Flow Controlled Ventilation in Robot-assisted Laparoscopic Surgery
- Conditions
- Mechanical Ventilation ComplicationPostoperative Pulmonary Atelectasis
- Interventions
- Other: Pressure-controlled ventilationOther: Flow-controlled ventilation
- Registration Number
- NCT06256900
- Lead Sponsor
- Cantonal Hospital of St. Gallen
- Brief Summary
The optimization of ventilation is especially important during general anaesthesia, when active, physiologic respiration suspends and is replaced by non-physiologic mechanical positive pressure ventilation. Aiming at preserving compliance of lung tissue to guarantee an effective gas exchange is to avoid an excessive pressure application, especially in extreme positioning of the patient (Trendelenburg positioning) and/or pneumoperitoneum resulting in additional non-physiologic intrathoracic pressure. Perioperative lung protection strategies have steadily improved in recent years to reduce complications from mechanical ventilation, but postoperative pulmonary complications remain a risk factor for increased morbidity and mortality.
- Detailed Description
Mechanical ventilation is crucial during general anesthesia, with ongoing efforts to refine strategies for optimal respiratory support. Important articles on perioperative ventilation explored key aspects, including PEEP application, tidal volume effects, PPC after major surgeries, and perioperative oxygen titration to mitigate oxidative stress. PEEP plays a pivotal role in enhancing oxygenation and preventing atelectasis during mechanical ventilation. Landmark studies by the ARDS Network highlight the importance of customizing PEEP application. This tailored approach not only improves respiratory mechanics but also reduces the risk of barotrauma, underscoring the crucial impact of personalized PEEP strategies. Concurrently, adopting a lung-protective strategy with low tidal volumes, has proven effective in mitigating ventilator-induced lung injury. These strategies aim to strike a balance between optimal oxygenation and minimizing potential complications associated with mechanical ventilation. Despite advancements in perioperative care, PPC remain a concern, particularly following major surgical procedures. Recent investigations emphasize the multifactorial nature of these complications. Early identification of risk factors and meticulous monitoring are crucial to reducing the incidence of complications such as atelectasis, pneumonia, and respiratory insufficiency. Understanding the interplay between mechanical ventilation strategies and postoperative outcomes is essential for improving patient recovery. The pursuit of optimal oxygenation must be balanced against the potential for oxygen toxicity and oxidative stress. Available studies shed light on the delicate equilibrium required in maintaining adequate oxygen delivery while avoiding the detrimental effects of hyperoxia. Clinicians must consider individual patient factors and tailor oxygen therapy to prevent oxidative stress, which can contribute to tissue damage and compromise overall patient well-being. FCV is a new ventilation strategy designed to minimize the mechanical effects of perioperative ventilation on lung tissue. Compared to traditionally employed ventilation strategies, gas flow is controlled during both inspiration and expiration in FCV. In particular, the almost linear pressure drop during the expiratory phase of FCV has been shown in various ex vivo/experimental and clinical studies to improve gas exchange and the proportion of ventilated lung tissue.
Ongoing advancements in mechanical ventilation shape anesthesia practices with a focus on evidence-based approaches for patient safety. Building on prior findings, this study explores the benefits of the novel ventilation approach, FCV, aiming to reduce dissipative energy and alveolar stress. The investigators hypothesize positive impacts on perioperative ventilation, vital parameters, and a decreased incidence of PPC, contributing to overall postoperative morbidity and mortality reduction.
