We thank Dr Gabrielle Laing for her comments regarding our study.[1]
Specificity is indeed valuable, but due to the way we defined our infant
cohorts the denominator (total live births minus those infants with
abnormalities) could only be approximated by using the obstetric data from
each study hospital during the period of the study. The sensitivity and
positive predictive values were presented in...
We thank Dr Gabrielle Laing for her comments regarding our study.[1]
Specificity is indeed valuable, but due to the way we defined our infant
cohorts the denominator (total live births minus those infants with
abnormalities) could only be approximated by using the obstetric data from
each study hospital during the period of the study. The sensitivity and
positive predictive values were presented in our paper as this data was
collected directly. However in view of her comments the calculated
specificities in the cardiac group were 2,760/2,765 (99.82%) for
paediatric trainees, and 2,233/2,234 (99.96%) for advanced neonatal nurse
practitioners (ANNPs)(p<_0.05. in="in" the="the" eye="eye" group="group" paediatric="paediatric" trainees="trainees" displayed="displayed" a="a" calculated="calculated" specificity="specificity" of="of" _2770="_2770" _2774="_2774" _99.86="_99.86" with="with" _2234="_2234" _2238="_2238" _99.82="_99.82" for="for" annps="annps" p="p"/>0.05). In the hip group calculated
specificity was 2,600/2,756 (94.3%) for paediatric trainees and
2,012/2,218 (90.7%) for ANNPs (p<_0.05. thus="thus" it="it" would="would" appear="appear" that="that" annps="annps" are="are" more="more" specific="specific" than="than" paediatric="paediatric" trainees="trainees" when="when" detecting="detecting" cardiac="cardiac" abnormalities="abnormalities" similar="similar" eye="eye" and="and" less="less" for="for" hip="hip" abnormalities.="abnormalities." this="this" latter="latter" result="result" was="was" mainly="mainly" to="to" be="be" accounted="accounted" by="by" the="the" referring="referring" _70="_70" clicky="clicky" hips="hips" compared="compared" _40="_40" referred="referred" _-="_-" is="is" difficult="difficult" know="know" whether="whether" due="due" over-referral="over-referral" or="or" under-referral="under-referral" of="of" a="a" high-risk="high-risk" group="group" trainees.="trainees." p="p"/> We agree with Dr Laing that likelihood ratios are helpful and thank
her for the table. In view of the fact that a high likelihood ratio for a
positive test and a low value for a negative test indicates a more
effective screening test,[2] her table demonstrates a clear trend that ANNP
screening appears more effective than that performed by paediatric
trainees in five out of six likelihood ratios.
We disagree that a rate of 1.05% for hip abnormalities is ten-times
the rate seen previously. Using similar criteria other groups have quoted
rates of 1.1%[3] and 1.2%[4].
We endorse Dr Laing's statement that both over-referral and under-
referral have consequences. In this regard, our data suggests that ANNPs
are as effective as trainee paediatricians at detecting hip, eye, and
cardiac abnormalities during the neonatal examination, and may in fact be
more effective.
Tim Lee
St James's University Hospital
Ruth Skelton
The General Infirmary at Leeds
Caryl Skene
Hull and East Yorkshire Hospitals NHS Trust
References
(1) Lee TWR, Skelton RE, Skene C. Routine neonatal examination -
Effectiveness of trainee paediatrician compared to advanced neonatal nurse
practitioner. Arch Dis Child Fetal Neonatal Ed 2001; 85: F100-F104.
(2) Gilbert R, Logan S. Assessing diagnostic and screening tests. In:
Evidenced based paediatrics and child health, edited by Moyer VA, Elliot
EJ, Davis RL et al. BMJ Books 2000; P24-36.
(3) Falliner A. Hahne HJ. Hassenpflug J. Sonographic early hip screening and
early management of developmental dysplasia of the hip. Journal of
Paediatric Orthopaedics 1999. Part B. 8(2): 112-7.
(4) Committee on Quality Improvement, American Academy of Pediatrics -
Clinical Practice Guidelines: Early detection of developmental dysplasia
of the hip. Pediatrics 2000; 105: 896-905.
With great interest we read the paper by Whyte et al regarding the
practice of premedication before intubation in UK neonatal units.[1]
Their finding that only 37% of the units gave any sedation before
intubation is worrysome in view of the known physiologic responses to
awake intubation.[2-4] However, one potential bias in their study design
was not discussed.
