The Diaphragmatic Initiated Ventilatory Assist (DIVA) trial: study protocol for a randomized controlled trial comparing rates of extubation failure in extremely premature infants undergoing extubation to non-invasive neurally adjusted ventilatory assist versus non-synchronized nasal intermittent positive pressure ventilation

BACKGROUND

Invasive mechanical ventilation contributes to bronchopulmonary dysplasia (BPD), the most common complication of prematurity and the leading respiratory cause of childhood morbidity. Non-invasive ventilation (NIV) may limit invasive ventilation exposure and can be either synchronized or non-synchronized (NS). Pooled data suggest synchronized forms may be superior. Non-invasive neurally adjusted ventilatory assist (NIV-NAVA) delivers NIV synchronized to the neural signal for breathing, which is detected with a specialized catheter. The DIVA (Diaphragmatic Initiated Ventilatory Assist) trial aims to determine in infants born 240/7-276/7 weeks' gestation undergoing extubation whether NIV-NAVA compared to non-synchronized nasal intermittent positive pressure ventilation (NS-NIPPV) reduces the incidence of extubation failure within 5 days of extubation.

METHODS

This is a prospective, unblinded, pragmatic, multicenter phase III randomized clinical trial. Inclusion criteria are preterm infants 24-276/7 weeks gestational age who were intubated within the first 7 days of life for at least 12 h and are undergoing extubation in the first 28 postnatal days. All sites will enter an initial run-in phase, where all infants are allocated to NIV-NAVA, and an independent technical committee assesses site performance. Subsequently, all enrolled infants are randomized to NIV-NAVA or NS-NIPPV at extubation. The primary outcome is extubation failure within 5 days of extubation, defined as any of the following: (1) rise in FiO2 at least 20% from pre-extubation for > 2 h, (2) pH ≤ 7.20 or pCO2 ≥ 70 mmHg; (3) > 1 apnea requiring positive pressure ventilation (PPV) or ≥ 6 apneas requiring stimulation within 6 h; (4) emergent intubation for cardiovascular instability or surgery. Our sample size of 478 provides 90% power to detect a 15% absolute reduction in the primary outcome. Enrolled infants will be followed for safety and secondary outcomes through 36 weeks' postmenstrual age, discharge, death, or transfer.

DISCUSSION

The DIVA trial is the first large multicenter trial designed to assess the impact of NIV-NAVA on relevant clinical outcomes for preterm infants. The DIVA trial design incorporates input from clinical NAVA experts and includes innovative features, such as a run-in phase, to ensure consistent technical performance across sites.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov , trial identifier NCT05446272 , registered July 6, 2022.

Feasibility of Non-invasive Neurally Adjusted Ventilator Assist After Congenital Diaphragmatic Hernia Repair

BACKGROUND

The use of neurally adjusted ventilator assist (NAVA) in congenital diaphragmatic hernia (CDH) patients has been historically deemed unwise, since the trigger for breaths is the electromyographic activity of the diaphragmatic muscle. We report on our NAVA experience in CDH patients.

METHODS

We performed an IRB-approved retrospective review of newborns from 1/1/2012-1/1/2017 at a Level I Children's Surgery Center undergoing CDH repair. Data obtained included demographics, defect type and repair, respiratory support, and outcomes.

RESULTS

Seven infants with CDH were placed on noninvasive-NAVA (NIV-NAVA) after extubation. All seven patients underwent open transabdominal repair, with five requiring patch repair. All survived to discharge, and one year after birth. When we compared this group to a contemporary cohort of patients who also underwent CDH repair, we found no significant differences in birth weight, postmenstrual age, or gender. However, there was a significantly higher need for inhaled nitric oxide (p = 0.002), high frequency oscillatory ventilation (p = 0.016), and extracorporeal membranous oxygenation support (p = 0.045) in the NIV-NAVA cohort.

CONCLUSION

This is the first report of NIV-NAVA being successfully utilized as an adjunct to wean infants from conventional ventilation after CDH repair, even in those who require patch repair or with more significant disease severity.

LEVELS OF EVIDENCE

III- Retrospective Comparative Study.

