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
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.
||< 6 mL/kg
||> 6 ml/kg
|Grade 3 or 4
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?
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.
Intubation is not an easy skill to maintain with the declining opportunities that exist as we move more and more to supporting neonates with CPAP. In the tertiary centres this is true and even more so in rural centres or non academic sites where the number of deliveries are lower and the number of infants born before 37 weeks gestational age even smaller. If you are a practitioner working in such a centre you may relate to the following scenario. A woman comes in unexpectedly at 33 weeks gestational age and is in active labour. She is assessed and found to be 8 cm and is too far along to transport. The provider calls for support but there will be an estimated two hours for a team to arrive to retrieve the infant who is about to be born. The baby is born 30 minutes later and develops significant respiratory distress. There is a t-piece resuscitator available but despite application the baby needs 40% oxygen and continues to work hard to breathe. A call is made to the transport team who asks if you can intubate and give surfactant. Your reply is that you haven’t intubated in quite some time and aren’t sure if you can do it. It is in this scenario that the following strategy might be helpful.
Surfactant Administration Through and Laryngeal Mask Airway (LMA)
Use of an LMA has been taught for years in NRP now as a good choice to support ventilation when one can’t intubate. The device is easy enough to insert and given that it has a central lumen through which gases are exchanged it provides a means by which surfactant could be instilled through a catheter placed down the lumen of the device. Roberts KD et al published an interesting unmasked but randomized study on this topic Laryngeal Mask Airway for Surfactant Administration in Neonates: A Randomized, Controlled Trial. Due to size limitations (ELBWs are too small to use this in using LMA devices) the eligible infants included those from 28 0/7 to 35 6/7 weeks and ≥1250 g. The infants needed to all be on CPAP +6 first and then fell into one of two treatment groups based on the following inclusion criteria: age ≤36 hours,
(FiO2) 0.30-0.40 for ≥30 minutes (target SpO2 88% and 92%), and chest radiograph and clinical presentation consistent with RDS.
Exclusion criteria included prior mechanical ventilation or surfactant administration, major congenital anomalies, abnormality of the airway, respiratory distress because of an etiology other than RDS, or an Apgar score <5 at 5 minutes of age.
Procedure & Primary Outcome
After the LMA was placed a y-connector was attached to the proximal end. On one side a CO2 detector was placed and then a bag valve mask in order to provide manual breaths and confirm placement over the airway. The other port was used to advance a catheter and administer curosurf in 2 mL aliquots. Prior to and then at the conclusion of the procedure the stomach contents were aspirated and the amount of surfactant determined to provide an estimate of how much surfactant was delivered to the lungs. The primary outcome was treatment failure necessitating intubation and mechanical ventilation in the first 7 days of life. Treatment failure was defined upfront and required 2 of the following: (1) FiO2 >0.40 for >30
minutes (to maintain SpO2 between 88% and 92%), (2) PCO2 >65 mmHg on arterial or capillary blood gas or >70 on venous blood gas, or (3) pH <7.22 or 1 of the following: (1) recurrent or severe apnea, (2) hemodynamic instability requiring pressors, (3) repeat surfactant dose, or (4) deemed necessary by medical provider.
Did it work?
It actually did. Of the 103 patients enrolled (50 LMA and 53 control) 38% required intubation in the LMA group vs 64% in the control arm. The authors did not reach their desired enrollment based on their power calculation but that is ok given that they found a difference. What is really interesting is that they found a difference in the clinical end point despite many infants clearly not receiving a full dose of surfactant as measured by gastric aspirate. Roughly 25% of the infants were found to have not received any surfactant, 20% had >50% of the dose in the stomach and the other 50+% had < 10% of the dose in the stomach meaning that the majority was in fact deposited in the lungs. I suppose it shouldn’t come as a surprise that among the secondary outcomes the duration length of mechanical ventilation did not differ between two groups which I presume occurred due to the babies needing intubation being similar. If you needed it you needed it so to speak. Further evidence though of the effectiveness of the therapy was that the average FiO2 30 minutes after being treated was significantly lower in the group with the LMA treatment 27 vs 35%. What would have been interesting to see is if you excluded the patients who received little or no surfactant, how did the ones treated with intratracheal deposition of the dose fare? One nice thing to see though was the lack of harm as evidenced by no increased rate of pneumothorax, prolonged ventilation or higher oxygen.
Should we do this routinely?
There was a 26% reduction in intubations in te LMA group which if we take this as the absolute risk reduction means that for every 4 patients treated with an LMA surfactant approach, one patient will avoid intubation. That is pretty darn good! If we also take into account that in the real world, if we thought that little of the surfactant entered the lung we would reapply the mask and try the treatment again. Even if we didn’t do it right away we might do it hours later.
In a tertiary care centre, this approach may not be needed as a primary method. If you fail to intubate though for surfactant this might well be a safe approach to try while waiting for a more definitive airway. Importantly this won’t help you below 28 weeks or 1250g as the LMA is too small but with smaller LMAs might this be possible. Stay tuned as I suspect this is not the last we will hear of this strategy!
