We would like to thank Miller et al for their interest in our recently published review and their responding letter to the editor. The first concern is combining RCTs and cohort studies. We agree that classic Cochrane methods advocate combining only same study designs in a meta-analysis. However, there is also an alternative viewpoint. Appropriate integration of randomized and observational cohort studies may offer opportunities to provide more timely, comprehensive, and generalizable evidence about the medical intervention1. To date, the majority of human milk studies on bronchopulmonary dysplasia (BPD) have been observational cohort studies. Generalizing extensive perspective is motivation for combining randomized and non-randomized evidence in a meta-analysis2. In our review, to detect the possibility of incorporating randomized and observational cohort studies, we assessed the statistic heterogeneity between cohort studies and randomized studies. The test for subgroup differences has been shown in table 3, which demonstrated the statistic heterogeneity (I2 and P values) is generally low. This gave a plausible reason to pool observational and randomized studies in our review. In fact, combining observational and randomized studies has been also performed in a similarly themed review for preventing BPD, when authors compared raw mother’s own milk with pasteurized mother’s own milk3.
The second concern from Miller et al was how to interpret the out...
We would like to thank Miller et al for their interest in our recently published review and their responding letter to the editor. The first concern is combining RCTs and cohort studies. We agree that classic Cochrane methods advocate combining only same study designs in a meta-analysis. However, there is also an alternative viewpoint. Appropriate integration of randomized and observational cohort studies may offer opportunities to provide more timely, comprehensive, and generalizable evidence about the medical intervention1. To date, the majority of human milk studies on bronchopulmonary dysplasia (BPD) have been observational cohort studies. Generalizing extensive perspective is motivation for combining randomized and non-randomized evidence in a meta-analysis2. In our review, to detect the possibility of incorporating randomized and observational cohort studies, we assessed the statistic heterogeneity between cohort studies and randomized studies. The test for subgroup differences has been shown in table 3, which demonstrated the statistic heterogeneity (I2 and P values) is generally low. This gave a plausible reason to pool observational and randomized studies in our review. In fact, combining observational and randomized studies has been also performed in a similarly themed review for preventing BPD, when authors compared raw mother’s own milk with pasteurized mother’s own milk3.
The second concern from Miller et al was how to interpret the outcome when the evidence from randomized and observational cohort studies were inconsistent. Miller et al stated that “the overall protective effect is driven by the cohort studies alone” in our review. However, this is not the case. In table 3, subgroup of RCT alone in all comparison showed a non-statistically significant trend towards protective effect of human milk on BPD. This meant the overall protective effect was not only driven by the cohort studies, but also attributed to the RCTs. RCTs undisputedly are on a higher level than observational studies. On the other hand, some of our most effective therapies are only supported by ‘lower-level’ observational studies, especially when the evidence from RCT is rare4. As conclusions in our review, we explicitly acknowledge the weakness of the evidence and that more RCTs are needed. A recent review for donor human milk on BPD also highlighted the benefit effect of human milk from observational studies, even though the effect from RCTs was not significant3.
Since neonates often received feeding with partial human milk due to a variety of reasons, paediatrician and parents pay close attention to the possible benefits of partial human milk feeding. One important aim of our review is to provide an overview of different portion/extent of human milk on BPD. In this setting, there are unavoidable overlaps in six categories: exclusive human milk (100% human milk), mainly human milk (50%≤human milk feeding<100%) and any human milk (0<human milk feeding≤100%); exclusive formula (100% formula feeding), mainly formula (50%≤formula feeding<100%) and any formula (0<formula feeding≤100%). A systematic review for human milk on retinopathy of prematurity also adopted the same method using replication of data 5.
We tried to avoid overlap by redefining two categories in our study to: any human milk (0<human milk feeding<50%) and any performed formula (0<human milk feeding<50%). Interestingly, our new meta-analysis only showed benefit from the comparision of exclusive human milk versus exclusive formula group [OR 0.78 (95% confidence interval 0.68 to 0.88)]. There was no statistical effect for other comparisons. Most comparisons included only one or two small studies. Overall, although we could not draw a definitive conclusion for maternal milk on BPD, limited evidence suggests further studies are necessary.
Competing interests None declared.
Reference
1. Cameron C, Fireman B, Hutton B, et al. Network meta-analysis incorporating randomized controlled trials and non-randomized comparative cohort studies for assessing the safety and effectiveness of medical treatments: challenges and opportunities. Systematic reviews 2015; 4: 147.
