Gentle ventilation must start from birth

Gentle ventilation must start from birth

The lungs of a preterm infant are so fragile that over time pressure limited time cycled ventilation has given way to volume guaranteed (VG) or at least measured breaths.  It really hasn’t been that long that this has been in vogue.  As a fellow I moved from one program that only used VG modes to another program where VG may as well have been a four letter word.  With time and some good research it has become evident that minimizing excessive tidal volumes by controlling the volume provided with each breath is the way to go in the NICU and was the subject of a Cochrane review entitled Volume-targeted versus pressure-limited ventilation in neonates. In case you missed it, the highlights are that neonates ventilated with volume instead of pressure limits had reduced rates of:

death or BPD

pneumothoraces

hypocarbia

severe cranial ultrasound pathologies

duration of ventilation

These are all outcomes that matter greatly but the question is would starting this approach earlier make an even bigger difference?

Volume Ventilation In The Delivery Room

I was taught a long time ago that overdistending the lungs of an ELBW in the first few breaths can make the difference between a baby who extubates quickly and one who goes onto have terribly scarred lungs and a reliance on ventilation for a protracted period of time.  How do we ventilate the newborn though?  Some use a self inflating bag, others an anaesthesia bag and still others a t-piece resuscitator.  In each case one either attempts to deliver a PIP using the sensitivity of their hand or sets a pressure as with a t-piece resuscitator and hopes that the delivered volume gets into the lungs.   The question though is how much are we giving when we do that?

High or Low – Does it make a difference to rates of IVH?

One of my favourite groups in Edmonton recently published the following paper; Impact of delivered tidal volume on the occurrence of intraventricular haemorrhage in preterm infants during positive pressure ventilation in the delivery room. This prospective study used a t-piece resuscitator with a flow sensor attached that was able to calculate the volume of each breath delivered over 120 seconds to babies born at < 29 weeks who required support for that duration.  In each case the pressure was set at 24 for  PIP and +6 for PEEP.  The question on the authors’ minds was that all other things being equal (baseline characteristics of the two groups were the same) would 41 infants given a mean volume < 6 ml/kg have less IVH compared to the larger group of 124 with a mean Vt of > 6 ml/kg.  Before getting into the results, the median numbers for each group were 5.3 and 8.7 mL/kg respectively for the low and high groups.  The higher group having a median quite different from the mean suggests the distribution of values was skewed to the left meaning a greater number of babies were ventilated with lower values but that some ones with higher values dragged the median up.

Results

IVH < 6 mL/kg > 6 ml/kg p
1 5% 48%
2 2% 13%
3 0 5%
4 5% 35%
Grade 3 or 4 6% 27% 0.01
All grades 12% 51% 0.008

Let’s be fair though and acknowledge that much can happen from the time a patient leaves the delivery room until the time of their head ultrasounds.  The authors did a reasonable job though of accounting for these things by looking at such variables as NIRS cerebral oxygenation readings, blood pressures, rates of prophylactic indomethacin use all of which might be expected to influence rates of IVH and none were different.  The message regardless from this study is that excessive tidal volume delivered after delivery is likely harmful.  The problem now is what to do about it?

The Quandary

Unless I am mistaken, there isn’t a volume regulated bag-mask device that we can turn to for control of delivered tidal volume.  Given that all the babies were treated the same with the same pressures I have to believe that the babies with stiffer lungs responded less in terms of lung expansion so in essence the worse the baby, the better they did in the long run at least from the IVH standpoint.  The babies with the more compliant lungs may have suffered from being “too good”.  Getting a good seal and providing good breathes with a BVM takes a lot of skill and practice.  This is why the t-piece resuscitator grew in popularity so quickly.  If you can turn a couple of dials and place it over the mouth and nose of a baby you can ventilate a newborn.  The challenge though is that there is no feedback.  How much volume are you giving when you start with the same settings for everyone?  What may seem easy is actually quite complicated in terms of knowing what we are truly delivering to the patient.  I would put to you that someone far smarter than I needs to develop a commercially available BVM device with real-time feedback on delivered volume rather than pressure.  Being able to adjust our pressure settings whether they be manual or set on a device is needed and fast!

Perhaps someone reading this might whisper in the ear of an engineer somewhere and figure out how to do this in a device that is low enough cost for everyday use.

Informed Refusal at 22 weeks

Informed Refusal at 22 weeks

While we draw the line at 22 5/7 weeks for offering active resuscitation where I work, what does one do when the family requests resuscitation prior to that point.  While I am a clear fan of social media, one consequence of having such widely available information at our fingertips is that families may already know before you come to speak with them that were they only to have been born in another place like Montreal, the cutoff would have been lower.  When faced with such demands what does one do?  Well, in the case of my own experience it was to give in to the demands of the parents.  While I certainly discourage such heroic attempts, what is one to say when the family having received your opinion states “I want everything done”.  Informed consent is a tricky one in that if you approach a family for informed consent and they refuse to accept your desired direction of care where does that leave you?  It leaves you with informed refusal and if we are being fair to our families we have to accept that informed refusal is just as important as informed consent.

Nothing New?

The truth is informed refusal has been recognized as being critically important to decisions in patient care for many years.  Previous papers on the subject include a nice review by Ridley DT, Informed consent, informed refusal, informed choice–what is it that makes a patient’s medical treatment decisions informed?  What this really comes down to is a patient’s right to personal autonomy and self determination.  Does a parent in this case have the right to do what they want even in the face of dismal odds?  Furthermore where are we placing the importance of values?  Is it physician or patient centric?  In the physician centric world, after we impart our experience and wisdom we expect the patient to generally follow through with what we are steering them towards in cases such as this.  Informed consent of course is meant to be free of coercion but let’s face it, when we truly believe something is fairly futile are we honestly playing an impartial role or using our tone, body language and choice of words to direct families down the path that fits with our own beliefs and values?  I would offer that in most cases when we seek informed consent what we are really doing is seeking to pass along the justification for what we are wanting to do and then moving forward once obtained.

What do we do though when after hearing the pros and cons the family still opts to move forward and worse yet is in disagreement with our preferred plan.  Well there you arrive at informed refusal.  If after hearing our best transfer of information the family still wants to proceed what does one do?  As a physician if I believe something is completely futile and I find myself in this position then I am truly at fault.  Seeking informed consent in this situation was completely inappropriate.  One should have simply said there is nothing that can be done.

The Montreal Example

Getting back to the example that started this piece, if a family knows that there are places in Canada (or let’s be honest, if I know there are survivors in Canada at 22 weeks) that resuscitate and have survivors then it isn’t really futile is it.  I know many of you would say “but the odds are so stacked against the baby” and “they don’t know what they are getting themselves into” but what does one say in this circumstance when despite your best attempts the family still wants to resuscitate?

Therein lies the challenge.  If we approach this as an opportunity for informed consent we need to accept that we may find ourselves face to face with “informed refusal”.  Now I need to be careful here.  I am not advocating a wide open optimistic approach to resuscitation at 22 weeks.  What I am suggesting though is that if you find yourself coming into a unit somewhere in the next few months and find yourselves looking at a 22 week infant don’t jump to conclusions!  Did the family despite all the warnings want this?  Don’t leap to the thought that the Neonatologist is pushing for this but rather it may indeed be a case of a family advocating for their child against all odds.  It may not be something that we agree with in many cases but are we thinking from the perspective of the family or our own value system?