Guillaume Emeriaud

Objectives And Hypothesis: Tonic diaphragmatic activity is common during non‐invasive ventilation (NIV), suggesting efforts to increase end‐expiratory lung volume. We assessed the feasibility and physiological impact of NeuroPAP, a novel NIV mode continuously adjusting the delivered positive pressure proportionally to diaphragm electric activity (Edi) during both inspiration and expiration, in infants with respiratory failure. We hypothesized NeuroPAP would enable dynamic control of end‐expiratory pressures (PEEP). Methodology: This prospective crossover study enrolled premature neonates (25–34 weeks) and infants with bronchiolitis supported by NIV‐NAVA. Subjects underwent three ventilation phases: NIV‐NAVA, NeuroPAP, and repeat NIV‐NAVA. Ventilation pressures, Edi, cardio‐respiratory events, neural breathing patterns, and systemic and cerebral oxygenation were assessed. Results: A total of 15 infants with bronchiolitis and 8 premature neonates were included. The overall median PEEP was unchanged between modes, but PEEP was actively adjusted, with increased breath‐to‐breath variability of PEEP in NeuroPAP ( p < 0.001). Compared to pre‐study settings, individual PEEP increased in NeuroPAP in 7, decreased in 9, and was unchanged in 7 patients. In NeuroPAP, the breathing pattern was phasic 74% of the time and tonic 16% of the time, compared to 61% ( p = 0.31) and 23% ( p = 0.36) in NIV‐NAVA. Respiratory rate was lower in NeuroPAP in the neonates ( p = 0.006). The estimated PaO ₂ /FiO ₂ ratio was higher in the post‐NeuroPAP NIV‐NAVA period in the bronchiolitis group ( p = 0.006). Edi, heart rate, cerebral NIRS, or cardio‐respiratory events were unchanged. Conclusion: In infants with respiratory failure, NeuroPAP allowed dynamic control and personalization of PEEP. The clinical impact of this warrants further evaluation.

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.

OBJECTIVES: The worldwide practice and impact of noninvasive ventilation (NIV) in pediatric acute respiratory distress syndrome (PARDS) is unknown. We sought to describe NIV use and associated clinical outcomes in PARDS. DESIGN: Planned ancillary study to the 2016/2017 prospective Pediatric Acute Respiratory Distress Syndrome Incidence and Epidemiology study. SETTING: One hundred five international PICUs. PATIENTS: Patients with newly diagnosed PARDS admitted during 10 study weeks. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Children were categorized by their respiratory support at PARDS diagnosis into NIV or invasive mechanical ventilation (IMV) groups. Of 708 subjects with PARDS, 160 patients (23%) received NIV at PARDS diagnosis (NIV group). NIV failure rate (defined as tracheal intubation or death) was 84 of 160 patients (53%). Higher nonrespiratory pediatric logistic organ dysfunction (PELOD-2) score, Pao ₂/Fio ₂ was less than 100 at PARDS diagnosis, immunosuppression, and male sex were independently associated with NIV failure. NIV failure was 100% among patients with nonrespiratory PELOD-2 score greater than 2, Pao ₂/Fio ₂ less than 100, and immunosuppression all present. Among patients with Pao ₂/Fio ₂ greater than 100, children in the NIV group had shorter total duration of NIV and IMV, than the IMV at initial diagnosis group. We failed to identify associations between NIV use and PICU survival in a multivariable Cox regression analysis (hazard ratio 1.04 [95% CI, 0.61–1.80]) or mortality in a propensity score matched analysis (p = 0.369). CONCLUSIONS: Use of NIV at PARDS diagnosis was associated with shorter exposure to IMV in children with mild to moderate hypoxemia. Even though risk of NIV failure was high in some children, we failed to identify greater hazard of mortality in these patients.

OBJECTIVES: Tonic diaphragmatic activity (tonic Edi, i.e., sustained diaphragm activation throughout expiration) reflects diaphragmatic effort to defend end-expiratory lung volumes. Detection of such elevated tonic Edi may be useful in identifying patients who need increased positive end-expiratory pressure. We aimed to: 1) identify age-specific definitions for elevated tonic Edi in ventilated PICU patients and 2) describe the prevalence and factors associated with sustained episodes of high tonic Edi. DESIGN: Retrospective study using a high-resolution database. SETTING: Single-center tertiary PICU. PATIENTS: Four hundred thirty-one children admitted between 2015 and 2020 with continuous Edi monitoring. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We characterized our definition of tonic Edi using data from the recovery phase of respiratory illness (i.e., final 3 hr of Edi monitoring, excluding patients with significant persistent disease or with diaphragm pathology). High tonic Edi was defined as population data exceeding the 97.5th percentile, which for infants younger than 1 year was greater than 3.2 μV and for older children as greater than 1.9 μV. These thresholds were then used to identify patients with episodes of sustained elevated tonic Edi in the first 48 hours of ventilation (acute phase). Overall, 62 of 200 (31%) of intubated patients and 138 of 222 (62%) of patients on noninvasive ventilation (NIV) had at least one episode of high tonic Edi. These episodes were independently associated with the diagnosis of bronchiolitis (intubated patients: adjusted odds [aOR], 2.79 [95% CI, 1.12–7.11]); NIV patients: aOR, 2.71 [1.24–6.0]). There was also an association with tachypnea and, in NIV patients, more severe hypoxemia. CONCLUSIONS: Our proposed definition of elevated tonic Edi quantifies abnormal diaphragmatic activity during expiration. Such a definition may help clinicians to identify those patients using abnormal effort to defend end-expiratory lung volume. In our experience, high tonic Edi episodes are frequent, especially during NIV and in patients with bronchiolitis.

Rationale: Pediatric-specific ventilator liberation guidelines are lacking despite the many studies exploring elements of extubation readiness testing. The lack of clinical practice guidelines has led to significant and unnecessary variation in methods used to assess pediatric patients’ readiness for extubation. Methods: Twenty-six international experts comprised a multiprofessional panel to establish pediatrics-specific ventilator liberation clinical practice guidelines, focusing on acutely hospitalized children receiving invasive mechanical ventilation for more than 24 hours. Eleven key questions were identified and first prioritized using the Modified Convergence of Opinion on Recommendations and Evidence. A systematic review was conducted for questions that did not meet an a priori threshold of ⩾80% agreement, with Grading of Recommendations, Assessment, Development, and Evaluation methodologies applied to develop the guidelines. The panel evaluated the evidence and drafted and voted on the recommendations. Measurements and Main Results: Three questions related to systematic screening using an extubation readiness testing bundle and a spontaneous breathing trial as part of the bundle met Modified Convergence of Opinion on Recommendations criteria of ⩾80% agreement. For the remaining eight questions, five systematic reviews yielded 12 recommendations related to the methods and duration of spontaneous breathing trials, measures of respiratory muscle strength, assessment of risk of postextubation upper airway obstruction and its prevention, use of postextubation noninvasive respiratory support, and sedation. Most recommendations were conditional and based on low to very low certainty of evidence. Conclusions: This clinical practice guideline provides a conceptual framework with evidence-based recommendations for best practices related to pediatric ventilator liberation.