2. Verde PE, Ohmann C. Combining randomized and non-randomized evidence in clinical research: a review of methods and applications. Research synthesis methods 2015; 6: 45-62.
3. Villamor-Martinez E, Pierro M, Cavallaro G, et al. Donor human milk protects against bronchopulmonary dysplasia: a systematic review and meta-analysis. Nutrients 2018; 10: 238.
4. Verd S, Ginovart G. Human milk is perhaps the single most under-rated strategy to prevent bronchopulmonary dysplasia. Archives of disease in childhood Fetal and neonatal edition 2018 103: F599-f600.
5. Zhou J, Shukla VV, John D, et al. Human milk feeding as a protective factor for retinopathy of prematurity: a meta-analysis. pediatrics 2015; 136: e1576-86.
We thank Ovali et al for their interest in our paper. They emphasise that BPD results from a multifactorial process and has wide variation in severity. We agree that basing the prediction of BPD solely on ventilatory requirement at one week of age would not identify all cases of BPD, as demonstrated by the low sensitivity of 67% demonstrated in our study.[1] The high sensitivity of ventilation at one week of age in predicting the development of BPD (99%), however, means that it could facilitate counselling of parents and act as a screening tool to identify candidates for future trials of therapeutic interventions to prevent BPD.
[1] Hunt K, Dassios T, Ali K, et al. Prediction of bronchopulmonary dysplasia development. Arch Dis Child Fetal Neonatal Ed 2018 [Epub ahead of print].
I wish to comment about the outcomes you have selected for your study on gastroschisis and in particular caution against the use of 'primary closure' as an outcome at all. There are a number of reasons for this. Firstly, implicit in the use of primary closure as an outcome is a belief that it is either a good or bad thing. The literature would not support that either delayed closure or primary closure is superior, therefore it is impossible to know how to interpret a higher (or lower) rate of primary closure following either Caesarian section or vaginal delivery. Is a higher rate of primary closure good or bad? Secondly, the increasing use by paediatric surgeons of the preformed silo to manage return of the visceral contents to the abdominal cavity means that the closure technique may be prescribed rather than one that is dependent on other factors (such as mode of delivery). Its relevance therefore as an outcome is highly questionable.
I note also that you encountered 'differences in definition of outcomes, choice of outcome measures and variation in reporting methods'. Such difficulties can be a real challenge in the context of a meta-analysis and preclude accurate evidence synthesis. One proposed way to address this challenge is the development and use of a Core Outcome Set. A Core Outcome Set is a set of outcomes that has been derived through consensus methodology across stakeholder groups as being the most important outcomes to measure in re...
I wish to comment about the outcomes you have selected for your study on gastroschisis and in particular caution against the use of 'primary closure' as an outcome at all. There are a number of reasons for this. Firstly, implicit in the use of primary closure as an outcome is a belief that it is either a good or bad thing. The literature would not support that either delayed closure or primary closure is superior, therefore it is impossible to know how to interpret a higher (or lower) rate of primary closure following either Caesarian section or vaginal delivery. Is a higher rate of primary closure good or bad? Secondly, the increasing use by paediatric surgeons of the preformed silo to manage return of the visceral contents to the abdominal cavity means that the closure technique may be prescribed rather than one that is dependent on other factors (such as mode of delivery). Its relevance therefore as an outcome is highly questionable.
I note also that you encountered 'differences in definition of outcomes, choice of outcome measures and variation in reporting methods'. Such difficulties can be a real challenge in the context of a meta-analysis and preclude accurate evidence synthesis. One proposed way to address this challenge is the development and use of a Core Outcome Set. A Core Outcome Set is a set of outcomes that has been derived through consensus methodology across stakeholder groups as being the most important outcomes to measure in research related to a condition. The concept being that if all studies of a condition use a core outcome set then it is much easier to perform meta-analysis reliably. Other benefits include being more certain that the most important outcomes (as defined by a range of stakeholder groups) are being measured and reported.
We have recently developed a core outcome set for gastroschisis (Allin et al Arch Dis Child Fetal Neonatal Ed 2018 doi: 10.1136/archdischild-2017-314560) and would like to bring this to your and other researchers' attention. We believe it may help with some of the difficulties you have encountered in evidence synthesis and will provide a framework for other researchers when selecting which outcomes to measure in future studies of infants with gastroschisis.
