Ventilation and respiratory outcome in extremely preterm infants: trends in the new millennium

Bronchopulmonary Dysplasia-Associated Pulmonary Hypertension: Basing Care on Physiology

Bronchopulmonary dysplasia (BPD) is the heterogeneous chronic lung developmental disease of prematurity, which is often accompanied by multisystem comorbidities. Pulmonary vascular disease and pulmonary hypertension (PH) contribute significantly to the pathogenesis and pathophysiology of BPD and dramatically influence the outcomes of preterm infants with BPD. When caring for those patients, clinicians should consider the multitude of phenotypic presentations that fall under the "BPD-PH umbrella," reflecting the need for matching therapies to specific physiologies to improve short- and long-term outcomes. Individualized management based on the patient's prenatal and postnatal risk factors, clinical course, and cardiopulmonary phenotype needs to be identified and prioritized to provide optimal care for infants with BPD-PH.

Pulmonary Hypertension in Established Bronchopulmonary Dysplasia: Physiologic Approaches to Clinical Care

Preterm infants with bronchopulmonary dysplasia (BPD) are prone to develop pulmonary hypertension (PH). Strong laboratory and clinical data suggest that antenatal factors, such as preeclampsia, chorioamnionitis, oligohydramnios, and placental dysfunction leading to fetal growth restriction, increase susceptibility for BPD-PH after premature birth. Echocardiogram metrics and serial assessments of NT-proBNP provide useful tools to diagnose and monitor clinical course during the management of BPD-PH, as well as monitoring for such complicating conditions as left ventricular diastolic dysfunction, shunt lesions, and pulmonary vein stenosis. Therapeutic strategies should include careful assessment and management of underlying airways and lung disease, cardiac performance, and systemic hemodynamics, prior to initiation of PH-targeted drug therapies.

Respiratory management of established severe bronchopulmonary dysplasia

Respiratory management of infants with established severe BPD is difficult and there is little evidence upon which to base decisions. Nonetheless, the physiology of severe BPD is well described with a predominantly obstructive pattern. This pulmonary dysfunction results in prolonged exhalatory time constants and thus ventilator management must be focused on maintaining adequate oxygenation and ventilation through achieving full exhalation. This approach is often difficult to maintain in acute care settings and a culture of chronic care focused on slow change and steady progress is imperative. Once respiratory stability is achieved, the focus should shift to growth and development and avoidance of care practices and medications that impair neurodevelopment.

State of the art on neonatal noninvasive respiratory support: How physiological and technological principles explain the clinical outcomes

Noninvasive respiratory support has gained significant popularity in neonatal units because of its potential to reduce lung injury associated with invasive mechanical ventilation. To minimize lung injury, clinicians aim to apply for noninvasive respiratory support as early as possible. However, the physiological background and the technology behind such support modes are not always clear, and many open questions remain regarding the indications of use and clinical outcomes. This narrative review discusses the currently available evidence for various noninvasive respiratory support modes applied in Neonatal Medicine in terms of physiological effects and indications. Reviewed modes include nasal continuous positive airway pressure, nasal high-flow therapy, noninvasive high-frequency oscillatory ventilation, nasal intermittent positive pressure ventilation (NIPPV), synchronized NIPPV and noninvasive neurally adjusted ventilatory assist. To enhance clinicians' awareness of each support mode's strengths and limitations, we summarize technical features related to the functioning mechanisms of devices and the physical properties of the interfaces commonly used for providing noninvasive respiratory support to neonates. We finally address areas of current controversy and suggest possible areas of research for implementing noninvasive respiratory support in neonatal intensive care units.

Laryngeal Mask Airway Clinical Use and Training: A Survey of North American Neonatal Health Care Professionals

OBJECTIVE

 The aim of this study was to explore North American neonatal health care professionals' (HCPs) experience, confidence, skill, and training with the laryngeal mask airway (LMA).

STUDY DESIGN

 This was a cross-sectional survey.

