Me thinks Professor Sulyok doth protest too much. His early,
pioneering work on electrolyte balance in the newborn is well known (and
extensively cited in an earlier review of the subject co-authored by
myself.[1] In this, inter alia, his study of the effect of salt
supplementation on the renin-angiotensin-aldosterone system [2] is quoted in
support of the hypothesis that hyponatraemia in premature infant...
Me thinks Professor Sulyok doth protest too much. His early,
pioneering work on electrolyte balance in the newborn is well known (and
extensively cited in an earlier review of the subject co-authored by
myself.[1] In this, inter alia, his study of the effect of salt
supplementation on the renin-angiotensin-aldosterone system [2] is quoted in
support of the hypothesis that hyponatraemia in premature infants is due
to salt depletion rather than water retention). The reason these papers
were not cited in the present paper is that they are not relevant to it.
The paper is not a historical or general review of hyponatraemia in the
newborn but the results of a study specifically designed to examine
neurodevelopmental outcome in two particular groups of infants previously
studied by ourselves.[3-5] His recent study of hyponatraemia and
sensorineural deafness in preterm infants[6] had not been published when our
paper was submitted to the Archives, although we would certainly have
referred to it if it had been.
GEORGE HAYCOCK
References
(1) Haycock GB, Aperia A. Salt and the newborn kidney. Pediatr Nephrol 1991;5:65-70.
(2) Sulyok E, Németh M, Tényi I, Csaba IF, Varga L, Varga F. Relationship between the postnatal development of the renin-angiotensin-aldosterone system and the electrolyte and acid-base status in the sodium chloride supplemented premature infant. Acta Paediatr Acad Sci Hung 1981;22:109-21.
(3) Al-Dahhan J, Haycock GB, Chantler C, Stimmler L. Sodium homeostasis in term and preterm neonates. I. Renal aspects. Arch Dis Child 1983;58:335-42.
(4) Al-Dahhan J, Haycock GB, Chantler C, Stimmler L. Sodium homeostasis in term and preterm neonates.II. Gastrointestinal aspects. Arch Dis Child 1983;58:343-5.
(5) Al-Dahhan J, Haycock GB, Nichol B, Chantler C, Stimmler L. Sodium homeostasis in term and preterm neonates. III. The effect of salt supplementation. Arch Dis Child 1984;59:945-50.
(6) Ertl T, Hadzsiev K, Vincze O, Pytel J, Szabo I, Sulyok E. Hyponatremia and sensorineural hearing loss in preterm infants. Biol Neonate 2001;79:109-12.
In their study on time to positivity of neonatal blood
cultures, Kumar et al[1] conclude that a period of 36 hours is sufficient to
exclude sepsis in otherwise well neonates. They documented that the
negative predictive value of neonatal blood cultures at 36 hours is 98%
for definite or possible pathogenic bacteria. This is also true in our
experience using a different automated blood culture system...
In their study on time to positivity of neonatal blood
cultures, Kumar et al[1] conclude that a period of 36 hours is sufficient to
exclude sepsis in otherwise well neonates. They documented that the
negative predictive value of neonatal blood cultures at 36 hours is 98%
for definite or possible pathogenic bacteria. This is also true in our
experience using a different automated blood culture system to that
employed by Kumar et al[1].
We chose to analyse in detail, neonatal blood culture samples taken
within 48 hours of birth for two reasons. Firstly, neonates with early
suspected sepsis constitute a unique group, as the pathogens are usually
acquired intra-partum. Secondly, the impact on early cessation of
antibiotics and early discharge from the neonatal unit would potentially
be great in this group. We studied a total of 936 neonatal blood cultures
taken from November 1999 to October 2000 of which 189 (20.2%) were
positive. Of the total of 142 neonatal blood cultures taken within 48
hours of birth, the positivity rate was similar (19%). Organisms isolated
were classified as either pathogens or possible contaminants, based on the
identity of the organism, clinico-pathological markers like C-Reactive
Protein (CRP), neutrophil count and clinical picture. 15 of the 27
positive early neonatal blood cultures yielded pathogens. All the
significant cultures became positive within 27 hours of incubation in the
Vital automated blood culture system (bioMerieux, France).
