Mesenchymal stem cells-based therapies for severe ARDS with ECMO: a review

Acute respiratory distress syndrome (ARDS) is the primary cause of respiratory failure in critically ill patients. Despite remarkable therapeutic advances in recent years, ARDS remains a life-threatening clinical complication with high morbidity and mortality, especially during the global spread of the coronavirus disease 2019 (COVID-19) pandemic. Previous studies have demonstrated that mesenchymal stem cell (MSC)-based therapy is a potential alternative strategy for the treatment of refractory respiratory diseases including ARDS, while extracorporeal membrane oxygenation (ECMO) as the last resort treatment to sustain life can help improve the survival of ARDS patients. In recent years, several studies have explored the effects of ECMO combined with MSC-based therapies in the treatment of ARDS, and some of them have demonstrated that this combination can provide better therapeutic effects, while others have argued that some critical issues need to be solved before it can be applied to clinical practice. This review presents an overview of the current status, clinical challenges and future prospects of ECMO combined with MSCs in the treatment of ARDS.

The association of IL-10-1082G/A gene polymorphism with the risk of acute lung injury/respiratory distress syndrome (ALI/RDS): A meta-analysis

BACKGROUND

Several records have reported that single nucleotide polymorphism (SNP) at the interleukin 10 (IL-10)-1082G/A locus affects the risk of acute lung injury/respiratory distress syndrome (ALI/RDS), but the exact association between them has not been elucidated.

OBJECTIVE

This systematic review aims to elucidate the relationship between SNP at the IL-10-1082G/A locus and susceptibility to ALI/RDS by the method of meta-analysis, to identify the early warning indicators of ALI/RDS.

METHODS

Studies on IL-10-1082G/A SNP associated with ALI/RDS were obtained by thorough retrieval of four English databases from each database construction to April 1, 2022. We processed the data using Stata 15.0 software.

RESULTS

Eight eligible records were entered into this meta-analysis. The pooled analysis demonstrated that SNP at the IL-10-1082G/A locus contributed to the risk of ALI/RDS in the allelic (G vs. A: OR= 0.74, 95%CI: 0.55∼0.98) and recessive gene models (Genotype GG vs. GA+AA: OR= 0.57, 95%CI: 0.35∼0.93). The subgroup analysis based on case type showed that SNP at IL-10-1082G/A locus contributed to the risk of neonatal respiratory distress syndrome (NRDS) under all the gene models (Allele G vs. A: OR= 0.45, 95%CI: 0.29∼0.72; Genotype GG+GA vs. AA: OR= 0.36, 95%CI: 0.22∼0.58; Genotype GG vs. GA+AA: OR= 0.30, 95%CI: 0.09∼0.97; Genotype GA vs. AA: OR= 0.44, 95%CI: 0.27∼0.73), except the homozygous model. However, it was not found that SNP at the IL-10-1082G/A locus contributed to ALI or acute respiratory distress syndrome (ARDS). Moreover, the risk of ALI/RDS in Asia was associated with the IL-10-1082G/A locus in the allelic, recessive, and heterozygous models, while we did not observe this association across the Caucasian populations.

CONCLUSION

SNP at the IL-10-1082G/A locus contributed to the risk of ALI/RDS, allele G and genotype GG increasing the ALI/RDS risk, especially in Asia. Besides, allele G, genotype GG+GA, GG, and GA at the IL-10-1082G/A locus can increase susceptibility to NRDS.

Lung ultrasound (LUS) in pre-term neonates with respiratory distress: A prospective observational study

Aim

To find out the diagnostic use of lung ultrasound (LUS) in respiratory distress in neonates by taking clinico-radiological (clinical plus X-ray) diagnosis as the gold standard. Secondary objectives were to find out if modified LUS score can predict the need for surfactant therapy.

Methods

A prospective observational study was done in a tertiary care neonatal intensive care unit over a period of 1 year (January-December 2018). All pre-term infants with respiratory distress were screened with LUS and CXR within 2 h of admission and modified LUS score was calculated to find out the lung water content and its correlation with the severity of respiratory distress syndrome (RDS).

Results

In total, 92 neonates were screened during the study period, and 61 were finally diagnosed as RDS. The Kappa statistic between the clinico-radiological diagnosis and LUS diagnosis was 0.639. LUS diagnosis and CXR diagnosis had a Kappa correlation value of 0.786 (95% CI: 0.678-0.983). The most common LUS feature in RDS was pleural line thickening (100%), followed by whiteout lungs (75.4%). The modified LUS score was higher in babies who needed surfactant therapy (median (IQR): 49 (44, 53.5) vs. 29.5 (21, 46)) (P < 0.0001).