We would like to thank Dr. Hutchon for his considered letter and for highlighting a number of important points. We very much acknowledge his experience in the area of cord management at the time of delivery and his ongoing endeavours to advocate for appropriate cord management at the time of delivery(1). He correctly notes that there is no current formal policy for cord management at delivery for term newborn infants in our institution, which undoubtedly results in variability in practice. In a recently completed prospective study evaluating cardiac output in healthy term infants, we have noted that approximately one third of infants had early cord clamping and two thirds some form of placental transfusion, either as delayed or milking. Whilst we cannot be certain or draw any definitive inferences, it is likely that this same variability exits in our cohort of patients. The point related to ‘immediate transfer’ to the resuscitaire may be somewhat misleading. This relates to once the cord is clamped, and not that the cord was immediately clamped in each case(2). We acknowledge that this terminology may be confusing, and therefore cannot concur that our results relate to early cord clamping alone. It is also important to highlight that all our newborns were spontaneously breathing at delivery and did not require any assistance with adaptation.
He makes a very valid comparison with oxygen saturation values in term infants highlighti...
We would like to thank Dr. Hutchon for his considered letter and for highlighting a number of important points. We very much acknowledge his experience in the area of cord management at the time of delivery and his ongoing endeavours to advocate for appropriate cord management at the time of delivery(1). He correctly notes that there is no current formal policy for cord management at delivery for term newborn infants in our institution, which undoubtedly results in variability in practice. In a recently completed prospective study evaluating cardiac output in healthy term infants, we have noted that approximately one third of infants had early cord clamping and two thirds some form of placental transfusion, either as delayed or milking. Whilst we cannot be certain or draw any definitive inferences, it is likely that this same variability exits in our cohort of patients. The point related to ‘immediate transfer’ to the resuscitaire may be somewhat misleading. This relates to once the cord is clamped, and not that the cord was immediately clamped in each case(2). We acknowledge that this terminology may be confusing, and therefore cannot concur that our results relate to early cord clamping alone. It is also important to highlight that all our newborns were spontaneously breathing at delivery and did not require any assistance with adaptation.
He makes a very valid comparison with oxygen saturation values in term infants highlighting the differences in oxygen saturation values between the Australian (3)and Leiden studies(4), attributing this difference to the impact of delayed cord clamping. It is interesting to note that there was a higher degree of bradycardia less than 80bpm in the Leiden cohort who received delayed cord clamping(4). A recent single centre study performed in Melbourne by Blank et al provides even greater clarity on respiratory adaptation(5). They evaluated similar respiratory variables to our measurements in a cohort of term infants, delivered both vaginally and by caesarean section. They did not identify any difference in respiratory variables between spontaneously breathing term infants based on mode of delivery. This is interesting when one considers that their hospital policy mandates caesarean delivered babies have immediate clamping and vaginally delivered have delayed clamping performed. This would suggest that in healthy term infants who do not require any respiratory support at birth, the timing of cord clamping results in no obvious difference in immediate respiratory variables over the first 10 mins of life. However this does not imply that delayed cord clamping has no immediate benefits on babies who may need support during this period of adaptation, and future work in this area is certainly warranted.
Eugene Dempsey and Daragh Finn
References
1. Hutchon D, Bettles N. Motherside care of the term neonate at birth. Matern Health Neonatol Perinatol. 2016;2:5.
2. Finn D, De Meulemeester J, Dann L, Herlihy I, Livingstone V, Boylan GB, et al. Respiratory adaptation in term infants following elective caesarean section. Arch Dis Child Fetal Neonatal Ed. 2018;103(5):F417-F21.
3. Dawson JA, Kamlin CO, Vento M, Wong C, Cole TJ, Donath SM, et al. Defining the reference range for oxygen saturation for infants after birth. Pediatrics. 2010;125(6):e1340-7.
4. Smit M, Dawson JA, Ganzeboom A, Hooper SB, van Roosmalen J, te Pas AB. Pulse oximetry in newborns with delayed cord clamping and immediate skin-to-skin contact. Arch Dis Child Fetal Neonatal Ed. 2014;99(4):F309-14.
5. Blank DA, Gaertner VD, Kamlin COF, Nyland K, Eckard NO, Dawson JA, et al. Respiratory changes in term infants immediately after birth. Resuscitation. 2018;130:105-10.