The advent of automated blood culture detection systems allows
significantly earlier detection of most aerobic bloodstream pathogens than
manual systems[2]. Previous data supporting the need for longer
observation times utilized non-automated systems and were reported in an
era when the distribution of pathogenic micro-organisms causing infection
in neonatal units may have been different[3]. Also, as the incidence of
nosocomial neonatal septicaemia varies significantly between units, it is
important to validate locally any changes to current protocols[4]. We
conclude that negative blood cultures at 36 hours can be used to
discontinue antibiotics in cases of suspected early neonatal sepsis. We
encourage others to consider adopting this approach to minimise needless
use of antibiotics with consequent pressure for antimicrobial resistance.
References
(1) Kumar Y, Qunibi M, Neal TJ, Yoxall CW. Time to positivity of
neonatal blood cultures. Arch Dis Child Fetal Neonatal Ed 2001; 85: F182-
6.
(2) Rohner P, Pepey B, Auckenthaler R. Comparison of BacT/Alert with
Signal blood culture system. J Clin Microbiol 1995; 33: 313-7.
(3) Sidebottom DG, Freeman J, Platt R, Epstein MF, Goldmann DA.
Fifteen-year experience with bloodstream isolates of coagulase-negative
staphylococci in neonatal intensive care. J Clin Microbiol 1988; 26: 713-
8.
(4) Brodie SB, Sands KE, Gray JE, Parker RA, Goldmann DA, Davis RB,
Richardson DK. Occurrence of nosocomial bloodstream infections in six
neonatal intensive care units. Pediatr Infect Dis J 2000; 19: 56-65.
Dr da Costa et al, and Dr Gatrad in his accompanying commentary [Arch
Dis Child Fetal Neonatal Ed 2002;86:F115-9], are mistaken in drawing
convulsions about Muslim families in relation to ‘do not resuscitate
orders’. Gatrad suggests doctors should receive training in ethical
issues of other cultures. Firstly, it is impossible to know the religious
or historical or personal background of every parent....
Dr da Costa et al, and Dr Gatrad in his accompanying commentary [Arch
Dis Child Fetal Neonatal Ed 2002;86:F115-9], are mistaken in drawing
convulsions about Muslim families in relation to ‘do not resuscitate
orders’. Gatrad suggests doctors should receive training in ethical
issues of other cultures. Firstly, it is impossible to know the religious
or historical or personal background of every parent. Secondly, Muslims
are not an homogenous group, just as Buddhists or Baptists are not. To
assume that because someone has a particular surname (e.g., Singh, a name
usually associate with Sikhism) or comes from a particular country (e.g.,
India, where many people are Hindus) or is of a particular religion (e.g.,
Catholicism, as there are lapsed Catholics, middle of the road Catholics,
and ardent Catholics) that they have a particular set of beliefs is very
unwise. Indeed, it is racist. For example, I have an evangelical
Christian faith, which is probably different in some respects from many
other evangelical Christians. What would my views be on ‘do not
resuscitate’ if faced with that for my children? Whatever they are, I
would be annoyed if my children’s medical attendants assumed that I had
the same views as all evangelical Christians.
Which raises a third point. Why are such issues only considered for
‘ethnic minority’ groups? I have yet to read a paper or hear a
presentation on cultural aspects for Methodists, Plymouth Brethren, born
again Christians, etc. In the end, though, it doesn’t matter, and neither
do da Costa et al’s or Gatrad’s views. It is important to treat the
families with respect, and listen to them.
I do not know the situation in Oman, where da Costa works, but in the
UK I think the pendulum has swung too far in terms of how we involve
parents in ‘end of life’ decisions. The parents’ views are important but
not determinative. Society, and the Courts, have devolved those decisions
to doctors. To ask parents to be involved in those decisions about their
own children is an unfair burden for them to carry, possibly for the rest
of their lives.
The letter written by Patole [1] on bullying in neonatal intensive
care units (NICU) is misleading if it is meant to refer to the Neonatal
Intensive Care Unit at The Townsville Hospital. In two years working as
Senior...
The letter written by Patole [1] on bullying in neonatal intensive
care units (NICU) is misleading if it is meant to refer to the Neonatal
Intensive Care Unit at The Townsville Hospital. In two years working as
Senior Registrar I have found this NICU to be an extremely pleasant place
to work and would highly recommend it to paediatric and neonatal trainees
in Australia and overseas.
Like many Australian NICUs we often employ foreign registrars who may have
difficulty adjusting to our Australian way of life where there is less
regard for rank and where we respect the expertise of our (mostly female)
nursing staff.
