Non-invasive High Frequency Ventilation Research Articles

Noninvasive High Frequency Ventilation as a Post-extubation Respiratory Support in Preterm Neonates

Abstract Background Noninvasive mechanical ventilation aims to provide respiratory support without the pulmonary and non-pulmonary complications associated with invasivemechanical ventilation including infection, subglottic stenosis, air leak syndrome and bronchopulmonary dysplasia (BPD). There is a notable increase in use of various types of noninvasive respiratory support post extubation to ensure the sucesss of extubation and avoid re-intubation. Noninvasive high frequency ventilation (NHFOV) is a new mode of noninvasive ventilation which is achieved through the use of noninvasive continuous flow with superimposed oscillations combining the benefits of high frequency oscillatory ventilaltion and noninvasive ventilation. Aim of Work The primary aim of the study is to compare re-ventilation rate between noninvasive positive pressure ventilation (NIPPV) and NHFOV when used as post extubation respiratory support. Secondary aim was to compare workof breathing, chest X-ray grade, incidence of pneumothorax and duration to reach full enteral intake between the 2 groups. Methodology Sixty preterm neonates with respiratory distress syndrome (RDS) who received invasive mechanical ventilation for more than 48 hours were included in this randomized controlled trial. Patients were randomly allocated post-extubation toNIPPV or NHFOV. The 2 groups were matched regarding weight, gestational age and comorbidities during invasive ventilation. Patients were compared regarding re-ventilation rate, work of breathing assessed by Downes score, chest X-ray grade, incidence of pneumothorax and duration to reach full enteral intake. Results Lower re-ventilation rate was found in NHFOV group (23.3%) compared to NIPPV group (30.0%). Median duration to reach full intake was shorter in NHFOV group (8 days) compared to NIPPV group (9.5 days) however, theseresults didn’t reach statistically significant difference (P value = 0.559 value and0.299 respectively). No difference was found between studied groups regarding work of breathing assessed by Downes’ score (P value = 0.634) nor regarding chest X-ray grades (p value= 0.902). Incidence of pneumothorax was equal in NHFOV group compared to NIPPV group with p value of 0.313. Conclusion NHFOV is a promising safe noninvasive mode for neonates post-extubation.

Neonatal high frequency ventilation: Current trends and future directions

High frequency ventilation (HFV) in neonates has been in use for over forty years. Some early HFV ventilators are no longer available, but high frequency oscillatory ventilation (HFOV) and jet ventilators (HFJV) continue to be commonly employed. Advanced HFOV models available outside of the United States are much quieter and easier to use, and are available as options on many conventional ventilators, providing important improvements such as tidal volume measurement and targeting. HFJV excels in treating air leak and non-homogenous lung disease and is often used for other diseases as well. High frequency non-invasive ventilation (hfNIV) is a novel application of HFV that remains under investigation. Similar to bubble CPAP, hfNIV has been applied with a variety of high-frequency ventilators. Efficacy and safety of hfNIV with any device have not yet been established. This article describes the current approaches to these HFV therapies and stresses the importance of understanding how each device works and what disease processes may respond best to the technology employed.

Lung CT stabilization with high-frequency non-invasive ventilation (HF-NIV) and breath-hold (BH) in lung nodule assessment by PET/CT

PurposeTo evaluate the effect of lung stabilization using high-frequency non-invasive ventilation (HF-NIV) and breath-hold (BH) techniques on lung nodule detection and texture assessment in PET/CT compared to a free-breathing (FB) standard lung CT acquisition in PET/CT.Materials and methodsSix patients aged 65 ± 7 years, addressed for initial assessment of at least one suspicious lung nodule with 18F-FDG PET/CT, underwent three consecutive lung PET/CT acquisitions with FB, HF-NIV and BH. Lung nodules were assessed on all three CT acquisitions of the PET/CT and characterized for any size, volume and solid/sub-solid nature.ResultsBH detected a significantly higher number of nodules (n = 422) compared to HF-NIV (n = 368) and FB (n = 191) (p < 0.001). The mean nodule size (mm) was 2.4 ± 2.1, 2.6 ± 1.9 and 3.2 ± 2.4 in BH, HF-NIV and FB, respectively, for long axis and 1.5 ± 1.3, 1.6 ± 1.2 and 2.1 ± 1.7 in BH, HF-NIV and FB, respectively, for short axis. Long- and short-axis diameters were significantly different between BH and FB (p < 0.001) and between HF-NIV and FB (p < 0.001 and p = 0.008), but not between BH and HF-NIV. A trend for higher volume was shown in FB compared to BH (p = 0.055) and HF-NIV (p = 0.068) without significant difference between BH and HF-NIV (p = 1). We found a significant difference in detectability of sub-solid nodules between the three acquisitions, with BH showing a higher number of sub-solid nodules (n = 128) compared to HF-NIV (n = 72) and FB (n = 44) (p = 0.002).ConclusionWe observed a higher detection rate of pulmonary nodules on CT under BH or HF-NIV conditions applied to PET/CT than with FB. BH and HF-NIV demonstrated comparable texture assessment and performed better than FB in assessing size and volume. BH showed a better performance for detecting sub-solid nodules compared to HF-NIV and FB. The addition of BH or HF-NIV to PET/CT can help improve the detection and texture characterization of lung nodules by CT, therefore improving the accuracy of oncological lung disease assessment. The ease of use of BH and its added value should prompt its use in routine practice.