Conclusion

Our study shows that LUS in neonatal RDS can predict the severity of the disease, need for surfactant therapy and has good agreement with clinical and Xray diagnosis.

Efficacy, dose-response, and aerosol delivery of dry powder synthetic lung surfactant treatment in surfactant-deficient rabbits and premature lambs

BACKGROUND

Dry powder (DP) synthetic lung surfactant may be an effective means of noninvasive delivery of surfactant therapy to premature infants supported with nasal continuous positive airway pressure (nCPAP) in low-resource settings.

METHODS

Four experimental DP surfactant formulations consisting of 70% of phospholipids (DPPC:POPG 7:3), 3% Super Mini-B (SMB) or its sulfur-free derivate B-YL as SP-B peptide mimic, 25% of lactose or trehalose as excipient, and 2% of NaCl were formulated using spray drying. In vitro surface activity was confirmed with captive bubble surfactometry. Surfactant particle size was determined with a cascade impactor and inhaled dose was quantified using a spontaneously breathing premature lamb lung model supported with CPAP. In vivo surfactant efficacy was demonstrated in three studies. First, oxygenation and lung compliance were monitored after intratracheal instillation of resuspended DP surfactant in intubated, ventilated, lavaged, surfactant-deficient juvenile rabbits. In dose-response studies, ventilated, lavaged, surfactant-deficient rabbits received 30, 60, 120 or 240 mg/kg of DP B-YL:Lactose or B-YL:Trehalose surfactant by aerosol delivery with a low flow aerosol chamber via their endotracheal tube. Noninvasive aerosolization of DP B-YL:Trehalose surfactant via nasal prongs was tested in spontaneous breathing premature lambs supported with nCPAP. Intratracheal administration of 200 mg/kg of Curosurf®, a liquid porcine surfactant, was used as a positive control.

RESULTS

Mass median aerosol diameter was 3.6 μm with a geometric standard deviation of 1.8. All four experimental surfactants demonstrated high surface efficacy of intratracheal instillation of a bolus of ~ 100 mg/kg of surfactant with improvement of oxygenation and lung compliance. In the dose-response studies, rabbits received incremental doses of DP B-YL:Lactose or B-YL:Trehalose surfactant intratracheally and showed an optimal response in oxygenation and lung function at a dose of 120-240 mg/kg. Aerosol delivery via nasal prongs of 1 or 2 doses of ~ 100 mg/kg of B-YL:Trehalose surfactant to premature lambs supported with nCPAP resulted in stabilization of spontaneous breathing and oxygenation and lung volumes comparable to the positive control.

CONCLUSION

These studies confirm the clinical potential of DP synthetic lung surfactant with B-YL peptide as a SP-B mimic to alleviate surfactant deficiency when delivered as a liquid bolus or as an aerosol.

Is there a benefit of antenatal corticosteroid when given < 48 h before delivery?

OBJECTIVE

We assessed the association between a short antenatal corticosteroid administration-to-birth interval and neonatal outcome.

STUDY DESIGN

A retrospective study was conducted between 2010 and 2020. Eligible cases were singleton preterm live-born neonates born between 24-0/7 and 33-6/7 weeks of gestation and were initiated an ACS course of betamethasone. We divided the first 48 h following the first ACS administration to four time intervals and compared each time interval to those born more than 48 h following ACS administration. The primary outcome was a composite of adverse neonatal outcome, including neonatal mortality or any major neonatal morbidity.

RESULTS

A total of 200 women gave birth less than 48 h from receiving the first betamethasone injection, and 172 women gave birth within 2-7 days (48-168 h) from ACS administration. Composite adverse neonatal outcome was higher for neonates born less than 12 h from initial ACS administration compared to neonates born 2-7 days from the first betamethasone injection (55.45% vs. 29.07%, OR 3.45 95% CI [2.02-5.89], p value < 0.0001). However, there was no difference in composite adverse neonatal outcomes between neonates born 12-48 h following ACS administration and those born after 2-7 days. That was also true after adjusting for confounders.

CONCLUSIONS

12-24 h following ACS administration may be sufficient in reducing the same risk of neonatal morbidities as > 48 h following ACS administration. It may raise the question regarding the utility of the second dose of ACS.

