I suggest breast feeding increases infant DHEA which positively
affects growth and development. Please read "DHEA is the Reason Breast
Milk is Beneficial," at: http://anthropogeny.com/DHEA%20Breast%20Milk.htm
We thank Dr. Johnson for his interest in our paper [1] and for the
opportunity to discuss methods for modelling child growth. Many methods
for modelling repeated measures data are available, and the strengths and
limitations of each method will depend on many factors, including the
specific research question of interest and the structure of the data being
analysed.[2] In our analysis, we used linear spline multilevel mode...
We thank Dr. Johnson for his interest in our paper [1] and for the
opportunity to discuss methods for modelling child growth. Many methods
for modelling repeated measures data are available, and the strengths and
limitations of each method will depend on many factors, including the
specific research question of interest and the structure of the data being
analysed.[2] In our analysis, we used linear spline multilevel models.
Such models divide age into separate 'pieces' joined with knot points, and
model a different linear slope between each pair of knots. Individual-
level random effects allow individuals to differ in both starting size
(birth length or weight) and in their rate of growth in each period of
childhood. Clearly, such a piecewise linear model is an approximation of
the true complex underlying growth pattern. However, a key advantage of
using linear splines to model infant and child growth is that they are
easy to interpret. As well as being a useful way of creating interpretable
summaries of growth trajectories, the linear spline approach provided good
fit to our data, for all ethnic and sex groups, as seen in Supplementary
web table 2 of our original paper.
Selection of knot points for linear spline models is an important
issue. However, Dr. Johnson is incorrect when he states that we used the
same knot points that had been derived from the Avon Longitudinal Study of
Parents and Children (ALSPAC) data. As reported in the statistical
analysis section of our paper, [1] we considered a series of models with
knot points at different ages, and selected the best fitting models for
the Born in Bradford data. These knot points were slightly different to
those used in the ALSPAC study. However, it is interesting to note that
this methodology has now been employed in several cohorts in varied
geographical settings and with different ethnic and socioeconomic
composition and that in each case, similar knot points that best fit the
data in these different studies have been identified.[3-8] The fact that
best-fitting models using data from very different populations have such
similar knot points gives some biological credibility to the periods of
growth identified by these models.
In the Born in Bradford cohort we had insufficient data in the first
month of life to model neonatal weight loss. When these methods are
applied to datasets with a greater number of measurements in early life,
it is possible to model neonatal weight loss. For example in the
Generation XXI cohort, based in Porto, Portugal, a median of ten growth
measures are available for each child within the first few years of life,
with almost all children having multiple growth measurements recorded in
the first months of life. In this cohort, linear spline multilevel models
with knot points at 10 days, 3 months and 1 year fit the data well.[8]
Dr. Johnson suggests that individual knot points should have been
used in our study. In contrast to our analyses, such models allow the age
of change points within growth trajectories to vary between individuals.
Allowing for individual-specific knot points may result in better fit of
the statistical model to the data.[9] But this increased model fit comes
at the cost of complexity and interpretability. The timing of knot points
is likely to be related to the rate of change before and after that knot
point, and thus these quantities would need to be interpreted carefully.
The potential added benefits of using this approach to address our
question of ethnic differences in growth depend on two main factors: how
variable knot points are likely to be between individuals, and whether the
timing of individual-specific knot points is of interest in its own right.
We do not feel that either of these actually support the use of this
method to address the research question we were answering. Individual
variation in, for example, the timing of puberty onset or the timing of
cognitive decline in older age [10] is likely to be considerably greater
than individual variation in the timing of changes in growth velocity in
infancy and early childhood; therefore models incorporating individual-
specific knot points may be more useful in the former situations than in
the latter. Likewise, our research question concerned describing ethnic
differences in rates of growth and was not concerned with ethnic
differences in the timing of features of early growth. Such an approach
would be useful when the research question centres on the timing of change
and how this timing relates to earlier exposures or later outcomes, for
example, when assessing whether age at puberty is associated with later
cardiovascular health, one would need to estimate individual age at onset
of puberty rather than assuming that this was constant across the
population.