To the editor;
We have read the study of Hunt et al. describing the prediction of bronchopulmonary dysplasia (BPD) development at 1 week of age. (1). As it is very well known, BPD is a multifactorial disease with different clinical forms such as mild, moderate and severe. Early prediction of the disease is a clinically significant issue, such that early preventive measures may be taken, especially in cases with high risk. In our opinion, basing the prediction of BPD only on the ventilation requirement at 1 week of age is not appropriate. Respiratory distress syndrome and mechanical ventilation are important factors in the development of BPD but mechanical ventilation need is not sufficent enough for prediction in a disease with many risk factors. We had developed a simple clinical scoring system for the prediction of BPD, which takes into account the birthweight, gestational age, gender, hemodynamically signifiicant patent ductus arteriosus (HsPDA), respiratory distress syndrome, hypotension and intraventricular hemorrhage, at 72 hours of postnatal age (2). A score of less than 4 was considered as low, 4-6 as low intermediate, 7-9 as high intermediate and a score of above 9 was considered as high risk, in order to optimize the predictive values of lowest and highest categories. Among these parameters, HsPDA was the most significant one. The receiver operator curves (ROC) was 0.930, the negative predictive value of a score less than 4 were 95,9 whereas a positive pre...
To the editor;
We have read the study of Hunt et al. describing the prediction of bronchopulmonary dysplasia (BPD) development at 1 week of age. (1). As it is very well known, BPD is a multifactorial disease with different clinical forms such as mild, moderate and severe. Early prediction of the disease is a clinically significant issue, such that early preventive measures may be taken, especially in cases with high risk. In our opinion, basing the prediction of BPD only on the ventilation requirement at 1 week of age is not appropriate. Respiratory distress syndrome and mechanical ventilation are important factors in the development of BPD but mechanical ventilation need is not sufficent enough for prediction in a disease with many risk factors. We had developed a simple clinical scoring system for the prediction of BPD, which takes into account the birthweight, gestational age, gender, hemodynamically signifiicant patent ductus arteriosus (HsPDA), respiratory distress syndrome, hypotension and intraventricular hemorrhage, at 72 hours of postnatal age (2). A score of less than 4 was considered as low, 4-6 as low intermediate, 7-9 as high intermediate and a score of above 9 was considered as high risk, in order to optimize the predictive values of lowest and highest categories. Among these parameters, HsPDA was the most significant one. The receiver operator curves (ROC) was 0.930, the negative predictive value of a score less than 4 were 95,9 whereas a positive predictive values of a score more than 9 was 100. The validation of the results have yielded similar data. Other scoring systems may be found in the literature. Therefore we believe that the findings of Hunt et al should be interpreted with caution and more studies should be performed on the subject.
1) Hunt KA, Dassios T, Ali K, et al. Arch Dis Child Fetal neonatal Ed. Epub ahead of print, 2018; 18 October, doi: 10.1136/archdischild-2018-315343
2) Gürsoy T, Hayran M, Derin H, Ovali, F. A clinical scoring system to predict the development of bronchopulmonary dysplasia. Am J Perinatol 2015; 32(7): 659-66
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...
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 surfactant and invasive ventilation, the reason for which is unclear.
Authors used FiO2 alone as a criterion for defining CPAP failure and positive end-expiratory pressure (PEEP) level was not considered. In such cases, many babies who can be managed by increasing PEEP may have got intubated even without adequate recruitment leading to increased intubation rates. This may explain the increased CPAP failure rates in the study population as compared to the historical cohort. On careful analysis of CPAP failure cases, the mean PEEP pressure was 6 cm only, which supports the above hypothesis.
Although, the trial intended to see the effect on intubation and mechanical ventilation, both of which have a direct effect on bronchopulmonary dysplasia (BPD) rates, the better primary outcome would have been the incidence of BPD.
Surprisingly the cesarean delivery rates very high in the study population.
Competing interests: None
Source of funding: None
References:
1. Minocchieri S, Berry CA, Pillow JJ. Nebulised surfactant to reduce severity of respiratory distress: a blinded, parallel, randomised controlled trial. Archives of Disease in Childhood - Fetal and Neonatal Edition. Published Online First: 26 July 2018. doi:10.1136/archdischild-2018-315051
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.
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.
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.
