An interventional study of Incremental Instrumental Dead Space and Capping Trial in Tracheostomy, Prolonged Mechanical Ventilation and Tracheostomy Decannulation, sponsored by Pontificia Universidad Catolica de Chile. Recruiting at 1 site in Chile. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-09.
Sponsored by Pontificia Universidad Catolica de Chile · Not applicable, Interventional, and Diagnostic
Some critically ill patients need a breathing tube placed directly into the windpipe (tracheostomy) because they require long-term help from a breathing machine. Before this tube can be safely removed (decannulation), medical team need to confirm the patient is ready to breathe on their own through the nose and mouth again. The most common way to check this is a "capping trial," in which the tube is blocked so air must pass through the upper airway, similar to normal breathing. However, because the tube itself remains in place during this test, it narrows the airway and may make breathing harder than it would be if the tube were actually removed. This could cause some patients to fail the test even though they are truly ready for the tube to come out, leading to unnecessary delays.
This study will compare the standard capping trial with a new approach that instead adds extra tubing (dead space) to the breathing circuit, without blocking the airway, to more closely copy the breathing effort patients will experience once the tube is removed. Each participant will undergo both methods, in random order, during a single study day, with breathing effort, muscle activity, and comfort measured during each method and again after the tube is actually removed. The goal is to determine which method more accurately predicts how a patient will actually breathe once the tracheostomy tube is taken out.
Approximately 10-15% of mechanically ventilated intensive care unit (ICU) patients require prolonged mechanical ventilation, and tracheostomy is frequently used to facilitate weaning and respiratory rehabilitation in this population. Tracheostomy decannulation is a key recovery milestone, but there is no standardized method for confirming readiness. The tracheostomy capping trial, in which the tube is occluded to redirect airflow through the upper airway, is the most widely used final assessment prior to decannulation; however, because the tracheostomy tube remains in place, it substantially narrows the airway lumen and may increase airflow resistance up to 16-fold compared to true post-decannulation breathing (per Poiseuille's law). This supraphysiological load may cause capping trial failure in patients who would otherwise tolerate decannulation, particularly those with pre-existing respiratory muscle weakness related to ICU-acquired weakness, which affects up to 80% of patients requiring prolonged mechanical ventilation.
Preliminary physiological data from the investigators' group (unpublished) demonstrated that the esophageal pressure-time product (PTP), a validated marker of the work of breathing, increased by 226% during capping trials compared to baseline, then decreased after actual decannulation to levels close to baseline, suggesting the capping trial substantially overestimates the respiratory burden that patients will face after tube removal.
This study proposes an alternative physiological assessment using incremental instrumental dead space, which reproduces the anatomical dead space increase that occurs after decannulation without imposing the artificial airway resistance created by the tracheostomy tube during capping. In a randomized crossover design, each participant will undergo both the capping trial and the incremental dead space strategy in random order, followed by assessment after actual decannulation, allowing within-participant comparison of which method better predicts the true post-decannulation respiratory status.
1,780 studies on the registry are indexed under Critical Illness; 442 are open to participants now.
This study's planned enrollment of 22 is below the median of 90 across 926 interventional studies indexed under Critical Illness.
Browse Critical Illness studies →Pontificia Universidad Catolica de Chile is the lead sponsor of 224 studies on the registry; 59 are open to participants now.
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Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
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Participants first undergo the incremental instrumental dead space trial for 45 minutes. After a 20-minute washout breathing spontaneously through an open T-piece connected to the tracheostomy, participants undergo the capping trial for 45 minutes. Following completion of both conditions and confirmation of decannulation by the clinical team, participants undergo post-decannulation assessment.
Other: Incremental Instrumental Dead Space · Other: Capping Trial
Participants first undergo the capping trial for 45 minutes. After a 20-minute washout breathing spontaneously through an open T-piece connected to the tracheostomy, participants undergo the incremental instrumental dead space trial for 45 minutes. Following completion of both conditions and confirmation of decannulation by the clinical team, participants undergo post-decannulation assessment.
Other: Incremental Instrumental Dead Space · Other: Capping Trial
Instrumental dead space applied through a modular low-resistance circuit connected to the tracheostomy for 45 minutes, intended to reproduce the respiratory demand associated with restoration of the upper airway after decannulation.
The tracheostomy cuff is deflated and the tube is completely occluded with a standard cap, requiring the participant to breathe through the upper airway for 45 minutes unless predefined intolerance or safety criteria require earlier discontinuation.
Within-Participant Absolute Error in Pressure-Time Product Post-Decannulation Breathing
Respiratory effort will be quantified using the esophageal pressure-time product per breath (PTP), calculated from the esophageal pressure signal. For each pre-decannulation strategy, predictive accuracy will be quantified as the absolute within-participant difference between PTP measured during that strategy and PTP measured during post-decannulation spontaneous breathing. The primary comparison will assess whether the absolute error is lower during incremental instrumental dead space than during the capping trial.
Time frame: During the final 10 minutes of each 45-minute pre-decannulation condition and during the post-decannulation assessment
Accessory Respiratory Muscle Surface Electromyography Activity
Surface electromyography will quantify respiratory muscle recruitment in the sternocleidomastoid, intercostal/parasternal, and abdominal muscles. Signal amplitude and prespecified frequency-domain characteristics will be analyzed offline according to the final signal-processing plan.
Time frame: Final 10 minutes of each 45-minute study condition and post-decannulation assessment
Perceived Dyspnea / Respiratory Discomfort
Participant-reported respiratory discomfort assessed using the modified Borg scale from 0 to 10.
Time frame: Beginning and end of each 45-minute study condition and when clinically indicated
Esophageal Pressure Swing (ΔPes)
Mean inspiratory esophageal pressure swing measured from the esophageal pressure signal as an index of inspiratory effort.
Time frame: Final 10 minutes of each 45-minute study condition and post-decannulation assessment
Pressure-Time Product per Minute (PTPmin)
Pressure-time product per minute, calculated from the esophageal pressure signal by integrating the per-breath pressure-time product over one minute of recording.
Time frame: Final 10 minutes of each 45-minute study condition and post-decannulation assessment
Plan to share: No — Individual participant data will not be shared beyond the study team, given the small single-center sample size and the identifiability risk associated with detailed physiological and clinical data from a small, specific patient population.
Started Aug 2026 (actual). Primary completion is estimated for Dec 2028, 28 months after the start.
Of 399 non-industry interventional studies with no phase under Critical Illness, half reached primary completion within 21 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 40. This study's planned 28 months is above that.
Counting every sponsor, half of 403 studies reached it within 21 months; a quarter within 12 and three quarters within 40.
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