Clinical usefulness of reintubation criteria in extremely preterm infants: a cohort study

OBJECTIVE

To describe the thresholds of instability used by clinicians at reintubation and evaluate the accuracy of different combinations of criteria in predicting reintubation decisions.

DESIGN

Secondary analysis using data obtained from the prospective observational Automated Prediction of Extubation Readiness study (NCT01909947) between 2013 and 2018.

SETTING

Multicentre (three neonatal intensive care units).

PATIENTS

Infants with birth weight ≤1250 g, mechanically ventilated and undergoing their first planned extubation were included.

INTERVENTIONS

After extubation, hourly O2 requirements, blood gas values and occurrence of cardiorespiratory events requiring intervention were recorded for 14 days or until reintubation, whichever came first.

MAIN OUTCOME MEASURES

Thresholds at reintubation were described and grouped into four categories: increased O2, respiratory acidosis, frequent cardiorespiratory events and severe cardiorespiratory events (requiring positive pressure ventilation). An automated algorithm was used to generate multiple combinations of criteria from the four categories and compute their accuracies in capturing reintubated infants (sensitivity) without including non-reintubated infants (specificity).

RESULTS

55 infants were reintubated (median gestational age 25.2 weeks (IQR 24.5-26.1 weeks), birth weight 750 g (IQR 640-880 g)), with highly variable thresholds at reintubation. After extubation, reintubated infants had significantly greater O2 needs, lower pH, higher pCO2 and more frequent and severe cardiorespiratory events compared with non-reintubated infants. After evaluating 123 374 combinations of reintubation criteria, Youden indices ranged from 0 to 0.46, suggesting low accuracy. This was primarily attributable to the poor agreement between clinicians on the number of cardiorespiratory events at which to reintubate.

CONCLUSIONS

Criteria used for reintubation in clinical practice are highly variable, with no combination accurately predicting the decision to reintubate.

Monogenic Causes in the Type 1 Diabetes Genetics Consortium Cohort: Low Genetic Risk for Autoimmunity in Case Selection

HYPOTHESIS

About 1% of patients clinically diagnosed as type 1 diabetes have non-autoimmune monogenic diabetes. The distinction has important therapeutic implications but, given the low prevalence and high cost of testing, selecting patients to test is important. We tested the hypothesis that low genetic risk for type 1 diabetes can substantially contribute to this selection.

METHODS

As proof of principle, we examined by exome sequencing families with 2 or more children, recruited by the Type 1 Diabetes Genetics Consortium (T1DGC) and selected for negativity for 2 autoantibodies and absence of risk human leukocyte antigen haplotypes.

RESULTS

We examined 46 families that met the criteria. Of the 17 with an affected parent, 7 (41.2%) had actionable monogenic variants. Of 29 families with no affected parent, 14 (48.3%) had such variants, including 5 with recessive pathogenic variants of WFS1 but no report of other features of Wolfram syndrome. Our approach diagnosed 55.8% of the estimated number of monogenic families in the entire T1DGC cohort, by sequencing only 11.1% of the autoantibody-negative ones.

CONCLUSIONS

Our findings justify proceeding to large-scale prospective screening studies using markers of autoimmunity, even in the absence of an affected parent. We also confirm that nonsyndromic WFS1 variants are common among cases of monogenic diabetes misdiagnosed as type 1 diabetes.

Five-year single center experience on surfactant treatment in preterm infants with respiratory distress syndrome: LISA vs INSURE

BACKGROUND

Surfactant administration traditionally involved endotracheal intubation and mechanical ventilation, which is associated with a risk of barotrauma and volutrauma.

OBJECTIVE

To compare the morbidity and mortality rates between LISA-treated and INSURE-treated premature babies with respiratory distress syndrome (RDS).

METHODS

We assessed retrospectively the medical records of preterm infants who were born at 25^0/7 to 29^6/7 weeks of gestation and were administered surfactant initially either with LISA or INSURE method over a five-year period.

RESULTS

Analysis of the data of 205 LISA-treated and 178 INSURE-treated infants revealed the mean gestational age as 28.1 ± 1.3 and 28 ± 1.3 weeks and mean birth weight as 1041 ± 205 and 1029 ± 222 g in LISA and INSURE groups, respectively. The mechanical ventilation requirement in the first 72 h of life (%26.8-%42.1, p = 0.002) and the incidence of moderate-severe BPD (%12.2-%21.9, p = 0.01) were lower in LISA-treated infants. LISA method was found as an independent factor in reducing mechanical ventilation requirement in the first 72 h of life and incidence of moderate-severe BPD [RR: -0.49 (%95 CI -0.28 to -0.85), p = 0.01].

CONCLUSION

Data obtained from our five-year clinical experience are comparable with the recent literature. LISA is currently the most suitable method of surfactant administration and it should be the first choice in spontaneously breathing infants considering its favorable effects on respiratory morbidities in preterm infants with RDS.

A complete, homozygous CRX deletion causing nullizygosity is a new genetic mechanism for Leber congenital amaurosis

CRX is a transcription factor required for activating the expression of many photoreceptor-neuron genes. CRX may be mutated in three forms of human blindness; Leber congenital amaurosis (LCA), cone-rod degeneration (CRD) and retinitis pigmentosa (RP). The pathogenic mechanism in most cases is likely dominant negative, with gain of function. We report a novel, complete homozygous CRX deletion in LCA. We identified a Lebanese family with 3 affected LCA cases. The proband was sequenced by NGS. Quantitative PCR, array comparative genomic hybridization, and long range PCR were performed. Full eye examinations, OCT and photography were performed. We identified a homozygous 56,000 bp deletion of CRX, which co-segregates and is heterozygous in four parents, who report normal vision. The blind children with LCA manifest severe retinal degeneration, a phenotype typical for CRX and LCA. We hypothesized that a single copy of CRX (haplo-insufficiency) in the causes mild abnormal foveal development, but not LCA. Two parents had significant inner and outer foveal and photoreceptor abnormalities. This is the first reported case of a homozygous, complete CRX deletion. Nullizygosity of CRX thus causes LCA while haplo-insufficiency of CRX causes abnormal foveal development, but not LCA. Our data suggest a new disease mechanism for CRX.

Abnormal Capillary Vasodynamics Contribute to Ictal Neurodegeneration in Epilepsy

Seizure-driven brain damage in epilepsy accumulates over time, especially in the hippocampus, which can lead to sclerosis, cognitive decline, and death. Excitotoxicity is the prevalent model to explain ictal neurodegeneration. Current labeling technologies cannot distinguish between excitotoxicity and hypoxia, however, because they share common molecular mechanisms. This leaves open the possibility that undetected ischemic hypoxia, due to ictal blood flow restriction, could contribute to neurodegeneration previously ascribed to excitotoxicity. We tested this possibility with Confocal Laser Endomicroscopy (CLE) and novel stereological analyses in several models of epileptic mice. We found a higher number and magnitude of NG2+ mural-cell mediated capillary constrictions in the hippocampus of epileptic mice than in that of normal mice, in addition to spatial coupling between capillary constrictions and oxidative stressed neurons and neurodegeneration. These results reveal a role for hypoxia driven by capillary blood flow restriction in ictal neurodegeneration.