The routine posing of basic questions to medical and nursing staff on the
morning round is welcomed by most of us as educational. The atmosphere is
supportive and it is hard to imagine someone being upset that the group as
a whole is asked "What are six causes of hyperglycaemia in a preterm
neonate?". However it has been brought to our attention that some foreign
trained doctors do perceive this as bullying, which was never the
intention.
The key response to the implied charge of bullying of registrars in The
Townsville Hospital NICU (formerly Kirwan Hospital for Women NICU) is the
sentence in Dr Koh's letter on "Harmony in the NICU"[2] which states: "It is
tragic and disturbing when a small proportion of doctors interpret
reasonable efforts by both senior nurses and consultants to ensure optimal
care of the babies in NICU as bullying". It appears that to avoid being
labelled as bullies, we must not ask doctors to perform routine tasks of
caring for babies such as filling out pathology forms, reviewing
deteriorating babies and completing discharge summaries. Supobtimal
performance and laziness are not conducive to good relationships between
staff in the NICU.
I have recently conducted a survey of bullying in Australian NICUs. The
preliminary results show that 16% (5 of 32 NICU registrars) of anonymous
respondents to a questionnaire reported that they had felt bullied. The
mean severity of bullying was 2.2 on a scale where 0 was no bullying and 5
was extremely severe bullying.
Any doctor new to a unit can feel uncomfortable in a situation where the
"usual ward policy" is different to what they have previously encountered.
We all need to support our junior colleagues, but the bottom line must
surely be to provide the best care of the babies: any doctors refusing to
do this should seriously consider whether they should be working in a
NICU.
Donna Gandini FRACP
Department of Neonatalogy, The Townsville Hospital, QLD 4814 Australia
References
(1) Patole S. Bullying in neonatal intensive care units: free for all. Arch
Dis Child Fetal Neonatal Ed 2002; 86: F68-70.
(2) Koh THHG, Koh TS. Harmony in the NICU. Arch Dis Child Fetal Neonatal Ed
2002; 86: F68-70.
There is considerable interest surrounding echocardiography on the
neonatal unit as illustrated by the discussion that has followed Dr.
Katumba's recent article.[1] Unfortunately, as neonatologists we have
often tended to rely on anecdotal evidence to support the view that
echocardiography is a useful tool with which to diagnose and monitor
cardiac function in a Neonatal Intensive Care Unit (NICU)....
There is considerable interest surrounding echocardiography on the
neonatal unit as illustrated by the discussion that has followed Dr.
Katumba's recent article.[1] Unfortunately, as neonatologists we have
often tended to rely on anecdotal evidence to support the view that
echocardiography is a useful tool with which to diagnose and monitor
cardiac function in a Neonatal Intensive Care Unit (NICU).
There is very little published data which has been obtained
prospectively and systematically to inform us about who performs
echocardiography on the neonatal unit, why and when such scans are
performed, the range of echocardiographic findings and how they influence
clinical management.[2] A related issue is the reliability of
echocardiography in the hands of neonatologists, who have an interest (but
usually no formal training)in neonatal echocardiography. We believe these
are areas worthy of systematic study and where we hope to provide some
objective data in the near future.
Further information is essential before we can confidently state that
echocardiography is a useful and reliable tool in the hands of
neonatologists.
References
(1) Jasper Katumba-Lunyenya. Neonatal/Infant echocardiography the non
- cardiologist: a personal practice, past present and future. Arch Dis
Child Fetal Neonatal Ed 2002: 86: F55-57.
(2) Evans N. Echocardiography in neonatal intensive care unit in
Australia and New Zealand. J Paediatr Child Health 2000;36,169-71.
It is gratifying to read the experiences of Drs Katumba and McNamara,
which mirror my own exactly. In Australia and New Zealand, 40% of NICUs
now have their primary echocardiography service provided by a
neonatologist[1]. Like Dr Katumba, these neonatologists all stress the
importance of working in close association with a Paediatric Cardiology
Service. This reflects a general shift, which is the move of...
It is gratifying to read the experiences of Drs Katumba and McNamara,
which mirror my own exactly. In Australia and New Zealand, 40% of NICUs
now have their primary echocardiography service provided by a
neonatologist[1]. Like Dr Katumba, these neonatologists all stress the
importance of working in close association with a Paediatric Cardiology
Service. This reflects a general shift, which is the move of ultrasound
beyond its traditional boundaries of being a consultative diagnostic tool
to being an acute 'coal face' diagnostic tool. While there is resistence to
this change from some quarters, neonatology is not the only specialty
where this is happening. For me it is difficult to imagine practicing
without immediate access to ultrasound.