With great interest we read the paper by Whyte et al regarding the
practice of premedication before intubation in UK neonatal units.[1]
Their finding that only 37% of the units gave any sedation before
intubation is worrysome in view of the known physiologic responses to
awake intubation.[2-4] However, one potential bias in their study design
was not discussed.
Since the information regarding this subject was
derived from telephonic interviews with the sister in charge of the unit
the results might merely reflect the policy of the unit as perceived by
this person and not the practice of the individual neonatologist
performing or supervising the intubation. Whether this would result in
underscoring or overscoring on the subject remains to be answered.
In our
experience sustantial interindividual variation exists among
neonatologists in the use of premedication before intubation of neonates.
In March of 1999 we performed a written survey among all neonatologists
and fellows working on each of the 10 neonatal intensive care units
(NICUs) in The Netherlands. The response rate was 77/87 (89%). Of the
respondents, 58 (76%) always gave some form of analgesia or sedation prior
to intubation, 13 (16%) only sometimes gave premedication, whereas 6 (8%)
never gave premedication. Of those who always gave premedication 33 (57%)
always combined the use of sedation with a muscle relaxant. Only 15 (17%)
used a written protocol for premedication.
Similar to Whyte’s results
great variation existed with regard to the choice and dose regimen of the
premedication. Morphine was the most widely used opioid, followed by
fentanyl and pethidine. Midazolam was the most popular sedative. On a few
occasions, ethomidate was mentioned as anaesthetic drug. Atropine was
sometimes used in patients with proven rapid onset of reflex bradycardia.
From these results it appears that premedication before intubation of
neonates is the rule rather than the exception in the NICU environment in
The Netherlands, although overscoring cannot be ruled out. When analysed
on a per NICU basis it was obvious that a great intra-NICU variation in
the practice of premedication exists.
Our results closely resemble those
of a recent survey among Canadian neonatologists which showed that in
approximately 75% of cases some premedication before intubation is used in
Canadian NICUs.[5] It would be interesting to see the results of a
survey among neonatologists in the UK.
The known physiological responses
to awake intubation include bradycardia, hypertension, hypoxemia,
laryngospasm and increased intracranial pressure (2-4). Moreover, awake
intubation requires more attempts, is more time-consuming and is
accompanied with more mucosal damage than premedicated intubation.[6]
Optimal prevention of these adverse effects probably requires the
combination of a vagolytic, an opioid and a muscle relaxant.[7]
Therefore, in our institution the combination of atropine (0.1 mg),
morphine (0.05-0.1 mg/kg) and vecuroniumbromide (0.05-0.1 mg/kg) is
routinely applied with great satisfaction. We fully agree with Whyte et al[1] that there is now sufficient evidence to support the routine practice
of premedication for elective intubation of neonates. Indeed, more
research is needed to investigate the optimal drug and dose regimen.
REFERENCES
1. Whyte S, Birrell G, Wyllie J: Premedication before intubation in
UK neonatal units. Arch Dis Child Fetal Neonatal Ed 2000;82:F38-F41.
2. Marshall TA, Deeder R, Pai S, Berkowitz GP, Austin TL: Physiologic
changes associated with endotracheal intubation in preterm infants. Crit
Care Med 1984; 12(6):501-3.
3. Kelly MA, Finer NN: Nasotracheal intubation in the neonate: Physiologic
responses and effects of atropine and pancuronium. J of Pediatrics
1984;105:303-9.
4. Friesen RH, Honda AT, Thieme RE: Changes in anterior fontanel pressure
in preterm neonates during tracheal intubation. Anesth Analg 1987;66:874-
8.
5. Vogel S, Gibbins S, Simmons B, Shah V: Premedication for endotracheal
intubation (EI) in neonates: A Canadian Perspective. Pediatric Research
2000;47(4):438A.
6. Oei J, Hari R, Lui K: Suxamethonium, atropine and morphine as induction
for neonatal nasotracheal intubation: A randomised controlled trial.
Pediatric Research 2000;47(4):421A.
7. Barrington KJ, Byrne PJ: Premedication for neonatal intubation. Am J of
Perinatol 1998;15(4):213-6.
