Inspiratory EffortNCT07199881
Assessment of Respiratory Drive and Inspiratory Effort Across Pressure Support Levels in Patients After Major Abdominal Surgery
A study testing Stepwise PSV adjustment protocol in people with Inspiratory Effort and Mechanical Ventilation, run by Mahidol University at 1 site in Thailand.
Trial summary
This physiological observational study will assess respiratory drive and inspiratory effort across varying levels of pressure support ventilation (PSV) in adult surgical ICU (SICU) patients after major abdominal surgery. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Inspiratory Effort, Mechanical Ventilation, Major Abdominal Surgeries
- What is being tested?
- Stepwise PSV adjustment protocol
- Type of treatment
- Surgery or procedure
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 40 participants
- Where
- 1 siteThailand
- Study dates
- 31 Oct 2025to 30 Sep 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Adult patients (≥18 years) admitted to the surgical ICU
- Recent major abdominal surgery (intra-peritoneal operation without primary thoracic involvement, including luminal resection and/or resection of a gastrointestinal solid organ) requiring postoperative ICU care
- Receiving invasive mechanical ventilation in pressure support ventilation (PSV) mode at the time of enrollment
- Duration of invasive mechanical ventilation >48 hours
- Clinically stable, with no plan for extubation within 6 hours of study enrollment, defined by all of the following: Respiratory rate <35 breaths/min, SpO₂ ≥90%, Heart rate <140 bpm, No visible accessory muscle use, Hemodynamically stable without escalation of vasopressor support during the past hour, Able to tolerate short-term adjustments in PSV level as per protocol
Who cannot join
- Known neuromuscular disease affecting respiratory muscle function
- Hemodynamic instability requiring escalation of vasopressor support
- Severe hypoxemic respiratory failure requiring Positive End-Expiratory Pressure (PEEP) >10 cmH₂O or FiO₂ >60%
- Deep sedation (Richmond Agitation-Sedation Scale [RASS] score < -3) or ongoing neuromuscular blockade
- History of chronic obstructive pulmonary disease (COPD) or other obstructive lung disease
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Thailand1 site, 1 recruiting
- Recruiting
Faculty of Medicine, Siriraj Hospital, Mahidol University
Bangkok, Bangkoknoi, 10700
Nuanprae Kitisin, MD, +66896767706, nuanprae.kit@mahidol.ac.th
About this study
This physiological observational study will assess respiratory drive and inspiratory effort across varying levels of pressure support ventilation (PSV) in adult surgical ICU (SICU) patients after major abdominal surgery. By using non-invasive bedside indices (airway occlusion pressure at 100 ms after the onset of inspiration [P0.1], maximum negative occlusion pressure [Pocc], and pressure muscle index [PMI]), we aim to quantify how patients adapt to changes in ventilatory support and determine patterns of under- and over-assistance. Findings may inform optimal titration of PSV to reduce complications and improve clinical outcomes.
- Being tested
- Stepwise PSV adjustment protocol
- Keywords
- Pressure support ventilation, respiratory drive, inspiratory effort, mechanical ventilation, Major Abdominal Surgery
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Stepwise PSV adjustment protocolProcedure or surgery
Patients will undergo standardized stepwise PSV changes (baseline, ±3 cmH₂O, ±6 cmH₂O, return to baseline), with 2-minute stabilization and repeated measurements of ventilatory parameters.
| Study group | Role | What they receive |
|---|---|---|
| Single Cohort (Postoperative SICU patients on PSV >48h) | Experimental | Adult patients admitted to the surgical ICU after major abdominal surgery who remain on pressure support ventilation (PSV) for more than 48 hours. Each participant will undergo a standardized stepwise protocol of PSV adjustment (baseline, -6 cmH₂O, -3 cmH₂O, +3 cmH₂O, +6 cmH₂O, return to baseline). At each step, a 2-minute stabilization is followed by repeated measurements of respiratory drive and inspiratory effort indices (P0.1, Pocc, PMI) and ventilatory parameters. Receives: Procedure: Stepwise PSV adjustment protocol |
What is being measured
The primary outcome is the main question the study is designed to answer.
