I took over the care of a 24 weeker who developed PIE at about 5 days of life. Baby was doing well on conventional vent (volume-targeted ventilation), when at day 3 their oxygenation and ventilation began worsening. By day 5, PiPs were in the high 20s/low 30s. By day 6, the decision was made to change to HFOV. 

Our attempts to wean MAP while keeping SpO2 >88% were unsuccessful. We were able to get the MAP from 18 down to 14, but attempts to wean lower resulted in worsening oxygenation. 

At DOL 7, I made the decision that unless we could get the PIE to resolve, we were likely going to lose the baby, so I changed the strategy. Weaning the MAP became the primary concern at the expense of FiO2 and SpO2. I am accepting SpO2 in the 80s and 100% FiO2. I am allowing hypercarbia as long as the pH is >= 7.25 and pCO2 is < 70. This has required a higher amplitude and lower Hz than I would like, but it seems to be working. 

Do any of you have specific experience in treating PIE with HFOV? If so, what worked and what didn't work? How did you manage the Hz/frequency?

I will give an update later today. 

Over the past 3 hours, I have slowly weaned the MAP from 11 to 9. FiO2 has remained 80-90% while SpO2 has been 88 - 91%. Blood gas prior to weaning was 7.31/42/41/21/-5 and the CXR still looked hyperexpanded at a MAP of 11.

Most recent gas on MAP 9, Amplitude of 38 and Hz of 9.5 was 7.13/69.6/45/23/-6, 90% FiO2 and 90% SpO2. I dropped the Hz by 0.5 but left all other parameters as they were. Although the base deficit is slowly worsening, he has brisk capillary refill, is urinating briskly, and is maintaining MBPs >32 mmHg without vasopressors or inotropes, thus his delivery of oxygen has not been severely compromised by accepting lower SpO2. 

Great topic! During my years at the Karolinska NICU, we used HFOV a lot (these days, the SensorMedics was *the* machine), much thanks to my mentor Baldvin Jonsson who was trained by @Martin.Keszler. 

This "low-volume strategy" with HFOV is still the prevailing strategy with airleaks in Stockholm, as far as I know from my level2+ context these days, i.e. reducing pressure as much as possible at the expense of increased FiO2.

Sounds this infant manages well!

 

We had a very similar 24w last year, he was in HFO for several weeks and there are some reports of using either HFJV (which we don’t have in Chile) or HFO with low rates. We used HFO+VG with a target of SpO2 of >80% (or at least to achieve a normal brain rSO2) and pCO2 65-70, using rates of 5-6 Hz to increase expiratory time. He needed dexamethasone and then hydrocortisone for weaning, diuretics for several weeks, and was discharged at 41-42 weeks of CGA with O2 0,1 lpm. Really bad chest xray though, some big bullae.

You are in the right way. HFO fq 5-6 Hz, Amp as high as you see Vibration. Lower MAP as you did, but try do use less, Oxygen max 70%. Permissiv hypercabnia ok. Lay your patient on his dummy. Both sided PIE,  equal? If not: best side up. 

I just started using the jet and I am not impressed by the amount of parameters used and modified

I previously managed those patients the same way you did, great job

A problem that most units would see when looking after babies at the extremes of viability. We have used HFOV + VG (VG 1-3mL/kg) to manage these babies and generally don't have to reduce the frequency below 10Hz. Using "Sigh Breathes" can also be useful in these babies but like another poster suggested, using an early DART course may be useful as well as treating other underlying co-morbidities e.g. anaemia, VAP, PDA etc.

 

This is taken from Prof Jane Pillow's manual on the use of HFOV that is published by Drager. Just thought it would be worth sharing. 

Let us know how you get on with this wee little one!

Richard

 

Thank you everyone for your input. In spite of continuing to lower the MAP, the CXR remains hyperexpanded. Base deficit slowly worsened throughout the day, although BP remained acceptable. The Hct is stable at 45%. I gave 20/kg of isotonic bicarbonate last night for a base deficit of -10, and the pH and base deficit improved. 

Awaiting another CXR this morning, if it still looks hyperexpanded, I will focus more on decreasing Hz. There seems to be some disagreement in what limited literature I can find (mostly opinions) as to whether a Hz of 12-15 or Hz of 6-9 is more beneficial. Anecdotal only, but this baby seems to be responding better to the low Hz strategy. I will get a bit more aggressive about lowering Hz today, then maybe I can start weaning the amplitude as I speculate it may be the culprit of hyperexpansion.

I have used the HFJV in the past to manage PIE, with good results, certainly a much more rapid response than the current case I am managing. However, at my current facility, we do not have a HFJV. Also, we are using the SensorMedics HFOV, which to my knowledge, does not have the ability to do HFOV+VG. 

As to repositioning the baby, we tried this earlier this week with abysmal results. Repositioning on the SensorMedics HFOV is very difficult. 

I will give an update in an hour or two.

I know the Sensormedics well, it is a great machine and with few buttons  I am not aware of any VG addon. The hyperinflation may be related to the PIE as such, maybe you could even reduce the CDP slightly more. My experience with decreasing the Hz is mostly related to management of CO2-retention, but I would def try to lower Hz in this case. Just keep an eye on CO2-levels so you don't end up in hypocarbia.

We got the Hz down to 6, but our first attempt to wean the amplitude resulted in a pretty significant respiratory acidosis.

What is really strange is that in spite of weaning the MAP from its original 14 to now 8, the hyperexapnsion by CXR is getting worse. I speculate that the air leak is not healing at all, and we essentially have thousands of little tension pneumothoraces surrounding what little areas of gas exchange the baby has; I wouldn't really call them alveoli at 24 weeks. 

Awaiting an echo now to assess shunting and see if an argument can be made to increase contractility with milrinone.