eLetters

66 e-Letters

published between 2017 and 2020

  • Response to letter re: ‘Combinations of subgroup analyses and impact on results’

    We thank the letter authors for commending most of our protocol decisions. A multicenter trial is always associated with a number of compromises, e.g.  between standardization and freedom of therapy, between insufficient and overzealous data collection, and between too few and too many exploratory statistical tests.

     

    For detecting BPD, we used criteria that included all cases with requirement of supplemental oxygen or mechanical support at a postmenstrual age of 36 weeks. This definition was the same as moderate or severe BPD in the more recently formulated consensus definition, and has been used in many other previous trials, testing ventilation modes, high-frequency ventilation, steroid use, permissive hypercapnia, and many others. This made our results comparable to previously published data.

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  • Combinations of subgroup analyses and impact on results

    We read with interest the follow up study by Thome and colleagues assessing neurodevelopmental outcomes of the extremely low birth weight (ELBW) infants from the Permissive Hypercapnia in Extremely Low Birthweight Infants (PHELBI) trial1.

    This study makes an important contribution to the evidence-base on the strategy of permissive hypercapnia for ELBW infants. It is a well-powered, multicentre trial and we commend the authors for the ambitious decision to include only intubated ELBW infants and also the use of a clinician-guided treatment protocol. While the methodology allows some systematic bias, there is strong external validity with a patient population representative of ‘real-life’ clinical practice.

    We question the choice to combine the subgroups with moderate and severe bronchopulmonary dysplasia (BPD) for statistical analysis. In Table 2, we note the non-significant p-value for the combined outcome of moderate/severe BPD of 0.30 and no reported p-values for the individual subgroups moderate BPD and severe BPD. Using the raw data provided in Table 2, we calculate a p-value for severe BPD as significant at 0.01, suggesting an increase.

    There is considerable clinical difference between patients with moderate BPD (requiring FiO2 <30% at 36 weeks or discharge) and those with severe BPD (requiring FiO2 ≥30% and/or positive pressure ventilation)2. Other than increased risk of mortality and respiratory disease, severity of BPD correlates with incr...

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  • CPAP and nasal injury

    Dilini I Imbulana and coworkers have published a good systematic review of nasal injuries in preterm infants receiving non-invasive respiratory support1. They included the early work by Robertson et al.2 but not the criticism from us3 or from the company selling the device4. At that time (1996), we had experiences of treatment of about 750 newborns with early versions of Infant Flow, including extremely preterm infants. We had not a single case of significant nasal injury. Imbulana et al. rightly write that it is important to chose correct size of nasal prongs (not too small). It is also crucial to avoid a hard pressure of the CPAP device on the nose. Moderate air leaks are acceptable. Several of the lesions published by Robertson and others are probable caused by attempts to avoid air leaks by a too tight connection between the CPAP device and the nose.
    Neonatal nurses from various hospitals and countries should meet face-to-face or via Skype to discuss and compare how they adapt CPAP devices to preterm newborns.
    Infant Flow was invented by the anaesthetists Drs Gunnar Moa and Kjell Nilsson at our hospital. We were the first paediatrician and neonatologist to use Infant Flow but we haven’t received any fees or other benefit for that.
    References
    1. Imbulana DI, Manley BJ, Dawson JA, Davis PG, Owen LS. Nasal injury in preterm infants receiving non-invasive respiratory support: a systematic review. Archives of Disease in Childhood - Fetal and Neonatal...

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  • Time to explore the variation in outcome at 22-23 weeks

    I congratulate the authors for putting the results of this much needed study together and exploring the differences in survival for extremely preterm babies at 22-23 weeks. The outcome for babies born at < 26 weeks hasn't been looked at nationally since the EPICURE 2 study in 2006.
    It is interesting to note the regional variation in survival at 22-23 weeks and it warrants further exploring the following issues:
    1. Is there a variation nationally in administering antenatal steroids at <24 weeks gestation? The NICE guideline 2015 advocates:
    For women between 23+0 and 23+6 weeks of pregnancy who are in suspected or established preterm labour, are having a planned preterm birth or have P-PROM, discuss with the woman (and her family members or carers as appropriate) the use of maternal corticosteroids in the context of her individual circumstances. This is open to interpretation and may not provide consistency in administration of antenatal steroids at 23 to 23+6 weeks. There is no guidance for <23 weeks. It will be useful to explore the practice nationally.
    2. The practice for resuscitation at <23 weeks is likely to be variable. The latest national guideline BAPM 2008 advocates If gestational age is certain and less than 23+0 (i.e. at 22 weeks) it would be considered in the best interests of the baby, and standard practice, for resuscitation not to be carried out. The units who were resuscitating babies <23 weeks were deviating from...

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  • Neonatal rotavirus immunisation, and breast feeding friendly hospitals
    John C Dearlove

    Sirs, we were surprised to read that11 out of 56 units in the resource rich UK did not administer Rotavirus vaccine to their babies. (1) Thirty years ago, one of us described a neonatal rotavirus outbreak that had a considerable morbidity (2). Although these outbreaks continue(3.), some low resource units like ours (Birth rate 3000/year) are accredited as Breast Feeding Friendly and have adopted a very enthusiastic breast...