Proportional assist ventilation versus pressure support ventilation in weaning ventilation: a pilot randomised controlled trial

OBJECTIVE

Proportional assist ventilation with load-adjustable gain factors (PAV+) is a mode of ventilation that provides assistance in proportion to patient effort. This may have physiological and clinical advantages when compared with pressure support ventilation (PSV). Our objective was to compare these two modes in patients being weaned from mechanical ventilation.

DESIGN

Prospective randomised controlled trial comparing PSV with PAV+.

SETTING

University-affiliated, tertiary referral intensive care unit (ICU).

PARTICIPANTS

Mechanically ventilated patients on a controlled mode of ventilation for at least 24 hours, who were anticipated to be spontaneously ventilated for at least 48 hours after randomisation.

INTERVENTIONS

Nil.

MAIN OUTCOME MEASURES

The primary outcome was time to successful liberation from the ventilator after the commencement of a spontaneous mode of ventilation. Secondary outcomes were requirement of rescue (mandatory) ventilation, requirement of sedative drugs, requirement for tracheostomy, re-intubation within 48 hours of extubation, ICU length of stay (LOS), hospital LOS, and ICU and hospital mortality.

RESULTS

50 patients were randomised to either PSV (n = 25) or PAV+ (n = 25). There was no significant difference between the PAV+ and PSV groups in time to successful weaning (84.3 v 135.9 hours, respectively; P = 0.536). Four patients randomised to PAV+ were crossed over to PSV during weaning. There was no significant difference between groups for rescue ventilation, reintubation within 48 hours, tracheostomy, sedatives and analgesics prescribed, and ICU and hospital LOS. ICU mortality was higher in the PSV group (25% v 4 %; P = 0.002).

CONCLUSIONS

Both modes of ventilation were comparable in time to liberation from the ventilator.

Neurally adjusted ventilatory assist compared to other forms of triggered ventilation for neonatal respiratory support

BACKGROUND

Effective synchronisation of infant respiratory effort with mechanical ventilation may allow adequate gas exchange to occur at lower peak airway pressures, potentially reducing barotrauma and volutrauma and development of air leaks and bronchopulmonary dysplasia. During neurally adjusted ventilatory assist ventilation (NAVA), respiratory support is initiated upon detection of an electrical signal from the diaphragm muscle, and pressure is provided in proportion to and synchronous with electrical activity of the diaphragm (EADi). Compared to other modes of triggered ventilation, this may provide advantages in improving synchrony.

OBJECTIVES

Primary• To determine whether NAVA, when used as a primary or rescue mode of ventilation, results in reduced rates of bronchopulmonary dysplasia (BPD) or death among term and preterm newborn infants compared to other forms of triggered ventilation• To assess the safety of NAVA by determining whether it leads to greater risk of intraventricular haemorrhage (IVH), periventricular leukomalacia, or air leaks when compared to other forms of triggered ventilation Secondary• To determine whether benefits of NAVA differ by gestational age (term or preterm)• To determine whether outcomes of cross-over trials performed during the first two weeks of life include peak pressure requirements, episodes of hypocarbia or hypercarbia, oxygenation index, and the work of breathing SEARCH METHODS: We performed searches of the Cochrane Central Register of Controlled Trials (CENTRAL) in the Cohrane Library; MEDLINE via Ovid SP (January 1966 to March 2017); Embase via Ovid SP (January 1980 to March 2017); the Cumulative Index to Nursing and Allied Health Literature (CINAHL) via EBSCO host (1982 to March 2017); and the Web of Science (1985 to 2017). We searched abstracts from annual meetings of the Pediatric Academic Societies (PAS) (2000 to 2016); meetings of the European Society of Pediatric Research (published in Pediatric Research); and meetings of the Perinatal Society of Australia and New Zealand (PSANZ) (2005 to 2016). We also searched clinical trials databases to March 2017.

SELECTION CRITERIA

We included randomised and quasi-randomised clinical trials including cross-over trials comparing NAVA with other modes of triggered ventilation (assist control ventilation (ACV),synchronous intermittent mandatory ventilation plus pressure support (SIMV ± PS), pressure support ventilation (PSV), or proportional assist ventilation (PAV)) used in neonates.

