eLetters

668 e-Letters

  • Nebulised Surfactant Therapy : Needs Rigorous pragmatic Trial before Implementation

    We read with great interest the article by Minocchieri et al., published in this journal and found it very interesting and relevant to the current context.1 However, we have certain observations about the conduct of the study which question its external validity.
    The authors used supplemental fractional inspired oxygen (FiO2) of 0.22–0.30 as enrollment criteria for administering surfactant. As per current standard, most of the neonatologist will not agree to give surfactant at such a low FiO2 requirement in the first 4 hours. It might be possible that many enrolled babies could have been easily managed without surfactant and it was an unnecessary intervention for them. This is further supported by the fact that in current study 28% of babies were weaned to room air in the first 4 hours, hence could not be enrolled. Also, the author's suggestion of enrolling babies requiring Fio2 > 25 % seems to be very liberal. Most of the units administer surfactant beyond 30% supplemental oxygen requirement.
    The total duration of invasive as well as any mechanical ventilation was higher in the intervention group, suggesting that the harms may outweigh the benefits.
    Although the authors showed that the intervention had its intended effect in babies born at >32 weeks’ gestation, in the current era, where universal antenatal steroid coverage is available, these babies hardly need surfactant. In this trial, a significant number of babies > 32 weeks received su...

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  • End-expiratory pressure during the respiratory transition: a more complex tale?

    I agree with the authors that the question of end-expiratory pressure at birth needs to focus on CPAP. As the authors highlight, the entirety of the preclinical literature has been performed in mechanically ventilated, intubated and sedated animals, and the role of PEEP on pulmonary blood flow during the actual respiratory transition is yet to be investigated. Neither of these limitations are insurmountable and I am confident the authors can rectify this gap in knowledge.
    The rapidly changing cardiorespiratory events immediately following birth and the concerns regarding with too low and too high a PEEP further emphasise the need for a dynamic approach to PEEP levels.

  • Response to the letter to the editor by Zhu et al regarding “Non-invasive high-frequency oscillatory ventilation in preterm infants”

    Dear Editor

    We appreciate the comments of Zhu and Shi on our crossover trial comparing nHFOV (nasal high frequency oscillatory ventilation) and nCPAP (nasal continuous positive airway pressure) in preterm infants <32 weeks gestational age after extubation from invasive ventilation for respiratory distress syndrome or after less invasive surfactant therapy.1

    The aim of our study was to evaluate the efficacy of an oscillatory pressure waveform superposed to CPAP in spontaneously breathing preterm infants suffering from hypercarbia. In our trial, patients received a CPAP of 5 – 8 cmH2O, which represents standard of care in our unit and is in line with the clinical practice within many neonatal centers.2 Individual CPAP levels were the same before (adjusted according to standard of care) and within the study periods.
    We agree with Zhu et al that increasing the CPAP level in addition to oscillations may enhance lung recruitment and ventilation. However, the effect of oscillations can hardly be differentiated from elevated CPAP levels in this scenario. Other factors than increased lung recruitment might contribute to increased CO2 clearance (e.g. increased leak flow, increased pharyngeal washout or the infants’ respiratory response). In conclusion, we cannot speculate on the effect of increased CPAP levels when testing nHFOV in our trial, but we would advise against testing differing opening pressures when comparing nHFOV to CPAP respiratory support.

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  • The secret sauce: one ingredient

    Response to The secret sauce: secrets of high performing neonatal intensive care units
    Soghier and Short highlight the importance of local contextual factors in determining the success of improvement initiatives in neonatal units. They draw attention to a number of qualitatively assessed factors, many of which are prefixed by the adjectives “effective”, “active” and, “strong” reflecting the importance of leadership and team culture in effective organisations.

    Whilst contextual factor surveys might have a place in identifying the readiness of teams to undertake active improvement, they do little to assist organisations in improving their own readiness. The features of good healthcare leadership and team culture are not readily measured, and healthcare professionals in the UK have little or no training in the attitudes and skills necessary for leadership in quality improvement.

