Neurally adjusted ventilatory assist (NAVA) allows patient-ventilator synchrony during pediatric noninvasive ventilation: a crossover physiological study

Noninvasive Neurally Adjusted Ventilatory Assist in Infants With Bronchiolitis: Respiratory Outcomes in a Single-Center, Retrospective Cohort, 2016-2018

OBJECTIVES

To describe our experience of using noninvasive neurally adjusted ventilatory assist (NIV-NAVA) in infants with bronchiolitis, its association with the evolution of respiratory effort, and PICU outcomes.

DESIGN

Retrospective analysis of a prospectively curated, high-frequency electronic database.

SETTING

A PICU in a university-affiliated maternal-child health center in Canada.

PATIENTS

Patients younger than 2 years old who were admitted with a diagnosis of acute bronchiolitis and treated with NIV-NAVA from October 2016 to June 2018.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Patient characteristics, as well as respiratory and physiologic parameters, including electrical diaphragmatic activity (Edi), were extracted from the electronic database. Respiratory effort was estimated using the modified Wood Clinical Asthma Score (mWCAS) and the inspiratory Edi. A comparison in the respiratory effort data was made between the 2 hours before and 2 hours after starting NIV-NAVA. In the two seasons, 64 of 205 bronchiolitis patients were supported with NIV-NAVA. These 64 patients had a median (interquartile range [IQR]) age of 52 days (32-92 d), and there were 36 of 64 males. Treatment with NIV-NAVA was used after failure of first-tier noninvasive respiratory support; 25 of 64 patients (39%) had at least one medical comorbidity. NIV-NAVA initiation was associated with a moderate decrease in mWCAS from 3.0 (IQR, 2.5-3.5) to 2.5 (IQR, 2.0-3.0; p < 0.001). NIV-NAVA initiation was also associated with a statistically significant decrease in Edi ( p < 0.01). However, this decrease was only clinically relevant in infants with a 2-hour baseline Edi greater than 20 μV; here, the before and after Edi was 44 μV (IQR, 33-54 μV) compared with 27 μV (IQR, 21-36 μV), respectively ( p < 0.001). Overall, six of 64 patients (9%) required endotracheal intubation.

CONCLUSIONS

In this single-center retrospective cohort, in infants with bronchiolitis who were considered to have failed first-tier noninvasive respiratory support, the use of NIV-NAVA was associated with a rapid decrease in respiratory effort and a 9% intubation rate.

Monitoring the patient-ventilator asynchrony during non-invasive ventilation

Patient-ventilator asynchrony is a major issue during non-invasive ventilation and may lead to discomfort and treatment failure. Therefore, the identification and prompt management of asynchronies are of paramount importance during non-invasive ventilation (NIV), in both pediatric and adult populations. In this review, we first define the different forms of asynchronies, their classification, and the method of quantification. We, therefore, describe the technique to properly detect patient-ventilator asynchronies during NIV in pediatric and adult patients with acute respiratory failure, separately. Then, we describe the actions that can be implemented in an attempt to reduce the occurrence of asynchronies, including the use of non-conventional modes of ventilation. In the end, we analyzed what the literature reports on the impact of asynchronies on the clinical outcomes of infants, children, and adults.

New developments in neonatal respiratory management

Respiratory distress syndrome (RDS) is the major cause of respiratory failure in preterm infants due to immature lung development and surfactant deficiency. Although the concepts and methods of managing respiratory problems in neonates have changed continuously, determining appropriate respiratory treatment with minimal ventilation-induced lung injury and complications is crucially important. This review summarizes neonatal respiratory therapy's advances and available strategies (i.e., exogenous surfactant therapy, noninvasive ventilation, and different ventilation modes), focusing on RDS management.

Neurally Adjusted Ventilatory Assist in Newborns

Patient-ventilator asynchrony is very common in newborns. Achieving synchrony is quite challenging because of small tidal volumes, high respiratory rates, and the presence of leaks. Leaks also cause unreliable monitoring of respiratory metrics. In addition, ventilator adjustment must take into account that infants have strong vagal reflexes and demonstrate central apnea and periodic breathing, with a high variability in breathing pattern. Neurally adjusted ventilatory assist (NAVA) is a mode of ventilation whereby the timing and amount of ventilatory assist is controlled by the patient's own neural respiratory drive. As NAVA uses the diaphragm electrical activity (Edi) as the controller signal, it is possible to deliver synchronized assist, both invasively and noninvasively (NIV-NAVA), to follow the variability in breathing pattern, and to monitor patient respiratory drive, independent of leaks. This article provides an updated review of the physiology and the scientific literature pertaining to the use of NAVA in children (neonatal and pediatric age groups). Both the invasive NAVA and NIV-NAVA publications since 2016 are summarized, as well as the use of Edi monitoring. Overall, the use of NAVA and Edi monitoring is feasible and safe. Compared with conventional ventilation, NAVA improves patient-ventilator interaction, provides lower peak inspiratory pressure, and lowers oxygen requirements. Evidence from several studies suggests improved comfort, less sedation requirements, less apnea, and some trends toward reduced length of stay and more successful extubation.

