For almost a decade now confirmation of intubation is to be done using detection of exhaled CO2. The 7th Edition of NRP has the following to say about confirmation of ETT placement “The primary methods of confirming endotracheal tube placement within the trachea are detecting exhaled CO2 and a rapidly rising heart rate.” They further acknowledge that there are two options for determining the presence of CO2 “There are 2 types of CO2 detectors available. Colorimetric devices change color in the presence of CO2. These are the most commonly used devices in the delivery room. Capnographs are electronic monitors that display the CO2 concentration with each breath.” The NRP program stops short of recommending one versus the other. I don’t have access to the costs of the colorimetric detectors but I would imagine they are MUCH cheaper than the equipment and sensors required to perform capnography using the NM3 monitor as an example. The real question though is if capnography is truly better and might change practice and create a safer resuscitation, is it the way to go?
Fast but not fast enough?
So we have a direct comparison to look at. Hunt KA st al published Detection of exhaled carbon dioxide following intubation during resuscitation at delivery this month. They started from the standpoint of knowing from the manufacturer of the Pedicap that it takes a partial pressure of CO2 of 4 mm Hg to begin seeing a colour change from purple to yellow but only when the CO2 reaches 15 mm Hg do you see a consistent colour change with that device. The capnograph from the NM3 monitor on the other hand is quantitative so is able to accurately display when those two thresholds are reached. This allowed the group to compare how long it took to see the first colour change compared to any detection of CO2 and then at the 4 and 15 mm Hg levels to see which is the quicker method of detection. It is an interesting question as what would happen if you were in a resuscitation and the person intubates and swears that they are in but there is no colour change for 5, 10 or 15 seconds or longer? At what point do you pull the ETT? Compare that with a quantitative method in which there is CO2 present but it is lower than 4. Would you leave the tube in and use more pressure (either PIP/PEEP or both?)? Before looking at the results, it will not shock you that ANY CO2 should be detected faster than two thresholds but does it make a difference to your resuscitation?
The Head to Head Comparison
The study was done retrospectively for 64 infants with a confirmed intubation using the NM3 monitor and capnography. Notably the centre did not use a colorimetric detector as a comparison group but rather relied on the manufacturers data indicating the 4 and 15 mm Hg thresholds for colour changes. The mean age of patients intubated was 27 weeks with a range of 23 – 34 weeks. The results I believe show something quite interesting and informative.
Median time secs (range)
Earliest CO2 detection
3.7 (0 – 44s)
4 mm Hg
5.3 (0 – 727)
15 mm Hg
8.1 (0 – 727)
I wouldn’t worry too much about a difference of 1.6 seconds to start getting a colour change but it is the range that has me a little worried. The vast majority of the patients demonstrated a level of 4 or 15 mm Hg within 50 seconds although many were found to take 25-50 seconds. When compared to a highest level of 44 seconds in the first detection of CO2 group it leads one to scratch their head. How many times have you been in a resuscitation and with no CO2 change you keep the ETT in past 25 seconds? Looking closer at the patients, there were 12 patients that took more than 30 seconds to reach a threshold of 4 mm Hg. All but one of the patients had a heart rate in between 60-85. Additionally there was an inverse relationship found between gestational age and time to detection. In other words, the smallest of the babies in the study took the longest to establish the threshold of 4 and 15 mm Hg.
Putting it into context?
What this study tells me is that the most fragile of infants may take the longest time to register a colour change using the colorimetric devices. It may well be that these infants take longer to open up their pulmonary vasculature and deliver CO2 to the alveoli. As well these same infants may take longer to open the lung and exhale the CO2. I suppose I worry that when a resuscitation is not going well and an infant at 25 weeks is bradycardic and being given PPV through an ETT without colour change, are they really not intubated? In our own centre we use capnometry in these infants (looks for a wave form of CO2) which may be the best option if you are looking to avoid purchasing equipment for quantitative CO2 measurements. I do worry though that in places where the colorimetric devices are used for all there will be patients who are extubated due to the thought that they in fact have an esophageal intubation when the truth is they just need time to get the CO2 high enough to register a change in colour.
Anyways, this is food for thought and a chance to look at your own practice and see if it is in need of a tweak…
I think it is safe to say that this topic stirs up emotions on both sides of the argument of how aggressive to be when it comes to resuscitating some of these infants, particularly those at 22 and 23 weeks. Where I work we have drawn a line at 23 weeks for active resuscitation but there are those that would point out the challenge of creating such a hard-line when the accuracy of dating a pregnancy can be off by anywhere from 5 – 14 days. Having said that, this is what we have decided after much deliberation and before entertaining anything further it is critical to determine how well these infants are doing not just in terms of survival but also in the long run. In the next 6 months our first cohort should be coming up for their 18 month follow ups so this will be an informative time for sure.
Do Days Matter?
This is the subject of a short report out of Australia by Schindler T et al. In this communication they looked at the survival alone for preterm infants in a larger study but broke them down into 3 and four-day periods from 23 to 25 weeks as shown below.