We once again thank Dr. Johnson for his interest in our paper. Whilst
we recognise that linear spline models represent a simplification of the
true underlying growth process, we feel that they are a suitable
compromise between model fit, which was good in our study, and
interpretability. Examination of growth using different models is
important for triangulation, and different methods will be relevant for
different research questions.
Reference List
1. Fairley L, Petherick ES, Howe LD, Tilling K, Cameron N, Lawlor DA,
et al. Describing differences in weight and length growth trajectories
between white and Pakistani infants in the UK: analysis of the Born in
Bradford birth cohort study using multilevel linear spline models. Arch
Dis Child 2013,98:274-279.
2. Hauspie R, Cameron N, Molinari L. Methods in Human Growth
Research: Cambridge University Press; 2004.
3. Howe LD, Tilling K, Galobardes B, Smith GD, Gunnell D, Lawlor DA.
Socioeconomic differences in childhood growth trajectories: at what age do
height inequalities emerge? J.Epidemiol.Community Health 2012,66:143-148.
4. Paternoster L, Howe LD, Tilling K, Weedon MN, Freathy RM, Frayling
TM, et al. Adult height variants affect birth length and growth rate in
children. Hum.Mol.Genet. 2011,20:4069-4075.
5. Matijasevich A, Howe LD, Tilling K, Santos IS, Barros AJ, Lawlor
DA. Maternal education inequalities in height growth rates in early
childhood: 2004 Pelotas birth cohort study. Paediatr.Perinat.Epidemiol.
2012,26:236-249.
6. Tilling K, Davies N, Windmeijer F, Kramer MS, Bogdanovich N,
Matush L, et al. Is infant weight associated with childhood blood
pressure? Analysis of the Promotion of Breastfeeding Intervention Trial
(PROBIT) cohort. Int.J.Epidemiol. 2011,40:1227-1237.
7. Tilling K, Davies NM, Nicoli E, Ben-Shlomo Y, Kramer MS, Patel R,
et al. Associations of growth trajectories in infancy and early childhood
with later childhood outcomes. Am.J.Clin.Nutr. 2011,94:1808S-1813S.
8. Howe LD. Individual trajectories of childhood growth in five
cohorts: the application of linear spline multi-level models. In:
EUCCONET/ Society for Longitudinal and Life Course Studies. Paris; 2012.
9. Bellera CA, Hanley JA, Joseph L, Albertsen PC. Hierarchical
changepoint models for biochemical markers illustrated by tracking
postradiotherapy prostate-specific antigen series in men with prostate
cancer. Ann Epidemiol 2008,18:270-282.
10. van den Hout A, Muniz-Terrera G, Matthews FE. Change point models
for cognitive tests using semi-parametric maximum likelihood. Comput Stat
Data Anal 2013,57:684-698.
Dr Webb's article highlights the fact that ADHD can be considered as
a behavioural problem caused by many different aetiologies, including
significan physical and emotional abuse. She identifies that the sort of
abuse that triggers this behaviour is often longstanding and at a level
that becomes tolerated by statutory services who are usually quick to
intervene when there is physical harm, but allow emotional and social...
Dr Webb's article highlights the fact that ADHD can be considered as
a behavioural problem caused by many different aetiologies, including
significan physical and emotional abuse. She identifies that the sort of
abuse that triggers this behaviour is often longstanding and at a level
that becomes tolerated by statutory services who are usually quick to
intervene when there is physical harm, but allow emotional and social
problems to fester.
It raises the question as to what is an appropriate safeguarding
response to children presenting with ADHD? A child presenting with a
subdural haemorrhage or unexplained fracture would have some level of
safeguarding investigation performed - unless there was a clear non
abusive history of trauma. Minimally this would be at a hospital level,
but more likely escalated to police and social services.
Given the high incidence of disturbing and abusive behaviours in
families with ADHD, it can be deduced that the child's condition is a
result of this in much the same way that a subdural haemorrhage may be
caused by shaking. Both conditions carry a guarded long term prognosis and
are therefore manifestations of 'significant harm.'
