Respiratory physiology during NAVA ventilation in neonates born with a congenital diaphragmatic hernia: The "NAVA-diaph" pilot study.

BACKGROUND: Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that delivers synchronized ventilation, proportional to the electrical activity of the diaphragm (EAdi). Although it has been proposed in infants with a congenital diaphragmatic hernia (CDH), the diaphragmatic defect and the surgical repair could alter the physiology of the diaphragm. AIM: To evaluate, in a pilot study, the relationship between the respiratory drive (EAdi) and the respiratory effort in neonates with CDH during the postsurgical period under either NAVA ventilation or conventional ventilation (CV). METHODS: This prospective physiological study included eight neonates admitted to a neonatal intensive care unit with a diagnosis of CDH. EAdi, esophageal, gastric, and transdiaphragmatic pressure, as well as clinical parameters, were recorded during NAVA and CV (synchronized intermittent mandatory pressure ventilation) in the postsurgical period. RESULTS: EAdi was detectable and there was a correlation between the ΔEAdi (maximal - minimal values) and the transdiaphragmatic pressure (r = 0.26, 95% confidence interval [CI] [0.222; 0.299]). There was no significant difference in terms of clinical or physiological parameters during NAVA compared to CV, including work of breathing. CONCLUSION: Respiratory drive and effort were correlated in infants with CDH and therefore NAVA is a suitable proportional mode in this population. EAdi can also be used to monitor the diaphragm for individualized support.

Phenotypic and genetic spectrum of alveolar capillary dysplasia: a retrospective cohort study.

OBJECTIVE: Alveolar capillary dysplasia (ACD) is one of the causes of pulmonary hypertension. Its diagnosis is histological but new pathogenetic data have emerged. The aim of this study was to describe a French cohort of patients with ACD to improve the comprehension and the diagnosis of this pathology which is probably underdiagnosed. METHODS: A retrospective observational study was conducted in French hospitals. Patients born between 2005 and 2017, whose biological samples were sent to the French genetic reference centres, were included. Clinical, histological and genetic data were retrospectively collected. RESULTS: We presented a series of 21 patients. The mean of postmenstrual age at birth was 37.6 weeks. The first symptoms appeared on the median of 2.5 hours. Pulmonary hypertension was diagnosed in 20 patients out of 21. Two cases had prolonged survival (3.3 and 14 months). Histological analysis was done on lung tissue from autopsy (57.1% of cases) or from percutaneous biopsy (28.6%). FOXF1 was found abnormal in 15 patients (71.4%): 8 deletions and 7 point mutations. Two deletions were found by chromosomal microarray. CONCLUSION: This study is one of the largest clinically described series in literature. It seems crucial to integrate genetics early into diagnostic support. We propose a diagnostic algorithm for helping medical teams to improve diagnosis of this pathology.

Implementation and evaluation of a paediatric nurse-driven sedation protocol in a paediatric intensive care unit.

BACKGROUND: Optimal sedation and analgesia is a challenge in paediatric intensive care units (PICU) because of difficulties in scoring systems and specific metabolism inducing tolerance and withdrawal. Excessive sedation is associated with prolonged mechanical ventilation and hospitalisation. Adult and paediatric data suggest that goal-directed sedation algorithms reduce the duration of mechanical ventilation. We implemented a nurse-driven sedation protocol in a PICU and evaluated its impact. METHODS: We conducted a before and after protocol implementation study in a population of children aged 0-18 years who required mechanical ventilation for at least 24 h between January 2013 and March 2015. After the protocol implementation in January 2014, nurses managed analgesia and sedation following an algorithm that included the COMFORT behaviour scale (COMFORT-B). Duration of mechanical ventilation was the primary outcome; secondary outcomes were total doses and duration of medications, PICU length of stay, incidence of ventilator-associated pneumonia, and occurrence of withdrawal symptoms. Pre-post analysis followed with segmented regression analysis of interrupted time series was used to assess the effect of protocol. RESULTS: A total of 200 children were analysed, including 107 before implementation and 93 children after implementation of the protocol. After implementation of the protocol, the total number of COMFORT-B scores per day of mechanical ventilation significantly increased from 3.9 ± 2.5 times during the pre-implementation period to 6.6 ± 3.5 times during the post-implementation period (p < 10-3). Mean duration of mechanical ventilation tended to be lower in the post-implementation period (8.3 ± 7.3 vs 6.6 ± 5.6 days, p = 0.094), but changes in either the trend per trimester from pre-implementation to post-implementation (p = 0.933) or the immediate change after implementation (p = 0.923) were not significant with segmented regression analysis. No significant change between pre- and post-implementation was shown for total dose of sedatives, withdrawal symptoms, agitation episodes, or unplanned endotracheal extubations. CONCLUSIONS: These results were promising and suggested that implementation of a nurse-driven sedation protocol in a PICU was feasible. Evaluation of sedation and analgesia was better after the protocol implementation; duration of mechanical ventilation and occurrence of withdrawal symptoms tended to be reduced.

Low phosphatemia in extremely low birth weight neonates: A risk factor for hyperglycemia?

BACKGROUND & AIMS: Hyperglycemia occurs in more than half of the extremely low birth weight (ELBW) neonates during the first weeks of life, and is correlated with an increased risk of morbi-mortality. Hypophosphatemia is another frequent metabolic disorder in this population. Data from animal, adult studies and clinical observation suggest that hypophosphatemia could induce glucose intolerance. Our aim was to determine whether a low phosphatemia is associated with hyperglycemia in ELBW neonates. METHODS: This observational study included ELBW infants admitted in a tertiary neonatal care center (2010-2011). According to the center's policy, they received parenteral nutrition from birth and human milk from day 1. Phosphatemia and glycemia were measured routinely during parenteral nutrition. Hyperglycemia was defined by two consecutives values >8.3 mmol/L (150 mg/dL). Statistical analysis used a joint model combining a mixed-effects and a survival submodels to measure the association between phosphate and hyperglycemia. RESULTS: The study included 148 patients. Mean gestational (Standard Deviation) age was 27.3 (1.6) weeks; mean birth weight was 803 (124) grams; 57% presented hyperglycemia. The multivariate joint model showed that the hazard of hyperglycemia at a given time was multiplied by 3 for each 0.41 mmol/L decrease of phosphate level at this time (p = 0.002) and by 3.85 for the same decreased of phosphate the day before (p = 0.0015). CONCLUSION: To our knowledge, this is the first study suggesting that low phosphatemia can be associated with hyperglycemia in ELBW neonates. Further studies will have to demonstrate whether better control of phosphatemia could help in preventing hyperglycemia.