High-frequency ventilation in preterm infants and neonates.

High-frequency ventilation (HFV) has been used as a respiratory support mode for neonates for over 30 years. HFV is characterized by delivering tidal volumes close to or less than the anatomical dead space. Both animal and clinical studies have shown that HFV can effectively restore lung function, and potentially limit ventilator-induced lung injury, which is considered an important risk factor for developing bronchopulmonary dysplasia (BPD). Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. We will present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. We also discuss the study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates. IMPACT: Knowledge of how HFV works, how it influences cardiorespiratory physiology, and how to apply it in daily clinical practice has proven to be essential for its optimal and safe use. Therefore, we present important aspects of gas exchange, lung-protective concepts, clinical use, and possible adverse effects of HFV. The use of HFV in daily clinical practice in lung recruitment, determination of the optimal continuous distending pressure and frequency, and typical side effects of HFV are discussed. We also present study results on the use of HFV in respiratory distress syndrome in preterm infants and respiratory failure in term neonates.

Association of response time and intermittent hypoxemia in extremely preterm infants.

AIM: To determine the relationship between medical staff's response time (RT) to oxygen saturation (SpO2 ) below 80% and the associated time from tactile intervention until SpO2 normalisation (CT). METHODS: Time-lapse video and continuous SpO2 were recorded for six consecutive 24 h periods. Regression analyses of RT and SpO2 in association with postmenstrual age (PMA), weight, infant sex and frequency of intermittent hypoxemia (IH). RESULTS: Five hundred and twelve hypoxemia episodes received tactile intervention in 20 extremely preterm infants (gestational age ≤28 weeks, birthweight <1500 g). Median RT was 20.5 s (IQR 16.63-25.50). RT increased with increased IH frequency (p = 0.023) independently of PMA and weight. SpO2 decreased by 3.7% with every 10 s RT (p = 0.039). Time until SpO2 normalisation was strongly associated with RT (ß = 0.58, p = 0.042). The association was amplified by lower PMA (p = 0.043). Female preterm infants experienced longer RT than males (p = 0.027). Because the total length of an IH is the sum of RT and CT, preterm infants with low PMA can reach a critical hypoxemia duration of >60 s, even with short RT. CONCLUSION: The RT is a critical factor that affects the overall time of IH treatments and the depth of desaturation. The consequences of a prolonged RT are worse for more immature preterm infants.

Signaling Cascade Involved in Rapid Stimulation of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) by Dexamethasone.

Impairment of mucociliary clearance with reduced airway fluid secretion leads to chronically inflamed airways. Cystic fibrosis transmembrane conductance regulator (CFTR) is crucially involved in airway fluid secretion and dexamethasone (dexa) has previously been shown to elevate CFTR activity in airway epithelial cells. However, the pathway by which dexa increases CFTR activity is largely unknown. We aimed to determine whether the increase of CFTR activity by dexa is achieved by non-genomic signaling and hypothesized that the phosphoinositide 3-kinase (PI3K) pathway is involved in CFTR stimulation. Primary rat airway epithelial cells and human bronchial submucosal gland-derived Calu-3 cells were analyzed in Ussing chambers and kinase activation was determined by Western blots. Results demonstrated a critical involvement of PI3K and protein kinase B (AKT) signaling in the dexa-induced increase of CFTR activity, while serum and glucocorticoid dependent kinase 1 (SGK1) activity was not essential. We further demonstrated a reduced neural precursor cell expressed, developmentally downregulated 4-like (NEDD4L) ubiquitin E3 ligase activity induced by dexa, possibly responsible for the elevated CFTR activity. Finally, increases of CFTR activity by dexa were demonstrated within 30 min accompanied by rapid activation of AKT. In conclusion, dexa induces a rapid stimulation of CFTR activity which depends on PI3K/AKT signaling in airway epithelial cells. Glucocorticoids might thus represent, in addition to their immunomodulatory actions, a therapeutic strategy to rapidly increase airway fluid secretion.