Implementation of noninvasive neurally adjusted ventilatory assist in pediatric acute respiratory failure: a controlled before-after quality improvement study

Backgrounds

Pediatric noninvasive neurally adjusted ventilatory assist (NIV-NAVA) has been shown to improve patient-ventilator interaction but no data on clinical outcomes are available. Aim of this study was to compare NIV-NAVA with noninvasive pressure support (NIV-PS) in children with acute hypoxemic respiratory failure (AHRF), in a single-center before-after study. A cohort of thirty-four NIV-PS patients (before group) admitted to our PICU within the 2 years prior NAVA introduction was compared with a cohort of thirty children treated with NIV-NAVA during implementation phase (after group). The primary end-point was intubation rate between groups. Days on mechanical ventilation, number of invasive devices, nosocomial infections, PICU/hospital length of stay (LOS), and physiological parameters at 2 and 24 h after admission were considered.

Results

Intubation rate was lower in the NIV-NAVA group as compared to the NIV-PS group (p = 0.006). Patients treated with NIV-NAVA required fewer invasive devices (p = 0.032) and had lower incidence of ventilator-acquired pneumonia (p = 0.004) and shorter PICU (p = 0.032) and hospital LOS (p = 0.013). At 2 h, NIV-NAVA compared with NIV-PS resulted in higher paO₂:FIO₂ (p = 0.017), lower paCO₂ (p = 0.002), RR (p = 0.026), and HR (p = 0.009).

Conclusions

Early NIV-NAVA vs NIV-PS was associated to lower intubation rate and shorter PICU and hospital LOS. Further studies are needed in order to confirm these preliminary data.

Feasibility of neurally synchronized and proportional negative pressure ventilation in a small animal model

RATIONALE

Synchronized positive pressure ventilation is possible using diaphragm electrical activity (EAdi) to control the ventilator. It is unknown whether EAdi can be used to control negative pressure ventilation.

AIM

To evaluate the feasibility of using EAdi to control negative pressure ventilation.

METHODS

Fourteen anesthetized rats were studied (380-590 g) during control, resistive breathing, acute lung injury or CO₂ rebreathing. Positive pressure continuous neurally adjusted ventilatory assist (cNAVA^P+ ) was applied via intubation. Negative pressure cNAVA (cNAVA^P- ) was applied with the animal placed in a sealed box. In part 1, automatic stepwise increments in cNAVA level by 0.2 cmH₂ O/µV every 30 s was applied for cNAVA^P+ , cNAVA^P- , and a 50/50 combination of the two (cNAVA^P± ). In part 2: During 5-min ventilation with cNAVA^P+ or cNAVA^P- we measured circuit, box, and esophageal (Pes) pressure, EAdi, blood pressure, and arterial blood gases.

RESULTS

Part 1: During cNAVA^P+ , pressure in the circuit increased with increasing cNAVA levels, reaching a plateau, and similarly for cNAVA^P- , albeit reversed in sign. This was associated with downregulation of the EAdi. Pes swings became less negative with cNAVA^P+ but, in contrast, Pes swings were more negative during increasing cNAVA^P- levels. Increasing the cNAVA level during cNAVA^P± resulted in an intermediate response. Part 2: no significant differences were observed for box/circuit pressures, EAdi, blood pressure, or arterial blood gases. Pes swings during cNAVA^P- were significantly more negative than during cNAVA^P+ .

CONCLUSION

Negative pressure ventilation synchronized and proportional to the diaphragm activity is feasible in small animals.

Use of bilevel positive pressure ventilation in patients with bronchiolitis

RATIONAL

This study aims at describing the use of bilevel positive airway pressure (BiPAP) in infants with severe bronchiolitis.

WORKING HYPOTHESIS

The use of BiPAP in infants with bronchiolitis may be associated with a worst outcome.

STUDY DESIGN

A single-center retrospective study performed from October 2013 to April 2016.

METHODOLOGY

All infants from 1 day to 6 months of age admitted in the pediatric intensive care unit (PICU) were included if they had a clinical diagnosis of bronchiolitis and if they required any type of noninvasive ventilation (NIV), including high flow nasal cannula, continuous positive airway pressure and BiPAP at admission in PICU. There was no local written protocol regarding the ventilator management during the study.

RESULTS

Overall, 252 infants (median age 45 (26-72) days) were included in the study and 110 infants (44%) were supported by BiPAP at admission. More infants were born preterm in the group of patients supported by BiPAP at admission. No complication related to NIV occurred. Patients in the BiPAP group had a longer duration of noninvasive support as well as a longer PICU length of stay. However, hospital length of stay did not differ according to the type of respiratory support at admission.

