We were interested to read the experiences of other units 1-4 sharing
their findings of increased duration of antibiotics, length of stay in
hospital and lumbar punctures (LP) performed following implementation of
the NICE guideline on prevention of early onset neonatal infection
(EONI)5. We recently changed our practice to follow these NICE
recommendations advocating observation of low risk infants to reduce
antibiotic...
We were interested to read the experiences of other units 1-4 sharing
their findings of increased duration of antibiotics, length of stay in
hospital and lumbar punctures (LP) performed following implementation of
the NICE guideline on prevention of early onset neonatal infection
(EONI)5. We recently changed our practice to follow these NICE
recommendations advocating observation of low risk infants to reduce
antibiotic exposure whilst commencing antibiotics in those deemed higher
risk 5. We have not yet found that the change in practice has increased
our infant's length of stay, antibiotic days or LPs performed.
In the two months (September/October) prior to our change of
practice, 69 babies were treated with IV antibiotics, averaging 2.4
babies/day, with 33.3% requiring treatment for >24hrs. In the two
months (November/December) following the new guideline implementation a
total of 66 babies required antibiotics, averaging 1.7 babies/day with
21.1% requiring treatment for >24hrs. We have seen no increase in the
frequency of LPs performed since the change (5 babies total
September/October vs. 2 November/ December). We have seen additional
testing in the form of repeat FBC, UEs, LFTs for the small number of
babies continuing antibiotics >24 hours as recommended by NICE (5 in
the first month following implementation). We recognise this is a small
sample population but our findings do not suggest a trend towards an
increase in antibiotics or invasive procedures as experienced by other
centres 1-4.
We acknowledge that the wide variation in clinical practice prior to
the publication of NICE EONI guidelines makes it challenging to compare
findings between units and may account for the differences observed. For
example, we have always investigated infants receiving antibiotics with an
initial CRP/blood cultures and repeat CRP at 18-24 hours to inform the
decision to cease antibiotics. Conversely, our colleagues' letters suggest
the second CRP is a change in their practice and therefore may account for
the increased antibiotic duration they observed 1-4.
Variation in the threshold to perform an LP may account for the
differing trends in frequency between units. NICE suggests consideration
of LP with a CRP >10 2. Locally we do not have a set CRP number that
would prompt an LP but make this decision based upon the baby's clinical
picture with acknowledgment of the CRP. In our babies that had an LP,
their CRP's ranged from 24-160. In our first month post-implementation we
saw 5 babies with a CRP rise (13-25) that necessitated a prolonged
antibiotic course but did not have an LP as the baby was clinically well,
with no signs of CNS involvement.
We have developed a monitoring chart, the Neonatal Early Warning
Score (NEWs) in order to record observations for all babies at risk of
EONI. In our first month we saw 51 babies on NEWs monitoring - 32 required
antibiotics and 16 on NEWs monitoring only. Despite initial concerns of
increased workload for postnatal staff these charts have embedded into
practice with the majority of infants (78%) appropriately commenced on the
chart for the required time period and we hope this will improve with
further familiarity and education. We acknowledge that our experiences are
early but we will continue to practice the new guideline following an
audit that has identified no significant issues or clinical concerns.
Further audit will be undertaken in due course, combined with other units
in our MCN who are shortly integrating the new guideline into their
practice.
References
1) Naydeva-Grigorova T, Manzoor A, Ahmed M. Arch Dis Child Fetal
Neonatal Ed 2015; 100:F93-F94.
2) Mukherjee A, Davidson L, Anguvaa L et al. NICE neonatal early
onset sepsis guidance: greater consistency, but more investigations, and
greater length of stay. Arch Dis Child Fetal and Neonatal Ed. Published
online first: 25 Jul 2014 doi:10.1136/archdischild-2014-306349
3) Mukherjee A, Ramalingaiah B, Kennea N et al. Letter: Management of
neonatal early onset sepsis (CG149): compliance of neonatal units in the
UK with NICE recommendations. Arch Dis Child Fetal Neonatal Ed. Published
Online First: 19 December 2014 doi:10.1136/archdischild-2014-307776
4) Mukherjee A, Davidson L, Anguvaa L et al. Short research report:
NICE neonatal early onset sepsis guidance: greater consistency, but more
investigations and greater length of stay. Arch Dis Child Fetal Neonatal
Ed. Published Online First: 25 July 2014 doi:10.1136/archdischild-2014-
306349
5) http://www.nice.org.uk/guidance/CG149 (accessed 19 Jan 2015)
The alternative explanation for the cardiovascular differences
between immediate and delayed cord clamping at birth suggested in this
commentary is not new and has been acknowledged for over 50 years. The
basic premise is that asphyxia is the underlying cause of birth-related
bradycardias and that avoiding asphyxia will avoid the bradycardia and
associated cardiac instability. However, neonatologists have known for
almo...