From this position, John Thompson and colleague's dismissal of serial
echocardiography in NICU because there is no evidence it improves outcomes
seems surprising. Using such an argument we would cease doing chest xrays,
blood tests, head ultrasounds, monitoring blood pressure or even clinical
examination, none of which have been rigorously tested or shown to improve
outcomes. We do them because they give us diagnostic information. While
serial echocardiography has not been proven to improve outcomes, it is a
powerful diagnostic tool that has gone a long way in improving our
understanding of newborn disease processes. Work by our group has defined,
in large cohorts of very preterm babies, an abnormal transitional
haemodynamic that includes a period of significant systemic hypoperfusion
that is significantly related to IVH [2], hyperkalaemia[3], abnormal
development at 3 years [4] and mortality [7]. We have also shown both how
limited clinical signs are in detecting this [5,6,7] and how limited our
current circulatory support strategies are in treating this abnormal
haemodynamic[8]. And yes, we have also shown that this abnormal
haemodynamic is probably partly due to immature myocardial function and
its reduced ability to respond to increases in afterload (not yet
published but will be in 2002 North American SPR abstracts).
It is exactly because neonatologists are acquiring echocardiographic
skills that rigorous serial study has been possible. This in turn has
highlighted many misconceptions of traditional thinking about newborn
haemodynamics. Through this better understanding may lie the key to
prevention of adverse outcomes in the babies we care for.
References.
(1) Evans N. Echocardiography in neonatal intensive care unit in Australia
and New Zealand. J Paediatr Child Health 2000;36,169-71
(2) Kluckow M, Evans N. Low superior vena cava flow and intraventricular
haemorrhage in preterm infants. Arch Dis in Child 2000;82: F188-194.
(3) 3. Kluckow M, Evans N. Low systemic blood flow and hyperkalaemia. J
Pediatr
2001;139:227-232
(4) Kluckow M, Evans N. High pulmonary blood flow, the duct and pulmonary
haemorrhage. J Pediatr 2000;137:68-72
(5) Hunt R, Evans N, Kluckow M, Reiger I. Low early superior vena cava flow
and neurodevelopment at 3 years. Pediatr Res 2001;49:336A (abstr)
(6) Kluckow M, Evans N. The relationship between cardiac output and blood
pressure in preterm infants requiring mechanical ventilation. J Pediatr
1996;129:506-512.
(7) Osborn DA, Evans N, Kluckow M. Accuracy of capillary refill time and
blood pressure for detecting low systemic blood flow in preterm babies.
Pediatr Res 2001;49:376A (abstr)
(8) Skelton R, Evans NJ, Smythe J. A blinded comparison of clinical and
echocardiographic evaluation of the preterm infant for patent ductus
arteriosus. J Paediatr Child Health 1994;30:406-11.
(9) Osborn DA, Kluckow M, Evans N. Randomised trial of dobutamine vs
dopamine in preterm infants with low systemic blood flow. J Pediatr 2002,
in press.
I read with great interest the article of Fang et al, who
investigated the relationship between mesenteric response to feeding and
feeding tolerance in preterm infants [1]. In a comparable population, we
reported that the significant increase in velocity in the superior
mesenteric artery after a first feed given during the first week of life
was not influenced by perinatal acute asphyxia, gesta...
I read with great interest the article of Fang et al, who
investigated the relationship between mesenteric response to feeding and
feeding tolerance in preterm infants [1]. In a comparable population, we
reported that the significant increase in velocity in the superior
mesenteric artery after a first feed given during the first week of life
was not influenced by perinatal acute asphyxia, gestational age,
intrauterine growth retardation, early post-natal respiratory distress or
hypotension [2]. In our small cohort, good tolerance to enteral feeds
during the first weeks of life was associated with a greater rise in end
diastolic velocity, which is close to the authors' observation of a
positive correlation between early tolerance to enteral feeds and a lower
index of vascular resistance after the test feed. Two questions
nevertheless seem important: Is a single Doppler measurement of superior
mesenteric artery blood flow sufficient to determine when to feed a "high
risk" preterm infant? And which criteria define the "high risk" infant? As
mentioned by Martinussen et al. [3], preterm infants require a systemic
circulatory adaptation to allow postprandial mesenteric hyperemia, with an
increase in cardiac output and a decrease in blood pressure. The
circumstances associated with hemodynamic instability, as in sepsis, or
elevated baseline cardiac output, as in ductal steal, could thus
compromise the circulatory response to feeding and lead to intolerance. In
our population, we tested numerous biodemographic and clinical factors
suggested by previous research [4], but also a more than 30% increase in
mesenteric diastolic velocity 30 min after a test feed of 4 ml/kg of human
milk, for their relationship to feeding tolerance during the first three
weeks of life. This multilinear regression analysis revealed the
significant positive influence of antenatal steroids and the negative
influences of significant ductus arteriosus, nosocomial infection, and
prolonged ventilatory dependency. The result of the mesenteric profile
after the test feed, however, was not included in the final model. We thus
believe that a single examination of superior mesenteric artery blood flow
velocities after a first feed at the third postnatal day - as suggested by
the authors - is probably insufficient to predict mean term feeding
tolerance and should instead be integrated into a more complete evaluation
of the patient's hemodynamic status. We personally recommend serial
evaluations in cases of ductus persistence or reopening and before enteral
feeding resumption after significant gut disease.