    The Institute for Healthcare Improvement has attempted to describe the features of a high quality healthcare organisation in some detail (1). The British Association of Perinatal Medicine has recently produced Quality Indicators relating to structures and processes relevant to Quality and Patient Safety in the context of current neonatal care in the UK (2), which it is hoped will create a basis for units to develop “quality-readiness”.

    There is reason to believe that collaboration across centres might add momentum to quality improvement (3). The UK, which has good access to...

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  • Respiratory adaptation in term infants following elective caesarean section and early cord clamping ?

    Finn et al (1) describe respiratory adaptation in term infants following elective caesarean section and the other intervention of early cord clamping(2). Although the timing of cord clamping was not documented and there is no policy for delayed cord clamping at Cork University Maternity Hospital, the authors state that the neonates were transferred immediately after birth to a Panda Resuscitator and other non-invasive monitoring equipment, thus requiring early cord clamping in all infants studied.

    The aim of the study was to define newborn physiological ventilation parameters (respiratory rate (RR), TV, end-tidal carbon dioxide (EtCO2)) over the first minutes of life in healthy-term infants following ECS, in the same way that Dawson and colleagues(3) produced centile charts in 2010 detailing the normalisation of oxygen saturations over time during newborn adaptation after normal vaginal birth. All the babies studied by Dawson et al also experienced a transition of the circulatory system which was interrupted by early cord clamping but, in a study in 2014 by Smit et al(4), in which cord clamping was delayed by at least one minute, they showed that cord clamping had resulted in a lower oxygen saturation during the first few minutes after birth. The median SpO2 of the babies experiencing early cord clamping was 11, 7 and 4% lower at minute 1, 2 and 3 respectively. All these babies already had the advantage of a physiological preparation through the mechanical and hor...

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  • the value of, and obstacles to, reflective practice

    Moral distress is a good 'umbrella' term but it tends to invite diversionary philosophising when in truth we all know that work in intensive care puts enormous emotional pressures on staff. These can be attended to but as the paper shows, cannot be eradicated. Health care is not a mechanical process. As one of the subjects in this study said "if we removed moral distress we would be like robots" (F443).

    In my response to an earlier paper on this theme by the same authors https://adc.bmj.com/content/101/8/701.responses I discussed the benefits and limitations of facilitated discussions. One of the most striking comments from a neonatal intensive care nurse in one such meeting was "if you don't talk about it you don't know it's bad" http://bit.ly/1OyKcfl which perfectly captures our essential ambivalence about looking at troubling experiences in any depth. We are after all practitioners, and the tradition of 'getting on with it' - with occasional intelligent and practical thoughts on process - is the prevailing culture in most health services. Yet after almost 40 years as a psychiatrist in paediatric settings I know that there is a hunger for less systematic, but no less disciplined, attention to the daily experience of health work. This short paper 'stop running and start thinking' (Kraemer 2019...

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  • Impact of human milk on bronchopulmonary dysplasia

    Huang et al recently summarised the role of human milk (HM) in bronchopulmonary dysplasia via a systematic review and meta-analysis of the available evidence. 1 With renewed interest in exclusive HM diets and various HM products now available, it is important for health professionals to have access to quality reviews of the evidence. We would like to make some observations on the Huang article, informed by our recent review. 2
    There were two main differences in inclusion criteria between Huang’s review and ours: Huang et al included infants born <37 weeks’ gestation whereas ours was limited to very low birth weight infants. Huang et al also searched Chinese data-bases for studies in English and Chinese, in addition to conventional databases, partially addressing a limitation of our review which was restricted to studies published in English.
    In their main results, Huang et al have combined RCTs and cohort studies with forest plots showing an overall protective effect of HM. However, in Table 3, in which data are presented by study design, no effect of HM from RCTs is evident. Thus, the overall protective effect is driven by the cohort studies alone. Cochrane methods recommend that different study designs should not be combined in a meta-analysis3 as they can be expected to differ systematically. By not reporting analyses of the different study designs, Huang et al overstate the benefits of HM.
    In our recent meta-analysis 2 of human milk and morbidity...