PO-1056 Quantification of diaphragm motion with ultrasound during non-invasive high frequency ventilation

PO-1056 Quantification of diaphragm motion with ultrasound during non-invasive high frequency ventilation

14 Diaphragmatic Electrical Activity in Preterm Infants on Non-Invasive High Frequency Oscillatory Ventilation (DEAP-NHFO Study)

Abstract Primary Subject area Neonatal-Perinatal Medicine Background Continuous Positive Airway Pressure (CPAP) is a common form of non-invasive respiratory support for preterm infants. Non-invasive high frequency ventilation (NHFOV) is a relatively new method of non-invasive respiratory support. NHFOV is being increasingly utilized in clinical practice in an attempt to prevent intubation and minimize ventilator-induced lung injury in preterm infants. Preliminary studies suggest superiority of NHFOV over CPAP, but little is known about its mechanism of action and its effect on respiratory control in the newborn. We hypothesize that NHFOV reduces respiratory drive and improves ventilation, resulting in decreased patient diaphragm energy expenditure, which can be assessed by measuring the electrical activity of the diaphragm (Edi). Objectives The objective of this study is to compare the effects of non-invasive respiratory support delivered by nasal CPAP versus NHFOV on respiratory pattern, as assessed by the Edi in very low birth weight (VLBW) preterm infants. Design/Methods In a prospective, randomized, crossover study, 20 preterm infants with birth weights ≤1500 g requiring CPAP were randomized to either NHFOV or CPAP for 105 min, followed by crossover to the other method for the same duration. Edi was continuously measured by a feeding catheter with miniaturized sensors embedded in its wall (Maquet, Solna). The general sequence was 15 minutes for acclimation to the mode, 75 minutes for a feed to be completed, followed by 15 minutes for breath-by-breath analyses of neural breathing pattern. Primary outcome was difference in the peak Edi between CPAP and NHFOV. Secondary outcomes included difference in other measures of respiratory drive: neural respiratory rate, neural inspiratory time, diaphragm energy expenditure, transcutaneous pCO2, number of apnea episodes on the Edi, and episodes of clinically significant apnea. Results No significant differences in Edi timing, Edi min, Edi peak, apnea, or CO2 were observed between the two modes of respiratory support. Conclusion In this cohort of VLBW preterm infants, neural respiratory pattern was not significantly different between NHFOV and CPAP. With this baseline information in stable preterm infants, it would now be important to assess whether these results hold true in infants with more severe lung disease, where NHFOV is often used as escalating support from CPAP.

Management of Preterm Infants with Respiratory Distress Syndrome Using Non-Invasive High Frequency Ventilation versus Nasal Continuous Positive Airway Pressure

Background: Preterm infants have a risk of the respiratory distress syndrome (RDS). Helpful effects of high-frequency ventilators have been shown within management of RDS as well as the use of these ventilators as the initial mode of support or as a rescue treatment once failure of standard mechanical ventilation. Objective: This study aimed to compare between the nasal high-frequency oscillatory ventilation (nHFOV) and nasal continuous positive airway pressure (NCPAP) in the treatment of preterm infants with RDS in. Patients and methods: A study included 62 neonates with respiratory distress syndrome and was conducted at neonatal intensive care unit, Pediatrics Department, Zagazig University Hospital. Cases were divided into; group (A) was managed with non-invasive high frequency nasal ventilation and group (B) was managed with nasal continuous positive airway pressure. All cases were subjected to full medical history, clinical assessment, laboratory investigations and Silverman Score for respiratory distress grading. Results: There was statistically non-significant difference between the studied groups regarding occurrence of nasal injury, oxygen supply after study and need for use of surfactant. There was statistically non-significant difference between the studied groups regarding x ray findings before or by the end of the study. There was statistically significant relation between gestational age groups and need for surfactant in NHFV group. Conclusion: Noninvasive high frequency ventilation (NHFV) represent a better primary non-invasive mode than NCPAP in treatment of preterm infants with RDS.