It seems sensible to suggest that when making a diagnosis of ADHD in
a child, serious consideration should be given to referring the family for
a multiagency safeguarding assessment.
Dear Ed
Gill [1] and Powell [2] state there is little data on delivery of
unscheduled care. We would like to share
our learning.
To improve paediatric training in primary care one of us (SC) has
worked with Advanced Life Support
Group (ALSG) led by SW and piloted a, "Poorly Child Pathway Course." This
one day course deals
with the most common acute childhood presentations and uses a traffic
light system (gree...
Dear Ed
Gill [1] and Powell [2] state there is little data on delivery of
unscheduled care. We would like to share
our learning.
To improve paediatric training in primary care one of us (SC) has
worked with Advanced Life Support
Group (ALSG) led by SW and piloted a, "Poorly Child Pathway Course." This
one day course deals
with the most common acute childhood presentations and uses a traffic
light system (green, amber,
red) to classify patients. It aims to improve the management of children
presenting to Urgent Care and
Out of Hours and communication between primary and secondary care.
23 candidates were taught by 8 faculty. Candidate and Faculty
feedback is ongoing, early results
show: 80% agreed that a one day course worked well; confidence improved
from 2.7/4 to
3.8/4. Primary Care facilities do not have the facility to review patients
so hospitals see all amber
patients
The second intervention was to pilot a, "Front of House," (FoH) model
of care where children
were seen and assessed by either a consultant paediatrician, paediatric
middle grade or Advanced
Nurse Practitioner Students (APNPs) prior to admission. There are two 24
hour paediatric
units within CDDFT separated by 22 miles, University Hospital North Durham
(UHND) and Darlington
Memorial Hospital (DMH). The pilot ran at DMH over a 3 week period between
5th to 23rd November,
2013 on Mondays to Fridays 9:00 to 21:00. There was insufficient staff to
run this model at weekends.
During November there were 391 admissions under 18 years of age
compared to 406
in November 2012. The data is not scientific. Considering successive 8%
annual increases in
admissions it suggests a decrease in admissions.
We plan to perform a 6 month, "trial," at UHND using the system 7
days a week with consultants
triaging calls.
References
1. Gill PJ, Goldacre MJ, Mant D et al. Increase in Emergency
Admissions to Hospital for Children aged under 15 in Emgland, 199-2010:
National Database Analysis. Arch. Dis Child 2013; 98: 328-334
2. Powell C Do we need to change the way we deliver unscheduled care?
Arch. Dis Child 2013; 98: 319-320
With sincere thanks to the faculty of the pilot Poorly Child Pathway
Course:
Prof. Peter Driscoll (IDP)
Dr. Martin Samuels (Stoke-on-Trent)
Paul Lattimer (CDDFT)
Dr Leigh Simmonds (CDDFT)
Dr John Holmes (CDDFT)
Dr Barbara Phillips (IDP)
Dr David Ratcliffe (Manchster)
and to our APNPs:
Lisa German-Phillips
Amanda Dunn
Susie Watson
Shona Sangster
Meg Davies
Cheryl Peart
We have read with interest the paper by Sayal et al. concerning a
cohort of 11-year-old children prenatally exposed to alcohol and the major
conclusion that light drinking in pregnancy does not appear to be
associated with clinically important adverse effects for mental health and
academic outcomes at the age of 11 years.
This broad epidemiological study has several problems related to the...
We have read with interest the paper by Sayal et al. concerning a
cohort of 11-year-old children prenatally exposed to alcohol and the major
conclusion that light drinking in pregnancy does not appear to be
associated with clinically important adverse effects for mental health and
academic outcomes at the age of 11 years.
