IJCS | Volume 31, Nº3, May/ June 2018

DOI: 10.5935/2359-4802.20180018 244 ORIGINAL ARTICLE International Journal of Cardiovascular Sciences. 2018;31(3)244-249 Mailing Address: André Luiz Lisboa Cordeiro Rua Japão, 94. Postal Code: 44052-022, Caseb, Feira de Santana, BA - Brazil. E-mail: andrelisboacordeiro@gmail.com Association of Respiratory Mechanics with Oxygenation and Duration of Mechanical Ventilation After Cardiac Surgery André Luiz Lisboa Cordeiro, 1 Livia Freire de Lima Oliveira, 2 Thaynã Caribé Queiroz, 2 Verena Lourranne Lima de Santana, 2 Thiago Araújo de Melo, 3 André Raimundo Guimarães, 4 Bruno Prata Martinez 5 Escola Bahiana de Medicina e Saúde Pública; 1 Salvador, BA - Brazil Faculdade Nobre; 2 Feira de Santana, BA - Brazil Universidade Salvador; 3 Salvador, BA - Brazil Incardio Instituto Nobre de Cardiologia; 4 Feira de Santana, BA - Brazil Universidade do Estado da Bahia (UNEB); 5 Salvador, BA - Brazil Manuscript received June 27, 2017; revised manuscript August 28, 2017; accepted September 25, 2017. Abstract Background: Mechanical ventilation (MV) and extracorporeal circulation (ECC) are associated with a decline in pulmonary mechanics that may affect gas exchange. Objective: To evaluate the impact of pulmonary mechanics on MV duration and gas exchange in the postoperative period of cardiac surgery. Methods: This was a cohort study in patients undergoing cardiac surgery. All patients underwent evaluation of pulmonary mechanics (static compliance and airway resistance) and arterial blood gas analysis upon admission to the intensive care unit (ICU) and were followed up until extubation and hospital discharge. Results: The study included 50 patients (46 women, 52%) with a mean age of 57.5 ± 13.5 years. The MV duration was 7.7 ± 3.0 hours, static compliance was 35.5 ± 9.1 cm H 2 O, resistance was 6.0 ± 2.3 cm H 2 O, mean length of ICU stay was 2.9 ± 1.1 days, and oxygenation index was 228.0 ± 33.4 mmHg. No significant correlation was found between MV duration and static compliance (p = 0.73), but a strong correlation was found between static compliance and gas exchange (r = 0.8 and p < 0.001). Conclusion: Pulmonary mechanics have a strong correlation with gas exchange and a weak correlation with MV duration after cardiac surgery. (International Journal of Cardiovascular Sciences. 2018;31(3)244-249) Keywords: Respiration, Artificial; Oxygenation; Thoracic Surgery; Cardiac Surgical Procedures; Postoperative Care. Introduction Cardiac surgery is a form of treatment for coronary and myocardial pathologies aimed at increasing the patient’s survival and quality of life. However, this type of surgery is associated with deleterious effects on the main body systems, such as the cardiovascular, central nervous, digestive, renal, and respiratory systems. 1 In this context, pulmonary complications emerge as an important cause of increased morbidity and mortality during the postoperative period. 2 Patients undergoing cardiac surgery remain under mechanical ventilation (MV) in the immediate postoperative period until properly awaken and presenting good respiratory and hemodynamic stability. 3,4 In some cases, the hospital stay may be even longer, and the patient may remain in the hospital for several days, often due to a requirement for vasoactive drugs. Complications caused by cardiac surgery lead to multifactorial changes in pulmonary function, including alveolar collapse, decreased functional residual capacity, secretion retention, and decreased cough effectiveness. 5,6