Invasive ventilation at the boundary of viability: A respiratory pathophysiology study of infants born between 22 and 24 weeks of gestation.

BACKGROUND: Invasive ventilation of infants born before 24 weeks of gestation is critical for survival and long-term respiratory outcomes, but currently there is a lack of evidence to guide respiratory management. We aimed to compare respiratory mechanics and gas exchange in ventilated extremely preterm infants born before and after 24 weeks of gestation. METHODS: Secondary analysis of two prospective observational cohort studies, comparing respiratory mechanics and indices of gas exchange in ventilated infants born at 22-24 weeks of gestation (N=14) compared to infants born at 25-27 weeks (N=37). The ventilation/perfusion ratio (VA/Q), intrapulmonary shunt, alveolar dead space (VDalv) and adjusted alveolar surface area (SA) were measured in infants born at the Neonatal Unit of King's College Hospital NHS Foundation Trust, London, UK. RESULTS: Compared to infants of 25-27 weeks, infants of 22-24 weeks had higher median (IQR) intrapulmonary shunt [18 (4 - 29) % vs 8 (2 - 12) %, p=0.044] and higher VDalv [0.9 (0.6 - 1.4) vs 0.6 (0.5 - 0.7) ml/kg, p=0.036], but did not differ in VA/Q. Compared to infants of 25-27 weeks, the infants of 22-24 weeks had a lower adjusted SA [509 (322- 687) vs 706 (564 - 800) cm2, p=0.044]. The infants in the two groups did not differ in any of the indices of respiratory mechanics. CONCLUSION: Ventilated infants born before 24 completed weeks of gestation exhibit abnormal gas exchange, with higher alveolar dead space and intrapulmonary shunt and a decreased alveolar surface area compared to extreme preterms born after 24 weeks of gestation.

Racial Differences in Respiratory Morbidity in Late Preterm Infants: A Retrospective Cohort Study.

Objectives. The role of race in late preterm respiratory morbidity has not been adequately described. We aimed to determine whether neonatal respiratory morbidity differs between Black and White late preterm infants. Methods. Single-centre retrospective cohort study at King's College Hospital NHS Foundation Trust, London, UK of infants born at 34 to <37 weeks of gestational age. The incidence of invasive ventilation was used as the main outcome. Results. In the study period 354 Black and 673 White late preterm infants were admitted. Black, compared to white infants, had a lower incidence of invasive ventilation (19% vs 27%, P < .001) and a lower incidence of non-invasive ventilation (22% vs 34%, P < .001). Black infants had a shorter duration and cost of stay compared to White infants (P = .011 and <0.001 respectively). Conclusion. Black late preterm infants needed less frequently invasive and non-invasive ventilation and had a shorter duration and cost of stay compared to White late preterm infants.

Chorioamnionitis and respiratory outcomes in prematurely born children: a systematic review and meta analysis.

INTRODUCTION: To conduct a systematic review and meta-analysis of the association between chorioamnionitis and respiratory outcomes of prematurely born children. CONTENT: Pubmed, Medline and Embase were searched for relevant studies. Studies were included if they assessed prematurely born children, who had been exposed to chorioamnionitis and had either lung function testing or assessment of wheeze or asthma following NICU discharge. Two reviewers independently screened the search results, applied inclusion criteria and assessed methodological quality. One reviewer extracted the data and these were checked by a second reviewer. SUMMARY: 1,237 studies were identified, but only eight which included 35,000 infants, fulfilled the inclusion criteria. One study looked at both lung function results and wheeze or asthma in childhood. Four of five studies found an association between wheeze/asthma in childhood and exposure to chorioamnionitis: the overall Odds Ratio (OR) for developing wheeze/asthma in childhood was OR 1.71 (95 % CI: 1.55-1.89). Four studies looked at lung function in childhood, three of which showed no statistically significant association between chorioamnionitis exposure and altered lung function. One study found lower lung function in those exposed to chorioamnionitis and lower expiratory flows with increasing levels of chorioamnionitis (forced expiratory flow at 50 % of exhaled forced vital capacity (=FEF50) p=0.012, forced expiratory flow at 25-75 % of the forced vital capacity is exhaled (=FEF25-75) p=0.014). OUTLOOK: There was a significant association between chorioamnionitis and the development of wheeze or asthma in childhood, but overall not in impairment of lung function.