This broad epidemiological study has several problems related to the
analysis of data and to the risk assumption. First of all, it has been
demonstrated that questionnaires about the blame-attributing question of
alcohol consumption during pregnancy are not reliable, because women do
not tell the truth or because they are not aware about real alcohol
consumption. (1) As a consequence, the division of the groups of women
into various drinking levels cannot be considered reliable, which in turn,
makes it impossible to draw conclusions from the outcomes of tests on the
children. (1,2) Thus human observational studies must be based on
objective measurements of prenatal alcohol exposure, that is, based on
alcohol biomarkers in alternative matrices. (1,2)
There is clear evidence from animal studies and from human clinical
observation that prenatal exposure to alcohol has deleterious effects,
even in low doses, specifically on neurodevelopmental aspects. Clearer
answers on the effects of alcohol on humans are to be expected from
several currently on-going follow-up studies of newborns whose exposure
was measured based on meconium alcohol biomarkers. (3,4)
However, the most important problem of this paper is the non
acceptable risk assumption. It is not responsible to state that
"occasional light drinking does not appear to be associated with adverse
mental health or academic consequences at the age of 11 years". There HAVE
TO be sure that there is no risk at all; if not, it is mandatory to
recommend not to drink during pregnancy. Conversely to the authors'
conclusion, the most "advanced" advice for women is not to drink alcohol
during pregnancy. As everybody knows, lack of evidence is not the same as
evidence of absence, and in this case, no evidence of harm does not mean
evidence of no harm. (5)
Garcia-Algar O1,2, Diane Black2, Consuelo Guerri2,3, Simona
Pichini2,4
1 URIE, Institut Hospital del Mar d'Investigacions M?diques (IMIM),
Barcelona, Spain
2 European FASD Alliance, The Nederlands
3 Department of Therapeutic Research and Medicines Evaluation, Istituto
Superiore di Sanit?, Rome, Italy
4 Centro de Investigaci?n Pr?ncipe Felipe, Valencia, Spain
References
1. Manich A, Velasco M, Joya X, Garc?a-Lara NR, Pichini S, Vall O,
Garc?a-Algar O. [Validity of a maternal alcohol consumption questionnaire
in detecting prenatal exposure]. An Pediatr (Barc) 2012;76:324-328.
2. Pichini S, Marchei E, Vagnarelli F, Tarani L, Raimondi F, Maffucci R,
et al. Assessment of prenatal exposure to ethanol by meconium analysis:
results of an Italian multicenter study. Alcohol Clin Exp Res 2012;36:417-
424.
3. Garcia-Algar O, Kulaga V, Gareri J, Koren G, Vall O, Zuccaro P,
Pacifici R, Pichini S. Alarming prevalence of fetal alcohol exposure in a
Mediterranean city. Ther Drug Monit 2008;30:249-254.
4. Valenzuela CF, Morton RA, Diaz MR, Topper L. Does moderate drinking
harm the fetal brain? Insights from animal models. Trends Neurosci
2012;35:284-92.
5. Garcia-Algar O, Black D, Guerri C, Pichini S. The effect of different
alcohol drinking patterns in early to mid-pregnancy. BJOG 2012;119:1670-1.
We read Ladhani and Ramsay's editorial with great interest. Whilst we
agree on the need for the delivery of a completed course of Hepatitis B
vaccinations in infants of high-risk mothers where the fourth vaccination
is administration by their first birthday, in order to improve uptake of
vaccines it is essential to recognise factors preventing this occurring.
Firstly, Hepatitis B positive mothers diagnosed in an...
We read Ladhani and Ramsay's editorial with great interest. Whilst we
agree on the need for the delivery of a completed course of Hepatitis B
vaccinations in infants of high-risk mothers where the fourth vaccination
is administration by their first birthday, in order to improve uptake of
vaccines it is essential to recognise factors preventing this occurring.
Firstly, Hepatitis B positive mothers diagnosed in antenatal services
may give birth in a labour unit outside of their local area due to bed
pressures and newborns may not receive their first vaccination. This
should, however, be limited by the use of patient-held maternity records.
The initial Hepatitis B vaccination is often administered by
maternity or neonatal paediatric staff under a hospital doctor
prescription. Subsequent vaccines are currently offered by a variety of
healthcare professionals such as general practitioners (GP) or community
paediatricians. Yates et al[1] showed a high level of participation at the
first vaccination but large numbers of infants did not have follow-up
vaccines. Reasons for this may include poor transfer of information and
clinical records between providers. Also, the administration of infant
Hepatitis B vaccinations does not result in item of service payments for
GPs and as such GP may be less likely to offer follow up vaccinations.
