The Hering-Breuer Reflex in Bilateral Lung Transplant Patients
The goal of this clinical trial (non-pharmacologic, single-center) is to determine whether the Hering-Breuer inflation reflex is preserved-and how it is modulated by end-expiratory pressure-in adult intensive-care patients who have undergone bilateral lung transplantation.
The study will enroll men and women ≥ 18 years admitted to the ICU during the early weaning phase and will include a comparison group of intubated ICU patients after major non-thoracic surgery.
The main questions it aims to answer are:
* Is the Hering-Breuer reflex (measured as the ratio THBR/TSPONT) absent or attenuated in double-lung-transplant recipients?
* Does changing the level of positive end-expiratory pressure (PEEP 8 vs 12 cmH₂O) influence the reflex?
Comparison group: Researchers will compare the transplant arm (post-bilateral lung transplantation) with the control arm (post-operative, non-thoracic surgery patients) to see whether loss or blunting of the reflex-and its response to PEEP-differs between the two cohorts.
Participants will:
* Have a nasogastric catheter with embedded electrodes positioned to record the electrical activity of the diaphragm (EAdi).
* Be ventilated in pressure-support mode at two preset PEEP levels (8 cmH₂O and 12 cmH₂O) during the weaning phase.
* Receive one standardized high-volume insufflation at \~30 cmH₂O in each PEEP condition to elicit the reflex, while EAdi, airway pressures, inspiratory/expiratory times, and tidal volumes are recorded for 10 minutes per level.
Gender: All
Ages: 18 Years - Any