DATA COLLECTION AND ANALYSIS

Primary outcomes of interest from randomised controlled trials were all-cause mortality, bronchopulmonary dysplasia (BPD; defined as oxygen requirement at 28 days), and a combined outcome of all-cause mortality or BPD. Secondary outcomes were duration of mechanical ventilation, incidence of air leak, incidence of IVH or periventricular leukomalacia, and survival with an oxygen requirement at 36 weeks' postmenstrual age.Outcomes of interest from cross-over trials were maximum fraction of inspired oxygen, mean peak inspiratory pressure, episodes of hypocarbia, and episodes of hypercarbia measured across the time period of each arm of the cross-over. We planned to assess work of breathing; oxygenation index, and thoraco-abdominal asynchrony at the end of the time period of each arm of the cross-over study.

MAIN RESULTS

We included one randomised controlled study comparing NAVA versus patient-triggered time-cycled pressure-limited ventilation. This study found no significant difference in duration of mechanical ventilation, nor in rates of BPD, pneumothorax, or IVH.

AUTHORS' CONCLUSIONS

Risks and benefits of NAVA compared to other forms of ventilation for neonates are uncertain. Well-designed trials are required to evaluate this new form of triggered ventilation.

Feasibility and physiological effects of noninvasive neurally adjusted ventilatory assist in preterm infants

BackgroundNoninvasive neurally adjusted ventilator assist (NIV-NAVA) was introduced to our clinical practice via a pilot and a randomized observational study to assess its safety, feasibility, and short-term physiological effects.MethodsThe pilot protocol applied NIV-NAVA to 11 infants on nasal CPAP, high-flow nasal cannula, or nasal intermittent mandatory ventilation (NIMV), in multiple 2- to 4-h periods of NIV-NAVA for comparison. This provided the necessary data to design a randomized, controlled observational crossover study in eight additional infants to compare the physiological effects of NIV-NAVA with NIMV during 2-h steady-state conditions. We recorded the peak inspiratory pressure (PIP), FiO2, Edi, oxygen saturations (histogram analysis), transcutaneous PCO2, and movement with an Acoustic Respiratory Movement Sensor.ResultsThe NAVA catheter was used for 81 patient days without complications. NIV-NAVA produced significant reductions (as a percentage of measurements on NIMV) in the following: PIP, 13%; FiO2, 13%; frequency of desaturations, 42%; length of desaturations, 32%; and phasic Edi, 19%. Infant movement and caretaker movement were reduced by 42% and 27%, respectively. Neural inspiratory time was increased by 39 ms on NIV-NAVA, possibly due to Head's paradoxical reflex.ConclusionNIV-NAVA was a safe, alternative mode of noninvasive support that produced beneficial short-term physiological effects, especially compared with NIMV.

Non-invasive ventilation with intelligent volume-assured pressure support versus pressure-controlled ventilation: effects on the respiratory event rate and sleep quality in COPD with chronic hypercapnia

BACKGROUND

COPD patients who develop chronic hypercapnic respiratory failure have a poor prognosis. Treatment of choice, especially the best form of ventilation, is not well known.

OBJECTIVES

This study compared the effects of pressure-controlled (spontaneous timed [ST]) non-invasive ventilation (NIV) and NIV with intelligent volume-assured pressure support (IVAPS) in chronic hypercapnic COPD patients regarding the effects on alveolar ventilation, adverse patient/ventilator interactions and sleep quality.

METHODS

This prospective, single-center, crossover study randomized patients to one night of NIV using ST then one night with the IVAPS function activated, or vice versa. Patients were monitored using polysomnography (PSG) and transcutaneous carbon dioxide pressure (PtcCO2) measurement. Patients rated their subjective experience (total score, 0-45; lower scores indicate better acceptability).

RESULTS

Fourteen patients were included (4 females, age 59.4±8.9 years). The total number of respiratory events was low, and similar under pressure-controlled (5.4±6.7) and IVAPS (8.3±10.2) conditions (P=0.064). There were also no clinically relevant differences in PtcCO2 between pressure-controlled and IVAPS NIV (52.9±6.2 versus 49.1±6.4 mmHg). Respiratory rate was lower under IVAPS overall; between-group differences reached statistical significance during wakefulness and non-rapid eye movement sleep. Ventilation pressures were 2.6 cmH2O higher under IVAPS versus pressure-controlled ventilation, resulting in a 20.1 mL increase in breathing volume. Sleep efficiency was slightly higher under pressure-controlled ventilation versus IVAPS. Respiratory arousals were uncommon (24.4/h [pressure-controlled] versus 25.4/h [IVAPS]). Overall patient assessment scores were similar, although there was a trend toward less discomfort during IVAPS.