Does Preterm Prolonged Rupture of Membranes Increase the Risk of Needing Invasive Respiratory Support? A Retrospective Single-Centre Study.

(1) Background: Preterm premature rupture of membranes (PPROM) has been associated with increased perinatal morbidity, but the effect of PPROM on respiratory disease has not been previously quantified. We hypothesised that PPROM would be associated with a higher incidence of invasive ventilation. (2) Methods: A retrospective cohort study at the Neonatal Unit at King's College Hospital NHS Foundation Trust, London, UK, was conducted on infants born before 37 weeks of gestation. PPROM was defined as the rupture of membranes for >48 h. (3) Results: We reviewed 1901 infants (434 with PPROM) with a median (IQR) gestational age of 32.4 (28.7-35.0) weeks. The median (IQR) duration of rupture of membranes in the infants with PPROM was 129 (78-293) h. The incidence of invasive ventilation was 56% in the infants with PPROM and 46% in the infants without PPROM (p < 0.001). Following regression analysis, PPROM was significantly related to a higher incidence of invasive ventilation (odds ratio: 1.48; 95% CI: 1.13-1.92, adjusted p = 0.004) after adjusting for birth weight [odds ratio = 0.34; 95% CI: 0.33-0.43, adjusted p < 0.001], Apgar score at 10 min [odds ratio =0.61; 95% CI: 0.56-0.66, adjusted p < 0.001] and antenatal corticosteroid use (adjusted p = 0.939). (4) Conclusions: PPROM was associated with a 1.48-fold higher risk of needing invasive ventilation.

Correlation of fetal lung area with MRI derived pulmonary volume.

BACKGROUND: Neonatal chest-Xray (CXR)s are commonly performed as a first line investigation for the evaluation of respiratory complications. Although lung area derived from CXRs correlates well with functional assessments of the neonatal lung, it is not currently utilised in clinical practice, partly due to the lack of reference ranges for CXR-derived lung area in healthy neonates. Advanced MR techniques now enable direct evaluation of both fetal pulmonary volume and area. This study therefore aims to generate reference ranges for pulmonary volume and area in uncomplicated pregnancies, evaluate the correlation between prenatal pulmonary volume and area, as well as to assess the agreement between antenatal MRI-derived and neonatal CXR-derived pulmonary area in a cohort of fetuses that delivered shortly after the antenatal MRI investigation. METHODS: Fetal MRI datasets were retrospectively analysed from uncomplicated term pregnancies and a preterm cohort that delivered within 72 h of the fetal MRI. All examinations included T2 weighted single-shot turbo spin echo images in multiple planes. In-house pipelines were applied to correct for fetal motion using deformable slice-to-volume reconstruction. An MRI-derived lung area was manually segmented from the average intensity projection (AIP) images generated. Postnatal lung area in the preterm cohort was measured from neonatal CXRs within 24 h of delivery. Pearson correlation coefficient was used to correlate MRI-derived lung volume and area. A two-way absolute agreement was performed between the MRI-derived AIP lung area and CXR-derived lung area. RESULTS: Datasets from 180 controls and 10 preterm fetuses were suitable for analysis. Mean gestational age at MRI was 28.6 ± 4.2 weeks for controls and 28.7 ± 2.7 weeks for preterm neonates. MRI-derived lung area correlated strongly with lung volumes (p < 0.001). MRI-derived lung area had good agreement with the neonatal CXR-derived lung area in the preterm cohort [both lungs = 0.982]. CONCLUSION: MRI-derived pulmonary area correlates well with absolute pulmonary volume and there is good correlation between MRI-derived pulmonary area and postnatal CXR-derived lung area when delivery occurs within a few days of the MRI examination. This may indicate that fetal MRI derived lung area may prove to be useful reference ranges for pulmonary areas derived from CXRs obtained in the perinatal period.

