Long term effect of coaxial double lumen tube ventilation associated with moderately high breathing frequency on lungs protection and function in an experimental model of acute respiratory distress syndrome

• Grant number: 17/16180-9
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: November 22, 2017
• End date: March 25, 2018
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Marcelo Britto Passos Amato
• Grantee: Nadja Cristinne Silva Carvalho
• Supervisor: Anders Larsson
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Uppsala University (UU), Sweden
• Associated to the scholarship: 15/22751-3 - Low volume ventilation strategy using a coaxial double-lumen tube: viability and effects on lung function and protection., BP.PD

Abstract

Studies have shown that an additional reduction of tidal volume (TV<6ml/kg) that promotes a reduction in the driving pressure can cause less injury and pulmonary inflammation determining reduction in mortality. However, the use of low TV is associated with hypercapnia and respiratory acidosis. There are two easy-to-carry out interventions to optimize the CO2 clearance: increase of respiratory rate and reduction of instrumental dead-space. Encouraging results from the applicant, showed that the coaxial tube ventilation strategy (i.e. association of moderately high respiratory rate and reduced dead space) allowed a further reduction of TV, reaching levels of 3 ml/kg, while keeping levels of PaCO2 stable and considerably reduced the driving pressure from 30 cmH2O (TV=6 ml/kg) to 23 cmH2O (TV=3 ml/kg), which has been preconized as an index more strongly associated with survival than TV, per se, in ARDS patients. However, recently it was postulated that ventilator-induced lung injury (VILI) was not due to the TV per se, but due to the product of TV, plateau pressure, and respiratory rate. Thus, it is essential to investigate the impact of moderately high respiratory rate associated with coaxial tube ventilation on lung protection, before considering its use for patients. The ideal technology to perform this assessment would be 18F-FDG PET imaging of the lungs. The host group for this study posses the technology and the knowhow to perform this type of imaging and will provide full financial support to perform 10 experiments, approximately 35.000 USD and tutoring on their established experience on acquisition and processing of PET.