Prophylactic surfactant nebulisation for the early aeration of the preterm lung: a randomised clinical trial

Electrical impedance tomography in neonates: a review

Appropriate interventions informed by real-time assessment of pulmonary function in mechanically ventilated critically ill neonates can reduce the incidence of bronchopulmonary dysplasia, pneumothorax, intraventricular hemorrhage and other complications of newborn life. The respiratory system in neonates is uniquely different from older children, and its physiological and anatomic attributes increase neonatal vulnerability to respiratory distress and eventual failure. While significant advancements have been made in developing respiratory support for neonates, such support is accompanied by inherent risks to their delicate lungs. Ventilator-associated lung injury poses a critical concern that can be potentially decreased with more precise, non-invasive, non-radiating, bedside methods for assessing neonatal pulmonary function in real time. Electrical impedance tomography (EIT) is one such tool, with immense potential for real-time pulmonary function monitoring in neonates. Still relatively new and in the earliest stages of clinical adoption, EIT use in neonatal critical care has been reported in several studies. This review discusses the basic features of EIT, its distinct advantages over traditional pulmonary function monitoring tools, the scope of its adoption in neonatal clinical practice, challenges associated with clinical adoption, and prospects for future applications. IMPACT: 1. Individualized care assisted by bedside pulmonary function monitoring can positively impact neonatal critical care and outcomes. 2. Electrical impedance tomography (EIT) has the potential to improve neonatal pulmonary function monitoring and treatment outcomes. 3. Electrical impedance tomography can be adopted as a part of routine neonatal respiratory critical care, especially in the population of patients most at risk for bronchopulmonary dysplasia and acute respiratory complications.

Comparative efficacy and safety of pulmonary surfactant delivery strategies in neonatal RDS: a network meta-analysis

PURPOSE

To compare five pulmonary surfactant (PS) administration strategies for neonates with respiratory distress syndrome (RDS), including intubation-surfactant-extubation (InSurE), thin catheter administration, laryngeal mask airway (LMA), surfactant nebulization (SN), and usual care, with a particular emphasis on the comparison of the LMA and SN with other strategies.

METHODS

We conducted a systematic search of MEDLINE, EMBASE, PUBMED, and Cochrane CENTRAL databases up to November 2023. Two authors independently conducted data extraction, and assessed bias using the Cochrane Risk of Bias Tool. Frequency-based random-effects network meta-analyses were executed.

RESULTS

A total of 36 trials and 4035 infants were included in the analysis. LMA (OR: 0.20, 95%CI: 0.09 to 0.42) and Less Invasive Surfactant Administration (LISA) (OR: 0.17, 95%CI: 0.09 to 0.32) significantly reduced intubation rates compared to usual care. SN had a higher intubation rate compared to LISA (OR: 3.36, 95%CI: 1.46 to 7.71) and LMA (OR: 2.92, 95%CI: 1.10 to 7.71). LMA had a higher incidence of BPD compared to LISA (OR: 2.59, 95%CI: 1.21 to 5.54). SN ranked second to LISA in preventing BPD and death, but its efficacy decreased after excluding high-risk studies. SN and LMA had the lowest incidence of adverse events during administration.SN had the highest likelihood of secondary administration. Most results were rated as low or very low quality, with findings related to SN significantly impacted by high-risk trials.

CONCLUSIONS

The thin catheter strategy minimized intubation risk and showed a better composite effect in reducing both mortality and BPD incidence. SN and LMA each showed safety and some clinical benefits in the subpopulations where they were studied, but their efficacy needs further validation through high-quality studies.

REGISTRATION

 This study was registered in PROSPERO (CRD42023463756).

Rescue nasopharyngeal tube for preterm infants non-responsive to initial ventilation after birth

BACKGROUND

Physiological changes during the insertion of a rescue nasopharyngeal tube (NPT) after birth are unclear.

METHODS

Observational study of very preterm infants in the delivery room. Data were extracted at predefined timepoints starting with first facemask placement after birth until 5 min after insertion of NPT. End-expiratory lung impedance (EELI), heart rate (HR) and SpO2/FiO2-ratio were analysed over time. Changes during the same time span of NIPPV via facemask and NIPPV via NPT were compared.

RESULTS

Overall, 1154 inflations in 15 infants were analysed. After NPT insertion, EELI increased significantly [0.33 AU/kg (0.19-0.57), p < 0.001]. Compared with the mask period, changes in EELI were not significantly larger during the NPT period [median difference (IQR) = 0.14 AU/kg (-0.14-0.53); p = 0.12]. Insertion of the NPT was associated with significant improvement in HR [52 (33-96); p = 0.001] and SpO2/FiO2-ratio [161 (69-169); p < 0.001] not observed during the mask period.

CONCLUSIONS

In very preterm infants non-responsive to initial facemask ventilation after birth, insertion of an NPT resulted in a considerable increase in EELI. This additional gain in lung volume was associated with an immediate improvement in clinical parameters. The use of a NPT may prevent intubation in selected non-responsive infants.

IMPACT

After birth, a nasopharyngeal tube may be considered as a rescue airway in newborn infants non-responsive to initial positive pressure ventilation via facemask. Although it is widely used among clinicians, its effect on lung volumes and physiological parameters remains unclear. Insertion of a rescue NPT resulted in a considerable increase in lung volume but this was not significantly larger than during facemask ventilation. However, insertion of a rescue NPT was associated with a significant and clinically important improvement in heart rate and oxygenation. This study highlights the importance of individual strategies in preterm resuscitation and introduces the NPT as a valid option.