CONCLUSION

The use of BiPAP was not associated with endotracheal intubation, however it was associated with increased PICU length of stay and increased duration of NIV.

Continuous neurally adjusted ventilation: a feasibility study in preterm infants

OBJECTIVES

To assess the feasibility and tolerance of NeuroPAP, a new non-invasive ventilation mode which continuously adjusts (during both inspiration and expiration) the pressure support proportionally to the diaphragm electrical activity (Edi), in preterm infants and to evaluate the impact on ventilation pressure and Edi.

DESIGN

Prospective cross-over single-centre feasibility study.

SETTING

One level 3 neonatal intensive care unit in Canada.

PATIENTS

Stable preterm infants ventilated with non-invasive positive pressure ventilation (NIPPV).

INTERVENTIONS

Subjects were successively ventilated in NIPPV with prestudy settings (30 min), in NeuroPAP with minimal pressure similar to NIPPV PEEP (positive end-expiratory pressure) (60 min), in NeuroPAP with minimal pressure reduced by 2 cmH₂0 (60 min), in continuous positive airway pressure (15 min) and again in NIPPV (30 min). Main outcome measures included tolerance, ventilation pressure, Edi and patient-ventilator synchrony.

RESULTS

Twenty infants born at 28.0±1.0 weeks were included. NeuroPAP was well tolerated and could be delivered during 100% of planned period. During NeuroPAP, the PEEP was continuously adjusted proportionally to tonic diaphragm Edi, although the average PEEP value was similar to the set minimal pressure. During NeuroPAP, 83 (78-86)% breaths were well synchronised vs 9 (6-12)% breaths during NIPPV (p<0.001).

CONCLUSIONS

NeuroPAP is feasible and well tolerated in stable preterm infants, and it allows transient adaptation in PEEP in response to tonic diaphragm electrical activity changes. Further studies are warranted to determine the impact of these findings on clinical outcomes.

TRIAL REGISTRATION NUMBER

NCT02480205.

Pressure Support Ventilation (PSV) versus Neurally Adjusted Ventilatory Assist (NAVA) in difficult to wean pediatric ARDS patients: a physiologic crossover study

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is an innovative mode for assisted ventilation that improves patient-ventilator interaction in children. The aim of this study was to assess the effects of patient-ventilator interaction comparing NAVA with pressure support ventilation (PSV) in patients difficult to wean from mechanical ventilation after moderate pediatric acute respiratory distress syndrome (PARDS).

METHODS

In this physiological crossover study, 12 patients admitted in the Pediatric Intensive Care Unit (PICU) with moderate PARDS failing up to 3 spontaneous breathing trials in less than 7 days, were enrolled. Patients underwent three study conditions lasting 1 h each: PSV1, NAVA and PSV2.

RESULTS

The Asynchrony Index (AI) was significantly reduced during the NAVA trial compared to both the PSV1 and PSV2 trials (p = 0.001). During the NAVA trial, the inspiratory and expiratory trigger delays were significantly shorter compared to those obtained during PSV1 and PSV2 trials (Delay_trinspp < 0.001, Delay_trexpp = 0.013). These results explain the significantly longer Time_sync observed during the NAVA trial (p < 0.001). In terms of gas exchanges, PaO₂ value significantly improved in the NAVA trial with respect to the PSV trials (p < 0.02). The PaO₂/FiO₂ ratio showed a significant improvement during the NAVA trial compared to both the PSV1 and PSV2 trials (p = 0.004).

CONCLUSIONS

In this specific PICU population, presenting difficulty in weaning after PARDS, NAVA was associated with a reduction of the AI and a significant improvement in oxygenation compared to PSV mode.

TRIAL REGISTRATION

ClinicalTrial.gov Identifier: NCT04360590 "Retrospectively registered".

Noninvasive Neurally Adjusted Ventilator Assist Ventilation in the Postoperative Period Produces Better Patient-Ventilator Synchrony but Not Comfort

Background

Noninvasive neurally adjusted ventilatory assist (NAVA) has been shown to improve patient-ventilator interaction in many settings. There is still scarce data with regard to postoperative patients indicated for noninvasive ventilation (NIV) which this study elates. The purpose of this trial was to evaluate postoperative patients for synchrony and comfort in noninvasive pressure support ventilation (NIV-PSV) vs. NIV-NAVA.

Methods

Twenty-two subjects received either NIV-NAVA or NIV-PSV in an object-blind, prospective, randomized, crossover fashion (observational trial). We evaluated blood gases and ventilator tracings throughout as well as comfort of ventilation at the end of each ventilation phase.

