Incremental Dead Space Versus Capping Trial Before Tracheostomy Decannulation

Incremental Dead Space Versus Capping Trial to Predict the Post-Decannulation Respiratory Status in Tracheostomized Critically Ill Patients: A Physiological Randomized Crossover Study

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.

Study Overview

• Status: Recruiting
• Conditions: Tracheostomy; Prolonged Mechanical Ventilation; Tracheostomy Decannulation
• Intervention / Treatment: Other: Incremental Instrumental Dead Space; Other: Capping Trial

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 22
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Roque Basoalto Escobar, MSc, PhD; Phone Number: +56984463575; Email: ROQUE.BASOALTO@GMAIL.COM
• Study Contact Backup: Name: Eduardo Kattan Tala, MD, PhD; Email: e.kattan@gmail.com

Study Locations

• Chile
  • Santiago Metropolitan
    • Santiago, Santiago Metropolitan, Chile
      • Recruiting
      • Hospital Clínico UC CHRISTUS, Unidad de Paciente Crítico
      • Contact: Roque Basoalto Escobar, MSc, PhD; Phone Number: +56984463575; Email: ROQUE.BASOALTO@GMAIL.COM

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adult patients (≥18 years) admitted to the ICU.
• Presence of a tracheostomy due to prolonged mechanical ventilation (≥14 days).
• Clinically considered ready for decannulation, according to institutional criteria (e.g., stable gas exchange, minimal secretions, effective cough, and tolerance to spontaneous breathing).
• Ability to maintain spontaneous breathing without mechanical ventilation for more than 48 consecutive hours.
• Able to cooperate and follow basic commands (RASS between -1 and +1).
• Written informed consent obtained from patient.

Exclusion Criteria:

• Neuromuscular disease affecting respiratory muscles (e.g., myasthenia gravis, Guillain-Barre syndrome, amyotrophic lateral sclerosis).
• Hemodynamic instability.
• Severe agitation or delirium precluding cooperation (RASS < -2 or > +2).
• Structural airway abnormalities (e.g., subglottic stenosis, tracheomalacia).
• Pregnancy.
• Contraindications for esophageal balloon catheter insertion (e.g., severe coagulopathy, esophageal varices, and history of esophageal or gastric surgery).
• Refusal to participate by the attending physician.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sequence A: Incremental Dead Space then Capping Trial; 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; 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.; Other: Capping Trial; 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.
Experimental: Sequence B: Capping Trial then Incremental Dead Space; 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; 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.; Other: Capping Trial; 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	During the final 10 minutes of each 45-minute pre-decannulation condition and during the post-decannulation assessment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	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.	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.	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.	Final 10 minutes of each 45-minute study condition and post-decannulation assessment

Collaborators and Investigators

• Sponsor: Pontificia Universidad Catolica de Chile

Publications and helpful links

General Publications

• Nowak A, Martin S, Hohne M, Heller W, Usichenko TI, Klemm E. Tracheal airway pressure in tracheostomy tube capping trials: an experimental study. BMC Pulm Med. 2022 Dec 21;22(1):484. doi: 10.1186/s12890-022-02277-4.
• Devlin CJ, O'Bryan RS, Williams H, Capes KM, McCants T, Schoolcraft E. Improving Outcomes for Patients With Tracheostomy Through Implementation of AARC Clinical Practice Guidelines. Respir Care. 2025 Mar;70(3):243-248. doi: 10.4187/respcare.12080. Epub 2024 Nov 12.
• Basoalto R, Jalil Y, Guzman J, de la Fuente R, Damiani LF, Ibarra-Estrada M, Gorordo-Delsol L, Plotnikow G, Falcon N, Martin N, Munoz-Gama J, Sepulveda M, Kattan E. Tracheostomy decannulation process model: an interprofessional, Latin-American Delphi consensus. Med Intensiva (Engl Ed). 2026 Aug;50(8):502437. doi: 10.1016/j.medine.2026.502437. Epub 2026 Mar 2.

Study record dates

Study Major Dates

• Study Start (Actual): August 17, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: September 2, 2026
• First Submitted That Met QC Criteria: September 2, 2026
• First Posted (Actual): September 9, 2026

Study Record Updates

• Last Update Posted (Actual): September 9, 2026
• Last Update Submitted That Met QC Criteria: September 2, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: critical illness; esophageal pressure; tracheostomy decannulation; capping trial; instrumental dead space
• Additional Relevant MeSH Terms: Pathologic Processes; Disease Attributes; Pathological Conditions, Signs and Symptoms; Critical Illness
• Other Study ID Numbers: 250425028; 11261441 (Other Grant/Funding Number: FONDECYT de Iniciación - Agencia Nacional de Investigación y Desarrollo (ANID), Chile)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: 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.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No