Deciphering Mechanisms of Respiratory Fetal-to-Neonatal Transition in Very Preterm Infants

Rationale: The respiratory mechanisms of a successful transition of preterm infants after birth are largely unknown. Objectives: To describe intrapulmonary gas flows during different breathing patterns directly after birth. Methods: Analysis of electrical impedance tomography data from a previous randomized trial in preterm infants at 26-32 weeks gestational age. Electrical impedance tomography data for individual breaths were extracted, and lung volumes as well as ventilation distribution were calculated for end of inspiration, end of expiratory braking and/or holding maneuver, and end of expiration. Measurements and Main Results: Overall, 10,348 breaths from 33 infants were analyzed. We identified three distinct breath types within the first 10 minutes after birth: tidal breathing (44% of all breaths; sinusoidal breathing without expiratory disruption), braking (50%; expiratory brake with a short duration), and holding (6%; expiratory brake with a long duration). Only after holding breaths did end-expiratory lung volume increase: Median (interquartile range [IQR]) = 2.0 AU/kg (0.6 to 4.3), 0.0 (-1.0 to 1.1), and 0.0 (-1.1 to 0.4), respectively; P < 0.001]. This was mediated by intrathoracic air redistribution to the left and non-gravity-dependent parts of the lung through pendelluft gas flows during braking and/or holding maneuvers. Conclusions: Respiratory transition in preterm infants is characterized by unique breathing patterns. Holding breaths contribute to early lung aeration after birth in preterm infants. This is facilitated by air redistribution during braking/holding maneuvers through pendelluft flow, which may prevent lung liquid reflux in this highly adaptive situation. This study deciphers mechanisms for a successful fetal-to-neonatal transition and increases our pathophysiological understanding of this unique moment in life. Clinical trial registered with www.clinicaltrials.gov (NCT04315636).

Prophylactic Oropharyngeal Surfactant for Preterm Newborns at Birth: A Randomized Clinical Trial

Importance

Preterm newborns at risk of respiratory distress syndrome are supported with continuous positive airway pressure (CPAP). Many newborns worsen despite CPAP and are intubated for surfactant administration, an effective therapy for treatment of respiratory distress syndrome. Endotracheal intubation is associated with adverse effects. Pharyngeal administration of surfactant to preterm animals and humans has been reported as an alternative.

Objective

To assess whether giving prophylactic oropharyngeal surfactant to preterm newborns at birth would reduce the rate of intubation for respiratory failure.

Design, Setting, and Participants

This unblinded, parallel-group randomized clinical trial (Prophylactic Oropharyngeal Surfactant for Preterm Infants [POPART]) was conducted from December 17, 2017, to September 11, 2020, at 9 tertiary neonatal intensive care units in 6 European countries. Newborns born before 29 weeks of gestation without severe congenital anomalies, for whom intensive care was planned, were eligible for inclusion. The data were analyzed from July 27, 2022, to June 20, 2023.

Intervention

Newborns were randomly assigned to receive oropharyngeal surfactant at birth in addition to CPAP or CPAP alone. Randomization was stratified by center and gestational age (GA).

Main Outcomes and Measures

The primary outcome was intubation in the delivery room for bradycardia and/or apnea or in the neonatal intensive care unit for prespecified respiratory failure criteria within 120 hours of birth. Caregivers were not masked to group assignment.

Results

Among 251 participants (mean [SD] GA, 26 [1.5] weeks) who were well matched at study entry, 126 (69 [54.8%] male) with a mean (SD) birth weight of 858 (261) grams were assigned to the oropharyngeal surfactant group, and 125 (63 [50.4%] male) with a mean (SD) birth weight of 829 (253) grams were assigned to the control group. The proportion of newborns intubated within 120 hours was not different between the groups (80 [63.5%) in the oropharyngeal surfactant group and 81 [64.8%] in the control group; relative risk, 0.98 [95% CI, 0.81-1.18]). More newborns assigned to the oropharyngeal surfactant group were diagnosed with and treated for pneumothorax (21 [16.6%] vs 8 [6.4%]; P = .04).

Conclusions and Relevance

This randomized clinical trial found that administration of prophylactic oropharyngeal surfactant to newborns born before 29 weeks' GA did not reduce the rate of intubation in the first 120 hours of life. These findings suggest that administration of surfactant into the oropharynx immediately after birth in addition to CPAP should not be routinely used.

Trial Registration

EudraCT: 2016-004198-41.

Early prediction of pulmonary outcomes in preterm infants using electrical impedance tomography

Introduction

Electrical impedance tomography (EIT) allows assessment of ventilation and aeration homogeneity which may be associated with respiratory outcomes in preterm infants.

Methods

This was a secondary analysis to a recent randomized controlled trial in very preterm infants in the delivery room (DR). The predictive value of various EIT parameters assessed 30 min after birth on important respiratory outcomes (early intubation <24 h after birth, oxygen dependency at 28 days after birth, and moderate/severe bronchopulmonary dysplasia; BPD) was assessed.

Results

Thirty-two infants were analyzed. A lower percentage of aerated lung volume [OR (95% CI) = 0.8 (0.66-0.98), p = 0.027] as well as a higher aeration homogeneity ratio (i.e., more aeration in the non-gravity-dependent lung) predicted the need for supplemental oxygen at 28 days after birth [9.58 (5.16-17.78), p = 0.0028]. Both variables together had a similar predictive value to a model using known clinical contributors. There was no association with intubation or BPD, where numbers were small.

Discussion

In very preterm infants, EIT markers of aeration at 30 min after birth accurately predicted the need for supplemental oxygen at 28 days after birth but not BPD. EIT-guided individualized optimization of respiratory support in the DR may be possible.