Heliox Therapy Presentation

My

presentation

is for

heliox

therapy

, so we heard that I'm in

therapy

as well as a special techniques part of the lecture, so I'm just going to touch on a few points, so for the story, did it develop or discovered, I should say in the late 19th century by Sir William Ramsay and its first clinical use was used by Charles Cook in 1923 and he used a mixture to decrease the risk of decompression sickness and divers and in 1934 Alvin Brock Orabrush first discovered time the airway physiology of respiratory

heliox

and advocated for Its use in a variety of diseases he discovered that labored breathing with a mixture of oxygen and helium 8020 reduced airway and intra-abdominal pressure by approximately 50%, so just about helium just a little bit of basic information so it is the most abundant element in the universe and it is only found in gas fields in North America and because helium is an inert gas it will not interact with tissue human or with any agricultural agent, so that means that inert gas is a gas that does not undergo any chemical reaction under a certain set of conditions. conditions, so it doesn't matter if, for example, it is given with a bronchodilator, it will not affect that therapy chemically, but it could help with bowel movements and other things that we will touch on later simply because of its lower density and let's see that it is never It is It is advisable to use 100% helium set just in case, for some reason, that would be the only gas that is worse and that is because we know that helium is incompatible with life.

Some other curiosities about helium: it has the lowest boiling point and melting point of any element, it is odourless, colorless and tasteless and it is also a great thermal conductor, which is why liquid helium is used to cool the superconducting coils in the magnet from an MRI scanner, sort of like a hidden Jeopardy question that needs to be left for later, and then the purpose of the heliox. therapy, so basically we're just trying to help the flow, so while the density and viscosity of oxygen, nitrogen and air are very similar, by substituting helium, which is a lower density gas, for nitrogen , the physical properties of the inhaled gas are changed, so that's what we're looking at here, basically, by decreasing the density of the gas, the resistance to airflow can be decreased in the absence of any anatomical change, so nothing more changes simply in addition to the decrease in gas density, so this simply shows up as a nice laminar flow of combustion fluid up and then. turbulent flow below, so laminar flow is nice and smooth, it can move easily, it doesn't require as much pressure to move and therefore for a given pressure difference laminar gas flow provides a higher flow rate compared with turbulent gas flow deterrent, making it more efficient.

For heliox to be effective, the helium concentration should ideally be greater than 60% and the gas must exceed or exceed the patient's inspiratory flow demands so that the heliox concentration is not diluted by ambient air and mixtures. The most common are 80/20 or 70/30 but there is also 60/40 and then in some cases (which I will talk about later) it is a 50/50 mix, so the key benefit is that it gives you time to conventional therapies so that they work a little more. the deposition of, for example, a bronchodilator and the density of the gas is more important than viscosity as a flow determining term, so while we look at that, there is not a lot of data to support the clinical application of heliox and it is not clearly defined that a lower density may help in certain cases and unfortunately with the increase in cost the availability reduces a bit so with Reynolds number this is just for a bit of a nerd right now so you may actually find that This is a lot of physics and, honestly, some of it. it was over my head so it was also on the NASA website but the Reynolds number is a ratio between inertial forces and viscous forces so looking at the change or movement with how heavy and sticky it is , for gas in the airways can be laminar turbulence or a combination of the two, so laminar flow is the most efficient way in which oxygen is delivered to the most distal parts of the bronchial tree.

The type of flow that occurs at any given point is determined by the Reynolds number and what this number is. It is a unitless quantity that is proportional to the product of the diameter of the airways and the velocity and density of the gas divided by its viscosity, so when the Reynolds number is high, for example greater than 4000, the air flow will be more turbulent and then it will continue. The flip side, when the number is low, say less than 2000, the flow will be more laminar and if you think about it, requires less effort and less resistance, so the heliox decreases the lord gradient needed to achieve a given level. of turbulent flow and In theory, this will reduce your work of breathing or the work of breathing of the patient, so for the administration of heliox the best way is through a mask without a rebreather, this allows the best concentration to be delivered to the patient without The most important thing is the mask that fits well and flows high enough to prevent entrainment of room air, so we really wanted to be just that mixture of heliox and oxygen, so one technique, which is in the book, is flow meters. - when it is heliox and then the tube is attached to a teepee placed on the mask or the heliox is attached directly to the mask without a rebreather and then oh two it is administered through a nasal cannula and the only problem with both is one is not better than the other is the precision of the helium that is delivered and that is the problem with these other forms of nasal cannula or, sorry, nasal CPAP in babies, which are also non-invasive and also invasive, which we will talk about later. since we are currently on advanced mechanical ventilation, but let's not use it only with nasal cannula, taut hoods or blenders, so disorders treated with heliox will look more at the indications, so to speak, so we are looking at post-extubation asthma, trachea, bronchi, viral tiss and laryngitis.

Larry OH trachea bronchi TISS bronchiolitis and then in addition to tumors, foreign body aspiration, vocal cord paralysis, MIA and then COPD, so basically the most common indication for heliox is upper airway obstruction and there is no direct contraindication for heliox as as we know it is an inert gas so it is not going to interact with anything so it will work or we will not see much change and it is only effective when there is turbulent flow present and I was reading in one from articles on the population that will benefit the most from this will be children with smaller airways and therefore some clinical benefits of heliox may relieve discomfort and minimize patient strain, so we are looking reduce the work of breathing and this, with this reduction in the work of breathing, will increase the airway pressure.

