Clarice Poirier, n/a
Student
Sainte-Justine Hospital, Quebec, Canada
Disclosure information not submitted.
Sally Al-Omar, PhD
Biomedical Engineer, Data Scientist
Sainte Justine Hospital, Quebec, Canada
Disclosure information not submitted.
Michael Sauthier, MD
MD PhD
Sainte Justine Hospital, United States
Disclosure information not submitted.
Guillaume Emeriaud, MD, PhD
Department of Pediatrics, Pediatric Intensive Care Unit
CHU Sainte Justine. Université de Montréal, United States
Disclosure information not submitted.
Title: Factors Associated with Elevated Diaphragmatic Tonic Activity in PICU Patients
Introduction: Tonic diaphragmatic activity (Tonic Edi) represents sustained activation of the diaphragm throughout expiration and reflects patients’ efforts to increase lung recruitment. Its monitoring is a potential tool to titrate ventilation. We recently proposed age-specific definitions of high tonic Edi in the pediatric intensive care unit (PICU) population. Our aims were now to 1) describe the occurrence of episodes of sustained high tonic Edi in the acute phase of ventilation in PICU patients and 2) describe factors independently associated with such episodes.
Methods: Using a high-resolution database, we retrospectively analyzed all patients admitted to Ste-Justine’s Hospital PICU between 2015 and 2020 who had continuous Edi monitoring. Patients supported on ECMO and patients with less than 6 hours of monitoring were excluded. We used our previously described age-specific thresholds for high tonic Edi (3.2mcV in infants < 1 y.o. and 1.9 mcV in children 1-18 y.o.) to identify patients with episodes of sustained ( >45min) elevated tonic Edi in the first 48h hours of monitoring (acute phase). We then used multivariate logistic regression to identify associated factors.
Results: We included 422 patients, with a median age of 3.6 months (1.3-13.1). Sixty three percent of patients on non-invasive ventilation (139/222 patients) and 31% of intubated patients (62/200 patients) presented at least one episode of high tonic Edi. The occurrence of tonic Edi episodes was independently associated with a diagnosis of bronchiolitis (intubated patients: aOR=2.81 (1.13-7.13), p=0,03, NIV patients: aOR=2.68 (1.23-5.90), p=0,01) and a higher respiratory rate (intubated patients: aOR=1.06 (1.00-1.13), p=0,045, NIV: aOR= 1,10 (1.05-1.15), p< 0,001). In patients on NIV, it was also associated with lower estimated PaO2/FiO2 ratio (aOR = 0,99 (0,99-0,99), p=0,03) or SpO2/FiO2 ratio (aOR= 0,99 (0,99-0,99), p=0,004).
Conclusion: Elevated tonic Edi episodes occur frequently in the acute phase, suggesting efforts to increase lung recruitment. It is more frequent in patients with bronchiolitis and is associated with markers of hypoxemia in patients on NIV. Further research is underway to explore if titration of PEEP could be guided by this marker.