliox in the treatment of children with moderate to severe croup.