Flow Controlled Ventilation Versus Pressure Controlled Ventilation in Thoracic Surgery With One Lung Ventilation - a Prospective, Randomized Clinical Study

Brief Summary

Detailed Description

Flow-controlled ventilation (FCV) is a novel ventilation method with promising first results in porcine studies as well as clinical cross-over trials. A more efficient and maybe lung protective ventilation strategy would be crucial in the challenging situation of one lung ventilation during thoracic surgery, when the whole gas exchange has to be provided by just one half of the lungs. Thus, individualized FCV, based on compliance guided pressure settings, will be compared to standard of pressure-controlled ventilation in thoracic surgery requiring one lung ventilation in a randomized controlled trial. Based on previous preclinical trials an improvement of oxygenation by 15% will be expected and in order to transfer the preclinical results to humans oxygenation assessed by paO2 / FiO2 ratio after 30 minutes of one lung ventilation is the main primary outcome parameter of this study. Furthermore, improved recruitment of lung tissue due to controlled expiratory flow in FCV will be anticipated without the need of recruitment maneuvers, which may cause deleterious effects on lung tissue. Accordingly any recruitment maneuvers will be omitted in the FCV group. The investigators hypothesize that improved gas exchange in terms of improved oxygenation and reduced respiratory minute volume required for CO2-removal will be achieved with FCV compared to PCV. Secondary outcome parameters such as the incidence of postoperative pulmonary complications will be additionally assessed in order to plan future studies with clinically relevant outcome.

Primary Outcomes

Secondary Outcomes

• tidal volume(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• respiratory compliance(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• positive end-expiratory pressure(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• peak pressure(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• driving pressure(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• applied mechanical power(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• respiratory resistance(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• mean arterial pressure(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• length of PACU stay(Time from PACU admission to transfer to a general ward in hours)
• central venous pressure(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• Concentration of plamatic cytokine levels(preoperative before induction of general anesthesia and postoperative at PACU admission and 1 hour thereafter)
• length of hospital stay(days from surgery to hospital discharge)
• postoperative pulmonary complications (PPC)(until hospital discharge or day 30 of hospital stay)
• decarboxylation (paCO2)(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• venous admixture (Qs / Qt)(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• respiratory minute volume(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• respiratory rate(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))
• heart rate(during two lung ventilation in supine position after anesthesia induction (T1) and change to lateral position (T2), after 15 (T3), 30 (T4) and 60 minutes (T5) of one lung ventilation and after reinflation before tracheal extubation (T6))