Comparison of Physiological Effects of Two High-Flow Tracheal Oxygen Versus T-Piece During Spontaneous Breathing Trials

Official title

Comparison of Physiological Effects of Two Types of High-Flow Tracheal Oxygen Versus T-Piece During Spontaneous Breathing Trials in Mechanically Ventilated Patients

Overview

Spontaneous breathing trials (SBT) are essential for assessing extubation tolerance, yet optimal approaches are debated. High-flow nasal oxygen offers benefits like precise oxygen delivery, flow-related positive end-expiratory pressure generation and improved lung function. While high-flow tracheal oxygen can also be used as an SBT method, it has reduced physiological effects due to bypassing the upper airway with a more open circuit. To enhance this limitation, investigators developed a modified high-flow tracheal oxygen tube with a smaller expiratory end diameter to increase expiratory resistance and airway pressure. This is a prospective randomized crossover study that aims to compare the physiological effects of standard and modified high-flow tracheal oxygen versus T-piece during SBT.

Detailed description

A spontaneous breathing trial (SBT) is a crucial step in the weaning and extubation process for assessing extubation tolerance. However, the optimal approach for conducting SBTs remains a topic of debate.

High-flow nasal oxygen has been shown to provide several physiological benefits, including precise control of the fraction of inspired oxygen, generation of flow-related positive end-expiratory pressure, increased end-expiratory lung volume, improved oxygenation, and enhanced carbon dioxide elimination. High-flow oxygen therapy can also be applied via an artificial airway as high-flow tracheal oxygen. Previous studies have identified this therapy as a potential alternative for SBTs. However, compared to high-flow nasal oxygen, high-flow tracheal oxygen exhibits significantly diminished physiological effects due to the bypassing of the narrow nasopharynx, glottis, and upper airway as well as a more open circuit.

To address this limitation, the investigators have developed a modified high-flow tracheal oxygen tube with a reduced expiratory end tube diameter. This modification aims to create higher expiratory resistance and airway pressure, thereby simulating the physiological effects of HFNC. This study is a prospective randomized crossover physiological study designed to compare the effects of standard and modified high-flow tracheal oxygen versus T-piece during spontaneous breathing trials. Key physiological parameters will be assessed, including airway pressure, end-expiratory lung volume, vital signs, oxygenation, and respiratory workload.

Interventions

• Procedure Modified high flow tracheal oxygen-40L/min
  Modified high-flow tracheal oxygen with a flow rate of 40L/min will be performed.
• Procedure Standard high flow tracheal oxygen-40L/min
  Standard high-flow tracheal oxygen with a flow rate of 40 L/min will be performed.
• Procedure T-piece
  T-piece will be performed.
• Procedure Modified high-flow tracheal oxygen-60L/min
  Modified high-flow tracheal oxygen with a flow rate of 60L/min will be performed.
• Procedure Standard high-flow tracheal oxygen-60 L/min
  Standard high-flow tracheal oxygen with a flow rate of 60 L/min will be performed.

Primary outcome measures

• Mean expiratory airway pressure [Time frame: From enrollment to the end of treatment at 4 hours]
• Positive end-expiratory pressure [Time frame: From enrollment to the end of treatment at 4 hours]
• Change of end-expiatory lung volume [Time frame: From enrollment to the end of treatment at 4 hours]

Secondary outcome measures (8)

• Respiratory rate [Time frame: From enrollment to the end of treatment at 4 hours]
• Tidal volume [Time frame: From enrollment to the end of treatment at 4 hours]
• End-tidal carbon dioxide [Time frame: From enrollment to the end of treatment at 4 hours]
• Pulse oxygen saturation [Time frame: From enrollment to the end of treatment at 4 hours]
• Esophageal pressure-time product [Time frame: From enrollment to the end of treatment at 4 hours]
• Tidal swing of esophageal pressure [Time frame: From enrollment to the end of treatment at 4 hours]
• Respiratory muscle pressure [Time frame: From enrollment to the end of treatment at 4 hours]
• Dynamic transpulmonary pressure [Time frame: From enrollment to the end of treatment at 4 hours]

Eligibility criteria

Inclusion criteria

• Mechanical ventilation for more than 24 hours
• Considered by the physicians for the readiness to wean and ready for spontaneous breathing trials

Exclusion criteria

• Age younger than 18 years old
• Pregnancy
• Hemodynamic instability (mean arterial pressure <60 mmHg, heart rate >140 or <60 bpm)
• Respiratory and oxygenation instability (respiratory rate > 35bpm or oxygen saturation measured by pulse oximetry <90%)
• Neuromuscular diseases or phrenic nerve injury
• Recent trauma or surgery to the trachea, esophagus, neck, chest, or stomach
• Pneumothorax or placement of a chest drainage
• Contraindication to electrical impedance tomography (EIT) (implantable defibrillator)
• Anticipating withdrawal of life support

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Crossover

Masking

Open label

Primary purpose

Treatment

Study locations

China · 1 center

• Beijing Shijitan Hospital — Beijing

Publications

• Xu SS, Zhang RZ, An X, Miao MY, Wang YF, Li HL, Zhou JX. Physiological effects of high-flow oxygen via endotracheal tube versus T-piece strategies during spontaneous breathing trials: a study protocol and statistical analysis for a single-centre randomised crossover study. BMJ Open. 2025 Sep 16;15(9):e105360. doi: 10.1136/bmjopen-2025-105360. PMID 40962338

Identifiers

NCT: NCT06816706 · IIT2024-157-002

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