Optimizing Intraoperative Mechanical Ventilation Using EIT-titrated PEEP
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|ClinicalTrials.gov Identifier: NCT02314845|
Recruitment Status : Completed
First Posted : December 11, 2014
Last Update Posted : May 12, 2016
|Condition or disease||Intervention/treatment||Phase|
|Pulmonary Atelectasis||Other: Optimal PEEP Other: Low PEEP||Not Applicable|
Patients submitted to general anesthesia and mechanical ventilation commonly develop pulmonary atelectasis, which can cause adverse consequences either intraoperatively or postoperatively. The use of lower, more physiological tidal volumes (6-8 mL/Kg of ideal body weight) during the intraoperative period can minimize the risk of lung injury but may be associated with increased atelectasis. The application of PEEP can prevent the formation of atelectasis and minimize the resulting complications, but at the present time, there is no consensus on how to tailor the level of PEEP to best suit each patient.
Electrical Impedance Tomography (EIT) is a portable non-invasive monitor that enables the analysis of lung function in a continuous mode.
The aim of this study is to evaluate the use of Electrical Impedance Tomography (EIT), in the intraoperative period, as a tool for selecting "optimal PEEP" using a PEEP titration procedure, as well as assessing the evolution of pulmonary function during this period.
The investigators will prospectively study a total of 40 adult patients (> 18 years) divided into two subgroups: 20 laparoscopic surgery patients and 20 open surgery patients. After induction of anesthesia and neuromuscular blockade, all patients will be submitted to a recruitment maneuver in pressure-controlled ventilation (PCV) mode (PEEP = 20cmH2O, driving pressure = 20cmH2O, respiratory rate (RR) of 15 ipm and I:E ratio of 1:1) for 2 minutes followed by a decremental PEEP titration. The first step of the titration will start at a PEEP of 20 cmH2O and every 40 seconds PEEP will be decreased by 2 cmH2O, until a final PEEP of 4 cmH2O. A sub-sample of patients will have each step of the PEEP titration procedure recorded with an ultrasound and later evaluated by two different investigators. Optimal PEEP will be defined as that with the best compromise of atelectasis and overdistension as measured by EIT.
Patients in each subgroup will be randomized to one of two ventilatory strategies: (1) PEEP chosen by the PEEP titration procedure; (2) PEEP set at 4 cmH2O. After a new recruitment maneuver PEEP will be set at the designated value and the patient will be ventilated with an inspired oxygen fraction of 50% or greater in order to maintain peripheral oxygen saturation (SpO2) > 96%, a tidal volume of 6 mL/Kg and a respiratory rate to maintain an end tidal carbon dioxide (ETCO2) between 35-45.
All patients will have their global and regional pulmonary mechanics monitored by EIT throughout the anesthetic procedure to assess the degree of pulmonary atelectasis. After extubation, patients will be referred to the Radiology Department for a chest CT.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||40 participants|
|Intervention Model:||Parallel Assignment|
|Official Title:||Optimizing Intraoperative Mechanical Ventilation Using EIT-titrated PEEP|
|Study Start Date :||August 2014|
|Actual Primary Completion Date :||April 2016|
|Actual Study Completion Date :||April 2016|
Experimental: Optimal PEEP
Patients submitted to general anesthesia and abdominal laparoscopic surgery (number=10) or open surgery (number=10) will be submitted to a recruitment maneuver followed by a PEEP titration procedure using Electrical Impedance Tomography (EIT). Patients will be mechanically ventilated during intraoperative period using "Optimal PEEP" determined by Electrical Impedance and FIO2 of 0.5.
Other: Optimal PEEP
"Optimal PEEP" determined by EIT during a PEEP titration procedure.
Patients submitted to general anesthesia and abdominal laparoscopic surgery (number=10) or open surgery (number=10) will be submitted to a recruitment maneuver followed by a PEEP titration procedure EIT. In this arm, the ventilator will be set with a PEEP=4 cmH2O ("Low PEEP") and FIO2 of 0.5 during intraoperative period.
Other: Low PEEP
Use of PEEP of 4 cmH2O during intraoperative period
- Optimal PEEP value [ Time Frame: 6 minutes ]The PEEP value, for each patient, that produces the best possible compromise of lung collapse and lung hyperdistention during a PEEP titration procedure using EIT
- Pulmonary atelectasis [ Time Frame: 2-5 hours ]The amount of atelectasis, in percentage of lung mass, evaluated by EIT during intraoperative period and by chest CT scan after extubation
- Ultrasound evaluation [ Time Frame: 6 minutes ]The use of ultrasound as a tool for PEEP titration intraoperatively compared to EIT
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02314845
|University of Sao Paulo General Hospital|
|Sao Paulo, SP, Brazil|
|Principal Investigator:||Joaquim E Vieira, MD, PhD||University of Sao Paulo General Hospital|