Harry Molendijk, MD,
Neonatologist
Anneke Jaarsma, MD,
Neonatologist
Beatrix Children’s Hospital
Department of Pediatrics, Subdivision of Neonatology
University Hospital Groningen, P.O. Box 30001
9700 RB Groningen, The Netherlands
The paper by Aubrey and Yoxall[1] concludes that Advanced Neonatal
Nurse Practitioners (ANNPs) are effective in the resuscitation of preterm
babies at birth. In the same edition, Lee et al.[2] show that ANNPs in
East Yorkshire are significantly more effective in detecting abnormalities
during the neonatal check.
Neither of these results surprise me. ANNPs are intelligent,
motivated and mos...
The paper by Aubrey and Yoxall[1] concludes that Advanced Neonatal
Nurse Practitioners (ANNPs) are effective in the resuscitation of preterm
babies at birth. In the same edition, Lee et al.[2] show that ANNPs in
East Yorkshire are significantly more effective in detecting abnormalities
during the neonatal check.
Neither of these results surprise me. ANNPs are intelligent,
motivated and most importantly, trained for these relatively self
contained tasks. Quite rightly, they can expect a structured training
programme and will have to show competence in these tasks before being
allowed to operate independently of direct supervision.
Paediatric SHOs on the other hand receive an 'ad hoc' training with
no demonstration of competence. In my experience, preparation for the
neonatal examination usually involves a half-hour lecture and a brief
demonstration by the registrar before being pointed in the direction of
the postnatal ward.
Neonatal resuscitation receives slightly more weight. Junior
paediatricians are usually accompanied to deliveries 'until they can
intubate'. They learn by a supervised apprenticeship. There is usually
middle grade cover to ensure safety, but in no way is this comparable to
the way ANNPs or anaesthetists are trained.
Changes in staffing and service delivery will undoubtedly occur as
Trusts are forced to make posts compliant with both the New Deal[3] and
the European Working Time Directive[4]. This will make it both attractive
and necessary to employ ANNPs to carry out these tasks in place of
doctors.
The implications are rather worrying. Are paediatricians to lose
their technical resuscitation skills? Similarly, are SHOs to be denied the
necessary (if at times slightly tedious) experience of the new born
examination?
These studies demonstrate that junior paediatricians suffer as a
result of their traditional 'service based training'. They need a proper,
structured education with an assessment of competence before complementing
the work of the ANNPs on both the labour and postnatal wards.
Dr Ieuan Davies
SpR Paediatrics
University Hospital of Wales
References
(1) Aubrey WR, Yoxall CW. Evaluation of the role of the neonatal nurse
practitioner in resuscitation of preterm infants at birth. Arch Dis Child
Fetal Neonat Ed 2001;85:F96-F99.
(2) Lee TWR, Skelton RE, Skene C. Routine neonatal examination:
effectiveness of trainee paediatrician compared with advanced neonatal
nurse practitioner. Arch Dis Child Fetal Ed 2001;85:F100-F104.
(3) NHS Management Executive. Junior Doctors-The New Deal. London:
Department of Health;1991.
(4) European Working Time Directive. 93/104/EEC.
International randomised controlled trial by Dr Baumer[1] concluded that there was no benefit of patient triggered ventilation (PTV), but an added risk of increased pneumothorax in those less than 28 weeks gestation. In the same issue Beresford et al[2] concluded in a similar trial (with slightly more mature newborns 29 weeks vs 27), that PTV was feasible with no significant differences noted in medium term outcom...
International randomised controlled trial by Dr Baumer[1] concluded that there was no benefit of patient triggered ventilation (PTV), but an added risk of increased pneumothorax in those less than 28 weeks gestation. In the same issue Beresford et al[2] concluded in a similar trial (with slightly more mature newborns 29 weeks vs 27), that PTV was feasible with no significant differences noted in medium term outcomes.
Chronic lung disease (CLD) is multifactorial in origin and in Baumer’s trial significant factors, like ventilation pressures, intrauterine growth retardation, use of post natal steroids and nasal CPAP use, have been not compared between the groups.
Intrauterine growth retardation has been shown to be an important risk factor for CLD.[3]
In a trial where primary outcome is chronic lung disease omission of the data regarding use of post natal steroid use is quite surprising. Meta-analysis of the use of dexamethasone in VLBW infants has shown significant reduction in CLD at 36 weeks post conceptional age.[4]
The use of nasal continuous positive airway pressure (nasal CPAP) that has been shown to influence the incidence of CLD, 5 fails a mention in their trial. Breseford et al did not use nasal CPAP in any of their infants, but used synchronised intermittent mandatory ventilation (SIMV) in the weaning phase.