Results

There was an effective reduction in ventilator delays (p < 0.001) and negative pressure duration in NIV-NAVA as compared to NIV-PSV (p < 0.001). Although we used optimized settings in NIV-PSV, explaining the overall low incidence of asynchrony, NIV-NAVA led to reductions in the NeuroSync-index (p < 0.001) and all types of asynchrony except for double triggering that was significantly more frequent in NIV-NAVA vs. NIV-PSV (p = 0.02); ineffective efforts were reduced to zero by use of NIV-NAVA. In our population of previously lung-healthy subjects, we did not find differences in blood gases and patient comfort between the two modes.

Conclusion

In the postoperative setting, NIV-NAVA is well suitable for use and effective in reducing asynchronies as well as a surrogate for work of breathing. Although increased synchrony was not transferred into an increased comfort, there was an advantage with regard to patient-ventilator interaction. The trial was registered at the German clinical Trials Register (DRKS no.: DRKS00005408).

Implementation of Neurally Adjusted Ventilatory Assist (NAVA): Patient characteristics and staff experiences

OBJECTIVE

The objective of the study was to describe the implementation of Neurally Adjusted Ventilatory Assist (NAVA) by characteristics of patients receiving NAVA and by staff-experienced opportunities and barriers.

METHODS

Design. A retrospective review of hospital records of mechanically ventilated patients over two time periods after implementation, as well as a questionnaire survey and interviews with staff.

SETTING

A secondary Danish ICU.

PARTICIPANTS

ICU patients, nurses, and intensivists.

INTERVENTION

Implementation of NAVA, which included theoretical education, bedside training, and frequent updates.

MAIN OUTCOME MEASURE

Evaluation of NAVA implementation measured by characteristics of patients receiving NAVA and staff experiences with NAVA.

RESULTS

A total of 311 patients were included. Hereof 43 (27%) and 68 (44%) patients, respectively, had recieved NAVA. The patients receiving NAVA had higher severity scores and more hours on ventilators. A total of 35 nurses (76%) and 16 physicians (64%) completed the questionnaire. Most clinicians found, to a high (43%) or very high (41%) degree, that NAVA was an effective therapy option. Furthermore, 77% did not experience any barriers regarding NAVA therapy. The main advantages experienced with NAVA were increased patient comfort, respiratory synchrony with the ventilator, and improved opportunities for monitoring patient respiratory performance. The main disadvantage was the need for additional theoretical and practical knowledge.

CONCLUSION

Despite staff experience of NAVA as a beneficial treatment option, more than half of the patients did not receive NAVA treatment two years after the start of its implementation. Implementation of a therapy which is substantially different to earlier practices is complicated.

Monitoring of Respiratory Muscle Function in Critically Ill Children

OBJECTIVES

This review discusses the different techniques used at the bedside to assess respiratory muscle function in critically ill children and their clinical applications.

DATA SOURCES

A scoping review of the medical literature on respiratory muscle function assessment in critically ill children was conducted using the PubMed search engine.

STUDY SELECTION

We included all scientific, peer-reviewed studies about respiratory muscle function assessment in critically ill children, as well as some key adult studies.

DATA EXTRACTION

Data extracted included findings or comments about techniques used to assess respiratory muscle function.

DATA SYNTHESIS

Various promising physiologic techniques are available to assess respiratory muscle function at the bedside of critically ill children throughout the disease process. During the acute phase, this assessment allows a better understanding of the pathophysiological mechanisms of the disease and an optimization of the ventilatory support to increase its effectiveness and limit its potential complications. During the weaning process, these physiologic techniques may help predict extubation success and therefore optimize ventilator weaning.

CONCLUSIONS

Physiologic techniques are useful to precisely assess respiratory muscle function and to individualize and optimize the management of mechanical ventilation in children. Among all the available techniques, the measurements of esophageal pressure and electrical activity of the diaphragm appear particularly helpful in the era of individualized ventilatory management.

Noninvasive Neurally Adjusted Ventilatory Assist Versus High Flow Cannula Support After Congenital Heart Surgery

BACKGROUND

Extubation failure rates for critical patients in pediatric intensive care units (ICUs) range from 5% to 29%. Noninvasive (NIV) ventilation has been shown to decrease extubation failure. We compared reintubation rates and outcomes of patients supported with NIV neurally adjusted ventilation assist (NAVA) versus historical controls supported with high-flow nasal cannula (HFNC).

METHODS

Case-control study of infants less than three months of age who underwent cardiac surgery and received NIV support after extubation from January 2011 to May 2017. All patients supported with NIV NAVA after it became available in September 2013 were compared to matched patients extubated to HFNC from prior to September 2013.