Respiratory drive and inspiratory effort across pressure support levels
Respiratory drive and inspiratory effort will be assessed using airway occlusion pressure at 0.1 seconds (P0.1), maximum negative inspiratory occlusion pressure (Pocc), and the pressure muscle index (PMI). These indices are measured non-invasively via ventilator maneuvers during standardized stepwise adjustments of pressure support ventilation (baseline, ±3 cmH₂O, ±6 cmH₂O, return to baseline). The mean of three repeated measurements at each step will be analyzed.
Measured: Baseline and during protocol sessions, up to 3 days after enrollment
Secondary outcomes (5)
Incidence of ventilatory response patterns during PSV
Ventilatory response patterns will be categorized as quasi-passive or active based on physiological criteria derived from changes in tidal volume, plateau pressure, and PMI during stepwise PSV adjustments. Patterns will be determined from individual response trends.
Measured: Baseline and during protocol sessions, up to 3 days after enrollment
Duration of mechanical ventilation after protocol
Time from completion of the PSV protocol until successful extubation, measured in hours. Reintubation within 48 hours will be recorded separately.
Measured: Within 48 hours after extubation
Reintubation or non-invasive ventilation use
Proportion of patients requiring reintubation or initiation of non-invasive ventilation within 48 hours after extubation following study participation.
Measured: 48 hours after extubation
ICU length of stay
Total number of days from ICU admission to ICU discharge.
Measured: Through ICU stay, an average of 7-21 days
Hospital discharge disposition
Patient's status at hospital discharge (alive vs. deceased; home vs. rehabilitation vs. long-term care).
Measured: Through hospital stay, an average of 14-60 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted30 Sep 2025
- Study start31 Oct 2025
- Primary completion30 Sep 2026 (estimated)
- Study completion30 Sep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (6)Papers the sponsor has linked to this study.
- Other trials for Inspiratory EffortStudies of the same condition, open and under way.
- More trials run by Mahidol UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 40 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mahidol University
- Sponsor type
- University, hospital or other
- Collaborators
- Siriraj Hospital
- Responsible party
- Sponsor
- Investigators
- Nuanprae Kitisin, Principal investigator, Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07199881
- Sponsor's protocol ID
- PSV-SICU_SIRIRAJ
- Status last verified
- Nov 2025
- First submitted
- 10 Sep 2025
- Last updated
- 18 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: This is a single-center physiological observational study with a modest sample size. No plan to share individual participant data outside the study team. Summary data will be available in publications
Publications
He Q, Lai Z, Peng S, Lin S, Mo G, Zhao X, Wang Z. Postoperative pulmonary complications after major abdominal surgery in elderly patients and its association with patient-controlled analgesia. BMC Geriatr. 2024 Sep 10;24(1):751. doi: 10.1186/s12877-024-05337-y.
PubMed 39256677Miskovic A, Lumb AB. Postoperative pulmonary complications. Br J Anaesth. 2017 Mar 1;118(3):317-334. doi: 10.1093/bja/aex002.
PubMed 28186222Courtney A, Clymo J, Dorudi Y, Moonesinghe SR, Dorudi S. Scoping review: The terminology used to describe major abdominal surgical procedures. World J Surg. 2024 Mar;48(3):574-584. doi: 10.1002/wjs.12084. Epub 2024 Feb 11.
PubMed 38342951Docci M, Foti G, Brochard L, Bellani G. Pressure support, patient effort and tidal volume: a conceptual model for a non linear interaction. Crit Care. 2024 Nov 6;28(1):358. doi: 10.1186/s13054-024-05144-2.
PubMed 39506755Al-Bassam W, Parikh T, Neto AS, Idrees Y, Kubicki MA, Hodgson CL, Subramaniam A, Reddy MP, Gullapalli N, Michel C, Matthewman MC, Naughton J, Pereira J, Shehabi Y, Bellomo R. Pressure support ventilation in intensive care patients receiving prolonged invasive ventilation. Crit Care Resusc. 2023 Oct 18;23(4):394-402. doi: 10.51893/2021.4.OA4. eCollection 2021 Dec 6.
