Optimizing Intraoperative Mechanical Ventilation Using EIT-titrated PEEP

Pulmonary Atelectasis Clinical Trial

Official title:

Optimizing Intraoperative Mechanical Ventilation Using EIT-titrated PEEP

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT02314845
• Other study ID #: CAAE_13768713.0.0000.0068
• Status: Recruiting
• Phase: N/A
• First received: November 7, 2014
• Last updated: November 25, 2015
• Start date: August 2014
• Est. completion date: July 2016

Study information

• Verified date: November 2015
• Source: University of Sao Paulo General Hospital
• Contact: Joaquim E Vieira, MD, PhD
• Phone: 55 11 30617472
• Email: joaquimev[@]usp.br
• Is FDA regulated: No
• Health authority: Brazil: Ministry of Health
• Study type: Interventional

Clinical Trial Summary

The purpose of this randomized single center study is to determine the individual PEEP value that produces the best possible compromise of lung collapse and lung hyperdistention. Patients submitted to general anesthesia and mechanical ventilation during surgery (laparoscopy and open surgery) will participate. A PEEP titration procedure will be performed and the "optimal PEEP" value will be determined by electrical impedance tomography (EIT). An ultrasound will be used to record each step of the PEEP titration procedure in a sub-sample of patients. A total of 40 patients will be mechanically ventilated using physiological tidal volume (TV=6mL/kg of IBW) and fraction of inspired oxygen (FIO2) of 0.5 and will be randomized to one of two groups: "optimal PEEP" or a "low PEEP" (4cmH2O). Lung collapse and mechanics will be monitored by EIT throughout the intraoperative period. After extubation, a lung CT will be performed to evaluate the amount of lung collapse.

Description:

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 40
• Est. completion date: July 2016
• Est. primary completion date: December 2015
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Patients submitted to general anesthesia for surgical procedure

Exclusion Criteria:

• Age < 18 years

• Thoracic surgery (any)

• ASA grade III or IV

• History of moderate/severe chronic obstructive pulmonary disease (COPD) or moderate/severe Asthma

• Moderate/severe restrictive lung disease

• Use of heart pacemaker

Study Design

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Single Blind (Subject), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Pulmonary Atelectasis

Intervention

Other:
• Optimal PEEP
"Optimal PEEP" determined by EIT during a PEEP titration procedure.
• Low PEEP
Use of PEEP of 4 cmH2O during intraoperative period

Locations

Country	Name	City	State
Brazil	University of Sao Paulo General Hospital	Sao Paulo	SP

Sponsors (2)

Lead Sponsor	Collaborator
University of Sao Paulo General Hospital	Fundação de Amparo à Pesquisa do Estado de São Paulo

Country where clinical trial is conducted

Brazil, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Optimal PEEP value	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	6 minutes	No
Secondary	Pulmonary atelectasis	The amount of atelectasis, in percentage of lung mass, evaluated by EIT during intraoperative period and by chest CT scan after extubation	2-5 hours	No
Secondary	Ultrasound evaluation	The use of ultrasound as a tool for PEEP titration intraoperatively compared to EIT	6 minutes	No