Assessment of Ventilatory Management During General Anesthesia for Robotic Surgery

Research questions:

1. What is the incidence of PPC in patients undergoing mechanical ventilation during
general anesthesia for robotic surgery?

2. Are the outcomes in patients undergoing robotic surgery dependent on ventilation
practice and surgical positioning?

3. What is the incidence of patients at high risk for PPC undergoing robotic surgery

Methods:

In this international observational study, consecutive patients undergoing mechanical
ventilation for robotic surgery are eligible for participation. Patients in participating
centers will be screened on a daily basis. Patients undergoing mechanical ventilation for
robotic surgery will be included during a 30-day period. The inclusion period will be
flexible for participating centers and determined at a later stage together with the
study-coordinator.

Time points of data collection:

1. Demographic data and baseline data, including severity scores (e.g. ASA) and ARISCAT,
are collected from the clinical files on the day of surgery

2. Ventilation settings, gas exchange variables, positioning and vital parameters are
collected hourly during surgery

3. Chest radiography data from available chest X-rays (i.e., no extra chest X-rays are
obtained)

4. Predefined complications are recorded from medical chart until the first five
postoperative days, discharge from hospital or death, whatever comes first

5. Length of hospital stay, and hospital mortality

Centres: The investigators aim to recruit 20 - 50 centers worldwide.

Ethics Approval: National coordinators will be responsible for clarifying the need for ethics
approval and applying for this where appropriate according to local policy. Centres will not
be permitted to record data unless ethics approval or an equivalent waiver is in place. The
investigators expect that in most, if not every participating country, a patient informed
consent is not be required.

Monitoring: Due to the observational nature of the study, a DSMB is not be necessary.

Study Population: Adult patients undergoing mechanical ventilation for robotic surgery.

Data Collection: Data will be collected at inclusion, during surgery and every day during
five days, and day of hospital discharge. Data will be coded by a patient identification
number (PIN) of which the code will be kept safe at the local sites. The data will be
transcribed by local investigators onto an internet based electronic CRF.

Sample Size Calculation: A formal sample size will not be calculated, seen the largely
descriptive character of this investigation. Data from 500 patients is expected to be
collected, which will be sufficient to test the hypotheses.

Statistical Analysis: Patient characteristics will be compared and described by appropriate
statistics. Student's t-test or Mann-Whitney U-tests are used to compare continuous variables
and chi-squared tests are used for categorical variables. Data are expressed as means (SD),
medians (interquartile range) and proportions as appropriate. Comparisons between and within
groups are performed using one-way ANOVA and post-hoc analyses for continuous variables.

The primary analysis concerns the determination of the incidence of postoperative pulmonary
complications in patients undergoing mechanical ventilation for robotic surgery.

To identify potential factors associated with outcome like development of postoperative
pulmonary complications, or death, univariable analyses will be performed. A multi-level
multivariable logistic regression model will be used to identify independent risk factors. A
gradual approach will be used to enter new terms into the model, with a limit of p < 0.2 to
enter the terms. Time to event variables will be analyzed using Cox regression and visualized
by Kaplan-Meier.

Organization: The study is conducted by the PROtective VEntilation Network (PROVENet).
National co-ordinators will lead the project within individual nations and identify
participating hospitals, translate study paperwork, distribute study paperwork and ensure
necessary regulatory approvals are in place. They provide assistance to the participating
clinical sites in trial management, record keeping and data management. Local coordinators in
each site will supervise data collection and ensure adherence to Good Clinical Practice
during the trial.

Inclusion Criteria:

- Age ≥ 18 years

- All surgical procedures performed under general anesthesia for robotic surgery,
including head and neck operations, chest, cardiac, and abdominal surgeries

Exclusion Criteria:

- Any procedure during pregnancy

- Procedures outside of the operating room