RESULTS

 The survey was completed by 2,159 HCPs from Canada and the United States. Seventy nine percent had no clinical experience with the LMA, and less than 20% considered the LMA an alternative to endotracheal intubation (EI). The majority had received LMA training; however, 28% of registered nurses, 18% of respiratory therapists, 17% of physicians, and 12% of midwives had never inserted an LMA in a mannequin. Less than a quarter of respondents agreed that the current biennial Neonatal Resuscitation Program instruction paradigm is sufficient for LMA training. All groups reported low confidence and skill with LMA insertion, and compared with all other groups, the respiratory therapists had the highest reported confidence and skill.

CONCLUSION

 This survey study, which is the first of its kind to include midwives, demonstrates that neonatal HCPs lack experience, confidence, skill, and training with the LMA, rarely use the device, and in general, do not consider the LMA as an alternative to EI. These findings contribute to, and support the findings of previous smaller studies, and in conjunction with the diminishing opportunities for EI, highlight the need for programs to emphasize the importance of the LMA for neonatal airway management and prioritize regular LMA training, with focus that parallels the importance placed on the skills of EI and mask ventilation.

KEY POINTS

· Lack of training for laryngeal mask airway use in neonatal resuscitation.. · Neonatal health care professionals rarely use the laryngeal mask airway as an alternate airway device.. · Neonatal health care professionals lack confidence and skill with the laryngeal mask airway..

Changes in ventilation modes in the last decade and their impact on the prevalence of bronchopulmonary dysplasia in preterm infants

BACKGROUND

Less invasive forms of ventilation have evolved aiming to decrease bronchopulmonary dysplasia (BPD) morbidity. It is unclear whether changes in ventilation practices have been associated with improvements in respiratory outcomes.

OBJECTIVE

To examine the changes in ventilation modes in preterm neonates between two periods during the last decade and their impact on BPD prevalence.

METHODS

A retrospective chart review of very low birth weight infants and those born at less than 32 weeks gestation hospitalized during two periods: the years 2012-2013 and 2018-2019. The primary outcome was the prevalence of BPD. Study variables included the mode and duration of ventilation, duration of oxygen need, and perinatal clinical parameters.

RESULTS

Four hundred eighty-one infants were enrolled. Between the two study periods, a significant increase was observed in invasive (33%-47%, p = 0.002), and noninvasive ventilation rates (44%-72%, p < 0.001). The average duration of noninvasive ventilation increased significantly (from 9.24 to 14.08 days, p = 0.016). The total duration of respiratory support remained unchanged. The overall prevalence of moderate and severe BPD at 36 weeks corrected age remained approximately 40% in preterm infants born at less than 28 weeks gestation.

CONCLUSION

The increasing use of non-invasive ventilation was not accompanied by a reduction in the use of invasive ventilation, nor by a reduced prevalence of BPD. The high prevalence of BPD remains a significant problem in extreme prematurity. Other interventions, in addition to less aggressive ventilation, need to be explored.

Instrumental dead space: A glass ceiling for extremely low birth weight preterm infants? A dead space washout bench study

BACKGROUND

When ventilating extremely low birth weight infants, clinicians face the problem of instrumental dead space, which is often larger than tidal volume. Hence, aggressive ventilation is necessary to achieve CO₂ removal. Continuous tracheal gas insufflation can wash out CO₂ from dead space and might also have an impact on O₂ and water vapor transport. The objective of this bench study is to test the impact of instrumental dead space on the transport of CO₂ , O₂ , and water vapor and the ability of continuous tracheal gas insufflation to remedy this problem during small tidal volume ventilation.

METHODS

A test-lung located in an incubator at 37°C was ventilated with pressure levels needed to reach different tidal volumes from 1.5 to 5 mL. End-tidal CO₂ at the test-lung exit, O₂ concentration, and relative humidity in the test-lung were measured for each tidal volume with and without a 0.2 L/min continuous tracheal gas insufflation flow.