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  • Physiolgical transition ?

    Dear Sir,

    We congratulate the authors on this study of neonatal transitional circulation performed so quickly after birth. The authors state that the ductal flow ratio reported in their study reflects pulmonary and haemodynamic transition and can be used to monitor neonatal transition in healthy infants. The implication is that their study describes a physiological transition in healthy term infants, but we question that this is the case.

    Delivery by elective caesarean section is not a physiological birth but it does permit the neonate an atraumatic birth. We are particularly concerned that the transition may have been disrupted by the timing of cord clamping which was between 30 and 60 seconds. While this is considered delayed cord clamping by some, most guidelines recommend a minimum of 60 seconds have elapsed before the circulation is interrupted by cord clamping. The WHO advises 3 minutes.(1) Not all of the babies in the series had established respiration before clamping and cord clamping before the onset of respiration has a marked effect on cardiac output.(2) It is therefore questionable that the mean and range of results published represents a normal transition in healthy infants.

    The normal fetal circulation is well described with the two ventricles pumping in parallel, the right ventricular output being significantly more than the left and the flow across two shunts, right to left in the ductus arteriousus and right to left across the foram...

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  • Neonatal ethanol/isopropanol exposure in isolettes

    Sir,

    We read Hsieh et al's paper with much interest. In an experimental study of ethanol introduction in an empty isolette, they conclude that neonates in isolettes are at risk of of inadvertent exposure to ethanol from hands cleaned with ethanol-based hand sanitiser.
    We would like to share with the readers of Arch Dis Child Fetal Neonatal, the results of a similar study conducted in 2011. Measurements of isopropanol/ethanol exposure were conducted for 9 neonates nursed in incubators1. We found very variable exposure profiles with peak isopropanol/ethanol value of 1982, respectively 906 ppm. A wide range of possible exposure situations were also investigated using a one-box dispersion model2. Both our clinical and experimental papers offered different approaches to reduce the potential isopropanol/ethanol exposure for neonates nursed in isolettes.
    We were delighted to read that the results from Hsieh et al. were concordant with our findings. We believe that this new publication gives further evidence and emphasis on the, unfortunately often underestimated, issue of neonatal exposure to gaseous pollutants.

    1 Paccaud et al. Hand-disinfectant alcoholic vapors in incubators. JNPM 4(1):15-19, 2011
    2 Vernez et al. Solvent vapours in incubators: a source of exposure among neonates? Gefahrstoffe -Reinhaltung der Luft 71 (5):209-214, 2011

  • Re: Logistic regression equation and (co)variance matrix for estimating developmental outcome in very preterm infants

    Dear Dr. Degraeuwe,

    We thank you very much for your question and we would appreciate having the opportunity to share the full results of the regression analyses for our 3 outcomes: neurodevelopmental impairment, significant neurodevelopmental impairment and significant neurodevelopmental impairment or death. The omission of this information was due solely to the manuscript restrictions on words and tables. We agree with you that this information is useful. As we are not able to provide tables in an e-letter, we would be happy to share this information via e-mail with any interested reader.

    Sincerely,

    Anne Synnes, MDCM, MHSC, FRCPC
    Neonatologist, BC Women’s Hospital and Health Centre,
    Clinical Professor, Department of Pediatrics, University of British Columbia
    Director, Canadian Neonatal Follow-Up Network
    Vancouver, Canada

  • Response: High flow nasal cannula versus NCPAP: No difference in time to full oral feeds

    We are delighted that our work received the attention of the neonatal community. The protocol in the study was exactly as stated in our paper, oral feeds were offered at least once in 72 hours, more often if cues were evident. As cue-based feeding depends on individual infants’ physiological wellbeing and readiness to feed a traditional feeding guideline based on volume and time would be contradictory. The cue based feeding might have some effect on earlier achievement of the full oral feeding.(1) Usual total feeding volume in our unit is between 120 ml/kg/day to 180 ml/kg/day and this depends on several factors: co-morbidity (e.g. patent ductus arteriosus, chronic lung disease), type of milk (maternal breast milk, donor breast milk, different type of formulas), weight gain. The total enteral intake would not be feasible to protocolize. The volume taken orally (volume per feed and hike of feeds) was determined by the effort and energy of each individual baby as opposed to following any particular schedule (as mentioned earlier cue-based or infant-led feeding). As our cohort consisted of infants on full enteral feeding, there was no specific definition of feeding intolerance and indeed we did not identify any problems with feeding intolerance in the trial.
    The first oral feed in our trial was 9.3 ± 6.5 days after randomization in High Flow (HF) group and 10.9 ± 4.8 days in nasal Continuous Positive Airway Pressure (CPAP) group, that is 33.3 ± 0.9 weeks of postmenstru...

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  • RE: Hemoglobin discordances in twins: Still unanswered!!!

    We thank dr. Kumar and dr. Yadav for their interest in our study. We hope that by stating ‘delayed cord clamping may not be advisable in second-born MC twins after vaginal birth’, we expressed that gynecologists could consider to deviate from the international guidelines in some cases. It is possible that not all babies will benefit from placental transfusion in a similar way. However, we certainly agree with dr. Kumar and dr. Yadav that the optimal timing of umbilical cord clamping in twins warrants further investigation.

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