Critical Ill Patients in SICU, Upper Abdominal Surgery
Conditions
Keywords
pulmonary complication, postoperative care, upper abdominal surgery
Brief summary
The VALUE Study is a two-phase, prospective clinical trial conducted at King Chulalongkorn Memorial Hospital (KCMH). The study evaluates the prevalence of mechanical ventilation (MV) separation failure in post-open upper abdominal surgery patients and investigates whether non-invasive bedside respiratory monitoring tools can rapidly predict extubation failure. The protocol focuses on Electrical Impedance Tomography (EIT) metrics-specifically regional ventilation distribution and the absolute ventral-to-dorsal difference-alongside ventilator-derived measures of respiratory drive. It also tracks physiological responses and clinical outcomes, including dyspnea using the Intensive Care Respiratory Distress Observation Scale (IC-RDOS) and the ROX index, across standard post-extubation oxygen delivery methods (nasal cannula vs. High-Flow Nasal Cannula \[HFNC\]).
Detailed description
Postoperative patients undergoing upper abdominal surgery frequently require mechanical ventilation and are at increased risk of extubation failure because of impaired respiratory mechanics, postoperative pain, diaphragmatic dysfunction, and atelectasis. Failure of separation from mechanical ventilation is associated with prolonged intensive care unit (ICU) stay, increased healthcare utilization, and mortality. Although prophylactic high-flow nasal cannula (HFNC) is commonly used to reduce the risk of respiratory deterioration after extubation, clinicians currently lack reliable bedside tools that provide real-time physiological information to predict successful separation from mechanical ventilation and guide individualized respiratory support. A preceding quality improvement audit conducted at King Chulalongkorn Memorial Hospital demonstrated a composite post-extubation failure rate of approximately 32% among postoperative upper abdominal surgery patients requiring mechanical ventilation. In addition, the investigators' precursor VISION study showed that an electrical impedance tomography (EIT)-derived absolute ventral-to-dorsal ventilation difference greater than 20% during a spontaneous breathing trial was associated with failure of liberation from mechanical ventilation. These findings provide the rationale for evaluating non-invasive physiological monitoring in this high-risk surgical population. The VALUE study is a prospective, two-phase clinical investigation designed to determine the prevalence of separation failure from mechanical ventilation and to evaluate the predictive performance of non-invasive respiratory monitoring parameters. The study will enroll approximately 40 adult patients who require postoperative mechanical ventilation following upper abdominal surgery. During the first phase, participants will undergo physiological assessment while receiving mechanical ventilation during spontaneous breathing. An EIT belt will be applied to continuously measure regional lung ventilation. Simultaneously, ventilator-derived indices of respiratory drive and inspiratory effort, including airway occlusion pressure (P0.1) and end-expiratory occlusion pressure-derived measurements (ΔPocc), will be recorded using standardized measurement procedures. Following successful extubation, participants will enter the second phase, which consists of a prospective physiological crossover study. Oxygen therapy will be administered according to routine clinical practice, with the treating clinical team selecting the initial oxygen delivery device. Participants will then undergo an ABA crossover sequence between conventional nasal prong oxygen therapy and high-flow nasal cannula, with each intervention maintained for a standardized 10-minute period. This design allows comparison of physiological responses while minimizing potential carryover effects without requiring an unsafe room-air washout period. Throughout both study phases, EIT will continuously measure regional ventilation distribution, while additional non-invasive physiological variables, including respiratory drive, inspiratory effort, respiratory rate, oxygenation indices, and clinical respiratory distress scores, will be collected using standardized protocols. Participants will be followed for seven days after extubation to evaluate clinical outcomes related to separation from mechanical ventilation and postoperative pulmonary complications. The study is designed to determine whether bedside physiological monitoring using EIT and complementary non-invasive respiratory measurements can improve prediction of successful separation from mechanical ventilation and provide insights into the physiological effects of different post-extubation oxygen delivery strategies in patients undergoing upper abdominal surgery.
Interventions
DEVICEHigh Flow Oxygen
If HFNC is used as the first device, the settings will be determined at the discretion of the clinical team. -If HFNC is used as the second device, the oxygen concentration (FiO₂) will be set equivalent to that of the nasal prong (using estimated FiO2 = current FiO2 + 0.03 \*O2 flow rate (L/min))(27), with a flow rate of 50 L/min. This is based on a 6-month SICU observation showing that nearly all patients after ventilator weaning were initially set on HFNC at 50 L/min and subsequently weaned down with FiO2 30-40%. This approach allows the HFNC settings to be as consistent as possible with routine attending physician practice and ensures that patients in this study receive HFNC settings that are as uniform as possible, without interfering with the primary treatment plan.
DEVICENasal canula oxygen
if nasal prong is used as the first device, the setting will be determined at the discretion of the clinical team. If nasal prong is used as the second device, the FiO₂ will be set with a flow rate of 5 LPM (will be equivalent 40% of FiO2)
Sponsors
Papawee Chennavasin
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age of ≥ 18 years * Post elective open upper abdominal surgery with mechanical ventilation * Get readiness for mechanical ventilation weaning with pressure support 5-8 cmH2O and PEEP 5-8 cmH2O set by clinical team and prompt extubation assessed by clinical team
Exclusion criteria
* Previous tracheostomy * Contraindication to EIT placement: pacemaker/defibrillator implantation, burns at the area of EIT placement * Patient with end-of-life plan * Emergency operation
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| The prevalence of success vs failure after extubation | 7 days | MV separation failure including i) reintubation within 7 days after extubation, ii) death within 7 days after extubation, iii) tracheostomy without trying extubation, or iv) step-up to use HFNC due to worsening respiratory symptoms (decided by clinical team) in patients using nasal prong within 7 days after extubation |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Post extubation pulmonary complications | 7 days | new pneumonia - clinical of pulmonary infection (fever, cough, purulent secretion, dyspnea, and/or desaturation) with new pulmonary infiltrations; new pulmonary edema - clinical of dyspnea, cough, orthopnea/PND, with congestive pulmonary edema radiographic patterns; new pleural effusion - seen from radiographic imaging which it has never presented pre-operation or immediate post operation (before extubation); new atelectasis by radiographic imaging which it has never presented pre-operation or immediate post operation (before extubution), occurs 7 days from post-extubaton. |
| Duration of MV | 30 days | Duration of MV after extubation |
| ICU length of stay | 30 days | Total days from immediate postoperative ICU admission to discharge from ICU |
Contacts
CONTACTPapawee Chennavasin, MD
Outcome results
None listed