IJCS | Volume 31, Nº3, May/ June 2018

248 Cordeiro et al. Respiratory mechanics and oxygenation International Journal of Cardiovascular Sciences. 2018;31(3)244-249 Original Article oxygenation index. Rodrigues et al. 13 assessed 942 patients in order to verify the factors associated with dysfunctional exchanges after cardiac surgery and observed that the presence of pneumonia, cardiac arrhythmia, and hemotherapy correlated with such dysfunction. Other authors have demonstrated that the body mass index and smoking may be associated with hypoxemia, which in turn is associated with a decline in pulmonary compliance. 14,15 As an alternative to correct this decline in pulmonary compliance, Lima et al. 16 investigated the impact of different levels of PEEP on gas exchange in patients undergoing CABG. The authors evaluated 78 individuals divided into three groups according toPEEP level (5, 8, and 10 cm H 2 O) and observed that changes in PEEP level do not interfere in the exchanges. When the authors analyzed the group that received a PEEP of 5 cm H 2 O (an identical level to that used in the present study), they observed a mean value of 320.5 ± 65.0 mmHg, whereas in the current study, the mean value was 228.0 ± 33.4 mmHg. The limitations of the present study include the lack of information regarding the comorbidities presented by the patients included in the analysis. Another limitation was the lack of information about static compliance, resistance, and gas exchange in the preoperative period. Conclusion Based on the findings of this study, we conclude that pulmonary mechanics correlate strongly with gas exchanges and weakly with the duration of MV in the postoperative period of cardiac surgery. Author contributions Conception and design of the research: Oliveira LFL, Queiroz TC, Santana VLL, Cordeiro ALL. Acquisition of data: Oliveira LFL, Queiroz TC, Santana VLL. Analysis and interpretation of the data: Cordeiro ALL, Melo TA. Statistical analysis: Cordeiro ALL, Melo TA. Writing of the manuscript: Oliveira LFL, Queiroz TC, Santana VLL, Cordeiro ALL. Critical revision of the manuscript for intellectual content: Melo TA, Guimarães AR, Martinez BP. Potential Conflict of Interest No potential conflict of interest relevant to this article was reported. Sources of Funding There were no external funding sources for this study. Study Association This study is not associated with any thesis or dissertation work. Ethics approval and consent to participate This study was approved by the Ethics Committee of the Faculdade Nobre under the protocol number 1.405.817. All the procedures in this study were in accordance with the 1975 Helsinki Declaration, updated in 2013. Informed consent was obtained from all participants included in the study. 1. Umeda IIK. Manual de fisioterapia na reabilitação cardiovascular. São Paulo: Editora Manole; 2006. ISBN: 852041477x. 2. Padovani C, Cavenaghi OM. Alveolar recruitment in patients in the immediate postoperative period of cardiac surgery. Rev Bras Cir Cardiovasc. 2011;26.1:116-21. doi: http://dx.doi.org/10.1590/S0102- 76382011000100020. 3. Barbosa e Silva MG, Borges DL, Costa Mde A, Baldez TE, Silva LN, Oliveira RL, et al. Application of mechanical ventilation weaning predictors after elective cardiac surgery. Braz J Cardiovasc Surg. 2015;30(6):605-9. doi: 10.5935/1678-9741.20150076. 4. Gonçalves JQ, Martins RC, Andrade AP, Cardoso FP, MeloMH. Weaning frommechanical ventilation process at hospitals in Federal District. Rev Bras Ter Intensiva. 2007;19(1):38-43. http://dx.doi.org/10.1590/S0103- 507X2007000100005 5. Hachenberg T, Tenling A, Rothen HU, Nyström SO, Tyden H, Hedenstierna G. Thoracic intravascular and extravascular fluid volumes in cardiac surgical patients. Anesthesiology. 1993;79(5):976-84. PMID: 8239016. 6. Babik B, Asztalos T, Petak F, Deak Z, Hantos Z. Changes in respiratory mechanics during cardiac surgery. Anesth Analg. 2003;96(5):1280-7. PMID: 12707120. 7. Arcênio L, SouzaM, Bortolin B, Fernandes A, Rodrigues A, Evora P. Pre- and postoperative care in cardiothoracic surgery: a physiotherapeutic approach. Rev Bras Cir Cardiovasc. 2008;23(3):400-10. doi: http://dx.doi . org/10.1590/S0102-76382008000300019. 8. Badenes R, Lozano A, Belda FJ. Postoperative pulmonary dysfunction and mechanical ventilation in cardiac surgery. Crit Care Res Pract. 2015;2015:420513. doi: 10.1155/2015/420513. 9. Auler JO Jr, Carmona MJ, Barbas CV, Saldiva PH, Malbouisson LM. The effects of positive end-expiratory pressure on respiratory system mechanics and hemodynamics in postoperative cardiac surgery patients. Braz J Med Biol Res. 2000;33(1):31-42. http://dx.doi.org/10.1590/S0100- 879X2000000100005. 10. Canver CC, Chanda J. Intraoperative and postoperative risk factors for respiratory failure after coronary bypass. Ann Thorac Surg. 2003;75(3):853-7. PMID: 12645706. References