To the clinician, who has to make the choice of using these commonly available tools to reduce death and morbidity in this vulnerable group of infants, the choice is clear or more unclear? I leave the readers to decide.
References:
1. Baumer JH. International randomised controlled trial of patient triggered ventilation in neonatal respiratory distress syndrome. Arch Dis Child Fetal Neonatal Ed 2000;82:F5-F10.
2. Beresford MW, Shaw NJ, Manning D. Randomised controlled trial of patient triggered and conventional fast rate ventilation in neonatal respiratory distress syndrome. Arch Dis Child Fetal Neonatl Ed 2000;82:F14-F18.
3.Korhonen P, Tammela O, Kovisto AM, Laippala AM, Ikonen S. Frequency and risk factors in bronchopulmonary dysplasia in a cohort of very low birth weight infants. Early Hum Dev 1999;54:245-58.
4. Bhuta T, Ohlsson A. Systematic review and meta-analysis of early postnatal dexamethasone for prevention of chronic lung disease. Arch Dis Child Fetal Neonatal Ed 1998;79:F26-33.
5. Josson B, Katz-Salamon M, Faxelius G, Broberger U, Lagercrantz H. Neonatal care of very low birthweight infants in special care units and neonatal intensive care units in Stockholm. Early nasal continuous positive airway pressure versus mechanical ventilation: gains and losses. Acta Paediatr Suppl 1997;419:4-10.
Aubrey and Yoxall conclude that Advanced Neonatal Nurse Practitioners
(ANNPs) are effective in the resuscitation of preterm infants at birth
[1]. The authors are careful not to conclude that ANNPs are more effective
than medically led teams but they have made a comparison nevertheless. The
data presented suggest that the infants resuscitated by ANNP led teams
were intubated more quickly, received surfactan...
Aubrey and Yoxall conclude that Advanced Neonatal Nurse Practitioners
(ANNPs) are effective in the resuscitation of preterm infants at birth
[1]. The authors are careful not to conclude that ANNPs are more effective
than medically led teams but they have made a comparison nevertheless. The
data presented suggest that the infants resuscitated by ANNP led teams
were intubated more quickly, received surfactant earlier, and were less
likely to be hypothermic on admission to the neonatal unit.
We believe such comparisons are not justified because of two major
sources of bias: failure to use randomisation and contamination.
Firstly, the study allocated the infants to ANNP or medically led
resuscitation on the basis of existing practice, rather than by
randomisation. The ANNPs worked exclusively during the daytime. A greater
proportion of medically led resuscitation therefore occurred out of normal
working hours. During these times, infants would be more likely to be born
at short notice and the medical staff would have less time to prepare for
the delivery, particularly if they have co-existing commitments on a
neonatal unit with lower night-time staffing levels (no ANNPs, less
medical and nursing staff). This hurried preparation, combined with lower
night-time ambient temperatures, may explain the observed differences.
Secondly, the infant groups were determined by who wrote the
resuscitation notes. Thus, an ANNP led resuscitation that required senior
medical help might then be classed as a medically led resuscitation (and
vice versa). The infants need to be analysed in groups according to
initial resuscitation team. This second point also highlights the problem
of trying to record precise data (such as time to intubation) from
retrospective written accounts of the resuscitation.
Both these sources of bias were not quantified and therefore could
not be corrected through multivariate analysis.
We welcome the fact that the authors have made efforts to evaluate
ANNP led resuscitation of preterm infants. Before any conclusions are to
be drawn about the relative merits or deficiencies in ANNP or junior
doctors training, however, further comparisons need to use more rigorous
methodology. Future prospective studies might compare only infants born
during the daytime and allocated to a resuscitation team by randomisation.
References
(1) Aubrey WR, Yoxall CW. Evaluation of the role of the neonatal
nurse practitioner in resuscitation of preterm infants at birth. Arch Dis
Child Fetal Neonatal Ed 2001;85:F96-F99.
I would like to mention two other modes of ventilation used during the immediate post extubation period. They deserve a mention in the excellent article on the current issues in weaning of preterm infants from assisted ventilation.[1] Nasopharyngeal-synchronised intermittent mandatory ventilation (NP-SIMV) and nasal synchronised intermittent positive pressure ventilation (nSIPPV) have been studied in two trials wi...