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  • Response to letter to the editor: ‘End-expiratory pressure during the respiratory transition: a more complex tale?’

    Tessa Martherus1, André Oberthuer2, Janneke Dekker1, Stuart B Hooper3,4, Erin V McGillick3,4, Angela Kribs2, Arjan B te Pas1

    1 Department of Paediatrics, Leiden University Medical Center, Leiden, The Netherlands
    2 Department of Neonatology, Children’s Hospital University of Cologne, Cologne, Germany
    3 The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Australia
    4 Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia

    We thank the author for his interest in our review and for acknowledging that it is timely. In our review we cover the support of spontaneous breathing infants at birth with CPAP and discuss what CPAP pressures should be used. The clinical paper the author is referring to is beyond the scope of this review as the infants were 12-18 hours old and this is a completely different situation dealing with different pulmonary characteristics. In our opinion, mechanical ventilation and PEEP in intubated newborns has very little to contribute to this discussion other than indicating how end-expiratory pressures can improve lung aeration and that at high levels they have a negative impact on pulmonary blood flow and venous return. These points were adequately covered in the references cited and we also note that none of the author's papers report how high PEEP levels impact on pulmonary blood flow....

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  • Non-invasive high-frequency oscillatory ventilation in preterm infants

    To the editor:
    We appreciate the work by Klotz et al., published in this journal1, who presented a randomized controlled cross-over trial to determine whether noninvasive high-frequency oscillatory ventilation (nHFOV) decreases CO2 partial pressure(pCO2) in premature infants more effectively than non-invasive continuous positive airway pressure(nCPAP). In this trial, they assigned 26 premature infants of less than 28 weeks’gestational age (GA) to receive either nHFOV or nasal continuous positive airway pressure (nCPAP) immediately after extubation or non-invasive
    surfactant treatment. The authors could not etablish an increased
    carbon dioxide clearance applying nHFOV compared with
    nCPAP in this cohort of preterm infants. The result is in contrast
    to previous reports where nHFOV was applied at higher airway
    levels compared with nCPAP. Although the author provided brief information about the trial in the paper, we have the following questions about the details of the trial.
    1. How was the mean airway pressure (MAP) titrated in the two sequences?
    According to the paper, the range of MAPs applied in the two sequences were (5-8cmH2O)and (5-7cmH2O)respectively. The authors emphasized that the MAPs applied to nHFOV and nCPAP are equal, but it is not clear how was the MAP titrated (within the range) in the two sequences. Similar to what is done in invasive high frequency oscillatory ventilation, The MAP applied in nHFOV should be tit...

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  • End-expiratory pressure during the respiratory transition: a more complex tale?

    Dear Editors,
    I read with interest the review article of Martherus and co-workers entitled ‘Supporting breathing of preterm infants at birth: a narrative review’. Despite the ongoing focus on the respiratory transition at birth, clinical strategies that improve outcome are lacking. As such the authors should be congratulated on this timely review. As they emphasise, there is still a dearth of human data, and much of the literature regarding pressure strategies at birth remains in the domain of preclinical studies. The authors thus appropriately focused on the preclinical literature with regards to CPAP and PEEP levels, acknowledging that end-expiratory pressure remains the foundation of respiratory support. Table 1 and the accompanying text unfortunately do not fully achieve the authors stated aims of providing a summary of ‘the currently available literature’ concerning the ‘effect of different CPAP strategies in the very preterm lung at birth.’ Whilst this section provides a nice summary of six worthy studies arising predominantly from the authors’ own lab it cannot be considered inclusive or complete.

    The authors suggest that PEEP titration maybe useful during the respiratory transition. In 2014 we were the first to report the use of a high PEEP titration strategy at birth in preterm lambs, providing an escalating and then de-escalating PEEP (dynamic) strategy with transient PEEP levels up to 20 cmH2O. We demonstrated improved oxygenation and lung mechanic...

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