Respiratory distress syndrome in preterm neonates in the era of precision medicine: A modern critical care-based approach

Structure and Function of Canine SP-C Mimic Proteins in Synthetic Surfactant Lipid Dispersions

Lung surfactant is a mixture of lipids and proteins and is essential for air breathing in mammals. The hydrophobic surfactant proteins B and C (SP-B and SP-C) assist in reducing surface tension in the lung alveoli by organizing the surfactant lipids. SP-B deficiency is life-threatening, and a lack of SP-C can lead to progressive interstitial lung disease. B-YL (41 amino acids) is a highly surface-active, sulfur-free peptide mimic of SP-B (79 amino acids) in which the four cysteine residues are replaced by tyrosine. Mammalian SP-C (35 amino acids) contains two cysteine-linked palmitoyl groups at positions 5 and 6 in the N-terminal region that override the β-sheet propensities of the native sequence. Canine SP-C (34 amino acids) is exceptional because it has only one palmitoylated cysteine residue at position 4 and a phenylalanine at position 5. We developed canine SP-C constructs in which the palmitoylated cysteine residue at position 4 is replaced by phenylalanine (SP-Cff) or serine (SP-Csf) and a glutamic acid-lysine ion-lock was placed at sequence positions 20-24 of the hydrophobic helical domain to enhance its alpha helical propensity. AI modeling, molecular dynamics, circular dichroism spectroscopy, Fourier Transform InfraRed spectroscopy, and electron spin resonance studies showed that the secondary structure of canine SP-Cff ion-lock peptide was like that of native SP-C, suggesting that substitution of phenylalanine for cysteine has no apparent effect on the secondary structure of the peptide. Captive bubble surfactometry demonstrated higher surface activity for canine SP-Cff ion-lock peptide in combination with B-YL in surfactant lipids than with canine SP-Csf ion-lock peptide. These studies demonstrate the potential of canine SP-Cff ion-lock peptide to enhance the functionality of the SP-B peptide mimic B-YL in synthetic surfactant lipids.

Ultrasound diagnosis and grading criteria of neonatal respiratory distress syndrome

Background: Respiratory distress syndrome (RDS) is a common critical lung disease in newborn infants, especially those in premature infants with higher mortality rate. Early and correct diagnosis is the key to improve its prognosis. Previously, the diagnosis of RDS mainly relied on chest X-ray (CXR) findings, and it has been graded into four stages based on the progression and severity of CXR changes. This traditional diagnosing and grading method may lead to high misdiagnosis rate or delayed diagnosis. Recently, using ultrasound to diagnose neonatal lung diseases and RDS is becoming increasingly popular, and the technology is gaining higher sensitivity and higher specificity. The management of RDS under lung ultrasound (LUS) monitoring has achieved significant results, reducing the misdiagnosis rate of RDS, thereby reducing the probability of mechanical ventilation and the use of exogenous pulmonary surfactant, and making the success rate of treatment of RDS up to 100%.Objective: The purpose of the article was to introduce the ultrasound grading methods and criteria of RDS, in order to promote the application of LUS in the diagnosis and treatment of RDS.Methods: Literature (in English and Chinese) on the use of ultrasound in the diagnosis of neonatal RDS between 2008 and 2022 was selected for inclusion in this study.Results: From the collected literature, the use of ultrasound in the diagnosis of RDS is increasing, and people's understanding of the ultrasound imaging findings of RDS is also changing. Among them, the research on ultrasound grading of RDS is the latest progress.Conclusion: Ultrasound is accurate and reliable in the diagnosis and differential diagnosis of RDS. It is of great clinical value to master the ultrasound diagnosis and grading criteria of RDS.

Respiratory distress syndrome prediction at birth by optical skin maturity assessment and machine learning models for limited-resource settings: a development and validation study

Background

A handheld optical device was developed to evaluate a newborn's skin maturity by assessing the photobiological properties of the tissue and processing it with other variables to predict early neonatal prognosis related to prematurity. This study assessed the device's ability to predict respiratory distress syndrome (RDS).

Methods

To assess the device's utility we enrolled newborns at childbirth in six urban perinatal centers from two multicenter single-blinded clinical trials. All newborns had inpatient follow-up until 72 h of life. We trained supervised machine learning models with data from 780 newborns in a Brazilian trial and provided external validation with data from 305 low-birth-weight newborns from another trial that assessed Brazilian and Mozambican newborns. The index test measured skin optical reflection with an optical sensor and adjusted acquired values with clinical variables such as birth weight and prenatal corticoid exposition for lung maturity, maternal diabetes, and hypertensive disturbances. The performance of the models was evaluated using intrasample k-parts cross-validation and external validation in an independent sample.

