High-Frequency Positive Pressure Ventilation as Primary Rescue Strategy for Patients with Congenital Diaphragmatic Hernia: A Comparison to High-Frequency Oscillatory Ventilation

Objective The aim of this article was to evaluate high-frequency positive pressure ventilation (HFPPV) compared with high-frequency oscillatory ventilation (HFOV) as a rescue ventilation strategy for patients with congenital diaphragmatic hernia (CDH). HFPPV is a pressure-controlled conventional ventilation method utilizing high respiratory rate and low positive end-expiratory pressure. Study Design Seventy-seven patients diagnosed with CDH from January 2005 to September 2019 who were treated with stepwise progression from HFPPV to HFOV versus only HFOV were included. Fisher's exact test and the Kruskal–Wallis test were used to compare outcomes. Results Patients treated with HFPPV + HFOV had higher survival to discharge (80 vs. 50%, p = 0.007) and to surgical intervention (95.6 vs. 68.8%, p = 0.003), with average age at repair 2 days earlier (p = 0.004). Need for extracorporeal membrane oxygenation (p = 0.490), inhaled nitric oxide (p = 0.585), supplemental oxygen (p = 0.341), and pulmonary hypertension medications (p = 0.381) were similar. Conclusion In CDH patients who fail respiratory support with conventional ventilation, HFPPV may be used as an intermediary mode of rescue ventilation prior to HFOV without adverse effects. Key Points

Assessment of Respiratory System Resistance during High-Frequency Oscillatory Ventilation Based on In Vitro Experiment

High-frequency oscillatory ventilation (HFOV) is a type of mechanical ventilation with a protective potential characterized by a small tidal volume. Unfortunately, HFOV has limited monitoring of ventilation parameters and mechanical parameters of the respiratory system, which makes it difficult to adjust the continuous distension pressure (CDP) according to the individual patient’s airway status. Airway resistance Raw is one of the important parameters describing the mechanics of the respiratory system. The aim of the presented study was to verify in vitro whether the resistance of the respiratory system Rrs can be reliably determined during HFOV to evaluate Raw in pediatric and adult patients. An experiment was performed with a 3100B high-frequency oscillator, a physical model of the respiratory system, and a pressure and flow measurement system. The physical model with different combinations of resistance and compliance was ventilated during the experiment. The resistance Rrs was calculated from the impedance of the physical model, which was determined from the spectral density of the pressure at airway opening and the spectral cross-density of the gas flow and pressure at airway opening. Rrs of the model increased with an added resistor and did not change significantly with a change in compliance. The method is feasible for monitoring respiratory system resistance during HFOV and has the potential to optimize CDP settings during HFOV in clinical practice.

Frühgeborene: Nasale Hochfrequenz-Oszillationsbeatmung vs. nasaler CPAP

Viele Frühgeborene mit einem Atemnotsyndrom (engl. Respiratory Distress Syndrome, RDS) erhalten zunächst eine nicht invasive Atemunterstützung. Ein chinesisches Forscherteam untersuchte nun, welche Methode besser vor einem invasiven mechanischen Beatmungsbedarf schützte: Der nasale CPAP (Continuous Positive Airway Pressure) oder die nasale HFOV (High-Frequency Oscillatory Ventilation).

31 Noninvasive high-frequency oscillatory ventilation in preterm infants: Safe and effective

Primary Subject area Neonatal-Perinatal Medicine Background Mechanical ventilation is frequently used in preterm infants for various indications, but is associated with multiple complications, including bronchopulmonary dysplasia and poorer neurodevelopmental outcomes. Noninvasive high-frequency oscillatory ventilation (nHFOV) is a noninvasive ventilation (NIV) strategy used to avoid mechanical ventilation and associated complications. However, its effectiveness remains controversial, and its safety has not been established. Objectives The objectives were to evaluate the effectiveness of nHFOV to prevent intubations and support adequate ventilation in preterm infants, and to assess its safety profile. Design/Methods This was a retrospective crossover case study including 24 infants and 30 nHFOV instances between May 2018 and June 2020. Infants were included if they were placed on nHFOV for at least one hour; each nHFOV trial contributed as one instance. Data was collected from health records. Effectiveness outcomes were: successful transition to another NIV mode without requiring intubation, and variations in CO2, FiO2, and number of spells. Safety outcomes were: apparition of intraventricular hemorrhage (IVH), gastrointestinal complications, nasal cutaneous trauma, and comfort as assessed with the Neonatal Pain, Agitation and Sedation Scale (N-PASS). Descriptive statistics were used for baseline characteristics. Nonparametric and semiparametric tests were used to compare outcomes pre- and during nHFOV. Results Baseline characteristics are presented in Table 1. At initiation of nHFOV, mean chronological age and weight were 24 days (95% CI: 20 – 28) and 1119 grams (95% CI: 1038 – 1200) respectively. The most frequent indication for nHFOV was spells (56.7%), and the mean duration of nHFOV instances was 3.9 days (95% CI: 2.7 – 5.1) (Table 1). In 18 (60%) cases, infants transitioned successfully to another NIV mode without requiring intubation. Levels of CO2 and number of spells were significantly lower during nHFOV than pre-nHFOV. There was no significant difference in FiO2 pre-nHFOV and during nHFOV. No apparition or progression of IVH was observed following the use of nHFOV. There was no significant difference in N-PASS, nasal trauma, and gastrointestinal complications pre-nHFOV and during nHFOV (Table 2). Conclusion This study suggests that nHFOV is an effective ventilation method to avoid intubation and to decrease spells in preterm infants, without increasing complications.