High flow nasal cannula therapy

追加: 2026-05-08

[00:00:01]Coming to humidified high flow nasal cannula, here it's a gas flow of 2 to 8 L in the newborn period. Of course, in children we go up to 30 L. And it's a mixture of air and oxygen given by a the blender. So, we have discussed previously as well never give any form of ventilation without using a blender because 100% oxygen is harmful. If you are ventilating a baby, you need to be able to titrate the oxygen delivery to what is needed based on the saturation target. You know that the saturation target in babies is 90 to 94%. Your alarm limits are adjusted one or two below or above that.

[00:00:35]And if a baby has a PPHN or meconium aspiration with a risk of PPHN, you can accept up to 97% saturation, not more than that.

[00:00:44]And always allow the nurses to titrate the oxygen. Don't wait for orders to be So, always if they see the saturation above 95, they trickle down the oxygen.

[00:00:53]Keep lowering it and if the oxygen is really dropped, that means you have to start lowering the pressure as well.

[00:00:59]High flow has been shown to generate positive pressure in the airways.

[00:01:03]The PEEP generated depends on the flow rate, the prong size, and the size of the baby. Obviously, the prong size should have a 50% leak and it should not have a snug fit.

[00:01:14]So, there are a few studies which have looked at the comparison of the air flow with the pressure delivered in the airway and the same size of baby as you increase the flow, the pressure goes up. But as you can see here, according to the size of the baby, the pressure varies. So, 500 g baby, the same flow can reach 4 L can reach 4 cm pressure.

[00:01:37]While in a bigger baby, a 4 L flow can give 2.5 to 3 pressure. So, obviously, size of the baby uh it's related to the Laplace's law where the leak is going to depend on the size of the nostril and the leak around it.

[00:01:56]So, the main disadvantage of high flow and the reason most of us are not keen on using it as a primary mode is because the pressures are not measured. You're guessing the pressure.

[00:02:05]In CPAP as well, you can argue that it's not really that the pressure is measured. We think that's the pressure reaching the baby, but there are many variables like the way the snug fit is there.

[00:02:14]If the baby is opening the mouth, the pressure drops as well. And if there is secretions in the airway, uh nasal passage isn't clear, the pressure doesn't reach the lungs.

[00:02:23]So, this is a relative disadvantage.

[00:02:26]But the main disadvantage is that the flexibility, the amount to which you can increase the pressure is lower with high flow, especially because we follow a limit of 8 L for newborns.

[00:02:36]We have uh different devices, the Vapotherm, which is a cartridge delivering water vapor. It's a molecular form of humidification. It works quite well. Uh but it's a little more on the pricey side.

[00:02:48]And the Optiflow device from Fisher & Paykel, since most of us have the bubble CPAP, you have the same circuit you can use by slight modification. So, you're not going to spend on the circuit if you're switching between bubble CPAP and uh Optiflow. So, most of us tend to prefer to use that.

[00:03:04]You have seven sizes of the nasal cannula and you have to choose appropriate size which has a right leak.

[00:03:10]And the way you fix it also makes sure there is no trauma.

[00:03:13]So, we have the blender, the humidifier, and the circuit including the soft nasal cannula of the appropriate size.

[00:03:20]This is a Vapotherm device. I don't know if any of you use it. So, it's quite simple. The water vapor cartridge is inside here and the blender is kind of built in.

[00:03:29]And obviously, the gas flow is connected and same as you connect the ventilator air and oxygen connections.

[00:03:35]Uh it gives alarms when the appropriate level is not met.

[00:03:41]So, there are many studies coming up in the recent years comparing CPAP and high flow. So, based on these studies, we know that high flow is comparable to CPAP when used at extubation in babies over 28 weeks gestation and over 1.3, 1.4 kilos.

[00:03:56]But uh nasal CPAP and especially NIPPV is better at extubation of the extreme premature babies, those below 28 weeks.

[00:04:04]Even those at 28 weeks or 30 weeks, if you're worried about the work of breathing, I would extubate them to NIPPV rather than start on high flow and risk failure.

[00:04:13]Baby is already intubated, so you can use the same ventilator at that time when you extubate. And once you know baby successfully extubated, you can wean to CPAP on bubble CPAP or high flow.

[00:04:24]And uh as a primary respiratory support, I told you that we need the flexibility of increasing the level uh of say 6 to 7 cm CPAP before you decide on surfactant. Whether you go to seven depends on how cost-effective surfactant is in your setup and affordability. So, if it is readily affordable, I would give it at 6 cm CPAP if it's not maintaining and they have to 30% or 40% as per the size of the baby.

