What approaches are in use around the world for the ventilation of CDH (especially pre-operative on or off ECMO)?  Many guidelines continue to list PIP limits based on earlier studies of 'gentle ventilation' improving survival, but these studies were done before significant advances in microprocessors enabled accurate volume targeted ventilation.  Given what we know about the importance of volume-trauma as opposed to baro-trauma, is anyone volume ventilating pre-operative CDH and permitting higher peak pressures?

We have had  good outcomes utilizing conventional ventilation A/C + Vg  set at 3 -3.5 ml/kg originally with 8000 + now the Vn  , peep starting at 7-8 , rate 50 , we have an early exit to High frequency JET ventilation ( Bunnell Jet  Life Pulse  USA)   jet rate set at 240 bpm  peep 8 or greater ,on time of o.o2. the jet allows for the use of  optimal chest expansion (higher peeps) but lower MAP than required with Hfov , the Bunnell   has only active inspiration , expiration is passive , the lower jet rate allows for I:E rations 1 to 12 , passive expiration allows the lower MAP  and allows for optimal ventilation in non homogenic lung diseases We do not use HFOV. I believe one of our students presented an abstract on our experience and more lasts year at the meeting in England . We also utilize ino  if required.  We are not an Ecmo center.   Winnipeg Manitoba Canada  

23 hours ago, jminski said:

We have had  good outcomes utilizing conventional ventilation A/C + Vg  set at 3 -3.5 ml/kg originally with 8000 + now the Vn

Many thanks.  Where do you set your PIP alarms?  More generally, how concerned are you about peak pressures and 'barotrauma'?

 

We also start on AC-VG. We bring the ventilator into the delivery room and once intubated, get them on to volume ventilation and avoid as much t-piece or bag ventilation as possible. Initial settings are PEEP 5-6, 4-5mL/kg tidal volume, back up rate of 40, and iTime 0.3. We set PIP max at 3-5 cm H2O above the working PIP on the ventilator for the set tidal volume. If PIP to achieve these volumes is going above 28 or we are unable to make our target CO2 (50-70), we switch to HFOV. We are probably pretty quick to go to ECMO if needed, but we also have a fetal center doing fetal endoscopic tracheal occlusion (FETO) on severe cases and probably get a more severe population as a whole. Texas Childrens, Houston, Texas, U.S.

"We also start on AC-VG. We bring the ventilator into the delivery room and once intubated, get them on to volume ventilation and avoid as much t-piece or bag ventilation as possible. Initial settings are PEEP 5-6, 4-5mL/kg tidal volume, back up rate of 40, and iTime 0.3"

Nathan's approach above is a lot more evidence-based than the earlier post from Winnipeg. There is good evidence that relatively low PEEP should be used to avoid over-expansion of the hypoplastic lungs, which contributes to PPHN (Guevorkian, et al, J Pediatrics 2018). The results of the VICI trial also strongly indicate that high distending pressure is detrimental. For some reason (maybe someone will comment on the rationale, I can't think of one) the investigators chose to use an aggressive lung recruitment strategy with HFOV and a gentle, low PEEP strategy with conventional ventilation. The outcomes favored conventional ventilation over HFOV, but that is because the WRONG strategy was used with HFOV, IMHO, not because HFOV is inherently bad for CDH. 

We looked at the VT needed to keep a normal PCO2 in CHD and found it to be 4.5 ml/kg. These were data from fairly long ago, when we targeted normal PCO2 in low 40s (Sharma, et al, Am J Perinatol. 2015). 4ml/kg is probably appropriate when aiming for mild permissive hypercapnia. Babies with CDH have the same rate of metabolic CO2 production as any other baby that size, so they need roughly the same alveolar minute ventilation, even if their lungs are small. 3ml/kg would be unlikely to work, since that is the volume of anatomical and instrumental dead space. But I know people who use 3ml/kg because you have a large ETT leak and are not using leak compensation, so that the real VT is around 4ml/kg, but they don’t realize it.

Thanks,

Martin Keszler MD

Professor of Pediatrics, 

Brown University

Dear Martin,

 

I am curious what saturations to you target in the delivery room and first 2 hours Martin

Do you start with an FIO2 of 100

 

My assumption  if you use AC is you want the baby to trigger. Do yo use any sedation and have you stopped using routine paralysis?

 

 

Alok

On 10/29/2018 at 6:00 PM, Martin.Keszler said:

you have a large ETT leak and are not using leak compensation

Are you relying solely on leak compensation from your vent or are you using cuffed tubes to manage the leak itself?  

I like the european consensus in management of CDH really it is very nice and helpful

#### also there is new modality which we are trying to use it which is applying VG with HFOV(1-3 ml/kg)

 

CDH EURO Consortium Consensus.pdf

@spartacus007: 

Sorry for slow response. Yes we would use AC and avoid heavy sedation. Only use paralysis if despite good NG tube placement we are unable to keep gut decompressed, meaning we use it rarely. Evidence-free zone, for the most part, but muscle relaxation has many downsides and I am a believer in making the baby breathe as much as they can, which minimizes intrathoracic pressure and adverse hemodynamic consequences of PPV.

As for SPO2 target, the goal is NOT 100%. Gentle support with minimal PIP needed to get the heart rate up and SPO2 into the low 90s. Generally start with FiO2 around 0.6 and wean if SPO2 is >92-93%.

@bimalc : We do not use cuffed tubes, though it would be appropriate if you did not have a ventilator that has excellent leak compensation capability, like the Draeger VN 500, which can accurately compensate for leak of up to 60-70%. If you have a leak anywhere near that large, the baby need a larger tube.

@tarek: I love the HFOV + VG. It works very nicely, but in the USA, the HFOV option is not yet approved by the FDA, so I was only able to use it in the context of our preeemie study that will hopefully lead to approval. Given that CO2 removal with HFOV is proportional to F x VT squared, the ability to maintain a constant VT in the face of changing lung compliance is particularly attractive. In my 27 babies we used it on it worked beautifully!

Cheers,
Martin

There is confusion here about set Vt and dead space volume. Do babies on 4-5 ml/kg Vt need an additional 0.8 ml added to that value to account for the flow sensor? Or do the varying Vt targets for different underlying pathologies already include the fixed dead space (ex flow sensor dead space of ~0.8 ml on Draeger babylog relatively more impact on ELBW babies, thus target 5-6 ml/kg)? Or is there a weight-based dead space calculation?

or

Which of these would be right for a 400g baby?

0.5 kg x 6 ml/kg = Vt 3 ml

or 

(0.5 kg x 6 ml/kg) + 0.8 ml = Vt 3.8 ml

or

something else?

0.5 kg x (6 ml/kg + 0.5 ml/kg)  = Vt 3.25 ml