Recruitment & Eligibility
- Status
- WITHDRAWN
- Sex
- All
- Target Recruitment
- 774
- Patient undergoing elective robot-assisted laparoscopic surgery (either abdominal, urologic or gynecologic surgery) with a duration of expected ventilation of ≥ 90 minutes
- Male or female aged ≥ 18 years
- ASA Physical Status Classification System score I - III
- Must be willing and able to give written informed consent to participate in the study and agree to comply with the study protocol prior to initiation of any study-mandated procedure and study intervention
- Patient with weight < 40 kg ideal body weight
- ASA Physical Status Classification System score IV - VI
- Previous enrolment into the current study
- Enrolment of study investigator, his/her family members, employees and other dependent persons
- If female and of childbearing potential: known pregnancy or a positive urine pregnancy test (confirmed by a positive serum pregnancy test), or lactating
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Pressure-controlled ventilation Pressure-controlled ventilation Control intervention PCV (Dräger Medical, Atlan A350): lung-protective ventilation to current best practice. Settings determined by the attending anesthesiologist (based on the internal SOP: intraoperative ventilation in robot-assisted laparoscopic surgery). Flow-controlled ventilation Flow-controlled ventilation Experimental intervention FCV (EVONE, Ventinova Medical): PEEP and Peak inspiratory pressure titration guided by dynamic compliance.
- Primary Outcome Measures
Name Time Method Differences in the number of patients developing postoperative pulmonary complications to postoperative day 5/discharge Development of PPC (composite endpoint including pneumonia, bronchospasm, atelectasis, pulmonary congestion, respiratory failure, pleural effusion, pneumothorax, requirement for mechanical ventilation) within the first 5 postoperative days (or until discharge).
* Constant postoperative monitoring of clinical features indicating PPC
* EIT parameters indicating atelectasis (defined by EIT derived parameters Global Inhomogenity Index, Tidal Impedance Variation, end-expiratory lung impedance) measurement after arrival at the PACU.
* Requirement of additional oxygen will be evaluated after transfer to the PACU/ICU. Air test indicating additional oxygen requirement, SpO2 \<90% / \<88% in case of risk of hypercapnic respiratory failure.
* If unplanned and continued mechanical ventilation is required after surgery this will count as fulfilled primary endpoint.
- Secondary Outcome Measures
Name Time Method Differences in Clara-Cell 16 serum concentrations periprocedural Presence and increase of blood biomarkers indicating alveolar shear stress compared between groups. Blood samples will be required to determine CC16 (3x during the course of the study, approx. 5ml blood each).
* Baseline (during preoperative anaesthesia consultation or during preparations before induction of anaesthesia
* During intervention: ca. 60 minutes after final adjustments of Trendelenburg positioning/pneumoperitoneum
* After transfer to PACU/ICU respectivelyDifferences in area under the curve of postoperative modified Horovitz index first hour after surgery maximal area under the curve of SpO2/FiO2 compared between groups during first hour after surgery/arrival at the PACU. Derived from data recorded in the electronic anesthesia protocol.
Differences in end-tidal to capillary/arterial CO2 gradient periprocedural Maximal end-tidal to capillary/arterial CO2 gradient compared between groups. (Capillary blood gases can accurately reflect arterial pH, pCO2 and Hb. Because arterial cannulation is not mandatory in the patient population, the investigators choose to determine the end-tidal to arterial CO2 gradient by assessing capillary blood gas, which has been shown to accurately reflect arterial CO2). Derived from data recorded in the electronic anesthesia protocol.
Differences in minimal required intraoperative FiO2 concentration periprocedural Minimal required intraoperative FiO2 to ensure an adequate perioperative oxygenation (defined as min. oximetric SpO2 of \>94%). Derived from data recorded in the electronic anesthesia protocol.
Differences in perioperative ventilation/oxygenation parameters periprocedural Differences in perioperative ventilation and oxygenation parameters (minimal FiO2, min/max. PEEP, min/max. compliance), compared between groups. Data derived from the electronic anesthesia protocol.
Differences in parameters derived from the electrical impedance tomography periprocedural Comparison of spatial and regional ventilation patterns during intervention between groups. Comparison of respiratory system compliacen, end-expiratory lung volume between groups at baseline (before surgical procedures in supine position), during intervention (ca. 60 min after Trendelenburg/pneumoperitoneum) and after return to supine position/end of pneumoperitoneum.
Whether FCV has an influence on parameters visualized and measured by EIT, these data will be monitored and evaluated during (secondary outcome assessment) and after (primary outcome assessment) the intervention (measurements at: baseline - during intervention (60min after Trendelenburg/Pneumoperitoneum) - after Trendelenburg/Pneumoperitoneum - after arrival at PACU)