PubMed 38046681van Oosten JP, Akoumianaki E, Jonkman AH. Monitoring respiratory muscles effort during mechanical ventilation. Curr Opin Crit Care. 2025 Feb 1;31(1):12-20. doi: 10.1097/MCC.0000000000001229. Epub 2024 Nov 14.
PubMed 39560150
Study at a glance
From the registry record, last updated by the sponsor on 18 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Assessment of Respiratory Drive and Inspiratory Effort Across Pressure Support Levels in Patients After Major Abdominal Surgery
- ClinicalTrials.gov ID
- NCT07199881
- Acronym / sponsor ID
- PSV-SICU_SIRIRAJ
- Keywords
- Pressure support ventilation, respiratory drive, inspiratory effort, mechanical ventilation, Major Abdominal Surgery
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 40 participants (estimated)
- Lead sponsor
- Mahidol UniversityUniversity, hospital or other
- Collaborators
- Siriraj Hospital
- Study start
- 31 Oct 2025 (actual)
- Primary completion
- 30 Sep 2026 (estimated)
- Study completion
- 30 Sep 2027 (estimated)
- First posted
- 30 Sep 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This physiological observational study will assess respiratory drive and inspiratory effort across varying levels of pressure support ventilation (PSV) in adult surgical ICU (SICU) patients after major abdominal surgery. By using non-invasive bedside indices (airway occlusion pressure at 100 ms after the onset of inspiration [P0.1], maximum negative occlusion pressure [Pocc], and pressure muscle index [PMI]), we aim to quantify how patients adapt to changes in ventilatory support and determine patterns of under- and over-assistance. Findings may inform optimal titration of PSV to reduce complications and improve clinical outcomes.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Single Cohort (Postoperative SICU patients on PSV >48h) | Experimental | Procedure: Stepwise PSV adjustment protocolAdult patients admitted to the surgical ICU after major abdominal surgery who remain on pressure support ventilation (PSV) for more than 48 hours. Each participant will undergo a standardized stepwise protocol of PSV adjustment (baseline, -6 cmH₂O, -3 cmH₂O, +3 cmH₂O, +6 cmH₂O, return to baseline). At each step, a 2-minute stabilization is followed by repeated measurements of respiratory drive and inspiratory effort indices (P0.1, Pocc, PMI) and ventilatory parameters. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Adult patients (≥18 years) admitted to the surgical ICU
- Recent major abdominal surgery (intra-peritoneal operation without primary thoracic involvement, including luminal resection and/or resection of a gastrointestinal solid organ) requiring postoperative ICU care
- Receiving invasive mechanical ventilation in pressure support ventilation (PSV) mode at the time of enrollment
- Duration of invasive mechanical ventilation >48 hours
- Clinically stable, with no plan for extubation within 6 hours of study enrollment, defined by all of the following: Respiratory rate <35 breaths/min, SpO₂ ≥90%, Heart rate <140 bpm, No visible accessory muscle use, Hemodynamically stable without escalation of vasopressor support during the past hour, Able to tolerate short-term adjustments in PSV level as per protocol
Key exclusion criteria (5 listed)
- Known neuromuscular disease affecting respiratory muscle function
- Hemodynamic instability requiring escalation of vasopressor support
- Severe hypoxemic respiratory failure requiring Positive End-Expiratory Pressure (PEEP) >10 cmH₂O or FiO₂ >60%
- Deep sedation (Richmond Agitation-Sedation Scale [RASS] score < -3) or ongoing neuromuscular blockade
- History of chronic obstructive pulmonary disease (COPD) or other obstructive lung disease
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Stepwise PSV adjustment protocolPatients will undergo standardized stepwise PSV changes (baseline, ±3 cmH₂O, ±6 cmH₂O, return to baseline), with 2-minute stabilization and repeated measurements of ventilatory parameters. | Procedure or surgery | Single Cohort (Postoperative SICU patients on PSV >48h) |
Primary outcome
Respiratory drive and inspiratory effort across pressure support levels
Time frame: Baseline and during protocol sessions, up to 3 days after enrollment
Respiratory drive and inspiratory effort will be assessed using airway occlusion pressure at 0.1 seconds (P0.1), maximum negative inspiratory occlusion pressure (Pocc), and the pressure muscle index (PMI). These indices are measured non-invasively via ventilator maneuvers during standardized stepwise adjustments of pressure support ventilation (baseline, ±3 cmH₂O, ±6 cmH₂O, return to baseline). The mean of three repeated measurements at each step will be analyzed.