RESULTS

CO₂ clearance was improved by continuous tracheal gas insufflation allowing a 28%-44% of tidal volume reduction. With continuous tracheal gas insufflation, time to reach desired O₂ concentration was reduced from 20% to 80% and relative humidity was restored. These results are inversely related to tidal volume and are particularly critical below 3 mL.

CONCLUSION

For the smallest tidal volumes, reduction of instrumental dead space seems mandatory for CO₂ , O₂ , and water vapor transfer. Continuous tracheal gas insufflation improved CO₂ clearance, time to reach desired O₂ concentration and humidification of airways and, thus, may be an option to protect lung development.

Caffeine and bronchopulmonary dysplasia: Clinical benefits and the mechanisms involved

Bronchopulmonary dysplasia (BPD) is a chronic respiratory disease that occurs during the neonatal period and is commonly associated with prematurity. This condition results in a severe economic burden on society and the families involved. Caffeine is used not only for the treatment of apnea in prematurity, but also for the prevention of BPD. There are multiple clinical benefits of caffeine treatment, including improved extubation success, a reduced duration of mechanical ventilation, improved lung function, and a reduction of patent ductus arteriosus requiring treatment. These clinical benefits of caffeine for the treatment of BPD are supported by both clinical trials and evidence from animal models. However, the mechanism by which caffeine protects against BPD remains unclear. Here, we review the clinical value of caffeine in the prevention of BPD and its potential mechanisms of action, including anti-inflammatory, antioxidant, antifibrotic, and antiapoptotic properties, the regulation of angiogenesis, and diuretic effects. Our aim is to provide a new theoretical basis for the clinical treatment of BPD.

Birth during on-call period: Impact of care organization on mortality and morbidity of very premature neonates

OBJECTIVES

The evidence that risks of morbidity and mortality are higher when very premature newborns are born during the on-call period is inconsistent. This study aimed to assess the impact of this situation among other determinants of outcomes, particularly newborn characteristics and care organization.

METHODS

Observational study including all infants born < 30 weeks' gestation in a French tertiary perinatal center between 2007 and 2020. On-call period corresponded to weekdays between 6:30 p.m. and 8:30 a.m., weekends, and public holidays. The primary endpoint was survival without severe morbidity, including grade 3-4 intraventricular hemorrhage (IVH), cystic periventricular leukomalacia, necrotizing enterocolitis, severe bronchopulmonary dysplasia (BPD), and severe retinopathy of prematurity. The relationship between admission and outcome was assessed by an adjusted odds ratio (aOR) on the propensity of being born during on-call period and expressed vs. weekday. Secondary analyses were carried out in extremely preterm newborns (<27 weeks' gestation), in cases of early death (within 7 days), and before (2007-2013, 51.5% of the cohort) vs. after (2014-2020, 48.5% of the cohort) the implementation of a pediatrician-nurse team dedicated to newborn care in the delivery room.

RESULTS

A total of 1,064 infants [27.9 (26.3; 28.9) weeks, 947 (760; 1,147) g] were included: 668 during the on-call period (63%) and 396 (37%) on weekdays. For infants born on weekdays, survival without severe morbidity was 54.5% and mortality 19.2%. During on-call, these rates were 57.3% [aOR 1.08 (0.84-1.40)] and 18.4% [aOR 0.93 (0.67-1.29)]. Comparable rates of survival without severe morbidity [aOR 1.42 (0.87-2.34)] or mortality [aOR 0.76 (0.47-1.22)] were observed in extremely preterm infants. The early death rate was 6.4% on weekdays vs. 8.2% during on-call [aOR 1.44 (0.84-2.48)]. Implementation of the dedicated team was associated with decreased rates of mortality [aOR 0.57 (0.38, 0.85)] and grade 3-4 IVH [aOR 0.48 (0.30, 0.75)], and an increased rate of severe BPD [aOR 2.16 (1.37, 3.41)], for infants born during on-call.

CONCLUSION

In this cohort, most births of very premature neonates occurred during the on-call period. A team dedicated to newborn care in the delivery room may have a favorable effect on the outcome of infants born in this situation.