Results

Models adjusting three predictors (skin reflection, birth weight, and antenatal corticoid exposure) or five predictors had a similar performance, including or not maternal diabetes and hypertensive diseases. The best global accuracy was 89.7 (95% CI: 87.4 to 91.8, with a high sensitivity of 85.6% (80.2 to 90.0) and specificity of 91.3% (95% CI: 88.7 to 93.5). The test correctly discriminated RDS newborns in external validation, with 82.3% (95% CI: 77.5 to 86.4) accuracy. Our findings demonstrate a new way to assess a newborn's lung maturity, providing potential opportunities for earlier and more effective care.

Trial registration

RBR-3f5bm5 (online access: http://www.ensaiosclinicos.gov.br/rg/RBR-3f5bm5/), and RBR-33mjf (online access: https://ensaiosclinicos.gov.br/rg/RBR-33rnjf/).

Effect of different ventilation methods combined with pulmonary surfactant on neonatal acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome precipitates is widespread pulmonary injury in impacted individuals, the neonatal respiratory distress syndrome (NRDS), primarily observed in preterm infants, represents a prevalent critical condition in neonatal clinical settings.

AIM

To investigate the clinical efficacy of various ventilation strategies combined with pulmonary surfactant (PS) therapy in the treatment of NRDS.

METHODS

A total of 20 neonates diagnosed with respiratory distress syndrome, admitted between May 2021 and June 2022, were randomly assigned to either a research group or a control group. Neonates in the research group received treatment involving high-frequency oscillatory ventilation (HFOV) in conjunction with PS. In contrast, neonates in the control group were administered either controlled mechanical ventilation or synchronous intermittent mandatory ventilation, combined with PS. Arterial blood samples from the neonates in both groups were collected before treatment, as well as 6 h, 12 h, 24 h, and 48 h post-treatment. These samples underwent blood gas analysis, with measurements taken for pH value, partial pressures of oxygen (O2) and carbon dioxide. Concurrently, data was collected on the duration of ventilator use, length of hospitalization time, O2 treatment time, treatment outcomes, and complications of the ventilator.

RESULTS

From 6-48 h post-treatment, both groups demonstrated significant improvements in arterial blood pH and oxygen partial pressure, along with a significant decrease in carbon dioxide partial pressure compared to pre-treatment values (P < 0.05). Although these changes progressed over time, there were no significant differences between the two groups (P > 0.05). However, the research group had significantly lower X-ray scores, shorter hospitalization time, and less time on O2 therapy compared to the control group (P < 0.05). Mortality rates were similar between the two groups (P > 0.05), but the research group had a significantly lower incidence of complications (P < 0.05).

CONCLUSION

The integration of HFOV combine with PS has proven to effectively expedite the treatment duration, decrease the occurrence of complications, and secure the therapeutic efficacy in managing NRDS.

Unraveling the Efficacy of Therapeutic Interventions for Short Cervix: Insights from a Retrospective Study for Improved Clinical Management

Background and Objectives: Preterm birth (PTB) is associated with important neonatal mortality and morbidity. The aim of this study was to retrospectively evaluate the average treatment effects on the treated and the efficacity of various therapeutic interventions for PTB in a cohort of patients with singleton pregnancies and short cervical lengths. Materials and Methods: This observational retrospective study included 1146 singleton pregnancies at risk of PTB that were segregated into the following groups: intravaginal progesterone (group 1), Arabin pessary (group 2), McDonald cerclage (group 3), intravaginal progesterone and Arabin pessary (group 4), and intravaginal progesterone and cerclage (group 5). Their treatment effects were evaluated and compared. Results: All evaluated therapeutic interventions significantly reduced the occurrence of late and early preterm births. The risk of late and early PTB was lowered for those pregnant patients who received progesterone and pessaries or progesterone and cerclage in comparison with those who received only progesterone. The extremely PTB risk of occurrence was significantly lowered only by the administration of progesterone in association with cervical cerclage in comparison with progesterone monotherapy. Conclusions: The combined therapeutic interventions had the highest efficacy in preventing preterm birth. An individualized evaluation is needed to establish the best therapeutic approach in particular cases.

Respiratory and haemodynamic effects of 6h-pronation in neonates recovering from respiratory distress syndrome, or affected by acute respiratory distress syndrome or evolving bronchopulmonary dysplasia: a prospective, physiological, crossover, controlled cohort study

BACKGROUND

Pronation ameliorates oxygenation in adults with acute respiratory distress syndrome (ARDS); the effect in neonates with ARDS or other types of respiratory failure is unknown. We aimed to verify if pronation has similar respiratory and haemodynamic effects in three common types of neonatal respiratory failure.