This post rings in another new video to add to the series on the All Things Neonatal YouTube channel. I hope that you have gotten something out of the ones posted so far and that this adds something further to your approach to neonatal care.
The Golden Hour Revisited
In the last post to the video selections entitled A Golden Opportunity For Your NICU Team! the main thrust of the video was on the use of the Golden Hour approach to starting a baby on CPAP. Having a standardized checklist based approach to providing care to high risk newborns improves team functioning for sure. What do you do though when you need to hand off a patient to another team? Depending on where you work this may not be an issue if the team performing the resuscitation is the team providing the care for the patient in the NICU. Perhaps you work in a centre similar to our own where the team performing resuscitation is not the same as the one who will ultimately admit the patient. You may also be in a location where there are no babies born on site but rather all patients are transferred in so in each case the patient is new to everyone on the receiving team. How do you ensure that a complete hand over is done.
Out with the old and in with the new!
By no means do I want to imply that it is not possible to transfer information outside of the way that we demonstrate in this video. What I do believe though is that with telehealth being available in more and more settings or without a formal support for the same, the use of smartphones make video conferencing a reality for almost everyone. In most centres handovers have followed the practice of like communicating with like. Nurses give report to nurses, respiratory therapists to each other and MDs to MDs. What if there was another way though? In the video below we demonstrate another approach. Would it work for your team?
As you can tell I am a big fan of simulation in helping to create high functioning teams! More of these videos can be accessed on my Youtube channel at
All Things Neonatal YouTube
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Lastly a big thank you to NS, RH and GS without whom none of this would have been possible!
When you mention electronic medical records to some physicians you get mixed responses. Some love them and some…well not so much. These tech heavy platforms promise to streamline workflows and reduce error with drop down menus, some degree of artificial intelligence in providing warnings when you stray too far from acceptable practice but for some who are not so tech savvy they are more of a pain. I have to admit I am in the camp of believing they are a good thing for patient care as I work in one centre with expanded EMR services and one without and I do find a number of benefits to working with a more robust EMR platform but I respect that not all do.
The cell phone on the other hand is everywhere and even the most tech fearful often carry one including most of the parents we care for. What caught my eye this month was the article by Globus O The use of short message services (SMS) to provide medical updating to parents in the NICU in which an EMR system is described that sends parents a text message at a pre-specified time regarding their infants condition. I had a visceral reaction at first thought thinking “would I want my cell phone number sent to families?”, “how much time out of the day would all of this take?” and to be a little old fashioned “can’t we just talk on the phone?”. I am sure there are many other questions that others would have as well. Having said that as I read through the paper I warmed to the concept and by the end questioned whether we could do the same!
It turns out the SMS message comes from the EMR and not the personal cell phone of the bedside nurse and is sent out at 9 AM each day. Each nurse requires only 30 seconds of their day to populate a few questions during the night shift and then the information goes out to the parents.
“The text message includes one-sentence prefaces and conclusions and provides updated information that includes the location of the infant’s crib (room and position), the infant’s current weight and whether medical procedures, such as head ultrasound, cardiac echocardiogram or eye examination, were performed. Information regarding acute events or deterioration of the infant’s medical condition are not included in the SMS, but are delivered personally to the parents in real time.”
This last sentence is important. The SMS service will not notify the family that their infant is receiving chest compressions but is there to give them “updates”. The sceptics out there will likely comment that this should be the job of both nursing and medicine to regularly update the families but thinking about it, how many parents are not there everyday and when they are out of sight how many physicians regularly call them to provide them updates? No doubt there are some but I would think they are not in the majority.
But is it effective?
The measurement in this case was through surveys of nursing and families both pre-implementation and afterwards. Provided in the table below are the scores (means +/- SD) in the pre and post implementation phases of the program.
||Post SMSi N=87
|The physician was available when needed
|The physician was patient in answering my questions
|I felt comfortable approaching the physicians
|I felt comfortable approaching the nurses
|I regularly received information from the physicians regarding my infant’s medical status
These are some pretty powerful outcomes. The use of what many consider an impersonal form of communication (how many times have I looked at people texting furiously and thought JUST PICK UP THE PHONE!) actually appears to have improved the approachability of the staff in the unit and facilitated information transfer more easily.
One other important finding was that when surveyed pre-intervention staff were somewhat sceptical that this would help and moreover were concerned that it would interfere too much with work flow in the day. Evaluations afterwards did not support these fears and many felt it was an improvement. In the end the total time spent on this by nursing was estimated to be no more than 30 seconds of each day! From the parent’s standpoint they certainly saw this as an improvement.
At least in our centre we are moving slowly but steadily towards a fully functioning EMR. Will we have this capability in the software that we use? After reading this I hope so. I can see how receiving a daily morning message would prime the family to interact with staff on rounds. The added benefit is that by knowing that the information would be ready at 9 AM, families could be present with questions already formulated in their minds. How often do we encourage families to be on rounds and have them listen to a tremendous amount of information and then turn to them with the standard “any questions?”. While I am sure many of us try and explain matters in lay terms, giving parents a change to mull over the issues first could well enhance the interaction they have with our team in a meaningful way.
Time to look into whether this is possible…