Using pulmonary artery acceleration time to evaluate pulmonary hemodynamic changes on preterm infants with respiratory distress syndrome

BACKGROUND

Pulmonary artery acceleration time (PAAT) is a reliable and non-invasive method for assessing pulmonary hemodynamics. To date, few studies have used PAAT to assess preterm infants, especially those with respiratory distress syndrome (RDS). This study aimed to assess changes in PAAT among preterm infants with RDS undergoing pulmonary surfactant (PS) therapy or not, and determine its potential effects on the pulmonary vascular disease (PVD) outcomes of preterm infants with RDS in the late postnatal period.

METHODS

The risk of RDS was reviewed in 62 preterm infants with a gestational age of 26-31 weeks. The infants receiving PS therapy were allocated to the PS group, and the others were allocated to the control group. PAAT, right ventricular ejection time (RVET), and other ultrasonic parameters at 3 different time points after birth were studied and compared.

RESULTS

Infants in the PS group had a significantly lower PAAT (52.7±5.9 vs. 59.6±8.7; P=0.001) and PAAT/RVET (0.30±0.03 vs. 0.33±0.03; P=0.001) than those in the control group at 36 weeks postmenstrual age (PMA). No significant increases in PAAT/RVET were detected at 3 different times for the PS group (P=0.117), but both PAAT and PAAT/RVET increased significantly with time after birth in the control group (P<0.001).

CONCLUSIONS

Preterm infants with RDS might still have PVD in the late postnatal period and thus require long-term follow-up observation. PAAT appears to be a reliable non-invasive screening measure for evaluating pulmonary hemodynamics in preterm infants with RDS and late PVD.

Do maternal demographics and prenatal history impact the efficacy of betamethasone therapy for threatened preterm labor?

BACKGROUND

Betamethasone (BMZ) is used to accelerate fetal lung maturation in women with threatened preterm birth, but its efficacy is variable and limited by the lack of patient individualization in its dosing and administration. To determine sources of variability and potential opportunities for individualization of therapy, the objective of this study was to evaluate maternal factors associated with development of neonatal respiratory distress syndrome (RDS) in a cohort of women who received betamethasone.

METHODS

This study prospectively enrolled women, gestational ages 23-34 weeks, who received betamethasone for threatened preterm birth. Maternal demographics, prenatal history, and neonatal outcomes were abstracted from hospital records. RDS was the primary outcome. Associations between RDS diagnosis and maternal demographics, prenatal history, and betamethasone dosing were evaluated in a case-control analysis and multivariable regression adjusted for gestational age at delivery. Secondary analyses limited the cohort to women who delivered within 1 or 2 weeks of betamethasone dosing.

RESULTS

Of 209 deliveries, 90 (43 %) resulted in neonatal RDS. Within the overall cohort and controlling for gestational age at birth, RDS was only associated with cesarean births compared to vaginal births (adjusted OR 1.17 [1.06-1.29]). Route of delivery was also the only significant factor related to RDS in the 83 neonates delivered within 7 days of BMZ dosing. However, among 101 deliveries within 14 days of betamethasone dosing and controlling for gestational age at birth, women who experienced preterm premature rupture of membranes (PPROM) had lower RDS rates than those without PPROM (57.9 % vs. 80.2 %, adjusted OR 0.81 [0.67-0.99]). Maternal age, BMI, race, and ethnicity were not associated with RDS in the regression models.

CONCLUSIONS

Of maternal characteristics analyzed, only delivery by cesarean was associated with neonatal RDS after antenatal betamethasone use.

Bronchopulmonary dysplasia: a predictive scoring system for very low birth weight infants. A diagnostic accuracy study with prospective data collection

Our aim was to develop and validate a predictive risk score for bronchopulmonary dysplasia (BPD), according to two clinically used definitions: 1. Need for supplementary oxygen during ≥ 28 cumulative days, BPD28, 2. Need for supplementary oxygen at 36 weeks postmenstrual age (PMA), BPD36. Logistic regression was performed in a national cohort (infants born in Switzerland with a birth weight < 1501 g and/or between 23 0/7 and 31 6/7 weeks PMA in 2009 and 2010), to identify predictors of BPD. We built the score as the sum of predicting factors, weighted according to their ORs, and analysed its discriminative properties by calculating the area under the ROC (receiver operating characteristic) curves (AUCs). This score was then applied to the Swiss national cohort from the years 2014-2015 to perform external validation. The incidence of BPD28 was 21.6% in the derivation cohort (n = 1488) and 25.2% in the validation cohort (n = 2006). The corresponding numbers for BPD36 were 11.3% and 11.1%, respectively. We identified gestational age, birth weight, antenatal corticosteroids, surfactant administration, proven infection, patent ductus arteriosus and duration of mechanical ventilation as independent predictors of BPD28. The AUCs of the BPD risk scores in the derivation cohort were 0.90 and 0.89 for the BPD28 and BPD36 definitions, respectively. The corresponding AUCs in the validation cohort were 0.92 and 0.88, respectively.Conclusion: This score allows for predicting the risk of a very low birth weight infant to develop BPD early in life and may be a useful tool in clinical practice and neonatal research. What is Known: • Many studies have proposed scoring systems to predict bronchopulmonary dysplasia (BPD). • Such a risk prediction may be important to identify high-risk patients for counselling parents, research purposes and to identify candidates for specific treatment. What is New: • A predictive risk score for BPD was developed and validated in a large national multicentre cohort and its performance assessed by two indices of accuracy. • The developed scoring system allows to predict the risk of BPD development early but also at any day of life with high validity.

