HFOV + VG in ELBW

[RMM]

Just wondering what experience fellow practitioners have when oscillating ELBW babies with the Drager VN500 and using VG?
 

We have a 425g baby who is being gently oscillated with Hz 15 , VG = 0.5ml (lowest setting available), set amplitude of 10 and only requiring amplitudes of 5-7 to achieve volumes. Running with pCO2 in low 40’s/high 30’s. Still in 30% oxygen with MAP of 10.

Not keen to extubate quite yet. Has anyone used Hz >15? Any thoughts would be greatly appreciated.

[lukaswisgrill]

Hi,

your story and setting sounds quite good. We don't use the Drager, but we use the Accutronic "Fabian" with HFOV + VG and it works great - especially for ELBWI. To me personally, the settings are quite low and I would attempt to extubate the baby (but I don't know any other facts - just from your respirator settings). We never go above 15 Hz in our center (as far as I know), so I cannot help you with that answer .... but I would interpret it as a sign - if you thinking of more than 15 Hz --> extubate ;-)

But it is an very interesting question, maybe we get a good answer and learn something today!

[livesynapse]

According to Dr. Sanchez-Luna's papers, if you use HFOV and VG, you can lower the frequency in order to avoid hypocapnia. It works in the opposite way as HFOV without VG. Here's the reference: Am J Perinatol 2018;35:545–548.

[Tanya Clarke]

https://www.draeger.com/Library/Content/hfov-bk-9102693-en.pdf
 

booklet from Prof Jane Pillow will answer all your questions on HFOV with VG in Babylog VN500

[r.dippenaar]

Evening we have both devices the Fabian VG is great but recently we were alerted to a software update for VG so little cautious on our sub 500 grm babies at present  . The Draeger similar positive experience no issues. In our experience we would attempt extubating the infant provided no haemodynamically significant pda or major IVH. But achieving the MAP of 10 is often difficult with non invasive nasal Cpap even with biphasic/duopap option . So we have opted for non invasive nasal osscilation using Ramanathans RAM nasal cannula fits directly onto the vent y connector with same MAP or 1 higher  hz 10 amp 20 as a starting point although they seem fo tolerate 1:2 ratio better . Highly efficient system can very easily cause hypocapnia so we use transcutaneous co2 to monitor . Fi02 only minimally increases in most infants and the followup chest xrays inevitably deteriorate out of proportion to the infants clinical picture but clears after a few days.  The infant in naturally nursed prone and the head flexed or extended until a good neutral position and a good chest wiggle is observed . The nursing staff love the system and it allows you to bridge to a point where the infant either transitions to nasal CPAP or the nasal high flow vapourtherm systems . Just our humble experience and approach for micro 

Good luck 

Ricky Dippenaar 

[nazirburki]

Glad to hear about RAM CANNULA, some of our neonatologist are not convinced that RC can be used for NIPPV or if it is effective. I can report 2 premies less than 500g , where we were struggling with interface to extubate to. Ram Cannula worked perfectly both for Ventilation and oxygenation ( with a 5 to 10% more fio2 compared to when intubated). 2nd HFO is considered an escalation of ventilatory support ( it is true but once started, KEPP on HFO, till you extubate) but the oppsoite happens most of the time, and we as clinicians consider back to CV a weaning or improvement. this needs to be changed

[RMM]

Hi All

Thanks very much for all of those responses - it is interesting to see that we are not the only unit struggling with this phenomenon as we extend the limits of both gestational age and weight! Prof Jane Pillow's book on HFOV is certainly a well-read resource.

Just a few  further comments:

- we would normally extubate a baby from HFOV at those low settings rather than de-escalating or weaning to CMV first - the issue we have sometimes is that on initial echo (usually done in the 1st 12-24hrs of life) there is often persistent transitional circulation (PPHN if you will) with these severely growth restricted babies (in our experience) and so closing the PDA in this context makes us very nervous. We have had a few severely growth restricted babies (<450g) who have had catastrophic pulmonary hypertensive crises in the first week of life and we have not been able to get them back from this. Ideally once the pulmonary pressures drop and if the DA is still patent then we would close it with paracetamol and then look to extubate these babies from HFOV

- the 2nd problem we then have when are considering extubation, is the size of these infants nares and mid-face don't allow appropriate fitment of our NIPPV or BCPAP interface. We use the F&P circuit and bubble CPAP device with either the binasal prongs or masks (see images below); despite these coming in several sizes we always seem to have issues with precise fitment; our nursing staff are exceptionally vigilant in alternating the prongs and the mask when cares are done in order to avoid sustained pressure to the nasal septum of nasal bridge and this seems to work well; we still have issues intermittently with nasal septal injury because of incorrectly sized masks that tend ride up into the septum.

The RAM cannula and nHFOV sounds like a terrific option - thank you for sharing that! Some of our Neonatologists have made murmurings about using this in the past. When looking at the RAM interface it does seem unlikely that this device would be able to provide enough MAP to these babies but the technical details on NeoTECH website is certainly reassuring. It is also helpful to hear that other units have had good experiences with the RAM cannula and nHFOV in these extremely growth restricted babies. I suspect it would take quite a bit of education with our nursing staff for them to trust this interface to provide adequate support but there is literature that supports it's use and therefore something we should definitely consider.

An update on our case above:

This little one did have quite significant transitional circulation/ PPHN and a large PDA on initial CPU echocardiography so we just sat tight and waited it out initially. We have recently started using tcCO2 monitoring again and that was very helpful to keep an eye CO2 trends in this baby given the exceptionally low HFOV settings he was on. Once the pulmonary pressures had dropped, paracetamol was given to treat the PDA. He reached full feeds by D7 and had a normal head USS on D5. We have continued his gentle HFOV settings as above and his oxygen requirement has been stable ~30%. He is now D13 of life and weighs ~600g so we are going to electively extubate him from HFOV onto NIPPV despite the interface not being 100% compatible size wise but we feel this is the window! A lot learnt from this case for us for sure!

As side note - we had a 320g, 25/40 deliver last week who is also on HFOV + VG via the Drager VN500. A technical challenge to because of his size but he has a significant oxygen requirement and ongoing issues with CO2 clearance after a pulmonary haemorrhage on D2 of life so is needing a bit more in the way of support in comparison to the above-mentioned case. Fingers crossed!

Thanks again for all the comments.

I hope you all have a great Christmas and here's to a much better 2021!! 

Best wishes from Down Under

Richard