Similarly, acquisition of vaccines, blood test sampling, sample handling
practices and pathology systems may vary among GP practices, thus posing
additional barriers to the completion of vaccination schedules and
serological testing.
In the North London Borough of Enfield, a number of children under
the age of 2 years old move in and out of area making follow-up more
challenging. However, in 2004 in this borough, 80% of all high-risk
neonates of Hepatitis B positive mothers registered at Chase Farm Hospital
during antenatal testing received the full vaccination course and
serology[2]. This success has been attributed to the use of a named
clinical lead conducting an integrated immunisation clinic with a clinic
nurse. The team would recall and follow up patients to offer immunisation
and serological testing while considering migration, language and access
barriers. In a resource-limited health system such immunisation clinics
may not be feasible. Universal vaccination of children with Hepatitis B
vaccines is not practical or more effective than a targeted approach[3].
Therefore, we would recommend that follow-up Hepatitis B vaccinations and
serology are performed by incentivised GPs as a new 'item of service'
payment.
1. Yates TA, Paranthaman K, Yu L-M, et al. UK vaccination schedule:
persistence of immunity to hepatitis B in children vaccinated after
perinatal exposure. Arch Dis Child 2013;98:429-33.
2. Giroudon I. Immunization Coverage in Infants at Risk of Perinatal
Transmission of Hepatitis B: A London Study (LANSSG). HPA London Regional
Epidemiology Unit. 2008.
3. Balogum MA, Parry JV, Mutton K, et al. Hepatitis B virus transmission
in pre-adolescent schoolchildren in four multi-ethnic areas of England.
Epidemiol Infect 2013; 141(5):916-25
Thank you for your response to our research 'The agreement of
fingertip and sternum capillary refill time (CRT) in children'
We agree that there is a lack of gold standard for assessing tissue
perfusion in a simple and timely manner and continue to extrapolate that
in shock, blood is usually diverted from the skin in an attempt to perfuse
vital organs. Current practice and guidance assumes that CRT is a
reflecti...
Thank you for your response to our research 'The agreement of
fingertip and sternum capillary refill time (CRT) in children'
We agree that there is a lack of gold standard for assessing tissue
perfusion in a simple and timely manner and continue to extrapolate that
in shock, blood is usually diverted from the skin in an attempt to perfuse
vital organs. Current practice and guidance assumes that CRT is a
reflection of this (1-7).
We were not expecting to find fingertip CRT to be faster than sternum CRT,
although we did not find it strange. We agree and also suspect that
different sites have different refill times because of the complex and
intricate relationships involved, which are not practical or possible to
record prior to carrying out the CRT (such as arteriolar resistance,
venular resistance etc. as discussed in Carcillo (1)). There is a
substantial amount of research in CRT in vascular medicine which we
decided not to include in our literature review prior to this study,
although our findings might indicate it would be more appropriate to
examine this area in more detail. We do know that the fingertip pulp is
rich in arterio-venous anastomoses which may explain why it had the
quickest CRT and that vascular resistance is increased in peripheral beds
and this may explain why it also had the slowest CRT.
We agree that there needs to be standardisation of the technique,
greater awareness of CRT limitations and it should be analysed in
conjunction with other haemodynamic markers. We suggested that guidance
provided by the Resuscitation Council (RC) (2-4), amongst others, be
reviewed for exactly these reasons. The RC highlight CRT as one of the
five parameters to observe when examining circulation, giving it equal
weighting to heart rate, pulse volume, blood pressure and end organ
perfusion status. The RC guidance does advise to consider CRT with other
cardiovascular signs but importantly does not consider the fingertip site
or variables such as inter and intra observer reliability and skin colour.
Carcillo's editorial is interesting; however this purposive review is
not balanced or systematic and does not provide a comprehensive overview
of the literature relating to CRT. Interestingly although Carcillo is
discussing sick children we are informed that CRT is age dependant and
rightly references the study that discovered this in 1988, there is no
evidence that tells us otherwise, yet we can find no guidance by the RC or
other group that utilises an age dependant model, why is that?