The alternative explanation for the cardiovascular differences
between immediate and delayed cord clamping at birth suggested in this
commentary is not new and has been acknowledged for over 50 years. The
basic premise is that asphyxia is the underlying cause of birth-related
bradycardias and that avoiding asphyxia will avoid the bradycardia and
associated cardiac instability. However, neonatologists have known for
almost as long that lung aeration is the primary consideration when
resuscitating bradycardic infants at birth. While it was thought that the
beneficial effects are due to increased oxygenation, the Bhatt (1) study
showed that increasing pulmonary blood flow and restoring venous return
lost due to cord clamping, was also a major contributing factor. This is
supported by studies in asphyxic, bradycardic lambs (2).
Although the association between severe asphyxia and bradycardia is well-
established, most birth related bradycardias are unlikely to be caused by
asphyxia. Indeed, the birth-related cardiovascular changes are often
unrelated to changes in oxygenation, which is shown in the heart rate
normograms published by Dawson (3) et al. In normal healthy term infants,
over 50% had a heart rate below 100 bpm at 1 min after birth and in some
infants, the heart rates increased while oxygenation remained unchanged or
decreased. The Bhatt et al (1) study was designed to replicate a
relatively common clinical scenario, whereby the elapsed time between
delivery, cord clamping and effective ventilation onset is ~2min. As
preterm infants are commonly given an opportunity to transition unassisted
at birth, a 2 min time window between birth and the onset of effective
respiratory support is not uncommon. To put this into context, lambs at
this age do not initiate gasping until 4-5 min after cord clamping, can
easily be resuscitated after 10 min and take 12-13 min before becoming
asystolic (4). In the Bhatt (1) study, lambs did not gasp and heart rates
did not decrease below 100 bpm and so they were only mildly asphyxic at
worst.
As the fetal heart rate (in utero) responses to cord clamping markedly
differ from the heart response to cord clamping ex utero (4), making
conclusions about neonatal cardiac responses based on fetal data is
problematic. Similar problems arise if the newborn's face is surrounded by
liquid (4). We note that in the study cited by the author, a saline-filled
bag was placed over the lamb's head and the lambs were ventilated via a
tracheostomy. Nevertheless, the alternative interpretation of their
findings is that reducing the timing between cord clamping and ventilation
onset leads to a more labile transition not because of oxygenation
differences, but because it reduces the time that venous return and
cardiac output are reduced. This is consistent with the conclusion of
Bhatt et al (1).
We disagree with the author's suggestion that avoiding asphyxia will by
itself improve cardiovascular stability at birth. This is not only because
of the reasons cited above, but because this simple view of the physiology
surrounding transition will encourage clinicians to intervene and attempt
to assist infants earlier than is perhaps necessary.
1. Bhatt S, Alison B, Wallace EM, et al. Delaying cord clamping until
ventilation onset improves cardiovascular function at birth in preterm
lambs. J Physiol. 2013;591:2113-26.
2. Klingenberg C, Sobotka KS, Ong T, et al. Effect of sustained
inflation duration; resuscitation of near-term asphyxiated lambs. Arch Dis
Child Fetal Neonatal Ed. 2013;98:F222-7.
3. Dawson JA, Kamlin CO, Wong C, et al. Changes in heart rate in the
first minutes after birth. Arch Dis Child Fetal Neonatal Ed. 2010;95:F177-
81.
4. Sobotka KS, Morley C, Ong T, et al. Circulatory Responses to
Asphyxia Differ if the Asphyxia Occurs In Utero or Ex Utero in Near-Term
Lambs. PLoS One. 2014;9:e112264.