I would like to mention two other modes of ventilation used during the immediate post extubation period. They deserve a mention in the excellent article on the current issues in weaning of preterm infants from assisted ventilation.[1] Nasopharyngeal-synchronised intermittent mandatory ventilation (NP-SIMV) and nasal synchronised intermittent positive pressure ventilation (nSIPPV) have been studied in two trials with favourable results.
The first trial compared prospectively the incidence of respiratory failure in 41 VLBW infants randomised in immediate post extubation period to receive either NP-SIMV or nasopharyngeal continuous positive airway pressure (NCPAP).[2] The incidence of respiratory failure after extubation in NP-SIMV group was significantly lower than in the NCPAP group (5% vs 37% respectively; p=0.016). Few adverse effects were noted in the NP-SIMV mode namely one case of moderate abdominal distension and another of self resolving epistaxis. The authors had demonstrated in their pilot study[3] that they were able to avoid reintubation in 70% of the high risk newly extubated premature infants.
Another Study by Moretti et al[4] studied the gas exchange and respiratory effort during nasal synchronised intermittent positive pressure ventilation (nSIPPV) and nasal CPAP. The nSIPPV group demonstrated significant increased tidal volume, minute volume and decreased respiratory effort (p<_0.01 and="and" transcutaneous="transcutaneous" carbon="carbon" dioxide="dioxide" levels.="levels." the="the" authors="authors" concluded="concluded" that="that" nsippv="nsippv" may="may" provide="provide" more="more" ventilatory="ventilatory" support="support" than="than" ncpap="ncpap" in="in" post="post" extubation="extubation" period="period" with="with" less="less" patient="patient" inspiratory="inspiratory" effort.="effort." p="p"/>
Both are relatively non-invasive mode of ventilatory support during immediate post extubation period. There is a significant reduction in the reintubation rates (37% to 5%),[2] hence they appears an attractive mode to use in these high risk infants. Larger trials may be needed before the mode is universally accepted.
References
(1) Sinha SK, Donn S. Weaning from assisted ventilation: art or science? Arch Dis Child Fetal Neonatal Ed 2000;83:F64-70.
(2) Friedlich P, Lecart C, Posen R, Ramicone E, Chan L, Ramanathan R. A randomised trail of nasopharyngeal-synchronised intermittent mandatory ventilation versus nasopharyngeal continuous positive airway pressure in very low birth weight infants after extubation. J Perinatol 1999;19:413-18.
(3) Lecart C, Friedlich P, Ramanathan R, deLemos R. The combined use of intermittent mandatory ventilation (IMV) and nasopharyngeal CPAP (NP-CPAP) in premature infants following extubation. Pediatr Res 1997;41:258A.
(4) Moretti C, Gizzi C, Papoff P, Lampariello S, Capoferri M, Calcagnini G, Bucci G. Comparing the effects of nasal synchronised intermittent positive pressure ventilation (nSIPPV) and nasal continuous positive pressure (nCPAP) after extubation in very low birth weight infants. Early Hum Dev 1999;56:167-77.
French and Evans have pointed out several limitations of our study
which we had already discussed within the original paper. As there was no
randomistaion performed, it is not possible to conclude that one group was
better or worse than another at resuscitating preterm babies. The
concerns expressed about the accuracy of retrospectively collected data
are equally valid.
French and Evans have pointed out several limitations of our study
which we had already discussed within the original paper. As there was no
randomistaion performed, it is not possible to conclude that one group was
better or worse than another at resuscitating preterm babies. The
concerns expressed about the accuracy of retrospectively collected data
are equally valid.
However, this was not intended to be a randomised controlled trial
intended to determine whether ANNPs are 'better' or 'worse' than junior
medical staff at resuscitating preterm babies at birth. As stated in the
article, this was an audit of current clinical practise within our
service. The conclusion we have reached is that there is no evidence that
ANNPs are less proficient than junior medical staff at resuscitating
preterm babies.
There were some differences between the two groups. These tended to
be in favour of the ANNP group, but given the well described limitations
of the study, it is not possible to reach any conclusions from these
differences. These sorts of observations are only useful for hypothesis
generation. As French and Evans have pointed out, it would be possible to
test such a hypothesis with a randomised controlled trial using the design
they propose. However, it would be a fairly sterile exercise which would
not address the other clinical benefits of utilising ANNPs or address the
impact of ANNPs on medical training and we do not intend to perform such a
study.