Transmission of Oscillatory Volumes into the Preterm Lung during Noninvasive High-Frequency Ventilation.

Rationale: There is increasing evidence for a clinical benefit of noninvasive high-frequency oscillatory ventilation (nHFOV) in preterm infants. However, it is still unknown whether the generated oscillations are effectively transmitted to the alveoli.Objectives: To assess magnitude and regional distribution of oscillatory volumes (VOsc) at the lung level.Methods: In 30 prone preterm infants enrolled in a randomized crossover trial comparing nHFOV with nasal continuous positive airway pressure, electrical impedance tomography recordings were performed. During nHFOV, the smallest amplitude to achieve visible chest wall vibration was used, and the frequency was set at 8 hertz.Measurements and Main Results: Thirty consecutive breaths during artifact-free tidal ventilation were extracted for each of the 228 electrical impedance tomography recordings. After application of corresponding frequency filters, Vt and VOsc were calculated. There was a signal at 8 and 16 Hz during nHFOV, which was not detectable during nasal continuous positive airway pressure, corresponding to the set oscillatory frequency and its second harmonic. During nHFOV, the mean (SD) VOsc/Vt ratio was 0.20 (0.13). Oscillations were more likely to be transmitted to the non-gravity-dependent (mean difference [95% confidence interval], 0.041 [0.025-0.058]; P < 0.001) and right-sided lung (mean difference [95% confidence interval], 0.040 [0.019-0.061]; P < 0.001) when compared with spontaneous Vt.Conclusions: In preterm infants, VOsc during nHFOV are transmitted to the lung. Compared with the regional distribution of tidal breaths, oscillations preferentially reach the right and non-gravity-dependent lung. These data increase our understanding of the physiological processes underpinning nHFOV and may lead to further refinement of this novel technique.

Lung MRI assessment with high-frequency noninvasive ventilation at 3 T

PurposeTo investigate three MR pulse sequences under high-frequency noninvasive ventilation (HF-NIV) at 3 T and determine which one is better-suited to visualize the lung parenchyma. MethodsA 3D ultra-short echo time stack-of spirals Volumetric Interpolated Breath-hold Examination (UTE Spiral VIBE), without and with prospective gating, and a 3D double-echo UTE sequence with spiral phyllotaxis trajectory (3D radial UTE) were performed at 3 T in ten healthy volunteers under HF-NIV. Three experienced radiologists evaluated visibility and sharpness of normal anatomical structures, artifacts assessment, and signal and contrast ratio computation. The median of the three readers‘scores was used for comparison, p < .05 was considered statistically significant. Incidental findings were recorded and reported. ResultsThe 3D radial UTE resulted in less artifacts than the non-gated and gated UTE Spiral VIBE in inferior (score 3D radial UTE = 3, slight artifact without blurring vs. score UTE Spiral VIBE non-gated and gated = 2, moderate artifact with blurring of anatomical structure, p = .018 and p = .047, respectively) and superior lung regions (score 3D radial UTE = 3, vs. score UTE Spiral VIBE non-gated = 2.5, p = .48 and score UTE Spiral VIBE gated = 1, severe artifact with no normal structure recognizable, p = .014), and higher signal and contrast ratios (p = .002, p = .093). UTE Spiral VIBE sequences provided higher peripheral vasculature visibility than the 3D radial UTE (94.4% vs 80.6%, respectively, p < .001). The HF-NIV was well tolerated by healthy volunteers who reported on average minor discomfort. In three volunteers, 12 of 18 nodules confirmed with low-dose CT were identified with MRI (average size 2.6 ± 1.2 mm). ConclusionThe 3D radial UTE provided higher image quality than the UTE Spiral VIBE. Nevertheless, a better nodule assessment was noticed with the UTE Spiral VIBE that might be due to better peripheral vasculature visibility, and requires confirmation in a larger cohort.

