LMA IN NEONATE RESUS

A study in Resuscitation looking at the efficacy of LMA’s in neonatal resuscitation. Usually we use a face mask and bag them. This study shows a tiny LMA might be a better choice. So get your LMA size 1 ready for the newborn resus trolley.

Objective: To study the feasibility, efficacy and safety of using the laryngeal mask airway (LMA) in neonatal resuscitation.
Methods: In total, 369 neonates (gestational age≥34 weeks, expected birth weight≥2.0 kg) requiring positive pressure ventilation at birth were quasi-randomised to resuscitation by LMA (205 neonates) or bag-mask ventilation (164 neonates).
Results: (1) Successful resuscitation rate was higher with the LMA compared with bag-mask ventilation (P < 0.001) and the total ventilation time was shorter with the LMA than with bag-mask ventilation (P < 0.001). Seven of nine neonates with an Apgar score of 2 or 3 at 1 min after birth were successfully resuscitated in the LMA group, while in the BMV group all six neonates with an Apgar score of 2 or 3 at 1 min required tracheal intubation and ventilation. In neonates with an Apgar score of 4 or 5 at 1 min after birth, successful resuscitation rate with the LMA was higher than with bag-mask ventilation (P < 0.01). (2) Successful insertion rate of the LMA at the first attempt was 98.5% and the insertion time was 7.8 s±2.2 s. There were few adverse events (vomiting and aspiration) in the LMA group.
Conclusion: The LMA is safe, effective and easy to implement for the resuscitation of neonates with a gestational age of 34 or, more weeks.

A prospective evaluation of the efficacy of the laryngeal mask airway during neonatal resuscitation, Resuscitation 2012.

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5 Responses to LMA IN NEONATE RESUS

  1. stefan mifsud says:

    What were the neurological out comes ? What is the chance of carotid artery compression when the cuff is inflated?

  2. Thomas D says:

    Interesting points. The study doesn’t follow up long enough to give definite answers to neuro outcome. LMAs compromising flow in the carotids has certainly been debated lately. In pigs with cardiac arrest, it might seem as it’s a bad idea to use supraglottic devices: http://www.scancrit.com/2012/04/27/supraglottic-airway-devices-cerebral-bloodflow/
    In people with cardiac arrest, we don’t really know. In people with a functioning circulation, millions of patients have proved the LMA’s safety and efficiency.

    Now, it would seem that *if* LMAs compress the carotids and compromise flow, they do so when the circulation stops, and there’s no pressure (apart from the artery’s natural stiffness) to fight the external LMA pressure.

    In infant resuscitation, the problem is usually an airway/breathing problem, and you still have circulation (with varying degrees of bradycardia). In these patients, I think an LMA will be fine. As always, keeping the cuff pressure as low as possible while still keeping the seal.

    My first choice for airway management in an infant resuscitation is bag valve mask, then intubate. If there are any difficulties with mask/intubation, I will now think about reaching for the LMA. It might be worth thinking about replacing it with a tube after the situation is under control.

    This strategy also goes for a neonate cardiac arrest, because if the patient doesn’t get any oxygen at all, I’m pretty sure I can predict the neurological outcome.

  3. David Hutchon says:

    You do not state how the lungs were inflated once the LMA was in place. did you use a BVM (less the mask) or did you have PEEP or some other pressure controlled supply of gas ?

    • Thomas D says:

      Hi David, thanks for your comments, but I’m not sure what situation you’re referring to? In the study? I’m not sure if they mention that. In my practice? I prefer something like the Neopuff (http://www.fphcare.com/products/neopuff-infant-resuscitator/) which delivers pressure controlled breaths and PEEP, but I will use a BVM style neonate bag if not. I prefer to have PEEP available.

      An LMA will also have a risk of air leak into the ventricle, just as in mask ventilation. So for LMA ventilation a Neopuff is probably better. In adults, I often find an apparent leak in the LMA while bagging manually disappears when the patient is put on the ventilator. I suspect the same might be true with neonates.

      For neonate resus, beware of filling the ventricle with air. It can get nasty. Not as much because of aspiration, but because an inflated ventricle in neonates can get big enough to hamper lung inflation and even circulation. Always drain air from the ventricle if you get into trouble during neonate resus.

      Any other thoughts on these issues?

      • David Hutchon says:

        Dear Thomas,
        Thank you that is very helpful. I was referring to use of a Neopuff or other PEEP apparatus such as the Tom Thumb. These will give much more reliable and consistent pressures than is possible with a BVM.

        You talk about air in the ventricle. Is this the stomach ? (I think air in the ventricle of the heart would not be possible and if it happened fatal !)

        In my view PEEP ventilating with a TEE piece is very rarely ineffective in achieving a satisfactory inflation of the lungs. It is critical with a neonate to get an good FRC with the first few inflations. If the first few inflations are ineffective and only get a small amount of air in the lungs, only a small part of the lung inflated then subsequent ventilation can fail to fully inflate the remaining lung, which might only get inflated when the neonate starts to create negative pressures in the chest with respiratory effort. I have no proof but there is no question that positive pressure ventilation does not have the same effect as the negative chest pressures of spontaneous breathing. Of course if the baby has already taken a few spontaneous breaths then needs assisted ventilation this might not be the same problem. How many of your babies had had no respiratory effort whatsoever ? It is not unusual for a compromised baby to take a breath soon after birth (a gasp) but no more after this. I suspect that this response is often associated with some degree of hypovolaemia, which is made worse by the blood required to fill the lungs, a less acute version of hypovolaemia than suggested by Mercer http://www.sciencedirect.com/science/article/pii/S0306987708005859
        I believe we should compliment our attempts at ventilating the lungs through the continued oxygen supply from the placenta shown by Wiberg et al to continue for at lest 90 seconds, a vital 90 seconds when resuscitation is concerned. Like a lot of other aspects of neonatal resuscitation unproven by an RCT but common sense to some.

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