RESULTS

Forty-two patients identified for the NIV NAVA group were matched with 42 historical controls supported with HFNC. Groups had similar baseline characteristics based on rate of acute kidney injury, number of single ventricle patients, Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) category, age, weight, bypass time, and duration of intubation. There was no significant difference in reintubation rates within 72 hours (14.3% in the HFNC group and 16.7% in the NIV NAVA group, P = 1.0). Median duration from extubation to coming off NIV support was longer in the NIV NAVA group (3.6 days vs 0.6 days, P < .001). Median time from extubation to ICU discharge was longer in the NIV NAVA group (10.5 vs 6.8 days, P = .02), as was total postoperative ICU length of stay (LOS; 17.6 vs 12.2, P = .01).

CONCLUSIONS

Introduction of NIV NAVA for postextubation support did not reduce reintubation rates compared to HFNC. Further study is needed as adoption of NIV NAVA may prolong LOS.

Tracheal opening manoeuvre (PEEP-20) in a patient with bronchopulmonary dysplasia and severe tracheobronchomalacia with neurally adjusted ventilatory assist (NAVA)

Bronchopulmonary dysplasia (BPD) is occasionally associated with tracheobronchomalacia, and it is this combination that can lead to serious outcomes. The most severe cases require tracheostomies, ventilatory support and eventually even tracheal stents or surgery. Ventilation in patients with tracheomalacia is complicated without a good patient-ventilator synchrony; the neurally adjusted ventilatory assist (NAVA) mode is potentially beneficial in these cases. This case report presents a patient affected by BPD and severe tracheobronchomalacia who was tracheostomised and ventilated 24 hours a day and who suffered from episodes of airway collapse despite using the NAVA mode. It was necessary to increase the positive end-expiratory pressure to 20 cmH₂O (the PEEP-20 manoeuvre) for several minutes during an episode; this allowed the trachea to remain open and allowed us to optimise the patient's ventilation. This strategy has previously been described in a patient with tracheomalacia, reducing the frequency and need for sedation in the following episodes.

Is noninvasive neurally adjusted ventilatory assistance (NIV-NAVA) an alternative to NCPAP in preventing extubation failure in preterm infants?

Background: Prolonged use of mechanical ventilation is associated with some complications as high mortality and high morbidities as bronchopulmonary dysplasia, ventilator-associated pneumonia, and pneumothorax. However, extubation failure in preterm infants is still high (40-60%) in very low birth weight infants (VLBW). Noninvasive neurally adjusted ventilatory assistance (NIV-NAVA) is triggered by the diaphragmatic electrical activity through a nasogastric tube that synchronizes patient/ventilator respiration, cycle by cycle effectively shortening the assisted cycle trigger and the degree of ventilatory assistance, optimizing the effects of intermittent inspiratory pressure on nasal continuous positive airway pressure (NCPAP). This study aims to compare reintubation rates until 72 h after extubation in preterm infants of high risk for reintubation using NIV-NAVA or NCPAP. Methods: A retrospective study of chart review data collection was performed in a private tertiary hospital. The study was approved by the local institutional Ethics Committee. We included infants considered at high risk of reintubation (BW < 1000 grams; use of invasive mechanical ventilation (IMV) for at least 7 days; or previous extubation failure episode) and compared the two groups according to the type of respiratory support after extubation: 1) NCPAP (n = 32); or 2) NIV-NAVA (n = 17). Demographics data were collected, the primary outcome was reintubation rate until 72 h after extubation. Secondary outcome was time to reintubation, BPD rate, IVH grade ≥ III, pneumothorax and death. Results: There was no difference between both groups in demographic data. The reintubation rate decreased significantly in the NIV-NAVA group compared to NCPAP (50.0-11.7, p < 0.02) despite the significantly higher length of invasive mechanical ventilation (IMV) before extubation attempt in NIV-NAVA group (12.4 versus 5.5 days, p < 0.04). There was no difference between both groups in secondary outcomes. Conclusions: In this small retrospective cohort study, the use of NIV-NAVA as postextubation strategy was effective in reducing extubation failure within 72 hours in preterm infants when compared to traditional NCPAP.

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.

Neurally adjusted ventilatory assist in extremely low-birthweight infants

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is expected to improve respiratory outcomes in preterm infants, but it has not yet been evaluated. We investigated whether NAVA could improve respiratory outcomes and reduce sedation use in extremely low-birthweight infants (ELBWI).

METHODS

A retrospective cohort study was conducted based on patient charts at the Nagano Children's Hospital neonatal intensive care unit, Japan. Infants who were born at <27 weeks' gestation were included. We assessed the prevalence of bronchopulmonary dysplasia (BPD), home oxygen therapy (HOT), duration of intubation, and sedation use.

RESULTS

The NAVA group consisted of 14 ELBWI who were born at <27 weeks' gestation between September 2013 and September 2015. A total of 21 ELBWI born between September 2011 and September 2013, before NAVA implementation, served as the control group. There were no significant differences in the perinatal background characteristics between the two groups. For respiratory outcomes, no significant between-group differences were found in the prevalence of BPD and HOT or the duration of intubation. The total duration of sedation use was not significantly different between the two groups, but in the NAVA group, midazolam was discontinued in all cases after the infants were switched to NAVA.