Introduction of less invasive surfactant administration (LISA), impact on diagnostic and therapeutic procedures in early life: a historical cohort study

Background

In preterm infants with Respiratory Distress Syndrome (RDS), Less Invasive Surfactant Administration (LISA) has been established to reduce the need of mechanical ventilation and might improve survival rates without bronchopulmonary dysplasia. The aim of this study was to investigate whether NICU care has changed after introduction of less invasive surfactant administration (LISA), with regard to diagnostic and therapeutic procedures in the first week of life.

Methods

Infants with gestational age < 32 weeks who received surfactant by LISA (June 2014 – December 2017, n = 169) were retrospectively compared to infants who received surfactant after intubation (January 2012 – May 2014, n = 155). Local protocols on indication for surfactant, early onset sepsis, blood transfusions and enteral feeding did not change between both study periods. Besides, as secondary outcome complications of prematurity were compared. Data was collected from electronic patient files and compared by univariate analysis through Students T-test, Mann Whitney-U test, Pearson Chi-Square test or Linear by Linear Association.

Results

All baseline characteristics of both groups were comparable. Compared to controls, LISA patients received a higher total surfactant dose (208 vs.160 mg/kg; p < 0.001), required redosing more frequently (32.5% vs. 21.3%; p = 0.023), but needed less mechanical ventilation (35.5% vs. 76.8%; p < 0.001). After LISA, infants underwent fewer X-rays (1.0 vs. 3.0, p < 0.001), blood gas examinations (3.0 vs. 5.0, p < 0.001), less inotropic drugs (9.5% vs. 18.1%; p = 0.024), blood transfusions (24.9% vs. 41.9%, p = 0.003) and had shorter duration of antibiotic therapy for suspected early onset sepsis (3.0 vs. 5.0 days, p < 0.001). Moreover, enteral feeding was advanced faster (120 vs. 100 mL/kg/d, p = 0.048) at day seven. There were no differences in complications of prematurity.

Conclusion

The introduction of LISA is associated with significantly fewer diagnostic and therapeutic procedures in the first week of life, which emphasizes the beneficial effects of LISA.

Respiratory Morbidity in Late-Preterm Births: A Prospective Observational Study at a Tertiary Care Hospital

OBJECTIVES

To study the neonatal respiratory morbidity in late-preterm neonates.

MATERIALS AND METHODS

This study was done over a period of 6 months (November 2014-April 2015) including 120 late-preterm births at a tertiary referral center.

RESULTS

Among the 120 late-preterm babies, 42 (35 %) developed respiratory morbidity. Respiratory distress syndrome (RDS) developed in 43 % of the babies who had not received steroid prophylaxis against 25.8 % receiving the same (p < 0.05). Among the indicated late-preterm deliveries, 45 % of babies developed respiratory morbidity in comparison with 22 % of the babies born following spontaneous onset of labor (p < 0.05). In the neonates with respiratory morbidity, male babies had a higher incidence than their female counterparts (48 vs. 24 % p < 0.05). Severity of RDS declined from 57 % for babies born at 34 weeks of gestation to 26.3 % for those born at 36 weeks (p 0.14). With each advancing week of gestation a significant reduction in the need for ventilator support (78 % at 34 weeks to 15 % at 36 weeks of gestation p < 0.05) was observed. Presence of antenatal risk factors did not significantly contribute to the respiratory morbidity.

CONCLUSION

The severity of respiratory morbidity and need for ventilator support declines with advancing gestational age; hence, every attempt must be made to prolong pregnancy till 36 weeks of gestation.