5 secondary outcomes
Incidence of ventilatory response patterns during PSV
Time frame: Baseline and during protocol sessions, up to 3 days after enrollment
Duration of mechanical ventilation after protocol
Time frame: Within 48 hours after extubation
Reintubation or non-invasive ventilation use
Time frame: 48 hours after extubation
ICU length of stay
Time frame: Through ICU stay, an average of 7-21 days
Hospital discharge disposition
Time frame: Through hospital stay, an average of 14-60 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Nov 2025.
- Results publication: PubMed 39256677He Q, Lai Z, Peng S, Lin S, Mo G, Zhao X, Wang Z. Postoperative pulmonary complications after major abdominal surgery in elderly patients and its association with patient-controlled analgesia. BMC Geriatr. 2024 Sep 10;24(1):751. doi: 10.1186/s12877-024-05337-y.
- Results publication: PubMed 28186222Miskovic A, Lumb AB. Postoperative pulmonary complications. Br J Anaesth. 2017 Mar 1;118(3):317-334. doi: 10.1093/bja/aex002.
- Results publication: PubMed 38342951Courtney A, Clymo J, Dorudi Y, Moonesinghe SR, Dorudi S. Scoping review: The terminology used to describe major abdominal surgical procedures. World J Surg. 2024 Mar;48(3):574-584. doi: 10.1002/wjs.12084. Epub 2024 Feb 11.
- Results publication: PubMed 39506755Docci M, Foti G, Brochard L, Bellani G. Pressure support, patient effort and tidal volume: a conceptual model for a non linear interaction. Crit Care. 2024 Nov 6;28(1):358. doi: 10.1186/s13054-024-05144-2.
- Results publication: PubMed 38046681Al-Bassam W, Parikh T, Neto AS, Idrees Y, Kubicki MA, Hodgson CL, Subramaniam A, Reddy MP, Gullapalli N, Michel C, Matthewman MC, Naughton J, Pereira J, Shehabi Y, Bellomo R. Pressure support ventilation in intensive care patients receiving prolonged invasive ventilation. Crit Care Resusc. 2023 Oct 18;23(4):394-402. doi: 10.51893/2021.4.OA4. eCollection 2021 Dec 6.
- Results publication: PubMed 39560150van Oosten JP, Akoumianaki E, Jonkman AH. Monitoring respiratory muscles effort during mechanical ventilation. Curr Opin Crit Care. 2025 Feb 1;31(1):12-20. doi: 10.1097/MCC.0000000000001229. Epub 2024 Nov 14.
- Individual participant dataSharing planned: No. This is a single-center physiological observational study with a modest sample size. No plan to share individual participant data outside the study team. Summary data will be available in publications
Related trials for Inspiratory Effort
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Association of Inspiratory Effort With Dyspnea During Assisted Mechanical Ventilation in Critically Ill Patients
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Nuanprae Kitisin principal investigator
Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Stepwise PSV adjustment protocol in people with Inspiratory Effort and Mechanical Ventilation, run by Mahidol University at 1 site in Thailand.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 18 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Thailand. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Nuanprae Kitisin, MD (+66896767706, nuanprae.kit@mahidol.ac.th), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Respiratory drive and inspiratory effort across pressure support levels (time frame: Baseline and during protocol sessions, up to 3 days after enrollment). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07199881, which also lists 6 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Nov 2025.