Clinical application of noninvasive high-frequency ventilation in neonatal respiratory support

Noninvasive high-frequency ventilation (NIHFV) is a new form of noninvasive ventilation which distends positive pressure continuously with oscillations superimposed on spontaneous tidal breathing, through a noninvasive interface.NIHFV, which provides the advantages of nasal continuous positive airway pressure and high frequency ventilation, can rapidly improve oxygenation, effectively remove carbon dioxide, and does not require synchronous techno-logy.It is considered as a new and effective noninvasive ventilation mode.In this paper, the application of NIHFV to neonates were reviewed, including mechanics of gas exchange, research advances and approach to the use of NIHFV. Key words: Noninvasive high-frequency ventilation; Infant, newborn; Respiratory failure; Noninvasive respiratory support

Ultrashort echo time imaging of the lungs under high-frequency noninvasive ventilation: A new approach to lung imaging.

BackgroundAlthough ultrashort echo time (UTE) sequences allow excellent assessment of lung parenchyma, image quality remains lower than that of computed tomography (CT).PurposeTo investigate a high‐frequency noninvasive ventilation (HF‐NIV) technique allowing a stabilized inspiration and to compare image quality with current dedicated MR sequences.Study TypeProspective.PopulationTen healthy volunteers.Field Strength/Sequence3D radial UTE sequence at 1.5T.AssessmentUTE‐HF‐NIV sequence was compared with UTE‐free‐breathing (UTE‐FB), reconstructed at end expiration (UTE‐Exp) and average (UTE‐Avg), and breath‐hold VIBE sequences. The distance from lung apex to the dome of the right hemidiaphragm was measured. Visual assessment of the visibility and sharpness of normal anatomical structures was carried out. Dedicated software also quantitatively evaluated vessel–lung and right lung–liver interface sharpness. Apparent signal ratio (Sr) and contrast ratios (Cr) were quantitatively evaluated.Statistical TestsWilcoxon signed rank test for visual scores, paired t‐test for continuous variables, significance at P < 0.05.ResultsThe distance between apex and the right hemidiaphragmatic dome was significantly larger (P < 0.001) with UTE‐HF‐NIV compared with UTE‐FB and VIBE acquisitions. Vessel and airway visibility had identical median visual scores with all UTE methods. Median visual scores for sharpness of vessels and airways were significantly higher (P < 0.001) with HF‐NIV (vessels = 3; airways = 2) than in UTE‐FB (vessels = 2; airways = 1) and VIBE (vessels = 1; airways = 1). Software‐based vessel sharpness evaluation resulted in larger values in 8/10 volunteers with UTE‐HF‐NIV (67.3 ± 9.8) compared with UTE‐Avg (62.3 ± 12.6) but the average difference was not significant (P = 0.28). The sharpness of the lung–liver interface was significantly higher (P < 0.001) with HF‐NIV (17.3 ± 5.3) compared with UTE‐Avg (14.1 ± 3.9). Significantly higher values (P < 0.01) of Sr and Cr were observed with UTE‐HF‐NIV compared with UTE‐FB and VIBE.Data ConclusionHF‐NIV allowing acquisition at full inspiration significantly improves image quality for lung imaging. This could offer the option to alternate some follow‐up CT studies by using this technique. Level of Evidence: 2 Technical Efficacy: Stage 1J. Magn. Reson. Imaging 2019;50:1789–1797.

Response to 'Non-invasive high frequency ventilation and the errors from the past: designing simple trials neglecting complex respiratory physiology'.

Response to ‘Non-invasive high frequency ventilation and the errors from the past: designing simple trials neglecting complex respiratory physiology’

Non-invasive high-frequency ventilation versus bi-phasic continuous positive airway pressure (BP-CPAP) following CPAP failure in infants