[00:04:49]But if cost is an issue, you can go up to seven. But remember that if you delay the surfactant, you're likely to end up with complications including pneumothorax.

[00:04:58]And when you use as a primary respiratory support, high flow is limited in the ability to go up and you cannot predict how much pressure is given. So, rather don't use high flow as a first mode. Start with CPAP or NIPPV and then come down to high flow once the baby is stable.

[00:05:14]So, there's a good review by Callum Roberts, who's one of the authors of the uh the uh high flow study compared at extubation in extreme preterm babies.

[00:05:26]And uh HIPSTER trial it's called. So, this is a meta-analysis and they looked at uh treatment failure is uh more with high flow and it favors CPAP.

[00:05:37]Intubation needing intubation within 72 hours again it favors CPAP. And complications like pneumothorax, it's comparable between the two. So, obviously, uh we still need further research. I mean, many of us are stuck to not using high flow beyond 8 of the risk of hearing loss and other problems.

[00:05:57]But whether we can increase more than that, we need to study that and in that case, maybe it will be comparable to CPAP. Uh remember that when we look at the HIPSTER trial for example, they used the FiO2 as a criteria for failure. And when we have a 50% leak around the nasal cannula, there is going to be more air drawn in when the baby breathes. The bigger the baby, the more dilution will be there. So, the FiO2 that you see is not actually the FiO2 that the baby gets. It'll be a little lower.

[00:06:25]Uh there is little research comparing Vapotherm and Optiflow for example. And in practical terms, I've used both and they work quite well.

[00:06:33]High flow may be a value as a method of stabilization in the labor room because it's quick to apply. You just need the blended gas.

[00:06:40]And in the labor room as well, we can take the humidifier if you have the option. And when you're intubating the baby, studies have come out showing high flow uh during intubation helps to reduce desaturation.

[00:06:53]There are Cochrane reviews as well on high flow. So, high flow in term babies, it's comparable. In babies with respiratory distress, so we can use it for RDS. We can use it for meconium aspiration or congenital pneumonia or TTN even.

[00:07:07]And in premature babies, similar efficacy in bigger premature babies, but uh in a smaller premature baby less than 28 weeks, we prefer NIPPV as we discussed.

[00:07:17]Uh high flow is associated with less nasal trauma, but uh maybe associated with reduced pneumothorax, but that's not a significant difference.

[00:07:26]So, why do we prefer uh high flow nasal cannula in terms of the nursing staff preference? It's because of the nasal interface being more friendly. But now we have RAM cannula for NIPPV or CPAP, which is equally friendly in terms of the way the baby uh is fitted with it.

[00:07:43]It's comfortable, can be handled for skin-to-skin care quite easily. And uh only disadvantage is that we need to use a higher pressure setting. But that's just to offset. So, it's like the ventilator giving the leak compensation.

[00:07:55]So, it's not really a higher pressure delivered to the baby. It's just that the ability of the ventilator to reach that pressure is there.

[00:08:03]So, uh that's the main reason we preferred high flow because it was easier. But now that we have easier ways to give CPAP and NIPPV, uh if you have the ability, if you have the machine available, preferably use NIPPV in the smaller babies.

[00:08:17]The bigger babies, you can uh optimize the use of machines by using bubble CPAP as well. And remember the circuit can be interchanged. So, once a baby improves and is stable, you can quickly change to high flow. But you need a blender for all of them, so you you have no go but to use a blender as well.

[00:08:36]So, the initial questions, I mean, the baby has respiratory distress with tachypnea or retractions, baby needs pressure. So, don't get used to giving low flow oxygen in the immediate newborn period because the babies need pressure and not just oxygen. Once you start the pressure, maybe you need a little FiO2, but if your FiO2 is high, you need to increase the pressure or escalate the support. And delaying the start of pressure is going to uh lead to a worsening of the baby's condition. So, start early with high flow or CPAP and don't delay. And don't consider low flow in the immediate newborn period for the same reason.

[00:09:10]If the baby is suitable for NIV, start on CPAP. I said 5 to 7 cm max.

[00:09:15]And early surfactant by LISA or INSURE, you can use high flow or maintain the CPAP during this as well.

[00:09:22]And in the acute phase of RDS as the disease is evolving with the risk of worsening, in which case you may need higher pressures, we prefer CPAP or NIPPV rather than high flow.