Our study did not set out to examine the usefulness of the test, but
led us to question the way CRT is conducted in current clinical practice.
In an era where we try to practice evidence based medicine, if this test
is recommended for use in practice (something our research cannot answer)
then we have a duty to generate the evidence to support the way in which
it is conduced.
1. Carcillo JA. Capillary refill time is a very useful clinical
signin early recognition and treatment of very sick children. Editorial on
Pediatr Crit Care Med 2012; 13:136 -140
2. Resuscitation Council. Medical Emergencies and Resucitation--
Standards for clinical
practice and training for dental practitioners and dental care
professionals in
general dental practice. http://www.resus.org.uk/pages/MEdental.pdf
(accessed May
2013):24.
3. Resuscitation Council. European paediatric life support (EPLS).
3rd edn. London:
4. Resuscitation Council 2011:12. Resuscitation Council. A systematic
approach to the acutely ill patient, adapted from the ALERTTM.
http://www.resus.org.uk/pages/alsABCDE.htm (accessed May 2013).
5. Jevon P. Measuring capillary refill time. Nurs Times 2007;103:26-
7.
6. Lima A, Jansen TC, Van Bommel J, et al. The prognostic value of
the subjective assessment of peripheral perfusion in critically ill
patients. Crit Care Med 2009;37:934-8.
7. Graham C, Parke T. Critical care in the emergency department:
shock and circulatory support. Emerg Med J 2005;22:17-21.
We are grateful to Dr Ladhani and Dr Ramsay [1] for their thoughtful
editorial that accompanied the publication of our paper [2]. We would
agree that, despite discrepant observational data in the UK regarding the
waning of antibody titres [2, 3], there is now a large body of evidence
[4] demonstrating that, even where antibody titres have waned, booster
doses are not required if an adequate primary schedule has been comp...
We are grateful to Dr Ladhani and Dr Ramsay [1] for their thoughtful
editorial that accompanied the publication of our paper [2]. We would
agree that, despite discrepant observational data in the UK regarding the
waning of antibody titres [2, 3], there is now a large body of evidence
[4] demonstrating that, even where antibody titres have waned, booster
doses are not required if an adequate primary schedule has been completed.
As discussed in the editorial, the pragmatic priority is to ensure
that all children complete the course and receive at least one further
dose after their initial (accelerated) schedule at 0, 1, 2 months.
Routine immunisation visits are a convenient time to do this, and the
pre-school booster presents one such opportunity. However, as Dr Ladhani
and Dr Ramsay have noted elsewhere, almost all UK children diagnosed with
chronic hepatitis B infection acquire this through vertical transmission
[5]. Having a named clinician responsible for delivery of the 0, 1, 2
month schedule can improve its delivery , and the 12 month routine vaccine
visit is more timely than the pre-school booster for ensuring its
completion.
1. Ladhani SN, Ramsay ME. The importance of a preschool booster for
children born to hepatitis B-positive mothers. Arch Dis Child. 2013; 98:
395-396.
2. Yates TA, Paranthaman K, Yu LM, et al. UK vaccination schedule:
persistence of immunity to hepatitis B in children vaccinated after
perinatal exposure. Arch Dis Child. 2013; 98: 429-433.
3. Boxall EH, A Sira J, El-Shuhkri N, et al. Long-term persistence of
immunity to hepatitis B after vaccination during infancy in a country
where endemicity is low. J Infect Dis. 2004; 190(7): 1264-9.
4. Leuridan E, Van Damme P. Hepatitis B and the need for a booster dose.
Clin Infect Dis. 2011; 53(1): 68-75.
5. Flood J, Amirthalingam G, Ramsay ME, et al. The diagnosis of chronic
Hepatitis B infection among children born in England after introduction of
universal antenatal HBV screening programme. Poster presented at the
European Society of Paediatric Infectious Disease Meeting, The Hague, June
2011. http://www.kenes.com/ espid2011/cd/pdf/P774.pdf.