We furthermore agree with Zhu et al. that careful consideration has to be given to the individual significance of an intervention free interval in between study periods when planning a cross-over trial.3 However, there is an incongruence across cross-over trials on the use of washout phases and the issue of carry-over effects.4 As detailed in the manuscript, there was no washout phase between both study periods since a wash out in the classical meaning (omission of respiratory support) was not feasible in our trial. Even so, we calculated the carry-over effect for any outcome parameter and found none (table 2).1
We thank Zhu et al for their comments and hope our reply clarified those important aspects to the reader.
References:
1 Klotz D, Schneider H, Schumann S, et al. Non-invasive high-frequency oscillatory ventilation in preterm infants: a randomised controlled cross-over trial. Arch Dis Child Fetal Neonatal Ed 2018;103:F1–F5 . doi: 10.1136/archdischild-2017-313190
2 Beltempo M, Isayama T, Vento M, et al. Respiratory Management of Extremely Preterm Infants: An International Survey. Neonatology 2018;114:28–36 . doi: 10.1159/000487987
3 Wellek S, Blettner M. On the proper use of the crossover design in clinical trials: part 18 of a series on evaluation of scientific publications. Dtsch Arztebl Int 2012; 109:276–281. doi: 10.3238/arztebl.2012.0276
4 Mills EJ, Chan A-W, Wu P, et al. Design, analysis, and presentation of crossover trials. Trials 2009;10:27. doi: 10.1186/1745-6215-10-27
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...
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 national neonatal data and a mature benchmarking system, is well set up for collaborative neonatal quality improvement. Professional organisations now need to actively promote collaboration by bringing together clinical leaders focused on excellence, encouraging neonatal units to work together, and facilitating a national community of learning. This might be the missing link to producing a step change in the quality of neonatal care.
1. Frankel A, Haraden C, Federico F, Safe LJAF, White EC. A Framework for Safe, Reliable, and Effective Care. Cambridge, MA; 2017.
2. The British Association of Perinatal Medicine. Neonatal Service Quality Indicators. London; 2017. https://www.bapm.org/NSQI
3. ØVretveit J, Bate P, Cleary P, Cretin S, Gustafson D, McInnes K, et al. Quality collaboratives: lessons from research. Qual Saf Health Care [Internet]. 2002;11(4):345–51. Available from: http://www.ncbi.nlm.nih.gov/pubmed/12468695%5Cnhttp://www.pubmedcentral....
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...
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 hormonal adjustments that occur during labour and vaginal delivery, so it is quite possible early cord clamping may have an even greater effect on the circulation and respiratory function after elective CS. Animal studies suggest that the effect of early cord clamping is less if respiration and the pulmonary circulation is established. No doubt many of these babies will have already taken their first breath before the cord was clamped, but we do not know how big an effect early clamping had on the overall results. Thus this study only contributes to our understanding of respiratory adaption of the term neonate following elective caesarean section and early cord clamping. ILCOR and NICE both recommend delayed cord clamping at the birth of all uncompromised term neonates. All babies born by elective CS should have delayed clamping if these guidelines are being followed and it is our understanding of the respiratory adaption of these babies which is still needed.
References
1. Finn D, De Meulemeester J, Dann L, et al Respiratory adaptation in term infants following elective caesarean section Archives of Disease in Childhood - Fetal and Neonatal Edition 2018;103:F417-F421.
In Reply
We would like to thank Miller et al for their interest in our recently published review and their responding letter to the editor. The first concern is combining RCTs and cohort studies. We agree that classic Cochrane methods advocate combining only same study designs in a meta-analysis. However, there is also an alternative viewpoint. Appropriate integration of randomized and observational cohort studies may offer opportunities to provide more timely, comprehensive, and generalizable evidence about the medical intervention1. To date, the majority of human milk studies on bronchopulmonary dysplasia (BPD) have been observational cohort studies. Generalizing extensive perspective is motivation for combining randomized and non-randomized evidence in a meta-analysis2. In our review, to detect the possibility of incorporating randomized and observational cohort studies, we assessed the statistic heterogeneity between cohort studies and randomized studies. The test for subgroup differences has been shown in table 3, which demonstrated the statistic heterogeneity (I2 and P values) is generally low. This gave a plausible reason to pool observational and randomized studies in our review. In fact, combining observational and randomized studies has been also performed in a similarly themed review for preventing BPD, when authors compared raw mother’s own milk with pasteurized mother’s own milk3.