METHODS

Prospective, physiologic, crossover, quasi-randomised, controlled cohort study performed in a tertiary academic neonatal intensive care unit. We enrolled neonates with: 1) recovering respiratory distress syndrome (RDS, mild restrictive pattern); 2) neonatal ARDS (NARDS, severe restrictive pattern); or 3) evolving bronchopulmonary dysplasia (BPD), that is chronic pulmonary insufficiency of prematurity (mixed restrictive/obstructive pattern). Neonates with other lung disorders, malformations or haemodynamic impairment were excluded. Patients were started prone or supine and then shifted to the alternate position for 6h; measurements were performed after 30' of "wash out" from the positioning and at the end of 6h period. Primary outcomes were respiratory (PtcCO_2, modified ventilatory index, PtcO₂/FiO₂, SpO₂/FiO₂, oxygenation index, ultrasound-assessed lung aeration) and haemodynamic (perfusion index, heart rate, arterial pressure, cardiac output) parameters.

FINDINGS

Between May 1st, 2019, and May 31st, 2021, 161 participants were enrolled in this study, and included in the final analysis. Pronation improved gas exchange and lung aeration (p always <0.01) and these effects were overturned in the alternate position, except for lung aeration in NARDS where the improvement persisted. The effects were greater in patients recovering from RDS than in those with evolving BPD than in those with NARDS, in this order (p always <0.01). Pronation produced a net recruitment as lung ultrasound score decreased in patients shifted from supine (16.9 (standard deviation: 5.8)) to prone (14.1 (standard deviation: 3.3), p < 0.01) and this reduction correlated with oxygenation improvement. Haemodynamic parameters remained within normal ranges.

INTERPRETATION

6h-pronation can be used to improve gas exchange and lung aeration in neonates with recovering RDS, evolving BPD or NARDS without relevant haemodynamic effects.

FUNDING

None.

Comparative effectiveness of calfactant and beractant in neonatal respiratory distress syndrome: A systemic review and meta-analysis

INTRODUCTION

Animal derived surfactants are considered to be the standard treatment for neonatal respiratory distress syndrome (NRDS). However, their comparative effectiveness remains inconclusive given the multiple prior studies with inconsistent results. Therefore, we conducted a systematic review and meta analysis to compare the effectiveness of two animal extract surfactants (calfactant and beractant) for the management of NRDS.

METHODS

We searched Pubmed, Scopus, and Google Scholar for studies comparing efficacy of calfactant and beractant for the treatment of NRDS. Mean differences (MD) and risk ratios (RR) with a 95% confidence interval (CI) were calculated using Review Manager.

RESULT

We found no significant difference between calfactnat and beractant groups in the primary outcomes: neonatal mortality before the age of 28 days (RR = 1.19, 95% CI = 0.97-1.46, p = 0.09), mortality before the hospital release (RR = 1.12, 95% Cl = 0.94-1.33, p = 0.22), oxygen requirement at 28 days of age (RR = 0.97, 95% CI = 0.90-1.05, p = 0.52), and death or oxygen need at 36 weeks postmenstrual age (RR = 0.99, 95% CI = 0.91-1.08, p = 0.81). The duration of supplementary oxygen was significantly lower in calfactant users (MD = -4.95, 95% CI = -7.60--2.30, p = 0.0002). Calfactant significantly lowered the duration of hospital stay, risk of pneumothorax and air leak syndrome whereas beractant users had lower risk of intraventricular hemorrhage (Grades 3 and 4).

CONCLUSION

There is no substantial difference in the efficacy of both surfactants in the prophylaxis and treatment of NRDS.

Application of ultrasonography in neonatal lung disease: An updated review

Lung disease is often life-threatening for both preterm and term newborns. Therefore, an accurate and rapid diagnosis of lung diseases in newborns is crucial, as management strategies differ with different etiologies. To reduce the risk of radiation exposure derived from the conventionally used chest x-ray as well as computed tomography scans, lung ultrasonography (LUS) has been introduced in clinical practice to identify and differentiate neonatal lung diseases because of its radiation-free characteristic, convenience, high accuracy, and low cost. In recent years, it has been proved that LUS exhibits high sensitivity and specificity for identifying various neonatal lung diseases. Here, we offer an updated review of the applications of LUS in neonatal lung diseases based on the reports published in recent years (2017 to present).

Exogenous pulmonary surfactant in COVID-19 ARDS. The similarities to neonatal RDS suggest a new scenario for an 'old' strategy

Acute respiratory distress syndrome (ARDS) related to SARS-CoV-2 infection has some unusual characteristics that differentiate it from the pathophysiology described in the more ‘typical’ ARDS. Among multiple hypotheses, a close similarity has been suggested between COVID-19 ARDS and neonatal respiratory distress syndrome (RDS). With this opinion paper, we investigated the pathophysiological similarities between infant respiratory diseases (RDS and direct neonatal ARDS (NARDS)) and COVID-19 in adults. We also analysed, for the first time, similarities in the response to exogenous surfactant administration in terms of improved static compliance in RDS and direct NARDS, and adult COVID-19 ARDS. In conclusion, we believe that if the pathological processes are similar both from the pathophysiological point of view and from the response in respiratory mechanics to a recruitment treatment such as surfactant, perhaps the latter could be considered a plausible option and lead to recruitment in clinical trials currently ongoing on patients with COVID-19.