Gilles Cambonie
Neonatal Intensive Care Unit, Hôpital Arnaud de Villeneuve, University Hospital of Montpellier, France.
References
(1) Fang S, Kempley ST, Gamsu HR. Prediction of early tolerance to enteral
feeding in preterm infants by measurement of superior mesenteric artery
blood flow velocity. Arch Dis Child Fetal Neonatal Ed 2001; 85: F42-5.
(2) Cambonie G, Luc F, Montoya F, Sarda P, Rieu D. Mesenteric blood flow in
premature infants. Pediatr Res 1996; 40: 522 (A 46).
(3) Martinussen M, Brubakk AM, Vik T, Yao AC. Mesenteric blood flow
velocity and its relation to transitional circulatory adaptation in
appropriate for gestational age preterm infants. Pediatr Res 1996; 39: 275
-80.
(4) Slagle TA, Gross SJ. Effect of early low-volume enteral substrate on
subsequent feeding tolerance in very low birth weight infants. J Pediatr
1988; 113: 526-31.
I would like to thank Dr Thomson and colleagues for their comments. I
need to clarify on an issue they picked upon which when quoted in
isolation gives the reader the wrong impression. They seem to suggest that
I am advising the reader that inappropriate referrals are “firmly refused”
out of hand. What I actually meant, if you read on, was that one should
refuse to see referrals from other colleagues w...
I would like to thank Dr Thomson and colleagues for their comments. I
need to clarify on an issue they picked upon which when quoted in
isolation gives the reader the wrong impression. They seem to suggest that
I am advising the reader that inappropriate referrals are “firmly refused”
out of hand. What I actually meant, if you read on, was that one should
refuse to see referrals from other colleagues which have not been properly
clinically assessed.
My colleagues have listened to me resulting in a dramatic drop in
numbers of innocent murmurs presenting to my clinic and to the two
outreach clinics run by two cardiologists, one from Oxford and the other
from the Brompton. They are, however, encouraged to refer for
echocardiography if in doubt.
I was a little disturbed by the statement made by Dr Thomson et al
that systolic dysfunction rarely causes hypotension in the neonate in
intensive care. I can not presume to comment on cause of hypotension in
bigger children in PICU, as I never scan this group of patients. There is,
however, no doubt that several authorities believe that poor myocardial
contractility together with "systemic steal" through the often silent
patent ductus arteriosus, and abnormal peripheral vasoregulation are the
three commonest contributors to hypotension in neonates especially the
extreme preterm during the first 24 to 72 hours of extrauterine life
[1-8]. Hypovolaemia, however, is the rarer cause of
hypotension in this setting. A D Gill and A M Weindling [2] recognised the
contribution of poor myocardial contractility to hypotension years ago.
There is a massive volume of authoritative literature to support the above
statements and the February 2001 issue of Seminars in Neonatology co-
edited by Nick Archer and Nick Evans covers this topic extensively as well
as providing a huge source of references. Dr Thomson et al do not give any
references to support his view and I am not personally aware, though I
stand to be corrected, of any such literature in the last few years.
Unlike in the adult and bigger child where it is easy to invasively
assess haemodynamic changes on the ICU, this is not as easily done in the
neonate and echocardiography provides a useful non-invasive tool for this
purpose on the NICU. The duct is also usually "silent" in the first three
to five days even when open and can only be diagnosed by echo. Recent
evidence suggests that ibuprofen is at least as effective as indomethacin
in closing the duct without the co-morbidity (decreased cerebral, renal
and gastrointestinal perfusion etc.) associated with indomethacin [9,10].
