Mechanical Power for Ventilatory Settings in Operating Room

Summary

Postoperative respiratory failure (PRF) is a dreaded complication that imposes a significant burden through unplanned admission to the ICU, post discharge disability and mortality. Despite widespread implementation of intraoperative lung-protective ventilation strategies over the past decade, results remain inconsistent. Interventions targeting individual parameters like tidal volume or positive end-expiratory pressure (PEEP) have shown equivocal results. The use of high PEEP and recruitment maneuvers raises safety concerns by possible negative hemodynamic effects. Recent studies suggest that individualizing ventilation strategies based on mechanical power-a composite parameter integrating tidal volume, plateau pressure, PEEP, and ventilator frequency-may better predict and help prevent PRF, independently of patients' baseline respiratory system compliance. These studies identified this parameter as interventional targets to reduce lung injury during mechanical ventilation. However, no multicenter randomized controlled trial has been performed in the field of ventilatory settings titration during invasive mechanical ventilation in operating room.

The investigators hypothesize that a ventilation strategy aimed at decreasing mechanical power will reduce the incidence of PRF and mortality in patients undergoing abdominal surgery, compared with a standard strategy using fixed tidal volume and PEEP

Conditions

• Postoperative Respiratory Failure
• Abdominal Surgery
• Postoperative Pulmonary Complications
• Morality

Interventions

PROCEDURE

Mechanical power-guided ventilatory strategy

1. Tidal volume 7ml/kg PBW and RR titrated for EtCO2 between 40-50mmHg. See calculated Mechanical power:0,049\*tidal volume\*RR\*driving pressure. 2. Set PEEP 15cmH2O and perform recruitment maneuver at 30cmH2O for 20s. Decrease PEEP from 15 by steps of 2cmH2O until the lower level of PEEP minimizing mechanical power. Note mechanical power. Stop maneuver and/or decrease level of PEEP if decrease\>20% of cardiac output during the maneuver, when compared to baseline. 3. Repeat this step using 9 ml/kg PBW and choose the optimal tidal volume with lowest mechanical power. During the surgery, adjust RR to maintain EtCO2 between 40-50mmHg, with an inspiratory-to-expiratory time ratio of 1:2 to 1:1, an end-inspiratory pause of 30%, an FiO2 adjusted to maintain SpO2≥94%. Recruitment maneuvers will be performed after intubation, in case of ventilator disconnection, coelioscopy insufflation, change of position, at the end of surgery, or if mechanical power \>30%.

PROCEDURE

Standard fixed ventilatory settings

Tidal volume 7 ml/kg predicted body weight, calculated according to a predefined formula: 50+0.91 x (centimeters of height - 152.4) for males and 45.5+0.91 x (centimeters of height - 152.4) for females, fixed PEEP between 6 and 8 cmH20, recruitment maneuvers at the discretion of the physician. The respiratory rate will be adjusted to maintain end-tidal partial pressure of CO2 between 30 and 40 mmHg, a target reported to be used by approximately 90% of physicians according to a recent online survey administered to French anesthesiologists via the French Society of Anesthesia \& Intensive Care Medecine (SFAR), which will be published soon, with an inspiratory-to-expiratory time ratio of 1:2 to 1:1, an end-inspiratory pause of 30 %, and an FiO2 adjusted to maintain SpO2 ≥ 94%. Mechanical power will not be measured during the surgery to avoid any modification of the ventilatory setting by the physician in charge.

Sponsors & Collaborators

• University Hospital, Montpellier

  lead OTHER

Principal Investigators

• Audrey DEBRUS, Dr · University Hospital, Montpellier

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-06-01

Primary Completion

2029-01-01

Completion

2029-01-01