Prophylactic Use of APRV Before Extubation in Morbidly Obese Patients After Cardiac Surgery.

Summary

Morbidly obese patients undergoing open heart surgery are at increased risk of breathing problems after removal of the breathing tube due to reduced lung function and chest wall restriction following surgery. These complications may result in poor oxygenation, respiratory failure, and prolonged ICU stay.

Airway Pressure Release Ventilation (APRV) is a mechanical ventilation mode that improves lung recruitment and oxygenation. This study aims to evaluate whether the prophylactic use of APRV after ICU admission, compared with conventional lung-protective mechanical ventilation, improves oxygenation, lung function, and ICU outcomes in morbidly obese patients undergoing elective cardiac surgery.

Patients will be randomly assigned to receive either APRV or conventional ventilation during postoperative mechanical ventilation, followed by standard weaning and extubation. Outcomes include oxygenation index, lung ultrasound findings, need for reintubation, and ICU clinical outcomes.

Conditions

• Morbid Obesity in Cardiac Surgery Patients
• Postoperative Respiratory Dysfunction
• Mechanical Ventilation Strategies

Interventions

DEVICE

Airway Pressure Release Ventilation (APRV)

Patients will be ventilated using the Airway Pressure Release Ventilation (APRV) mode immediately upon ICU admission. This mode will be maintained throughout the postoperative period until the patient meets the clinical criteria for extubation. with the following standardized steps: Initial APRV Settings * P High: 20-25 cm H₂O * P Low: 0 cm H₂O * T High: 4.0-6.0 seconds * T Low: 0.5-0.8 seconds * FiO₂: Adjusted to maintain SpO₂ \>92% Note: P High may be titrated according to patient tolerance, Mean airway pressure (MAP), and plateau pressures. T Low is set to terminate expiratory flow at 50-75% to preserve lung recruitment. Weaning/Transition from APRV to Extubation Once oxygenation and ventilation criteria are met: * T High will be gradually increased (to ≥8 sec) and P High decreased (to 10-15 cm H₂O) * Then transition to CPAP/PS for 15-30 minutes Final decision for extubation will be based on successful spontaneous breathing trial (SBT) (RSBI \< 105) and clinical readiness

DEVICE

Conventional Lung-Protective Mechanical Ventilation

Patients will be ventilated using the SIMV Volume-Controlled mode with lung-protective strategies: * Tidal volume: 6-8 mL/kg of Ideal Body Weight (IBW) * PEEP: Set at 8-12 cm H₂O, individualized based on oxygenation status * Respiratory rate: Adjusted to maintain normocapnia, typically starting from 12-18 breaths per minute * FiO₂: Titrated to maintain SpO₂ \> 92% * Also transition to CPAP/PS for 15-30 minutes as a transition before extubation will be applied.

Sponsors & Collaborators

• Ain Shams University

  lead OTHER

Principal Investigators

• Aya M Abbas, M.B.B.CH., M.Sc · Ain Shams University

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-02-01

Primary Completion

2026-10-31

Completion

2026-11-30