Visveshwara's eLetter[1] emphasises that the results of the trigger trial should
not be interpreted as demonstrating lack of benefit for patient triggered
ventilation using other sensors or ventilators. I would concur with this
statement, which was emphasised in the paper.
However, Visveshwara should not be surprised to find different
outcome rates in the patients whose results he presents,...
Visveshwara's eLetter[1] emphasises that the results of the trigger trial should
not be interpreted as demonstrating lack of benefit for patient triggered
ventilation using other sensors or ventilators. I would concur with this
statement, which was emphasised in the paper.
However, Visveshwara should not be surprised to find different
outcome rates in the patients whose results he presents, as they are a
different group of infants from those reported in either study. The
evidence for benefit from the impedance technique is unconvincing, based
as it is on a controlled study of 40 infants and
a further 110 uncontrolled cases from one centre. A multicentre randomised
controlled trial of sufficient power is needed to demonstrate benefit from
the impedance and patient terminated ventilation techniques he describes.
To date such a study has not been performed.
Yadav's eLetter[2] suggests that important risk factors have not been compared in
the study. He describes two different types of risk factor, namely
inherent factors in the infant (intrauterine growth retardation) and
treatments applied to the infants (ventilation pressures, use of postnatal
steroids and of CPAP).
In a large randomised controlled study individual patients will have
varying degrees of risk for the outcomes being measured. The purpose of
the study design is to allocate patients in such a way that the overall
risk for each arm is the same. The larger the study, the less likely that
there will be an unequal balance of risk, assuming that the randomisation
process is performed correctly. We reported very similar birthweights and
gestations in the two groups. The proportion of growth retarded infants
was therefore allocated equally, and will not have biased the results.
A study comparing two modes of ventilation cannot be conducted with the
attendant clinicians blind to treatment allocation. The study protocol
required all other treatments to be applied equally to infants in both
arms of the study. There were written treatment protocols for each mode of
ventilation. However, it is still possible that other treatments could
have been applied unequally, with the possibility of bias resulting.
Interpretation of ventilator pressures is difficult, as in the
trigger ventilation technique weaning was undertaken at lower peak
inspiratory pressures. In Plymouth, trigger ventilated infants entered in the trial had slightly lower peak inspiratory pressures in the first 72 hours,
consistent with the different weaning policy. However, as the duration of
ventilation did not differ between the groups, it is reasonable to
conclude that there was no systematic bias in the application of
ventilation.
Information on the postnatal use of steroids was collected in the
trial. There was no difference in the proportion of infants receiving
postnatal steroids (25.5% vs 26.0%), nor in the postnatal age at which
they were first administered (median 15 vs 17 days). There is therefore no
evidence of bias resulting from their use.
The use of CPAP for weaning from ventilation has not been
demonstrated to reduce chronic lung disease in randomised controlled
trials. The paper Yadav cites discusses the possible benefits of a policy
of early use of nasal CPAP. This is not relevant to the trigger trial, as
infants recruited were by definition already being ventilated.
I would also like to qualify Yadav's statement that we found an increased
risk of pneumothorax in infants less than 28 weeks gestation. The
difference was not statistically significant, suggesting that the observed
difference may have occurred as a result of chance.
The trial therefore shows no evidence of bias, and the finding that
patient triggered ventilation has no additional benefit over intermittent
mandatory ventilation using the ventilators and techniques studied remains
valid. The trial cannot assist clinicians in their choice of other
modalities of support such as early use of CPAP or postnatal steroid use,
and is applicable both to growth retarded as well as appropriately grown
preterm infants.
Dr JH Baumer
on behalf of the trigger trial collaborators
References
(1) Visveshwara N. 'PTV': should it be patient triggered and patient terminated
ventilation? Arch Dis Child Fetal Neonatal Ed [Rapid Response] 27 June 2000
(2) Yadav M. To trigger or not to trigger? Arch Dis Child Fetal Neonatal Ed [Rapid Response] 5 July 2000
As highlighted in a recent edition of ADC Fetal and Neonatal edition,[1, 2] there is increasing concern about the
previously unreported high levels of neonatal group B
Streptococcal (GBS) infections in the UK. It is indeed
most important that we have national statistics for regional
variations in GBS infection, for it is only when we have
this information that we can begin to produce evidence based
guid...
