How long should delayed cord clamping really be?

How long should delayed cord clamping really be?

by | Aug 28, 2019 | Cord management

The story around cord management after birth continues to be an evolving one. I have certainly posted my own thoughts on this before with my most recent post being Delayed cord clamping may get replaced. Time for physiological based cord clamping. While this piece demonstrated that there are benefits to longer times till clamping is done, it also showed that if you go too long hypothermia becomes a real risk and with it possible complications. At least in our centre the standard that we have tried to reach is DCC for one minute for our infants. As you will no doubt know from the literature reviewed here before, this is likely not long enough!

One or Three Minutes?

This study caught my eye this week. Effect of early versus delayed cord clamping in neonate on heart rate, breathing and oxygen saturation during first 10 minutes of birth – randomized clinical trial What struck me in particular about this paper was not just the physiologic outcomes it was looking at. What is remarkable is the size of the study. So many articles that are published in Neonatology have under a hundred patients. On occasion we see studies with hundreds. In this case the authors included 1510 patients who were randomized to early ≤60 s of birth and ≥ 180 s for time of clamping. What is also interesting here is that early which used to be considered right after delivery of the infant is now 1 minute in this study. I like that this is the accepted new norm for this type of study.

Inclusion criteria were such that these were all low risk vaginal deliveries with fetal heart rate (FHR) ≥100 ≤ 160 bpm and all infants were ≥33 weeks. Although 1510 were randomized (power calculation for sample size found there should be 566 per group based on an expected loss of 25% per arm. In the end there were 670 in the ECC and 594 in the DCC groups that adhered to the protocol. In the ECC group the mean duration of time till clamping occurred was 31.2 s (+/-14.4) vs 198.5s (+/-16.9).

The Results

The goal after delivery is to increase blood flow to the lungs as PVR drops. In order to do so this requires adequate ventilation but it also requires adequate perfusion of the myocardium. If you clamp too early and pulmonary blood flow has not yet increased you run the risk of having a sudden drop in coronary blood flow with oxygenated blood from the placenta and with that bradycardia.

A longer time on “heart lung bypass” from the placenta should allow for a smoother transition. That is what was seen here. At 1, 5 and 10 minutes infants randomized to the DCC had better oxygen saturations. Heart rates interestingly were lower in the DCC group but that could also be related to better oxygenation leading to less compensatory tachycardia. In other studies in which the cord was clamped immediately bradycardia was more common. This difference here may reflect timing of the clamp on heart rate. Lastly, time to first breath was much faster in the group randomized to DCC. Might this be an effect of better oxygenation?

What they didn’t measure?

There was no comment on risk of hypothermia or other markers of illness such as rates of admission to NICU, hypoglycemia, lethargy or other markers of an infant who became cold. If this is to become standard practice measures need to be in place to prevent these concerns from becoming reality. It is also worth noting the population studied. These are healthy late preterm and term pregnancies. More work is needed on younger infants and those with risk factors in pregnancy. How would mothers with poor tracings, diabetes or hypertension fare as well as those who have growth restricted infants?

This field is growing and I will continue to follow this evolving story and share information as it becomes available. One thing in my mind is fairly certain though and that is that clamping right after delivery for routine births should be a thing of the past.

Sedation before LISA/MIST? Is it safe?

Sedation before LISA/MIST? Is it safe?

by | Aug 15, 2019 | intubation

I knew it was a matter of time before a study looking at this strategy came out. Whether you intubate using INSURE or a LISA/MIST technique (passing a semi-rigid catheter through the vocal cords to give surfactant while a baby is on CPAP) there would have to be those that argue the placement of the laryngoscope blade in the mouth and passage of the catheter through the trachea must be uncomfortable. Given such concerns, why wouldn’t you want to provide some sedation to the patient? The main concern would be suppression of respiratory drive and need for intubation or PPV. LISA/MIST usage has been found in systematic reviews to lead to less risk of BPD but what if sedation leads to more PPV especially with uncontrolled tidal volumes on these fragile lungs? Will the benefits remain?

Propofol Before MIST

Dekker et al published Sedation during minimal invasive surfactant therapy: a randomised controlled trial in which they looked at infants receiving surfactant administration by MIST in infants born at 26 – 36 weeks with stratification of results into two groups (26–31+6 and 32–36+6 weeks). The intervention was to give a relatively small dose of propofol 1 mg/kg compared to the typical dose of 2.5 mg/kg prior to using MIST. Physicians were unblinded to the intervention but nurses were asked (they were blinded) to determine the COMFORTneo score as a measure of discomfort or pain. The primary outcome was the percentage of infants with a score <14 during the procedure. A power calculation to determine numbers needed for the study indicated 39 per arm and was based on a previous study (not using propofol though). While it does not appear that a sham was used for a placebo arm, sucrose was utilized for additional comfort in both arms.

The Results Please

Sedation seemed to work even at this lower dose of propofol as the group who received it had a higher percentage with a score <14 (32/42 (76%) vs 8/36 (22%), p<0.001). Moreover, the overall mean scores were also lower (12±3 vs 17±4; p<0.001). When looking at rates of complications though some interesting but perhaps not surprising findings emerge. A greater risk of desaturation events existed in the group receiving even a low dose of propofol.

Digesting this information it would seem that giving propofol prior to MIST may defeat the purpose of avoiding positive pressure ventilation as nearly all patients given propofol required nasal intermittent mandatory ventilation. As this is a small study we have to take the secondary outcomes with a grain of salt as the study would not have been powered to detect all these important outcomes such as IVH and pulmonary hemmorhage. Moreover the real question here would be whether BPD would be different between the groups but again not reported and even if it had been the numbers would be a little low to see a real difference.

The next steps I think will be to look at this question using medications such as atropine and fentanyl which I understand in other centres are in use. To do so though will require some pretty big numbers for enrolment. in the meantime what are we to do? Putting a catheter into the trachea I would think would be uncomfortable if not painful. Something should be given prior to the procedure but it is now on the research community to determine what that is and a what dose!