Effects of ventilation modalities on near-infrared spectroscopy in surgically corrected CDH infants

BACKGROUND

Near-infrared spectroscopy (NIRS) is a noninvasive technique for monitoring tissue oxygenation and perfusion. The aim of this study was to evaluate cerebral and splanchnic NIRS changes in CDH operated infants enrolled into the VICI trial and therefore randomized for ventilatory modalities.

MATERIALS AND METHODS

CDH newborns enrolled into the VICI trial (Netherlands Trial Register, NTR 1310) were randomized at birth for high-frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CMV) according to the trial. Cerebral oxygenation (rSO2C) and splanchnic oxygenation (rSO2S) were obtained by NIRS (INVOS 5100; Somanetics, Troy, MI) before and after surgery. Variations in rSO2C and rSO2S were evaluated. Mann-Whitney test and one-way ANOVA were used as appropriate. p<0.05 was considered significant.

RESULTS

Thirteen VICI trial patients underwent surgical repair between March 2011 and December 2012, and were enrolled in the study. Seven patients were assigned to HFOV and six to CMV group respectively. During surgery, a significant reduction in rSO2C (p=0.0001) and rSO2S (p=0.005) were observed. HFOV patients experienced prolonged reduction in rSO2C value (p=0.003) while rSO2S did not vary between HFOV and CMV (p=0.94).

CONCLUSIONS

Surgical CDH repair was associated with decrease of cerebral and splanchnic oxygenation, regardless of ventilation. Patients ventilated by HFOV need a longer time interval to recovery normal rSO2C values, than those ventilated by CMV. This may be owing to a different impact of HFOV on patients' hemodynamic status with a higher impairment on total venous return and its negative consequences on cardiac output.

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.

Growth and morbidity in infants with Congenital Diaphragmatic Hernia according to initial lung volume: A pilot study

Background In congenital diaphragmatic hernia (CDH) survivors, failure to thrive is a well-known complication, ascribed to several factors. The impact of lung volume on growth of CDH survivors is poorly explored. Our aim was to evaluate if, in CDH survivors, lung volume (LV) after extubation correlates with growth at 12 and 24 months of life. Methods LV (measured as functional residual capacity-FRC) was evaluated by multibreath washout traces with an ultrasonic flowmeter and helium gas dilution technique, shortly after extubation. All CDH survivors are enrolled in a dedicated follow-up program. For the purpose of this study, we analyzed the correlation between FRC obtained shortly after extubation and anthropometric measurements at 12 and 24 months of age. We also compared growth between infants with normal lungs and those with hypoplasic lungs according to FRC values. A p < 0.05 was considered as statistically significant. Results We included in the study 22 CDH survivors who had FRC analyzed after extubation and auxological follow-up at 12 and 24 months of age. We found a significant correlation between FRC and weight Z-score at 12 months, weight Z-score at 24 months and height Z-score at 24 months. We also demonstrated that CDH infants with hypoplasic lungs had a significantly lower weight at 12 months and at 24 months and a significantly lower height at 24 months, when compared to infants with normal lungs. Conclusion We analyzed the predictive value of bedside measured lung volumes in a homogeneous cohort of CDH infants and demonstrated a significant correlation between FRC and growth at 12 and 24 months of age. An earlier identification of patients that will require an aggressive nutritional support (such as those with pulmonary hypoplasia) may help reducing the burden of failure to thrive.

The Role of Lung Function Testing in Newborn Infants With Congenital Thoracic Arterial Anomalies

Introduction: Congenital thoracic arterial anomalies (CTAAs), such as complete or incomplete vascular rings, pulmonary artery sling, and innominate artery compression syndrome, may cause severe tracheomalacia and upper airway obstruction. An obstructive ventilatory pattern at lung function testing (LFT) has been suggested in the presence of CTAA. The severity of obstruction may be evaluated by LFT. Little is known about the use of LFT in newborn infants with CTAA. The aim of our study is to evaluate the role of LFT in CTAA diagnosis. Methods: This is a retrospective study, conducted between February 2016 and July 2020. All CTAA cases for whom LFT was performed preoperatively were considered for inclusion. Tidal volume (Vt), respiratory rate, and the ratio of time to reach the peak tidal expiratory flow over total expiratory time (tPTEF/tE) were assessed and compared to existing normative data. Demographics and CTAA characteristics were also collected. Results: Thirty cases were included. All infants with CTAA showed a significantly reduced Vt and tPTEF/tE, compared to existing normative data suggesting an obstructive pattern. No significant differences were found for LFT between cases with a tracheal obstruction <50% compared to those with tracheal obstruction ≥50%, or between cases with and without symptoms. Sixteen infants (53.3%) had respiratory symptoms related to CTAA. Of these, only two cases had also dysphagia. Conclusion: LFT values were significantly reduced in cases with CTAA before surgery. LFT represents a potential feasible and non-invasive useful tool to guide diagnosis in the suspect of CTAA.