Chest radiographic thoracic areas and respiratory outcomes in infants with anterior abdominal wall defects.

OBJECTIVES: Infants with anterior abdominal wall defects (AWD) can suffer from pulmonary complications. Our aims were to determine if the chest radiographic thoracic areas (CRTAs) on day one differed between infants with exomphalos or gastroschisis, whether this related to differing severity of outcomes and if they were lower than those of controls indicating abnormal antenatal lung growth. METHODS: A review of infants with exomphalos or gastroschisis born between January 2004 and January 2023 was conducted. The control group was term, newborn infants ventilated for poor respiratory drive at birth. Chest radiographs on day one were analysed and the highest CRTA in the first 24 h after birth for each infant included in the analysis. RESULTS: The 127 infants with gastroschisis had a lower gestational age and birthweight than the 62 exomphalos infants and 130 controls (all p<0.001) The CRTAs of the controls were greater than the CRTAs of the exomphalos and the gastroschisis infants (p = 0.001). The median CRTA corrected for birthweight was lower in the exomphalos infants [688, IQR 568-875 mm2/kg] than the gastroschisis infants [813, IQE 695-915 mm2/kg] No gastroschisis infant developed bronchopulmonary dysplasia (BPD). A CRTA of 1759 mm2 had a sensitivity of 81 % and specificity of 71 % in predicting BPD in infants with exomphalos. CONCLUSIONS: Infants with gastroschisis or exomphalos had lower CRTAs than controls suggesting both groups had abnormal antenatal lung development. The CRTA was lower in the exomphalos infants who also had worse respiratory outcomes, hence CRTA assessment may a useful prognostic aid.

Maternal and infant outcomes in women with sickle cell disease: a matched cohort study.

OBJECTIVE: Women with sickle cell disease (SCD) have adverse maternal and infant outcomes. Our aim was to determine whether the outcomes of SCD mothers and their infants differed from African or Caribbean women not affected by SCD and whether there were differences between SCD individuals with the haemoglobin SS (HbSS) or haemoglobin SC (HbSC) genotypes. Furthermore, we wished to determine if any differences related to deprivation. DESIGN: A matched cohort study. SETTING: Tertiary perinatal centre in London PATIENTS: 4964 African or Caribbean women without SCD and 148 with SCD. MAIN OUTCOME MEASURES: Mode of delivery, maternal exchange transfusion, birthweight, neonatal unit admission, neonatal death and deprivation indices RESULTS: SCD women were more likely to be delivered by caesarean section (p<0.001) and had babies of lower birthweight (p<0.001). Their infants were no more likely to be admitted to neonatal intensive care unit or suffer a neonatal death. There were no significant differences between the SCD women and those without SCD in their deprivation index or deprivation decile. The women with the HbSS genotype compared to those with the HbSC genotype were more anaemic (p<0.02), required more exchange transfusions (p<0.001) and were more likely to be delivered by caesarean section (p=0.008). The infant outcomes did not differ significantly between the genotypes. CONCLUSIONS: Although, the SCD women, particularly those with the HbSS genotype, had greater morbidity, infant morbidity, and mortality was similar in mothers with the HbSS or HbSC genotypes and those without SCD.

Capnography waveforms: basic interpretation in neonatal intensive care.

End-tidal capnography can provide useful clinical information displayed on the ventilator screen or bedside monitor. It is important that clinicians can assess and utilise this information to assist in identifying underlying complications and pulmonary pathology. Sudden change or loss of the CO2 waveform can act as a safety measure in alerting clinicians of a dislodged or blocked endotracheal tube, considering the concurrent flow and volume waveforms. Visual pattern recognition by the clinicians of commonly seen waveform traces may act as an adjunct to other modes of ventilatory monitoring techniques. Waveforms traces can aid clinical management, help identify cases of ventilation asynchrony between the infant and the ventilator. We present some common clinical scenarios where tidal capnography can be useful in the timely identification of pulmonary complication and for practical troubleshooting at the cot-side.