What is this study trying to find out about respiratory effort after major abdominal surgery?

This study aims to understand how patients on mechanical ventilation adjust to different levels of pressure support. Researchers will measure breathing effort using non-invasive tools to identify patterns of under- or over-assistance. The goal is to improve care for patients recovering in the surgical ICU after major abdominal surgery.

Who may be eligible for this respiratory effort clinical trial?

Adults 18 years or older who have had major abdominal surgery and are currently receiving invasive mechanical ventilation with pressure support for more than 48 hours may be eligible. Participants must be clinically stable and able to tolerate adjustments in ventilation. Please review eligibility criteria for more details.

Is there any cost to participate in this respiratory effort clinical trial?

Study-related care, including all procedures and measurements during the trial, is provided at no cost. However, personal expenses such as travel or accommodation may vary and are not guaranteed to be covered.

Actively Recruiting

Phase Not Applicable

Age: 18Years +

All Genders

ID07199881

Observing Breathing Effort at Different Pressure Support Levels in Adults After Major Abdominal Surgery in the ICU

Led by Mahidol University · Updated on 2025-11-18

Participants Needed

Research Sites

52 weeks

Total Duration

AI-Summary

What this Trial Is About

Researchers are evaluating respiratory drive and inspiratory effort in adult patients admitted to the surgical ICU after major abdominal surgery who require mechanical ventilation. This observational study focuses on how patients respond to varying levels of pressure support ventilation PSV using non-invasive bedside measurements. The goal is to better understand patient adaptation to ventilatory support and identify patterns of under- and over-assistance that may affect outcomes. Participants will undergo a standardized stepwise protocol adjusting PSV at different pressure levels, including baseline, -6 cmH2O, -3 cmH2O, 3 cmH2O, 6 cmH2O, and then returning to baseline. Each adjustment is followed by a 2-minute stabilization period and repeated measurements of respiratory drive and inspiratory effort indices, such as airway occlusion pressure at 100 ms P0.1, maximum negative occlusion pressure Pocc, and pressure muscle index PMI. These steps occur while patients remain on PSV for more than 48 hours in the ICU. During the study, researchers will monitor respiratory parameters at each PSV level, assessing how patients adapt. They will also track outcomes like duration of mechanical ventilation, need for reintubation or non-invasive ventilation, ICU length of stay, and hospital discharge disposition. Measurements are taken up to 3 days after enrollment, with follow-up extending through ICU and hospital stays, which may last from one to two months. This detailed monitoring aims to identify optimal PSV titration to improve clinical care.

CONDITIONS

Brief Title

Assessment of Respiratory Drive and Inspiratory Effort Across Pressure Support Levels in Patients After Major Abdominal Surgery

Who Can Participate

Age: 18Years +

All Genders

Eligibility Criteria

You may qualify if you...

Adult patients (≥18 years) admitted to the surgical ICU
Recent major abdominal surgery involving intra-peritoneal operation without primary thoracic involvement
Receiving invasive mechanical ventilation in pressure support ventilation (PSV) mode at enrollment
On invasive mechanical ventilation for more than 48 hours
Clinically stable with no planned extubation within 6 hours, defined by respiratory rate <35 breaths/min, SpO2 ≥90%, heart rate <140 bpm, no visible accessory muscle use, stable hemodynamics without vasopressor escalation, and ability to tolerate short-term PSV adjustments

You will not qualify if you...

Known neuromuscular disease affecting respiratory muscle function
Hemodynamic instability requiring escalation of vasopressor support
Severe hypoxemic respiratory failure needing PEEP >10 cmH2O or FiO2 >60%
Deep sedation (Richmond Agitation-Sedation Scale score < -3) or ongoing neuromuscular blockade
History of chronic obstructive pulmonary disease (COPD) or other obstructive lung disease

Your Study Journey

Screening

Duration - 2 to 4 weeks

Participants are screened for eligibility to participate in the trial.

Diagnostic Evaluation

Duration - Up to 3 days after enrollment

Participants undergo a standardized stepwise pressure support ventilation (PSV) adjustment protocol with repeated measurements of respiratory drive and inspiratory effort indices.

1 protocol session with multiple PSV adjustments and measurements