Use of levosimendan in hemodynamic management of heart failure in two neonates with intracranial arteriovenous shunts: a case series

BACKGROUND

The hemodynamic status of newborns with intracranial arteriovenous shunts (AVSs) may be extremely complex. Mini-invasive hemodynamic monitoring through innovative techniques such as Near-Infrared Spectroscopy (NIRS) and Pressure Recording Analytical Method (PRAM) may help in understanding hemodynamics in newborns with AVSs. Levosimendan is a calcium sensitizer and inodilator, and it is known to improve ventricular function, but its use in newborns is limited. In our cases, we evaluated the effect of levosimendan on hemodynamics through NIRS and PRAM.

CASE PRESENTATION

Herein, we report the cases of two neonates with intracranial arteriovenous shunts, in whom we used levosimendan to manage cardiac failure refractory to conventional treatment. Levosimendan was used at a dosage of 0.1 mcg/kg/min for 72 h. Combined use of NIRS and PRAM helped in real-time monitoring of hemodynamic effects; in particular, levosimendan determined significant improvement in myocardium contractility as well as a reduction of heart rate.

CONCLUSION

In two neonatal cases of AVSs, levosimendan led to an overall hemodynamic stabilization, documented by the combination of NIRS and PRAM. Our results suggest introducing levosimendan as a second-line treatment in cases of severe cardiac dysfunction due to AVSs without improvement using standard treatment strategies. Future prospective and larger studies are highly warranted.

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.

Post-operative ventilation strategies after surgical repair in neonates with esophageal atresia: A retrospective cohort study

BACKGROUND

Infants affected by Esophageal atresia (EA) with or without tracheoesophageal fistula (TEF) may require non-invasive ventilation (NIV) in the post-operative period after elective extubation, especially if born preterm. The aim of the paper is to evaluate the role of different ventilation strategies on anastomotic complications, specifically on anastomotic leak (AL).

MATERIALS AND METHODS

Retrospective single Institution study, including all consecutive neonates affected by EA with or without TEF in a 5-year period study (from 2014 to 2018). Only infants with a primary anastomosis were included in the study. All infants were mechanically ventilated after surgery and electively extubated after 6-7 days. The duration of invasive ventilation was decided on a case-by-case basis after surgery, based on the pre-operative esophageal gap and intraoperative findings. The need for non-invasive ventilation (NCPAP, NIPPV, and HHHFNC) after extubation and extubation failure with the need for mechanical ventilation in the post-operative period were assessed. The primary outcome evaluated was the rate of anastomotic leak.

RESULTS

102 EA/TEF infants were managed in the study period. Sixty-seven underwent primary anastomosis. Of these, 29 (43.3%) were born preterm. Patients who required ventilation (n = 32) had a significantly lower gestational age as well as birthweight (respectively p = 0.007 and p = 0.041). 4/67 patients had an AL after surgical repair, with no statistical differences among post-operative ventilation strategies.

CONCLUSION

We found no significant differences in the rate of anastomotic leak (AL) according to post-operative ventilation strategies in neonates operated on for EA/TEF.

Use of N-Acetylcysteine in Preterm Neonates with Enteral Feeding Intolerance and Intestinal Obstruction: A Case Series and Review of the Literature

(1) Background: The use of N-acetylcysteine (NAC) to relieve meconium obstruction of prematurity in the first days of life has been reported, with NAC reducing the viscosity of luminal contents by cleaving the disulfide bonds of mucoproteins. However, its use in this population should be further explored since it has been associated with hypernatremia and transient increase in transaminases and bilirubin. (2) Methods: In this retrospective study, we included neonates admitted because of enteral feeding intolerance and intestinal obstruction from 2019 to 2021 who received NAC as a rescue therapy before explorative laparotomy. (3) Results: We summarized the clinical presentation of six preterm neonates with enteral feeding intolerance and intestinal obstruction who received NAC as a rescue therapy. Four infants (66.7%) gradually improved without the need for explorative laparotomy, whereas two infants (33.3%) underwent the creation of an ileostomy. No cases of hypernatremia or hepatic derangement associated with NAC therapy were observed. (4) Conclusions: We described the use of NAC treatment by nasogastric tube and/or rectal enemas in preterm infants with enteral feeding intolerance and intestinal obstruction after a multidisciplinary assessment, but the limited sample size did not allow us to obtain definitive conclusions and further research is needed in this field, given the limited evidence about NAC treatment in preterm infants.