The asterisk over the two bars means that the improvement in survival was statistically significant between being born in the last half of the preceding week and the first half of the next week. In this study in other words days make a difference. A word of caution is needed here though. When you look at the variation in survival in each category one sees that while the means are statistically different the error bars show some overlap with the previous half week. At a population level we are able to say that for the average late 23 week infant survival is expected to be about 30% in this study and about 55% at 24 +0-3 days. What do you say to the individual parent though? I am not suggesting that this information is useless as it serves to provide us with an average estimate of outcome. It also is important I believe in that it suggests that dating on average is fairly accurate. Yes the dates may be off for an individual by 5 – 14 days but overall when you group everyone together when a pregnancy is dated it is reasonably accurate for the population.
Don’t become a slave to the number
The goal of this post is to remind everyone that while these numbers are important for looking at average outcomes they do not provide strict guidance for outcome at the individual level. For an individual, the prenatal history including maternal nutrition, receipt of antenatal steroids, timing of pregnancy dating and weight of the fetus are just some of the factors that may lead us to be more or less optimistic about the chances for a fetus. Any decisions to either pursue or forego treatment should be based on conversations with families taking into account all factors that are pertinent to the decision for that family. Age is just a number as people say and I worry that a graph such as the one above that is certainly interesting may be used by some to sway families one way or another based on whether the clock has turned past 12 AM. At 23 weeks 3 days and 23 hours do we really think that the patient is that much better off than at 24 weeks 4 days and 1 hour?
What follows is a news release from today that begins a new chapter in supporting preemies here in Manitoba. There are far too many people to thank who made this possible but to all I say THANK YOU!
New Breast Milk Drop Site at the Birth Centre Benefits Premature and Sick Infants
DECEMBER 2, 2015 (WINNIPEG, MB) – The Winnipeg Regional Health Authority (WRHA) announced today a milk drop site is being established at the Birth Centre (603 St. Mary’s Road) in Winnipeg. Minister Blady announced the collaboration between Women’s Health Clinic and the NorthernStar Mother’s Milk Bank.
Registered donations of breast milk will be accepted by the Birth Centre in Winnipeg and transported for pasteurization at NorthernStar’s lab in Calgary. The pasteurized human milk from donors will be used to help premature and sick babies in neonatal intensive care units in hospitals, and in the community, across Canada.
“There can be a number of reasons why a mother may not be able to provide breast milk for her baby,” said Health Minister Sharon Blady. “This new Milk Drop site will help families ensure premature and sick babies get the best possible start in life by providing pasteurized donor human milk an infant needs to not only survive, but thrive.”
The minister noted that establishing a human milk drop supports recommendations made in the Manitoba Breastfeeding Strategy, released in 2013.
The WRHA purchased a freezer for the milk drop with funds provided by the Winnipeg-based Siobhan Richardson Foundation. The Birth Centre will house the freezer and ensure the safe handling and storage of donated human milk before it is shipped to Calgary for processing.
“My thanks and appreciation goes out to the Siobhan Richardson Foundation for supporting new moms as well as our tiniest patients,” said Dana Erickson, Chief Operating Officer, Health Sciences Centre and WRHA executive responsible for child health and women’s health. “This milk drop initiative in Manitoba is a reality because of their vision and generosity along with the commitment and hard work of our excellent health care team.”
Studies have shown premature infants who receive the nutrients of pasteurized human milk from donors, when their mother’s own milk is not available, have fewer long-term health needs. The use of pasteurized donor human milk instead of formula can reduce the risk of serious health complications in pre-term infants. Having a dedicated milk supply for these babies can save lives.
“Several health outcomes for preterm infants are improved when pasteurized donor human milk, rather than formula, is used in these high risk infants,” said Dr. Michael Narvey, section head of neonatology for the Winnipeg Regional Health Authority. “Pasteurized donor human milk has been proven to reduce the chances of an infant developing a serious condition of the bowel which can lead to lifelong and serious health consequences. Babies weighing less than 1500 grams are significantly less likely to develop this serious condition when they are given pasteurized human milk from donors as opposed to formula.”
Starting January 4, 2016, the Birth Centre will accept breast milk from donors approved by NorthernStar Mothers Milk Bank (formerly the Calgary Mothers Milk Bank). Women must first contact the NorthernStar Mothers Milk Bank to be screened prior to dropping off their donation at the Birth Centre. Women will then need to have further screening including blood tests by their primary care provider to confirm if they qualify as a donor. These donations will be sent to the milk bank’s lab in Calgary where the donor milk is tested, pasteurized, and then prioritized for premature and sick infants.
“We are excited to see Manitoba’s first Milk Drop opening in Winnipeg,” said Janette Festival, Executive Director, NorthernStar Mothers Milk Bank. “This Milk Drop is a testament to cooperation of multiple groups who believe in the medical power of donor human milk for babies in need. We hope this new ‘drop’ will encourage women in the Winnipeg area to consider becoming a milk donor.”
Women’s Health Clinic operates the Birth Centre facility and community programming, and will be collecting the donations and shipping them to the milk bank for testing and pasteurizing.
“Women and families come to the Birth Centre every day for a range of maternal health and wellness services, making it an ideal location for the new Milk Drop site,” said Joan Dawkins, Executive Director of Women’s Health Clinic. “Women who are interested in donating can get the process underway now by contacting NorthernStar Mothers Milk Bank.”
To donate, mothers can contact the milk bank at 1-403-475-6455 or visit NorthernStarmilkbank.ca.