Varela Javier, Aranis Nadine, Varas Francisca, Vallejos Martina, Bruhn Alejandro
Department of Pediatrics, Pediatric Intensive Care Unit, Clínica Alemana de Santiago, Santiago, Chile.
Department of Pediatrics, Pediatric Intensive Care Unit, Hospital Padre Hurtado, Santiago, Chile.
Pediatr Crit Care Med. 2025 Sep 1;26(9):e1096-e1104. doi: 10.1097/PCC.0000000000003790. Epub 2025 Jul 1.
This study aimed to explore whether airway closure can be detected in patients with severe acute bronchiolitis on invasive mechanical ventilation.
Single-center prospective physiologic study carried out in 2023-2024.
PICU in a tertiary-care general hospital.
Infants with acute bronchiolitis undergoing invasive mechanical ventilation.
Under deep sedation and neuromuscular blockade, the mechanical ventilator, in a volume-controlled mode, was transiently set with a respiratory rate of five breaths/min, a tidal volume of 6 mL/kg of ideal body weight, positive end-expiratory pressure 0 cm H 2 O, a flow rate of 2 L/min, an inspiratory-expiratory ratio of 1:1, and a F io2 of 1.0. After recording three breath cycles, the patient was returned to baseline ventilatory settings.
We identified the presence of airway closure through the low-flow pressure-volume curve obtained from a pneumotachometer with a flow sensor placed at the Y-piece and simultaneously from the pressure-impedance curve and ventilation maps acquired using electrical impedance tomography. We included 12 patients, and airway closure was detected in seven of them. The median (interquartile range [IQR]) airway opening pressure was 14 cm H 2 O (IQR, 11-17 cm H 2 O). Patients with airway closure exhibited high levels of driving pressure, with a median of 16 cm H 2 O (IQR, 11-17 cm H 2 O), and low levels of respiratory system compliance, with a median of 0.41 mL/cm H 2 O/kg (IQR, 0.38-0.59 mL/cm H 2 O/kg). When these parameters were corrected for airway opening pressure, there was a significant decrease in driving pressure to 9 cm H 2 O (IQR, 8-12 cm H 2 O; p = 0.018) and a significant increase in respiratory system compliance to 0.70 mL/cm H 2 O/kg (IQR, 0.53-0.81 mL/cm H 2 O/kg; p = 0.018).
Airway closure requiring high opening pressures can be detected in ventilated infants with acute bronchiolitis, and this phenomenon may impact respiratory mechanics.