It will also decrease and if you remember, the trans airway pressure is the pressure difference between the mouth and the alveoli, so when this pressure is constant, the flow through the airways is greater with Ely heliox, for which will be able to flow and reach areas. which you may not have done before, that being said, heliox does not cure the cause of airway obstruction so it should simply be used in conjunction with other therapies in terms of mechanical ventilation and we will get to this in a moment, but the benefits potentials. reduces PIP in volumetric ventilation, so maximum inspiratory pressure increases CO2 removal and improves gas exchange, reduces automatic signal, increases flows and reduces rate, so if you think if we are in control of volume, the higher the percentage of helium, the lower the pip will be to achieve the tidal volume, which makes sense and then for pressure control, the tidal volume will increase with the same pressure as the percentage of helium increases. helium so I was looking at some heliox videos and frankly they were pretty boring and seemed a bit tedious without I got a lot of information so I did a mechanical vent study from Nick hoping to shed some light on some areas of it so The study investigated affective heliox in gas exchange to improve the neurological outcome of cardiac arrest, so the authors hypothesized that the use of heliox would allow greater removal of CO2 and in adults during mechanical ventilation. conventional with lower tidal volumes, so this study included 24 eligible patients, 83% were men and the average age was 65 years.

I think it started around one hundred and twenty. -nine people and for various reasons were not included in the study, so some things the subjects had to have suffered cardiac arrest outside the hospital and then were admitted to the ICU after CPR was administered, so the Inclusion criteria included spontaneous circulation within 30 days. minutes of arrest and coma on admission and some exclusion criteria included hypoxemia and a fio2 over 50 and that will make sense in a minute because we'll talk about they used a 5050 heliox mix so if the fio2 needed to be higher In addition to that, that would be a problem out of 10 for neurological disorders of severe pregnancy disability and then if they had a comorbidity with a life expectancy of less than 6 months, they were excluded from the study, so now that's all out of the way So what was analyzed before starting heliox.

The patients were pressure controlled ventilated with a servo I and were started on the protocol within 5 hours of their cardiac arrest, so the heliox mixture they used was 5050. They used a target tidal volume of 6 milliliters per kilogram. They made no changes to the fio2 or peep IDE and the treatment was provided for three hours before returning to the normal Oh to air mix. Additionally, the study continued: all patients were treated with therapeutic hypothermia for sedation with propofol and opioids were used. They did not clarify which opioids were used and neuromuscular relaxants were administered as a bolus, but only during shivering, the respiratory rate was adjusted to reach the specific pH, so it was within a normal range, as well as the paco2, which results in a significant decrease. at the frequency intended to decrease the minute volume of ventilation vault after discontinuation of heliox therapy, the new parameters did not change and the tidal volume remained stable at six milliliters per kilogram, the maximum pressure tended to decrease and The gross, dynamic loss of lung compliance by the ventilator did not change during heliox ventilation, so some things that stood out at least a little here is that when switching from oxygen and air to heliox there was a rapid decrease in PA CO2 level which increased again after the heliox treatment was completed so you will be able to look at the graph and you will have to excuse my x axis which is PA co2 so as you go you will see it decrease during those three hours, but as soon as the heliox treatment is stopped, the trend increases again, so there was also an increase in pH shortly after application.

Oxygenation was not significantly altered after starting heliox or after changing it again, so it had no effect. Applied fio2 levels remained between 40 and 50, while PA o2 levels tended to decrease somewhat. Somewhat, the heliox improved ventilation by allowing lower minute ventilation while PA CO2 levels decreased and just on that note, the CO2 diffuses more rapidly through the heliox than just the normal #nitrogen mix. 2, so it would make sense that it would diffuse and taper off while treatment was ongoing, so should heliox be used in mechanically ventilated patients? So there isn't a large randomized study of heliox in mechanically ventilated patients and that's something that I've come across a lot in the literature and there just isn't a lot of evidence.

In a pediatric model, heliox 70/30 provided better deposition in the operating room, all from an MDI, and these studies support that heliox can improve aerosol delivery and to mechanically ventilated patients with severe airway obstruction. When observing mechanically ventilated asthmatic patients, they demonstrated rapid airway narrowing. Blood pressure improved carbon dioxide removal and resolution of acidosis and then, in COPD patients who were also intubated, they experienced a reduction in peak airway pressure and mean airway pressure. That said, many of the improvements were reversed once heliox treatment ended.discontinued and then just some considerations, things that came to mind while I was doing this and that is that there are really no guidelines, here is the length of time it should be done, here is the exact mixture that will be used, our protocols, these are studies that we can continue with. that tends to be useless when trying to determine usage and then would also involve longer use of heliox during hospital stays during conventional treatment lessons, so I was thinking if I used it and reduced the pressure a little or reduced the breathing a little bit, but that ultimately helps the patient overall or since everything goes back to how it was before the treatment, it really makes a difference, so I think more research needs to be done and see if it really helps others conventional therapies. does it work better or help with a shorter treatment so thanks for listening although heliox may not show real improvement especially once it is stopped if done for three hours does it help patients when their work decreases respiratory?

Tell if you know that heliox is used once a day. for five days or come up with some kind of protocol that would actually reduce their work of breathing or give them time to lower their CO2 levels if that was what was necessary or to lower their pressures with the treatment time being less than it would otherwise be. way so I'm not sure there is enough evidence to show whether or not it would help long term as the numbers always seem to go back to what they were before the treatment started so does it really help or not?

Something to think about. If you have any questions you can leave them in the little comment and I will do my best to answer them, but thanks for listening.