Head cooling criteria

[Saidy]

Hi Netters, I would like to explore the head cooling criteria. the criteria of the three largiest clinical trial of hypothermia are basically evidence of fetal acidemia, low apgar scores, the need for active resuscitation and clinical signs of encephalopathy +/- CFM monitoring. Although we are following these criteria but we may miss cases of moderate HIE. for example there is an evidence of perinatal sentinle event, cord pH 7.0 and BE -12, Apgar scores 6 & 8 @ 1 and 5 minutes. no active resuscitation required but at 10 hours of age the baby developed clinical seizure ( we missed the theraputic window for head cooling) and the work up R/O the common causes of seizurs.

Does this kind of senario happen in your unit? what do you do to avoid such a problem?

[Stefan Johansson]

I think (personally) that it is easy to miss some cases like this, as well as that some infants are cooled that do not really full-fill cooling criteria. Especially as infants with moderate HIE seem to benefit more than those with a severe HIE.

We have a 2-step procedure - first a baby need to fulfill A-criteria and then we evaluate if the baby has B-criteria. Only those ful-filling B-criteria are cooled.

Practically the A-criteria means that at least one of the following are ful-filled:

- Apgar at 10 minutes ≤ 5

- resuscitation (incl ≥mask ventilation) at 10 minutes of age

- pH < 7.0 during the first hour (arterial or capillary)

- BE ≤- 16 during the first hour

The B-criteria are that the infant has HIE grade 2 or 3, as judged clinically

- letargia, stupor or coma and

- changed tonicity and

- altered primitive reflexes (grip/moro/suction)

[Saidy]

I feel sorry for those who did not full-fill the cooling criteria initially, however later on they developed repeated seizures. My observations that most of them have abnormal neurological exam. So can we initiate head cooling based on clinical assessment and we can stop at any stage if we feel that we are not dealing with HIE, i.e. give the patient the benefit of doubt.

[amgraca]

Those moderate cases are sometimes difficult to decide clinically in terms of B criteria and that is the reason why we still use the aEEG criteria as was done during the TOBY trial. As most our patients are outborn, we recommend maintaining "passive" hypothermia (34-35ºC) during transport, and on arrival we monitor aEEG for a while. If it is normal voltage (alNaqeeb criteria) and we see no seizures we do not cool the baby. If aEEG is not normal voltage or if there are seizures we will cool the baby for sure. This approach is much more objective than the B criteria, and using it allows us not to overtreat patients that will probably be normal and also trat babies that despite having a reasonable clinical picture have an abnormal aEEG and definitely benifit from treatment.

[Dinesh N Patel]

Der Saidy

i was witness one pt in recent past.the FT infant had persistent FETAL bradycardia ,THE MOTHER was on ventilator for severe CNS hemorrhage with ,brain death.relative were offered for em cs to save baby.the baby resuscitated. spontaneous respiration established welL within 2min, cord blood ph 7 .BE , -12 APGAR 3/1 7/5,TRANSFER TO NICU FOR further care,baby satlled ON AIR and maintained spo2 on air .ABG also improved there was no apparent clinical sign. suggestive of HIE, AFTER 10 HR BABY HAD EXCESSIVE CRYING ,ARF, CONVULSION altered sensorium AND SIGNS OF HIE. WE DON'T HAVE CFM FACILITY.we OFFERED RELATIVE TH.TH GIVEN FOR 72 HOUR FORTUNATELY WE ARE ABLE TO DISCHAGED ON bottle feeding , CNS examination was normal on discharged .if we have CFM FACILITY THAT MIGHT HELP US IN THIS CASE TO PICK UP HIE EARLIER.

dinesh

[Saidy]

So head cooling was offered after 6 hours of age and apparently with favorable outcome. How frequent did our netters offer head cooling beyond 6 hours of age and what was the outcome?

[Francesco Cardona]

I also believe it is tricky to identify the baby with moderate HIE. We also like to use the aEEG for additional information beyond neonatal neurologic exam. In general we have become more willing to offer hypothermia to more babies in accordance with the latest trial. In a few cases we have also treated babies beyond the first 6 hours of age, but most of the time we would have the babies at our ward early enough to initiate treatment for babies born outborn.

[selvanr4]

is there a learning place for aEEG ? can we use conventional EEG with any modifications for augmentation?

Who does the reading of these and neonatal EEGs? what is the main difficulty experienced in interpreting?

thanks in advance.

[Dinesh N Patel]

aEEG is more simple in interpretation than EEG,became popular for cerebral function monitor in HIE .

Here is a link for aEEG:http://www.neoweb.org.uk/CFM/CFM6000+manual.pdf

NOTE NEUROLOGY MODULE is very good learning place on line learning for aEEG AND its role in neonatal HIE after perinatal asphyxia.continous cerebralfunction monitoring- aEEG after birth with h/o birthasphyxia helps to identify abnormal cerebral function in borderline case and early inclusion in selection for therapeutic hypothermia

dinesh

i

[selvanr4]

Thanks for the link

I am more than willing take NOTE neurology module with your recommendations

[amgraca]

is there a learning place for aEEG ? can we use conventional EEG with any modifications for augmentation?

Who does the reading of these and neonatal EEGs? what is the main difficulty experienced in interpreting?

thanks in advance.

aEEG is much simpler but it requires some formal training. Besides the excellent tools provided by Prof Azzopardi at his site, I think Prof. Thoresen at Bristol are providing teaching on aEEG and hypothermia regularly.

I would say that it required at least one year of training of our staff to have absolutely reliable aEEG interpretation by our medical team. As this was more than 5 years ago it became easier to implement cooling according to the TOBY protocol.

Concerning the therapeutic window I would say that we should stick to less than 6 hours until a neuroprotective temperature is reached but this does not mean that we should exclude a baby that arrives at 9 hours, provided that a temperature between 34-35 was reached before 6 hours (during transport or at the referring hospital).