Conflict of Interest:
Our study was supported by the NIHR Oxford Biomedical Research Centre and GlaxoSmithKline Biologicals. SL has undertaken paid work for vaccine manufacturers for provision of travel health training and attendance at advisory group meetings. AJP and MDS have conducted clinical trials on behalf of Oxford University sponsored by manufacturers of vaccines. AJP and MDS do not accept any personal payments from vaccine manufacturers: grants for support of educational activities are paid to an educational/administrative fund held by the Department of Paediatrics, Oxford University. MDS has received support from vaccine manufacturers to attend academic conferences. ED, SBW, SJH, KP and TAY declare no conflicts of interest besides funding received for the study.
We read with great interest the article on capillary refill time
(CRT) in children. Crook J and Taylor RM have carried out a simple and yet
very relevant study on CRT in children.CRT is almost universally checked
by child care providers particularly in emergency room or intensive care
setting and is taken as a surrogate of the perfusion status. However, two
issues have plagued this simple bedside te...
We read with great interest the article on capillary refill time
(CRT) in children. Crook J and Taylor RM have carried out a simple and yet
very relevant study on CRT in children.CRT is almost universally checked
by child care providers particularly in emergency room or intensive care
setting and is taken as a surrogate of the perfusion status. However, two
issues have plagued this simple bedside test:
(i) There seems to be no uniformity in the way this test is carried
out across the world. We recently published a letter to editor (1)
describing the variations in eliciting CRT amongst the various standard
texts and references. After analysis of all the references, it seemed
prudent to follow the Pediatric advanced life support(PALS )guideline for
CRT in children (finger tip) and the WHO guideline for CRT in young
infants (finger tip and sternum) with a pressure application of at least
3 seconds. There continue to be issues with eliciting CRT from the
peripheries in neonates (2).In the current article ,the authors have
rightly suggested a uniform practice for assessing CRT though it wasn't in
the purview of their study.
(ii) There have been various studies questioning the utility of CRT
.Even the APLS manual suggests use of caution in interpreting CRT as a
standalone measure of shock. Another recent article suggests poor inter-
rater reliability and poor correlation with cardiac output in non-acutely
ill children (3).The confusion with respect to studies on CRT perhaps
stems from the lack of a simple gold standard for assessing perfusion
status of the tissues. It could be the pulse pressure, skin temperature
gradient, central venous oxygen saturations (ScVO2), lactate , near infra
red spectroscopy (NIRS) etc or a mixture of such variables. It is also
important to remember that in an attempt to perfuse the vital organs in
shock , the blood is usually diverted from the skin and hence the delay in
CRT is supposed to reflect the degree of shock. As pointed out by
Carcillo JA in an excellent editorial(4) ,there are numerous studies
supporting the use of CRT and hence it is a useful tool for evaluation of
the hemodynamic status in children.
The authors of this current study have carried out both sternal and
finger tip CRT in normal children and found that there was a poor
correlation between the two. Another interesting finding was that the
finger tip CRT was faster than the sternal CRT.This finding is rather
strange and seems difficult to fit in despite the complex and intricate
relationship between arteriolar resistance, venular resistance, viscosity,
microvessel patency, polycythemia etc involved in the capillary refill. It
was also premature on part of the authors to consider resuscitation
council(RC) to re-evaluate their recommendations on CRT.
It is important for us to ensure that the CRT is carried out with
some uniform method by all child care providers and that studies on CRT
should consider assessing its utility against a set of surrogate variables
of perfusion in the normal and sick children. One must be aware of the
limitations of CRT and analyse it in conjunction with the other markers of
hemodynamic status. A normal CRT in a sick child except perhaps in warm
shock has a good negative predictive value. One could consider inventing a
simple device akin to a ball point pen with a stopwatch which delivers a
standard pressure for appropriate time on the skin surface so as to make
the process of eliciting CRT more uniform. It would be even better if the
refill measurement could be digitized to avoid any subjective error.
Irrespective of the technique used, a resource limited country is likely
to use only clinical signs or low cost devices for assessment of perfusion
in sick children with shock.
References:
1. Pandey A,John BM.Capillary refill time:Is it time to fill the
gaps.Medical Journal Armed Forces India 2013;69:97-98.