CONCLUSION

Our results show that IVAPS NIV allows application of higher nocturnal ventilation pressures versus ST without affecting sleep quality or inducing ventilation- associated events.

Neurally adjusted ventilatory assist as an alternative to pressure support ventilation in adults: a French multicentre randomized trial

PURPOSE

Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that tailors the level of assistance delivered by the ventilator to the electromyographic activity of the diaphragm. The objective of this study was to compare NAVA and pressure support ventilation (PSV) in the early phase of weaning from mechanical ventilation.

METHODS

A multicentre randomized controlled trial of 128 intubated adults recovering from acute respiratory failure was conducted in 11 intensive care units. Patients were randomly assigned to NAVA or PSV. The primary outcome was the probability of remaining in a partial ventilatory mode (either NAVA or PSV) throughout the first 48 h without any return to assist-control ventilation. Secondary outcomes included asynchrony index, ventilator-free days and mortality.

RESULTS

In the NAVA and PSV groups respectively, the proportion of patients remaining in partial ventilatory mode throughout the first 48 h was 67.2 vs. 63.3 % (P = 0.66), the asynchrony index was 14.7 vs. 26.7 % (P < 0.001), the ventilator-free days at day 7 were 1.0 day [1.0-4.0] vs. 0.0 days [0.0-1.0] (P < 0.01), the ventilator-free days at day 28 were 21 days [4-25] vs. 17 days [0-23] (P = 0.12), the day-28 mortality rate was 15.0 vs. 22.7 % (P = 0.21) and the rate of use of post-extubation noninvasive mechanical ventilation was 43.5 vs. 66.6 % (P < 0.01).

CONCLUSIONS

NAVA is safe and feasible over a prolonged period of time but does not increase the probability of remaining in a partial ventilatory mode. However, NAVA decreases patient-ventilator asynchrony and is associated with less frequent application of post-extubation noninvasive mechanical ventilation.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02018666.

The Esophageal Pressure-Guided Ventilation 2 (EPVent2) trial protocol: a multicentre, randomised clinical trial of mechanical ventilation guided by transpulmonary pressure

INTRODUCTION

Optimal ventilator management for patients with acute respiratory distress syndrome (ARDS) remains uncertain. Lower tidal volume ventilation appears to be beneficial, but optimal management of positive end-expiratory pressure (PEEP) remains unclear. The Esophageal Pressure-Guided Ventilation 2 Trial (EPVent2) aims to examine the impact of mechanical ventilation directed at maintaining a positive transpulmonary pressure (PTP) in patients with moderate-to-severe ARDS.

METHODS AND ANALYSIS

EPVent2 is a multicentre, prospective, randomised, phase II clinical trial testing the hypothesis that the use of a PTP-guided ventilation strategy will lead to improvement in composite outcomes of mortality and time off the ventilator at 28 days as compared with a high-PEEP control. This study will enrol 200 study participants from 11 hospitals across North America. The trial will utilise a primary composite end point that incorporates death and days off the ventilator at 28 days to test the primary hypothesis that adjusting ventilator pressure to achieve positive PTP values will result in improved mortality and ventilator-free days.

ETHICS AND DISSEMINATION

Safety oversight will be under the direction of an independent Data and Safety Monitoring Board (DSMB). Approval of the protocol was obtained from the DSMB prior to enrolling the first study participant. Approvals of the protocol as well as informed consent documents were also obtained from the Institutional Review Board of each participating institution prior to enrolling study participants at each respective site. The findings of this investigation, as well as associated ancillary studies, will be disseminated in the form of oral and abstract presentations at major national and international medical specialty meetings. The primary objective and other significant findings will also be presented in manuscript form. All final, published manuscripts resulting from this protocol will be submitted to PubMed Central in accordance with the National Institute of Health Public Access Policy.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov under number NCT01681225.