The review by Hooper et al1 is timely and mounts a compelling case
for a stable circulatory transition during preterm birth. However,
advocacy of early ventilation with delayed cord clamping as the primary
way forward to ensure such a transition is open to question, as the main
supportive evidence for this paradigm comes from an experimental study by
the same group,2 for which an alternative interpretation of observed
f...
The review by Hooper et al1 is timely and mounts a compelling case
for a stable circulatory transition during preterm birth. However,
advocacy of early ventilation with delayed cord clamping as the primary
way forward to ensure such a transition is open to question, as the main
supportive evidence for this paradigm comes from an experimental study by
the same group,2 for which an alternative interpretation of observed
findings has recently come to light.
Thus, in preterm lambs, Bhatt et al2 reported relatively minor perinatal
changes in heart rate, blood pressure and right ventricular output with
early ventilation and delayed cord clamping. By contrast, early cord
clamping followed by ventilation 2 minutes later was associated with 1)
bradycardia, arterial blood pressure swings and large reductions in right
ventricular output before ventilation, and 2) substantial rises in heart
rate, blood pressure and right ventricular output after ventilation.
The 2 minute interval employed by Bhatt et al2 between early cord clamping
and the onset of ventilation is potentially problematic, however, as prior
studies in fetal lambs have shown that asphyxia can develop within 2
minutes after complete occlusion of uterine arteries or the umbilical
cord.3 4 Indeed, a preterm lamb birth study employing a lesser cord clamp-
to-ventilation interval (1.5 minutes) has now shown that an asphyxial
state rapidly develops by 45 seconds after cord clamping on aortic blood
gas analysis, with a haemoglobin O2 saturation of <10% and O2 tension
of <10 mmHg, associated with a fall in pH and rise in CO2 tension.5
Furthermore, similar to the onset and offset phases of brief in utero
asphyxia,3 4 this asphyxial state was accompanied by 1) bradycardia,
marked falls in ventricular outputs/central blood flows and redistribution
of systemic flow towards the brain before ventilation, and 2) tachycardia
with blood pressure and flow surges after ventilation.5 These data
therefore suggest that the findings of Bhatt et al2 primarily reflected
the haemodynamic effects of asphyxia occurring with an extended cord
clamping-to-ventilation interval, rather than beneficial effects per se of
early ventilation with delayed cord clamping.
Consistent with the foregoing proposition, reducing the cord clamping-to-
ventilation interval from 1.5 to 0.5 minutes (to avoid development of an
established asphyxial state) markedly blunted perinatal haemodynamic
fluctuations.5 This finding thus implies that circulatory stability during
the preterm birth transition hinges on avoidance of asphyxia. Such
avoidance can be achieved not only with the advocated paradigm of early
ventilation and delayed cord clamping,1 but also with early cord clamping,
if this is followed by a short interval before the onset of ventilation.5
References
1. Hooper SB, Polglase GR, te Pas AB. A physiological approach to the
timing of umbilical cord clamping at birth. Arch Dis Child Fetal Neonatal
Ed 2014; DOI: 10.1136/archdischild-2013-305703.
2. Bhatt S, Alison BJ, Wallace EM, et al. Delaying cord clamping until
ventilation onset improves cardiovascular function at birth in preterm
lambs. J Physiol 2013;591:2113-26.
3. Jensen A, Garnier Y, Berger R. Dynamics of fetal circulatory responses
to hypoxia and asphyxia. Eur J Obstet Gynecol Reprod Biol 1999;84:155-72.
4. Hunter CJ, Blood AB, Power GG. Cerebral metabolism during cord
occlusion and hypoxia in the fetal sheep: a novel method of continuous
measurement based on heat production. J Physiol 2003;552:241-51.
5. Smolich JJ, Kenna KR, Cheung MM. Onset of asphyxial state in non-
respiring interval between cord clamping and ventilation increases
hemodynamic lability of birth transition in preterm lambs. J Appl Physiol
2015; DOI: 10.1152/japplphysiol.01147.2014.