Students experience the effects of climate change on children's health in role play and develop strategies for medical work - an interactive seminar.

Background: This project report describes the development and evaluation of an interactive seminar on the topic "medical effects of climate change on children's health". Objectives: The learning objectives are learning the basics and the direct and indirect connections between climate change and children's health. Future scenarios for affected children, parents and doctors are developed interactively. Subsequently, communication strategies concerning climate change are discussed so that students identify and analyze possibilities to become active. Methodology: The seminar was offered as an obligatory seminar for a total of 128 third-year medical students with one appointment of 45 minutes per course group as part of the interdisciplinary seminar series "Environmental Medicine". A course group consisted of 14 to 18 students. The seminar for the 2020 summer semester was developed as part of the interdisciplinary field of environmental medicine with the special feature of an interactive role play. The role play intends to give the students the opportunity to put themselves in the situation of affected children, parents and doctors of the future in order to develop detailed solution strategies. From 2020 to 2021, the seminar took place as online self-study due to the lockdown requirements. Since winter semester 2021/22, the seminar was held as an attendance event for the first time, although the switch to an online presence seminar with obligatory attendance had to take place after four seminar dates due to renewed lockdown requirements, which also took place four times. The evaluated results here refer to a total of eight dates in the winter semester 2021/22 and were carried out using a specially developed questionnaire, which was filled out voluntarily and anonymously by the students immediately after the respective seminar date. An overall grade as well as the appropriateness of the time and content of lectures and role play were asked for. Free text answers were possible for each question. Results: A total of 83 questionnaires were evaluated, 54 of which were from the four seminars in attendance, 15 were from the four online presence seminars that took place as an online live stream. The evaluation of the seminar resulted in an average grade of 1.7 for the face-to-face seminars and 1.9 for the online seminars. Content-related comments in the free-text answers addressed the desire for concrete solution strategies, more time for discussions and a more in-depth study of the topic. Numerous positive responses described the seminar as "very exciting", "good food for thought", "interesting and important topic". Conclusion: There is a very high interest on the topic of "climate change & health" among students There is an obvious need to integrate the topic on a larger scale into medical education. Ideally, the focus on children's health should be an integral part of the pediatric curriculum.

Incidence of Intermittent Hypoxemia Increases during Clinical Care and Parental Touch in Extremely Preterm Infants.

OBJECTIVES: An increased frequency of intermittent hypoxemia (IH) is associated with a higher risk for poor developmental outcomes, disability, or death in extremely preterm infants. The objective of the prFesent study is to quantify the effect of hands-on medical and parental interventions on the incidence of IH in extremely preterm infants. METHODS: An observational design with intraindividual comparisons was used. Blood oxygen saturation levels (SpO2) and time-lapse video were recorded. Frequency, duration, and time to occurrence of IH (SpO2 <80% for ≥10 s) were compared between nursing and medical care (NMC), health care by parents, skin-to-skin contact (SSC), touch in incubator, physiotherapy, and rest. Each infant was observed for six consecutive 24-h periods. Inclusion criteria were as follows: gestational age ≤28 weeks, birth weight <1500 g, postnatal age 0-6 weeks, gavage feeding, no severe illnesses or invasive procedures, no mechanical ventilation. RESULTS: The highest proportion of time with IH occurred during NMC (2.49%) and incubator touch (1.32%), the lowest during SSC (0.74%) and health care by parents (0.67%). IH frequency per hour was highest during NMC (2.95, IQR 1.19-4.01) and lowest during SSC (0.88, IQR 0.37-2.32, p < 0.001). While an increase in IH during NMC was expected, the high incidence during incubator touch was surprising. Parental touch in the incubator is intended to be soothing, not stressful. CONCLUSIONS: Future studies need to clarify how preterm infants process touch, which attributes of touch are fundamental trigger mechanisms of IH, and which handling strategies are most effective in lowering the incidence of IH during hands-on medical care.