The Diaphragmatic Initiated Ventilatory Assist (DIVA) trial: study protocol for a randomized controlled trial comparing rates of extubation failure in extremely premature infants undergoing extubation to non-invasive neurally adjusted ventilatory assist versus non-synchronized nasal intermittent positive pressure ventilation.

BACKGROUND: Invasive mechanical ventilation contributes to bronchopulmonary dysplasia (BPD), the most common complication of prematurity and the leading respiratory cause of childhood morbidity. Non-invasive ventilation (NIV) may limit invasive ventilation exposure and can be either synchronized or non-synchronized (NS). Pooled data suggest synchronized forms may be superior. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) delivers NIV synchronized to the neural signal for breathing, which is detected with a specialized catheter. The DIVA (Diaphragmatic Initiated Ventilatory Assist) trial aims to determine in infants born 240/7-276/7 weeks' gestation undergoing extubation whether NIV-NAVA compared to non-synchronized nasal intermittent positive pressure ventilation (NS-NIPPV) reduces the incidence of extubation failure within 5 days of extubation. METHODS: This is a prospective, unblinded, pragmatic, multicenter phase III randomized clinical trial. Inclusion criteria are preterm infants 24-276/7 weeks gestational age who were intubated within the first 7 days of life for at least 12 h and are undergoing extubation in the first 28 postnatal days. All sites will enter an initial run-in phase, where all infants are allocated to NIV-NAVA, and an independent technical committee assesses site performance. Subsequently, all enrolled infants are randomized to NIV-NAVA or NS-NIPPV at extubation. The primary outcome is extubation failure within 5 days of extubation, defined as any of the following: (1) rise in FiO2 at least 20% from pre-extubation for > 2 h, (2) pH ≤ 7.20 or pCO2 ≥ 70 mmHg; (3) > 1 apnea requiring positive pressure ventilation (PPV) or ≥ 6 apneas requiring stimulation within 6 h; (4) emergent intubation for cardiovascular instability or surgery. Our sample size of 478 provides 90% power to detect a 15% absolute reduction in the primary outcome. Enrolled infants will be followed for safety and secondary outcomes through 36 weeks' postmenstrual age, discharge, death, or transfer. DISCUSSION: The DIVA trial is the first large multicenter trial designed to assess the impact of NIV-NAVA on relevant clinical outcomes for preterm infants. The DIVA trial design incorporates input from clinical NAVA experts and includes innovative features, such as a run-in phase, to ensure consistent technical performance across sites. TRIAL REGISTRATION: www. CLINICALTRIALS: gov , trial identifier NCT05446272 , registered July 6, 2022.

Carnitine-Acylcarnitine Translocase Deficiency Masked by Extreme Prematurity.

Carnitine-acylcarnitine translocase (CACT) deficiency is a rare disorder of long chain fatty acid oxidation with a very high mortality rate due to cardiomyopathy or multiorgan failure. We present the course of a very premature infant with early onset CACT deficiency complicated by multiple episodes of necrotizing enterocolitis, sepsis, and liver insufficiency, followed by eventual demise. The complications of prematurity, potentiated by the overlay of CACT deficiency, contributed to the difficulty of reaching the ultimate diagnosis of CACT deficiency.

The Effect of Extended Continuous Positive Airway Pressure on Changes in Lung Volumes in Stable Premature Infants: A Randomized Controlled Trial.

OBJECTIVE: To compare changes in lung volumes, as measured by functional residual capacity (FRC), through to discharge in stable infants randomized to 2 weeks of extended continuous positive airway pressure CPAP (eCPAP) vs CPAP discontinuation (dCPAP). STUDY DESIGN: Infants born at ≤32 weeks of gestation requiring ≥24 hours of CPAP were randomized to 2 weeks of eCPAP vs dCPAP when meeting CPAP stability criteria. FRC was measured with the nitrogen washout technique. Infants were stratified by gestational age (<28 and ≥ 28 weeks) and twin gestation. A linear mixed-effects model was used to evaluate the change in FRC between the 2 groups. Data were analyzed blinded to treatment group allocation. RESULTS: Fifty infants were randomized with 6 excluded, for a total of 44 infants. Baseline characteristics were similar in the 2 groups. The infants randomized to eCPAP vs dCPAP had a greater increase in FRC from randomization through 2 weeks (12.6 mL vs 6.4 mL; adjusted 95% CI, 0.78-13.47; P = .03) and from randomization through discharge (27.2 mL vs 17.1 mL; adjusted 95% CI, 2.61-17.59; P = .01). CONCLUSIONS: Premature infants randomized to eCPAP had a significantly greater increase in FRC through discharge compared with those randomized to dCPAP. An increased change in FRC may lead to improved respiratory health. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02249143.

Insulin resistance of glycogen synthase mediated by o-linked N-acetylglucosamine.

We have investigated the mechanism by which high concentrations of glucose inhibit insulin stimulation of glycogen synthase. In NIH-3T3-L1 adipocytes cultured in low glucose (LG; 2.5 mm), the half-maximal activation concentration (A(0.5)) of glucose 6-phosphate was 162 +/- 15 microm. Exposure to either high glucose (HG; 20 mm) or glucosamine (GlcN; 10 mm) increased the A(0.5) to 558 +/- 61 or 612 +/- 34 microm. Insulin treatment with LG reduced the A(0.5) to 96 +/- 10 microm, but cells cultured with HG or GlcN were insulin-resistant (A(0.5) = 287 +/- 27 or 561 +/- 77 microm). Insulin resistance was not explained by increased phosphorylation of synthase. In fact, culture with GlcN decreased phosphorylation to 61% of the levels seen in cells cultured in LG. Hexosamine flux and subsequent enzymatic protein O-glycosylation have been postulated to mediate nutrient sensing and insulin resistance. Glycogen synthase is modified by O-linked N-acetylglucosamine, and the level of glycosylation increased in cells treated with HG or GlcN. Treatment of synthase in vitro with protein phosphatase 1 increased basal synthase activity from cells cultured in LG to 54% of total activity but was less effective with synthase from cells cultured in HG or GlcN, increasing basal activity to only 13 or 16%. After enzymatic removal of O-GlcNAc, however, subsequent digestion with phosphatase increased basal activity to over 73% for LG, HG, and GlcN. We conclude that O-GlcNAc modification of glycogen synthase results in the retention of the enzyme in a glucose 6-phosphate-dependent state and contributes to the reduced activation of the enzyme in insulin resistance.