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| Name | Class |
|---|---|
| Siriraj Hospital | OTHER |
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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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| 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 cmHâ‚‚O, -3 cmHâ‚‚O, +3 cmHâ‚‚O, +6 cmHâ‚‚O, 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. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Stepwise PSV adjustment protocol | 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. |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | Baseline and during protocol sessions, up to 3 days after enrollment |
| Measure | Description | Time Frame |
|---|---|---|
| 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. | Baseline and during protocol sessions, up to 3 days after enrollment |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Nuanprae Kitisin, MD | Contact | +66896767706 | nuanprae.kit@mahidol.ac.th | |
| Nattaya Raykateeraroj, MD | Contact | +66993519963 | nuanprae.kit@mahidol.ac.th |
| Name | Affiliation | Role |
|---|---|---|
| Nuanprae Kitisin | Department of Anesthesiology, Faculty of Medicine, Siriraj Hospital, Mahidol University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Faculty of Medicine, Siriraj Hospital, Mahidol University | Recruiting | Bangkok | Bangkoknoi | 10700 | Thailand |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 39256677 | Result | 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. | |
| 28186222 | Result | Miskovic A, Lumb AB. Postoperative pulmonary complications. Br J Anaesth. 2017 Mar 1;118(3):317-334. doi: 10.1093/bja/aex002. |
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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
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot | Yes | No | No | Study Protocol | Sep 17, 2025 | Sep 16, 2025 |
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| 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. | 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. | 48 hours after extubation |
| ICU length of stay | Total number of days from ICU admission to ICU discharge. | 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). | Through hospital stay, an average of 14-60 days |
| 38342951 | Result | 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. |
| 39506755 | Result | 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. |
| 38046681 | Result | 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. |
| 39560150 | Result | 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. |
| Prot_000.pdf |