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Tonic diaphragmatic activity in critically ill children with and without ventilatory support
Author(s) -
Larouche Alexandrine,
Massicotte Erika,
Constantin Gabrielle,
DucharmeCrevier Laurence,
Essouri Sandrine,
Sinderby Christer,
Beck Jennifer,
Emeriaud Guillaume
Publication year - 2015
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.23182
Subject(s) - medicine , tonic (physiology) , interquartile range , mechanical ventilation , anesthesia , expiration , cardiology , respiratory system
Summary Background Infants have to actively maintain their end expiratory lung volume (EELV). In mechanically ventilated infants, the diaphragm stays activated until the end of expiration (tonic activity), contributing to EELV maintenance. It is unclear whether tonic activity compensates for the lack of laryngeal braking due to intubation or if it is normally present. Objective To determine if tonic diaphragm activity remains after extubation in infants, and if it can be observed in older children. Methods Prospective observational study of pediatric patients ventilated for >24 hr. Diaphragm electrical activity (EAdi) was recorded using a specific nasogastric catheter during four periods: (i) the acute phase, (ii) pre‐extubation, (iii) post‐extubation, and (iv) at PICU discharge. Tonic EAdi was defined as the EAdi in the last quartile of expiration. Results Fifty‐five patients, median age 10 months (Interquartile range: 1–48) were studied. In infants (<1 year, n = 28), tonic EAdi was always present, and represented 33% (22–43) of inspiratory EAdi at PICU discharge. No significant change was observed between pre‐ and post‐extubation periods. In older patients (n = 27), tonic activity was negligible as a whole, but 10 patients exhibited significant tonic EAdi at one time‐point during PICU stay. Bronchiolitis was the only independent factor associated with tonic EAdi. Conclusions In infants, tonic EAdi remains involved in ventilatory control after extubation and restoration of laryngeal braking. Tonic EAdi may play a pathophysiological role in bronchiolitis and it can be reactivated in older patients. The interest of tonic EAdi as a tool to titrate mechanical ventilation warrants further evaluation. Pediatr Pulmonol. 2015; 50:1304–1312. © 2015 Wiley Periodicals, Inc.