Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature.

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Myocardial strain in newborn infants with tracheomalacia due to vascular rings, a pilot study.

BACKGROUND: Vascular rings (VR) may cause severe tracheomalacia and upper airway obstruction (UAO). Increased pulmonary artery pressure and cardiac dysfunction have been described in patients with chronic UAO, but has not been investigated in infants with obstruction associated with VR. The aim of this study is to evaluate myocardial strain in infants with UAO due to VR. METHOD: Demographic characteristics, respiratory symptoms, percentage of tracheal obstruction measured and classified using Computer Tomography, and lung function testing (LFT) were collected. Left (LV) and right ventricle (RV) systolic functions were measured using speckle tracking echocardiography longitudinal strain analysis (LS). Pulmonary artery pressure was evaluated using maximal tricuspid regurgitation jet velocity (TR) and LV end-systolic eccentricity index (EI). RESULTS: Fifteen cases were included in the study, six had mild tracheal obstruction (<50%), nine moderate-severe obstruction (≥50%). LV LS and RV LS were significantly reduced in cases with moderate to severe airway obstruction cases compared to those with mild airway obstruction (LV LS -15.9 versus -19.9%; RV LS -15.7 versus -20.5%, p = .04 and p = .02, respectively). Respiratory symptoms were more pronounced in moderate-severe cases. No significant differences in TR, EI, and LFT were observed. CONCLUSIONS: In cases of VR with severe tracheomalacia RV and LV myocardial strain is reduced, suggesting secondary cardiac dysfunction.

Changes in Breathing Patterns after Surgery in Severe Laryngomalacia.

BACKGROUND: Most of the studies regarding the surgical treatment of severe laryngomalacia (LM) have been aimed at describing the efficacy of the treatment in terms of improvement of clinical symptoms or anatomical findings. There are no studies specifically aimed at analyzing the changes in breathing patterns following surgical treatment for severe LM. OBJECTIVE: To review the breathing pattern changes before and after corrective surgery in infants with severe LM. STUDY DESIGN: A series of retrospective cases at a tertiary referral children's hospital. METHODS: Retrospective chart review of 81 infants who underwent supra-glottoplasty (SGP) for severe laryngomalacia between 2011 and 2020 at Bambino Gesù Children's Hospital of Rome, Italy. Among the patients, 47 (58%) were male and 34 (42%) were female. Twenty-one patients (26%) had one or more comorbidities condition. The data collected included age, symptoms, a polysomnography/pulse oximetry study, growth rate, the findings from flexible endoscopy, pre- and post-supra-glottoplasty (SGP) pulmonary function tests (PFTs) and, when indicated, 24 h pH-metry. Breathing patterns were studied during restful, normal sleep, using an ultrasonic flow-meter (Exhalyzer, Viasys) which measured: Tidal Volume (Vt), Respiratory Rate (RR), time to peak expiratory flow/expiratory time ratio (tPTEF/Te, an index of the patency of the lower airways) and mean expiratory/mean inspiratory flow ratio (MEF/MIF, an index of the patency of the upper airways) evaluated before surgical procedure (T1) and 3-6 weeks after (T2). Pre- and post-operative mean data were calculated and comparisons made with a Student T-test. RESULTS: The surgical procedure was well tolerated by all infants and no intraoperative or post-operatory long-term complications were noted. In T1, breathing patterns were characterized by low tidal volume and high tPTEF/Te and MEF/MIF ratios, suggesting a severe reduction in the patency of the upper airways in all patients. After surgery (T2), all the previously mentioned variables significantly improved, reaching normal values for the child's age. CONCLUSIONS: Supra-glottoplasty, as already described in several studies, is a safe and efficient procedure to treat severe laryngomalacia during infancy. The improvement in breathing patterns after surgery was reliably confirmed by a lung function test in our study, which showed the diagnostic value of testing respiratory functionality in the laryngomalacia and comparing them to clinical and endoscopic data. Moreover, considering the results obtained, we also propose the use of this available, dependable test to verify its therapeutic effects (post-surgery) and to monitor future respiratory development in these infants. Moreover, we believe that further studies will provide detailed grading guidelines for gravity of the LM, based on these functional lung tests.

Severe herpes virus 6 interstitial pneumonia in an infant with three variants in genes predisposing to lung disease.

