Emergency Abdominal Surgery, Mechanical Ventilation, General Anesthesia, Postoperative Morbidity
Conditions
Keywords
Mechanical Ventilation, Lung-Protective Ventilation, Postoperative Pulmonary Complications, Postoperative morbidity
Brief summary
The aim of this study is to compare the effects of a strategy aimed at increasing alveolar recruitment (high PEEP levels adjusted according to driving pressure and recruitment maneuvers) with that of a strategy aimed at minimizing alveolar distension (low PEEP level without recruitment maneuver) on postoperative respiratory failure and mortality in patients receiving low VT ventilation during emergency abdominal surgery.
Detailed description
Emergency abdominal surgery is associated with a high risk of morbidity and mortality. Postoperative pulmonary complications (PPCs) are the second most common surgical complication and adversely influence surgical morbidity. Postoperative respiratory failure (PRF) is one of the most serious pulmonary complication. Two hypotheses can be forward by the literature. First, a low VT lung protective ventilation in combination with a strategy aimed at minimizing alveolar distension by using low PEEP level (and without recruitment maneuver) could improve postoperative outcome while reducing the risk of hemodynamic alterations or, second, could increase the risk of PRF compared with a strategy aimed at increasing alveolar recruitment using higher PEEP level adjusted according to driving pressure in combination with recruitment maneuvers in adult patients undergoing emergency abdominal surgery. Given the uncertainties, and in order to determine the impact of lung protective ventilation strategies on clinical outcomes of high-risk surgical patients, a randomized trial is needed. Our primary hypothesis is that, during low VT ventilation, a strategy aimed at increasing alveolar recruitment by using high PEEP levels adjusted according to driving pressure in combination with recruitment maneuvers could be more effective at reducing PRF and mortality after emergency abdominal surgery than a strategy aimed at minimizing alveolar distension by using lower PEEP without recruitment maneuver. Given the number of patients for whom the question applies, the prevalence and the burden of PPCs, the study can have significant clinical importance and public health implications.
Interventions
OTHERDriving-pressure-guided group
Patients will receive PEEP levels individually set at the highest possible value (up to 15 cmH2O) providing a driving pressure (airway plateau pressure minus PEEP) lower than 13 cmH2O, in addition to recruitment maneuvers.
OTHERLow PEEP
Patients will receive a PEEP level ≤5 cmH2O without recruitment maneuvers
Sponsors
University Hospital, Clermont-Ferrand
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Outcomes Assessor)
Masking description
It will not be possible to mask the assigned ventilation strategy from the treating clinicians because they have an ethical responsibility to ensure patient safety during the emergency procedures. However, procedures will be put in place to minimize the possibility of bias arising because research staff becomes aware of trial group allocation. At each participating center, patients will be followed up for primary and secondary endpoints by members of the research staff who will be unaware of the trial group allocation. Information on whether the primary and secondary outcomes occur will be collected and entered into the electronic web-based case report form (eCRF) by trial or clinical trained personal (clinical research associate), blinded to the allocation group, under the supervision of the local principal investigator (PI) or designee who will also be unaware of the trial group allocation.
Intervention model description
Multicenter, prospective, randomized, stratified, parallel-group clinical trial with blinded outcome assessment and concealed allocation of patients undergoing emergency abdominal surgery using low VT lung-protective ventilation to a strategy of minimal alveolar distension using low PEEP level or to a strategy aimed at increasing alveolar recruitment (higher PEEP level individually titrated to minimize the driving pressure in addition to recruitment maneuvers)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Adult (≥18 years) * Patients requiring emergency (defined by the need to proceed to surgery within a few hours after diagnosis) * Laparoscopic or non-laparoscopic abdominal surgery under general anesthesia and with an expected duration of at least two hours
Exclusion criteria
* Patients already receiving mechanical ventilation for more than 12 hours before enrollment * Intracranial hypertension * Chronic respiratory disease requiring oxygen therapy or mechanical ventilation at home * Undrained pneumothorax or subcutaneous emphysema * Patients for which death is deemed imminent and inevitable or patients with an underlying disease process with a life expectancy of less than 3 month * Body mass index (BMI) \>40 kg/m2 * Pregnant or breastfeeding women * Patients already enrolled in the IMPROVE-2 trial * Participation in a confounding trial with mortality or PRF as the main endpoint * Patient's or relative's refusal to participate * Guardianship or trusteeship patient * No affiliation to the Social Security system
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative respiratory failure | Hospital discharge - Up to day 30 | Composite criteria : 1. \- Failure to wean from the ventilator after surgery (Yes or No) 2. \- Requiring unplanned reintubation (Yes or No) 3. \- Curative non-invasive ventilation once extubated postoperatively (Yes or No) 4. \- Death (all cause of mortality) (Yes or No) If at least one of these 4 criteria is answered yes, the composite criterion (i.e. the primary outcome) will be answered yes |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative extra-pulmonary complications | Day 30 | sepsis and septic shock, renal dysfunction |
| SOFA | Day 1 | Sequential-related Organ Failure Assessment |
| Ventilator-free days | Day 30 | The number of days alive and with unassisted breathing |
| Duration of invasive mechanical ventilation | Up to Day 30 | Duration of invasive mechanical ventilation from randomization to first tracheal extubation |
| Total duration of mechanical ventilation | Up to Day 30 | Total duration of mechanical ventilation (additive, for all épisodes) |
| Time to successful tracheal extubation | 48 hours | Absence of ventilatory support during the first 48 hours after extubation |
| Total volume of intraoperative fluids | Day 1 | Total volume of intraoperative fluids (crystalloids and colloids) |
| Median norepinephrine doses during surgery | Day 1 | µg/kg/min |
| Postoperative pulmonary complications | Day 30 | Hypoxemia, pneumonia? development of acute respiratory distress syndrome (ARDS) |
| Median ephedrine doses during surgery | Day 1 | µg/kg/min |
| Intensive care unit (ICU)-free days | Day 30 | Intensive care unit (ICU)-free days |
| Duration of ICU stay | Up to day 90 | Duration of ICU stay |
| Duration of hospital stay | Up to day 90 | Duration of hospital stay |
| All-cause mortality | Day 30 | All-cause mortality |
| Time to death | Up to 90 days | Time to death (Days) |
| Hemodynamic instability | Up to day 30 | Hemodynamic instability ventilatory-related defined as a drop of arterial systolic pressure below 80 mmHg for more than 5 minutes not responding to treatment |
| Pneumothorax | Up to day 30 | Pneumothorax ventilatory-related |
| Median phenylephrine doses during surgery | Day 1 | µg/kg/min |
Countries
France
Outcome results
None listed