About this trial

The investigators want to investigate in patients undergoing robot-assisted laparoscopic surgery (a minimally invasive procedure) how applicable flow-controlled ventilation is, and whether it might also be safer than the current ventilation techniques, as well as its impact on potentially reducing the risk of lung-specific complications.

Flow-controlled ventilation has already been tested in several studies on animals and humans and has proven to be a safe form of ventilation for patients undergoing surgery under general anesthesia.

When patients undergo major surgery, general anesthesia is required and, as a result, mechanical ventilation of the lungs. Especially in long and complex surgeries, ventilation can become more difficult or lead to complications postoperatively. These patients may then experience shortness of breath, coughing, or require medication to improve lung function. In some cases, reintubation or additional mechanical ventilation may be necessary for support.

Previous human studies have shown that flow-controlled ventilation is less stressful and, therefore, potentially safer for the lungs compared to traditional ventilation techniques, and that less supplemental oxygen is required. This effect and the safety of flow-controlled ventilation have been demonstrated in several studies.

Therefore, in this study, the investigators aim to explore whether flow-controlled ventilation is potentially safer and easier to apply than traditional ventilation techniques and whether it can reduce the risk of lung-specific complications following robot-assisted surgeries, thereby improving the recovery process postoperatively.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

undergoing elective robot-assisted laparoscopic surgery in supine or Trendelenburg position (either abdominal, urologic or gynecologic surgery);

AND increased risk of PPCs according to the ARISCAT risk score (≥ 26 points);

OR the combination of age > 40 years, scheduled surgery lasting > 2 hours and planned to receive an intra-arterial catheter for blood pressure monitoring during the surgery;

aged ≥ 18 years; and

Disqualifiers

ideal body weight < 40 kg;

ASA Physical Status Classification System score IV - VI;

previous enrolment into the current study;

being the study investigator, his/her family members, employees and other dependent persons;

Trial design

Design model

Parallel

Treatments tested in this trial

Intraoperative flow-controlled ventilation strategy
Other intervention
In the FCV group, intraoperative ventilation will be provided with the EVONE (IES Ventinova Medical).PEEP and Ppeak are titrated guided by dynamic compliance, as follows: Starting from a default setting of 5 cmH2O of PEEP and 15 cmH2O of Ppeak, PEEP and Ppeak are equally increased by 1 cmH2O steps and the PEEP value with the highest VT and thus highest dynamic compliance is defined as "best" PEEP. Subsequently, Ppeak is stepwise (+1 cmH2O) increased until there is no further over-proportional increase in tidal volume (VT) (i.e. measured VT \> expected VT according to measured dynamic compliance), defined as best driving pressure. No recruitment maneuvers are carried out during FCV. With the I:E ratio set to 1:1, flow is adjusted to establish normocapnia (target etCO2 4.5 to 5.8 kPa). FiO2 is adjusted to maintain oxygen saturation (SpO2) \> 92%.
Intraoperative pressure-controlled ventilation strategy
Other intervention
In the PCV group, intraoperative ventilation will be provided by a standard anesthesia ventilator in use in the respective participating centers. Patients will be ventilated in PCV mode, at the lowest inspired oxygen fraction (FiO2), to maintain oxygen saturation (SpO2) \> 92%. It is left to the discretion of the attending anesthesiologist to use a higher fraction of FiO2. Inspiratory to expiratory ratio is set at 1:1 to 1:2, respiratory rate will be adjusted to target normocapnia (target etCO2 4.5 to 5.8 kPa. VT will be set at 7 to 9 ml/kg predicted body weight (PBW). The PBW is 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. Ventilation starts with 5 cm H2O PEEP, and can be increased to 10 cm H2O PEEP.

Treatment groups

100 Participants

are divided into 2 treatment groups

Group A: Intraoperative flow-controlled ventilation FCVExperimental treatment 1 intervention

Group B: Intraoperative pressure-controlled ventilation PCVActive comparator 1 intervention

Trial outcomes

Primary outcomes

1

Safety of intraoperative FCV

The primary objective of this pilot trial is to evaluate the safety of intraoperative FCV in patients undergoing robot-assisted laparoscopic surgery. Herein the investigators focus on, gas exchange, including both oxygenation and decarboxylation; minute ventilation, during all phases of intraoperative ventilation; key ventilator settings and ventilation parameters; respiratory complications, including pneumothorax and hemodynamic complications, including hypotension and arrhythmias.

Time frame

After induction of general anesthesia and beginning of intraoperative mechanical ventilation to the end of surgery and the end of mechanical ventilation (up to a duration of 12 hours of mechanical ventilation).

Secondary outcomes

1

feasibility of intraoperative FCV, study protocol and database completeness

Secondary objectives of this pilot trial are to assess the feasibility of intraoperative FCV in patients undergoing robot-assisted laparoscopic surgery, the feasibility of the study protocol and its electronic case report form (eCRF). Herein the investigators focus on: the need for rescue ventilation strategies, i.e., whether FCV (as well as PCV) can be used during all phases of intraoperative ventilation; and compliance with the study protocol, omissions in the eCRF, and the feasibility of follow-up, i.e., how well each postoperative pulmonary complication can be captured.

Time frame

After induction of general anesthesia and beginning of intraoperative mechanical ventilation to the seventh postoperative day or until end of hospitalization, whatever comes first (i.e., up to 7 days after surgery)

Other outcomes

1

Explorative objective incidence of PPC

Another secondary objective concerns the primary endpoint of a future randomized clinical trial testing the efficacy of FCV, i.e., its effects on postoperative pulmonary complications. Herein the investigators will focus on: the incidence of PPCs in the FCV group and the PCV group, to inform the sample size calculation of the future trial.

Time frame

After induction of general anesthesia and beginning of intraoperative mechanical ventilation to the seventh postoperative day or until end of hospitalization, whatever comes first (i.e., up to 7 days after surgery)

PROtective Ventilation With FLOW-Controlled Ventilation

About this trial

Eligibility criteria

Qualifiers

Disqualifiers

Trial design

Treatments tested in this trial

Treatment groups

Trial outcomes

Primary outcomes

Secondary outcomes

Other outcomes

Sponsors and contacts