The Hering-Breuer Reflex in Bilateral Lung Transplant Patients

NCT07280611 | Recruiting

• 1 other identifier: ID 5483
• Study Type: interventional
• Target: 22
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Hering-Breuer Reflex

Keywords

Hering-Breuer reflex; Bilateral Lung Transplant

Outcome Measures

Primary Outcomes (1)

• THBR/TSPONT ratio

  Comparison of the ratio between the diaphragm electrical activation time after a high-volume breath aimed at eliciting the HBR (THBR) and a spontaneous breath (TSPONT), i.e., the THBR/TSPONT ratio, between patients who underwent bilateral lung transplantation and those who underwent non-thoracic surgery.

  At the enrollment

Secondary Outcomes (1)

• The variation of the THBR/TSPONT ratio as a function of PEEP

  At the enrollment

Study Arms (2)

Bilateral Lung Transplant patients

EXPERIMENTAL

This group include patients admitted to the Intensive Care Unit for post-operative care following bilateral lung transplantation during the weaning phase from mechanical ventilation. The following patients will be excluded: minors, those undergoing retransplantation, single-lung transplantation or urgent lung transplantation; patients with respiratory system compliance \< 30 mL/cmH2O; haemodynamically unstable patients and those at increased risk of bleeding due to nasogastric tube placement.

Device: Nasogastric tube placement and elicitation of Hering-Breuer reflex

Non-thoracic surgery patients

ACTIVE COMPARATOR

This group include patients admitted to the Intensive Care Unit for post-operative care or monitoring after non-thoracic surgery. The following patients will be excluded: minors, those who had undergone previous lung transplant or thoracic surgery; patients with respiratory system compliance \< 30 mL/cmH2O; haemodynamically unstable patients; those at increased risk of bleeding due to nasogastric tube placement and patients with contraindications to nasogastric tube placement.

Device: Nasogastric tube placement and elicitation of Hering-Breuer reflex

Interventions

Nasogastric tube placement and elicitation of Hering-Breuer reflex DEVICE

Enrolled patients will have a nasogastric tube placed, through which diaphragmatic electrical activity will be measured. Patients will be ventilated in pressure support mode with an expansion breath delivered at a maximum pressure of approximately 30 cmH2O in order to elicit the Hering-Breuer Reflex. Diaphragmatic electrical activity, timing, volumes and pressures will then be analyzed before and after the expansion breath over a 10 minute period, testing two levels of PEEP (8 and 12 cmH2O).

Bilateral Lung Transplant patients; Non-thoracic surgery patients

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age \>18 years;
• Both sexes;
• For group 1: patients admitted to the Intensive Care Unit after undergoing bilateral lung transplantation, during respiratory weaning;
• For group 2: patients admitted to the Intensive Care Unit for support or monitoring after non-thoracic surgery, who will arrive intubated.

You may not qualify if:

• For group 1, patients meeting at least one of the following criteria will be excluded:
• Re-transplantation or single-lung transplantation;
• Urgent lung transplantation;
• Post-transplant respiratory system compliance \< 30 mL/cmH₂O;
• Hemodynamic instability (defined as the presence of one or more of the following: plasma lactate \> 4 mmol/L, need for vasoactive support with norepinephrine and/or epinephrine at a dose \> 0.05 mcg/kg/min, systolic arterial pressure \< 80 mmHg);
• Increased risk of bleeding related to the placement of a nasogastric tube due to coagulopathy or severe thrombocytopenia (INR \> 2 and platelets \< 70,000);
• Pregnancy
• For group 2, patients presenting with one or more of the following criteria will be excluded:
• Postoperative respiratory system compliance \< 30 mL/cmH₂O;
• Hemodynamic instability (defined as the presence of one or more of the following: plasma lactate \> 4 mmol/L, need for vasoactive support with norepinephrine and/or epinephrine at a dose \> 0.05 mcg/kg/min, systolic arterial pressure \< 80 mmHg);
• Contraindications to nasogastric tube placement (gastroesophageal surgery within the last 3 months, gastroesophageal bleeding in the previous 30 days, esophageal varices, facial trauma);
• Increased risk of bleeding related to the placement of a nasogastric tube due to coagulopathy or severe thrombocytopenia (INR \> 2 and platelets \< 70,000);
• History of lung transplantation or major thoracic surgery;
• Pregnancy.

Sponsors & Collaborators

• Policlinico Hospital: lead

Study Sites (1)

Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico

Milan, Michigan, 20122, Italy

RECRUITING

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Head of department of Anestesia and Intensive care unit

Model Details: The study will be conducted on two groups of subjects: * Patients admitted to the Intensive Care Unit for post-operative care following bilateral lung transplantation (Group 1); * Patients admitted to the Intensive Care Unit for post-operative care or monitoring after non-thoracic surgery (Group 2 - control group)

Study Record Dates

• First Submitted: December 1, 2025
• First Posted: December 12, 2025
• Study Start: October 7, 2025
• Primary Completion: January 1, 2026
• Study Completion (Estimated): June 1, 2026
• Last Updated: December 12, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will share

Locations

IT (1)