The second concern from Miller et al was how to interpret the out...
Show MoreWe thank Ovali et al for their interest in our paper. They emphasise that BPD results from a multifactorial process and has wide variation in severity. We agree that basing the prediction of BPD solely on ventilatory requirement at one week of age would not identify all cases of BPD, as demonstrated by the low sensitivity of 67% demonstrated in our study.[1] The high sensitivity of ventilation at one week of age in predicting the development of BPD (99%), however, means that it could facilitate counselling of parents and act as a screening tool to identify candidates for future trials of therapeutic interventions to prevent BPD.
[1] Hunt K, Dassios T, Ali K, et al. Prediction of bronchopulmonary dysplasia development. Arch Dis Child Fetal Neonatal Ed 2018 [Epub ahead of print].
I wish to comment about the outcomes you have selected for your study on gastroschisis and in particular caution against the use of 'primary closure' as an outcome at all. There are a number of reasons for this. Firstly, implicit in the use of primary closure as an outcome is a belief that it is either a good or bad thing. The literature would not support that either delayed closure or primary closure is superior, therefore it is impossible to know how to interpret a higher (or lower) rate of primary closure following either Caesarian section or vaginal delivery. Is a higher rate of primary closure good or bad? Secondly, the increasing use by paediatric surgeons of the preformed silo to manage return of the visceral contents to the abdominal cavity means that the closure technique may be prescribed rather than one that is dependent on other factors (such as mode of delivery). Its relevance therefore as an outcome is highly questionable.
I note also that you encountered 'differences in definition of outcomes, choice of outcome measures and variation in reporting methods'. Such difficulties can be a real challenge in the context of a meta-analysis and preclude accurate evidence synthesis. One proposed way to address this challenge is the development and use of a Core Outcome Set. A Core Outcome Set is a set of outcomes that has been derived through consensus methodology across stakeholder groups as being the most important outcomes to measure in re...
Show MoreWe would like to thank Dr. Hutchon for his considered letter and for highlighting a number of important points. We very much acknowledge his experience in the area of cord management at the time of delivery and his ongoing endeavours to advocate for appropriate cord management at the time of delivery(1). He correctly notes that there is no current formal policy for cord management at delivery for term newborn infants in our institution, which undoubtedly results in variability in practice. In a recently completed prospective study evaluating cardiac output in healthy term infants, we have noted that approximately one third of infants had early cord clamping and two thirds some form of placental transfusion, either as delayed or milking. Whilst we cannot be certain or draw any definitive inferences, it is likely that this same variability exits in our cohort of patients. The point related to ‘immediate transfer’ to the resuscitaire may be somewhat misleading. This relates to once the cord is clamped, and not that the cord was immediately clamped in each case(2). We acknowledge that this terminology may be confusing, and therefore cannot concur that our results relate to early cord clamping alone. It is also important to highlight that all our newborns were spontaneously breathing at delivery and did not require any assistance with adaptation.
He makes a very valid comparison with oxygen saturation values in term infants highlighti...
Show MoreTo the editor;
Show MoreWe have read the study of Hunt et al. describing the prediction of bronchopulmonary dysplasia (BPD) development at 1 week of age. (1). As it is very well known, BPD is a multifactorial disease with different clinical forms such as mild, moderate and severe. Early prediction of the disease is a clinically significant issue, such that early preventive measures may be taken, especially in cases with high risk. In our opinion, basing the prediction of BPD only on the ventilation requirement at 1 week of age is not appropriate. Respiratory distress syndrome and mechanical ventilation are important factors in the development of BPD but mechanical ventilation need is not sufficent enough for prediction in a disease with many risk factors. We had developed a simple clinical scoring system for the prediction of BPD, which takes into account the birthweight, gestational age, gender, hemodynamically signifiicant patent ductus arteriosus (HsPDA), respiratory distress syndrome, hypotension and intraventricular hemorrhage, at 72 hours of postnatal age (2). A score of less than 4 was considered as low, 4-6 as low intermediate, 7-9 as high intermediate and a score of above 9 was considered as high risk, in order to optimize the predictive values of lowest and highest categories. Among these parameters, HsPDA was the most significant one. The receiver operator curves (ROC) was 0.930, the negative predictive value of a score less than 4 were 95,9 whereas a positive pre...
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.
Show MoreThe 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...
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.
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.
...Show MoreWe 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.
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...
Show MoreFinn 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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