Avaliação funcional respiratória e capacidade do exercício como fatores de risco para complicações pulmonares no pós-operatório de transplante hepático

Abstract

Background: Liver transplantation (LT) is the current standard therapy for patients with irreversible liver failure, both acute or chronic. Pulmonary complications postoperatively (CPP) are an important cause of disease in liver transplant recipients and contribute substantially to mortality. Objective: To evaluate the respiratory functional evaluation and exercise capacity as independent risk factors for pulmonary complications after liver transplantation. Methods: Prospective cohort study undertaken at the Hospital Universitário Walter Cantídio (HUWC) from December 2012 to January 2015 with patients who are candidates for liver transplantation in the HUWC a total sample of 100 patients. The study included patients aged 18 to 70 years without hepatic encephalopathy, walking difficulties, orthopedic impairments. The patients were submitted to a preoperative evaluation consisting of clinical assessment, physical examination and laboratory tests (spirometry, maximal inspiratory pressure (MIP) and expiratory (MEP) for the manometer, 6-minute walk test (6MWT) and 6- minute step test (6MST'). In the post-operative, intraoperative data and post-operative data such as pulmonary complications were studied. In addition, lung function (forced expiratory volume in 1 second - FEV1) and manometer were analyzed on the 1st, 3rd and 5th post-operative days. One month after surgery, patients were evaluated for respiratory functional capacity and exercise capacity. The Research Ethics Committee of HUWC approved the study. Results: Among the 100 patients studied, 65% were male, the median age was 54.5 years and a higher prevalence for viral hepatitis (56%) as a cause for liver transplantation. The incidence of CPP was 49%. The rate of the most frequent pulmonary complications were pulmonary infection (32%), followed by acute respiratory failure (28%), the need for mechanical ventilation for more than 48 hours (14%), atelectasis (13%), pleural effusion requiring thoracentesis (7%) and bronchospasm (3%). The independent risk factors for the development of CPP were cold ischemia time greater than five hours, 6MWT less than 320 m and 6MST less than 60 steps. The pulmonary function, in the first, third and fifth post-operative days showed a decrease of 64%, 56% and 48% in FEV1, 56%, 44% and 33% in MIP and 55%, 46% and 38% in MEP (p = 0.001). With thirty days post-operatively all values of the variables were similar to the value of preoperative, showing a linear growth. The values of the 6MWT and the 6MST showed better results compared to preoperative 348 m to 367 m and 71 to 79 steps respectively. Of the 49 patients with CPP, 20 died. Conclusion: This study can be a useful tool for transplant centers allowing to evaluate objectively exercise capacity through the 6MWT and 6MST and identify candidates with a higher risk of developing pulmonary complications. There is a decrease in lung performance in the postoperative period with a recover 1 month after surgery.