Infections due to human herpesvirus 6 (HHV-6) are frequent during early childhood. Usually, they have a favorable clinical course. Conversely, HHV-6 congenital infections occur in about 1% of neonates and may present with more severe clinical pictures. HHV-6 can be found in lung tissues and bronchoalveolar lavage (BAL) samples from patients with pneumonia and in immunocompromised patients can cause mild to severe pneumonia. In neonates, the role of HHV-6 in the genesis of severe pneumonia is poorly defined still now. We describe a healthy infant with a late-onset (15 days of life) severe interstitial pneumonia and heavy HHV-6 genome load, persistently detected in its BAL fluid. The baby underwent high-frequency oscillatory ventilation, hydroxychloroquine, steroids, and ganciclovir for 6 weeks and at 9 months she died. Next-generation sequencing of genes known to cause neonatal respiratory insufficiency revealed the presence of a "probably pathogenetic" heterozygous variant in the autosomal recessive DRC1 gene, a heterozygous variant of unknown significance (VUS) in the autosomal recessive RSPH9 gene, and a heterozygous VUS in the autosomal recessive MUC5B gene. HHV-6 infection should be considered in the differential diagnosis of late-onset severe respiratory distress in neonates and the co-occurrence of genetic predisposing factors or modifiers should be tested by specific molecular techniques. The intensity of HHV-6 genome load in BAL fluid could be an indicator of the response to antiviral therapy.

Functional residual capacity and lung clearance index in infants treated for esophageal atresia and tracheoesophageal fistula.

BACKGROUND: Newborn babies with esophageal atresia/tracheoesophageal fistula (EA/TEF) are prone to respiratory tract disorders. Functional residual capacity (FRC) and lung clearance index (LCI) are commonly considered useful and sensitive tools to investigate lung function and early detecting airways diseases. The aim of the present study is to report the first series of EA/TEF infants prospectively evaluated for FRC and LCI. METHODS: Prospective observational cohort study of all patients treated for EA/TEF. Lung volume and ventilation inhomogeneity were measured by helium gas dilution technique using an ultrasonic flow meter. Babies were studied both in assisted controlled ventilation (sedated) and in spontaneous breathing (quiet sleep). Three consecutive FRC and LCI measurements were collected for each test at three different time points: before surgery (T0), 24hours after surgery (T1) and after extubation (T2). RESULTS: 16 EA newborns were eligible for the study between December 2011 and July 2013. Three were excluded because of technical problems. At T0 FRC values were in the normal range regardless the presence of TEF but worsened afterwards at T1, with a subsequent recovering after extubation; a significant improvement after surgery was observed concerning LCI while no differences were found in tidal volume. CONCLUSION: Helium gas dilution technique is a suitable method to measure the effect of surgery on lung physiology, even in ventilated infants with EA. The changes observed could be related to the ventilatory management and lung compression during surgical procedure.

Functional residual capacity (FRC) and lung clearance index (LCI) in mechanically ventilated infants: application in the newborn with congenital diaphragmatic hernia (CDH).

INTRODUCTION: Functional residual capacity (FRC) and lung clearance index (LCI) are sensitive parameters for early detection of airway disease in infancy. The closed helium dilution method has been applied to assess lung volume and ventilation inhomogeneity (VI) in spontaneously breathing infants. AIMS: The aims of this study were as follows: (1) to assess applicability of the helium gas dilution technique in mechanically ventilated infants with high-risk congenital diaphragmatic hernia (CDH) and to evaluate changes in breathing patterns, lung volume, and VI during the first days of life before and after surgery, and (2) to analyze the possible correlation between changes in lung volume, cerebral hemodynamics, and oxygenation before and after surgical correction of CDH through near-infrared spectroscopy (NIRS) monitoring. METHODS: Lung function tests were performed by multibreath washout traces with an ultrasonic flowmeter and helium gas dilution technique. For all babies, three acceptable FRC and LCI measurements were collected for each test (mean and SD of three measurements were calculated) before surgery (T0), 24 h after surgery (T1) during mechanical ventilation, and within 24 h after extubation in spontaneous breathing (T2). Cerebral and splanchnic hemodynamics were continuously monitored by NIRS during mechanical ventilation to evaluate relationships between changes in lung volume and capillary-venous oxyhemoglobin saturation in tissues. Fraction of inspired oxygen delivered was adjusted to keep oxygen saturation between 90% and 95%. RESULTS: Thirteen CDH infants were studied; median GA = 38 weeks (range 35-41) and median BW = 3000 g (range 1850-3670). FRC and LCI significantly improved after extubation when compared with pre-surgical values. No differences were found in tidal volume (Vt) and NIRS monitoring before and after surgery and after extubation. Neither LCI nor FRC was correlated with NIRS values. CONCLUSIONS: Helium gas dilution technique is an applicable and reliable technique to measure lung volumes and ventilation inhomogeneity also in ventilated infants. NIRS is a non-invasive technique to monitor tissue oxygenation during surgery and mechanical ventilation. In CDH newborns these preliminary data show an improvement in both FRC and LCI after extubation.