PROtective Ventilation With FLOW-Controlled Ventilation

Condition(s) studied

Investigational drug(s) / intervention(s)

Intraoperative flow-controlled ventilation strategy: 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: 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.

Study summary

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

Primary outcome measure(s)

• Safety of intraoperative FCV — 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).
  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.

Trial sites (3)

More Cantonal Hospital of St. Gallen trials in Austria

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