This would make medical closure of the duct much more acceptable even for
those paediatricians who have rightly so, hitherto, been worried about the
complications associated with indomethacin therapy.
If one accepts the fact that hypotension is associated with increased
morbidity and mortality [2] and that silent ducts can cause problems in
preterm neonates, then one can reasonably hope that "sequential
echocardiography"[7] during the first 72 hours, and later as necessary,
might reduce morbidity and mortality by improving assessment and
management of these problems.
Moreover Paediatricians and Neonatologists are already voting with
their feet and the Echo course at my tertiary centre is usually
oversubscribed by 100% because they are beginning to recognise usefulness
of echocardiography in neonatology.
I am pleased that the RCPCH SAC in Paediatric Cardiology is looking
at training paediatricians to develop the skills of cardiology but I
sincerely hope that the curriculum will include echocardiographic
assessment of the duct and hypotension in the sick preterm infant and its
impact on management. Not to include it will be a lost opportunity, which
I predict will only have to be redressed later because of the mounting
weight of evidence that echocardiography, is a very useful tool in this
setting.
References (1) Jasper Katumba-Lunyenya. Neonatal/Infant echocardiography the non-
cardiologist: a personal practice, past present and future. Arch Dis Child
Fetal Neonatal Ed 2002: 86: F55-57.
(2) AB Gill, AM Weinding. Echocardiographic assessment of cardiac
function in shocked very low birthweight infants. Arch Dis Child Fetal
Neonatal Ed 1993; 68: 17-21.
(3) Nick Evans. Diagnosis of patent Ductus arteriosus in the preterm
newborn. Arch Dis Child Fetal Neonatal Ed. 1993; 68: 58-63.
(4) Jon Skinner. Diagnosis of patent ductus arteriosus. Semin
Neonatology 2001; 6: 49-61.
(5) Evans N, Moorcroft J. Effect of patency of the ductus on blood
pressure in very preterm infants. Arch Dis Child 1992; 67: 1169-1173.
(6) David B Knight. The treatment of ductus arteriosus in preterm
infants. A review and overview of randomised trials. Semin Neonatal 2001;
6: 63-73.
(7) Martin Kluckow, Nick Evans. Low systemic blood flow in the preterm
infant. Semin Neonatal 2001; 6: 75-84.
(8) Istvan Seri. Circulatory support of the sick preterm infant. Semin
Neonatal 2001; 6: 85-95.
(9) B Van Overmeire et al. A comparison of Ibuprofen and Indomethacin
for closure of Patent Ductus Arteriosus. New England Journal of Medicine;
2000; 343:674-681.
(10) Jayesh Patel, Idris Roberts, Dennis Azzopardi, et al. Randomised
Double – Blind Controlled Trial Comparing the Effects of Ibuprofen with
Indomethacin on Cerebral Haemodynamics in Preterm Infants with Patent
Ductus Arteriousus. Paediatric Research 2000; 47: 36-42.
We read the article by Kumar et al[1] with interest especially in light
of the changing profiles of NICU practices as applicable to a developing
nation with limited resources and lack of uniform parameters for
antibiotic usage, resulting in the emergence of drug resistant strains.
However, the utility of a rapid diagnostic system has to be viewed in the
light of its universal applicability. The cost of s...
We read the article by Kumar et al[1] with interest especially in light
of the changing profiles of NICU practices as applicable to a developing
nation with limited resources and lack of uniform parameters for
antibiotic usage, resulting in the emergence of drug resistant strains.
However, the utility of a rapid diagnostic system has to be viewed in the
light of its universal applicability. The cost of setup and subsequent
maintenance of a rapid culture system like BacT/Alert needs to be looked
into vis a vis the traditional culture methodologies, which still are high
yield relative to their low cost and results are available within 48-72
hours. Appearance of a growth itself can be taken as a decision tool for
continuation of antibiotics pending the subculturing process in an
appropriate clinical scenario. Automation has its advantages but need for
calibration and standardization should not be ignored. Possibilities of
false positive signals do remain and in a scenario of frequent power
failures the performance of such a system may be far from ideal and can
lead to potentially disastrous decisions.