CONCLUSIONS

NAVA was safe in preterm infants and had a similar effect to conventional mechanical ventilation with regard to respiratory outcomes and sedation use in the chronic phase; thus, NAVA could be used in the early phase, at least before BPD worsens to improve respiratory outcomes in ELBWI.

Dexmedetomidine is effective and safe during NIV in infants and young children with acute respiratory failure

BACKGROUND

Noninvasive ventilation (NIV) is increasingly utilized in infants and young children, though associated with high failure rates due to agitation and poor compliance, mostly if patient-ventilator synchronization is required.

METHODS

A retrospective cohort study was carried out in an academic pediatric intensive care unit (PICU). Dexmedetomidine (DEX) was infused as unique sedative in 40 consecutive pediatric patients (median age 16 months) previously showing intolerance and agitation during NIV application.

RESULTS

During NIV clinical application both COMFORT-B Score and Richmond Agitation-Sedation Scale (RASS) were serially evaluated. Four patients experiencing NIV failure, all due to pulmonary condition worsening, required intubation and invasive ventilation. 36 patients were successfully weaned from NIV under DEX sedation and discharged from PICU. All patients survived until home discharge.

CONCLUSION

Our data suggest that DEX may represent an effective sedative agent in infants and children showing agitation during NIV. Early use of DEX in infants/children receiving NIV for acute respiratory failure (ARF) should be considered safe and capable of improving NIV, thus permitting both lung recruitment and patient-ventilator synchronization.

Non-invasive ventilation practices in children across Europe

OBJECTIVES

To describe the diversity in practice in non-invasive ventilation (NIV) in European pediatric intensive care units (PICUs).

WORKING HYPOTHESIS

No information about the use of NIV in Pediatrics across Europe is currently available, and there might be a wide variability regarding the approach.

STUDY DESIGN

Cross-sectional electronic survey.

METHODOLOGY

The survey was distributed to the ESPNIC mailing list and to researchers in different European centers.

RESULTS

One hundred one units from 23 countries participated. All respondent units used NIV. Almost all PICUs considered NIV as initial respiratory support (99.1%), after extubation (95.5% prophylactically, 99.1% therapeutically), and 77.5% as part of palliative care. Overall NIV use outside the PICUs was 15.5% on the ward, 20% in the emergency department, and 36.4% during transport. Regarding respiratory failure cause, NIV was delivered in pneumonia (97.3%), bronchiolitis (94.6%), bronchospasm (75.2%), acute pulmonary edema (84.1%), upper airway obstruction (76.1%), and in acute respiratory distress syndrome (91% if mild, 53.1% if moderate, and 5.3% if severe). NIV use in asthma was less frequent in Northern European units in comparison to Central and Southern European PICUs (P = 0.007). Only 47.7% of the participants had a written protocol about NIV use. Bilevel NIV was applied mostly through an oronasal mask (44.4%), and continuous positive airway pressure through nasal cannulae (39.8%). If bilevel NIV was required, 62.3% reported choosing pressure support (vs assisted pressure-controlled ventilation) in infants; and 74.5% in older children.

CONCLUSIONS

The present study shows that NIV is a widespread technique in European PICUs. Practice across Europe is variable.

Monitoring patient-ventilator asynchrony

PURPOSE OF REVIEW

This article describes and discusses the importance of monitoring patient-ventilator asynchrony, and the advantages and limitations of the specific techniques available at the bedside to evaluate it.

RECENT FINDINGS

Signals provided by esophageal catheters (pressure or electromyogram) are the most reliable and accurate instruments to detect asynchronies. Esophageal signals (providing electrical activity of the diaphragm or/and esophageal pressure) have allowed the recent description of reverse triggering, a new kind of asynchrony, in which mechanical insufflation repeatedly triggers diaphragmatic contractions. However, the use of esophageal catheters is not widespread, and data on the prevalence and consequences of asynchronies are still scarce. The development of software solutions that continuously and automatically record breathing waveforms from the ventilator recording is emerging. Using this technology, recent data support the fact that asynchronies are frequent and may be negatively associated with outcome.

SUMMARY

The prevalence and consequences of asynchronies may be largely underestimated because of a frequent lack of monitoring. Dedicated software solutions that continuously and automatically detect asynchronies may allow both clinical research and clinical applications aimed at determining the effects of asynchronies and minimizing their incidence among critically ill patients.

An overview of mechanical ventilation in the intensive care unit

This article discusses the history, types and essential components of mechanical ventilation. It addresses the potential complications associated with mechanical ventilation and outlines the nurse's role in the recognition and prevention of such complications. This article provides an overview of some of the advances in mechanical ventilation and emphasises the importance of patient safety through an awareness of the associated risks and limiting or avoiding mechanical ventilation where possible.