Non-invasive high-frequency ventilation (NIHFV), a relatively new modality, is gaining popularity despite limited data. We sought to evaluate the effectiveness of NIHFV versus bi-phasic continuous positive airway pressure (BP-CPAP) in preterm infants failing CPAP. Infants with BW<1250 g on CPAP were randomly assigned to NIHFV or BP-CPAP if they met pre-determined criteria for CPAP failure. Infants were eligible for randomization after 72 h age and until 2000 g. Guidelines for adjustment of settings and criteria for failure of assigned mode were implemented. The primary aim was to assess feasibility of a larger trial. In addition, failure of assigned non-invasive respiratory support (NRS) mode, invasive mechanical ventilation (MV) 72 h and 7 days post-randomization, and bronchopulmonary dysplasia (BPD) were assessed. Thirty-nine infants were randomized to NIHFV (N=16) or BP-CPAP (N=23). There were no significant differences in mean (s.d.) postmenstrual age (28.6 (1.5) versus 29.0 (2.3) weeks, P=0.47), mean (s.d.) weight at randomization (965.0 (227.0) versus 958.1 (310.4) g, P=0.94) or other baseline demographics between the groups. Failure of assigned NRS mode was lower with NIHFV (37.5 versus 65.2%, P=0.09), although not statistically significant. There were no differences in rates of invasive MV 72 h and 7 days post-randomization or BPD. NIHFV was not superior to BP-CPAP in this pilot study. Effectiveness of NIHFV needs to be proven in larger multi-center, appropriately powered trials before widespread implementation.

5: Non-Invasive High Frequency Ventilation versus bi-phasic CPAP in Infants &lt;1250 Grams: A Pilot Randomized Controlled Trial

The use of non-invasive ventilation (NIV) modalities has increased in recent years in an effort to minimize lung injury among preterm infants. Non-invasive high frequency oscillatory ventilation (NIHFOV) is a relatively new modality that is gaining popularity despite limited clinical data. To evaluate the effectiveness of NIHFOV versus bi-phasic continuous positive airway pressure (BP-CPAP) in preterm infants who fail therapy with CPAP. Infants with birth-weight <1250 grams being managed on CPAP were randomly assigned to NIHFOV or BP-CPAP if they were to meet pre-determined criteria for CPAP failure. Infants were eligible only after 72 h of age, and as long as they were <2,000 grams at time of randomization, irrespective of previous respiratory support. Strict protocols for adjustment of settings as well as criteria for failure were implemented for both study arms. Primary outcome was failure of assigned NIV mode; secondary outcomes included need for endotracheal mechanical ventilation (EMV) at 72 h and 7 days post-randomization and bronchopulmonary dysplasia (BPD). Thirty infants were randomized to NIHFV (n=14) or BP-CPAP (n=16). There was no difference in postmenstrual age [28.9 (2.0) vs. 28.9 (2.1) weeks, P=0.68], weight at time of randomization [920 (220) vs. 1000 (300) grams, P=0.73] or other baseline demographics between NIHFV vs. BP-CPAP groups. Failure of assigned NIV mode was not statistically different, although the trend favoured NIHFV [42.9% vs. 62.5%, P=0.28]. There was no difference in the rates of EMV at 72 h and 7 days post-randomization or BPD rates, as shown in Table 1. Non-invasive high frequency ventilation was not superior to BP-CPAP in this pilot study, despite a trend towards lower failure rates. Larger, appropriately powered studies are warranted to confirm or refute the present findings.

RESPIRATORY SUPPORT OF PRETERM INFANTS AFTER EXTUBATION: COMPARISON OF CLINICAL EFFICACY OF STANDART AND HIGH FREQUENCY NON-INVASIVE VENTILATION

In animal models nasal high frequency oscillatory ventilation appears to provide better development of immature lung causing less injury. This open randomized study compared the clinical efficacy of the standard (SV) and high frequency (HFV) non-invasive (nasal) ventilation after primary extubation of very preterm infants. The study included 24 very premature infants with birth weight ≤1500 gand respiratory distress syndrome. Before the first extubation infants were randomized into the main (n = 12) or control (n = 12) group. A certain mode of respiratory support was used according to the protocol for at least 72 hrs. The primary study outcome was the need for re-intubation within 72 hrs after the initial extubation. Mortality, incidences of bronchopulmonary dysplasia (BPD) and other important complications of prematurity were also compared in these groups. The frequency of re-intubation within the first 72 hrs. of non-invasive respiratory support was similar in both groups (41.67%). No differences were observed between the groups for the total duration of respiratory support as well. The incidence of BPD was twice higher in the group of infants who were treated using nasal HFV (main group) according to physiological definition, but this difference was not significant (2 cases (16.67%) compared to 1 case (8.33%) accordingly; p = 0.78). BPD incidences according to the clinical definition were similar in the both groups (5 cases - 41.67%). The use of high-frequency non-invasive ventilation after primary extubation of very preterm infants has no obvious clinical advantages over the extubation followed by standard non-invasive ventilation.