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

NCT ID: NCT07199881

Last Updated: 2025-09-30

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

40 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-09-20

Study Completion Date

2027-09-30

Brief Summary

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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.

Detailed Description

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Conditions

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Inspiratory Effort Mechanical Ventilation Major Abdominal Surgeries

Keywords

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Pressure support ventilation respiratory drive inspiratory effort mechanical ventilation Major Abdominal Surgery

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

DIAGNOSTIC

Blinding Strategy

NONE

Study Groups

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Single Cohort (Postoperative SICU patients on PSV >48h)

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.

Group Type EXPERIMENTAL

Stepwise PSV adjustment protocol

Intervention Type PROCEDURE

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.

Interventions

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Stepwise PSV adjustment protocol

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.

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

* 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

Exclusion Criteria

* 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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Siriraj Hospital

OTHER

Sponsor Role collaborator

Mahidol University

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Nuanprae Kitisin

Role: PRINCIPAL_INVESTIGATOR

Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University

Locations

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Faculty of Medicine, Siriraj Hospital, Mahidol University

Bangkok, Bangkoknoi, Thailand

Site Status

Countries

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Thailand

Central Contacts

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Nuanprae Kitisin, MD

Role: CONTACT

Phone: +66896767706

Email: [email protected]

Nattaya Raykateeraroj, MD

Role: CONTACT

Phone: +66993519963

Email: [email protected]

Facility Contacts

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Nuanprae Kitisin, MD

Role: primary

References

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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.

Reference Type RESULT
PMID: 39256677 (View on PubMed)

Miskovic A, Lumb AB. Postoperative pulmonary complications. Br J Anaesth. 2017 Mar 1;118(3):317-334. doi: 10.1093/bja/aex002.

Reference Type RESULT
PMID: 28186222 (View on PubMed)

Courtney 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.

Reference Type RESULT
PMID: 38342951 (View on PubMed)

Docci 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.

Reference Type RESULT
PMID: 39506755 (View on PubMed)

Al-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.

Reference Type RESULT
PMID: 38046681 (View on PubMed)

van 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.

Reference Type RESULT
PMID: 39560150 (View on PubMed)

Provided Documents

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Document Type: Study Protocol

View Document

Other Identifiers

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PSV-SICU_SIRIRAJ

Identifier Type: -

Identifier Source: org_study_id