Patient-ventilator asynchrony during conventional mechanical ventilation in children

Background

We aimed (1) to describe the characteristics of patient–ventilator asynchrony in a population of critically ill children, (2) to describe the risk factors associated with patient–ventilator asynchrony, and (3) to evaluate the association between patient–ventilator asynchrony and ventilator-free days at day 28.

Methods

In this single-center prospective study, consecutive children admitted to the PICU and mechanically ventilated for at least 24 h were included. Patient–ventilator asynchrony was analyzed by comparing the ventilator pressure curve and the electrical activity of the diaphragm (Edi) signal with (1) a manual analysis and (2) using a standardized fully automated method.

Results

Fifty-two patients (median age 6 months) were included in the analysis. Eighteen patients had a very low ventilatory drive (i.e., peak Edi < 2 µV on average), which prevented the calculation of patient–ventilator asynchrony. Children spent 27% (interquartile 22–39%) of the time in conflict with the ventilator. Cycling-off errors and trigger delays contributed to most of this asynchronous time. The automatic algorithm provided a NeuroSync index of 45%, confirming the high prevalence of asynchrony. No association between the severity of asynchrony and ventilator-free days at day 28 or any other clinical secondary outcomes was observed, but the proportion of children with good synchrony was very low.

Conclusion

Patient–ventilator interaction is poor in children supported by conventional ventilation, with a high frequency of depressed ventilatory drive and a large proportion of time spent in asynchrony. The clinical benefit of strategies to improve patient–ventilator interactions should be evaluated in pediatric critical care.

Comparison of Effort of Breathing for Infants on Nasal Modes of Respiratory Support

OBJECTIVE

To directly compare effort of breathing between high flow nasal cannula (HFNC), nasal intermittent mechanical ventilation (NIMV), and nasal continuous positive airway pressure (NCPAP).

STUDY DESIGN

This was a single center prospective cross-over study for patients <6 months in the cardiothoracic or pediatric intensive care unit receiving nasal noninvasive respiratory support after extubation. We measured effort of breathing using esophageal manometry with pressure-rate product (PRP) on all 3 modes. NIMV synchrony was determined by comparing patient efforts (esophageal manometry) with mechanically delivered breaths (spirometry in ventilator circuit). On NIMV, PRP and synchrony was also measured after adding a nasal clip on 26 patients.

RESULTS

Forty-two children were included. Median (IQR) age was 2 (0.5, 4) months. There was no difference in median PRP between HFNC 6 liters per minute, 355 (270,550), NIMV 12/5 cm H₂O, 341 (235, 472), and NCPAP 5 cm H₂O, 340 (245,506) (P?=?.33). Results were similar regardless of HFNC flow rate or NIMV inspiratory pressure. Median PRP on CPAP of 5 cm H₂O prior to extubation 255 (176, 375) was significantly lower than all postextubation values (P?<?.002). On NIMV, less than 50% of patient efforts resulted in a ventilator breath, which was not improved with a nasal clip (P?>?.07)). However, as NIMV synchrony improved (>60%), PRP on NIMV was lower than on HFNC.

CONCLUSIONS

For infants, effort of breathing is similar on HFNC, NIMV, and NCPAP after extubation, regardless of flow rate or inspiratory pressure. We speculate that bi-level NIMV may be superior if high levels of synchrony can be achieved.

Recent Advances in Pediatric Ventilatory Assistance

In this review on respiratory assistance, we aim to discuss the following recent advances: the optimization and customization of mechanical ventilation, the use of high-frequency oscillatory ventilation, and the role of noninvasive ventilation. The prevention of ventilator-induced lung injury and diaphragmatic dysfunction is now a key aspect in the management of mechanical ventilation, since these complications may lead to higher mortality and prolonged length of stay in intensive care units. Different physiological measurements, such as esophageal pressure, electrical activity of the diaphragm, and volumetric capnography, may be useful objective tools to help guide ventilator assistance. Companies that design medical devices including ventilators and respiratory monitoring platforms play a key role in knowledge application. The creation of a ventilation consortium that includes companies, clinicians, researchers, and stakeholders could be a solution to promote much-needed device development and knowledge implementation.

The intensive care medicine clinical research agenda in paediatrics

BACKGROUND

Intensive Care Medicine set us the task of outlining a global clinical research agenda for paediatric intensive care (PIC). In line with the clinical focus of this journal, we have limited this to research that may directly influence patient care.

METHODS

Clinician researchers from PIC research networks of varying degrees of formality from around the world were invited to answer two main questions: (1) What have been the major recent advances in paediatric critical care research? (2) What are the top 10 studies for the next 10 years?