As highlighted in a recent edition of ADC Fetal and Neonatal edition,[1, 2] there is increasing concern about the
previously unreported high levels of neonatal group B
Streptococcal (GBS) infections in the UK. It is indeed
most important that we have national statistics for regional
variations in GBS infection, for it is only when we have
this information that we can begin to produce evidence based
guidelines. It is however important that as well as
establishing the true incidence of GBS in the UK that we are
also clear about the data on which we base our
recommendations.
In the commentary following our paper entitled Neonatal
Group B Streptococcal Infection in South Bedfordshire[2]
Nicoll and Heath refer to the incidence at which a risk
factor based versus a screening approach to the prevention
of Group B Streptococcus would be cost effective, quoting
from a commentary by Isaacs.[3] The original article by
Mohle-Boetani et al[4] from which these data were derived,
actually gives figures of >0.65 and >1.45/1000 live births
at which a risk factor and screening based approach,
respectively would be cost effective. This contrasts with
those quoted by Isaacs,[3] and Nicoll and Heath[1] of 0.6
and >1.2/1000 live births.
More importantly it should be noted that these figures are
obtained from a study which used significantly different
criteria for both the definitions of a risk factor and on
the decision to treat. In the paper by Mohle-Boetani et al[4] the risk factor approach for treatment involved
treatment of both "teenagers or Blacks who developed labor
complications". The latter included either a temperature of
>37.5ºC or prolonged rupture of membranes (PROM) for >12
hours or preterm labor <_37 weeks="weeks" of="of" gestation.="gestation." this="this" is="is" obviously="obviously" a="a" quite="quite" different="different" population="population" from="from" those="those" defined="defined" in="in" the="the" cdc="cdc" guidelines5="guidelines5" where="where" all="all" mothers="mothers" who="who" go="go" into="into" preterm="preterm" labour="labour" _37="_37" gestation="gestation" or="or" have="have" prom="prom" _="_"/>18 hours)
or have a temperature (>38ºC) would be offered treatment
under a risk factor based strategy. The screening group in
the paper by Mohle-Boetani et al[4] were screened at 26-28
weeks gestation not 34-35 weeks as in the CDC guidelines,
the latter interval being considered to be when colonisation
status is most predictive of colonisation at delivery. Also
treatment was only given if the mothers also developed
intrapartum risk factors, (temperature >37.5º C or PROM >12
hours or preterm labor).
Mohle-Boetani et al conclude "The strategy we developed is
not generally applicable because different populations might
have different risk factors for delivery of infants with GBS
disease." In the study population 40% of births occurred in
women who were teenagers or Black.
It is important that before these figures become established
in the current literature we review the original data and
the premises on which it is based. It is important to pay
attention to crucial differences in the composition of
different populations and the risk factors employed in
different studies. As new guidelines are being developed we
should not make recommendations based on incorrect
information.
References
(1) Nicoll A, Heath P. Commentary. Arch Dis Child Fetal
Neonatal Ed 2000;82:F207.
(2) Beardsall K, Thompson MH, Mulla RJ. Neonatal Group B
streptococcal infection in South Bedfordshire, 1993-1998.
Arch Dis Child Fetal Neonatal Ed 2000;82:F205-7.
(3) Isaacs D. Prevention of early onset group B streptococcal
infection: screen, treat, or observe? Arch Dis Child Fetal
Neonatal Ed 1998;79:F81-2.
(4) Mohle-Boetani JC, Schuchat A, Plikaytis BD, Smith JD, Broome CV. Comparison of prevention strategies for neonatal
group B streptococcal infection. A population-based
economic analysis. JAMA 1993;270:1442-8.
(5) Centers for Disease Control. Prevention of perinatal
group B streptococcal disease: a public health perspective. MMWR May 31, 1996;45(RR-7):1-24.
The recent report on Malignant Infantile Osteopetrosis
(MIOP) presenting with neonatal hypocalcaemia highlights the importance of
early recognition of a rare but treatable disorder.[1]
We would like to point out that recognition in the neonate is
difficult, as many of the characteristic manifestations have not had time
to develop. The normal sequence of events leading to the diagnosis being
ma...
The recent report on Malignant Infantile Osteopetrosis
(MIOP) presenting with neonatal hypocalcaemia highlights the importance of
early recognition of a rare but treatable disorder.[1]
We would like to point out that recognition in the neonate is
difficult, as many of the characteristic manifestations have not had time
to develop. The normal sequence of events leading to the diagnosis being
made is usually via a known family history or by radiologists commenting
on increased bone density, seen on x-ray.