Authors emphasise that the clinical status of the neonate still
remains the most important factor in deciding the management of neonatal
sepsis and therefore, a symptomatic neonate will continue to get
antibiotics even in the absence of laboratory support, for a duration, if
the clinical condition so demands. In asymptomatic neonates, there is need
to have more clear guidelines about the duration of therapy once the
antibiotics were started initially, may be based upon either
symptomatology or high perinatal risk scores. In this study, the authors
have not spelt out the clinical or laboratory criteria utilized after
negative blood culture results at 36 hours, so as to consider presence or
absence of sepsis and to justify continuation or discontinuation of
antibiotics beyond 36 hours, awaiting the final culture report at 72
hours. It will be pertinent for the practice that between 36 and 72 hours
period, the decisions about antibiotic therapy should not be based on
negative culture test at 36 hours alone but must additionally utilize the
rapid diagnostic tests (RDT), like use of IL-6 and C-reactive protein or
TNF alpha. These RDTs have good cumulative accuracies for the diagnosis
and exclusion of sepsis. [2,3] RDTs negativity after 36 hours, in culture
negatives will give additional strength to decision of stopping of
antibiotics. If these RDTs remain positive at 36 hours in culture
negatives, then it will be justified to continue antibiotics till the
final blood culture report becomes available at 72 hours and decision
about antibiotic continuation taken accordingly. Therefore, it will be
interesting to have information from the current study, on clinical
condition and RDTs status of neonates, after obtaining 36 hours report of
culture till 72 hours of life and final decisions about use of
antibiotics. A rapid diagnostic blood culture system is likely to be most
relevant in a clinical scenario of high perinatal sepsis risk score
dictating use of antibiotics [4], asymptomatic neonate and with early
negative RDT. An early negative blood culture result at 36 hours then
could be the gold standard proof for absence of sepsis and mandating
discontinuation of antibiotics in this subset of neonates.
Lastly the study in its retrospective design has limitations of
applicability. There appears to be a bias towards LBW/prematures in the
study, as data regarding term/AGA babies is not available in this study.
The definitive pathogens in term babies are likely to be different and
there may not be predominance of coagulase negative staphylococcus in
them.
References:
(1) Kumar Y, Qunibi M, Neal TJ, Yoxall CW Time to positivity of neonatal
blood cultures. Arch Dis Child Fetal Neonatal Ed 2001 Nov;85(3):F182-6
(2) Ng PC, Cheng SH, Chui KM, Fok TF, Wong MY, Wong W, Wong RP, Cheung
KL.Diagnosis of late onset neonatal sepsis with cytokines, adhesion
molecule, and C-reactive protein in preterm very low birthweight infants.
Arch Dis Child Fetal Neonatal Ed 1997 Nov;77(3):F221-7)
(3) Philip AG, Mills PC Use of C-reactive protein in minimizing antibiotic
exposure: experience with infants initially admitted to a well-baby
nursery. Pediatrics 2000 Jul;106(1):E4
(4) Singh M, Narang A, Bhakoo ON Predictive perinatal score in the
diagnosis of neonatal sepsis J Trop Pediatr 1994 Dec;40(6):365-8
Dr Katumba-Lunyenya rightly recognises that management of common
cardiological problems in neonates is beyond the resource provision for
congenital heart disease specialists in the UK. The author also realises
that along with the echocardiographic skills come the “innappropriate
referrals”. Sadly there is no doubt that the increased reliance on
investigations of all types (particularly the echocardi...
Dr Katumba-Lunyenya rightly recognises that management of common
cardiological problems in neonates is beyond the resource provision for
congenital heart disease specialists in the UK. The author also realises
that along with the echocardiographic skills come the “innappropriate
referrals”. Sadly there is no doubt that the increased reliance on
investigations of all types (particularly the echocardiogram) has been
mirrored by a decline in cardiac clinical skills amongst paediatricians of
all grades.
In some of our outpatient clinics (Yorkshire heart centre) over 50% of new
referrals from specialist paediatric staff are innocent murmurs. Our data
support the view that these referrals (described as innappropriate by the
author) are increasing from both District and Teaching hospitals and that
a high proportion come from junior doctors, the patient having been
examined only once (during an intercurrent illness) and often not seen by
a consultant. If we were to follow the authors advice we would be “firmly
refusing” hundreds of referrals. Similar problems arise on neonatal
intensive care units, and whilst the echocardiogram can be a powerful
diagnostic tool in this setting, there is no evidence base to suggest that
serial echocardiography improves outcome in neonates. Systolic dysfunction
is rarely a cause of hypotension in children or neonates on intensive care
units and ultrasound is of very limited value in the assessment of
ventricular filling in this setting.