From: Dr Janet M Rennie Dr Giles S Kendall (NICU UCLH London)
Dr Caroline May (NICU & NTS The Royal London Hospital, London)
Comment on: Neonatal Airway Practices: Whitby T et al ADC Fetal and
Neonatal Edition 2015:100: F92-93
We read the letter from Whitby et al regarding neonatal airway
practice with interest. We agree that neonatal units need a "difficult
airway" trolley, a guideline, and a "Can't Intubate, Can't ventilate"
(CICV) algorithm. Like many units, we have thought hard about this over
the last year and have reflected on our own clinical experiences.
We suggest that the CICV algorithm proposed by Whitby et al is not
suitable for translation to the newborn. There are several reasons why the
newborn require a special approach; this is not "inequality". Most
importantly, as pointed out by Johansen and colleagues, the cricothyroid
space is simply too small to cannulate in a neonate and surgical
cricothyrotomy is not an option (Johansen et al., 2012). Very few neonatal
units would be able to obtain the services of an experienced paediatric
ENT surgeon, or have the equipment for emergency tracheostomy, and this is
only feasible in the larger term newborn even then and very few patients
are unconscious at the time of acute airway compromise. Storz
laryngoscopes (and other indirect laryngoscopes) are fantastic aids but it
is impractical for such valuable equipment to form part of a "difficult
airway" set kept in storage on a neonatal unit.
We have had good success with the use of a bougie and the "railroad"
technique, which is not mentioned at all in the algorithm proposed by
Whitby et al. Laryngeal mask airways can certainly help, and the Igel
devise looks promising. Further, a neonatal algorithm needs to recognise
the possibility of a congenital problem such as Pierre Robin sequence,
which requires recognition and special management (Abel et al., 2012)
(Evans et al., 2011). Anticipation and planned securing of difficult
airways is particularly important where congenital anomalies are known and
rather disappointingly there is no mention of such planning in the Whitby
algorithm. Such plans often need to be bespoke and carefully considered
when facing such unique clinical situations and the baby's clinical
condition may in fact be exacerbated by cricothyrotomy/tracheostomy eg.
laryngeal web.
In short, we agree that a CICV algorithm and a realistic "difficult
airway" kit list are needed, but these need to be appropriate for the
newborn and to be achievable by all units.
Yours, etc..
Reference List
Abel, F., Bajaj, Y., Wyatt, M. & Wallis, C. (2012). The
successful use of the nasopharyngeal airway in Pierre Robin sequence: an
11-year experience. Arch Dis Child 97, 331-4.
Evans, K. N., Sie, K. C., Hopper, R. A., Glass, R. P., Hing, A. V. &
Cunningham, M. L. (2011). Robin sequence: from diagnosis to development of
an effective management plan. Pediatrics 127, 936-48.
Johansen, L. C., Mupanemunda, R. H. & Danha, R. F. (2012). Managing
the newborn infant with a difficult airway. Infant 8, 116-119.
We were interested to read the experiences of other units 1-4 sharing their findings of increased duration of antibiotics, length of stay in hospital and lumbar punctures (LP) performed following implementation of the NICE guideline on prevention of early onset neonatal infection (EONI)5. We recently changed our practice to follow these NICE recommendations advocating observation of low risk infants to reduce antibiotic...
The alternative explanation for the cardiovascular differences between immediate and delayed cord clamping at birth suggested in this commentary is not new and has been acknowledged for over 50 years. The basic premise is that asphyxia is the underlying cause of birth-related bradycardias and that avoiding asphyxia will avoid the bradycardia and associated cardiac instability. However, neonatologists have known for almo...
The review by Hooper et al1 is timely and mounts a compelling case for a stable circulatory transition during preterm birth. However, advocacy of early ventilation with delayed cord clamping as the primary way forward to ensure such a transition is open to question, as the main supportive evidence for this paradigm comes from an experimental study by the same group,2 for which an alternative interpretation of observed f...
To: The Editor, Archives of Disease in Childhood
From: Dr Janet M Rennie Dr Giles S Kendall (NICU UCLH London)
Dr Caroline May (NICU & NTS The Royal London Hospital, London)
Comment on: Neonatal Airway Practices: Whitby T et al ADC Fetal and Neonatal Edition 2015:100: F92-93
We read the letter from Whitby et al regarding neonatal airway practice with interest. We agree that neonat...
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