RESULTS

(1) Inclusive databases are well established in many countries. These registries allow detailed observational studies and feasibility testing of clinical trial protocols. Recent trials are larger and more valuable, and (2) most common interventions in PIC are not evidenced-based. Clinical studies for the next 10 years should address this deficit, including: ventilation techniques and interfaces; fluid, transfusion and feeding strategies; optimal targets for vital signs; multiple organ failure definitions, mechanisms and treatments; trauma, prevention and treatment; improving safety; comfort of the patient and their family; appropriate care in the face of medical complexity; defining post-PICU outcomes; and improving knowledge generation and adoption, with novel trial design and implementation strategies. The group specifically highlighted the need for research in resource-limited environments wherein mortality remains often tenfold higher than in well-resourced settings.

CONCLUSION

Paediatric intensive care research has never been healthier, but many gaps in knowledge remain. We need to close these urgently. The impact of new knowledge will be greatest in resource-limited environments.

Combined use of Neurally Adjusted Ventilatory Assist (NAVA) and Vertical Expandable Prostethic Titanium Rib (VEPTR) in a patient with Spondylocostal dysostosis and associated bronchomalacia

Jarcho-Levin syndrome is a rare disorder characterised by defects in vertebral and costal segmentation of varying severity. Respiratory complications are the main cause of death or severe comorbidity due to a restrictive rib cage. A 3 months old infant with Spondylocostal dysostosis and associated bronchomalacia experiencing severe asynchrony during the weaning process is reported. The Neurally Adjusted Ventilatory Assist (NAVA) mode was used to improve adaptation to mechanical ventilation after Vertical Expandable Prosthetic Titanium Ribs (VEPTRs) were implanted. The synchrony achieved with the NAVA mode allowed a decrease of the sedoanalgesia he received. A follow-up CT scan showed a reduction in the volume of the posterobasal atelectasis. The evolution of this patient suggests that the combined use of VEPTR for thoracic expansion and ventilation using NAVA can favour the global improvement. This mode could be an option to consider in selected patients with difficult weaning from mechanical ventilation in paediatric intensive care units.

Early Noninvasive Neurally Adjusted Ventilatory Assist Versus Noninvasive Flow-Triggered Pressure Support Ventilation in Pediatric Acute Respiratory Failure: A Physiologic Randomized Controlled Trial

OBJECTIVE

Neurally adjusted ventilatory assist has been shown to improve patient-ventilator interaction in children with acute respiratory failure. Objective of this study was to compare the effect of noninvasive neurally adjusted ventilatory assist versus noninvasive flow-triggered pressure support on patient-ventilator interaction in children with acute respiratory failure, when delivered as a first-line respiratory support.

DESIGN

Prospective randomized crossover physiologic study.

SETTING

Pediatric six-bed third-level PICU.

PATIENTS

Eighteen children with acute respiratory failure needing noninvasive ventilation were enrolled at PICU admission.

INTERVENTIONS

Enrolled children were allocated to receive two 60-minutes noninvasive flow-triggered pressure support and noninvasive neurally adjusted ventilatory assist trials in a crossover randomized sequence.

MEASUREMENTS AND MAIN RESULTS

Primary endpoint was the asynchrony index. Parameters describing patient-ventilator interaction and gas exchange were also considered as secondary endpoints. Noninvasive neurally adjusted ventilatory assist compared to noninvasive flow-triggered pressure support: 1) reduced asynchrony index (p = 0.001) and the number of asynchronies per minute for each type of asynchrony; 2) it increased the neuroventilatory efficiency index (p = 0.001), suggesting better neuroventilatory coupling; 3) reduced inspiratory and expiratory delay times (p = 0.001) as well as lower peak and mean airway pressure (p = 0.006 and p = 0.038, respectively); 4) lowered oxygenation index (p = 0.043). No adverse event was reported.

CONCLUSIONS

In children with mild early acute respiratory failure, noninvasive neurally adjusted ventilatory assist was feasible and safe. Noninvasive neurally adjusted ventilatory assist compared to noninvasive flow-triggered pressure support improved patient-ventilator interaction.

New modes in non-invasive ventilation

Non-invasive ventilation is useful to treat some forms of respiratory failure. Hence, the number of patients receiving this treatment is steadily increasing. Considerable conceptual and technical progress has been made in the last years by manufacturers concerning this technique. This includes new features committed to improve its effectiveness as well as patient-ventilator interactions. The goal of this review is to deal with latest advances in ventilatory modes and features available for non-invasive ventilation. We present a comprehensive analysis of new modes of ventilator assistance committed to treat respiratory failure (hybrid modes) and central and complex sleep apnea (adaptive servo ventilation), and of new modes of triggering and cycling (neurally adjusted ventilatory assist). Technical aspects, modes of operation and settings of these new features as well as an exhaustive review of published data, their benefits and limits, and the potential place of these devices in clinical practice, are discussed.