The RCP SAC in Paediatric Cardiology recognises the implications of
increasing demands on paediatric cardiac services. With the Royal College
of Paediatrics and Child Health a working party has been established to
develop a curriculum of training for paediatricians with a special
expertise in paediatric cardiology to increase the opportunities for
paediatricians to develop clinical skills in cardiology (of which
echocardiography is just one) relevant to the management of these
patients.
Dr John Thomson
Specialist registrar and trainee representative SAC Paediatric Cardiology
Dr John Gibbs
Consultant paediatric cardiologist and secretary SAC Paediatric Cardiology
Both Yorkshire heart centre, Leeds general infirmary NHS Trust.
Dr Sue Hobbins
Consultant Paediatrician with special expertise in Paediatric Cardiology
and RCPCH representative on SAC in paediatric cardiology.
Bromley Hospitals NHS Trust.
Me thinks Professor Sulyok doth protest too much. His early, pioneering work on electrolyte balance in the newborn is well known (and extensively cited in an earlier review of the subject co-authored by myself.[1] In this, inter alia, his study of the effect of salt supplementation on the renin-angiotensin-aldosterone system [2] is quoted in support of the hypothesis that hyponatraemia in premature infant...
Dear Editor
In their study on time to positivity of neonatal blood cultures, Kumar et al[1] conclude that a period of 36 hours is sufficient to exclude sepsis in otherwise well neonates. They documented that the negative predictive value of neonatal blood cultures at 36 hours is 98% for definite or possible pathogenic bacteria. This is also true in our experience using a different automated blood culture system...
Dear Editor
Dr da Costa et al, and Dr Gatrad in his accompanying commentary [Arch Dis Child Fetal Neonatal Ed 2002;86:F115-9], are mistaken in drawing convulsions about Muslim families in relation to ‘do not resuscitate orders’. Gatrad suggests doctors should receive training in ethical issues of other cultures. Firstly, it is impossible to know the religious or historical or personal background of every parent....
NB This letter is also in response to Dr Koh's letter on the same topic (click link for access):
http://adc.bmjjournals.com/cgi/content/full/fetalneonatal;86/1/F68-a
Dear Editor
The letter written by Patole [1] on bullying in neonatal intensive care units (NICU) is misleading if it is meant to refer to the Neonatal Intensive Care Unit at The Townsville Hospital. In two years working as Senior...
Dear Editor,
There is considerable interest surrounding echocardiography on the neonatal unit as illustrated by the discussion that has followed Dr. Katumba's recent article.[1] Unfortunately, as neonatologists we have often tended to rely on anecdotal evidence to support the view that echocardiography is a useful tool with which to diagnose and monitor cardiac function in a Neonatal Intensive Care Unit (NICU)....
Dear Editor
It is gratifying to read the experiences of Drs Katumba and McNamara, which mirror my own exactly. In Australia and New Zealand, 40% of NICUs now have their primary echocardiography service provided by a neonatologist[1]. Like Dr Katumba, these neonatologists all stress the importance of working in close association with a Paediatric Cardiology Service. This reflects a general shift, which is the move of...
Dear Editor
I read with great interest the article of Fang et al, who investigated the relationship between mesenteric response to feeding and feeding tolerance in preterm infants [1]. In a comparable population, we reported that the significant increase in velocity in the superior mesenteric artery after a first feed given during the first week of life was not influenced by perinatal acute asphyxia, gesta...
Dear Editor
I would like to thank Dr Thomson and colleagues for their comments. I need to clarify on an issue they picked upon which when quoted in isolation gives the reader the wrong impression. They seem to suggest that I am advising the reader that inappropriate referrals are “firmly refused” out of hand. What I actually meant, if you read on, was that one should refuse to see referrals from other colleagues w...
Dear Editor
We read the article by Kumar et al[1] with interest especially in light of the changing profiles of NICU practices as applicable to a developing nation with limited resources and lack of uniform parameters for antibiotic usage, resulting in the emergence of drug resistant strains. However, the utility of a rapid diagnostic system has to be viewed in the light of its universal applicability. The cost of s...
Dear Editor
Dr Katumba-Lunyenya rightly recognises that management of common cardiological problems in neonates is beyond the resource provision for congenital heart disease specialists in the UK. The author also realises that along with the echocardiographic skills come the “innappropriate referrals”. Sadly there is no doubt that the increased reliance on investigations of all types (particularly the echocardi...
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