2. Gale C.Is capillary refill time a useful marker of hemodynamic
status in neonates? Arch Dis Child 2010; 95:395-397
3. Lobos A,Lee S,Menon K. Capillary refill time and cardiac output in
children undergoing cardiac catheterization. Pediatr Crit Care Med 2012;
13:136 -140
4. Carcillo JA. Capillary refill time is a very useful clinical sign
in early recognition and treatment of very sick children. Editorial on
Pediatr Crit Care Med 2012; 13:136 -140
Fairley et al(1) describe differences in growth between White and
Pakistani infants in the BiB study using mixed effects linear splines, an
approach becoming popular in the analysis of serial anthropometry. Linear
splines were used because they summarize noisy data in meaningful
parameters: an intercept and linear slope terms (connected by knots)
governing different age sections. Adding an exposure obtained estimates of...
Fairley et al(1) describe differences in growth between White and
Pakistani infants in the BiB study using mixed effects linear splines, an
approach becoming popular in the analysis of serial anthropometry. Linear
splines were used because they summarize noisy data in meaningful
parameters: an intercept and linear slope terms (connected by knots)
governing different age sections. Adding an exposure obtained estimates of
differences between ethnicities in size at the intercept and in rate of
change for each age section. Linear splines are an appealing analytical
choice, but their biological and statistical limitations are often
overlooked.
Growth follows a complex pattern of age related change and linear
splines (by their very nature) have limited ability to describe this
process. A traditional structural growth model (e.g., Berkey-Reed 1st
order(2)) may be a better choice to "describe the growth pattern". Careful
selection of knots might have improved matters (e.g., given neonatal
weight loss, a knot at age two weeks would make sense). Instead, knots
developed in the ALSPAC study were used, thereby assuming that the growth
process was the same for BiB infants (with different defining
characteristics) compared to ALSPAC infants. Further, when investigating
the effects of an exposure on growth, does it make sense to impose the
same inflection points (i.e., knots) on each response of that exposure? A
major assumption of the mixed effects linear splines used by Fairley et
al(1) was that all individuals shared the same inflection points. Applying
conventional regression to hierarchical data produces incorrect standard
errors(3) and linear spline specification that does not account for
between individual variation may have similar consequences.
Methods in other disciplines(4) have extended the flexibility of
linear splines to incorporate individual level inflection points at knots
that do not need to be specified a priori, but instead are data driven. A
promising avenue of research is to extend mixed effects linear splines for
growth modelling to include individual level inflection points; this could
be done in existing Bayesian modelling framework software(5).
1. Fairley L, Petherick ES, Howe LD, Tilling K, Cameron N, Lawlor DA,
et al. Describing differences in weight and length growth trajectories
between white and Pakistani infants in the UK: analysis of the Born in
Bradford birth cohort study using multilevel linear spline models.
Archives of Disease in Childhood 2013;98:274-9.
2. Berkey CS, Reed RB. A model for describing normal and abnormal growth
in early childhood. Human Biology 1987;59:973-87.
3. Goldstein H. Efficient statistical modelling of longitudinal data.
Annals of Human Biology 1986;13:129-41.
4. van den Hout A, Muniz-Terrera G, Matthews FE. Change point models for
cognitive tests using semi-parametric maximum likelihood. Computational
Statistics & Data Analysis 2013;57:684-98.
5. Lunn DJT, A. Best, N. Spiegelhalter, D. WinBUGS - a Bayesian modelling
framework: concepts, structure, and extensibility. Statistics and
Computing 2000;10:325-37.
I suggest breast feeding increases infant DHEA which positively affects growth and development. Please read "DHEA is the Reason Breast Milk is Beneficial," at: http://anthropogeny.com/DHEA%20Breast%20Milk.htm
Conflict of Interest:
None declared
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Fairley et al(1) describe differences in growth between White and Pakistani infants in the BiB study using mixed effects linear splines, an approach becoming popular in the analysis of serial anthropometry. Linear splines were used because they summarize noisy data in meaningful parameters: an intercept and linear slope terms (connected by knots) governing different age sections. Adding an exposure obtained estimates of...
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