In our experience of two related siblings, the mode of presentation,
in prematurity, was through a fracture of a long bone. This has not been
reported previously in the preterm neonate.
A suggested hypothesis is that the imbalance of osteoblast and
osteoclast function, which is represented in the article as leading to
hypocalcaemia, also leads to faulty and haphazard bone modelling, thus
making osteopetrotic bones prone to fractures.
ANIRBAN MAJUMDAR
Alder Hey Children’s Hospital
Liverpool, UK
NICK WILD
Warrington District General Hospital
Warrington, UK
Reference
(1) Srinivasan M, et al. Malignant infantile osteopetrosis presenting
with neonatal hypocalcaemia. Arch Dis Child Fetal Neonatal Ed 2000;83:F21-3.
Dear Editor,
We thank Dr Gabrielle Laing for her comments regarding our study.[1] Specificity is indeed valuable, but due to the way we defined our infant cohorts the denominator (total live births minus those infants with abnormalities) could only be approximated by using the obstetric data from each study hospital during the period of the study. The sensitivity and positive predictive values were presented in...
Dear Editor
With great interest we read the paper by Whyte et al regarding the practice of premedication before intubation in UK neonatal units.[1] Their finding that only 37% of the units gave any sedation before intubation is worrysome in view of the known physiologic responses to awake intubation.[2-4] However, one potential bias in their study design was not discussed.
Since the information regarding...
Dear Editor,
The paper by Aubrey and Yoxall[1] concludes that Advanced Neonatal Nurse Practitioners (ANNPs) are effective in the resuscitation of preterm babies at birth. In the same edition, Lee et al.[2] show that ANNPs in East Yorkshire are significantly more effective in detecting abnormalities during the neonatal check.
Neither of these results surprise me. ANNPs are intelligent, motivated and mos...
International randomised controlled trial by Dr Baumer[1] concluded that there was no benefit of patient triggered ventilation (PTV), but an added risk of increased pneumothorax in those less than 28 weeks gestation. In the same issue Beresford et al[2] concluded in a similar trial (with slightly more mature newborns 29 weeks vs 27), that PTV was feasible with no significant differences noted in medium term outcom...
Dear Editor
Aubrey and Yoxall conclude that Advanced Neonatal Nurse Practitioners (ANNPs) are effective in the resuscitation of preterm infants at birth [1]. The authors are careful not to conclude that ANNPs are more effective than medically led teams but they have made a comparison nevertheless. The data presented suggest that the infants resuscitated by ANNP led teams were intubated more quickly, received surfactan...
I would like to mention two other modes of ventilation used during the immediate post extubation period. They deserve a mention in the excellent article on the current issues in weaning of preterm infants from assisted ventilation.[1] Nasopharyngeal-synchronised intermittent mandatory ventilation (NP-SIMV) and nasal synchronised intermittent positive pressure ventilation (nSIPPV) have been studied in two trials wi...
Dear Editor
French and Evans have pointed out several limitations of our study which we had already discussed within the original paper. As there was no randomistaion performed, it is not possible to conclude that one group was better or worse than another at resuscitating preterm babies. The concerns expressed about the accuracy of retrospectively collected data are equally valid.
However, this was no...
Dear Editor
Visveshwara's eLetter[1] emphasises that the results of the trigger trial should not be interpreted as demonstrating lack of benefit for patient triggered ventilation using other sensors or ventilators. I would concur with this statement, which was emphasised in the paper.
However, Visveshwara should not be surprised to find different outcome rates in the patients whose results he presents,...
As highlighted in a recent edition of ADC Fetal and Neonatal edition,[1, 2] there is increasing concern about the previously unreported high levels of neonatal group B Streptococcal (GBS) infections in the UK. It is indeed most important that we have national statistics for regional variations in GBS infection, for it is only when we have this information that we can begin to produce evidence based guid...
Dear Editor
The recent report on Malignant Infantile Osteopetrosis (MIOP) presenting with neonatal hypocalcaemia highlights the importance of early recognition of a rare but treatable disorder.[1]
We would like to point out that recognition in the neonate is difficult, as many of the characteristic manifestations have not had time to develop. The normal sequence of events leading to the diagnosis being ma...
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